STATUS AND TRENDS OF BIODIVERSITY OF INLAND WATER

Status an

d Trends of

Biodiversity of

Inlan

d Water E

cosystems

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ical Series No.11

11STATUS AND TRENDS OF BIODIVERSITYOF INLAND WATER ECOSYSTEMS

CBD Technical Series No.Secretariat of the Convention onBiological Diversity

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Issue 1: Assessment and Management of Alien Species that Threaten Ecosystems,Habitats and Species

Issue 2: Review of the Efficiency and Efficacy of Existing Legal Instruments Applicableto Invasive Alien Species

Issue 3: Assessment, Conservation and Sustainable Use of Forest Biodiversity

Issue 4: The Value of Forest Ecosystems

Issue 5: Impacts of Human-Caused Fires on Biodiversity and Ecosystem Functioning,and Their Causes in Tropical, Temperate and Boreal Forest Biomes

Issue 6: Sustainable Management of Non-Timber Forest Resources

Issue 7: Review of the Status and Trends of and Major Threats to Forest BiologicalDiversity

Issue 8: Status and Trends of and Threats to Mountain Biodiversity, Marine, Coastaland Inland Water Ecosystems: Abstracts of poster presentations at the eighthmeeting of the Subsidiary Body of Scientific, Technical and TechnologicalAdvice of the Convention on Biological Diversity

Issue 9: Facilitating Conservation and Sustainable Use of Biodiversity: Abstracts ofposter presentations on protected areas and technology transfer and coopera-tion at the ninth meeting of the Subsidiary Body on Scientific, Technical andTechnological Advice

Issue 10: Interlinkages Between Biological Diversity and Climate Change: Advice onthe integration of biodiversity considerations into the implementation of theUnited Nations Framework Convention on Climate Change and its KyotoProtocol

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STATUS AND TRENDS OF BIODIVERSITYOF INLAND WATER ECOSYSTEMS

December 2003

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Published by the Secretariat of the Convention onBiological Diversity ISBN: 92-807-2398-7

Copyright © 2003, Secretariat of theConvention on Biological Diversity

The designations employed and the presentationof material in this publication do not imply theexpression of any opinion whatsoever on the partof the World Resources Institute, WetlandsInternational, the Netherlands Ministry of ForeignAffairs (DGIS), the Bureau of the RamsarConvention on Wetlands or the Secretariat of theConvention on Biological Diversity concerning thelegal status of any country, territory, city or area orof its authorities, or concerning the delimitation ofits frontiers or boundaries.

The views expressed in this publication are those ofthe authors and do not necessarily reflect those of theWorld Resources Institute, Wetlands International,the Netherlands Ministry of Foreign Affairs (DGIS),the Bureau of the Ramsar Convention on Wetlands,Wetlands International or the Secretariat of theConvention on Biological Diversity.

This publication may be reproduced for educa-tional or non-profit purposes without special per-mission from the copyright holders, providedacknowledgement of the source is made. TheSecretariat of the Convention on BiologicalDiversity would appreciate receiving a copy of anypublications that use this document as a source.

CitationRevenga, C. and Y. Kura. 2003. Status and Trends ofBiodiversity of Inland Water Ecosystems. Secretariatof the Convention on Biological Diversity,Montreal, Technical Series no. 11.

For further information please contact:Secretariat of the Conventionon Biological DiversityWorld Trade Centre, 393 St. Jacques, Suite 300,Montreal, Quebec, Canada H2Y 1N9Phone: 1 (514) 288 2220Fax: 1 (514) 288 6588E-mail: [email protected]: http://www.biodiv.org

Status and trends of biodiversity of inland water ecosystems

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That water is important to life on earth, includingfor sustaining human populations, is self-evidentto most of us. What is less widely appreciated isthat out of the world’s total water resources, lessthan 3% is represented by freshwater and less than1% of that (less than 0.01% of total water) occursin the earths liquid surface freshwater (the remain-der being locked in ice-caps or as groundwater,below the planet’s surface). This fraction of wateravailable on earth is home to an extraordinarilyhigh level of biodiversity that is directly supportedthrough a range of freshwater ecosystem types thatincludes running waters in rivers, standing watersof lakes and marshes and areas of transient wateravailability in seasonal or ephemeral wetlands.These inland water ecosystems provide a vital rangeof goods and services essential for sustaininghuman well-being.

The complexity, and variability in space andtime, of these ecosystems is still being documentedby scientists but their importance is unquestioned.Witness for example, the fact that all major civi-lizations have evolved in association with river sys-tems, as confirmed today by the location of mostmajor cities. Humans need freshwater not only fordrinking, but also for agriculture, industry, trans-portation and many other important uses. But ashuman populations have grown, and consumptiveuses of water increased, our activities have takenan enormous toll on the global freshwaterresource. Not only are we over-consuming a veryvaluable and finite resource, and the life it sup-ports, we are abusing it by, for example, allowingpollution from activities on the land to flow intorivers, to be transported for eventual dilution inthe sea, or to be accumulated in lakes and otherwetlands. It is not surprising that the stresses wehave placed upon inland waters have resulted inthem now being considered amongst the mostthreatened global ecosystems.

We are starting to take notice of these prob-lems, and have begun efforts to address them.The Convention on Wetlands of International Impor-tance, especially as Waterfowl Habitat (Ramsar,Iran, 1971), commonly referred to as the “Ramsar

Convention”, was the first formal global inter-gov-ernment initiative to improve the sustainability oflife dependent upon inland waters. While theConvention on Biological Diversity (1992) covers allecosystem types and geographical regions, it hasidentified “inland waters” as an immediatelyimportant thematic area of work. A considerablenumber of local, national, regional and global ini-tiatives are also now focussing directly or indirectlyon conservation and sustainable use of inlandwaters, including many sponsored by non-govern-ment organisations such as Wetlands International,IUCN — The World Conservation Union, TheWWF for Nature and BirdLife International.

Our ability to identify the current status of, andsubsequently monitor, the biodiversity of inlandwaters and the ecosystem services they provide forthe planet is a fundamental requirement. If we can-not do this, we cannot assess our progress towardsmeeting key conservation and sustainable use goalsin this important area. In recognition of this fact,the Parties to the Convention on BiologicalDiversity have requested the Subsidiary Body onScientific, Technical and Technological Advice toreview this subject as a priority. We are pleased topresent this review as a joint effort between theConvention on Biological Diversity and the RamsarConvention to further illustrate their continued co-operation towards achieving important commongoals, and especially as a contribution towards theoverall goal of the World Summit on SustainableDevelopment of significantly reducing the rate ofloss of biodiversity by 2010.

The subject matter in this document is com-plex. Data and information are often lacking or, atbest, difficult to access. We present this document asneither a comprehensive nor a final text, but ratheras a starting point. “Trends”, by definition, inferanalysis over time. We hope that this document willbe upgraded and updated on a regular basis.


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FOREWORD

Hamdallah ZedanExecutive SecretaryConvention onBiological Diversity

Peter BridgewaterSecretary GeneralConvention on Wetlands(Ramsar, Iran, 1971)

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The support of the World Resources Institute inthis process is acknowledged. Preparation of thisreport was made possible through financial sup-port from the Dutch Ministry of Foreign Affairs(DGIS) under the “Conservation and Wise Use ofWetlands — Global Programme” managed byWetlands International (WI) as part of a GrantAgreement between WI and the Bureau of theRamsar Convention on Wetlands. It draws heavilyon material previously published by the WorldResources Institute and contains sections previ-ously published in Revenga, C., J. Brunner, N.Henninger, K. Kassem, and R. Payne. 2000. Pilotanalysis of global ecosystems: freshwater systems.World Resources Institute, Washington DC.

Copyright for these verbatim sections remains withthe World Resources Institute.

The original draft was peer reviewed by anumber of specialists at the Secretariat of theConvention on Biological Diversity, the Bureau ofthe Ramsar Convention on Wetlands and WetlandsInternational and externally. A number of special-ists contributed additional materials to the reportduring this process. The Secretariat of theConvention on Biological Diversity wishes toacknowledge all these efforts in the production ofthis document.

Hamdallah ZedanExecutive Secretary


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Acknowledgements

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1. In paragraph 8 (a) of the programme of workon inland water ecosystems contained inAnnex I to decision IV/4, the Subsidiary Bodyon Scientific, Technical and TechnologicalAdvice (SBSTTA) was requested to use exist-ing information and draw upon relevantorganizations and experts to develop, as partof its work plan, an improved picture ofinland water biological diversity, its uses andits threats, around the world, and to highlightwhere the lack of information severely limitsthe quality of assessments.

2. To assist SBSTTA in implementing this task,the Executive Secretary commissioned theWorld Resources Institute (WRI) to preparethis report of the status and trends of inlandwater biodiversity. The Executive Secretary haspreviously prepared a short version of thisreport (UNEP/CBD/SBSTTA/8/8/Add.1). Thepresent note overviews the distribution andextent of inland water ecosystems, and pres-ents a review of inland water species, majorpressures upon them, and some conclusionsregarding gaps in information.

3. In general, the extent and distribution of inlandwater ecosystems are not properly documentedat the global or regional scale and, in somecases, there is no comprehensive documenta-tion even at the national levels. Several inven-tories have been published listing the majorriver systems with their drainage area, lengthand average runoff. The International LakeEnvironment Committee (ILEC) and theUNEP-World Conservation Monitoring Center(WCMC)’s global map of wetlands, amongothers, maintain geographic descriptions,and/or physiographic, biological and socio-eco-nomic information on lakes. They do not pro-vide comprehensive information on thedistribution and extent of lakes at the globallevel. There are about 10,000 lakes with a sizeover 1km2 worldwide. The location and distri-

bution of stricto sensu wetlands i.e. areas thatare often transitional and can be seasonally orintermittently flooded, and other classes ofinland waters such as underground water andhuman-made systems are not well documentedexcept in North America and Western Europe.Information on the status and trend of wateravailability and quality is also generally lacking.

4. The important relationships between inlandwaters, the biodiversity it supports and thelivelihoods of people are not well document.Most reviews are based upon the FAOFisheries Statistics which are acknowleded tobe weak on this subject and seriously under-estimate true values of the resource. Muchimproved information on production, thelevel of livelihoods dependency upon and theextent of utilisation of inland waters biodiver-sity is urgently required.

5. Major microbial groups present in inlandwaters include viruses, bacteria, fungi, proto-zoa and algae. Aquatic plants includeangiosperms (flowering plants), pterophytes(pteridophytes, ferns), bryophytes (mosses,hornworts, and liverworts) and a number oftree species. Information on invertebratespecies diversity is fragmentary. With regardto vertebrates, most global and regionaloverviews of inland water biodiversity includemore information on the diversity of fishesthan most other inland water groups, includ-ing inter alia amphibians, reptiles, and mam-mals. Waterbirds tend to have better coverage.

6. In general, information on species importantfor conservation pursuant to Annex I of theConvention, is generally fragmentary and, ina number of countries and regions, lacking forsome categories of inland water biodiversity,particularly for species of socioeconomic, sci-entific and cultural value. Similarly, relatedinformation for genetic diversity (including


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EXECUTIVE SUMMARY

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genomes, strains, varities, populations etc.) iseven more fragmentary as is accurate data forecosystem diversity. This information needs tobe improved to be more useful to policy anddecision-makers.

7. Microorganisms are rarely part of biodiver-sity status assessments, in spite the fact thattheir role in nutrient cycling, water purifica-tion and the food web is well known.Information on the conservation status ofplants and animals was synthesized frominternet checklists of specific animal and plantfamilies and existing databases, mainly thoseof threatened species such as inter alia the2002 IUCN Red Lists of Threatened Speciesand previous IUCN Red Lists, the UNEP-WCMC Threatened Plants Database and theBirdLife International Threatened Birds of theWorld. In every group of organisms consid-ered, including aquatic plants and inverte-brate and vertebrate animal species, examplesof extinct, critically endangered, endangered,and vulnerable taxa are given. Some of themain threats to these taxa are also listed.Based upon these sources of information, it isclear that inland waters are amongst the mostthreatened of all environments.

8. Major threats to inland water ecosystemsinclude, inter alia, modification of river systemsand their associated wetlands, water with-drawals for flood control or agriculture, intro-duction of invasive alien species, pollution andeutrophication, overharvesting and the impactof climate change. These pressures occur allover the world. Their reported impacts varyfrom one watershed to another and are con-sidered to be largely underestimated.

9. In conclusion, it is noted that(a) Additional efforts and financial commit-

ments are needed to improve national,regional and global data on components

of inland water ecosystems, their extent ,functioning and response to pressures,the livelihoods dependency of peopleupon inland water biodiversity andrelated socioeconomic information;

(b) Most data on water availability and use,including ground water, and such vari-ables as river flow, water withdrawals andaquifer recharge rates, are generally onlyavailable at the national level, whichmakes it difficult to manage river basinsthat cross national borders;

(c) New initiatives will assist in filling thelarge information gap regarding inlandwater species, especially at lower taxo-nomic orders. They include inter alia themonitoring projects sponsored by theIUCN’s freshwater biodiversity assess-ment and species mapping programs; thework being done by BirdLife interna-tional on the location, distribution andpopulation status of birds; the OECD’sGlobal Biodiversity Information Facility(GBIF); the states of the world’s plant andanimal genetic resources for food andagriculture of the Food and AgricultureOrganization of the United Nations, theGlobal Taxonomy Initiative of theConvention on Biological Diversity andthe European Space Agency. These initia-tives could also assist in mapping seasonaland forested wetlands which are difficultto map by other means;

(d) Most species inventories are organized bytaxonomic group. This should be broad-ened to include genetic diversity. It wouldbe useful to also carry out inventories byecosystem type to allow an assessment ofthe condition of inland water ecosystems;this should include accurate diagnosticsof the temporal dimension on inlandwater ecosystems, in particular the hydro-logical regimes of rivers and the associ-ated seasonal changes of wetlands;


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(e) In order to obtain information of trends,baseline information will have to begathered. Without population trends ofspecies, it is hard to assess the effects ofpressures or the risk of extinction ofspecies. Tracking changes in habitat extentand quality also requires appropriate base-line information. An agreement on out-come targets such as the ones defined inthe Convention’s Strategic Plan and in theGlobal Strategy for Plant Conservation ofthe Convention would facilitate the devel-opment of monitoring mechanisms thatcould provide information on trends ininland water biodiversity;

(f) Because of the large impact that intro-duced species can have on inland waterecosystems, information on the locationof introduced and alien invasive speciesis urgently needed.


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4

TABLE OF CONTENTS

FOREWORD ..............................................................................................................................................iii

ACKNOWLEDGEMENTS ..........................................................................................................................iv

EXECUTIVE SUMMARY ............................................................................................................................1

TABLE OF CONTENTS................................................................................................................................4

1. INTRODUCTION ..................................................................................................................................71.1 Limitations of this report ............................................................................................................71.2 Distribution and extent of inland water ecosystems ..................................................................81.3 Extent and distribution of wetlands............................................................................................91.4 Extent and distribution of rivers ..............................................................................................111.5 Extent and distribution of lakes ................................................................................................14

2. CONDITION OF, AND THREATS TO, INLAND WATER ECOSYSTEMS ........................................172.1 Modification of river systems ....................................................................................................172.2 Water scarcity ............................................................................................................................202.3 Invasive alien species..................................................................................................................212.4 Fisheries exploitation ................................................................................................................242.5 Effects of climate change ..........................................................................................................25

3. REVIEW OF INLAND WATER SPECIES RICHNESS,DISTRIBUTION AND CONSERVATION STATUS ..................................................................................29

3.1 Aquatic plants ............................................................................................................................293.2 Fungi..........................................................................................................................................303.3 Aquatic insects ..........................................................................................................................313.4 Water mites ..............................................................................................................................343.5 Freshwater molluscs ..................................................................................................................353.6 Freshwater crustaceans ..............................................................................................................403.7 Rotifera ......................................................................................................................................423.8 Freshwater fish ..........................................................................................................................423.8 Amphibians................................................................................................................................493.9 Reptiles ......................................................................................................................................503.10 Birds ........................................................................................................................................563.11 Mammals ................................................................................................................................67

4. INLAND WATER ECOSYSTEMS AND HABITATS IDENTIFIED AS HIGH CONSERVATION PRIORITY ............................................................................81

4.1 Summary of the IUCN method for prioritizing important areas for freshwater biodiversity 814.2 Habitats identified as high conservation priority for birds ......................................................824.3 Habitats identified as high conservation priority for multiple taxa ........................................82



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5. DATA GAPS AND INFORMATION NEEDS ........................................................................................875.1 Habitat inventory and indicators of condition and change ....................................................875.2 Species information ..................................................................................................................885.3 Water resource information ....................................................................................................895.4 Socio-economic data ................................................................................................................90

6. REFERENCES ........................................................................................................................................91

ANNEX I: REVIEW OF SOME ONGOING ASSESSMENTS AND INITIATIVES ON WATER RESOURCES AND INLAND WATER BIODIVERSITY......................................................107

1. IUCN’s Freshwater Biodiversity Assessment ............................................................................1072. IUCN/Species Survival Commission Species Information Service ..........................................1073. WWF-US Freshwater Ecoregional Assessments ........................................................................1084. WWF Water and Wetland Index for Europe ............................................................................1085. Declining Amphibian Populations Task Force (DAPTF)..........................................................1096. BirdLife International’s Important Bird Areas ..........................................................................1097. Species 2000 Programme ..........................................................................................................1108. Conservation International’s AquaRAP and Freshwater Biodiversity Hot-Spots ....................1109. The Nature Conservancy’s Freshwater Initiative ......................................................................11010. Millennium Ecosystem Assessment (MA) ..............................................................................11111. Global International Water Assessment (GIWA) ....................................................................11112. United Nations World Water Assessment Programme (WWAP) ..........................................11113. World Water Council ..............................................................................................................11214. Global Water Partnership ........................................................................................................11215. Global Dialogue on Water, Food and Environment................................................................11316. CGIAR Challenge Program on Water and Food ....................................................................11317. Comprehensive Assessment of Water Management in Agriculture ........................................11418. LakeNet’s World Lakes Biodiversity Conservation Initiative ..................................................115

APPENDIX A: MAPS................................................................................................................................117



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The programme of work on the biological diver-sity of inland water ecosystems was adopted at thefourth meeting of the Conference of the Parties tothe Convention on Biological Diversity as annex Ito decision IV/4. The first programme elementrelates to the assessment of the status and trends ofthe biological diversity of inland water ecosystemsand the identification of options for conservationand sustainable use. In paragraph 5 of decision V/2,adopted in 2000, the Conference of the Partiesrequested the Subsidiary Body on Scientific,Technical and Technological Advice (SBSTTA) toreview the implementation of this programme ofwork and to include in its review advice on the fur-ther elaboration and refinement of the programmeof work. The CBD and Convention on Wetlandsalso have a joint work programme.

This report, prepared by the World ResourcesInstitute (WRI) for the CBD and the RamsarConvention, provides an overview of the currentknowledge of the condition of inland water ecosys-tems and their biodiversity. It reviews the currentknowledge and information on inland waterecosystems and their dependent species in order toidentify information gaps and needs that should beaddressed by the CBD programme of work on thebiological diversity of inland water ecosystems.

The document consists of five major sectionscovering the following topics:1. Distribution and extent of inland water

ecosystems;2. Overview of the condition and threats to

inland water ecosystems (focusing on the frag-mentation of river systems, water scarcity, pol-lution, habitat loss, invasive alien species,fisheries exploitation, and the impacts of cli-mate change);

3. Review of knowledge of inland water biodi-versity. This section reviews the distribution,richness and conservation status of freshwa-ter-dependent taxa (i.e., mammals, birds,amphibians, reptiles, fish, invertebrates andaquatic plants);

4. Identification of habitats and ecosystemsthat have been identified as conservation pri-ority areas through different priority-settingapproaches;

5. Identification of data gaps and future assess-ments needs.

The report includes an annex describing ongoingassessment or monitoring programmes that focuson water resources and freshwater biodiversity.

1.1 LIMITATIONS OF THIS REPORT

An exhaustive literature review of all existinginformation on taxa that include freshwaterspecies was not attempted in this review. The doc-ument therefore relies heavily on existing andavailable information provided by experts of theSpecies Survival Commission network of theWorld Conservation Union (IUCN/SSC) andother organizations working on biological diver-sity such as the WWF, and the United NationsEnvironment Programme-World ConservationMonitoring Centre (UNEP-WCMC). The docu-ment is based in part on previously publishedmaterials and analyses from the World ResourcesInstitute (WRI) and on readily available informa-tion from well-documented and peer-reviewedsites on the Internet, and literature publishedprimarily in the English language. For sometaxa, Japanese, French and Spanish publicationswere used.

This report is global and to certain extentregional in scope, therefore only information at theglobal and/or regional scale was consulted. Thereis considerable knowledge and information at thenational level, particularly on certain speciesgroups. However it was not possible to consult orincorporate such information for this report.

Coverage of the uses of inland water biodiver-sity is not comprehensive. Data for this are hard tocome by. In references to the FAO statistics for inlandfisheries, for example, it should be noted that theseare acknowledged by the FAO itself as seriouslyunderestimating the importance of inland water bio-


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1. INTRODUCTION


diversity, and in particular do not adeqately coversmall-scale uses or livelihoods aspects (www.fao.org).It is widely known that the existing uses of inlandwater biodiversity, and the levels of livelihoodsdependency upon it, is one of the most significantbenefits of the resource. A more thorough review ofthis subject would have particular relevance to Article10 (on sustainable use) of the Convention.

Coverage of genetic diversity in inland watersis limited and refers mainly to genetic diversityimplied by populations or sub-populations of alimited number of animals, particularly birds. Thenature of inland water ecosystems promotes veryhigh levels of genetic diversity (i.e., diversitywithin species, of varieties, strains, populationsetc.). This is often because groups of freshwaterorganisms can be isolated from one anotherbetween, and even within, catchments (basins),including those which are geographically veryclose, even adjacent.

The diversity of inland water ecosystems andhabitats (as a component of biodiversity in its ownright) is another area that is difficut to review, notleast because of constraints with, and differencesin, classification systems and terminology. In par-ticular, the temporal aspects of ecosystem diversityin inland waters (e.g. seasonal wetlands, hydrolog-ical cycles in rivers) are especially difficult to quan-tify but nevertheless are perhaps more marked ininland waters than in any other ecosystem type.

Amongst the taxa covered, microorganismsremain a significant ommission. Until recently, thesebiota have tended to be poorly studied and typicallynegelected in assessments of the biodiversity ofaquatic ecosystems. Nowadays, the important rolesplayed by these organisms in maintaining manybiological and geological processes in inland waterecosystems are gradually becoming understood, as

are the implications of the loss of such elements ofbiodiversity. The largely unexplored potential ofmicroorganisms, such as protozoa, as indicators ofecosystem health or condition is another area thatrequires further attention and research focus.

All of these areas, amongst others, would ben-efit from more focussed additional attention.

1.2 DISTRIBUTION AND EXTENT OFINLAND WATER ECOSYSTEMS

Inland water ecosystems encompass habitats with awide variety of physical, temporal, chemical and bio-logical characteristics, and include lakes and rivers,floodplains, peatlands, marshes and swamps, smallstreams, ponds, springs, cave waters, and even verysmall pools of water in tree holes and other cavitiesin plants and soil. The terms “inland waters” and“freshwater”are often used interchangeably. However,some important inland water ecosystems are salineor brackish (e.g., lagoons, inland seas or lakes) andnot freshwater. Also “freshwaters” can extend a con-siderable distance out into the sea (at large rivermouths where water is still potable several kilome-tres offshore) but such areas of freshwater influenceare not usually covered by the term “inland waters”.The temporal dimension of inland water bodies canbe perennial or ephemeral and includes the dynamicdimension of running systems (i.e., rivers or lotic sys-tems), standing systems such as lakes and ponds (i.e.,lentic systems) and the seaonality of inundation ofwetlands (UNEP/CBD/SBSTTA/3/7 and UNEP-WCMC 2000).

The remainder of this section of the reportprovides an overview of what is known about thedistribution of the world’s inland water ecosystemsand highlights some of the limitations and difficul-ties encountered by the research and conservation


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1 The most widely used definition of inland wetlands is that adopted by the Convention on Wetlands (Ramsar, Iran, 1971), whichcovers all wetland types, including artificial wetlands, occurring in inland situations, and encompasses riverine, lacustrine, and palus-trine systems (see Ramsar Classification System for Wetland Type in the Annex to Resolution VII.11, available onhttp://www.ramsar.org/key_res_vii.11e.htm). However, it should be noted that some definitions of “wetland” are more restrictive and,for example, cover only shallow vegetated systems, so excluding open water systems. Since the main sources of available informa-tion on global and regional wetland distribution used here report on all inland water types covered by the Ramsar Convention, theRamsar inland wetland scope is used in this section.


community in mapping and inventorying theseecosystems around the world.

1.3 EXTENT AND DISTRIBUTIONOF WETLANDS

In this section, the term “wetland”1 covers all nat-ural and artificial inland water habitat types cov-ered by the Ramsar Convention, includingfreshwater, brackish and saline systems, permanentand temporary systems and above ground andunderground (karst and cave) systems.

In most cases there is no clear boundarybetween inland and coastal systems, and there isan array of wetland habitats that have either salineor freshwater attributes or a mixture of the twoseasonally (UNEP/CBD/SBSTTA/3/7 and UNEP-WCMC 2000). Many seasonal and ephemeralwetlands are estimated to disappear in the com-ing 100 years (Bledzki, pers. comm. 2003). Thecomplex coupling of climatic, edaphic, and bioticfactors that drive ecosystem processes changequickly over both space and time. Furthermore,interactions between these processes promotethe persistence of rare species and the mainte-nance of critical ecosystem functions that woulddisappear with the loss of the ephemeral and sea-sonal wetlands.

A Global Review of Wetland Resources andPriorities for Wetland Inventory (GRoWI)(Finlayson & Spiers 1999) was prepared for theRamsar Convention. This derived estimates of theglobal extent of wetlands from compilation ofnational inventory sources, and from regional andglobal sources, and compared these with previousestimates. An overall global estimate, includingcoastal wetlands in some countries, was 1,276-1,279 million hectares, compared with previousestimates of inland waters of 530-970 millionhectares derived mostly from remotely sensedinformation. These estimates include 530 millionha for natural freshwater wetlands (i.e. excluding

irrigated rice fields) (Matthews & Fung 1987) and700 million ha (including rice paddies) (Aselmann& Crutzen 1989).

Global figures for the area and distribution ofdifferent inland water types are not generally avail-able. However, a substantial proportion of theinland water resource is known to be peatland 2.Although size estimates vary, peatlands are consid-ered to cover at least 242 million ha (Spiers 1999),and the Global Peatland Initiative has recently esti-mated coverage of 324 million ha (http://www.wetlands.org/projects/GPI/peatland.htm), some 25-46% of the total area of inland waters from differ-ent sources. Cultivated rice paddies also form asignificant area of the inland resource, covering atleast 130 million ha (Aselmann & Crutzen 1989).Further information on rivers and lakes is providedin Sections 1.4 and 1.5 below.

In interpreting all these estimates it is impor-tant to be aware that Finlayson & Spiers (1999)concluded that based on existing information itis not possible to reliably estimate the total extentof wetlands at a global scale, so all the estimatessummarised in Table 1 are indicative and shouldbe interpreted with caution. There are many rea-sons for the difficulty of establishing an accurateestimate of wetland extent and distribution (seeBox 1).

The GRoWI report concluded that nationaland regional data for Oceania, Asia, Africa, EasternEurope, and the Neotropics allow just a cursoryassessment of wetland extent and location. Only forNorth America and for Western Europe have morerobust estimates of wetland extent been published.Of 206 countries or territories for which the stateof inventory was assessed, only 7% had adequate orgood national inventory coverage. Of the remain-der, 69% had only partial coverage, and 24% hadlittle or no national wetland inventory (Finlayson& Davidson 1999). More detailed discussions oneach region, including country-specific assessments,are available in Finlayson & Spiers (1999).


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2 Peatlands are areas of landscape with a naturally accumulated peat layer on its surface, and include active peatlands (‘mires’) wherepeat is currently forming and accumulating (Ramsar Resolution VIII.17 Guidelines for Global Action on Peatlands)


In terms of mapped information, the best globalGIS database of wetlands currently available isUNEP-WCMC’s Global Wetland Distribution.UNEP-WCMC and IUCN estimated the locationand extent of the wetlands through expert opinionby delineating wetland boundaries fromOperational Navigation Charts (WRI 1995).

Unfortunately wetland characterization and thelevel of detail varies from region to region, withAfrica being the most comprehensively mapped,while most of North America is much less accu-rate. Map 1 (see Appendix A, page 117) showsUNEP-WCMC’s coverage of wetlands for Africatogether with the locations of Ramsar sites and


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Table 1. Estimates of Regional and Global Freshwater Wetland Area

Figures are in millions of hectares.

Region GRoWI (regionalization scheme compilation ofdiffers between GRoWI and national wetland Previous regional and UNEP-WCMCUNEP-WCMC sources ) inventories1 global estimates1 (1998) map2

Africa 111.6-112.23 34.5-35.65 132.4

Asia 207.44 > 1204 343.6

Europe 227.83 0.75 35.8

Neotropics 414.94 153.85 156

North America 241.64 167.34 –.6

Oceania 35.84 No data 20.5

Total 1,236.5 > 474.5-475.6 > 688.3

Sources: 1 Finlayson & Spiers (1999) and its global and regional reports; 2 UNEP-WCMC (1998)

Notes: 3 ‘inland’ and ‘human-made’ wetland types only; 4 all wetlands; 5 freshwater wetlands only; 6 area estimate not available —shown on map as percentage of area covered by wetlands.

Box 1Wetland inventories have been incomplete, are inconsistent in coverage and are difficult to undertake for a num-ber of reasons, including:• Definitions: The definition of a wetland varies depending on research purpose and an organization’s mandate.

For example, the Ramsar Convention uses a very broad definition, covering both inland waters and coastalzones. The latter includes reefs and seagrass beds as specific habitat types up to a water depth of six meters;

• Scope: Data from national inventories are often incomplete and difficult to compare with each other becausesome concentrate on specific habitat types, such as wetlands of importance to migratory birds, whereas oth-ers include artificial wetlands, such as rice paddies;

• Limitation of maps: Wetland inventories sometimes use existing maps, such as Operational Navigation Charts(ONC), to estimate wetland extent. Wetland extent then becomes a function of scale and the cartographic con-vention of the mapmaker. For example, navigation charts will depict only wetlands that are visible by pilots.In addition, the rules for placing wetlands symbols on a map usually vary with institutions;

• Boundaries: Researchers often have difficulty defining the boundaries and differentiating individual wetlandsfrom wetland complexes, often because of seasonal changes. Establishing inland water boundaries is a partic-ular challenge for temporary and ephemeral wetlands;

• Limitation of remote sensing products: The wide range in the sizes and types of wetlands and the problem ofcombining hydrologic and vegetation characteristics to define wetlands make it difficult to produce a global,economical, and high-resolution data set with existing sensors.


registered dams. UNEP-WCMC’s global map ofwetlands provides more detail than other global,coarse resolution data sets that use vegetation, soils,and terrain to delineate wetlands—for example,data produced to estimate methane emissions(Matthews and Fung 1987). It also provides moredetail on wetlands than the most recent land covercharacterization map by the InternationalGeosphere-Biosphere Programme (IGBP) of theInternational Council for Science (ICS), whichmostly shows coastal wetlands.

The University of Kassel in Germany has com-piled a global 1-minute resolution map of wet-lands, lakes and reservoirs. The map was derivedby combining various digital maps includingESRI’s 1992 and 1993 maps of wetlands, lakes andreservoirs, UNEP-WCMC’s map of lakes and wet-lands and the Vörösmarty et al. (1997a) map ofreservoirs. Attribute data on reservoirs and lakeswere also included from the InternationalCommission on Large Dams and other sources.The map distinguishes ‘local’ from ‘global’ lakesand wetlands, the local open-water bodies beingthose only supplied by the runoff generated withinthe grid-cell and not by additional inflow fromupstream areas. The resulting map is a generateddata set, in which vegetated wetlands cover 6.6% of

the global land area (without Antarctica andGreenland), and lakes and reservoirs cover 2.1%(Lehner and Döll 2001).

1.4 EXTENT AND DISTRIBUTIONOF RIVERS

Although the volume of water in rivers and streamsis only a fraction of the water in the entire hydros-phere, in many parts of the world this water con-stitutes the most accessible and important resource(WWDR 2003). Precipitation and runoff, whichinfluence the distribution of river networks, areunevenly distributed across the world. It is esti-mated that Asia and Latin America each contributeover 30% of the world’s freshwater discharged intothe ocean, while North America contributes 17,Africa 10, Europe 7, and Australasia 2% (Feketeet al. 1999).

There are several published inventories ofrivers, listing the major river systems with theirdrainage area, length, and average runoff (e.g.Baumgartner and Reichel 1975; Gleick 1993;Shiklomanov 1997). The variability between esti-mates can be explained by different definitionsregarding the extent of a river system and differenttime periods or locations for the measurement of


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Box 2 Calculating drainage area requires a definition of watersheds. Data on river networks and topography are essen-tial in determining the extent of a drainage basin. The Eros Data Center of the United States Geological Surveydeveloped a GIS database in 1999 called HYDRO 1K, which delineates basin boundaries at a scale of 1:1,000,000.HYDRO 1K is currently the most detailed global database that provides comprehensive and consistent coverageof topographically derived data sets with hydrologic modelling applications, including flow direction and drainagebasins. Some of the limitations of this database, however, are that most of the basins do not have the name of theriver system or the catchment, which makes manipulation and use difficult and many need to be edited, togetherwith a river coverage, to ensure that rivers do not cross basin boundaries. Global river networks have also beendigitally mapped by the U.S. National Imagery and Mapping Agency, at the scale of 1:1,000,000 based on theOperational Navigation Chart series (VMAP Level 0, 3rd edition, 1997). However, the only descriptive informa-tion contained in this database is whether the river is perennial or intermittent. Neither the name of the river sys-tem nor the catchment are included.

The World Meteorological Organization’s (WMO) Global Runoff Data Centre compiles and maintains a data-base of observed river discharge data from gauging stations worldwide. Although this is the best global databasecurrently available, the number of operating stations has significantly declined since 1980s—meaning the dis-charge data for many rivers have not been updated in the last two decades.


discharge. The commonly used virgin mean annualdischarge (VMAD) is an estimate of the discharge“before any significant human manipulation” ofthe river system has taken place (Dynesius andNilsson 1994). The VMAD is therefore usuallyhigher than discharge figures measured at themouth of the river, which often reflect consump-tive water usage upstream.

Table 2 presents the drainage basin areas basedon the currently available Geographic InformationSystem (GIS) data that has a globally consistentlevel of detail.

The coverage and reliability of hydrologicalinformation obtained through measurements

varies from country to country. Most scenarios andprojections for water use and water scarcity aretherefore derived from global models that utilise acombination of climate and elevation data and are,wherever possible, calibrated with observed data.These models do not supply the level of detailrequired to establish management options, assessthreats to species and ecosystems or evaluate trade-offs. Better and more reliable information on actualstream and river discharge, and the amount ofwater withdrawn and consumed at the river basinlevel, would increase our ability to manage inlandwater ecosystems more efficiently, evaluate trade-offs between different uses, and set conservation


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Table 2. Twenty Largest River Basins of the World (by drainage area)

Countries Virgin River/ Basin Areaa River Length Sharing the Mean Annual Lake Basin (km2) (km) Basin (Number) Discharge (m3/s)

Amazon 6,145,186 6280 - 6570 7 200,000

Congo 3,730,881 4370 - 4700 9 41,000

Nile 3,254,853 6484 - 6670 10 ~3,000

Mississippi 3,202,185 5970 - 6019 2 18,400

Ob 2,972,493 3180 - 5570 4 12,800

Parana 2,582,704 4700 - 4880 4 21,000

Yenisey 2,554,388 3490 - 5870 2 20,000

Lake Chad 2,497,738 1400 - 1450 (Chari River) 8 1,200

Lena 2,306,743 4270 - 4400 1 18,900

Niger 2,261,741 4030 - 4200 10 6,100

Amur 1,929,955 2820 - 5780 3 10,900

Yangtze 1,722,193 5520 - 6300 1 29,460

Mackenzie 1,706,388 4240 - 4250 1 9,910

Volga 1,410,951 3350 - 3688 2 8,050

Zambezi 1,332,412 2650 - 3500 8 7,070

Tarim 1,152,448 2000 2 650

Nelson 1,093,141 2575 - 2600 2 2,830

Indus 1,081,718 2880 - 3180 4 –

Murray 1,050,116 2570 - 3750 1 –

St. Lawrence 1,049,636 3060 - 4000 2 10,800

Note: a Basin area was digitally derived from elevation data using a Geographic Information System, and areas may differ fromother published sources.

Sources: Basin area and number of countries sharing the basin from WRI (2000); river length from Gleick (1993); virgin meanannual discharge from Dynesius and Nilsson (1994) and Revenga et al. (2000).



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Table 3. Information for Some Selected Lakes of the World

Lake Surface Max. Mean Volume Drainage Major problems Name Area (km2) Depth (m) Depth (m) (km3) Area (km2) affecting the Lake

Africa

Chivero 25.3 – 9.5 0.25 2,230 SalinizationEutrophicationExotic Species

Tanganyika 32,000 1471 570 17,800 263,000 Eutrophication

Victoria 68,800 84 40 2,750 284,000 EutrophicationExotic Species

Asia

Aral 60,000 69 16 1,090 – Water level change(1960) (1960) (1960)

Baikal 31,500 1637 751 23,670 540,000 –

Biwa 674 104 41 27.5 3,174 EutrophicationExotic Species

Bhoj Wetland 37.5 11.7 3.4 0.121 371 Toxic pollutionEutrophication

Kinnerent 170 43 – – – Eutrophication

Laguna de Bay 948 20 2.0 2.16 3,820 Toxic pollutionEutrophication

Tai-hu 2,428 3.0 2.0 4.46 36,500 Toxic pollutionEutrophication

Toba – 529 485 – – Toxic pollutionEutrophication

Tonle sap 2,450- 12 – – – –12,000

Australasia

Corangamite 251.6 6.0 6.0 1.5 – Water level change

Europe

Balaton 596 12 3.2 1.9 – Eutrophication

Bodensee 539 252 90 48.5 – Eutrophication

Maggiore 212.5 370 176.5 37.5 – Eutrophication

Ohrid 358 289 164 58.6 – Toxic pollutionEutrophication

Orta 18.2 143 71 1.3 – Toxic pollutionAcidification

Peipsi 3,555 15.3 7.0 25.1 – Eutrophication

N. America

Champlain 1,130 123 22.8 25.8 – Eutrophication

Mono 158-223 45.7-56.7 15.2-22.9 2.8-5 – SalinizationWater level change

Ontario 19,000 245 86 1,634 75,872 EutrophicationExotic SpeciesToxic Pollution

Tahoe 501 505 313 156.8 841 Eutrophication

S. America

Titicaca 8,372 281 107 8.96 – Eutrophication

Tucurui 2,430 75 18.9 46 – SiltationEutrophication

Source: Jorgensen et al. 2001


measures for ecosystems and species. However,much effort and financial commitment would haveto be made to restore hydrological stations, thenumber of which has declined around the worldsince the mid-1980s.

1.5 EXTENT AND DISTRIBUTIONOF LAKES

Of the estimated 5-15 million lakes across the globe(Herdendorf 1982; WWDR 2003) there are about

10,000 lakes with a size over 1 km2, the majority ofwhich are young in geological terms (UNEP-WCMC 2000). Table 3 lists some of these togetherwith relevant statistics and threats affecting them.Only about 15-20 existing lakes in the world areknown to be far older than 1 million years(LakeNet 2003) (see Table 4).

A disproportional share of large lakes—witha surface area over 500 km2—is found in NorthAmerica, especially Canada, where glacial scouringcreated many depressions in which lakes have


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Table 4. Ancient Lakes of the World

Lake Name Countries Age (million years)

Eyre Australia 20-50

Maracaibo Venezuela > 36

Issyk-Kul Kyrgizstan 25

Baikal Russia 20

Tanganyika Burundi 20TanzaniaDem. Rep. of CongoZambia

Caspian Sea Azerbaijan > 5IranKazakhstanRussia

Aral Sea Kazakhstan > 5

Ohrid Albania > 5Macedonia

Hovsgol Russia 2-5

Prespa Albania > 5GreeceMacedonia

Victoria Kenya > 4?TanzaniaUganda

Titicaca Bolivia 3Peru

Malawi Malawi > 2MozambiqueTanzania

Lanao Philippines > 2

Biwa Japan 2

Tahoe United States 2

Source: Compiled by Duker and Borre (2001) based on various sources.


formed. Knowing the depth and water volume isimportant for the understanding of lake watermovement and potential productivity. However,the calculations of these require detailed knowledgeof the lake bottom and thus are often estimatedrather than measured. Lakes undergo seasonalchanges and are modified through tectonic eventsor volcanic activity, landslides and erosion or wind.Measurements or estimates of surface area, depthor water volume can therefore vary among differ-ent investigators (WRI et al. 1994).

The International Lake Environment Com-mittee (ILEC) maintains a database of over 500lakes worldwide, with some physiographic, biolog-ical and socio-economic information (Kurata 1994;ILEC 2002). In collaboration with UNEP and theJapan Environment Corporation, ILEC has under-taken a Survey of the State of the World Lakes whichhas resulted in the publication of five volumes(1988-1993) containing detailed data for 217 lakesin 73 countries. The data collected by ILEC high-light seven major problem areas that are widespreadamong lakes and reservoirs. These are: lowering ofthe water level; siltation; acidification; chemical con-tamination; eutrophication; salinization; and theintroduction of exotic species (Kira 1997; Jorgensenet al. 2001). The major limitation of ILEC’s data-base is that it is questionnaire-based and thus theinformation is largely descriptive, often incomplete,and is not regularly updated. Revisions and updateshave recently been completed for 25 lakes, based ondata as recent as the year 2000 (Ballatore pers.comm. 2002). However, due to the lack of a com-prehensive data set, the figures are not comparable.The main conclusion drawn by this study is thatmost of the 25 lakes suffer from declining waterquality, which is leading to a severe reduction intheir ability to satisfy human needs. Eutrophication,which is recognized as the most widespread prob-lem is also one of the most difficult to abate(Jorgensen et al. 2001).

The Global Lake Status Data Base (GLSDB)compiles information on lake-level and relativewater depth through historical time periods. This

database is used to document long-term changesin regional water budgets, and for the evaluationof climate models using lakes as indicators ofpalaeoclimatic changes at a continental to globalscale. The database is updated on a region-by-region basis (Harrison 2001).

In terms of geographic location and extent,UNEP-WCMC’s global map of wetlands includesseveral thousands of records classified as lakes orsalt pans, many of which have information on thename and a very brief description of the site.

Lake and pond boundaries are also mapped inanother geographically referenced database, theESRI ArcWorld database (1992). This mapped data-base with a resolution of 1:3,000,000 is slightlymore detailed than that of UNEP-WCMC, but thewater bodies are only differentiated by types, andnot by individual name or site description.

The location of large water bodies can also beidentified with coarse-scale satellite-based land-cover datasets, such as Global Land CoverCharacteristics Database (GLCCD 1998), a globaldataset at a resolution of 1:1,000,000, derived fromAdvanced Very High Resolution Radiometer(AVHRR) satellite data. The AVHRR provides 4- to6-band multispectral data from the NOAA polar-orbiting satellite series. There is fairly continuousglobal coverage since June 1979, with morning andafternoon acquisitions available. The resolution is1.1 km at nadir.


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In many parts of the world freshwater ecosystemsare being intensely modified and degraded byhuman activities. The rapid proliferation of dams,river and stream embankments, and the drainingof wetlands for flood control and agriculture,for example, have caused widespread loss of fresh-water habitats, especially waterfalls, rapids, ripar-ian floodplains and related wetlands. A summaryof global and regional extents of known inlandwetland habitat losses and degradation is providedby Spiers (1999).

Habitat loss has been accompanied by adecline and loss of freshwater species, to a pointwhere the biodiversity of freshwater ecosystems iscurrently in far worse condition than that of forest,grassland, or coastal ecosystems (WRI 2000).Habitat degradation, physical alteration throughdams and canals, water withdrawals, overharvest-ing, pollution, and the introduction of exotic speciesall contribute directly or indirectly to the decline infreshwater biodiversity. These pressures occur allover the world, although the particular effects ofthese stresses vary from watershed to watershed.Findings from a study carried out on freshwaterfishes show that habitat alteration and the introduc-tion of exotic species are the two main causes ofspecies extinction (Harrison and Stiassny 1999).The study attributed 71% of extinctions to habitatalteration, 54% to the introduction of exotic species,29% to over-harvesting, 26% to pollution, and therest to either hybridization, parasites and diseases,and intentional eradication (some extinctions mayhave had several causing factors and, therefore, per-centages do not add up to 100) (Harrison andStiassny 1999).

The combination of pressures on freshwatersystems has resulted in more than 20% of theworld’s freshwater fish species to become extinct,endangered, or threatened in recent decades(Moyle and Leidy 1992). This estimate is consid-ered too low by some authors (Bräutigam 1999).

In North America research shows that species arebeing lost at an “ever-accelerating rate” (Moyle andLeidy 1992). Future extinction rates are believed tobe five times higher for freshwater animals than forterrestrial species (Ricciardi and Rasmussen 1999).With population growth, industrialization, and theexpansion of irrigated agriculture, the demand forall water-related goods and services will continueto increase dramatically, thereby increasing pres-sures on freshwater species and habitats.

Direct threats to different species groups arediscussed in detail in Section 3: Review of InlandWater Species Richness, Distribution and Con-servation Status of this document. The remainderof this section focuses on overall threats to theintegrity of freshwater ecosystems at the global level.In particular it focuses on the level of modificationof river systems, the current and projected degreeof water scarcity, the impact of invasive species oninland water ecosystems, the condition of inlandwater fisheries, and the impacts of climate changeon inland waters. Habitat loss and water quality,some of the most important threats to freshwaterbiodiversity, are not discussed in detail because ofthe lack of comprehensive data at global scale.

2.1 MODIFICATION OFRIVER SYSTEMS

Rivers have been altered since historical times, butsuch modifications skyrocketed in the early to mid-1900s. Modifications include river embankmentsto improve navigation, drainage of wetlands forflood control and agriculture, construction of damsand irrigation channels, and the establishment ofinter-basin connections and water transfers. Thesechanges have improved transportation, providedflood control and hydropower, and boosted agri-cultural output by making more land and irriga-tion water available. At the same time, thesephysical changes in the hydrological cycle discon-


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2. CONDITION OF, AND THREATS TO, INLAND WATER ECOSYSTEMS3

3 This section is largely extracted from Revenga et al. 2000. Pilot Analysis of Global Ecosystem: Freshwater Systems, World ResourcesInstitute, Washington DC, USA, and has been adapted and edited for this paper in agreement with the CBD Secretariat and theRamsar Bureau.


nect rivers from their floodplains and wetlands andslow water velocity in riverine systems, convertingthem to a chain of connected reservoirs. This, inturn, impacts the migratory patterns of fish speciesand the composition of riparian habitats, opens uppaths for exotic species, changes coastal ecosystems,and contributes to an overall loss of freshwater bio-diversity and inland fishery resources (Revenga etal. 2000). Dams also affect the seasonal flow andsediment transport of rivers for an average of 160kilometers downstream. Some major water pro-jects, such as the Aswan High Dam in Egypt, havean effect that extends more than 1,000 kilometersdownstream (McAllister et al. 1997).

Humans have built large numbers of dams allover the world, most of them in the last 35 years.Today, there are more than 45,000 large dams(more than 15 meters high) in the world, 21,600 ofwhich are in China alone (ICOLD 1998; WCD2000). This storage capacity represents a 700%increase in the standing stock of water in river sys-tems compared to natural river channels since 1950(Vörösmarty et al. 1997a). Table 5 shows thedistribution of large dams by continent, based

on the 25,410 registered dams reported by theInternational Commission on Large Dams(ICOLD) and the storage capacity of large reser-voirs. Obviously, differences between sources areevident as Table 5 does not reflect the aforemen-tioned statistic for the proportion in China.

In terms of storage capacity, Asia and SouthAmerica have seen the biggest recent increase inthe number of reservoirs. In Asia, 78% of the totalreservoir volume was constructed in the lastdecade, and in South America almost 60% of allreservoirs have been built since the 1980s (Ava-kyan and Iakovleva 1998). The inventory of damsand reservoirs is incomplete for China and the for-mer Soviet Union, which, together with the UnitedStates, are the world’s top ranking countries interms of number of large dams (ICOLD 1998).Reservoirs with more than 0.5 km3 maximumstorage capacity intercept and trap an estimated30% of global suspended sediments (Vörösmartyet al.1997b).

River fragmentation, the interruption of ariver’s natural flow by dams, inter-basin transfers,or water withdrawal, is an indicator of the degree


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Table 5. Large Dams and Storage Capacity of Large Reservoirs by Continent

Storage Capacity Number of of Large Reservoirs*

Continent World Registered Dams Large Reservoirs* Total Volume (km3)

Number** Percent

Africa 1,265 5% 176 1,000

Asia 8,485 33.4% 815 1,980

Oceania 685 2.7% 89*** 95***

Europe 6,200 24.4% 576 645

North America 7,775 30.6% 915 1,692

Central and South America 1,005 3.97% 265 972

Total Registered Number 25,410** — — —

Estimated Total Number 41,413 — 2,836 6,385

* Large reservoirs are those with a total volume of 0.1 km3 or more. This is only a subset of the world’s reservoirs. A figure of47,655 is given for large dams by WCD (2000).** Total number of dams may not add up due to rounding. ICOLD reports a total of 25,410 registered dams.*** Includes only Australia and New Zealand.

Sources: Revenga et al. 2000 based on data from ICOLD (1998) and Avakyan and Iakovleva (1998).


of modification of rivers by humans (Ward andStanford 1989; Dynesius and Nilsson 1994). TheWRI, in collaboration with the University of Umeåin Sweden (Revenga et al. 2000), assessed thedegree of fragmentation of the main large rivers ofthe world, with the exception of areas in South Asiaand Oceania (see Map 2, Appendix A, page 118).The degree of fragmentation of rivers was dividedinto three categories: strongly affected systems,moderately affected and free flowing. Stronglyaffected rivers included those with less than onequarter of their main channel left without dams,where the largest tributary had at least one dam, aswell as rivers whose annual flow patterns hadchanged substantially. Unaffected rivers were thosewithout dams in the main channel of the river and,if tributaries had been dammed, river dischargehad declined or been contained in reservoirs by nomore than 2%.

The study showed that, of the 227 major riverbasins assessed, 37% were strongly affected byfragmentation and altered flows, 23% were mod-erately affected, and 40% were unaffected.Strongly or moderately fragmented systems werewidely distributed in all assessed regions. Riversystems with parts of their basins in arid areas orthat had internal drainage systems were stronglyaffected. The only remaining large free-flowingrivers in the world were found in the tundraregions of North America and Russia, and insmaller coastal basins in Africa and Latin America.It should be noted, however, that considerableparts of some of the large rivers in the tropics,such as the Amazon, the Orinoco, and the Congo,would be classified as unaffected rivers if an analy-sis at the sub-basin level was done. The YangtzeRiver in China, which was classified as moderatelyaffected, has become strongly affected since theThree Gorges dam was completed.

The demand and untapped potential for damsis still high in the developing world, particularly inAsia. As of 1998, there were 349 dams over 60meters high under construction around the world(IJHD 1998). The countries with the largest num-

ber of dams under construction were Turkey,China, Japan, Iraq, Iran, Greece, Romania, andSpain, as well as the Paraná basin in SouthAmerica. The river basins with the most large damsunder construction were the Yangtze in China, with38 dams under construction, the Tigris andEuphrates with 19, and the Danube with 11. In thefuture the increasing number of dam removals thatbecomes necessary will again strongly impact thehydrology and ecology of the affected rivers. In thelast 20 years, over 500 dams have been removedworldwide (Bledzki pers. comm. 2003). However,the ecological implications of removal, and appro-priate removal strategies, are not fully understood.

Direct impacts of dams on diadromous fishspecies such as salmon, are well documented.Indirect impact of flow alteration on fish speciesassemblages has also been documented for severalartificial reservoirs in Africa. The reservoirs in thesecatchments have replaced running water habitatssuch as rapids and waterfalls, resulting in the dis-appearance of fish species adapted to lotic systemsand the proliferation of other, in many cases exotic,species adapted to lentic systems. One example isthe dramatic decline in the population of two com-mercially important fish species in the ZambeziRiver, Labeo congoro and Labeo altivelis. These twocyprinid species were abundant and maintained ahealthy fishery before the dam was built and LakeKariba was formed in 1958. The construction ofthe dam blocked their spawning migration andinundated riparian wetlands that constituted theirpreferred habitat causing the decline in speciesabundance. In just a few years, from 1960 to 1967,the species composition of the catch shifted frombeing dominated by Labeo to containing practicallyno Labeo (Lévêque 1997). When Kariba dam wasbuilt, it was hoped that the formation of the lakewould result in a productive fishery. However, LakeKariba was so unproductive that the Zimbabweangovernment decided to introduce a “sardine”endemic to Lake Tanganyika in 1967-68. This sar-dine now accounts for over 80% of the commer-cial catch of the lake (Gréboval et al. 1994.)


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In West Africa, a sharp decline of Mormyridae(an elephant-nosed fish family of Osteogloss-iformes) was observed in Lakes Kainji and Volta,after the inundation of their preferred habitats asa result of dams. On the other hand, small pelagicfishes and the predators that feed on these becameadapted to the newly created reservoir environ-ments and gradually replaced the native fauna(Lévêque 1997). Cases of adverse impact on thestructure of riparian vegetation from dams,embankments and canals are also widely reported(Nilsson and Berggren 2000). In tropical Asia,changes in flooding patterns due to river modifi-cations have also affected riverine and wetland-dependent mammal populations, such asmarshland deer and the Asian rhino in Thailand,India, and China, as well as diadromous fish stocks,such as sturgeons in China (Dudgeon 2000).Similar cases have been reported for North andSouth America, including eight species ofsalmonids, seven species of sturgeons, and fivespecies of shads and herrings in North America;diadromous coporo (Prochilodus mariae) in west-ern Venezuela and Columbia; and Amazon riverdolphins in the Amazon basin (Pringle et al. 2000).

2.2 WATER SCARCITY

Humans withdraw about 4,000 km3 of water ayear, or about 20% of the world’s rivers’ base flow(the dry-weather flow or the amount of availablewater in rivers most of the time) (Shiklomanov1997). Between 1900 and 1995, water withdrawalsincreased by a factor of more than six, which ismore than twice the rate of population growth(WMO 1997). In river basins in arid or populousregions, the proportion can be much higher. Thishas implications for the species living in ordependent on freshwater systems, as well as forfuture human water supplies.

Many experts, governments, and internationalorganizations around the world predict that wateravailability will be one of the major challenges fac-ing human society in the 21st century and that the

lack of water will be one of the key factors limitingdevelopment (WMO 1997; WWDR 2003). Theagricultural sector, society’s major user of water,withdraws 70% of all water for irrigation (WMO1997). Decreased river flows and falling groundwater levels are common problems in irrigatedareas, mostly because of the few incentives to con-serve water and improve the efficiency of irrigationsystems (Wood et al. 2000). In most regionsaround the world with large-scale irrigationschemes, water is undervalued and usually sub-sidized, which reinforces the lack of incentives forits conservation and reduced consumption.

As populations grow, demand for food and,therefore, water for irrigation increases, placinghigher pressures on the water left in rivers andstreams. The Aral Sea represents one of the mostextreme cases in which water for irrigation hascaused severe and irreversible environmental degra-dation of an aquatic system. The volume of waterin the Aral basin has been reduced by 75% since1960, due, mainly, to large-scale upstream diversionsof the Amu Darya and Syr Darya river flow for irri-gation of close to seven million hectares of land(Postel 1999; UNESCO 2000). This loss of water,together with excessive chemicals from agriculturalrunoff, has caused a collapse of the Aral Sea fishingindustry, a loss of biodiversity and wildlife habitats,particularly the rich wetlands and deltas, and anincrease in human pulmonary and other diseasesin the area resulting from the toxic salts and pesti-cides in the exposed seabed that are being spread bydust storms (WMO 1997; Postel 1999). Eventhough the Aral Sea is the most commonly citedand one of the most extreme cases, there are manyother examples where diversion for agriculture hascaused a decline in species richness and a disappear-ance of valuable wetland habitats. In the majorityof cases, the most impacted people are poor resi-dents, who depend on freshwater resources not onlyfor drinking water but as a source of food supply,especially animal protein, and income.

A global analysis of water scarcity indicatesthat currently more than 40% of the world’s pop-


20


ulation lives in water-scarce river basins (Revengaet al. 2000) (see Map 3a, Appendix A, page 119).Water experts define areas where per capita watersupply drops below 1,700 m3/year as experienc-ing “water stress”—a situation in which disrup-tive water shortages can frequently occur(Falkenmark and Widstrand 1992; Hinrichsen etal. 1998). In areas where annual water suppliesdrop below 1,000 m3 per person per year, the con-sequences can be more severe and lead to prob-lems with food production and economicdevelopment unless the region is wealthy enoughto apply new technologies for water use, conser-vation, or reuse. With growing populations, waterscarcity is projected to increase significantly in thenext decades, affecting half of the world’s peopleby 2025 (see Map 3b in Appendix A, page 119). Ofthe basins in which the projected population isexpected to be higher than 10 million inhabitantsby 2025, Revenga et al. (2000) estimated that sixbasins, specifically the Volta, Farah, Nile, Tigrisand Euphrates, Narmada, and the Colorado Riverbasin, will go from having more than 1,700 m3 toless than 1,700 m3 of water per capita per year.Another 29 basins will descend further intoscarcity by 2025, including the Jubba, Godavari,Indus, Tapti, Syr Darya, Orange, Limpopo, HuangHe, Seine, Balsas, and the Rio Grande.

While water demand is increasing, pollutionfrom industry, urban centres, and agricultural run-off is limiting the amount of water available fordomestic use and food production. In developingcountries, an estimated 90% of wastewater is dis-charged directly into rivers and streams withoutprior treatment (WMO 1997). In many parts ofthe world, rivers and lakes have been so pollutedthat their water is unfit even for industrial uses(WMO 1997). Threats of water quality degrada-tion are most severe in areas where water is scarcebecause the dilution effect is inversely related to theamount of water in circulation.

Widespread depletion and pollution alsoextends to groundwater sources, which accountfor about 20% of global water withdrawals

(Shiklomanov 1997). However, information of thecondition and even location of groundwateraquifers is very limited. Although there are nocomplete figures on groundwater use by the ruralpopulation, many countries are increasinglydependent on this resource for both domestic andagricultural use (Foster et al. 2000). Because muchof the groundwater comes from shallower aquifersthat draw from the same global runoff that feedsfreshwater ecosystems, overdrafting of groundwatersources can rob streams and rivers of a significantfraction of their flow. In the same way, pollution ofaquifers by nitrates, pesticides, and industrialchemicals often affects water quality in adjacentfreshwater ecosystems.

Distribution of irrigated agricultural systemssignificantly influences the current and future waterresource use pattern. However, detailed informa-tion on the irrigated areas and the intensity ofwater use in these areas are not available globally(Wood et al. 2000).

2.3 INVASIVE ALIEN SPECIES

The introduction of exotic species is the second-leading cause, after habitat degradation, of speciesextinction in freshwater systems (Hill et al. 1997).Exotic species affect native faunas through preda-tion, competition, disruption of food webs, and theintroduction of diseases. The spread of exoticspecies is a global phenomenon, which is increas-ing with the spread of aquaculture, shipping, andglobal commerce. The species introduced eitherintentionally or accidentally include a variety oftaxa from fish and higher plants (such as waterhyacinth) to invertebrates and microscopic plants(such as dinoflagellates). Worldwide, two thirdsof the freshwater species introduced into thetropics and more than 50% of those introducedto temperate regions have become established(Welcomme 1988).

Although the problem of exotic species isglobal in scope, no comprehensive information ontheir distribution and their effects on biodiversity


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and ecosystem condition are available at the globalor regional levels.4 Therefore, this report focuses onsome of the better-documented cases.

2.3.1 Fish Introductions

Exotic fish introductions are common in mostparts of the world, and they are an increasinglyimportant component of aquaculture (FAO1999a). Introductions are usually done to enhancefood production and recreational fisheries, or tocontrol pests such as mosquitoes and aquaticweeds. Introduced fish, for example, account for96.2% of fish production in South America and84.7% in Oceania (Garibaldi and Bartley 1998).The 2,574 records of international fish introduc-tion found in FAO’s Database on Introductions ofAquatic Species (DIAS) comprise over 80% of thetotal records, which includes vertebrates, inverte-brates, and plants (FAO 1998).

Naturally, the introduction of exotic fish has itsecological costs. A survey of 31 studies of fish intro-ductions in Europe, North America, Australia, andNew Zealand found that in 77% of cases native fishpopulations were reduced or eliminated followingthe introduction of exotic fish. In 69% of cases thedecline followed the introduction of a single fishspecies, with salmonids responsible for the declineof native species in half of these cases (Ross 1991).In North America, there have been recorded extinc-tions of 27 species and 13 subspecies of fish in thepast 100 years. The introduction of alien species wasfound to be a contributing factor in 68% of theseextinctions, although in almost every case therewere multiple stresses, such as habitat alteration,chemical pollution, hybridization, and overharvest-ing (Miller et al. 1989).

A good review of literature on the effect ofcarp on freshwaters, including those of America,can be found in Zabrano et al. (2001). For Europethere is abundant evidence of the harmful impactof common carp on fresh-water ecosystems(Breukelaar et al. 1994, Carvalho and Moss, 1995).

Although with less details, the adverse impact ofintroduced species on the native fauna is also doc-umented for Africa, Asia and South America.

The introduction of exotic predators to LakeVictoria illustrates the profound and unpredictabletrade-offs that can occur when management deci-sions are made without regard to the possibleeffects on the ecosystem. Before the 1970s, LakeVictoria contained more than 350 species of fishin the cichlid family, of which 90% were endemic,representing one of the most diverse and uniqueassemblages of fish in the world (Kaufman 1992).Today, more than half of these species are eitherextinct or found only in very small populations(Witte et al. 1992). The collapse in the lake’s bio-diversity was caused primarily by the introductionof the Nile perch (Lates niloticus) and Nile tilapia(Oreochromis niloticus), which predated on andoutcompeted the cichlids for food. But other pres-sures factored in the collapse as well. Overfishingdepleted native fish stocks and provided the orig-inal motivation for introducing the Nile perch andtilapia in the early 1950s. Land-use changes in thewatershed led to increased release of pollutantsand silt into the lake, increasing nutrient load andcausing eutrophication. These changes resulted inmajor shifts in the lake’s fish populations. Cichlidsonce accounted for more than 80% of LakeVictoria’s fish biomass and provided much of thefish catch (Kaufman 1992). The most importantcatfish in the original fish fauna, Bagrus docmacand Clarias gariepinus, also declined after theintroduction of Nile perch (Lévêque 1997). Thefish biomass of the lake now consists mostly ofonly three species: Nile perch (60%), Nile tilapia(2.5%), and native small pelagic Rastrineobolaargentea (35%) (Rabuor and Polovina 1995).Similar impacts have been reported for Lake Kyogain Uganda (Lévêque 1997).

There have been three types of major fishintroductions to tropical Asia and America over thelast 150 years: piscivorous sport fishes such as troutand bass, and carps and tilapias for enhancing food


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4 Note: a separate analysis of the impacts of invasive species on inland water ecosystems is in preparation for the CBD.


fisheries. Temperate piscivores and carnivores seemto have had the most reported negative impacts onindigenous fish fauna. Destructive impacts arerecorded from Cuban freshwaters, Lake Titicaca(Peru, Bolivia), and Lake Atitlan (Guatemala). In areview of introductions in tropical Asia andAmerica, on the other hand, introduced fishes werefound not to have caused severe damage to indige-nous species except for some incidents in LatinAmerica where piscivores were used (Fernando1991). In recent decades, tilapias have establishedand become a substantial contributor to inlandfisheries in Mexico, the Dominican Republic,Northeast Brazil, and Cuba (as much as 90% of thecatch) (Fernando 1991). Although this does notnecessarily mean that the native fish stocks havecollapsed it indicates a significant shift in the com-position and structure of biological communitiesin those systems.

In tropical Asia, herbivores and omnivores,such as Indian, Chinese, and common carps,comprise the majority of introductions. Exceptfor China, these temperate species of carps havenot contributed much to fishery yield in thetropics. In comparison, tilapias have boosted cap-ture fishery in Sri Lanka and Thailand, and aqua-culture in Philippines, Taiwan, and Indonesia(Fernando 1991).

In China, the world’s largest producer ofinland fish, Black carp (Mylopharyngodon piceus),Silver carp (Hypophthalmichthys molitrix), bighead(Aristichthys nobilis), and Grass carp (Cteno-pharyngodon idella), which have been introducedfrom their native ranges to other regions in China,are widely distributed and contribute significantlyto fisheries production. Although research on theimpact of introduced species on the native aquaticecosystems of China is limited, a few well-docu-mented cases exist. For example, Dianchi Lake inYunnan Province, where each river or lake systemhas a distinct fish species composition and containsa high number of endemics, the number of nativefish species declined after the introduction of over30 alien species in the early 1970s. Likewise, the fish

community structure of Donghu Lake, HunanProvince, has completely changed from a diversespecies assemblage to a system dominated by afew species after the introduction of aquaculture(Xie et al. 2001).

2.3.2 Water Hyacinth

Water hyacinth (Eichhornia crassipes) is anotherexample of an alien species that becomes invasivein many tropical and sub-tropical inland waterscausing considerable economic and ecologicaldamage in numerous aquatic systems around theworld. This plant, believed to be indigenous tothe upper reaches of the Amazon basin, wasspread throughout much of the planet for use asan ornamental beginning in the mid-19th century(Gopal 1987). By 1900 it had spread to every con-tinent except Europe and has now a pan-tropicaldistribution. The plant quickly extended its rangethroughout rivers and lakes in the tropics, cloggingwaterways and infrastructure, reducing light andoxygen in freshwater systems, and causing changesin water chemistry and species assemblages (Hillet al. 1997).

In recent years, water hyacinth has spread veryrapidly in Africa, from the Nile Delta and theCongo basin to regions in West Africa (particularlyCote d’Ivoire, Benin, and Nigeria), the equatorialzone of East Africa, and to the southern part of thecontinent, specifically Zambia, Zimbabwe, Mozam-bique, and South Africa (Harley et al. 1997). Inmany of the freshwater bodies in affected parts ofAfrica, water hyacinth control and eradication hasbecome one of the top priorities for environmentalagencies and fisheries departments. The presenceand rapid proliferation of this weed causes severedamage to fisheries, infrastructure, and navigation.

In Australia, water hyacinth has spread alongthe entire coast, although its impact is beingreduced by biological control. It has also spreadto many Pacific Islands, including New Zealand.In Papua New Guinea, water hyacinth has beenconfirmed in almost 100 locations with the most


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serious infestation reported for the Sepik River,where it has had “devastating effects on socioeco-nomic structure and on the environment” (Harleyet al. 1997).

In South America, its native range, waterhyacinth is found in the majority of the Amazontributaries, as well as in Guyana, Surinam,Argentina, Paraguay, Uruguay, the northern part ofColombia, Venezuela, and the central rivers inChile. It is also found in most of Central Americaand the Caribbean islands (Gopal 1987; Harley etal. 1997). Water hyacinth has become a pest inGuyana and Surinam and has spread into adjacentregions, creating problems in rivers and reservoirsby clogging dams and intake valves in Argentina,Bolivia, Cuba, and Mexico (Harley et al. 1997).

In Asia, it has widely spread through theSoutheast and India. In Europe, however, it hasbeen reported only in Portugal (Gopal 1987).

Unfortunately, despite the many problemsassociated with the water hyacinth, comprehensiveglobal studies quantifying its distribution, itsimpact on biodiversity, and its socioeconomicparameters within freshwater systems and ruralriparian communities are lacking. However, socio-economic impacts are known to be very great. Forexample, at its peak of infestation in an area ofsouthern Benin with a total population of 200,000people, annual yearly loss of income (chiefly fromfishing and food crops) caused by spread of waterhyacinth has been estimated as US$84 million (DeGroote et al. 2003).

2.4 FISHERIES EXPLOITATION

Inland fisheries from rivers, lakes, and other wet-lands are a major source of protein for a large partof the world’s population, particularly the poor. Incontrast to marine fisheries, where part of the catchis discarded or converted to fishmeal for animalfeed, in inland fisheries almost the entire catch isdirectly consumed by people—there is hardly anybycatch or “trash” fish (FAO 1999a). The popula-tion of Cambodia, for example, obtains about 60%

of its total animal protein from the fisheryresources of the Tonle Sap alone (MRC 1997). Insome landlocked countries, this percentage is evenhigher. Inland fisheries in Malawi provide about70-75% of the total animal protein for both urbanand rural low-income families (FAO 1996).

In 1997 the catch from inland fisheries totaled7.7 million metric tonnes, or nearly 12% of all fishdirectly consumed by humans from all inland andmarine capture fisheries (FAO 1999b). Inland fish-eries landings are comprised mostly of fish,although molluscs, crustaceans, amphibia, someaquatic reptiles and many other miscellaneousspecies also are caught and are of regional and localimportance (FAO 1999b). The catch from inlandfisheries is believed to be greatly underreported byfactor of two or three (FAO 1999a). Asia and Africaare the two leading regions in inland capture fishproduction. China is, by far, the most importantinland capture fisheries producer, accounting fornearly 28% of the global total in 1999 (2.3 milliontonnes), followed by India (8.3%) and Bangladesh(7.1%) (Kapetsky 2001).

According to the FAO, most inland capturefisheries that depend on natural production arebeing exploited at or above their maximum sus-tainable yields (FAO 1999a). Globally, inland fish-eries landings increased at 2% per year from 1984to 1997, although in Asia the rate has been muchhigher: 7% per year since 1992. This increase ispartially a result of efforts to raise productionabove natural levels through fisheries enhance-ments and of eutrophication of inland watersfrom agriculture run-off and certain types ofindustrial effluents (FAO 1999a; Kapetsky, per-sonal communication, 1999). China’s inland fish-eries production, for example, is much larger thanwould be expected given the available freshwaterarea it has compared to other regions of theworld. This fact as well as the large number ofreservoirs in the country, points to the strong useof fishery enhancements, such as stocking andaquaculture, to increase yields (FAO 1999a).These enhancements, however, can seriously affect


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the condition and long-term functioning of fresh-water ecosystems.

Freshwater aquaculture with a total produc-tion estimated to be 17.7 million metric tonnes in1997 (FAO 1999a), is in large part responsible forthe high freshwater fisheries production in Asia,and most certainly in China. Most of China’sproduction is carp. However, many aquacultureoperations, depending on their design and man-agement, can and have contributed to habitatdegradation, pollution, introduction of exoticspecies, and the spread of diseases through theintroduction of pathogens (Naylor et al. 2000).

In Europe and North America, freshwater fishconsumption has decreased over time and recre-ational fishing is replacing inland food fisheries(FAO 1999a). Currently recreational catch is esti-mated at about 2 million metric tons per year (FAO1999a). A positive trend in recreational fishing isbeing observed in countries across all economiclevels (Kapetsky 2001). In recent years recreationalfisheries contributed 52,000 metric tons to domes-tic consumption in Eastern Europe and 113,000metric tons in Western Europe (Varadi 2001).

Recreational and food fisheries in many coun-tries are maintained by fishery enhancements, par-ticularly species introductions and stocking (FAO1999a). Enhancements to increase recreational fish-eries are more prevalent in North America, Europe,and Oceania, while enhancements to increase foodproduction are more prevalent in Asia, Africa, andSouth America (FAO 1999a).

Assessing the pressure on inland fisheries andthe consequences for inland water ecosystems isdifficult, partly because of the paucity of reliableand comprehensive data on fish landings andwatershed condition, and because of partial andincomplete reporting by countries. For instance,reporting of inland catch is rarely done at thespecies level. Despite the shortcomings, the FAOdatabase on inland fisheries statistics is the mostcomplete data set on fishery resources at the globallevel (see Section 5 on Data Gaps and InformationNeeds for further discussion on fisheries data.)

2.5 EFFECTS OF CLIMATE CHANGE

This section provides a summary of the impactsof climate change on wetlands based on anInformation Paper “Climate Change and Wetlands:Impacts, Adaptation and Mitigation” prepared forRamsar’s 8th meeting of the Conference of theContracting Parties (COP8-DOC.11). This docu-ment provides an in-depth review of the potentialimpacts of climate change to inland waters by geo-graphic region. The overall impacts on wetlandsfrom climate change are summarized in Table 6.

Climate change can directly or indirectly affectmany ecosystem functions and thus the goods andservices they can provide. Wetlands are no excep-tion. The Intergovernmental Panel on ClimateChange (IPCC) defines habitats and ecosystemsvulnerable to climate change as “those that are nat-urally sensitive to climate change because of theirgeographical location or biophysical characteristicsor those that have few or no adaptation options toreduce the impacts of climate change” (IPCC2001b). Because most wetlands lack adaptationoptions many can be considered to be vulnerableto climate change. Particularly vulnerable wetlandsare those at high latitudes and altitudes, e.g., Arcticand Sub-Arctic bog communities, or alpine streamsand lakes (Gitay et al. 2001). Wetlands that are iso-lated are also considered to be vulnerable, prima-rily because if they experience species loss, thechance of recolonisation by species would be verylow (Pittock et al. 2001).

The assessment of the IPCC has documenteda series of changes in the planet’s characteristics asa consequence of a warming climate (IPCC 2001a).These changes occur as a result of internal variabil-ity of the climate system as well as both natural andhuman-induced external factors. Some of theseobserved and documented changes include anincrease in global surface temperature (0.4 to0.8 C); an increase in precipitation in many partsof the northern hemisphere; an increase in heavyand extreme precipitation events over land in themid- and high latitudes; an increase in the inten-


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sity and frequency of El-Niño events that can affectdrought and/or floods in many parts of the south-ern hemisphere; and a decline in Arctic sea-iceextent, particularly in spring and summer withabout a 40% decrease in the average thickness ofsummer Arctic sea ice over the last three decadesof the 20th century (IPCC 2001c).

The IPCC has also made some projections offuture changes in CO2 concentrations, tempera-ture, precipitation, and sea-level rise based on sev-eral new greenhouse gas emission scenarios that arebased on narrative storylines. All the scenarios areplausible and internally consistent, but have notbeen assigned probabilities of occurrence. Eachscenario has its own greenhouse gas emission tra-jectories and combines different degrees of demo-graphic change, social and economic development,and broad economic developments.

The impacts of climate change on wetlandswill come from “alterations in hydrologicalregimes, including the frequency and severity ofextreme events; increased temperature and alteredevapotranspiration rates, altered biogeochemistry,etc. (IPCC 1998; Burkett and Kusler 2000;USGCRP 2000).” The report provides a summaryof the projected impacts, which are replicated inTable 6.

The major impacts to inland waters describedby the IPCC include warming of rivers, which inturn can affect chemical and biological processes,reduce the amount of ice cover, reduce the amountof dissolved oxygen in deep waters, alter the mix-ing regimes, and affect the growth rates, reproduc-tion and distribution of organisms and species(Gitay et al. 2001). Species in small rivers and lakesare thought to be more susceptible to changes intemperature and precipitation than those in largerivers and lakes.

Predictions forecast that fish species distribu-tion will move towards the poles, with cold waterfish being further restricted in their range, and cooland warm water fish expanding in range. Aquaticinsects, on the other hand will be less likelyrestricted given their aerial life stages. Less mobile

aquatic species, such as some fish and molluscs, arepredicted to be more at risk because of their pre-sumed inability to keep pace with the rate ofchange in freshwater habitats (Gitay et al. 2001).

It is also predicted that with warmer weatherconditions, the establishment of invasive specieswill be facilitated. At high latitudes warming isexpected to increase biological productivitywhereas at low latitudes the boundaries betweencold and cool-water species may change and pos-sibly lead to extinctions (IPCC 1996). The effectsof climate change on nutrient cycling and waterquality are uncertain, although it is apparent thatthey will be influenced (van Dam et al. 2002).

Sea level rise may affect a range of freshwaterwetlands in low-lying regions of the world. Forexample, in tropical regions, low lying floodplainsand associated swamps could be displaced by saltwater habitats due to the combined actions of sealevel rise, more intense monsoonal rains, and largertidal/storm surges (Bayliss et al. 1997 as cited inRamsar COP8-DOC 11). Such changes will resultin dislocation if not displacement of many wetlandplant and animal species. Plant species not tolerantto increased salinity or inundation could be elimi-nated whilst salt-tolerant mangrove species couldexpand from nearby coastal habitats. Migratory andresident animals, such as birds and fish, may loseimportantresting, feeding and breeding grounds.

Climate change may also affect the wetlandcarbon sink, although the direction of the effect isuncertain due to the number of climate-relatedcontributing factors and the range of possibleresponses. Any major change to the hydrology andvegetative community of a wetland will have thepotential to affect the carbon sink. The impact ofwater level draw-down in northern latitude peat-lands has been well studied and is thought to pro-vide some insight for climate change impacts.Vegetation changes associated with the water draw-down in northern latitudes, for example, resultedin increased primary production, biomass, andslower decomposition of litter, which made the netcarbon accumulation rate to remain unchanged or


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even increase. However, other aspects of climatechange, such as longer and more frequentdroughts, and thawing of permafrost will mostlikely have negative effects on the peat carbon bal-ance. In addition, human activities, such as agricul-ture and forestry will also continue to transformwetlands and reduce overall wetland area, poten-tially resulting in losses of stored carbon.

Finally, the combined effect of climate changeand human-induced alterations to freshwater

systems has not been studied in detail. It may beexpected that changes in available water supplymay lead to the construction of more dams andcanals, which in turn will impact the habitats andspecies in those systems.

The extent of biodiversity loss or dislocationfrom inland water habitats will be difficult to dis-cern from other existing pressures. However, it canbe assumed that large-scale changes to these habi-tats will result in changes of species composition.


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Table 6. Projected Impacts in Some Key Wetland Systems and Water Resources underTemperature and Precipitation Changes (based on IPCC new emission scenarios andmodified in Ramsar COP8-DOC.11, from IPCC 2001c)

Indicators 2025 2100

Coastal wetlands and shorelines Loss of some coastal More extensive loss of coastalwetlands to sea level rise wetlands Increased erosion of shorelines Further erosion of shorelines

Ice environments Retreat of glaciers, decreased Extensive Arctic sea ice reduction,sea ice extent, thawing of benefiting shipping but harming some permafrost, longer ice wildlife (e.g. seals, polar bears,free seasons on rivers and lakes walrus)

Ground subsidence leading to changes in some ecosystems Substantial loss of ice volume fromglaciers, particularly tropical glaciers

Water supply Peak river flow shifts from Water supply decreased in many spring toward winter in basins water-stressed countries, increased where snowfall is an important in some other water-stressed source of water countries

Water quality Water quality degraded Water quality effects amplified by higher temperatures Water quality changes modified by changes in water flow volume Increase in salt-water intrusion into coastal aquifers due to sea level rise.

Water demand Water demand for irrigation Water demand effects amplified.will respond to changes in climate; higher temperatures will tend to increase demand

Floods and droughts Increased flood damage due to Flood damage several fold highermore intense precipitation events than “no climate change scenarios”Increased drought frequency Further increase in drought events

and their impacts

Source: Ramsar COP-8-DOC 11


Vegetation zones and species will change inresponse to temperature and inundation patterns,however, the extent of such change is unknown.White et al. (1999) predict that boreal forests inAsia will extend northwards into the tundra, andalso southwards. Similarly, fish migrations will beaffected by both temperature and flow patterns.

The most apparent faunal changes will possi-bly occur with migratory and nomadic bird speciesthat use a network of wetland habitats across orwithin continents. The cross-continental migrationof many birds is at risk of being disrupted bychanges in habitats (see references in Walther et al.2002). Further, disruption of rainfall and floodingpatterns across large areas of arid land willadversely affect bird species that rely on a networkof wetlands and lakes that are alternately or evenepisodically wet and fresh or dry and saline(Roshier et al. 2001) such as those used by thebanded stilt (Cladorhynchus leucocephalus) whichbreeds opportunistically in Australia’s arid interior(Williams 1998). Responses to these climateinduced changes may also be affected by adapta-tion and mitigation actions that cause further frag-mentation of habitats or disruption or loss ofmigration corridors, or even, changes to otherbiota, such as increased exposure to predators bywading birds (Butler and Vennesland 2000).


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This section reviews the distribution, richness andconservation status of freshwater-dependent taxafrom aquatic plants and insects to higher taxasuch as birds and mammals. It does not covermicroorganisms.

3.1 AQUATIC PLANTS

The definition of aquatic plants or hydrophytes hasbeen debated for decades. In general, “all plantsthat tolerate or require flooding for a minimumduration of saturation/inundation are consideredwetland plants” (Gopal and Junk 2000). An aquaticplant can usually be found growing in associationwith standing water including ponds, shallow lakes,marshes, ditches, reservoirs, swamps, bogs, canals,and sewage lagoons. Less frequently, they occur inthe flowing water of streams, rivers, and springs(Hebert 2002). This section synthesizes informa-tion on plant taxa that includes a large number ofbetter-defined aquatic species, and does notattempt to establish a new definition for what con-stitutes an aquatic plant.

Aquatic macrophytes include angiosperms(flowering plants), pterophytes (pteridophytes, ferns),and bryophytes (mosses, hornworts, and liverworts).Gymnosperms (conifers, cycads, and their allies) donot have strictly aquatic representatives (Cook 1990),but include a number of tree species that toleratewaterlogged soil, such as Bald Cypress (Taxodiumdistichum) which often dominates swamps in thesouthern U.S. (USFWS 1996). Macroaglae, such assome green and brown algae which are also consid-ered aquatic macrophytes are not discussed here.

There are 87 families and 407 genera of aquaticvascular plants (Cook 1990). Of these it is estimated

that up to 2% (or 250 species) of pterophytes (fernsand allies) and 1% (or 2,500 species) of angiospermsare aquatic (Groombridge and Jenkins 1998).

The geographic patterns of aquatic vascularplant diversity have not been summarized globally,however, a significant amount of information existfor regions where some aquatic plants are consid-ered pests (University of Florida 2001). There arealso a few studies, with limited geographic scope,that identify conditions that correlate with higherspecies richness or abundance (Bornette et al. 1998;Crow 1993; Zedler 2000).

3.1.1 Angiospermae (flowering plants)

Among angiosperms, 396 genera in 78 families areknown to contain aquatic species (see Table 8). Atthe family level, 12% of dicotyledons and 35% ofmonocotyledons have aquatic species, indicatingthe widespread occurrence of aquatic species,especially in more advanced herbaceous groups(Cook 1990).

Families with a large number of aquatic speciesinclude: Alismataceae (water plantain), Araceae(arum family), Potamogetonaceae (pondweed), andCyperaceae (sedge family) (Hebert 2002).

Geographic patterns of species diversity inaquatic angiosperms have been examined, in com-parison to latitudinal distribution of terrestrialspecies diversity, using the information compiledfrom literature covering North and CentralAmerica (Crow 1993). There are some families thatshow highest diversity at tropical latitudes, includ-ing Podostemaceae (river weed), Hydrocharitaceae(frog-bits), Limnocharitaceae (water poppies),Mayacaceae (bogmoss), Xyridaceae (yellow-eyed


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3. REVIEW OF INLAND WATER SPECIES RICHNESS, DISTRIBUTIONAND CONSERVATION STATUS

Table 7. Number of Aquatic Families in Major Angiosperm Groups

Aquatic Non-aquatic Total

Dicotyledons 44 319 363

Monocotyledons 34 63 97

Total 78 382 460

Source: modified from Cook 1990.


grass), while Potamogetonaceae (pond weeds),Juncaginaceae (arrow grass), Sparganiaceae (bur-reed), Haloragaceae (water milfoil), and Elatinaceae(waterwort) show higher diversity in temperateregions. Crow concludes that in the case of aquaticangiosperms, the typical latitudinal gradient in ter-restrial species diversity does not apply.

The conservation status of aquatic angio-sperms has not been comprehensively assessed. The1997 Red List of Threatened Plants (Walter andGillett 1998) listed the percentage of threatenedspecies for over 300 families. Among them are a fewaquatic plant families: 10 out of 75 Alismataceaespecies are considered threatened; 280 out of 4000Cyperaceae; 1 out of 6 Ceratophyllaceae (waterlilies); 14 out of 100 Hydrocharitaceae; 3 out of 31Lemnaceae; 3 out of 10 Limnocharitaceae; and 4out of 50 species of Nymphaceae (water lilies) areconsidered threatened. Since then, the Red List cri-teria have been revised; however only a limitednumber of plants have been assessed with these cri-teria. The 2002 IUCN Red List only lists 4 speciesas critically endangered, endangered, or vulnerable:Achyranthes talbotii, Angraecopsis cryptantha,Ledermaniella keayi, and Saxicolella marginalis. Allof them are found in Cameroon (IUCN 2002).

3.1.2 Ferns

There are about 11,000 species of ferns and fernallies, of which about 75% occur in the tropics(Hebert 2002). Among the Pterophyta there are 11genera from 9 families that contain aquatic species,of which Azollaceae (mosquito fern), Marsiliaceae(pepperworts), and Salviniaceae (water ferns) areexclusively aquatic (Cook 1990).

3.1.3 Bryophytes

A conservative estimate is that bryophytes (mosses,hornworts, and liverworts) comprise a group of14,000-15,000 species, of which 8,000 are mosses,6,000 liverworts, and 200 hornworts (Hallingbäckand Hodgetts 2000). Among the three classes of

moss, peat mosses such as the order Sphagnales, areecologically important in bogs, where they formlarge, floating mats over water. Liverworts grow in avariety of moist environments, including swampsand bogs, with a few species being found floating orsubmerged in water (Hebert 2002). Truly aquaticliverworts can be found on the surface of eutrophiclakes, including at least 16 species of Riellaceae. Theseare characteristic of temporary waters of semi-aridregions (Groombridge and Jenkins 2000). Althoughbryophytes occur almost throughout the world, someareas are recognized as being particularly rich in thesespecies. The maximum diversity is found in highlyoceanic regions, where cool or temperate and con-sistently moist climate conditions persisted over geo-logical time (Groombridge 1992). Many of thebryophytes found in lowland aquatic environments,including pools and reservoirs, are rare and threat-ened, with a very restricted distribution. Importantareas of lowland bogs, for example, occur in Tierradel Fuego in Argentina, northern Scotland, andIreland (Hallingbäck and Hodgetts 2000).

There are 10 freshwater bryophytes listed inthe IUCN Red List (IUCN 2002) as criticallyendangered, endangered, or vulnerable. Theseinclude critically endangered species of tropicallowland riverine systems such as Fissidens hydro-pogon (Ecuador), Ochyraea tatrensis (Slovakia),Pinnatella limbata (India), and Thamnobryumangustifolium (U.K.).

3.2 FUNGI

There are over 100,000 species of described fungiand probably over 200,000 still to be described.Most fungi are terrestrial, but they can be found inwide range of habitats, including marine and fresh-water environments. There are four major groupsof fungi that contain aquatic species: Zygomycota(true fungi), Ascomycota (sac fungi), Basidiomycota(club fungi), and Deuteromycota (fungi imperfecti).Aquatic ascomycetes are predominantly found onsubmerged wood, but others are free floating orfound on sediments and algae (Hebert 2002).


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An overview on the diversity of freshwaterfungi is provided in Goh and Hyde (1996). Althoughconsidered to be a small fraction of all the existingspecies, over 600 species of freshwater fungi are cur-rently known, including close to 340 ascomycetes ofwhich 50 occur in the tropics. The rest are com-prised by 300 hyphomycetes species the majority ofwhich are found in cold and temperate regions.These estimates, however, are based on a limitednumber of detailed studies from North Queensland(Australia), one lake in Austria, Illinois (U.S.), andthe Lake District and Devon (U.K.). Recent studiesindicate that there are many more freshwater fungito be discovered in temperate and tropical regions.Freshwater hyphomycetes in particular are knownto have global distribution and many taxa are beingdiscovered at a rapid rate (Goh and Hyde 1996). Thetotal estimate of freshwater fungi species ranges from1,000 to 10,000 (Palmer et al. 1997).

Around 20% of all fungi form lichens, a sym-biotic association of a fungus and a photosyntheticorganism, and 40% of lichenized fungi belong tothe ascomycetes group, which produce spores insac-shaped cells (Purvis 2000). There are about25,000 lichen species known capable of living inextremely harsh environmental conditions. Thenumber of aquatic lichens is limited and they typ-ically live in the intertidal zone along seashores orin shallow streams (Hebert 2002).

No comprehensive global list of lichens exists(Purvis 2000). An Internet-based global checklistof lichens and lichenicolous fungi is currently beingcompiled, including more than 120 checklists forAfrica, South America, Australia and many coun-tries of Asia, North and Central America.Checklists of continental Africa and South Americawere scheduled to be available in 2002, completionof the global list is foreseen in 2003 (Feuerer 2002).

3.3 AQUATIC INSECTS

Insect orders that are entirely aquatic or includeaquatic species are: Odonata (dragonflies and dam-selflies), Plecoptera (stoneflies), Trichoptera (caddice

flies), Ephemeroptera (mayflies), Megaloptera (alder-flies, dobsonflies, fishflies), Coleoptera (beetles),Diptera (two-winged, or true flies), Collembola(springtails), Hemiptera (true bugs), and Neuroptera(spongillaflies) (Mandaville 1999). Almost all thesespecies can fly, so their distribution is not strictlyconfined to water bodies. For example, the distri-bution range of dragonflies goes beyond a riverbasin or aquatic area (Banarescu 1990). Althoughno major extinction crisis of aquatic insects hasbeen reported so far, many groups are threatenedby a number of factors. Physical alteration andhabitat destruction due to impoundments is con-sidered the greatest threat to rare aquatic insects,followed by water pollution and siltation that resultfrom loss of vegetative cover in areas surroundingthe water bodies. In some areas, the introduction ofalien fish species that act as predators is also con-sidered a major threat (Polhemus 1993).

The conservation status of aquatic insects hasnot been comprehensively assessed, except fordragonflies in some regions. The 2002 IUCN RedList reports 127 freshwater species of insects as crit-ically endangered, endangered, or vulnerable. Ofthese, 17 species are beetles, one species is a mayfly,2 are stone flies, and 107 are dragonflies. In addi-tion 15 species from the beetle, dragonfly, dam-selfly, mayfly, and caddisfly groups are consideredto have gone extinct. The number of threatenedinsect species represents a very small fraction of thetotal number of known aquatic insects. Manyspecies have not been assessed and many others arebelieved to face local extinctions. The British RedData Book, for example, lists 133 aquatic insecttaxa as rare, endangered, or vulnerable; while theU.S. Federal Register under the Endangered SpeciesAct lists 204 species as threatened (Polhemus 1993).

Except for certain well-studied regions, e.g.Europe (Illies, 1978), the implementation of exist-ing laws to protect aquatic insects is limited becauseof the lack of precise information on species ecol-ogy and distribution. The situation is even worsein the tropics, where assessing the level of threat toaquatic insects is complicated further by the num-


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bers of undescribed species and the absence ofcomprehensive surveys (Polhemus 1993). Access totaxonomic data and surveys is limited by the factthat these are often published in the local languageand for national reports.

3.3.1 Odonata (dragonfliesand damselflies)

The taxonomy of dragonflies and damselflies is rel-atively well known among the aquatic insects.Around 5,500 species are described globally, andendemism tends to correspond to topographyrather than river basin. More species remain to bediscovered especially in tropical South America andSoutheast Asia, and it is estimated that the totalnumber of species is over 9,000 (Moore 1997). Theorder Odonata has been widely considered as abiological indicator of environmental health, andeven an indicator of vascular plant richness (Nixonet al. 2001; Sahlén and Ekestubbe 2001).

Comprehensive checklists of dragonflies exist(Davies and Tobin 1984 and 1985; Tsuda 1991).Tsuda’s work also provides information on the dis-tribution range of the species. The most compre-hensive and current global list of all recognizedOdonata species, based on previously publishedchecklists and literature, includes over 5,500 species(Schorr et al. 2002a and 2002b). In addition thereare a number of other checklists and databases scat-tered across different geographic regions and taxo-nomical groups (International Odonata ResearchInstitute 2002). Systematic mapping of species dis-tribution range has been done in many countries,mostly in Europe, with varying degree of accuracy.However, the knowledge of tropical species is con-fined to anecdotal reports (Moore 1997).

Although some sampling bias exists, generalareas of high diversity can be identified. Based oncountry-level species lists, tropical countries sup-port the highest biodiversity of dragonflies. Thewestern Amazon Basin and Southeast Asia are, asin so many other species groups, the regions ofhighest odonate diversity. Mexico, Central America,

and the large islands of Indonesia and Malaysiaalso support high diversity, while northernQueensland and West Africa support moderatelyhigh levels of odonate diversity. The eastern UnitedStates is another region of relatively high odonatediversity, paralleling diversity in numerous otherfreshwater groups (Paulson pers. comm. 2002). Inaddition to these species-rich areas, main centresof endemism include Madagascar, the mountainsof Central Africa, the mountains of Myanmar, theRyukyu Islands of Japan, New Caledonia, andHawaii (Moore 1997).

Enough knowledge on species distribution toset conservation priorities exists in a few countriesin Europe and North America and in Japan andNew Zealand. The information on odonates inAustralia, India, and South Africa is fragmented(Moore 1997). On the other hand, there is littleinformation as to specific localities with prominentdiversity within the tropics. Among the few knownlocalities of high odonate diversity in the tropicsare southern Peru and the foothills of the Andes inEcuador and Peru. Poorly sampled or under-sam-pled areas are Colombia, Bolivia, large parts ofChina, and insular Southeast Asia (Paulson pers.comm. 2002).

Of the 107 threatened Odonata species listedin the IUCN Red List, 13 are classified as criticallyendangered, 55 as endangered, and 39 as vulnerableto extinction. In terms of the geographic distribu-tion of threatened odonates, 27 are reported inNorth America, 3 in the Caribbean, 20 in CentralAmerica, 2 in Brazil, 6 in Europe (incl. formerSoviet Union), 6 in West and Central Asia, 18 inJapan, 3 in North Africa, 19 in Sub-Saharan Africa,and 4 in Australia (IUCN 2002).

3.3.2 Coleoptera (beetles)

Of the more than one million described species ofinsect, at least one-third are beetles, making theColeoptera the most diverse order of living organ-isms. Only 10% of the 350,000 described species ofbeetles are aquatic. There are at least 14 families that


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are either entirely or partially aquatic (Mandaville1999). Of these, the Hydraenidae family (moss bee-tles) has 1,200 species, the Hydrophilidae (waterscavenger beetles) has 2,800 species, and theDytiscidae (predaceous diving beetles) have 3950species, and better known than other groups amongaquatic Coleoptera. World catalogs for these groupswere recently published (Hansen 1998 and 1999;Nilsson 2001 and 2002). Aquatic beetles are foundin a variety of habitats and exhibit diverse adapta-tions to environments including some that even tol-erate saline habitats.

Hydraenidae are found in matted vegetationalong streams or decaying moss near the shore andswampy places, and have predacious larval stages.Most species of Hydrophilidae are aquatic both asadult and larvae. Although adults are principallyscavengers, larvae feed on a variety of aquatic ani-mals. Members of the large group Dytiscidae arefound in ponds, lakes, and streams. Both adultsand lavae are predators, feeding on a variety ofaquatic animals including small fish (Borror andWhite 1970).

There are many more species to be identified,even within these better-known groups: for exam-ple, recent expeditions to China and New Guineafor the sampling of Dytiscidae species have pro-vided many new species, and South America isconsidered as having a great potantial for produc-ing many more. Modern taxonomical revision ofmost larger beetle genera in South America wouldbe required (Nilsson pers. comm. 2002).

The status of known species has not been com-prehensively assessed. The 17 threatened aquaticbeetles listed in the IUCN Red List are almostentirely Dytiscidae species in Europe (IUCN 2002).

3.3.3 Diptera (flies, mosquitoes,and midges)

The Diptera is one of the largest groups of organ-isms, estimated to contain about 200,000 speciesworldwide, 120,000 of which have been describedso far (Wiegmann and Yeates 1996). Approximately

10% of all dipteran species are aquatic in their egg,larval, and pupae stages. Aquatic dipterans repre-sent some of the best-known insect groups, becausemany species are particularly important as vectorsof human, plant, and livestock diseases. Diptera alsoplay an important role in aquatic environments,including as food for many predators. They are alsogood indicators of aquatic environmental condi-tions because, in comparison with other aquaticinsects, they are more widely distributed across arange of habitat types and conditions (Mason et al.1995). Some 32 families contain species whoselarvae are either aquatic or semiaquatic, includingChironomidae (midges), Culicidae (mosquitoes),Tipulidae (crane flies), Simuliidae (black flies), andChaoboridae (phantom midges) (Mandaville 1999).A global database of Diptera is currently beingdeveloped (Thompson 2000).

3.3.4 Ephemeroptera (mayflies)

Some aquatic fly groups (Plecoptera, Ephemero-ptera, Trichoptera, Megaloptera) are commonlyused as biological indicators of stream water qual-ity. These groups express relatively less tolerance todegradation in water quality, such as lowered dis-solved oxygen level (USEPA 2001; DeShon 1995).Due to the taxonomic difficulties, the ordersPlecoptera and Ephemeroptera are poorly sampled,particularly in the tropics although stone fly distri-bution is rather restricted to temperate zones andless diverse in the tropics (Miller pers. comm).

There are about 2,000 species of mayflies,most of them associated with running water.The taxonomy of the immature stages is poorlyknown because the naiads of many species havenot yet been associated with adult forms. The orderhas a cosmopolitan distribution but is absentfrom the Arctic and Antarctic. They are also absentfrom oceanic islands, with the exception of NewZealand (Mandaville 1999). The Ephemeroptera isa primitive order, with many families having wideranges and others having more restricted ones(Banarescu 1990). Checklists for known species are


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available for a number of countries (Epheme-roptera Galactica 2001).

3.3.5 Plecoptera (stoneflies)

There are about 1,718 species of stoneflies repre-senting 15 families. The taxonomy of this order,like that of the Ephemeroptera, is poorly knownbecause the naiads of many species have not beenassociated with adults. Most naiads are restrictedto lotic systems of relatively high oxygen concen-trations, but some species may be found along thewave-swept shores of large oligotrophic lakes.The high water-quality requirements of naiadsmake them effective biological indicators of envi-ronmental degradation (Mandaville 1999). ThePlecoptera are a rather primitive order of insects,with confined distribution to water bodies whichmakes them biogeographically very significant(Banarescu 1990). The threatened mayflies andstoneflies in the IUCN Red List are all reportedfrom Australia (IUCN 2002)

3.3.6 Trichoptera (caddis flies)

About 10,000 species of caddis flies have beendescribed, but it has been estimated that this groupmay contain as many as 50,000 species (Holzenthaland Blahnik 1997). Caddis flies have a global dis-tribution and inhabit a wide range of habitats fromcool to warm streams, permanent lakes andmarshes, and temporary ponds. Although the lar-vae are found in a wide range of aquatic habitats,the greatest diversity occurs in cool running waters.Among the families represented in both lotic andlentic habitats, the genera exhibiting more ances-tral characters tend to be found in cool streamswhereas those showing more derived characterstend to occur in warm, lentic waters (Mandaville1999). This group of species has a large range ofpollution tolerance (USEPA 2001). A searchableworld checklist exists and is maintained by a groupof scientists under the successive InternationalSymposia on Trichoptera (Trichoptera Checklist

Coordinating Committee 2002). The database lists951 records in the Afrotropical bioregion, 1,157 inthe Australasian, 1,248 in the eastern Palearctic,1,558 in the Nearctic, 2,121 in the Neotropicalrealm, 3,754 in the orient, and 1,807 in the westernPalearctic region.

3.3.7 Megaloptera (alderflies)

The Megaloptera consists of about 300 extantspecies worldwide. The larvae of all Megalopteraspecies are aquatic and attain the largest size of allaquatic insects. Although they occur throughoutmost of the world, except for much of Africa, alder-flies are very difficult to find in tropical climates andlife histories of species in temperate zone are betterknown (Contreras-Ramos 1997). They express gen-eral intolerance to pollution (USEPA 2001).

3.3.8 Heteroptera (bugs)

Among the order Hemiptera, the sub-orderHeteroptera, with a total 38,000 species, containsabout 3,200 species of hydrophilic insects, repre-senting 15 families worldwide. Hemipterans aregenerally found in lentic habitats or in backwateror pool areas of streams (Mandaville 1999).Common aquatic families include Corixidae (waterboatman), Notonectidae (backswimmers), Nepidae(water scorpions), Belostomatidae (giant waterbugs), and Naucoridae (creeping waterbugs) all ofwhich are primarily predaceous. Other groups thatare not aquatic in a strict sense but live on thewater surface include Gerridae (water striders) andVeriidae (ripple bugs) (Borror and White 1970).

3.4 WATER MITES

Species of Hydrachnidia are common in such lenticwaters as swamps, marshes, ponds, and the littoraland profundal zones of lakes. They are often asso-ciated with vegetation or with the top few millime-tres of substrate, but they can also lead a planktonicexistence. Water mites are common, too, in the ero-


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sional and depositional zones of rivers, and the air-water interface at the margins of various waterbodies. Some species are adapted to live in suchextreme environments as thermal springs, glacialmeltwater rivers, temporary pools, waterfalls, andin groundwater buried within gravel banks ofstreams (interstitial habitats). A few species caninhabit oceans and inland saline waters, althoughmost are limited to freshwater.

Water mites are among the most abundantand diverse benthic arthropods in many habitats.One square metre of substratum from littoral weedbeds in eutrophic lakes may contain as many as2,000 deutonymphs and adults representing up to75 species in 25 or more genera (Smith and Cook1991). Comparable samples from an equivalentarea of substratum in rocky riffles of streams oftenyield over 5,000 individuals of more than 50species in over 30 genera (including both benthicand hyporheic forms). Mites have coevolved withsome of the dominant insect groups in freshwaterecosystems, especially nematocerous Diptera, andinteract intimately with these insects at all stages oftheir life histories.

Species of water mites are specialized toexploit narrow ranges of physical and chemicalregimes, as well as the particular biologic attributesof the organisms they parasitize and prey upon.Preliminary studies of physicochemical and pollu-tion ecology of the relatively well-known fauna ofEurope have demonstrated that water mites areexcellent indicators of habitat quality. The resultsof these studies, along with observations in sam-pling a wide variety of habitats in North Americaand elsewhere, lead to the conclusion that watermite diversity is dramatically reduced in habitatsthat have been degraded by chemical pollution orphysical disturbance (Smith and Cook 1991).

3.5 FRESHWATER MOLLUSCS

Information on species diversity is fragmentary.There are a few global overviews of a particulartaxon, or freshwater habitat, as well as regional over-

views of a particular river or lake system (Cushinget al. 1995; Gopal et al. 2000; Mitsch 1994; Taub1984). However, these studies are largely descriptiveand focus on hydrographics or biomass, rather thanprovide information on where high species richnessand endemism actually occur, and how one regioncompares to another in terms of their species diver-sity. A significant amount of research is also devo-ted to identifying the conditions within eachecosystem that correlate with higher species diver-sity or abundance rather than identifying specificareas of high species diversity and abundance.(Bornette et al. 1998; Crow 1993; Dillon 2000;Milner et al. 2001; Miserendino 2001; Zedler 2000)

The following section (on molluscs) summa-rizes existing information on the relatively better-known taxa. Because of the lack of publishedglobal overviews, the descriptio relies heavily onexpert knowledge.

Molluscs are some of the most ancient ani-mals that inhabit the earth. Their appearance inprehistoric deposits dates from 500 million yearsago. During this historical period, molluscs haveundergone waves of extinctions, however, today therate of extinction affecting freshwater molluscs ismuch faster than previously experienced. The mainreasons for this rapid extinction rate is that mol-luscs are extremely vulnerable to habitat degrada-tion, over-exploitation, and predation by alienspecies, all pressures that currently and in recenthistory have affected freshwater ecosystems world-wide. More than half the freshwater molluscanfamilies in North American, for example, are cur-rently extinct or listed as endangered (Kay 1995).

Freshwater molluscs are an integral part of therich invertebrate phylum mollusca. Brusca andBrusca (1990) present 8 classes of molluscs, ofwhich only two Gastropoda and Bivalvia (or Pele-cypoda) contain freshwater species. The approxi-mate numbers of living species, including marine,terrestrial, and freshwater molluscs in these twoclasses, are 40,000 and 8,000 respectively. The esti-mated total number of molluscs ranges from 80,000to 135,000 species (Seddon 2000). There are around


35


6,000 known species of gastropods and bivalves thatlive in freshwater habitats. Freshwater bivalvesinclude animals such as clams and mussels, whilefreshwater gastropods include snails and slugs.

Freshwater molluscs are found all over theworld except for Polar Regions, high altitudes andsome remote islands. The global species inventoryis far from complete, with new species regularlyadded and described from all regions, includingthose more thoroughly studied like Europe, theU.S., Japan, and Australia (Hilton-Taylor 2000).The most well studied group is the freshwater mus-sels with more than 250 species and 47 generadescribed to date (Kay 1995). Some ancient lakescontain highly diverse and endemic freshwatermussel fauna. For example, it is estimated that LakeBiwa in Japan has 73% of the freshwater musselspecies of the country, of which 43% are endemic(Kay 1995). Other spectacular lakes for freshwatermussel endemism are Lake Baikal, Tanganyka andTiticaca (Bos 1979).

There are many lists on freshwater molluscs atnational and regional levels, such as those availableon the internet (e.g. http://species.enviroweb.org/omull.html; and http://www.worldwideconchol-ogy.com/DatabaseWindow.html). These databases,however, are not standardized or comparable;therefore an assessment of the current status andtrends of freshwater molluscs at the global level isdifficult. Existing lists are also biased towards ter-restrial and marine groups.

In terms of the distribution pattern of thisgroup, UNEP-WCMC identified “important areasfor freshwater biodiversity” based on existing infor-mation and expert consultation, and highlighted27 known areas of special importance for freshwa-ter mollusc diversity worldwide (Groombridge andJenkins 1998; CBD 2001). The identified areascomprise a variety of habitats from ancient lakes(Tanganyika, Victoria, Malawi, Biwa, Baikal, Ohrid,Titicaca), to lower river basins (Congo, Volta,Mekong, and La Plata), and springs and under-ground aquifers (e.g., in Australia, New Caledonia,the Balkans, western US, Florida, and Cuatro

Cienegas basin in Mexico). One characteristic ofmollusc diversity is that endemism at species leveltends to occur within a river basin and, as moredetailed data for the U.S. show, species diversitycorrelates highly with fish species diversity (Boganpers. comm. 2002)

Assessments of the status of known specieshave been conducted for a limited number of taxaand regions and the results provide an overview ofthe threats that this group of animals is facing. TheIUCN Red List lists 332 freshwater species of gas-tropods that are either critically endangered,endangered, or vulnerable, representing over 40%of all gastropods threatened (including terrestrialgroups) (IUCN 2002). Springs-inhabiting snails arethe most threatened with the numbers of endan-gered species increasing from 12 to 19% of allthreatened molluscs since the 1996 Red List assess-ment. Of the threatened gastropods, 111 specieswere reported from the U.S., 81 from Australia, 76from Sub-Saharan Africa, 53 from Europe, and 5from Central America. On the other hand, 88bivalves were listed under these categories withmost of them reported from North America(IUCN 2002).

The IUCN Red List also confirmed the extinc-tion of a large number of molluscan species in theeastern U.S. that were previously suspected extinctbut were placed under Critically Endangeredbecause of insufficient information. The change inthe Table 8 below, therefore, reflects an improve-ment in the quality of the data rather than a changein the conservation status of these groups.

The alarming rate of extinction of freshwatermolluscs in eastern North America deserves specialattention. According to the U.S. Federal Registerover 30% of freshwater bivalves and 9% of gas-tropods in the U.S. are threatened, endangered, orextinct (McAllister et al. 2000). Less than 25% ofthe present freshwater bivalves appear to have sta-ble populations. A number of these endangeredspecies are “functionally-extinct,” meaning thatindividuals of a species are surviving but not repro-ducing (Bogan 1993). The status of gastropods is


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much less known. Of 42 species of extinct gas-tropods in the U.S., 38 were reported from theMobile Bay Basin (Bogan 1997).

3.5.1 Bivalvia or Pelecypoda (bivalves)

The taxonomic nomenclature of bivalves is beingrevised as knowledge on the group improves, andthere is currently no scheme that is universallyagreed upon. Thus the number and categorizationof groups and species used in the descriptionsbelow should be treated with caution. There aretwo orders that contain most of the freshwaterspecies: Unionoida and Veneroida. The Unionoidaare known as pearly freshwater mussels and have 6representative families that are all restricted tofreshwater. The larvae of Unionoida have a para-sitic stage to fish, making them sensitive to distur-bances of the freshwater ecosystems. Without thehost fish the unionoid species is unable to completeits life cycle and faces extinction (Bogan 1993).There are about 165 recognized unionoid genera(Bogan 1993). Of the 6 families, the largest one isthe Unionidae, which, along with the Margari-tiferidae, are the best-known families with world-wide distribution (Dillon 2000). There are otherprimarily marine families that include somefresh/brackish water species, but they are poorlyknown and thus not discussed here.

The small Margaritiferidae family is consid-ered the most primitive of the group and has a hol-arctic but discontinuous distribution. There areseven recognized species, currently divided intotwo genera: Margaritifera and Cumberlandia.Species in the genus Margaritifera are found inEastern Canada and New England, Northern

Europe, Asia, Northwestern North America,Southern U.S. (Louisiana and Alabama), Amurbasin and Russian Maritime Territory, Kamchatka,Sakhalin rivers, and the Iberian Peninsula.

The Unionidae on the other hand is a largefamily with worldwide distribution. This group ismost diverse in eastern and central North America,and followed by China and Southeast Asia. Thegroup includes North America’s most abundant,interesting, and economically valuable shells.Because of their long association with activities ofleisure, livelihood, and trade, many have acquiredcolorful common names. There are about 90 cur-rently recognized genera in the Unionidae. TheNorth American fauna north of Mexico is com-posed of 278 species and 13 recognized subspeciesin 49 genera (Bogan pers. comm.). There are alsofour subfamilies with a total of 16 genera that arewholly distributed outside North America andfound in east and Southeast Asia, India, Afghan-istan, Europe, and Africa.

Historically, mussels were used as food bynative peoples. In the late nineteenth and earlytwentieth centuries harvesting for the purpose ofmaking buttons for clothing increased consider-ably. With the advent of plastics in the 1940s and50s, this industry came to an end, with the lastplant closing in the mid 1960s (Williams and Neves1995). Soon afterwards unionid mussels came tobe used as the nuclei in cultured pearls cultivatedin Japan, and it is now estimated that 95% of theworld’s round cultured pearls contain nuclei fromAmerican freshwater mussels. More recently, someof the freshwater mussels themselves have beenused for pearl production using modifications ofthe Japanese techniques.


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Table 8. Freshwater Molluscs in the IUCN Red List in 1996 and 2000

Extinct CR, EN, VU Data Deficient

1996 2000 1996 2000 1996 2000

Bivalves 12 34 117 96 4 6

Gastropods 14 57 340 340 104 90

Source: McAllister et al. 2000; Hilton-Taylor 2000.


The distribution of species belonging to theother four unionoid families are: Hyriidae—presently with a disjunct distribution in SouthAmerica, Australia, New Guinea, and New Zealand,with fossils are also known from North America;Mycetopodidae—found in tropical and partly tem-perate South America through Central America tothe central west coast of Mexico; Iridinidae (incl.Mutelidae)—found in tropical Africa and the Nilebasin; Etheriidae or river oysters—which includethree or four genera, distributed disjunctively intropical Africa including the Nile, northwesternMadagascar, in the Rio Magdalena drainage inColumbia, the headwaters of the Amazon and inParaguay, and in southern India, (Banarescu 1990;Bogan pers. comm. 2002).

The Hyriidae found in Australia and theNeotropics are less studied, while Mycetopodidaein the Neotropics and Ethiopian Etheriidae andMutelidae “remain rather obscure” (Dillon 2000).

North America, including the Rio Grande, byfar contains the richest freshwater bivalve diversity inthe world—5 Margaritiferidae and 292 Unionidae.Asia, China and South Asia have a high diversity ofunionacean mussels second only to east and centralNorth America. There are 38 species described forChina, and 54 for Pakistan, India, Sri Lanka,Bangladesh, and Myanmar combined. The freshwa-ter bivalves in Africa include 55 species in 4 families,28 Mutelidae, 26 Unionidae, 1 Etheriidae, and 1Margaritiferidae. In Australia there are 17 Hyriidae.Russia and Europe are not particularly species-richin unionaceans, with only 2 Margaritiferidae and 8Unionidae documented (Bogan 1993).

Another order of freshwater bivalves is theVeneroida with 3 families: Sphaeriidae, Corbi-culidae, and Dreissenidae. The first group is large,and commonly known as pill clams and fingernailclams. This is strictly a freshwater family withworldwide distribution, although all species andmost genera have restricted ranges. They inhabitponds, swamps, and creeks. Within this familythere are approximately 75 North Americanspecies, but they are also found in Europe, Asia,

Africa, and South America. The second group areknown as basket clams, and they are widespreadand of moderate size, often tinged or colored withviolet in their interior. There are 12 genera, includ-ing several from brackish waters mostly foundin Asia, although some have become invasive inNorth America, and can also be found in Africa,South and Central America, and Australia(Banarescu, 1990). Finally the third family, theDreissenidae, is a much less diverse group.Members of this family, including quagga musselsand zebra mussels, are found in both fresh andbrackish waters of the Atlantic coast, the Caspian,Black, and Aral Seas and the rivers draining intothem, as well as in the Tigris and Euphrates Basin.The notorious zebra mussel, Dreissena polymorphafrom the Ponto-Caspian and the Aral Sea basins, isnow found in North America and Europe where itis causing serious and expensive damage to nativespecies and infrastructure particularly in the GreatLakes region in North America.

3.5.2 Gastropoda (gastropods)

There are about 4,000 freshwater gastropod or snailspecies known worldwide, found in a variety ofhabitats including streams, ponds, marshes, andlakes. The knowledge on the geographic pattern ofgastropod diversity at the global scale is limited.The U.S., Australia, and Europe are the better-sam-pled regions but data are still fragmented.Southeast Asia and Latin America are poorly sam-pled, except for some valuable medicinal species(Seddon pers. comm. 2002).

North America contains 601 freshwater gas-tropods representing 14 families. Hydrobiidae is byfar the most diverse family in this region with 228species, followed by Pleuroceridae, 156 species. Thehighest diversity are recorded in Mobile Bay andOhio-Tennessee rivers, with 118 (110 endemic) and99 species, respectively.

Regional estimates are not available for the restof the world. In Asia, only a few localities have esti-mated numbers of total species. For example, only


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the lower 500 km of the Mekong river basin hasbeen well-studied, and so far over 120 species areknown—including 92 endemic species of Triculinaeand 19 endemic species of Stenothyridae. Muchwork is required for the rest of tropical Asia. Muchof the knowledge on molluscs in South America isstill at checklist stage, and more investigations areneeded especially at headwaters. Some estimates areavailable for Parana, Uruguay and La Plata, andLake Titicaca. The gastropod diversity in Africa isgenerally not as rich as that of North America orthe Mekong. However, East African lakes have rela-tively high gastropod diversity, especially LakeTanganyika with 68 species. Another area with richgastropod fauna is the Congo basin, with 96 speciesknown only downstream of Kinshasa. In Russia,Lake Baikal contains by far the highest richness andendemicity of gastropods, with 147 species of which114 are endemic (Seddon 2000).

Freshwater gastropods are classified into twosubclasses, the Prosobranchia or gilled gastropodsand the Pulmonata or lunged gastropods. Thereare 20 families of gilled gastropods and 7 familiesof lunged gastropods around the world (Man-daville 1999). The gilled gastropods are morenumerous in terms of families and species thanthe freshwater mussels and tend to occur in largeand ancient lakes in tropical regions (Banarescu1990; Mandaville 1999). Most of these gastropodfamilies have a worldwide distribution. For exam-ple, the family Neritidae, one of the most primi-tive within this group, is found primarily in freshand brackish water in the tropics. Living species ofthe family Viviparidae are found throughout theworld except South America and much ofOceania. Hydrobiidae is a large family with manygenera and species whose taxonomy is still muchdebated among experts. Hydrobiids have a world-wide distribution and are characterized by theirsmall to almost microscopic size. The Poma-tiopsidae family is more abundant, particularly inSoutheast and East Asia, but can also be found inIndia, North America, the upper Paraguay River,southern and western Australia, and southern

Africa. Finally, the Pleuroceridae family is restrictedto freshwater with a centre of diversity in easternNorth America. Other families with morerestricted ranges include:• Valvatidae: restricted to the northern hemi-

sphere, with southern limits at the MexicanPlateau, south of Sahara, northern India, andnorthern East Asia;

• Melanopsidae: with disjunct distribution con-fined to the eastern hemisphere;

• Bithyniidae: also restricted to the easternhemisphere and with a center of diversity inSoutheast Asia; and

• Thiaridae and Ampullariidae: which arestrictly freshwater species with ranges encom-passing the tropical and subtropical zones(Banarescu 1990; Dillon 2000).

The freshwater Pulmonata or lunged snails arebest developed in ponds and in small to moder-ate-sized eutrophic lakes. These animals are of rel-atively recent origin and found in temperateregions. The systematics of Pulmonata are betterknown than that of the Prosobranchia, due totheir parasitic importance (Banarescu 1990). Thereare four major freshwater families in this group theLymnaeidae with a worldwide distribution, thePlanorbidae, by far the largest family of aquaticpulmonates with also a global distribution, theAncylidae (limpets) also worldwide, and thePhysidae with a Holarctic distribution.

Gastropods can be used as an indicator ofwater quality. Considerable research has been doneon the ecological and physiological tolerances andrequirements of gastropods. Pulmonates tend to bemore tolerant to eutrophication than prosobranchsbecause pulmonates can rise to the surface toobtain oxygen when the dissolved oxygen supply isdepleted. Most physids are known to tolerateanoxia for a short period of time but they, like allgastropods, need water well saturated with oxygenfor the proper development of their eggs. Similarly,many prosobranchs, like some pleurocerids andviviparids, can tolerate near-anoxia, but only forshort periods of time (Mandaville 1999).


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3.6 FRESHWATER CRUSTACEANS

There are about 40,000 living crustacean species,of which 10,000 are estimated to occur in freshwa-ter sediment, with 8,000 of these described so far(Palmer et al. 1997). The orders that are almostentirely freshwater include: Anostraca or fairyshrimp and Cladocera or water fleas. Other ordersthat include freshwater species, although to a lesserdegree, are the Amphipoda or side swimmers, theCopepoda and Decapoda (prawns, crayfish andcrabs), and the Isopoda (Hebert 2002). Freshwatercrustaceans also inhabit subterranean habitatssuch as caves. These species are usually amphipodsand isopods that tend to have extremely restricteddistributions—a single species being usually con-fined to one spring, one cave, or one cenote, andtherefore are highly susceptible to extinction(Schotte pers. comm. 2002). IUCN reports 409freshwater crustacean species as critically endan-gered, endangered, or vulnerable, including 69Amphipoda, 8 Anomopoda, 25 Anostraca, 51Calanoida, 168 Decapoda, 18 Harpacticoida, and38 Isopoda (IUCN 2002). There are 8 recordedspecies that have gone extinct. With the exceptionof the United States, no other country or regionhas assessed the status of known inland watercrustaceans comprehensively.

3.6.1 Amphipoda

Of 7,000 known species, 24% or about 1,700amphipods species are known to occur in freshwa-ter environments (Bousfield cited in McAllister etal. 1997). Freshwater amphipods can be found in avariety of habitats from shallow, densely vegetatedareas, to deep sediments in lakes, sometimes at den-sities of 10,000 per square metre (Hebert 2002). Ingeneral, freshwater species are poorly sampled, andhuge data gaps exist for Africa, Southeast Asia, andSouth America except for Lake Titicaca. In addition,many islands remain unexplored, even most of theCaribbean (Gable pers. comm. 2002).

Some groups are better known than others asexemplified by a database of subterranean amphi-pod families. This database describes about 900species representing 35 families found in subter-ranean habitats, including many that are not fresh-water. In addition, over 5,000 specimen records ofsubterranean amphipods are currently beingentered into the database (Holsinger pers. comm.2002). For some better-sampled groups patterns ofdistribution are known. For example, type locali-ties for specimens of the family Bogidiellidae, whichoccur worldwide except for boreal, Arctic, andAntarctic regions, indicate an apparent concentra-tion in the Mediterranean region, and to a lesserextent in Central America, South America, and theCaribbean region (Holsinger 2000; Koenemannpers. comm. 2002). Sampling gaps exist in Africaand Central and Eastern Asia (particularly, theSiberian far east and central western China),Middle East, especially in groundwater aquifers indeserts and very dry regions, and some parts ofAustralia (Koenemann pers. comm. 2002; Hol-singer pers. comm. 2002).

3.6.2 Copepoda

Copepods are one of the largest groups of crus-taceans with over 14,000 species described to date.These represent as little as 15% of the total num-ber of species that actually exist. Copepods arefound in both marine and freshwater systems, butare much more diverse in marine environments(Hebert 2002). They are widely distributed fromfreshwater to hyper-saline conditions, from thehighest mountains to the deepest ocean trenches,and from the cold polar ice-water interface to thehot active hydrothermal vents.

The Smithsonian National Museum of NaturalHistory maintains an on-line bibliographic andspecimens database of copepod crustaceans con-taining over 5,000 records worldwide, includinginformation on type localities (Smithsonian 2002).However, the collection has few African species.European museums on the other hand have a much


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larger representation of specimens from Africa andthe Japanese and Australian museums have strongerAsian collections (Walter pers. comm. 2002). Theinformation from collections among differentmuseums would have to be synthesized to get abetter sense of copepod diversity worldwide.

3.6.3 Isopods

With approximately 10,000 described species, theorder Isopoda is the second most diverse group ofcrustaceans. About 850 freshwater species areknown worldwide. Freshwater isopods also knownas sowbugs or aquatic pill bugs are widely distrib-uted across freshwater habitats including lakes,rivers, streams, underground aquifers, thermalsprings, water held in some tropical plants, andcave habitats where they often display associatedspecializations (Brusca 1997). The actual ranges ofmost species are very small with a very high levelof endemism.

In general the freshwater isopod fauna hasbeen very poorly sampled worldwide. Distributionof type localities based on one of the best museumcollections indicates higher concentrations inWestern Europe and North America; however, thecurrent distribution data reflects collection biasrather than a true picture of biodiversity.

Spain, France, Italy, and the eastern U.S. havebeen well sampled for many years, with apparenthigh diversity in cave and subterranean habitats.South America seems to be very poorly sampledexcept for groups representing fish parasites.Many more species are likely to await discovery inMexico and the Balkans, areas rich in karst habi-tats, where isopods tend to have particularlyrestricted ranges. Scandinavia, Asia, western U.S,Canada, and Alaska are very poorly surveyed ingeneral, as are Africa and Madagascar except forsome subterranean species in northern Africa andalong the perimeter of the continent (Schottepers. comm. 2002).

The Smithsonian National Museum ofNatural History maintains an on-line bibliographic

and specimens database of isopod crustaceans con-taining 10,054 records worldwide, including infor-mation on type localities (Smithsonian 2002).

3.6.4 Decapods (prawns,crabs and crayfish)

Freshwater crabs and crayfish each have a circum-global distribution, but their distributions are forthe most part mutually exclusive. Freshwater crabsdominate tropical freshwaters while crayfishabound in temperate regions and although thereare some species found in the tropics and subtrop-ics they are much less prevalent in these latitudes(Cumberlidge pers. comm. 2002). Their distribu-tion range is generally not confined to one riverbasin (Banarescu 1990).

True freshwater crabs are restricted to thetropical and warm temperate zones of Central andSouth America, Southern Europe, Africa andMadagascar, South and Southeast Asia, China,Japan. The Philippines, New Guinea, and Australia.They are also found in the Gulf of Guinea islands,the Seychelles, Socotra, Sri Lanka, and parts of theWest Indies (Banarescu 1990). Freshwater crabs arenot found in the U.S., Canada, Northern Europeor Russia. They are also absent from oceanic islandsin the Atlantic and Pacific, including NewCaledonia, New Zealand, Tahiti, and Hawaii. Thereare at least 1,000 species worldwide, with high ten-dency towards endemism. Checklists of species canbe compiled for most of the range of this group.Gaps exist for Africa (other than West Africa), Indiaand Burma, and most of the Indonesian archipel-ago (Cumberlidge pers. comm. 2002).

A freshwater crab (Hymenosoma lacustris)confined to lakes in northern New Zealand isreported to have declined following the introduc-tions of salmonids for sport fishing (Fish 1966).

Crayfish generally occur in the freshwaterecosystems in the temperate parts of the world (i.e.,Canada, U.S., temperate South America, Europe,China, Korea, Japan, Australia and New Zealand).They are also found in the tropics and subtropics


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in Mexico, Cuba, Haiti, The Dominican Republic,Madagascar, New Guinea, New Caledonia andAustralia (Banarescu 1990; Cumberlidge pers.comm. 2002). There are almost 600 species world-wide, of which 400 are found in North America.Endemism at the species level is high, especially inthe Southeastern United States, Australia, Asia, andMadagascar. There are two centres of freshwatercrayfish diversity: southeastern U.S. and Victoria,Australia. A worldwide checklist of species is avail-able on-line (Crandall and Fetzner 2002).

Prawns are a very diverse group in freshwatersand include two major groupings—the Palae-monidae (including the important large riverprawns of the genus Macrobrachium) and thesmaller Caridinidae. Both form the basis of impor-tant fisheries in rivers, floodplains, ricefields andother wetlands of tropical regions and are veryimportant in food-webs. River prawns also formthe basis of very significant aquaculture globally.Despite this importance, freshwater prawns remainvery little studied and details of their biology andtaxonomy are fragmentary. Even less informationis available on their socio-economic value (exceptfor commercial aquaculture) although they arewidely acknowledged to be important.

Nineteen species of freshwater crustaceansbelonging to seven genera (Decapoda) are nowknown from Vanuatu (Marquet et al. 2002).In contrast to Fiji and New Caledonia whereendemics represented 12% and 35% of the totalrespectively, no endemics were found in Vanuatu,which can be explained by the relatively recent for-mation of this archipelago.

New Caledonia has 34 species of freshwatercrustaceans. The New Caledonian freshwater palae-monid fauna (Crustacea) totals ten species in twogenera, which is comparable to the 10 speciesrecorded from neighbouring Fiji. All but 1 NewCaledonian species, the only endemic (Macro-brachium caledonicum) are wide-ranging in theIndo-West Pacific. No large-egged, palaemonidshave so far been recorded from New Caledonia orfrom the other islands of Oceania. This contrasts

with the larger continental land mass of Australia,which has 4 of those species plus 1 undescribed(Short and Marquet 1998).

Atyid shrimps have also been surveyed in NewCaledonia, yielding 21 species of which ten areendemics. Diversity is higher on the wetter, wind-ward northeast coast. High endemism in thesouthern part suggests its early geologic isolation(Choy and Marquet 2002).

3.6.5 Cladocera

There are about 600 species of Cladocera, of whichthe genus Daphnia is mostly responsible for algaecontrol in reservoirs. The only Daphnia recordedfrom North America has been examined usingmolecular taxonomy.

3.7 ROTIFERA

There are over 2,000 species of Rotifers, which areresponsible for nitrate and phosphate recycling infreshwaters. Since they recycle nutrients faster thanbacteria they play an important part in the eutro-phication process. Rotifers are one of the most dif-ficult invertebrate groups to identify and one ofthe most neglected groups taxonomically. TheRotifera museum collections are fragmentary, lostor damaged.

3.8 FRESHWATER FISH

Most global and regional overviews of freshwaterbiodiversity include more information on diversityof fishes than any other freshwater group (Cushinget al. 1995; Gopal et al. 2000; Groombridge andJenkins 1998; Taub 1984). A number of otherregional overviews are devoted to the diversity offishes (e.g., Kottelat and Whitten 1996; Lévêque1997; Skelton 1994; Snoeks 2000; Stiassny 1996),yet there is still much to be discovered and manyof the existing overviews need regular updating—about 200 new fish species are being describedannually (Lundberg et al. 2000.)


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Of the 25,000 total living fish speciesdescribed worldwide, the vast majority belong tothe group Actinopterygii or ray-finned fish, ofwhich 41% or about 10,000 species, are primarilyfreshwater species, with an additional 160 speciesregularly migrating between fresh and salt waters.Fishes are a polyphyletic group—a group contain-ing an ancestor and all of its descendants—thus,both marine and freshwater fishes, are included inother taxonomic groups such as the Myxini orhagfishes, with 25 species, the Cephalaspido-morphi or lampreys, with 35 species, the Elas-mobranchii or sharks and rays, with 1,200 species,and the Sarcopterygii, which include 1 species ofcoelacanth and 7 species of lungfishes (Lundberget al. 2000).

In terms of species numbers and overall dis-tribution, the Otophysi (also known by their for-mer taxonomic name as Ostariophysi) dominatefreshwater fish diversity. This group includes thefollowing major orders: Cypriniformes (carps,minnows, barbs, suckers, loaches, with roughly2,700 species), Characiformes (tetras, piranhas,with at least 1,300 species), Gymnotiformes (elec-tric eels and knifefishes with over 90 species), andSiluriformes (catfishes, with over 1,400 species).

In terms of their geographic distribution pat-tern, it is estimated that Latin America has over5,000 species of freshwater fish, followed by tropi-cal Asia and Africa with over 3,000 species each,North America with 1,000 species, and Europe andAustralia with several hundred species each. Itshould be noted however, that there are major dif-ferences in the level of knowledge on inland fishfauna across different geographic regions.

With respect to their conservation status, it hasbeen estimated that, in recent decades, more than20% of the world’s 10,000 described freshwaterfish species have become extinct, threatened, orendangered (Moyle and Leidy 1992). This figure,however, is considered a major underestimate(Bräutigam 1999). According to the WRI’s latestecosystem assessment, freshwater ecosystems andtheir dependent species, particularly fish and inver-

tebrates are more severely degraded than forest,grassland, and coastal ecosystems (WRI 2000).

The IUCN Red List includes 627 freshwaterfish species classified as critically endangered,endangered, or vulnerable. These include 610Actinopterygii, 3 Cephalaspidomorphi, and 14Elasmobranchii (IUCN 2002). In all, over 80% ofthe total number of threatened fish species arefreshwater fish (Hilton-Taylor 2000). The percent-age is much higher if freshwater representatives ofmarine groups are included where they are underthreat from conditions in inland waters (e.g.,salmonids and sturgeons). Because in-depth assess-ments of the conservation status of freshwater fishhave been limited to a few countries, regional dis-tribution of threatened species is strongly biasedtowards these countries. This is why more threat-ened fish species have been found in North Americathan in other regions of the world. This also appliesto a lesser extent to threat status in Sub-SaharanAfrica, Central America, the Caribbean, Europe, andcertain areas in Southeast Asia.

To assess the validity of the threat status, andtest the potential existing biases, Harrison andStiassny (1999) assessed 245 freshwater fish speciesrepresenting 2% of the total known freshwater fishspecies worldwide, which were known to be“potentially extinct or seriously threatened.” Theassessment results concluded that the geographicand taxonomic representation of the speciesassessed is biased due to more exhaustive reviewsof species’ status in some countries and the lack ofinformation for other regions. Of the 245 speciesassessed, 132 or 54% were cichlids from LakeVictoria, while another seventy were non-cichlidspecies belonging to 10 taxonomic orders, withsalmoniformes and cyprinodontiforms represent-ing a larger percentage of “possible extinctions”than would be expected given the actual size ofthese taxa. Given these biases, the results ofHarrison and Stiassny’s study as well as those ofother threat assessments do not provide a cleargeographic pattern of possible fish species extinc-tions, but give an unambiguous indication of the


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steady increase in the number of possible extinc-tions over the last 50–100 years.

In South, Southeast, and East Asia combined,there are at least 3,500 freshwater fish species somewith very restricted ranges. The majority of thehigh-fish diversity countries are in the tropics, withIndonesia, India, Thailand, Vietnam, and Malaysialeading the list (Kottelat and Whitten 1996). Thedominant groups of fish in this tropical region are:cyprinids (carps and minnows, with close to 1,000species), loaches from two groups (Balitoridae andCobitidae) with about 400 species, Bagridae (bagridcatfishes, with 100 species), Perciformes (Osphro-nemidae or giant gouramies, with 85 species), andthe Gobiidae family with 300 species. A distinct fea-ture of fish fauna in tropical Asia is its diversity atfamily level—121 families have been recorded ininland waters, in comparison to 50 in Africa andabout 55 in Latin America (Lundberg et al. 2000).

Species diversity estimates for freshwater fishhave also been made by basin for some large riversystems of the world (Revenga et al. 1998). Theriver systems in Asia with the highest number offreshwater fish species include the Mekong Riverwith at least 1,200 species, followed by the YangtzeRiver in China and the Kapuas River in Indonesiawith close to 320 species each. The Xi Jiang or PearlRiver, and the Chao Phraya also have rich fishdiversity with over 200 species each; while the SongHong or Red River shared by Vietnam and China,the Huang He or Yellow River, the Indus, theSalween, and Ganges each have over 140 species offreshwater fish. These figures are indicative onlyand are invariably underestimates. River systems inthis region with high occurrence of endemicspecies are the Xi Jiang (with 43% of endemics),the Mekong, the Salween, and the Tigris andEuphrates (over 25%). Compared to river basins inSouth America and Africa, Asian river systems mayseem less species-rich. However, species richness isoften proportional to the size of the basin, and interms of the number of species per square kilome-ter of basin area, the Kapuas River ranks among thehighest in the world, followed by Chao Phrya.

When number of species is calculated relative tobasin area these two rivers have by far a higher den-sity of species richness than the Amazon or theCongo basins (McAllister 2000). These estimatesprovide an overview of the fish species diversity inthe region. However, there are significant differ-ences in ichthyological knowledge and nomencla-ture between regions and countries.

From research and literature review, it is clearthat much of the fish fauna of tropical Asia stillneeds to be explored and discovered. There areconsiderable data gaps and nomenclature differ-ences among the countries in the region, whichmakes access and harmonization of information achallenge. Some of the key countries with datagaps include India, Sri Lanka, Laos, Vietnam,Bhutan, Brunei, Myanmar, Cambodia, North andSouth Korea and remote areas of Indonesia. Inthese latter countries, problems with outdatednomenclature and poor sampling coverage, are themain causes for the information gap (Kottelat andWhitten 1996; Lundberg et al. 2000). In Bhutan,Brunei, Myanmar, Cambodia, Laos, North andSouth Korea, comparison of records of fish specieswith estimated species richness cited by Kottelatand Whitten (1996) indicate that only 30-60% ofthe fish fauna of these countries has beenrecorded. China, on the other hand has data hold-ings on fish species, but because of language andisolated ichthyological research, adequate compar-isons with other countries has been and continuesto pose a challenge.

A comprehensive assessment of the threatenedfishes in Asia does not exist. However, in Japan,where exceptionally good data exist, a 1995 assess-ment shows that 39 out of total 200 freshwater orbrackish fish species (about 20%) are rare, endan-gered, or vulnerable, and 2 species have goneextinct (Japanese Council of Ministers for GlobalEnvironmental Conservation 1995). Other esti-mates of the conservation status of fish are pro-vided by Moyle and Leidy (1992). For example inIran, 22% of fish species have severely decliningpopulations and 28% of Sri Lanka’s freshwater


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fishes are classified as endangered, threatened, or“of special concern.” China has 31 species listed asthreatened in the IUCN Red List, including manycyprinids and some sturgeons (IUCN 2002), whichis a small fraction of the total species that are foundin this large country. Indonesia and Philippines alsohave a significant number of threatened freshwa-ter fishes (57 and 26 species, respectively), reportedfrom relatively limited number of localities. Of the14 Elasmobranchii species, 7 are freshwaterstingrays and sharks found in South and mainlandSoutheast Asian rivers (IUCN 2002).

Africa is estimated to harbor some 2,850species, in 40-50 families, depending on the taxo-nomical convention followed. This number, prob-ably an underestimate because of information andknowledge gaps, is considered low for the size of thecontinent. However, the African ichthyofauna ishighly endemic—almost 100% at species level and40% at family level—and includes some extraordi-nary examples of evolutionary phenomena, rang-ing from “living fossils” to uniquely high speciationand adaptation rates (Lundberg et al. 2000).

More than two-thirds of African freshwater fishspecies belong to two common groups: Otophysifishes—Cyprinidae (475 species in 23 genera),characiforms (characins, with 208 species in 39 gen-era), and siluriforms (catfishes, with 3 families:Clariidae—74 species in 12 genera, Clariteidae—98species in 18 genera, and Mochokidae—167 speciesin 10 genera); and fishes from the Cichlidae familywith 870 species in 143 genera (Lundberg et al.2000.) Among these, Cyprinidae, Characidae, and afew siluriform families constitute the primary com-ponent of riverine fauna, along with Cyprino-dontiforms (killifishes, pupfishes) and Mormyridae(elephantfishes). On the other hand cichlids(Cichlidae) are by far the most abundant and thedominant group in lacustrine environments, partic-ularly East African Great Lakes (Lévêque 1997;Lundberg et al. 2000).

Within Africa, as in Asia, the highest fish speciesrichness is found in large river systems, includingtheir lakes and wetlands, in the tropical regions of

the continent. The freshwater systems with the high-est number of freshwater fish species are the Congobasin and Lake Tanganyika, with 700 species, LakeVictoria with 343 species, the Niger River with 164species, and the Volta with 141 species. The Congobasin contains the highest level of endemism (70%)among the major African rivers. Among the Africanlakes, Lake Victoria and Lake Tanganyika have thehighest levels of endemism (90 and 77% respec-tively). Other systems with high ratio of endemicsare: Lake Turkana (39%), Orange River (29%), andthe Zambezi and Senegal rivers with over 20%endemics (Revenga et al. 1998).

African fishes have been studied extensivelysince the colonial period—a series of checklists(Daget et al. 1984, 1986a, 1986b and 1991) andregional overviews of fish diversity are available(Teugels et al. 1994; Stiassny 1996; Lévêque 1997).Yet despite this extensive knowledge, the a great dealof undescribed species still remains. For example,the rate of species discovery for three families—Citharinidae, Mormyridae, and Cichlidae—over thelast century shows the steady growth in the cumu-lative number of species described, which rangefrom 50 to 200 species per decade (Lundberg et al.2000). Even in well-sampled locations, such as LakeVictoria and in the Cross River in Cameroon andNigeria, recent studies have found previouslyunknown species, particularly cichlids. Endemiccichlid fauna in the East African Great Lakes are stilllargely undescribed. In Lake Malawi, 300 endemiccichlids have been described so far, yet this is con-sidered less than 40% of the estimated total num-ber of cichlids in the lake. The situation is similarin Lakes Tanganyika and Victoria (Snoeks 2000). Ingeneral, the most well documented areas are locatedin West Africa, Southern Africa, Madagascar, andthe East African lakes. Areas that are still poorlysampled include: Lower Guinea (coastal rivers ofCameroon to the mouth of Congo River), part ofthe Congo River basin, the Angolan coastaldrainages and the coastal drainages of Mozambiquebetween the Ruvuma and the Zambezi rivers(Lévêque 1997; Skelton 1994).


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The status of African fish fauna has not beencomprehensively assessed, however, there are a fewwell-documented cases. The most widely knownand frequently cited is the disappearance of over300 haplochromine cichlids in Lake Victoria andthe decline or disappearance of most of the riverinefauna in the east and northeastern forests ofMadagascar (Stiassny 1996). There is also docu-mented evidence of the threatened fish fauna ofcrater lakes in western Cameroon and the SouthAfrican fish fauna, which has 63% of its speciesendangered, threatened, or “of special concern”(Lévêque 1997; Moyle and Leidy 1992). The IUCNRed List reflects this assessment bias with 120threatened fishes included, most of which arereported from East African lakes, South Africa,Madagascar, and Cameroon (Hilton-Taylor 2000).

In South America, the Neotropical ichthy-ofauna is very large, estimated to contain as many as5,000-8,000 species. There are five dominant groupsof fishes in this region: Characiformes with a totalof 1,300-2,000 estimated species and 450 describedspecies between 1950 and 1997, Siluriformes with1,400-2,000 species, Gymnotiformes with 94 iden-tified species, and an estimated total of over 100,Cyprinodontiformes with close to 375 species, 203described between 1950 and 1997, and Cichlidaewith about 450 species. Neotropical cichlids are notas diverse as their African counterparts, but thenumber of described species is increasing—about30% of them have been described since 1974(Lundberg et al. 2000).

The pattern of diversity based on the numberof species by river basin without taking basin areainto consideration, shows that the Amazon basin isby far the richest river basin in the world, contain-ing an estimated 3,000 species (Revenga et al. 1998).Other river basins with high number of species arethe Orinoco and the Paraná, each with over 300species, followed by the Magdalena and theUruguay basin containing over 140 species of fresh-water fish. Other major river systems for which nospecies data were available include Rio Colorado inArgentina, the São Francisco, and the Tocantins,

both in Brazil. In terms of endemism, the large riversystems in South America, for which data wereavailable, all seem to contain a high percentage ofendemic fish. Lakes Titicaca and Salar de Uyunishared by Bolivia and Peru, for example contain arelatively low number of species, but a high degreeof endemism—70%. Of the Amazon’s 3,000species, 60% are endemic, followed by the Orinocoand Uruguay rivers with 28% and 22% endemismrespectively. For other important river systems inSouth America, such as the Magdalena, Paraná, andParnaiba data on endemics were not available(Revenga et al. 1998). Further north or south withinthe continent, fish diversity by basin drops sharply.Rivers draining into the Caribbean and the Pacific,or rivers in the southern temperate zone, taxonomiccomposition of the fauna changes and is less diverse(Lundberg et al. 2000).

There is no comprehensive inventory or assess-ment for the Neotropical fish fauna (Lundberg etal. 2000). The Catalog of Fishes (Eschmeyer 1998) isthe most thorough list of the Neotropical ichty-ofauna and has substantially improved accessibilityof the existing information. Data on new speciesdescribed between 1950-1997 shows the increase inthe number of new species described each year andindicates many previously under-sampled areas andtaxa. This increasing trend is expected to continuebecause there are still areas to be discovered and re-discovered. For example, a 1997 list of Venezuelanfreshwater fishes contained 1,065 species—morethan twice of what was published in the first com-prehensive list in 1970 (Lundberg et al. 2000.) Anassessment of the conservation status of fishes hasnot been conducted in the region except forMexico, which accounts for 78 species of threatenedfishes according to IUCN (IUCN 2002).

Museum collections of South American fishesare far more advanced than that of African andAsian fishes, especially in terms of its accessibility.The Inter-Institutional Database of FishBiodiversity in the Neotropics (NEODAT) is aninternational cooperative effort to make availablesystematic and geographic data on Neotropical


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freshwater fish specimens deposited in natural his-tory collections in Europe and the Americas. Anon-line database for museum records has compilednearly 400,000 primary and 120,000 localityrecords from 24 institutions worldwide. Localitydata that include latitude and longitude can also bemapped on-line. This initiative demonstrates thecrucial need for geo-referencing the localities,which enables the assessment of species ranges,patterns of richness, and facilitates the identifica-tion of data and information gaps.

Three quarters of the world’s islands are foundin the Pacific Ocean. Included in these are archaiccontinental remnants like New Zealand and NewCaledonia, detached continental islands (NewGuinea), isolated archipelagos (Hawaii, Galapagos),galaxies of remote volcanic islands (Societies,Marquesas), and low-lying biologically depauper-ate atolls (Tuomotus) (Keast 1996). In terms offreshwater fish fauna, these islands are also unique.

Australia and New Guinea have strong biogeo-graphic affinity in freshwater fish fauna becausethey were connected throughout most of their geo-logical history. The fish fauna of New Guinea-Australia is very different to that of othercontinental tropical regions such as Southeast Asia,Africa, and South America (Allen 1991). Dominantforms are clupeids, plotosid and ariid catfishes,atherinids, melanotaeniids, ambassids, gobiids, andeleotrids. In contrast to the primary division formsthat have evolved entirely in fresh water, they areconsidered to be secondary division of fishes ofmarine origin. In fact all of New Guinea-Australia’sfish fauna except the lungfish (Neoceratodus), bonytongues (Osteoglossus), and possibly galaxiids (seebelow), are considered to be derived from marineancestors. The very different complexion of the fishfauna compared to other regions is a reflection ofthe long period of isolation (approximately 500million years) since the Australian land mass brokeaway from Antarctica and began drifting north-wards towards its present position (Allen 1991).

Despite Australia’s size its river network ismuch less extensive. Nevertheless, Australia har-

bors a large variety of freshwater habitats rangingfrom tropical streams to alpine lakes andephemeral desert lakes. Of the 180 freshwater fishspecies known in Australia, about 108 are foundin the southeast. Of these 86 are native toAustralia. In addition to species that are clearly‘freshwater fishes’, the fauna includes many thatmay or must spend a part of their lives in the sea.Some of these belong to the Galaxiidae, an archaicsouthern group, which has 18 Australian, over20 New Zealand (many non-migratory specieshave only been recently described), 1 NewCaledonian, and 4 Patagonian-South Americanspecies. Reasons why New Zealand has a smallfreshwater fish fauna has much to do with thecountry’s long and great geographical isolationfrom other landmasses in the southwestern Pacificregion but also much to do with its turbulent geo-logical history. However all but five of the 38species found in New Zealand freshwaters areknown only from New Zealand. The longfin eel,which reaches a length of about 2.0 m and weighsup to about 25 kg, makes it arguably the largestfreshwater eel in the world (McDowall 2000).

Fishes found in freshwater described so far inNew Guinea number about about 330 species,including close to 100 species which are basicallyestuarine forms and relatively widespread outsideof New Guinea. The remaining species are exclu-sively freshwater indigenous species. It is this lattergroup that gives New Guinea its unique “flavour”(Allen 1991). Most of the families and many of thegenera have strong Australian affinities. As inAustralia, the most diverse taxa in New Guinea arealso Eleotrididae and Gobiidae, with 115 species,followed by Melanotaeniidae with 53 species. About50 species from southern New Guinea also occurin northern Australia and are restricted to thesetwo areas (Lundberg et al. 2000).

The Murray-Darling basin, the largest river sys-tem in Australia, contains 33 fish species including7 endemics. The Fly basin in southern New Guineahas 105 species and Sepik basin, to the north, has57 species of fish (Revenga et al. 1998). These are


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locally important but less diverse relative to othertropical rivers in Asia. Other areas of locally impor-tant fish diversity include the Aikwa (Iwaka) Riverin Irian Jaya, Lake Kutubu and the in the KikoriRiver in Papua New Guinea, and Tasmania andSouthwest Western Australia (Groombridge andJenkins 1998).

Two closely related families are unique to theAustralo-Papuan zoogeographic region: theMelanotaeniidae (rainbowfishes—famous amongtropical fish aquarists and naturalists) andPseudomygilidae (blue-eyes) (Keast 1996). LargeNew Guinean rivers like the Fly have a high diver-sity of ecomorphological types of fishes (Roberts1978). Many of the rainbowfishes appear to berestricted to an isolated lake or small part of ariver system, making them very vulnerable toenvironmental disturbances like logging or damconstruction. Lake Sentani in Irian Jaya and LakeKutubu in Papua New Guinea are two areas thathave unique fish faunas that are extremely vulner-able (Allen 1991).

Fiji has a substantial fresh and brackish-waterfauna of at least 80 species represented by 28 fam-ilies (Ryan 1980). This diversity compares wellwith other neighbouring islands such as Vanuatu(60 species), French Polynesia (32 species—7endemics (Marquet 1993)) or Palau (40 species)or even the Cape York Peninsula in Australia (30species). It may be explained by the old age ofsome of the islands (Vitilevy is at least 40 millionyears old and has therefore given ample time forboth colonisation and speciation. Many of thespecies have marine larval stages and this influ-ences greatly the level of endemism). It is likelythat there are 10 or more endemic gobies account-ing for around 30% of the total gobiid fauna andaround 12.5% of the total freshwater/brackishwa-ter fauna of these areas (Ryan 1991).

The number of freshwater endemic fishspecies is also limited in New Caledonia with only5 endemic genera (out of 26—mainly representedby Eleotrididae and Gobiidae), 15 endemic species(out of 59), i.e. about 30% of endemic species. The

explanation here again is the marine origin of allbut two families (Séret 1997).

As opposed to North America and Europe,where there have been few fish species discoveriesin recent years, in Oceania, over 30% of the totalnumber of species have been identified since 1970.Many more surveys are still needed in somepoorly-sampled areas of Australia and NewGuinea, particularly Irian Jaya. Taxonomic re-eval-uations of more common species are also needed(Lundberg et al. 2000). There are 44 threatenedray-finned fishes according to IUCN, the majorityof which are reported from Australia, with PapuaNew Guinea and New Zealand making up the rest.Many of them are Perciforms and Salmoniforms(Hilton-Taylor 2000).

Europe contains 358 species of freshwater fish,62 of which are threatened. The IUCN Red Listncludes numerous sturgeons, barbs, and othercyprinid fishes (IUCN 2002). The major groupsaccounting for 80% of the taxa west of the UralMountains are: Cyprinidae (129 species), Salmon-idae (54), Coregonidae (whitefish, 43 species),Gobiidae (31 species), Cobitidae (loaches, 21species), Petromyzontidae (lampreys), Clupeidae(herrings), and Percidae (perches) with 11 specieseach. Like in North America, it is now uncommonto discover new species of fish in European waters.Recent discoveries have been of very small species(3-10 cm in size), mostly from the Iberian, Italian,and Balkan peninsula (Lundberg et al. 2000). TheEuropean fish fauna is less diverse than in temper-ate North America. The river system that containsthe largest number of species is the Danube, with103 species, followed by the Volga with 88 species.Other major river basins that are smaller in size,contain fish species numbers ranging from 30 to70. Very few endemics are reported by river basinin Europe (Revenga et al. 1998). These low num-bers of species and endemics may also reflect thehigh degree of modification of European rivers andits impact on their fish fauna.

Over 1,050 freshwater fish species are knownto occur in North America, representing 32 prima-


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rily freshwater families and 24 marine families thatcontain a few freshwater members. The dominantgroups that constitute about 80% of the totalspecies are Cyprinidae (305 species), Percidae (172species), Poeciliidae (livebearing poeciliids, 75species), Castomidae (suckers, 68 species),Ictaluridae (catfishes, 48), Goodeidae (livebearingfishes, 40), Fundulidae (topminnows and killifishes37), Centrarchidae (sunfishes, 32), Atherinidae (sil-versides 35), Cottidae (sculpins, 27), and Cichlidae(cichlids, 21). The continent’s fish fauna contains 9families and 128 genera endemic to the region(Lundberg et al. 2000). The Mississippi basin is anoutstanding centre of ichtyofauna diversity, harbor-ing 375 species of which over 30% are thought tobe endemic. The Rio Grande, Colorado, Alabama,and Susquehanna River systems have very diversefish fauna for a temperate region, each containingover 120 species. Fish endemicity is also very highin the Rio Grande (57%), Colorado (35%), andUsmacinta basins (59%) (Revenga et al. 1998).

Freshwater fishes of North America have beenthoroughly explored in the last two centuries.Except for Mexico and Central America, there arefew unknown species. Species distribution is welldocumented at regional, provincial, and state level.Assessments of the conservation status of freshwa-ter fishes are extensive: of the 645 ray-finned fisheslisted as threatened in the IUCN Red List, 119 arefound in the U.S. and 78 in Mexico (IUCN 2002).

3.8 AMPHIBIANS

Amphibians are strictly freshwater animals, unableto tolerate salt water. They are found in all types offreshwater habitats from ponds, streams, and wet-lands, to leaf litter, on the tree canopy, underground,and in vernal pools. Although some amphibiansthrive in cold or dry conditions, the group reachesits highest diversity and numbers in warm, humidclimates (Hebert 2002). Amphibians are classifiedinto 3 orders: Anura (frogs and toads), Caudata(newts and salamanders), and Gymnophiona (cae-cilians). Estimates of the actual number of extant

amphibian species vary among taxonomists andauthors. Duellman (1993) lists 4,522 species ofamphibians, based on data and information avail-able in 1992. The on-line resource AmphibiaWeblists almost 5,500 species. Diversity and distributionof the group is better known in the developed world.A total of 74 amphibians are known in Europe, withthe highest numbers occurring in France, Italy,Spain, and former Yugoslavia (20-30 species each)(Corbett 1989). Approximately 230 species ofamphibians occur in the continental United States,including 140 salamander species and 90 anurans.The ranges for most endemic species in the westernUnited States (26 species) are widely dispersed whileendemics in the eastern and southeastern U.S. (25species) tend to be clustered in centers of endemism,such as in the Edwards Plateau in Texas, the InteriorOzark Highlands in Arkansas and Oklahoma, theAtlantic Coastal Plain from Texas to Virginia, andthe uplands or mountaintops in the AppalachianMountains (Bury et al. 1995). In Japan a total of 59amphibians have been described to date, many ofwhich are salamanders (Japanese Council ofMinisters for Global Environmental Conservation1995). The American Museum of Natural Historymaintains an on-line catalog of the world’s amphib-ian species with a bibliography containing over 7,100references (Frost 2000). Although still incomplete,this is the most comprehensive and up-to-dateglobal list that currently exists.

Duellman’s 1993 classification provides anoverview of the distribution of species between the3 orders. However, because of constant updatingand revision of taxonomic names and new speciesbeing identified, these figures may not accuratelyreflect the current state of knowledge of amphibiansystematics. Of Duellman’s estimated 4,522 speciesof amphibians, the majority (3,967) belongs to theorder Anura, 392 species are newts and salamandersand 163 species belong to the order Gymnophiona(Duellman 1993).

The IUCN Red List of Threatened Animals(IUCN 2002) lists 142 “freshwater-dependent”amphibian species as either critically endangered,


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endangered, or vulnerable to extinction, of which113 are frogs or toads and 27 are newts or salaman-ders. Two additional caecilian species are reportedas threatened in the Philippines. The threatenedAnura species include 34 in Australia, 21 in thePhilippines, 15 in South America, 15 in African, 8in the Caribbean, 8 in the U.S., and 4 in Japan.There are as many as 67 species still listed as “datadeficient” that are potentially threatened, themajority of which are found in South America.Some global data for declines in Amphibia areshown in Map 4 (see Appendix A, page 120).

Of the 27 species of newts and salamanderslisted as threatened, 9 are found in the U.S., 8 in theCaribbean, 6 in Japan, and 4 in Europe. There are 7additional species listed as “data deficient” that arepotentially threatened.

In addition to the conservation assessmentscarried out by IUCN for the Red List, research todate shows that globally over 200 amphibianspecies have experienced recent population declineswhile 32 are reported extinct (Blaustein and Wake1990, Alford and Richards 1999, Houlahan et al.2000). Experts believe that the population declinesare due to multiple factors including habitatdestruction, climate change, ultraviolet radiation(because of the reduction of the ozone layer), con-taminants, introduced species, infectious bacteria,fungi and viruses. Most alarming is that many ofthese declines have occurred in pristine protectedareas (Amphibia Web 2002). Due to the lack oflong-term monitoring of amphibian populations,the evidence of these declines is mostly anecdotal.The Declining Amphibian Populations Task Forceof the IUCN/Species Survival Commission hasassessed these documented incidents worldwide.Although the cases of amphibian declines are notevaluated with standard criteria, the results showmarked declines in the populations of easternAustralia, southeastern Brazil, Central America, andat higher altitudes in the U.S. and Canada (Revengaet al. 2000).

In response to this global phenomenon, theGerman Federal Ministry of Education and

Research and the Zoology Department of MainzUniversity, in collaboration with local organizationshave founded the Global Amphibian DiversityAnalysis Group (GADAG) under their BIOLOGprogram. GADAG has initiated long-term moni-toring projects and has other activities planned ata number of localities in East and West Africa,Southeast Asia, South America, and Madagascar(GADAG 2002). IUCN and ConservationInternational have also initiated a global amphib-ian assessment, the results of which will be pub-lished in early 2004.

3.9 REPTILES

3.9.1 Freshwater Turtles

There are around 200 species of freshwater turtlesthroughout the warm temperate and tropicalregions of the world (IUCN/SSC Tortoise andFreshwater Turtle Specialist Group 1991). They playan important role as scavengers (eating carrion,weeds, insects and snails) and therefore contributingto the maintenance of the ecosystem. Turtles areharvested and used by humans throughout theirrange. Most turtle species are edible and are espe-cially valuable as food (both flesh and eggs) in manydeveloping and some developed countries. Turtlesare also used for products such as souvenirs, tradi-tional medicines, aphrodisiacs and the internationalpet trade. These pressures in combination withhabitat loss are causing declines in turtle popula-tions worldwide (van Dijk et al. 2000).

There are two taxonomic suborders of livingturtles. One comprises the Pleurodira or side-necked turtles, which are only found in theSouthern Hemisphere, and are characterized byfolding their neck to the side rather than draw itinto the shell between the shoulder blades. Theside-necked turtles are primitive, semi-aquatic tur-tles that include two distinct taxonomic families.The Chelidae with 36 species distributed through-out Australia, New Guinea, and South America,and the Pelomedusidae with 23 species, found in


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Africa and South America. (Ernst and Barbour1989; Meylan and Ganko 1997). In terms of theirconservation status, IUCN lists 2 Pelomedusidaespecies, the Madagascar big-headed turtle inMadagascar and the Magdalena River turtle inColombia, as endangered and 6 species as vulnera-ble to extinction (IUCN 2002). Within theChelidae family, there are 3 species considered crit-ically endangered, 1 is found in Indonesia, 1 inColombia and 1 in Australia. Four more species areclassified as endangered, including 1 species inBrazil, 2 in Australia and 1 in Papua New Guinea:Chelodina pritchardi the only endemic turtle foundin Papua New Guinea, and illegally hunted for thepet trade. There are 6 additional Chelidae specieslisted as vulnerable to extinction (IUCN 2002).

The other taxonomic suborder, the Cryptodiraor hidden-necked turtles, includes all the remain-ing living turtles of the world, including freshwa-ter and marine turtles, and land tortoises. Allmembers of this suborder can retract the neck andmost of them also the head into the shell betweenthe shoulder blades. Of the 12 living families ofturtles, 10 families are cryptodirans and 2 side-necked turtles.5 The Cryptodira include snappingturtles, sea turtles, soft-shelled turtles, mud andmusk turtles, pond, box and water turtles, land tor-toises, and the two single species of two relictualfamilies, the Fly River or Pig-nosed turtle found inNew Guinea and Australia and the Tortuga Blancaor Central American river turtle found in Mexico,Belize, Guatemala and Honduras (Ernst andBarbour 1989; Meylan and Ganko 1997; Uetz andEtzold 1996). These last two species are consideredvulnerable and endangered respectively, primarilyfrom habitat loss and exploitation (IUCN 2002).

The snapping turtles (Chelydridae) containonly 3 species in three monotypic genera. Theyinclude the alligator snapping turtle (Macrochelystemminckii), the heaviest freshwater turtle in theworld (up to 80 kg), which is endemic to the U.S.and found exclusively in rivers draining to the Gulfof Mexico (Ernst and Barbour 1989). This species

is considered vulnerable, mainly due to habitat lossand degradation, and exploitation (meat) for inter-national and domestic markets (IUCN 2002). Thecommon American snapping turtle (Chelydra ser-pentina) is found in North America and as farsouth as Peru, in both fresh and brackish water(Ernst and Barbour 1989). The third species ofsnapping turtle, the big-headed turtle (Platysternonmegacephalum), is found in China and SoutheastAsia, where it inhabits cool mountainous rockystreams. This turtle has “a head so large that it can-not be withdrawn into the shell” (Ernst andBarbour 1989). This species is considered endan-gered mostly because of trade (IUCN 2002). Ernstand Barbour (1989) consider this species to be theonly representative of a separate taxonomic family,the Platysternidae.

The Trionychidae or soft-shelled turtles aresemi-aquatic flat turtles with leathery shells, pad-dlelike-limbs, and usually a long snout. They aredistributed in Africa, Asia, Indonesia, Australia andNorth America. This group contains 14 genera and22 species (Ernst and Barbour 1989). There are 14species of soft-shell turtles listed as critically endan-gered, endangered or vulnerable to extinction byIUCN (2002). Some of the critically endangeredspecies, such as the Cuatro Ciénagas softshell, havevery restricted ranges, Therefore minor changes totheir habitat can have devastating effects on thepopulation. The food and pet trade, particularly inSoutheast Asia, threaten many of these species. Evenspecies that are commercially farmed in large num-bers (up to several millions per year) for the foodtrade, such as Pelodiscus sinensis, are threatened inthe wild due to overexploitation (IUCN 2002).

The mud and musk turtles are small andmedium sized, aquatic and semi-aquatic turtlesbelonging to the family Kinosternidae. There are 3genera and 22 species found exclusively on theAmerican continent (Ernst and Barbour 1989).IUCN lists 4 species as vulnerable to extinction, 2of which are found in the U.S and Mexico, 1 inCentral America and 1 in Colombia (IUCN 2002).


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5 Some authors classify the living turtles into 13 families instead of 12 (Meylan and Ganko 1997).


Pond, box and water turtles belong to the fam-ily Emydidae. Many authors, including Ernst andBarbour (1989), classify the Emydidae turtles intotwo subfamilies: Batagurinae or old world pondturtles and Emydinae or new world pond turtles.However, several authors consider the batagurs asa complete separate family (Bataguridae) (Uetz andEtzold 1996, IUCN 2002). The pond turtles andtheir allies are the most diverse group, representedin all parts of the world except for Australia andAntarctica. They are mostly aquatic or semiaquaticfreshwater turtles, with the exception of two species(Callagur borneoensis and Malaclemys terrapin),which nest on beaches or inhabit brackish marshesalong the coast. They also contain several terrestrialgenera. There are 91 living species of pond turtles,belonging to 33 genera (Ernst and Barbour 1989;Uetz and Etzold 1996). There are 13 threatenedspecies of new world pond turtles, the majority ofwhich are restricted to areas in the U.S. andMexico, with a few species being native to Brazil,Jamaica, and Haiti (IUCN 2002). With respect toold world pond turtles, IUCN lists 40 species asthreatened, of which 12 are critically endangered,18 endangered and the rest classified as vulnerableto extinction (IUCN 2002). The major threat to allthese species is trade either for food or as pets.Several species are still traded even though they arelisted in CITES Appendix I (IUCN 2002).

The number of critically endangered freshwa-ter turtles has more than doubled in just the last 4years, according to IUCN, Trade Records Analysisof Flora and Fauna in Commerce (TRAFFIC),Wildlife Conservation Society (WCS), WWF, andother conservation groups (van Dijk et al. 2000).Three-quarters of Asia’s freshwater turtles are listedas threatened, and over half considered endangered.Imports of turtle shells into Taiwan alone, for exam-ple, comprise on average over 30 metric tons peryear, and the total trade may add up to several timesthis amount (TRAFFIC 2002). According to theIUCN/SSC Tortoise and Freshwater Turtle SpecialistGroup and the Asian Turtle Trade Working Group,of the 90 species of Asian freshwater turtles and tor-

toises, 74% are considered threatened. Over half ofAsian freshwater turtle and tortoise species areendangered, including 18 critically endangeredspecies, and one that is already extinct: the Yunnanbox turtle Cuora yunnanensis (van Dijk et al. 2000).The increase in trade of turtle species and their con-tinuing population declines prompted China,Germany, India and the United States to submitproposals for inclusion of several freshwater turtlespecies under Appendix II of CITES in order tocontrol their trade. At the last CITES Conference ofthe Parties, held in Santiago de Chile, November2002, 11 of these proposals were accepted by con-census. The accepted proposals include listing inCITES Appendix II the following freshwater turtles:the big-headed turtle, the Annam pond turtle, theyellow-headed temple turtle, all Kachuga speciesexcept for K. tecta, the yellow pond turtle, theMalaysian giant turtle, the Sulawesi forest turtle, thekeeled box turtle, the black marsh turtle, the giantsoftshell turtle, and all the softshell turtles in thegenus Chitra (CITES 2002). In addition and to aidin curbing the illegal trade in turtles and tortoises,Environment Canada and collaborators have pro-duced a manual on the identification of turtles andtortoises as part of their CITES Identification Guideseries (CITES 2002).

Southeast Asia harbors a great variety of fresh-water and semi-aquatic turtle species comprisingapproximately 39 species. The two most diversegroups of turtles in this region are the pond turtles,with 27 species and the softshells with 15 speciesfound in tropical Asia, and nine of these specificallyin Southeast Asia (Jenkins 1995). All freshwater tur-tles are traded throughout SE Asia for use as food,in traditional medicine, as souvenirs, aphrodisiacsand in the international pet trade. Softshells areused throughout the region as food, and in Chinesemedicines. Pond turtles are less marketable as foodthan the softshell turtles, instead they are used morein medicines (Jenkins 1995).

The conservation status of softshells in theregion varies from one country to another. Thelimited amount of information for Cambodia and


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Laos PDR, for instance, indicates that softshells areexported regularly, mostly to Vietnam, and in mostcases are further exported. Experts believe thatmost of the time the final destination for the tradeis China. In Indonesia and Thailand, export andconsumption of softshells is widespread and hasincreased in recent years. In Thailand, much of thetrade is illegal, given that current laws in the coun-try protect all softshell species. Since the early1990s, trade in softshells in Thailand seems to havedeclined, but the cause of this decline is not clear.Thailand is also a major breeding center for soft-shells, especially for the Chinese market, Japan,Korea, Taiwan and Hong Kong. This trade was esti-mated in 1995 to be around US$3-6 million peryear (Jenkins 1995).

In the Peninsula of Malaysia there are 15species of freshwater and semi-aquatic turtles. Themain threats to these species are: loss and degrada-tion of nesting habitat in coastal and riverine areas,alteration of habitat (drainage of wetlands, etc.),harvest and consumption of eggs, and exploitationfor food. A few species are commercialized for thepet trade. There are 13 turtle species classified ascritically endangered, endangered or vulnerable toextinction by IUCN (IUCN 2002). In Malaysiaconsumption seems to have decreased, but thismay be related to a shortage of supply rather thanto a change in food preference. In Myanmar, tradein turtles is forbidden, but they are extensivelyharvested for food in certain parts of the countryand some illegal trade is suspected (Jenkins 1995;Sharma 1999).

Finally a third group of turtles, highly threat-ened in the region and among the most threatenedin the world are the large-river terrapins. Not muchinformation is available on the exploitation or sta-tus of this group across SE Asia, however, it seemsthat in places, like Indonesia trade is increasing(Jenkins 1995).

Another area for which information on the sta-tus of turtles is available is India. There are 22 speciesof freshwater and semi-aquatic turtles in India, 15of which are critically endangered, endangered or

vulnerable according to IUCN (IUCN 2002).The major regions of the country where a highdiversity of turtle species can be found are the flood-plains of the Brahmaputra, Ganges, and theMahanadi watersheds. The species found in theGanges and Mahanadi as well as the ones in north-eastern India, for example, have been heavily affectedby exploitation and habitat destruction. Two brack-ish-water species have been practically wiped out(Choudhury and Bhupathy 1993). Exploitation ofturtles in India is mostly geared towards food, tra-ditional medicine, religious rites, and the pet trade.

Information on location and distribution ofindividual species of freshwater and land turtles ofthe world is available through the World TurtleDatabase, compiled by the Geosciences Departmentof Oregon State University (OSU) in Corvallis,Oregon (World Turtle Database http://emys.geo.orst.edu/). The database contains maps of all theknown localities of every land and freshwater tur-tle species “that has been collected by a museum,private individual, or referenced in a publication.”The information provided on the website is fromIverson (1992), Revised Checklist with DistributionMaps of the Turtles of the World.

3.9.2 Crocodilians

Crocodiles, alligators, caimans and gharials arewidespread throughout tropical and subtropicalaquatic habitats. There are 23 species of crocodil-ians distributed in tropical America, Africa, SouthAsia, and Oceania. They are top predators in fresh-water habitats and therefore are key to maintain-ing ecosystem functions, including selectivepredation of certain fishes, nutrient recycling, andmaintenance of wet refugia during drought peri-ods (Ross 1998). Crocodilians usually live in wet-lands, marshes, swamps, rivers and lagoons and themajority of the species require large areas(hundreds of square kilometers) of undisturbedwetlands to maintain large populations.

In the Americas, there are 10 species of croco-dilians: the American alligator (Alligator mississippi-


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ensis) found in Southeast US, along the Atlanticcoastal plain through southern Florida and westalong the coast to eastern Texas; the commoncaiman (Caiman cocodrilus), which has a wide dis-tribution along most of tropical Central and SouthAmerica; the black caiman (Malanosuchus niger)found in the Amazon basin and coastal rivers ofBrazil, Guyana and French Guiana; the broad-snouted caiman (Caiman latirostris), which can befound in coastal streams and swamps along thesouthern part of Brazil, and in some inland riverbasins like the São Francisco, Doce, Paraiba, Paranáand Paraguay in Brazil and Argentina; Cuvier’sdwarf caiman (Paleosuchus palpebrosus), which isdistributed throughout the Orinoco, Amazon, SãoFrancisco river basins and the upper reaches of theParaná and Praguay rivers; Schnieder’s dwarf caiman(Paleosuchus trigonatus) found in the forestedregions of the Amazon and the Orinoco, and in theGuyana region; the Cuban crocodile (Crocodylusrhombifer) restricted to a 500 km2 area in southwest-ern part of the island, in the Zapata Swamp. It isbeing bred in captivity and has been re-introducedinto the Isle of Pines (IUCN/SSC CrocodileSpecialist Group 2002 ); Morelet’s crocodile (Croco-dylus moreletii) found throughout the YucatanPeninsula, to Chiapas, Belize and the Peten regionin Guatemala; the American crocodile (Crocodylusacutus) found from southern Florida, throughoutthe Caribbean and the coasts of Central America toColombia and Venezuela; and the Orinoco croco-dile (Crocodylus intermedius) restricted to the fresh-water reaches of the Orinoco River.

Africa has 3 crocodilian species, including theAfrican slender-snouted crocodile (Crocodylus cat-aphractus), the Nile crocodile (Crocodylus niloticus),and the African dwarf crocodile (Osteolaemus tetrap-sis). The Nile crocodile is the most widespread of the3 species found throughout tropical and southernAfrica, including Madagascar. It also used to befound in the Nile delta and throughout parts of theMediterranean coast and in some inland lakes inMauritania, Chad and the Sahara Desert. TheAfrican slender-snouted crocodile and the dwarf

crocodile on the other hand are limited to tropicalforest regions in Africa. The slender-snouted croco-dile can be found throughout central Africa, includ-ing Zambia, and eastern Tanzania, while the dwarfcrocodile can only be found from Senegal to Angola,and Northeastern Zaire and Uganda.

In Asia and Oceania, there are 9 species ofcrocodilians, including the true gharial (Gavialisgangeticus), and the single Asian alligator species,the Chinese alligator (Alligator sinensis). The ghar-ial is found exclusively in the northern part of theIndian subcontinent, although historically it couldbe found in the rivers of Pakistan, Nepal, India,Bangladesh, Bhutan and Myanmar. The Chinesealligator is restricted to a small area in the lowerYangtze River. The remaining 7 species are all croc-odiles. These include, the Johnston’s crocodile(Crocodylus johnsoni) found in the northern trop-ical areas of Australia; the Philippine crocodile(Crocodylus mindorensis), which used to be foundthroughout the Philippine archipelago but hasbeen eliminated from 80% of its former range.Currently, the only remnant population is inMindanao with some individuals scattered onother islands (IUCN/SSC Crocodile SpecialistGroup 2002); the New Guinea crocodile(Crocodylus novaeguineae) found exclusively inPapua New Guinea and Irian Jaya; the saltwatercrocodile or Indopacific crocodile (Crocodylus poro-sus) whose distribution extends throughout thetropical regions of Asia and the Pacific, which hasthe most commercially valuable hide of any croc-odilian; and the Siamese crocodile (Crocodylus sia-mensis) which is only found in small populationsin Laos, Vietnam, and Indonesia. It has been erad-icated from much of its former range and has prac-tically disappeared from Thailand (IUCN/SSCCrocodile Specialist Group 2002); the marsh orbroad-snouted crocodile (Crocodylus palustris)which is distributed throughout the Indian sub-continent; and the false gharial (Tomistomaschlegelii), confined to a few areas, including theMalay Peninsula, Sumatra, Borneo, Java and pos-sibly Sulawesi (Ross 1989).


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Of the 23 species, 15 are traded commerciallyfor their skin and all 23 species are listed in CITESAppendices. The historical peak of the crocodileskin trade was in the 1950s and 1960s when500,000 skins were traded per year. This quantitydeclined during the two following decades due tooverexploitation of the wild populations. In the1980s, and after CITES entered into force, manage-ment of crocodiles and alligators by farming andranching developed. Today, trade has not reachedthe high levels of the 1950s. In 1990 for example,around 220,000 skins were traded legally. The legalinternational trade in crocodile skins is worthUS$500 million per year, with Europe and Japanbeing the two most important markets.

The two major threats to crocodilians world-wide are habitat loss and degradation, and overex-ploitation. Habitat degradation is caused bypollution, drainage of wetlands, deforestation, andconversion of wetlands to cropland. The deliberatedestruction of nests and killing of adults byhumans as well as the illegal hunting for their skinalso pose a threat to some species. These are fre-quently reported from Madagascar, Philippines,China, and Bangladesh. Of the 23 species of croco-dilians, 4 are critically endangered, 3 are endan-gered, and 3 vulnerable. The most threatenedcrocodilian is the Chinese alligator, whose distri-bution has been restricted to small areas in thelower reaches of the Yangtze River and its tributar-ies. Pressure from land use change, agriculture, pol-lution, deforestation, water extraction, etc., furtherreduces the little habitat available. It is estimatedthat less than 150 individuals remain in the wild(IUCN/SSC Crocodile Specialist Group 2002 andRoss per. comm. 2002). The other 3 species that arecritically endangered are the Philippine andSiamese crocodiles in Asia, and the Orinoco croco-dile in South America. The 3 endangered speciesinclude the gharial, the false gharial, and the Cubancrocodile. Finally the vulnerable species include theAmerican crocodile, the marsh or broad-snoutedcrocodile with less than 2,500 adults remaining inthe wild, and the African dwarf crocodile (IUCN

2002). The African slender-snouted crocodile isconsidered data deficient. The other species areestimated to be at lower risk of extinction althoughdepleted locally in some places (Ross 1998).

3.9.3 Freshwater Snakes

There are several species of freshwater snakes in theworld. The members of the family Acrochordidaealso known as wart or file snakes, for example, areadapted to aquatic life by having dorsal eyes, valvu-lar nostrils, and a flap for closing the lingual open-ing of the mouth (Uetz and Etzold 1996). Thisfamily has 3 species, two adapted to freshwater habi-tats, the file snake (Acrochordus arafurae) and theJavan wart snake (A. javanicus), and one adapted tothe marine environment. Both freshwater speciesare found in the Indo-Pacific region. File snakescontinue to be important food for Aboriginal com-munities in northern Australia (Shine 1991 as citedin the Animal Diversity Web 2002). There is notmuch information on their conservation status.

The Javan wart snake lives in brackish waterof rivers and estuaries, along coastal India, SriLanka, and across the Indo-Pacific islands as far asthe Solomons. This species can also make shortincursions into the sea. A major threat to thespecies is hunting for its skin, which is used in themanufacturing of leather goods. The Javan wartsnake is becoming increasingly rare (AnimalDiversity Web 2002).

In addition to these two strictly freshwaterspecies there are snakes that are semi-aquatic. Theseinclude many colubrids, such as Mud snakes, Gartersnakes, and species belonging to the genus Helicopsand Hydrodynastes. Helicops and Hydronastes speciesare found in wetland habitats in South America,from French Guyana to the Chaco region inArgentina. The Western mud snake (Faranciaabacura reinwardtii) is found in and around stag-nant, muddy waters along the coast of the Gulf ofMexico in the U.S., while the Rainbow snake(Farancia erythrogramma) is found in rivers in thesoutheastern U.S. (Animal Diversity Web 2002).


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The large-headed water snake (Natrix megalo-cephala) found in Azerbaijan, Georgia, Russia andTurkey is listed as vulnerable to extinction (IUCN2002). The Giant garter snake (Thamnophis gigas)is found in freshwater habitats in the U.S and con-sidered vulnerable. The Brown water snake (Nerodiataxispilota) of the U.S., is found in coastal riversfrom Virginia to Florida and Alabama. This speciesis quite common and currently not threatened. Thecottonmouth (Agkistrodon piscivorus) is found inbrackish waters, swamps, streams, marshes anddrainage ditches in the southeastern United States.The Green anaconda (Eunectes murinus), one of thelargest snakes in the world and the Yellow anaconda(Eunectes notaeus) belonging to the Boidae familyare also aquatic. The Green anaconda is foundmainly in slow running or still waters of theAmazon and Orinoco River basins, but also in riversof the Guiana Shield (Animal Diversity Web 2002).The Yellow anaconda is distributed from northernArgentina, to Bolivia, Brazil and Paraguay. It inhab-its swampy savanna habitats along the Paraguay andParana Rivers (Mattison 1986). These species arelisted in CITES Appendix II, and although theirtrade is prohibited in most South American coun-tries some are periodically exported for zoos,research and the pet trade. There is also some illegaltrade in anaconda skins, but this is not threateningthe species’ survival. Other pressures on anacondasare habitat destruction and killing by local peoplebecause they are perceived as dangerous to the localpopulation (Animal Diversity Web 2002). Thesespecies are not listed as threatened by IUCN.

3.10 BIRDS

Birds can be useful indicator species to assess habi-tat condition. Because of the historical and ongo-ing interest of hunters, scientists, birdwatchers, andothers they have been studied and monitoredmore consistently and for longer periods of timethan many other taxa. Waterbirds (bird speciesthat are ecologically dependent on wetlands) andparticularly migratory waterbirds are probably

“the most comprehensively studied group of ani-mals on earth” (Rose and Scott 1997). For someparts of the world, notably North America andNorthwestern Europe, time-series data on trendsare available for a period of over 30 years.

Given the vast amount of information onbirds in general, and waterbirds in particular, thissection provides only an overview of the statusand trends of waterbird populations primarily atthe global level. In addition, for some waterbirdtaxa information is available at the flyway scale.The information is presented by taxonomic familyfollowed by a summary section of trends in water-fowl populations by geographic region. All fami-lies with a large number of wetland-dependentspecies are included, even though some specieswithin particular families may not be consideredwaterbirds. Many waterbirds are dependent oninland waters at some stage of the year, but itshould be noted that some species in the familiesincluded in this section are predominantly coastal,although parts of such populations may utiliseinland waters.

Importantly, global information on the statusand trends of waterbirds is available for biogeo-graphic populations, rather than just at the specieslevel. A population is defined as a “distinct assem-blage of individuals that does not experience sig-nificant emigration or immigration” (Rose andScott 1997). Information on biogeographic pop-ulations therefore provides a better understandingof the overall condition of a species at the globallevel. For migratory waterbirds this is particularlyimportant since many species are widely distrib-uted but with different populations following dis-tinct and different migratory pathways (flyways),and the status and trends of these populationswithin a species can differ greatly.

Global information on waterbird populationstatus and trends is compiled and regularlyupdated by Wetlands International through itsInternational Waterbird Census (IWC), and pub-lished as Waterbird Population Estimates. Popu-lation status and trend information presented here


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are from the third edition of Waterbird PopulationEstimates published in September 2002 (WetlandsInternational 2002).

Detailed information is also available forwaterbird species in North America, compiled bythe U.S. Geological Service, and for the WesternPalaearctic and South-West Asia by WetlandsInternational (e.g. Delany et al. 1999). For African-Eurasian waterbird populations, comprehensiveanalyses have been compiled for Anatidae (ducks,geese and swans) (e.g., Scott and Rose 1996) andwaders (Charadrii) (e.g., Stroud et al. 2002).Europe-wide national population trends for allbird species, including waterbirds, have been com-piled by BirdLife International (BirdLife Inter-national/European Bird Census Council 2000). Forother regions, although distributional data areavailable, comprehensive information on statusand trends of waterbirds is generally lacking.

3.10.1 Gaviidae (loons, divers)

All populations of the 5 Gavia species are foundin temperate regions (i.e. North America, Europeand Asia). None of the 5 species are consideredthreatened under the IUCN criteria. Trend infor-mation for the 5 species is available for only 5 ofthe 13 identified populations.The North Americanpopulation of G. pacifica and part of the North

American population of Gavia immer are stable,while the arctic population of G. artica and theNorthwestern European and North Americanpopulations of G. stellata are decreasing (WetlandsInternational 2002).

3.10.2 Podicipedidae (grebes)

Grebes include 22 species distributed throughoutall continents, although they are more predomi-nant in the temperate to subtropical climatic zones.The status of grebes is summarized in Table 9.

Two species of grebes, the Colombian grebeand the Giant or Atitlan grebe, went extinct ca.1970. The other possibly extinct species isDelacour’s little grebe from Madagascar. Althoughthis species is listed as critically endangered byIUCN, scientists currently believe that it is morelikely that this species is already extinct (O’Donneland Jon Fjeldsa 1997). The two critically endan-gered species are Delacour’s little grebe and theJunin grebe, the latter of which is endemic andrestricted to one single lake in Peru and whosepopulation has undergone significant decline.Only a very small number of adults remains.

The major threats to grebes are habitat loss,particularly because of conversion to agriculturalland and water abstraction for irrigation, domes-tic and industrial use. Additional threats include


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Table 9. Grebe Species and Subspecies according to IUCN Threat Categories andtheir Geographical Distribution

C. and S. SE Asia Australasia/Africa Eurasia N. America America and China Oceania Total

Total taxa* 5 6 6 21 9 8 55

Extinct 1 (?) 2 3

Critically 1 (?) 1 2Endangered

Endangered 1 1

Vulnerable 1 1 4 3 5 14

Total Threatened 5 1 0 10 7 6 29

* Includes species and subspecies of grebes.

Source: O’Donnel and Jon Fjeldsa 1997


pollution from pesticides, eutrophication, siltation,recreation activities in lakes and wetlands, and theintroduction of fish and other predators and com-petitors. The regions where the pressures ongrebes and their habitats are greatest are Centraland South America, followed by Southeast Asiaand Australasia.

The IUCN/SSC Grebe Specialist Group hascreated a “Global Conservation Strategy toensure the successful recovery of grebe popula-tions and the management of wetlands.” ThisStrategy includes 8 priority areas ranging fromthe immediate development and implementationof recovery plans for critically endangered grebespecies and subspecies including lake restoration,public awareness campaigns, further assessmentof grebe species listed as “data deficient,” moni-toring key grebe populations listed as vulnerable,and the development of methods for usinggrebes as keystone indicator species for monitor-ing wetland health and biodiversity (O’Donneland Fjeldsa 1997). In terms of grebe populationtrends, out of a total of 73 identified populations,12 populations are decreasing, 9 are increasingand 17 are stable. Trend information for theremainder of the populations is not available. It ishowever possible to highlight some regionaltrends. For example, of the decreasing popula-tions, the majority are found in the Andeanregion, particularly populations in Peru andBolivia, and in Africa, particularly in Madagascar(Wetlands International 2002).

3.10.3 Pelecanidae (pelicans)

There are 8 species of pelicans with 20 distinctpopulations, the majority of which are found inAsia, Africa, and the neotropics and fewer popu-lations in North America, Eastern Europe, andAustralasia. Because the available information doesnot separate the inland water populations fromcoastal or marine ones, we have included all pop-ulations in the trends analysis. In terms of the con-servation and threat status of pelican species,

IUCN lists only one species, the spot-billed peli-can (Pelecanus philippensis) as vulnerable (IUCN2002). There are 5 increasing populations all in thewestern hemisphere, 5 declining populations and5 stable populations. Information on the remain-der of the populations is not available (WetlandsInternational 2002).

3.10.4 Phalacrocoracidae (cormorants)

There are 40 species of cormorants and 77 identi-fied populations worldwide. None of the freshwa-ter dependent species within this family is listed asthreatened by IUCN, however there are 10 speciesof marine cormorants that are threatened and onespecies, the Palla’s cormorant (Phalacrocorax per-spicillatus), that is extinct. The Pallas cormorantinhabited the Commander Islands in the BeringSea and it went extinct in the late 1800s (IUCN2002). Information on trends for other populationsindicates that there are a total of 21 stable cor-morant populations, 9 increasing and 8 decreasing(Wetlands International 2002).

3.10.5 Anhingidae (darters)

There are 4 species of darters, and nine distinctpopulations. No darter species is currently listed asthreatened by IUCN. In terms of population trendsthere is information for only 7 populations, 5 ofwhich are decreasing (Wetlands International 2002).

3.10.6 Ardeidae (herons, egretsand bitterns)

There are 65 species of herons and 261 populationsdistributed in all regions of the world. IUCN cur-rently lists 8 species as either endangered or vulner-able. There are also 4 species that have gone extinct,including the New Zealand little bittern, theRéunion night heron, the Mauritius night heron andthe Rodrigues night heron (IUCN 2002). Thirty-sixpopulations are decreasing, 18 are increasing, and 42are stable (Wetlands International 2002).


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3.10.7 Balaenicipitidae (shoebill)

The single species in this group, Balaenices rex, isfound exclusively in tropical Central Africa. Thespecies is listed as near threatened by IUCN (IUCN2002). The current population estimate is around5,000-8,000 individuals with a decreasing popula-tion trend (Wetlands International 2002).

3.10.8 Scopidae (hammerkop)

This is also a single-species family found in Africa.There are 3 distinct populations of Scopus umbrettaor hammerkop, however population trend infor-mation is only available for Madagascar. TheMalagassy population, estimated at 60,000 to 90,000individuals, is believed to be stable or possiblyincreasing (Wetlands International 2002). Thespecies is not listed as threatened by IUCN.

3.10.9 Ciconiidae (storks)

There are 19 species of storks and 39 distinct pop-ulations. In terms of their conservation status,there are 3 species listed as endangered and 2 asvulnerable (IUCN 2002). The endangered speciesinclude the Japanese white stork (Ciconia biy-ciana), Storm’s stork (C. stormi) and the greateradjutant (Leptoptilos dubius). The two vulnerablespecies are the lesser adjutant (L. javanicus) andthe milky stork (Mycteria cinerea). Informationon population trends is available for 29 of the 39populations; of these 17 are decreasing, 4 areincreasing and 8 are stable (Wetlands Inter-national 2002). Many of the decreasing popula-tions are found in Southeast Asia and China,while most of the increasing populations are inSouthern Africa and Europe.

3.10.10 Threskiornithidae(ibises and spoonbills)

There are 39 species of ibises and spoonbills and67 identified populations. One wetland-depend-

ent species, the Réunion flightless ibis (Thres-kiornis solitarius) has already gone extinct. Fourother freshwater dependent species are threatened.These include 2 endangered species in Asia: theJapanese crested ibis (Nipponia nippon) and theBlack-faced spoonbill (Platalea minor); and 2 crit-ically endangered species found in Southeast Asia:the White shouldered ibis (Pseudibis davisoni),and the Giant ibis (Thaumatibis gigantean)(IUCN 2002). Of the populations for which thereis trend information, 19 are decreasing, 16 are sta-ble and 4 increasing.

3.10.11 Phoenicopteridae (flamingoes)

There are 5 species of flamingoes and 17 identifiedpopulations, most of them in Africa and theneotropics. Only 1 species, the Andean flamingo(Phoenicoparrus andinus) is listed as vulnerable toextinction (IUCN 2002). Of the populations, 3 areknown to be decreasing, 6 increasing and 8 stable(Wetlands International 2002).

3.10.12 Anhimidae (screamers)

There are 3 species and 3 populations within thisfamily. None of the species is listed as threatenedby IUCN, but 2 of the populations are decreasing,while 1 is stable (Wetlands International 2002).

3.10.13 Anatidae(ducks, geese and swans)

There are 164 species and 462 identified popula-tions within this family. With regard to theirconservation status, IUCN lists 25 freshwater-dependent species as threatened and 5 as extinct.The extinct species include the Mauritian shelduck,the Mauritian duck, the Amsterdam Island duck,the Réunion shelduck and the Auckland Islandmerganser. There is also an additional marinespecies that has gone extinct, the Labrador duck.Among the threatened species, there are 5 criticallyendangered, three of which are probably extinct;


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these include the Pink-headed duck (Rhodonessacaryophyllacea), the Madagascar pochard (Aythyainnotata), and the Crested shelduck (Tadornacristata). The critically endangered Campbell Islandteal from New Zealand (Anas nesiostis) has a stablepopulation, while the Brazilian merganser (Mergusoctosetaceus) has a declining population (WetlandsInternational 2002). There are also 9 duck speciesconsidered endangered by IUCN, all of them withdeclining populations; these are the Madagascarteal (Anas bernieri), the Brown teal (Anas chlorotis),Meller’s duck (Anas melleri), the Hawaiian duck(Anas wyvilliana), the Swan goose (Anser cyg-noides), the White-winged wood duck (Cairinascutulata), the Blue duck (Hymenolaimus mala-corhynchos), the Chinese merganser (Mergus squa-matus) and the White-headed duck (Oxyuraleucocephala) (IUCN 2002). Finally there are 11species of freshwater ducks listed as vulnerable toextinction. Of the vulnerable species, the AucklandIsland teal in New Zealand has a stable population,while the Laysan duck found in the HawaiianIslands has an increasing population. The remain-ing vulnerable species, however, all have decliningpopulations (IUCN 2002).

Looking at trend data for all duck populations,not just the threatened species, there are 130 decreas-ing populations, 75 increasing populations, and 121stable populations (Wetlands International 2002).

3.10.14 Pedionomidae (plains-wanderer)

This is a single-species family. The Plains-wanderer(Pedionomus torquatus) is a species endemic to east-ern Australia and although considered a grasslandspecies it is highly dependent on water. It is classi-fied as endangered by IUCN due to its small anddeclining population (IUCN 2002). The majorthreats to the species are the expansion of agricul-ture, the introduction of alien invasive species andland-based water pollution. The single populationof plains-wanderer is decreasing with an estimatedpopulation between 2,500 and 8,000 birds (WetlandsInternational 2002).

3.10.15 Gruidae (cranes)

The 15 extant crane species are widely distributedthroughout the world. They can be found in allcontinents except Antarctica and South America.They inhabit a wide range of climates from habi-tats in northern latitudes, like the Asian tundra, tothe tropical regions of the world. East Asia is themost species-rich region, with 7 species of cranesoccurring on a regular basis. The Indian subconti-nent follows with 5 species occuring during theyear. Africa has 4 species year-round, with 2 addi-tional species during wintering periods (Meine andArchibald 1996). There are 49 identified popula-tions of cranes, many of which are closely moni-tored because of their threatened status.

Cranes are among the world’s most endangeredfamilies of birds, with 9 species listed as threatenedby IUCN. The Siberian crane is critically endangered.The major threat to this species is habitat loss, in par-ticular the destruction and degradation of wetlandsin its passage and wintering grounds. The rich mud-flats of Poyang Lake in China, constitutes its majorwintering site, holding 95% of the population. Thisseasonal lake depends on annual flooding from theYangtze River. The Three Gorges Dam, which haschanged the hydrological regime of the lake, poses amajor threat to the species. The Red-crown craneand the Whooping crane are both considered endan-gered, while the Sarus, Wattled, Hooded, Black-necked, Blue, and the White-naped cranes are alllisted as vulnerable to extinction (IUCN 2002).

Information is available for 43 out of the 49identified populations. Of these, 9 populations areincreasing, 14 are stable and 20 are decreasing(Wetlands International 2002).

3.10.16 Aramidae (limpkins)

This is also a single-species family with 4 identifiedpopulations. Limpkins are found in the WesternHemisphere. There is only information for one ofthe populations in South America, which seems tobe stable (Wetlands International 2002).


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3.10.17 Rallidae(rails, gallinuls and coots)

There are 154 species of rails, gallinuls and coots,and 352 identified populations. The availableinformation on population trends indicates thatthere are 30 extinct, 63 decreasing, 8 increasing,and 25 stable populations (Wetlands International2002). In terms of their conservation status, IUCNlists 7 species as extinct, 1 as critically endangered,7 as endangered, and 6 as vulnerable (IUCN2002). The extinct species include the Red rail(Aphanapteryx bonasia), the Rodrigues rail(Aphanapteryx leguati), the Mascarene coot (Fulicanewtoni), Dieffenbach’s rail (Gallirallus dieffen-bachia), the Tahiti rail (Gallirallus pacificus), theLord Howe swamphen (Porphyrio albus), and theLaysan crake (Porzana palmeri). Madagascar’sOlivier’s crake (Amaurornis olivieri) is the onlyspecies listed as critically endangered, while theendangered species include the Zapata rail(Cyanolimnas cerverai), the Rusty-flanked crake(Laterallus levraudi), the Junín rail (Laterallustuerosi), the Bogotá rail (Rallus semiplumbeus), thePlain-flanked rail (Rallus wetmorei), the White-winged crake (Sarothrura ayresi), and the Slender-billed flufftail (Sarothrura watersi). Finally, the 6vulnerable species are the Brown wood-rail(Aramides wolfi), the Asian yellow rail or Siberiancrake (Coturnicops exquisitus), the Hawaiian coot(Fulica alai), the Rufous-faced crake (Laterallusxenopterus), Woodford’s rail (Nesoclopeus wood-fordi), and the Austral rail (Rallus antarcticus).

3.10.18 Heliornithidae (finfoots)

This small family of odd aquatic birds is distrib-uted in the tropical regions of the world. There are3 species—each in a monotypic genus—and eachfills a niche in the major tropical regions of theworld. Seven distinct populations have beendescribed. There is only 1 species threatened, theAsian finfoot (Heliopais personata), which is classi-fied as vulnerable (IUCN 2002). This species is

found in South and Southeast Asia, where the lossof wetland habitat is causing a decline in the pop-ulation. Trend information is only available forone other population, the African finfoot popula-tion in Angola, which is also in decline (WetlandsInternational 2002).

3.10.19 Eurypygidae (sunbitterns)

The Sunbittern is a water-edge bird found in theNeotropics, from Guatemala to the Pantanal regionof southern Brazil and Paraguay. There is only1 species within the family and 3 identified and dis-tinct populations. There is no population trendinformation and the species is not listed as threat-ened by IUCN.

3.10.20 Jacanidae (jacanas)

There are 8 species and 17 populations of jacanas.Information on population trends is available for4 populations. The populations of Madagascar andSoutheast Asia are both declining, while the one inWestern Colombia and Venzuela and in Sub-Saharan Africa are stable (Wetlands International2002). There are no Jacanidae species listed asthreatened by IUCN.

3.10.21 Rostratulidae (painted-snipes)

The painted-snipes are a small family of shore-birds. The family is composed of just two species:the Greater painted-snipe (Rostratula benghalen-sis) distributed over the warmer parts of the OldWorld, including sub-Saharan Africa, tropical Asia,and eastern Australia, and the South Americanpainted-snipe (Nycticryphes semicollaris) which isfound throughout the southern third of SouthAmerica. There are 4 populations of painted-snipes, however, information on trends is onlyavailable for the Eastern Australian population,which is decreasing (Wetlands International 2002).There are no species listed as threatened withinthis family.


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3.10.22 Dromadidae (crab plover)

The crab plover is a wader of tidal mudflats fromthe NorthWest Indian Ocean, to the Red Sea, andthe Persian Gulf where it breeds. There is only onespecies and one population (Dromas aredeola). Thespecies is not threatened and its stable population isestimated at 60,000-80,000 individuals. The popu-lation’s non-breeding range extends to areas incoastal East Africa to Madagascar, and from coastalPakistan to West India.

3.10.23 Haematopodidae (oystercatchers)

The Oystercatchers are a small family of shorebirdsthat have specialized bills for dealing with oysters,mussels, and limpets. There are 12 species and 21distinct populations of oystercatchers. One speciesof oystercatcher, the Canary Islands black oyster-catcher (Haematopus meadewaldoi), has becomeextinct and 1 species, the Chatham Island oyster-catcher (Haematopus unicolor), is classified as endan-gered (IUCN 2002). Trend information is onlyavailable for 8 populations; five of which are increas-ing while 3 are stable (Wetlands International 2002).

3.10.24 Ibidorhynchidae (ibisbill)

This family has a single species, the Ibisbill(Ibidorhyncha struthersii). It is a unique waderinhabiting shallow, stony rivers at high-altitudes.The species is distributed across the central Asianhighlands from Kazakhstan to Northwest Chinaand south to northern India, including theHimalayan valleys and Tibetan Plateau. The speciesis not listed as threatened and information on itspopulation is not available.

3.10.25 Recurvirostridae(stilts and avocets)

There are 10 species and 25 populations of stiltsand avocets in all regions of the world. There isonly one species listed as threatened, New Zealand’s

black stilt (Himantopus novaezelandiae), which isclassified as critically endangered. Despite 20 yearsof intensive conservation and captive breedingefforts, this species remains one of the most threat-ened shorebirds in the world. Its current popula-tion is estimated at only 40 birds. The annualrelease of substantial numbers of captive-bred birdsand predator control has probably prevented itfrom becoming extinct in the wild, but the num-bers and productivity of wild pairs still urgentlyneed to be increased (IUCN 2002). In terms oftheir population trends, there are 8 stable popula-tions, 4 increasing, and 2 decreasing (WetlandsInternational 2002).

3.10.26 Burhinidae (thick-knees)

The thick-knees are a small family of birds that arepredominantly terrestrial. There are 9 species and 25identified populations. None of the species is classi-fied as threatened by IUCN. Data on populationtrends are only available for 5 populations, all ofwhich are decreasing (Wetlands International 2002).

3.10.27 Glareolidae(coursers and pratincoles)

This family of birds includes 17 species, with 46distinct populations restricted to the Old World.Some of the species in this family, the coursers, aregenerally restricted to short-grass plains or deserts,often far from water. However most pratincoles arewater edge birds inhabiting muddy margins oflakes or estuaries. The only species within thisgroup listed as threatened by IUCN is Jerdon’scourser (Rhinoptilus bitorquatus), which is criticallyendangered; this species is considered terrestrial(IUCN 2002). There is only trend informationavailable for 12 out of the 46 populations, of which4 are freshwater-dependent birds. These include theBlack-winged pratincole population that breeds inRomania, Ukraine, southwestern Russia, andKazakhstan, which is declining; the Madagascarpranticole population which is declining, the Black


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Sea and eastern Mediterranean breeding popula-tion of Collared pranticoles, which is also declin-ing; and the western Mediterranean breedingpopulation of Collared pranticoles, which is stable.

3.10.28 Charadriidae (plovers)

The plovers include 67 species and 156 distinct pop-ulations. There are 31 plover populations decreas-ing, 12 increasing, and 18 that are stable (WetlandsInternational 2002). Several freshwater specieswithin this family are listed as threatened by IUCN.These include one critically endangered species, theJavanese lapwing (Vanellus macropterus); one endan-gered species, the Saint Helena plover (Charadriussanctaehelenae), and two vulnerable species, theWrybill (Anarhynchus frontalis) and the Pipingplover (Charadrius melodus) (IUCN 2002).

3.10.29 Scolopacidae(snipes, sandpipers and phalaropes)

Sandpipers are a highly diverse family, whichincludes some waterbirds but also ground-dwellingbirds like the snipes and woodcocks, and highlypelagic birds like the Red phalarope. There are 90species and 221 populations within the sandpiperfamily. In terms of their conservation status thisfamily has 10 species classified as threatened byIUCN and two that have already gone extinct. Notall the species considered threatened are strictlyfreshwater species. Most inhabit grasslands, tundraor agricultural lands, and some, like the wood-cocks, are considered terrestrial.

The 2 extinct species are the White-wingedsandpiper (Prosobonia ellisi) and the Tahitian sand-piper (Prosobonia leucoptera). There are 2 species,the Eskimo curlew (Numenius borealis) and theSlender-billed curlew (Numenius tenuirostris) thatare considered critically endangered. Among thespecies classified as endangered there are 2 pre-dominantly terrestrial species, the Moluccan wood-cock (Scolopax rochussenii), and the Sharp-billedsandpiper (Prosobonia cancellata), and 1 that is

considered a freshwater species, the Spotted green-shank or Nordmann’s greenshank (Tringa guttifer).The Spotted greenshank, found throughout Asia,has a very small, declining population as a result ofthe development of coastal wetlands throughout itsrange, principally for industry, infrastructure proj-ects and aquaculture (IUCN 2002). Finally thereare 5 vulnerable species. These include theChatham Island snipe (Coenocorypha pusilla), theSpoon-billed sandpiper (Eurynorhynchus pygmeus),the Wood snipe (Gallinago nemoricola), the Bristle-thighed curlew (Numenius tahitiensis), andthe Amami woodcock (Scolopax mira) (IUCN2002). There are 51 decreasing populations, 12 thatare increasing and 43 that are stable (WetlandsInternational 2002).

3.10.30 Thinocoridae (seedsnipes)

Seedsnipes comprise a small family of birdsadapted to open habitats in South America. Thefamily is comprised of 4 species and 10 distinctpopulations. There is no information on popula-tion trends and none of the 4 species is listed asthreatened by IUCN.

3.10.31 Laridae (gulls)

Gulls comprise a large family of shorebirds, con-taining 52 species and 103 identified populations.Gulls are generally found along shorelines aroundthe world, except in some tropical regions, butbecause of their high adaptive capacity they alsooccupy many man-made habitats. Most species aremigratory to some extent. They are gregarious andnot particularly territorial animals found usually inlarge numbers. There are 9 populations that aredecreasing, 23 that are increasing, and 15 that arestable (Wetlands International 2002). In terms oftheir conservation status there are 6 species listedas vulnerable to extinction by IUCN, but nonelisted as endangered or critically endangered. Thevulnerable species include Olrog’s gull (Larusatlanticus), the Black-billed gull (Larus bulleri),


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the Lava gull (Larus fuliginosus), the Relict gull(Larus relictus), the Chinese black-headed gull orSaunders’s gull (Larus saundersi), and the Red-legged kittiwake (Rissa brevirostris) (IUCN 2002).

3.10.32 Sternidae (terns)

Terns are slim and graceful waterbirds, related togulls. In fact, most authors place gulls and ternswithin the same family, Laridae. However, we havefollowed the nomenclature set forth by WetlandsInternational (2002), which considers terns as aseparate family. There are 45 species of terns and173 distinct populations. In terms of populationtrends, there are 23 populations decreasing, 11increasing, and 23 that are stable (WetlandsInternational 2002). Only 1 species within thisgroup, the Chinese crested tern (Sterna bernsteini)is listed as critically endangered by IUCN, another,the Black-fronted tern (Chlidonias albostriatus), islisted as endangered (IUCN 2002).

3.10.33 Rhyncopidae (skimmers)

The skimmers are a small family (3 species) of spe-cialized shorebirds found in North and SouthAmerica, Africa, and India. There is 1 species ineach continent; the Black skimmer (Rhynchops

niger) found in the Western Hemisphere with 4distinct populations, the African Skimmer(Rhynchops flavirostris) with 2 populations, and theIndian skimmer (Rhynchops albicollis) with a sin-gle population. The African and Indian skimmerpopulations are both decreasing, while 1 popula-tion of Black skimmers in South America is stableand another in the United States is increasing(Wetlands International 2002). The Indian skim-mer is considered vulnerable to extinction byIUCN. The major threat is degradation of riversand lakes (IUCN 2002).

3.10.34 Waterbirds Population TrendsSummary by Geographic Region

and Flyways

The information on waterbird population trendsby geographic region presented below is from the3rd Edition of the Waterbirds Population Estimates(Wetlands International 2002). The geographicregions correspond to the six regional groupingsof countries under the Ramsar Conventionon Wetlands.

The trends in waterbird populations are bet-ter known in Europe, North America and Africathan in Asia, Oceania, and the Neotropics. Theimproved knowledge of waterbird populations in


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Table 10. Waterbird Population Trends by Geographic Region

Geographic Region Population Trend Number of Populations

No. No. No. No. With Lacking TotalStable Increasing Decreasing Extinct Known Trend Trend Number

Africa 141 62 172 18* 384 227 611

Europe 83 81 100 0 257 89 346

Asia 65 44 164 6 279 418 697

Oceania 51 11 42 28 138 241 379

Neotropics 100 39 88 6 234 306 540

North America 88 62 68 2 220 124 344

Global Total1 404 216 461 60 1,138 1,133 2,271

1 Global totals do not equal the sum of the column because a population is often distributed in more than one Ramsar Region.

* Most extinctions in Africa have been on associated islands.


Africa is apparent if compared to previous water-bird assessments and reflects the efforts byWetlands International and BirdLife Internationalin the 1990s to survey and assess waterbird popu-lations in this continent. Overall, however, thenumber of populations for which there is no trendinformation remains high; therefore the numberspresented in Table 10 have to be interpreted withcaution. In every region, the proportion of popu-lations in decline exceeds those that are increas-ing. Nonetheless, it is important to note thatdetailed information is more readily available forsmaller populations, which are more likely to bein decline. Asia and Oceania are the regions ofhighest concern for the conservation of water-birds. Both regions have the highest number ofknown populations with decreasing trends, whileat the same time trend information is lacking formost of the populations in these regions. Oceaniaalso has the largest percentage of extinct popula-tions, mostly small island endemic populations. InAfrica and the Neotropics more than twice asmany known populations are decreasing thanincreasing. In Europe and North America water-bird population numbers seem to be more equallydistributed among the 3 categories (stable, increas-ing and decreasing). But at the global level, 41%of known populations are decreasing, 36% are sta-ble and 19% are increasing. There is an urgentneed to reverse these trends and increase the con-servation efforts for freshwater-dependent birds.

Whilst analysis of population status bygeopolitical region is informative, status assess-ment of biogeographical populations using thesame migratory flyways can provide clearerinsights into where and why certain populationsare under threat or of special concern, as an essen-tial basis to guide conservation actions. However,detailed analyses at the biogeographic populationlevel for most waterbird taxa for the different fly-ways are not readily available. The following sec-tion presents a trend analysis of the wader

(shorebird) species6 with migratory populationsusing three African-Eurasian flyways7, as an exam-ple of a biogeographic trend assessment. This typeof analysis could be done for other regions of theworld and other taxa based on existing populationtrend data.

Stroud et al. (2003) have assessed the changein the overall status of migratory wader popula-tions since the late 1980s by comparing currentinformation with trend estimates from the 2ndEdition of Waterbird Population Estimates (Roseand Scott 1997). The following section presentsthe results from this analysis. Almost all these pop-ulations are dependent on inland water systemsfor at least part of their annual cycle.

Of the 131 wader populations of 55 belong-ing to species which use these three African-Eurasian flyways population sizes were estimatedfor 125 populations and trend assessments madefor 72 populations belonging to 32 species. Ofthese 72 populations, nine are increasing, five arestable or increasing, 15 are stable, two are stable ordecreasing and 27 are decreasing. Overall, almostfour times as many populations are decreasingthan increasing.

Direct comparison of more recent (1990s)with earlier (1980s) trends was possible for only32 of these populations. Of these, the status of 17is unchanged (or probably unchanged) since themid-1980s. Three populations, all on the EastAtlantic flyway, are undergoing a long-termincrease; 6 populations are long-term stable and 8populations are in long-term, and sometimes seri-ous, decline (see Table 11).

Based on this analysis, Stroud et al. (2003)concluded that there has been little change inoverall status of migratory waders in Africa-Eurasia over the last 15-20 years. However, thisoverall pattern masks substantial changes in thestatus of individual populations. For some popu-lations, notably those on the East Atlantic flyway,status is improving. However a significant num-


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6 Species in families Dromadidae, Haematopodidae, Recurvirostridae, Burhinidae, Glareolidae, Charadriidae and Scolopacidae.7 East Atlantic; Black Sea/Mediterranean; and West Africa/East Africa flyways.


ber of other populations, spread across all flyways,are in decline or have a deteriorating status (fromincreasing to stable).

In addition to populations in decline, popula-tions can also be of conservation concern if they aresmall or if their status is deteriorating (fromincreasing to stable or from stable to decreasing).Further analysis using these criteria show that of thetotal of 115 populations of migratory wader speciesin Africa-Eurasia, 31 can be regarded as being atrisk, because their populations are in decline and/orare small (see Table 11). A further 3 populations arealso of concern since their population status hasdeteriorated from previous trend estimates, and 8populations appear to be in long-term decline.

Of the populations at risk, 7 can be classifiedas being of major conservation concern becausethey have a small population of less than 25,000birds, which is in decline. The best documentedcase is the Slender-billed curlew, which is now onthe verge of extinction. The other 6 species are theSociable plover with a rapidly declining popula-tion of only about 2,000 birds, the Baltic-breedingpopulation of schinzii dunlin, the Black Sea/EastMediterranean population of Collared pratincole,the Black Sea/East Mediterranean population ofKentish plover, and the two small resident popu-lations of Stone curlew in the Canary Islands.

Five further populations, all on the WestAsian/East African flyway, are of concern as theirpopulations are small (<25,000 birds), but there isno information on trends (see Table 11).Establishing the status of these populations shouldbe considered a priority.

Only four small (<25,000 birds) populationsof African-Eurasian migratory wader species areconsidered stable or increasing. These are the WestAfrican/East African population of Oystercatcher,West Mediterranean Collared pratincole andAvocets of the West Asian/East African andSouthern African populations (see Table 11).

Also of conservation concern are 19 largerpopulations that are declining or possibly declin-ing (see Table 11). Of these, the Kentish plover, Bar-

tailed godwit, and canutus red knot populations onthe East Atlantic flyway are of particular concernas they have undergone sharp declines. Likewisethe Black-winged pratincole, breeding in West andCentral Asia, is undergoing a significant decline.

Comparison of the characteristics of popula-tions of conservation concern provides someinsights into the possible reasons for decline or dete-riorating status. Many of the most severely declin-ing populations breed in the arid and semi-aridareas of the Middle East, west and central Asia, andthe Mediterranean Basin, or primarily in Europeanwet grassland habitats maintained through agricul-tural practices. Continuing loss of steppe breedinghabitat through intensification of agriculture andirrigation schemes, coupled with increasing fre-quency and severity of drought and desertification,are considered as likely drivers behind the decline ofbreeding populations such as those of the Sociableplover and Black-winged pratincole.

According to Stroud et al. (2003) the reasonsfor the decline of certain populations on the EastAtlantic flyway (Kentish plover, Bar-tailed godwit,and canutus red knot) are not yet clear. Because thedeclining populations are observed in differentbreeding areas, changes occurring in the breedinggrounds seem unlikely. On the other hand, if thecause lies on wintering grounds it is unclear whythese populations are in decline while other popu-lations wintering in the same area of coastal WestAfrica are either stable or increasing (e.g. Curlewsandpiper). Further assessment of possible causes ofdecline, should be a priority for the long-term con-servation of these migratory species and the habi-tats upon which they depend, perhaps focusing onthe ecological status of migratory staging areas.

Likewise, the reasons for the increase of somepopulations are also unclear. None of these are inthe West Asia/East African flyway, and most (sixpopulations) are on the East Atlantic flyway. Someof the increasing populations use the same breed-ing and overwintering areas as other populations indecline. Different increasing populations use almostall parts of the wintering range on the flyway, and


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come from different arctic and sub-arctic breedingareas (although none are wholly temperate zonebreeders). The possibility of a link between popu-lation increase and different migratory strategiesand/or extent of dependence on particular migra-tory staging areas requires further investigation.

3.11 MAMMALS

Although all terrestrial mammals depend on fresh-water for their survival and many feed and drinkin rivers and lakes or live in close proximity tofreshwater ecosystems, only a small number of


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Table 11. Populations of African-Eurasian Migratory Wader Species that are ofConservation Concern

Population East Black Sea/ West Asian/ Status Atlantic Mediterranean East African Africaand Trend flyway flyway flyway residents

Small declining populations:

Dunlin Collared pranticole Sociable plover Stone curlew[Kentish plover] (2 populations)*Slender-billed curlew

Small populations with unknown trend:

Black-winged stilt Greater sand plover (Black Sea/East Mediterranean and South-west Asia populations)WhimbrelGreat knot

Small populations not in decline:

Collared pranticole Oystercatcher AvocetAvocet

Large declining populations:

Golden plover Stone curlew *Black-winged *Kentish plover (2 populations) PranticoleBar-tailed godwit *Common snipe [*Great snipe]Common redshank [*Jack snipe] [Eurasian curlew](2 populations) *Black-tailed godwit [Ruff]Red knot (2 populations)Dunlin [*Wood sandpiper]

[Little stint]

Populations with deteriorating status (formerly stable, currently declining):

Red knot [Little stint]

Populations with deteriorating status (formerly increasing, currently stable):

Black-winged stiltBlack-tailed godwitBar-tailed godwit

Source: Stroud et al. (2002)

Notes: Species in square brackets […] are those for which the population trend is possible but uncertain. Species in italic text arethose that are in strong or very strong decline. Populations in long-term decline (i.e. also cited as declining in Rose and Scott(1997) are indicated with an asterisk (*)


mammals are considered aquatic or semi-aquatic.The following paragraphs provide a compilation ofaquatic and semi-aquatic mammals by taxonomicorder and geographic region. The mammals pre-sented spend a considerable amount of time infreshwater and usually live in the riparian vegeta-tion close to rivers, lakes, lagoons, ponds, etc. or inmarshes and swamps, although they may forageand sleep on land.

3.11.1 Order Monotremata (monotremes)

One of the better-known and probably the oddestfreshwater mammal is the Duck-billed platypus(Ornithorhynchus anatinus). It is the single specieswithin its taxonomic family and one of the 3 speciesof living monotremes in the world. This group con-sists of egg-laying mammals, and the eggs are incu-bated outside the mother’s body (Nowak 1991).The platypus lives in streams, lakes, and lagoons ineastern Australia and Tasmania. Historically, theplatypus was hunted for its pelt, and consequentlyalmost extirpated from its range. Government con-servation strategies have allowed the species torecover, although river fragmentation from dams,habitat degradation from pollution and irrigationschemes, and entrapment with fishing gear still posea threat to the species (Nowak 1991).

3.11.2 Order Marsupialia (marsupials)

In South America, there is a semi-aquatic marsu-pial, the water opossum (Chironectes minimus).This is the only marsupial adapted to semi-aquaticlife, and the only opossum with webbed feet. Bothsexes have a well-developed pouch, but, as opposedto other pouched mammals, in the female wateropossum, the pouch opens towards the tail-end ofthe animal and a sphincter muscle closes the pouchto create a watertight compartment for the young(Emmons 1997). The species is categorized byIUCN as near threatened (IUCN 2002). The mainreason for this conservation status is the inferredreduction in the population based on the decline

in the quality of its habitat, mostly due to pollution(Ojeda and Giannoni 2000). Water possums live inand near rivers and stream, all over the neotropics,but there is very little information on their status,population trends, or threats to the species.

3.11.3 Order Chiroptera (bats)

Although many species of bats are associated withfreshwater, only one group of fishing bats isincluded in this summary. These are the bulldogbats or fishing bats belonging to the familyNoctilionidae. Two species from the genus Noctiliomake up this family: the lesser bulldog bat(Noctilio albiventris) and greater bulldog bat(Noctilio leporinus). Both species feed on aquaticinsects, and N. leporinus eats fish, frogs, and crus-taceans as well. Fish-eating in bats are thought tohave evolved from catching floating or swimminginsects off the water. To capture fish, these bats flywithin 20-50 cm of the water surface over ponds,rivers, strems and saltwater lagoons listening forprey. They use echolocation to detect ripples onthe water surface made by swimming fish, crus-taceans or amphibians. They then drag their hindclaws, which are unusually large and sharp,through the water and catch the fish. Noctilionidsare relatively large bats, often brightly colored(varying from bright red or orange in males togray-brown in females) and with strong musclestructure. If knocked into the water, fishing batscan swim using their wings as oars, and are capa-ble of taking flight from water (Animal DiversityWeb 2002). They are found in tropical and sub-tropical parts of the Central and South America,including the Greater and Lesser Antilles. Theirrange extends from Southern Mexico to NorthernArgentina and Southeastern Brazil. Both speciesare widespread and common.

3.11.4 Order Insectivora (insectivores)

This group of species includes the water-dependentshrews. In North America there are several species


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of water shrews. Two of these (Sorex palustris andSorex bendirii) extend throughout most of Canada,down to Northeast California, Utah, through theGreat Lakes region and from New England all theway down the Appalachian Mountains to NorthCarolina. There is also an isolated population in theArizona mountain region. One particular species isalso found in Glacier Bay, Alaska (Sorex alaskanus)(Whitaker 1991). Water shrews are found alongstreams and lakes, or in wet forests. Many othershrew species also inhabit moist forests, or are closeto streams, marsh, and swamp areas but are notconsidered water shrews. The fourth NorthAmerican water-dependent shrew is the Swampshort-tailed shrew (Blarina telmalestes), which isfound in Virginia (Whitaker 1991). These speciesare not listed as threatened by IUCN.

In Europe and Asia, there are also severalspecies of water shrews. Three species belonging tothe genus Neomys are found in Western andSouthern Europe, Western Siberia and PacificSiberian coast, Armenia and Georgia. Other speciesinclude the Elegant or Tibetan water shrew(Nectogale elegans), and six species of Asiatic watershrews (Chimarrogale ssp.) that inhabit streams inmountain regions at altitudes of up to 3300 m(Stone 1995). The Tibetan water shrew is distrib-uted in mountain streams from southwest Chinato southeast Tibet, and the Himalayas to easternNepal (Stone 1995). Although very limited infor-mation is available on these species, two of them,the Malayan and the Sumatran water shrew areconsidered critically endangered, while a thirdspecies, the Borneo water shrew is consideredendangered (IUCN 2002).

A particular and unique group of aquaticinsectivores found in Europe are the desmans.There are two species Desmana moschata or Russiandesman, which inhabits rivers in southwesternRussia, Belarus, Kazakstan, and Ukraine and thePyrenean desman (Galemys pyrenaicus) found inthe Pyrenees and the mountain regions of north-ern-central Spain, and northern Portugal (Nowak1991). Both species are listed as vulnerable to

extinction by IUCN (2002). The Russian speciesinhabits slow-flowing rivers, lakes, and ponds andis semi-aquatic, while the Pyrenean species is strictlyaquatic and requires fast-flowing streams. The totalpopulation of Russian desmans is estimated to bebetween 40,000 and 50,000 individuals, while thepopulation for the Pyrenean desman is not known(Nowak 1991; Stone 1995). The major threats to theRussian desman are hunting, water pollution,creation of impoundments, clearance of riparianvegetation, entanglement in fishing nets and com-petition for breeding sites with other exotic species(e.g. nutria and muskrat). For the Pyrenean speciesthe major threats are water pollution and habitatfragmentation. Other threats are direct persecutionfrom fishermen who incorrectly believe this speciesto be a threat to fish stocks, especially trout, or fromeager collectors (Stone 1995). Finally the escape ofNorth American mink from fur farms in northernIberia is thought to have a negative impact on thespecies (Stone 1995).

A unique and threatened group of aquaticshrews found in Africa are the otter shrews. Ottershrews are the only survivals of a prehistoric groupof animals that used to be widespread. They areclosely related to the tenrecs, which are only foundin Madagascar. There are 3 species of otter shrews,all with a very restricted distribution within theCongo basin, and west-central Africa (Kingdon1997). The largest one, the Giant otter shrew(Potamogale velox) is found from Nigeria to west-ern Kenya and southwards to central Angola andnorthern Zambia. The species inhabits slow flow-ing streams, forest pools, and stream banks inmountain areas and is endangered according to theIUCN Red List (IUCN 2002). Because it dependson its sight for hunting prey, soil erosion caused bydeforestation and loss of riparian habitat are majorthreats to the species. Water turbidity from silta-tion is especially a problem in Cameroon (IUCN2002). Other important threats affecting the speciesare hunting for its skin, entrapment with fishinggear, and fragmentation of the population (IUCN2002). The other two species of otter shrews, the


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Mount Nimba and Ruwenzori otter shrews, aremuch smaller and also endangered. They are bothbeing heavily affected by water pollution especiallyfrom mining operations. The Mount Nimba ottershrew is found in Cote d’Ivoire, Guinea and Liberiaand the Ruwenzori otter in Congo and Uganda(IUCN 2002).

In Madagascar there is a group of semi-aquaticinsectivores called ternecs. Some of the Malagasytenrecs, like the 3 species of rice tenrecs, are usuallyfound in marsh areas and on the banks of rice pad-dies, where they burrow. Finally the Aquatic orWeb-footed tenrec (Limnogale mergulus) from east-ern Madagascar is considered to be endangered(2002). The major threat is siltation and soil ero-sion caused by deforestation because the speciesrequires clear, fast flowing water (Nowak 1991).

3.11.5 Order Lagomorpha(rabbits and hares)

The semi-aquatic freshwater mammals within thisorder are primarily found in North America. Theseare the Marsh and Swamp rabbits, Sylvilgus palus-tris and Sylvilgus aquaticus (Whitaker 1991). Thesespecies live in swamps, marshes, lake borders andcoastal waterways. Marsh rabbits are found in theSoutheast of the U.S. (Florida and up the coast toSoutheast Virginia). Swamp rabbits are found fromeastern Texas and Oklahoma, to South Illinois andNorth Georgia (Whitaker 1991). Neither species isconsidered endangered by IUCN, although a sub-species of marsh rabbit, the Lower Keys marsh rab-bit, has been listed as endangered since 1990 by theU.S. Fish and Wildlife Service (USFWS 2002).

There is also a riverine rabbit in South Africa(Bunolagus monticularis). This species, habituated toseasonal rivers, is one of the most threatened speciesin South Africa. It inhabits dense riverine scrubalong seasonal rivers in the central Karoo Desert ofSouth Africa’s Cape Province. This species is classi-fied as endangered (IUCN 2002). The major threatto the species is habitat loss from conversion to agri-culture, firewood collection and overgrazing by

sheep. Other threats include hunting with dogs, pre-dation from uncontrolled dogs, trapping, and damconstruction, which alters the river flow. There areseveral organizations involved in the conservation ofthe species including WWF-South Africa, CapeNature Conservation, Northern Cape NatureConservation, and the Society for the Conservationof Species and Populations of South Africa (RiverineRabbit Conservation Project Web Site 2002).

3.11.6 Order Rodentia (rodents)

Some of the best known semi-aquatic mammalsare the beavers. The North American beaver(Castor canadensis) is found only in North Americaand it is one of the two species within theCastoridae family. It extends throughout freshwa-ter habitats all over North America with the excep-tion of Florida, Nevada and southern California(Whitaker 1991). The other beaver species (Castorfiber) is found in Europe and Asia, except for theMediterranean region and Japan. These semi-aquatic mammals are among the largest rodents inthe world. Both beaver species used to be widelydistributed but their populations declined drasti-cally from hunting for the fur trade and the mod-ification and fragmentation of rivers (Nowak1991). By early 1900 only a few small and scatteredpopulations of beavers remained in Europe andNorth America. Some conservation measures inboth regions, including introductions, have allowedthe species to recover especially in Scandinavia andsome parts of North America. Currently the majorthreats to the species are water pollution, wetlanddrainage, and hydroelectric plants (Nowak 1991;Whitaker 1991).

Other groups of rodents that live in freshwa-ter habitats, especially freshwater marshes, are therice rats, muskrats, and water voles. In NorthAmerica there are 2 species of rice rats, the Marshrat (Oryzomis palustris) and the Key or Silver ricerat (O. argentatus) (Whitaker 1991). The firstspecies is found throughout Southeast U.S. andpart of the Mid-Atlantic States, the second one is


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found only in Cudjoe Key, Florida. The NorthAmerican water vole (Arvicola richardsoni) is foundalong upland streams and lakes, from southeasternand southwestern British Columbia, southwesternAlberta, to central and eastern Washington andOregon, North Idaho, North-Central Utah, west-ern Wyoming and western Montana (Whitaker1991). The North American muskrat speciesinclude the Florida water rat (Neofiber alleni) foundin South Georgia and Florida, and the Commonmuskrat (Ondatra zibethicus) found in most ofNorth America, except southern part of theU.S.(Florida through Texas, California and Georgia)(Whitaker 1991). Finally the Nutria (Myocastor coy-pus), which is native to South and Central America,has been introduced to North America and can befound especially in the Southeast, but also in theMid-Atlantic region, in the Great Plains and thePacific Northwest (Whitaker 1991).

The aquatic and semi-aquatic rodents inAfrica include different species of water rats. TheMarsh cane rat (Thryonomys swinderianus) isfound throughout central Africa, parts of westernAfrica and down the coast in east Africa in water-logged valley bottoms with abundant grasses andreeds. This species is not endangered (Kingdon1997). The shaggy swamp rats, which live inswamps, marshes, and wet grassy areas of sub-Saharan Africa, especially at high altitudes (i.e., inmoss bogs) and include 5 species from the genusDasymys (Kingdon 1997). There is very little infor-mation on these species, 3 of which are classifiedas data deficient by IUCN and one, D. montanus asvulnerable to extinction (IUCN 2002). Accordingto Kingdon (1997) the genus requires taxonomicrevision. Other semi-aquatic rodents found inAfrica are the creek rats (5 species of the genusPelomys). These live in marshes, reed beds,lakeshores and mountain bogs in central and east-ern Africa. There are 2 species in these genus foundin Uganda and Rwanda that are considered vulner-able by IUCN because of their restricted distribu-tion and habitat, although information on thesespecies is very limited (IUCN 2002). Finally, there

are 4 species of long-eared marsh rats in Africa inthe genus Malacomys that are found in thick vege-tation near water (Nowak 1991).

The best-known aquatic rodents in Centraland South America are the Capybara (Hydrochaerishydrochaeris) and the Nutria (Myocastor coypus).The Capybara is a large rodent that lives in vege-tated areas near rivers, lakes, ponds, and other wet-lands. It is hunted throughout its range for itsmeat, hide, fat (which is used in medicines), andteeth (for use as ornaments by local populations),and sometimes deliberately killed because it is con-sidered an agricultural pest. The populations inVenezuela and Peru have declined considerably, butit is still common in other areas, and is sometimesraised in ranches for commercial purposes (Nowak1991). The nutria is native to Southern Brazil,Bolivia, Paraguay, Uruguay, Argentina and Chileand lives in marshes, lakeshores, and slow-flowingstreams (Nowak 1991). Its major threat is huntingfor its fur and meat, which continues throughoutits range and seems to have affected the popula-tions in South America. The species has extendedits range through intentional or accidental intro-ductions and is now found in North America, andparts of Europe and Asia, including Japan. In Southand Central America, there are also numerousspecies of semi-aquatic rodents usually called waterrats, swamp rats, water mice, etc. Among thespecies commonly known as water rats there are:• three species from the genus Nectomys, which

are widespread and common throughouttropical areas of Latin America, except for N.parvipes, which is restricted to French Guianaand is critically endangered (IUCN 2002);

• the single species of its genus, Scapteromystumidus, found from southern Paraguay andBrazil to Uruguay and northeastern Argentina;

• the single species Anotomys lenader or Fish-eating rat, from the Andes region north ofEcuador;

• four species of web-footed rats or marsh ratsin the genus Holochilus distributed through-out the wetter areas of South America; and


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• the Andean swamp rat (Neotomys ebriosus),which can be found from central Peru, Boliviato the northern parts of Chile and Argentina(Emmons 1997; Nowak 1991).

South and Central America also have 4 species ofcrab-eating rats (Ichthyomys spp.). Crab eating ratsare always found near freshwater (not salt or brack-ish water) and require clear and fast flowing streams.The species are not very well known, and usuallyfound in small streams in hilly or forested areas.Crab-eating rats have been recorded in the easternslope of the Andes in Ecuador and Peru, the west-ern slope of the Andes from Panama to Ecuador,and in the coastal mountain range in Venezuela(Emmons 1997). One species, I. pittieri, found inVenezuela is vulnerable to extinction (IUCN 2002).

There are also 5 species of water mice inCentral America (Rheomys spp.) and 4 species ofSouth American water mice (Neusticomys spp.) butthere is little information on these species. Allspecies are considered rare or difficult to capture(for further study) and the 4 South Americanspecies found in Peru, Venezuela, and the GuyanaShield, are considered endangered by IUCNbecause of their restricted habitat (Emmons 1997;IUCN 2002).

In Europe there are 2 species of water volesthat have aquatic and non-aquatic populations(Arvicola sapidus and A. terrestris). The aquaticpopulations of A. terrestris are found mostly inWestern Europe, while A. sapidus is only found inFrance, Spain, and Portugal. A. sapidus is classifiedby IUCN as being at lower risk of extinction, butunder the category of “near threatened,” meaningthat the species is close to qualifying for a threat-ened status (Nowak 1991, IUCN 2002).

In Oceania, there are 4 species of beaver rats inthe genus Hydromys, which are large aquatic rats,found in marshes, swamps and other wetland areasfrom Papua New Guinea to Australia and some ofthe South Pacific islands (Nowak 1991). One speciesfrom Papua New Guinea, H. neobrittanicus, is vul-nerable (IUCN 2002). There are also 2 uniquespecies in Papua New Guinea that inhabit riparian

areas along mountain streams, the Mountain waterrat (Parahydromys asper), and the Earless water rat(Crossomys moncktoni), both found at high eleva-tions on the island (Nowak 1991).

3.11.7 Order Carnivora (carnivores)

3.11.7.1 Otters and other mustelids

Although many North American carnivores fish inrivers and lakes, or live in close proximity to fresh-water ecosystems, only a few are characterized asfreshwater-dependent mammals. These include theAmerican Mink (Mustela vison) and the river otter(Lutra canadensis). The Mink is found almost tax-onomic throughout North America, except for themore arid areas ofsouthern California, Arizona,southern Utah and New Mexico, and western Texas.The River otter is distributed throughout most ofCanada and south to northern California and Utah.It is also found in the East from New Foundlandsouth to Florida, with the exception of the Midwest,where is has disappeared (Whitaker 1991).

Another mustelid found in Europe is theEuropean mink (Mustela lutreola). Like theAmerican mink, this species lives in dense vegeta-tion on the banks of rivers, lakes and streams. Thisspecies has been hunted and trapped for its fur forcenturies, its habitat has been heavily affected bydams and canals, as well as water pollution, andmore recently the species has suffered from com-petition from exotic species, particularly from theAmerican mink. The American mink was intro-duced to Europe originally as part of the establish-ment of fur farms. However, individuals quicklyescaped from farms or were accidently released intothe wild, where they adapted very well to theEuropean environment, to a point where they dis-placed and outcompeted the native speciesthroughout much of the continent. It is estimatedthat the European mink only survives in Finland,eastern Poland, parts of the Balkans, south-westernFrance and northern Spain, as well as in Russia,where its population has declined to around 40,000


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(Nowak 1991). The species is considered endan-gered (IUCN 2002).

In Africa there are 4 species of otters: theCongo claw-less otter (Aonyx congica), theCapeclaw-less otter (Aonyx capensis), the Commonor Eurasian otter (Lutra lutra), and the Spot-necked otter (Lutra maculicollis) (Kingdom 1997).All otters in Africa are hunted for their fur andmeat, or because they are perceived by rural com-munities and fishers as competitors for food (fish).Habitat degradation, deforestation, siltation, waterpollution, wetlands drainage, water diversions, andriver fragmentation, have all affected the habitatand distribution of otters in Africa. In addition,entrapment with fishing gear is also a cause of highotter mortality. Otter populations are decliningthroughout Africa (Nel and Somers 1998). How-ever, the current knowledge and understanding ofthe biology, status and distribution of the threesub-Saharan otter species is very poor. The twoclaw-less otters are hunted because of their soft fur.The Congo claw-less otter occurs in central Africa,particularly in the Congo River basin, as well as theforests and wetland areas of Rwanda, Burundi, andsouthwestern Uganda. This species is the leastknown of the three African otter species, and nodetailed ecological study on this species is believedto have been published (Nel 1998). In spite of itsname the Common otter is almost extinct in Africaand considered vulnerable to extinction by IUCN.Its range used to extend from Morocco to Tunisia.Hunting, water pollution, habitat fragmentationand degradation, and siltation of rivers due todeforestation are the main causes for its disappear-ance. The Spot-necked otter requires clear water tohunt. The major threat to this species, which is dis-tributed throughout the wetter parts of central andwestern Africa and parts of South Africa, is theincreased silt load (turbidity) in many Africanrivers resulting from deforestation and agriculturalactivities. Populations are declining throughout itsrange, especially in South Africa, and it is consid-ered vulnerable to extinction (IUCN 2002;Kingdon 1997).

In South and Central America there are 3species of freshwater otters. The Neotropical otter,which is widely distributed from Mexico to north-ern Argentina (Lutra longicaudis), the Southernriver otter or Huillin (Lutra provocax) found insouthern Chile and western Argentina, and theGiant Brazilian otter (Pteronura brasiliensis) foundfrom Venezuela to northern Argentina, and fromthe headwaters of some Amazon tributaries to thePantanal region (Foster-Turley et al. 1990). TheSouthern river otter used to have an extensive dis-tribution from the Cauquenes and CachapoalRivers to the Magellan region in Chile. Its currentpopulation, however, is restricted to just sevenisolated areas from Cautín to Futaleufú. This pop-ulation decline is driven by habitat loss, deforesta-tion, removal of river bank vegetation, river andstream canalization and dredging, dams, andpoaching—especially in southern Chile. Theremaining populations are highly fragmented, andtherefore more susceptible to local extinctions.L. provocax is considered endangered by IUCNand listed in the Chilean Red Data Book ofVertebrates as being in danger of extinction. It isalso listed as endangered in the Argentine NationalWildlife List (IUCN 2002).

The Giant Brazilian otter is the largest of allthe 13 otter species and is endemic to the rain-forests and wetlands of South America. It is knownto inhabit large rivers, streams, lakes and swampsof the lowland areas with gentle flow and oxbowlakes with high fish densities. The distribution ofPteronura brasiliensis has declined dramatically inits former range and estimates suggest that it hasprobably already been extirpated from Uruguayand Argentina. Deforestation, soil erosion, decreaseof prey abundance, over-fishing and illegal hunt-ing of otters are the major threats to the species.Canine diseases, such as parvovirus and distemper,transferred through the domestic stock are also athreat. Finally, mining operations that contaminaterivers and fish with mercury also have a negativeimpact on the species. The species is listed asendangered (IUCN 2002).


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In Europe and Asia, the most widely distrib-uted species is the Eurasian otter (Lutra lutra), butmany populations are declining and today it isconsidered vulnerable to extinction (IUCN 2002).The Eurasian otter has the widest distribution ofall otter species. Its range covers parts of three con-tinents: Europe, Asia and Africa. Originally thespecies was widespread throughout Europe. Littleis known about the original distribution in Africaand Asia. In Europe, otters inhabit many differenttypes of aquatic habitats, including lakes, rivers,streams, marshes, swamp forests and coastal areas.The aquatic habitats of otters have been modifiedand destroyed throughout its range. The buildingof canals, dams, the draining of wetlands, andaquaculture activities have all impacted the otterpopulations negatively. In addition water pollutionand acidification pose major threats, particularlyin western and central Europe. Illegal hunting con-tinues to be a problem in many parts of its distri-bution range. In several European countriespolitical pressure, especially by fishermen, hasresulted in granting of licenses for killing otters(IUCN 2002).

In Asia there are 3 additional species of otters,the Hairy-nosed otter (L. sumatrana), the Smooth-coated otter (L. perspicilata) and the Oriental small-clawed otter (Amblonyx cinereus), which is thesmallest species (Foster-Turley et al. 1990). Little isknown about the biology and distribution of theHairy-nosed otter, which is classified as data defi-cient by IUCN. The Hairy-nosed otter is endemicto Southeast Asia and has been reported from Java,Borneo, Sumatra, Malaysia, Thailand and Indo-china. Major threats to this species are habitatdestruction, depletion of its prey base, and roadkills. The oriental small-clawed otter is found inIndia, the Himalayan foothills, and eastwardsthroughout Southeast Asia to the Philippines(IUCN 2002). It inhabits freshwater and peatswamp forests, rice fields, lakes, streams, reservoirs,canals, mangroves and coastal areas. Like withother otter species, the major threat is habitatdegradation from agriculture, development activ-

ities, aquaculture, water pollution, overexploitationof fish, and siltation of streams due to deforesta-tion. Increased influx of pesticides into the streamsfrom the plantations reduces the quality of thehabitats. The Smooth-coated otter is found fromIraq through South and Southeast Asia and south-ern China. In general it inhabits large rivers andlakes, peat swamp forests, mangrove forests alongthe coast and estuaries, and even rice paddies inSoutheast Asia. The major threats are loss of wet-land habitats due to construction of large-scalehydroelectric projects, reclamation of wetlands forsettlements and agriculture, reduction in prey bio-mass, poaching and contamination of waterwaysby pesticides. The species is listed as vulnerable toextinction (IUCN 2002).

3.11.7.2 Viverrids

The Marsh mongoose (Atilax paludinosus) lives inrivers and lakeshores throughout the wet areas ofsub-Saharan Africa (Kingdon 1997). The species isstill believed to be widespread and common,although its populations have drastically declinedfrom hunting and habitat loss in the last decades(Nowak 1991). Other mongooses, such as theMalgassy mongoose in Madagascar and the West-Bangal marsh mongoose in India, are howeverendangered (IUCN 2002).

The Otter civet (Cynogale bennettii), foundnear streams and swamps in northern Vietnam,Borneo, Sumatra and the Malay Peninsula (Nowak1991), is also considered endangered by IUCN(2002).The Aquatic genet (Osbornictis piscivora)lives in the shallow headwaters of streams withinforested areas, where the water is clear. It isreported from the upper reaches of the Congotributaries. It is an extremely rare carnivore andlikely to become vulnerable, but not enough infor-mation on the species is available to assess its sta-tus (Kingdon 1997). The Crab-eating mongooseis also a semi-aquatic mammal found in Asia,from Nepal to Thailand and Indonesia (Lekaguland McNeely 1988).


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3.11.7.3 Felines

Two feline species that are strongly associated withwetlands and spend most of their time hunting forfish, amphibians and invertebrates near rivers,swamps, marshes, and mangroves are the Fishingcat (Prionailurus viverrinus) and the Flat-headedcat (Prionailurus planiceps), both species withwebbed toes that allows them to hunt in water. TheFishing cat is found from Pakistan to SoutheastAsia, including Sri Lanka, Sumatra and Java, but itsdistribution is very discontinuous, with presencein some of the Indonesian islands, but absent inmuch of the Malay Penninsula (Nowak 1991;Nowell and Jackson 1996; IUCN 2002). In India,the Fishing cat is found in the valleys of the Gangesand Brahmaputra rivers, and along the upper partof the east coast. In Pakistan, it is mainly foundalong the lower reaches of the Indus River, and inJava it seems to be confined to a few coastal wet-lands. The major threats to the species are habitatloss by human encroachment, conversion of wet-lands for agriculture, clearing of mangroves foraquaculture, and water pollution by pesticides. Areview of the condition of wetlands in Asia for wildcats, for example, shows that half of more than 700wetland sites were highly or moderately threatenedby human activities (IUCN/SSC Cat SpecialistGroup 2002). More field studies and informationis needed on this species. The species is consideredvulnerable to extinction, and it is highly threatenedin some localities such as the south-western coastof India, the deltas of the Irrawaddy, Indus,Mekong and Red Rivers, and in Java, where thefishing cats are “probably on the verge of extinc-tion” (Nowell and Jackson 1996; IUCN/SSC CatSpecialist Group 2002). The species is listed inCITES Appendix II and legally protected over mostof its range (Nowell and Jackson 1996).

The Flat-headed cat is very rare, and not muchinformation on this species particularly in the wildis available. The species is classified as vulnerableto extinction and believed to inhabit areas inMalaysia, Indonesia, Myanmar, Brunei Darussalam,

and Thailand (IUCN 2002). The major threat tothe Flat-headed cat throughout its range is waterpollution, with toxic elements accumulating in thefatty tissue of its prey. Of special concern is pollu-tion by oil, organochlorines, and heavy metals asso-ciated with agricultural run-off and loggingactivities (Nowell and Jackson 1996). In addition,habitat loss and degradation contribute to thereduction of population and put pressure on thespecies. The Flat-headed cat is included on CITESAppendix I. The species is fully protected bynational legislation over most of its range, withhunting and trade prohibited in Indonesia,Malaysia, Myanmar and Thailand, and huntingregulated in Singapore (Nowell and Jackson 1996).

3.11.7.4 Freshwater seals

There are several species and subspecies of fresh-water seals belonging to the family Phocidae alsoknown as true seals or earless seals. These includethe Lake Baikal seal (Phoca sibirica) and the LakeLadoga seal in Russia and the Lake Saimaa seal inFinland. The two later are subspecies of P. hispida(P. h. ladogensis and P. h. saimensis) (Reijnderset al. 1993).

The Lake Baikal seal is the only pinniped thatis restricted to freshwater and is found only in LakeBaikal, Russia. It was heavily hunted in the first partof the century for meat, oil and pelt and as a con-sequence the population declined drastically in the1930s. The current population is estimated at60,000-70,000 individuals, with an annual allowedcommercial kill of 5,000-6,000 seals (Nowak 1991;Reijnders et al. 1993). The threats to, and pressureson, these seals are stemming mostly from pollutionfrom pulp and paper mills and from the mannerin which they are harvested. Many seals are shotbut left to die. Others, mostly pups, are affected bydisturbance from boats and gunners when onshore, causing high mortality rates. In 1981, forexample, close to 10,000 pups died because of dis-turbance. It is estimated that mortality from hunt-ing is 20-40% higher than the commercial records


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indicate and that the focus on hunting young sealsfor their pelt is causing a change in the populationstructure that may have consequences (Reijnderset al. 1993).

The Lake Ladoga seal is only found in this lakein the region of Karelia in Russia. The estimatedpopulation in 1992 was between 10,500 and 12,500individuals (Reijnders et al. 1993). The species isconsidered as vulnerable to extinction (IUCN2002). The species is legally protected and cannotbe harvested, although 200-300 individuals arecaught annually as bycatch in the local fisheries(Reijnders et al. 1993). The other subspecies of P.hispida is found exclusively in the Finish LakeSaimaa. This species is classified as endangered(IUCN 2002). The greatest threats are entangle-ment in fishing gear, pollution, and increasinglylakeshore development, boating, tourism and waterlevel control for a power plant. This last threatcauses the ice sheets to break, which during breed-ing season leads to many deaths of newborn pups.Even though the species has been protected since1955, and fisheries have been banned from mainbreeding areas, as of 1991, only 160-180 individu-als remain (Reijnders et al. 1993.)

Finally, there is a population or a subspecies(depending on the author consulted) of theCommon or Harbor seal that is found in freshwa-ter: the Phoca vitulina mellonae or Ungava seal(Reijnders et al. 1993). This seal is also known asSeal Lake seal and Lac des Loups Marins sealbecause of its distribution in several lakes in theCanadian province of Quebec. The species’ statushas not been assessed because of insufficient infor-mation. However, hydroelectric development in theNastapoca River will most likely cause a change inthe water level of the area lakes posing a threat tothe species.

3.11.8 Order Sirenia (manatees)

Sirenians are aquatic mammals that live in coastaland freshwater regions of the tropics. There are 4species of sirenians in the world, the dugong, a

marine mammal found in the Indian Ocean andthe South Pacific, and three species of manatees: 1in the coastal waters and some rivers of Central-West Africa, 1 in the Amazon basin and 1 in SouthAmerica and the shores of the Caribbean, includ-ing Florida (Nowak 1991). This latter species isknown as the West Indian manatee (Trichechusmanatus). It is vulnerable to extinction accordingto IUCN, and even rare or extinct throughoutmuch of its range (IUCN 2002). This is the onlysirenian species in North America, where it can befound along the Southeast coast of the U.S. up toNorth Carolina (Nowak 1991; Whitaker 1991). Itlives in coastal waters, bays, rivers and lakes. It ishunted in South and Central America for meat,while in the U.S. the biggest threat is accidentalkilling with boat propellers. Currently the U.S. gov-ernment is trying to restore the species in the US,where it performs an important ecosystem serviceby reducing the amount of water hyacinth thatchokes many waterways (Whitaker 1991).

Trichechus inunguis lives in areas with denseaquatic vegetation in the Amazon River and lowerreaches of its tributaries. This is the only manateethat lives exclusively in freshwater. It used to becommon but its populations have collapsed due tohunting for their meat and skin. The Amazonmanatee is vulnerable to extinction and legally pro-tected, but still continues to be hunted (Nowak1991; IUCN 2002).

The third manatee species is the West Africanmanatee (Trichechus senegalensis), which lives incoastal water and rivers from Senegal to Angolaand is also considered vulnerable to extinction(Nowak 1991; IUCN 2002).

3.11.9 Order Artiodactyla (even-toedungulates or hoofed mammals)

The most well known freshwater mammals in thisorder are the hippopotami, which only occur inAfrica. There are two living species, the commonhippopotamus (Hippopotamus amphibius) and thepygmy hippopotamus (Hexaprotodon liberiensis)


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(IUCN/SSC Hippo Specialist Subgroup 2003).Historically the range of the common hippopota-mus extended throughout Africa from the Niledelta all the way to the Cape, wherever there waspermanent water and grazing area (Nowak 1991).Currently its distribution is limited and in 1993 theestimated population in Africa was around 157,000,the largest population being in Zambia with 40,000individuals (IUCN/SSC Pigs and Peccaries SpecialistGroup, and the IUCN/SSC Hippo Specialist Group1993). The major threats to these animals are habi-tat loss from water reclamation and diversion foragricultural and large scale development projects,which are increasing in Africa with populationgrowth and competition for water resources, andillegal hunting for meat and ivory (Lewison pers.comm. 2002). Legal and illegal trade in hippo teeth(ivory) has increased in recent years. Illegal huntingfor meat has also occurred extensively in areas withcivil unrest (e.g., in Uganda and the DemocraticRepublic of Congo) (Kingdon 1997; Lewison pers.comm. 2002; IUCN 2002). The international tradeban on elephant ivory has encouraged the poach-ing and hunting of hippopotamus for their teeth,as an alternative. The annual export of hippo teethfor example, increased by 530% within two years ofthe ivory ban taking effect (IUCN/SSC HippoSpecialist Subgroup 2003). The last populationtrend estimates for this species published in 1993,showed that the species was declining in 18 coun-tries, was stable in 6 or 7, and increasing only in2: Congo and Zambia. For eight additional coun-tries the population trend in common hippos is notknown, and it is thought that it has disappearedfrom 2 countries: Liberia and Mauritania (IUCN/SSC Hippo Specialist Subgroup 2003). The hippois not listed as threatened by IUCN, however thesubspecies from Chad and Niger is listed as vulner-able (IUCN 2002).

The pygmy hippo inhabits forested waterways,and today is only found in isolated populations invery restricted locations near river deltas in coastalWest Africa (Kingdon 1997). IUCN lists the pygmyhippopotamus as vulnerable to extinction in Côte

d’Ivoire, Guinea, Liberia, and Sierra Leone. The sub-species found in Nigeria is considered criticallyendangered (IUCN 2002). Information on thisspecies, however, is limited. The SSC HippoSpecialist Subgroup estimates that “at best, 3000pygmy hippos may still remain” in the wild and thatonly “isolated populations may exist in the neigh-boring countries of Cote d’Ivoire and Sierra Leone,however these groups may be numbered in nomore than the dozens” (IUCN/SSC Hippo Spe-cialist Subgroup 2003). The major threats to pygmyhippos are deforestation and habitat fragmentation,pollution especially from oil, and hunting(IUCN/SSC Pigs and Peccaries Specialist Group,and the IUCN/SSC Hippo Specialist Group 1993).

Other freshwater-dependent ungulates notclassified strictly as freshwater mammals but thatspend considerable time foraging in or aroundfreshwater are also included in this section. Onesuch mammal is the moose or elk (Alces alces),which is distributed throughout Canada, Alaska,the Rocky Mountains, and into Maine andMinnesota in the United States, as well as inNorthern Europe, the Caucasus, and eastern Siberia(Whitaker 1991). This species is not endangered.

Similarly, in Asia there are two deer speciesthat spend considerable time foraging among reedsand rushes along rivers, and in and around swampsand marshes. These are the Chinese water deer(Hydropotes inermis), which inhabits the lowerreaches of the Yangtze basin, Korea, and has beenintroduced into France and the United Kingdom(Nowak 1991) and Père David’s deer (Elaphurusdavidianus), which originally was found in north-eastern and east-central China, but has disappearedfrom the wild. Today it is only found in zoologicalparks and reserves around the world, or in smallre-introduced populations. According to WWF andWCMC (1997) in 1992, a re-introduced herd inDaFeng Reserve, Jiangsu Province, numbered 122animals. This species is considered critically endan-gered (IUCN 2002). The Chinese water deer is clas-sified as lower risk, but close to becomingvulnerable (Wemmer 1998).


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Another water-dependent ungulate found inthe region is the Asian water buffalo (Bubalusbubalis). This species ranges from India and Nepalto Malaysia and Vietnam and lives in wet grass-lands, swamps and densely vegetated river valleys(Nowak 1991). The wild Asian water buffalo is con-sidered endangered with an estimated total popu-lation of less than 4,000 animals. Some estimatessuggest that this number is much lower, closer to200 animals, and that most are probably not pure-bred. However, IUCN points out the difficulty inassessing the status of this species because of theproblems distinguishing domesticated buffalos, feralbuffalos, hybrids and their wild relatives (IUCN2002). The major threats to the species are inter-breeding with domestic and/or feral buffalo, hunt-ing, and habitat loss.

There are also some semi-aquatic ungulates inAfrica. One example is the sitatunga (Tragelaphusspekei), which spends most of its time in grass bedswithin swamps. It is distributed from Gambia tosouthern Sudan, and south to northern Bostwana.The species is not endangered. There is also anAfrican water chevrotain, but information on thisspecies is very scarce (Wemmer 1998). The othergroup of ungulates that depends highly on waterresources are the 5 species from the genus Kobus.This group includes the waterbuck, two species oflechwes, the kob, and the puku. These animals usu-ally live in swamp areas, moist savannahs andfloodplains (Nowak 1991). All species are consid-ered at lower risk of extinction, except for two sub-species of lechwes that are listed as vulnerable, theKafue lechwe and the Black lechwe, both found inthe Kafue flats in Zambia (IUCN 2002).

In South America, from southern Brazil andPeru to northeast Argentina and Urugay, the Marshdeer (Blastocerus dichotomus) lives in marshes, wetsavannahs, and damp forest edges. It is consideredvulnerable to extinction mainly from habitat lossand competition from exotic species (Nowak 1991;Wemmer 1998; IUCN 2002).

3.11.10 Order Cetacea(freshwater dolphins)

River dolphins and porpoises are among the mostthreatened mammals in the world. There are 5species of river dolphins, and one of freshwaterporpoise living in large rivers in southern Asia andSouth America. Populations of river cetaceans havedeclined rapidly in recent years and much of theirhabitat has been degraded. The Asian species inparticular, are highly threatened. Threats to theseanimals include loss of habitat, siltation and pollu-tion of rivers, fragmentation of rivers by levees,dams and canals, depletion of their food sourcefrom overfishing by humans, accidental deathsfrom boat collisions, and entrapment with nets andother fishing gear. Four out of the 5 species ofAsian freshwater cetacean are either criticallyendangered or endangered according to IUCN’sRed List of Threatened Species. The fifth species,the Irrawaddy River dolphin, is listed as data defi-cient. The single South American freshwatercetacean species, the Amazon River dolphin, islisted as vulnerable (IUCN 2002).

There are 5 species of freshwater cetaceans inAsia: the Yangtze River dolphin, the Yangtze Riverfinless porpoise, the Indus River dolphin, the GangesRiver dolphin, and the Irrawaddy River dolphin.

The Yangtze River dolphin or baiji (Lipotesvexillifer) is the world’s most critically threatenedcetacean with only a few tens of individualsremaining. According to experts there is “little hopefor the survival of this species.” (Reeves et al. 2000).Prior to 1900 there were a few thousand dolphinsin the Yangtze basin (Ellis et al. 1993). The historicdistribution included lower and middle reaches ofthe Yangtze River as well as some tributaries andlakes in the basin. The Three Gorges marked theupper limit of the baiji’s distribution. By 1980 anestimated 400 individuals remained and by 1993only 150 remained with their range substantiallyreduced (Ellis et al.1993). Today, the few remain-ing individuals can be found just in the main-stream of the Yangtze River (Reeves et al. 2000).


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The main pressures on the baiji are the degrada-tion of its habitat mostly from pollution, waterdiversions, dams, overfishing of their prey, andfrom accidental deaths due to ship collisions, blast-ing and entrapment in fishing gear. The ThreeGorges Dam has exacerbated the pressures on theremaining population of dolphins.

Another cetacean found in the Yangtze, thefinless porpoise (Neophocaena phocaenoides) is theworld’s only freshwater-adapted porpoise, and itspopulation is reported to be declining rapidly.These animals are also classified as endangered(IUCN 2002). The most recent population estimategives an average of 2,700 individuals for the period1978-1991. Additional surveys carried out in 1991-1996 at separate locations throughout its rangeshow a sharp decline in population numbers, buta total population estimate was not provided(Reeves et al. 2000).

The other 3 freshwater cetacean species in Asiaare the Indus River dolphin (Platanista minor), theGanges River dolphin (Platanista gangetica), twospecies that are closely related, and the IrrawaddyRiver dolphin (Orcaella brevirostris). The IndusRiver dolphin or bhulan is found in the Indusbasin from the Himalayan foothills to the estuar-ine portion of the river leading into the ArabianSea. Originally, this species was abundant andcould be found throughout the tributaries of theIndus River in Pakistan and India. Today, the rangeand population numbers are in decline, and mostof the remaining population, estimated at less than1,000 individuals, is concentrated in the IndusRiver Dolphin Reserve, which was established bythe Sind provincial government in 1974. Thisreserve is located between the Sukkur and Guddubarrage (Reeves and Chaudhry 1998). The majorcause for the decline of the Indus dolphin was theextensive dam and barrage construction in the1930s, which altered migration patterns, isolatedpopulations and changed the flow and sedimentregime of the river. Today, accidental entrapmentin fishing gear, hunting for meat, oil and traditionalmedicine, and pollution is also impacting on the

species (Reeves et al., 2000). IUCN has classifiedthe species as endangered (IUCN 2002).

The Ganges River dolphin or susu is found inthe slowly flowing waters of the Ganges,Brahmaputra, Meghna and Karnaphuli-Sangurivers, from the foot of the Himalayas downstreamto the upper limits of the tidal zone, in Bang-ladesh, Bhutan, India and Nepal (Sinha et al.2000). This area also coincides with one of themost densely populated and food-poor areas ofthe world. Historically this species was quite abun-dant and found in large groups throughout itsrange. Close to 5,000 individuals were estimatedto live in the Indus river system (WWF India2002). Populations have severely declined sincehistorical times, with an estimated 1,200-1,500remaining today and an annual mortality rate of10% (WWF India 2002). This species is classifiedas endangered (IUCN 2000, Reeves et al. 2000).Like the baiji, the major threats to the Ganges dol-phin is the high level of river fragmentation dueto dams, canals, etc., accidental killings from shipsand fishing gear, direct harvest for oil and tradi-tional medicines, pollution, and overfishing of itsfood source (Sinha et al. 2000).

The status and biology of the Irrawaddy dol-phin is not well known. The species is foundmainly in the Irrawaddy (Myanmar), the Mekong(Vietnam, Cambodia, and Laos) and the Mahakam(Kalimantan, Indonesia) river basins. This specieswas assessed by IUCN in 1996 and classified as datadeficient. The Mahakam subpopulation of thisspecies was assessed by IUCN in the year 2000, andclassified as critically endangered. Only 33-50 indi-viduals are estimated to be left in the middlereaches of the main river (Kreb 2000 as cited inIUCN 2002). The major causes of death of theMahakan subpopulation dolphins are collisionswith vessels, deliberate killings and live-capture forocean aquaria, bycatch and deaths because of otherfishing practices in the region (e.g., gillnets, elec-tricity and poison), and the accidental introductionof an exotic piscivorous fish that has contributedto deplete the dolphins’ prey. In addition, siltation,


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pollution and dams also contribute to the declineof this species (Krebs 2000 as cited in IUCN 2002).

River dolphins also occur in South Americabut are not considered as endangered as their Asianrelatives. The Amazon River dolphin (Inia geoffren-sis) is the largest of the river dolphins. The knownpopulations are distributed in the Orinoco basin,the Amazon basin, and in the Beni basin in Bolivia(IWC 2000). Threats include interactions with fish-eries, hydroelectric development, deforestation, andpollution from agriculture, industry and mining.Hydroelectric development poses the biggest threat.The current status of the Amazon River dolphin isvulnerable according to IUCN. Because of habitatdegradation and the current levels of exploitationin the region, there has been an estimated popula-tion decline of at least 20% over the last ten years(IUCN 2002). The other dolphin species in LatinAmerica is the Tucuxi or gray dolphin (Sotalia flu-viatilis). It is found in both fresh and saltwater,mostly in the Amazon basin and in the coastalwaters from the Amazon delta to Panama.


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Conservation organizations, international environ-mental agencies and many national governmentshave identified or designated habitats and eco-systems as conservation priority areas. These pri-ority setting exercises are based on a number ofdifferent approaches, but many times they aredriven by high species richness and endemism, orthe uniqueness of the landscape or habitat.Sometimes the focus is a particular group ofspecies, other times the conservation prioritymethodology is adapted to multiple taxa.

Much of the prioritizing work for conservationpurposes done to date has focused on terrestrialecosystems and species; one well-known exampleare Conservation International’s hot spots, which aremostly based on centres of high plant diversity andhighlight many tropical regions of the world asbeing of high conservation concern. Methodologiesto set conservation priorities for freshwater eco-systems have been lagging behind, but recently theytoo have become more prevalent, with some inter-nationally recognized conservation organizations,such as WWF-US and The Nature Conservancy,taking the lead at global, regional, subregional andeven local levels. Because of the increasing concernabout the conservation status and the high extinc-tion rates of many inland water species, more andmore conservation groups are beginning to look atinland waters as key ecosystems for conservation. Tofurther the work in this area, IUCN held a workshopin Gland, Switzerland, in June 2002 to develop a siteprioritization methodology for inland water eco-systems. The workshop brought together 24 partic-ipants from a range of organizations experienced inthe field of site prioritization schemes, freshwatertaxa, environmental impact assessments and othertechnologies. The objective of IUCN’s workshop wasto develop a methodology, building on existingapproaches, which will enable any party working onthe management, development or conservation ofinland waters to identify important areas for conser-vation of freshwater biodiversity. Specific qualifiersof the methodology were that it should be (a) simpleto use, (b) transparent in its rationale, (c) meet the

needs of a diverse range of potential end users, and(d) have the flexibility to operate on different geo-graphic scales. A summary of the conclusions andoutcomes of this workshop is given below.

4.1 SUMMARY OF THE IUCN METHODFOR PRIORITIZING IMPORTANT AREAS

FOR FRESHWATER BIODIVERSITY

As a result of the workshop held by IUCN, apriorization methodology was outlined, which willbe refined and adjusted over time, based on field-testing excercises. The methodology developed andpresented here is primarily driven by species-basedinformation, since this is the major strength ofIUCN’s Species Programme and its associatedSpecies Survival Commission network of experts.The IUCN Species Programme initially intends toemploy the tool to help develop the biodiversitycomponent of a number of regional wetlandsprojects being co-ordinated through the IUCNWater and Nature Initiative (WANI) and the IUCNregional offices. The tool is also intended to make acontribution to the programme of work of theConvention on Biological Diversity (CBD) oninland water biological diversity and to the jointworkplan between CBD and the Ramsar Con-vention. Hopefully, it will also help Parties to theConvention on Wetlands to identify new sites ofinternational importance.

The following steps outline the prioritizingprocess.Step 1: Define the geographic boundaries within

which to identify important areas or sites.Step 2: Define the wider ecological context of the

designated assessment area.Step 3: Identify and map the distribution of inland

water habitat types.Step 4: Assemble an inventory of the distribution

and conservation status of priority aquatic taxa.Step 5: Apply species based site selection criteria.Step 6: Ensure full representation of inland water

habitats among those sites selected.Step 7: Ensure inclusion of keystone species.


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4. INLAND WATER ECOSYSTEMS AND HABITATS IDENTIFIEDAS HIGH CONSERVATION PRIORITY


The selection criteria applied in Step 5 arebased on threatened species, restricted rangespecies, richness of biogeographically restrictedspecies, importance to critical life history stages,and significant numbers of congregatory species.

Guidelines for application of the criteria, anddefinitions of taxon-specific thresholds will be devel-oped and elaborated through an ongoing process ofconsultation with workshop participants and fieldtrials with regional users. Once the modificationshave been agreed upon, training on its use will beprovided through a series of regional workshops.

4.2 HABITATS IDENTIFIED ASHIGH CONSERVATION PRIORITY

FOR BIRDS

BirdLife International has identified 218 EndemicBird Areas (EBAs) worldwide—areas which encom-pass overlapping breeding ranges of restricted-rangebird species—some of which include wetlands as akey habitat component (Stattersfield et al. 1998).Because most restricted-range birds occur in forests,the number of EBAs with wetland ecosystems islimited: 5 in North and Central America, 5 in SouthAmerica, 4 in Africa and the Middle East, 1 in SouthAsia, 2 in Indonesia and Papua New Guinea, and4 in the South Pacific Islands. BirdLife has also iden-tified, or is in the process of identifying, anothercategory of priority areas for bird conservation:Important Bird Areas (IBAs). Whereas EBAs tendto be broadly defined regions across the globe, IBAsare particular sites of international significance forthe conservation of birds at the global, continentaland sub-continental level. So far, 5,647 IBAs havebeen identified across Africa, Europe and theMiddle East, of which 1,239 (22%) are inland wet-lands of global significance for the conservation ofwetland-dependent bird species (BirdLife Inter-national World Bird Database, as of June 2002).Identification of IBAs elsewhere in the world is welladvanced, and completion of the global IBA inven-tory, which will comprise up to 12,000 sites, isscheduled for 2005.

4.3 HABITATS IDENTIFIED ASHIGH CONSERVATION PRIORITY

FOR MULTIPLE TAXA

4.3.1 Priority Setting Exercises by NGOsfor Freshwater Habitats

The WWF-U.S. identified 53 areas of global impor-tance for freshwater biodiversity in 1998, as part ofthe Global 200 inititative—WWF’s conservationpriority areas—based on species richness, speciesendemism, unique higher taxa, unusual ecologicalor evolutionary phenomena, and global rarity ofmajor habitat types (Olson and Dinerstein 1998).WWF-US is currently conducting an assessmentfor Africa of “Freshwater Ecoregions” in terms oftheir biological distinctiveness and the level ofthreats with more detailed data on fish, mussel,crayfish, and herpetofauna. The study for Northand Latin America has been completed and pub-lished (Abell et al. 2000; Olson et al. 1998).

A 1998 study by WCMC entitled FreshwaterBiodiversity: a preliminary global assessment sum-marized existing information on the diversity offreshwater taxa, including freshwater fish, molluscs,crayfish, crabs, and fairy shrimp. “Important areasfor freshwater biodiversity” were identified basedon existing information and expert consultation onoverall diversity of an area to each of these taxa. Ofthe total 136 important freshwater biodiversityareas identified, 23 contain overlapping diversity ofmore than one of the assessed taxa (Groombridgeand Jenkins 1998). Table 12 summarizes WWF’sand UNEP-WCMC’s important areas for freshwa-ter biodiversity.

4.3.2 Internationally RecognizedProtected Areas

As of June 2003, 1,288 wetlands have been desig-nated as Ramsar sites—wetlands of internationalimportance under the Convention on Wetlands.The cumulative number of Ramsar sites has dou-bled in the last decade, although many of these sites


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are of relatively small size and located in developedcountries. Wetlands International maintains theRamsar database, which includes for each site, gen-eral location information (with geographic coor-dinates), site designation criteria, and the wetlandhabitat type represented. The Strategic Frameworkand the guidelines for future development of the

List of Wetlands of International Importance wereadopted at the 7th Conference of the Parties in1999. The framework and guidelines specificallycategorize the site designation criteria into 8 typesincluding the importance for fish and bird diver-sity. A brief summary of the criteria is listed inTable 13.


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Table 12. Areas of High Freshwater Biodiversity

WCMC Hotspots WCMC Important WWF Global 200 (areas important for areas for at least one

Freshwater Ecoregions more than one taxa) of the 5 taxa assessed

Africa 9 7 32

Eurasia 13 9 45

Australasia 15 2 14

North America 7 3 18

South America 9 2 27

Sources: Olson and Dinerstein 1999; summarized from Groombridge and Jenkins 1998.

Table 13. Summary of Criteria for Identifying Wetlands of International Importance

Group A Criteria • Sites containing representative, rare or unique wetland types

Criterion 1: A wetland should be considered internationally important if it contains a representative, rare,or unique example of a natural or near-natural wetland type found within the appropriate bio-geographic region.

Group B Criteria • Sites of international importance for conserving biological diversity

Criterion 2: A wetland should be considered internationally important if it supports vulnerable, endangered,or critically endangered species or threatened ecological communities.

Criterion 3: A wetland should be considered internationally important if it supports populations of plantand/or animal species important for maintaining the biological diversity of a particular bio-geographic region.

Criterion 4: A wetland should be considered internationally important if it supports plant and/or animalspecies at a critical stage in their life cycles, or provides refuge during adverse conditions.

Criterion 5: A wetland should be considered internationally important if it regularly supports 20,000 or morewaterbirds.

Criterion 6: A wetland should be considered internationally important if it regularly supports 1% of theindividuals in a population of one species or subspecies of waterbird.

Criterion 7: A wetland should be considered internationally important if it supports a significant proportionof indigenous fish subspecies, species or families, life-history stages, species interactions and/orpopulations that are representative of wetland benefits and/or values and thereby contributes toglobal biological diversity.

Criterion 8: A wetland should be considered internationally important if it is an important source of food forfishes, spawning ground, nursery and/or migration path on which fish stocks, either within thewetland or elsewhere, depend.

Source: Ramsar Convention Web site at: http://www.ramsar.org/key_criteria.htm


In many instances, wetland areas have alsobeen selected for protection as part of the WorldHeritage Convention and the Man and the Biosphere

Programme of the United Nations EducationalScientific and Cultural Organisation (UNESCO).There are 149 World Heritage sites designated on


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Table 14. Number of Ramsar Sites and Habitat Representation

Ramsar Region Total Marine/Coastal Inland Manmade Unclassified

Africa 113 49 95 26 2

Asia 153 62 103 41 7

Europe1 778 348 641 260 11

North America 62 33 53 13 0

Neotropics 111 56 87 19 4

Oceania 71 38 57 7 0

Grand total 1288 586 1036 366 24

1 Europe includes overseas territories and dependencies. Note: Many sites have a combination of coastal, inland, and manmadewetlands represented and counted as such. Therefore the figures for the 4 categories do not add up to the figures in the total.

Source: Ramsar Sites Database, June 2003.

Table 15. Number of Ramsar Sites and Primary Wetland Types1

Wetland type(s) Primary wetland type

Estuarine waters (F) 82

Intertidal mud, sand, or salt flats (G), and/or Intertidal marshes (H) 156

Intertidal forested wetlands (I) 48

Coastal brackish/saline lagoons (J) 114

Coastal freshwater lagoons (K) 17

Inland deltas (L) 23

Permanent and/or seasonal rivers/streams/creeks (M and/or N) 82

Permanent and/or seasonal freshwater lakes (O and/or P) 273

Permanent and/or seasonal saline/brackish/alkaline lakes and flats (Q and/or R) 80

Permanent and/or seasonal saline/brackish/alkaline marshes/pools (Sp and/or Ss) 32

Permanent and/or seasonal freshwater marshes/pools (Tp and/or Ts) 148

Peatlands, non-forested and/or forested (U and/or Xp) 151

Alpine wetlands (Va) 1

Tundra wetlands (Vt) 16

Shrub-dominated wetlands (W) 16

Freshwater, tree-dominated wetlands (Xf) 53

Freshwater springs; oases (Y) 2

Geothermal wetlands (Zg) 1

Subterranean karst and cave hydrological systems (Zk) 4

Source: Ramsar Sites Database, July 2003

1 Many sites have several wetland types listed as the primary wetland type and that therefore the total is not equal to the totalnumber of Ramsar sites (1291 sites)


the basis of natural properties or mixed natural-cultural properties and 440 Man and the Biospherereserves. Some internationally protected areassimultaneously encompass areas protected underother systems. For example, as of November 2002there were 72 biosphere reserves that are wholly orpartially World Heritage sites; 24 sites are inscribedas both Ramsar and the World Heritage sites.

In addition, IUCN, in collaboration withUNEP-WCMC, assessed those World Heritage sitesthat had a wetland component (Thorsell et al.1997). According to this study, among the 721World Heritage sites worldwide existing at the time,77 contained major or secondary wetland habitats.These 77 sites represented 50 countries and rangedin size from 19 hectares, Aldabra Atoll in theSeychelles, to a 140,000-hectare Sundarbans man-grove forest in Bangladesh and the 3.15 millionhectare Lake Baikal in Russia (UNESCO 2003).


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86


The indicators and information presented in theprevious sections show that human activities haveseverely affected the condition of inland waterecosystems all over the world. Habitat degradation,invasive species, overexploitation, and pollution,are all stressing the capacity of inland water eco-systems to support biodiversity, with many speciesfacing rapid population declines or extinction.Critical freshwater habitats, such as wetlands, riversand streams, are also getting increased pressuresand demands on their use, causing the disappear-ance of some of the remaining refuges for manyspecies as well as areas for food production andwater availability for local communities, particu-larly the poor.

Although physical alteration to inland water-ways have increased the amount of water availablefor human use, for example through reservoirs, ithas been estimated that today more than 2 billionpeople are affected by water shortages over40 countries (WWDR 2003). In addition, surfaceand groundwater is being degraded in almostall regions of the world by intensive agricultureand rapid urbanization, aggravating the waterscarcity problem.

Although many of the options available toimprove water resources management to benefitboth people and nature fall within the economicand political realm, ongoing monitoring andassessment of inland water ecosystems is crucialto informing and guiding policy or economicaction. Governments, international agencies,NGOs, river basin authorities, and civil societyneed data and information on the condition ofinland water resources, their ecosystem functions,their dependent species and the livelihoods ofpeople dependent upon them, in order to formu-late and implement policy options that are sus-tainable. For example, better information onactual stream and river discharge, and the amountof water withdrawn and consumed in each basin,would increase our ability to manage freshwatersystems more efficiently and evaluate trade-offs.However, information and data on freshwater

resources at the global level are scarce. To fill inthe gaps, much effort and financial commitmentwould have to be made. However, the rewards fordoing so are significant.

In general, all areas related to inland waterecosystems require more data and information,from water availability and quality to the status andpopulation trends of freshwater species. Becauseadopting such an information gathering effort atthe global level would be a daunting task, we haveselected areas where an incremental amount ofeffort would produce fruitful results. These sug-gested areas build on ongoing or planned assess-ments and information gathering activities.

5.1 HABITAT INVENTORYAND INDICATORS OF CONDITION

AND CHANGE

Among the different datasets on land cover, thereis currently a lack of biogeographic characteriza-tion and standard classification schemes, especiallyas it relates to wetland ecosystems. Remote sensingtechnology, for example, has not been very success-ful in mapping wetlands. Part of the problem isthe coarse resolution of most satellite imagery,although this is improving every year. The othermore problematic area is the difficulty in mappingseasonal wetlands and forested wetlands. Radar,which can sense flooding underneath vegetationand can penetrate cloud cover, is probably the bestalternative for developing a global wetland data-base. Because of its high resolution and sensitivityto water, radar data reveal a much finer wetlandtexture, particularly in areas of flooded forests, thanother remotely sensed data. However work in thisarea is minimal with most remote sensing groupsfocusing on terrestrial habitats. The EuropeanSpace Agency has initiated a programme to assessthe application of earth observation products interalia for managing wetlands, especially those desig-nated under the Ramsar Convention. Results fromthis programme can prove useful to the widerwater resources community.


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5. DATA GAPS AND INFORMATION NEEDS


There is also hope that the launch of Landsat 7in 1999, which includes a 15-meter resolutionpanchromatic band sensor, in addition to five 30-meter resolution optical and infrared bands, can beused to resolve more detailed land-cover features. Inan attempt to maximize use of these data, the priceper image has also been reduced from US$4,200 toUS$600. Higher quality data, available on a regularbasis and at modest cost, should allow more accu-rate mapping of the general extent of large perma-nent wetlands. However, to map other smaller,seasonal, and forested wetlands, a resolution of lessthan 15 meters may be needed (USGS Landsat 7Web site available at: http://landsat7.usgs.gov/).

5.2 SPECIES INFORMATION

In general, information on biodiversity at thespecies level in most freshwaters is poor. Somegroups, for example birds, are better covered butfor most others the cover is poor. Even economi-cally important groups such as fish tend to bepoorly covered at the global scale although somecountries have better inventories. Information onfreshwater biodiversity is often not readily available.For example, in most countries’ reports, MSc andPhD theses are produced in the national languageand may be hidden in archives. The usual languagebarriers to information access and disseminationare also evident. In addition, the existing speciesinventories are organized by taxonomic group andnot by ecosystem type, which makes it hard toassess the condition of inland water ecosystems.Freshwater species have traditionally been neg-lected, and because of their distribution withinwater bodies they are more difficult to map thanterrestrial species. The above mentioned problemsmake it very difficult to assess threats to species,and therefore the overall condition of ecosystems.Currently the trend is shifting from single-speciesoriented conservation to ecosystem or habitat-levelconservation and activities.

Because monitoring and assessing all freshwa-ter species is a daunting task, countries and institu-

tions are encouraged to monitor key indicatorspecies for freshwater systems, as well as monitor-ing the presence or introduction of exotic speciesand their impacts on native fauna and flora. Thereare several new initiatives that may help identify,catalogue, and map species around the world. Someof these activities include IUCN’s freshwater biodi-versity assessment and Species Information Service,the work of BirdLife international on the location,distribution and population status of birds, theOECD’s Global Biodiversity Information Facility(GBIF) and the Global Taxonomy Initiative of theConvention on Biological Diversity. This knowledgeand monitoring would allow for a more completeassessment of the condition of freshwater systems.

There is also great potential to improve theavailable information on species distribution andrichness by drawing from the existing museum col-lections and databases around the world. Thesedatabases contain detailed information that wouldallow the mapping of species distribution range,the identification of areas of high diversity, as wellas the existing data gaps. Overall, museum collec-tions in Europe, North America, Australia, andJapan contain many specimens and informationfrom poorly sampled areas in the tropics.Mobilizing the data and integrating them into asatandard format could help fill many of the exist-ing gaps. In general, accessibility to museum col-lections depends on the particular institution, whilethe usability of the data and information dependson the species group and the level of taxonomicknowledge on the groups. An effort to mainstreamthe use of these vast amounts of information, how-ever, is encouraged.

Another important monitoring area that ismissing not only for freshwater, but for most ter-restrial and marine species, is trends in species’populations. Here only quantitative data may be ofvalue. The existing data are patchy even for a sim-ple assessment of the current status of a species.There are very few cases where baseline data infor-mation on abundance and distribution of a speciesis available. However, without population trends of


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species, it is hard to assess the effects of pressuresor the risk of extinction of species.

Finally, because of the large impact that intro-duced species can have on inland water ecosystems,information on the location of introduced speciesas well as the presence or absence of invasive speciesis urgently needed. Regarding information on fishintroductions, the FAO DIAS compiles and main-tains information on the degree of internationalintroductions by country, which, as of 1998, con-tains 3,150 records worldwide. The largest percent-age of these introductions (35.5%) took placebetween 1940 and 1979 (FAO 1998). It should benoted however, that the DIAS database considersonly species introduced from one country toanother and not within-country introductions ortranslocations. Another example of a global initia-tive that tries to document the occurrence of inva-sive species is Global Invasive Species Database,being developed and maintained by the IUCN/SSCInvasive Species Specialist Group (ISSG) and GlobalInvasive Species Programme (GISP). This databasecurrently list only 3 well-known invasives by thehabitat category “water”: Zebra mussel (Dreissenapolymorpha), Water hyacinth (Eichhornia crassipes),and Chinese mitten crab (Eriocheir sinensis).

Regional or national monitoring programmesoften have more detailed information specific tothe region. For example, the Group on AquaticAlien Species (GAAS) in Russia has compiled doc-umentation on 6 aquatic invasive invertebratesfound in enclosed seas of Europe and the GreatLakes region of North America, including amapped range of original and current occurrence(GAAS 2002). Detailed information and distribu-tion maps of a number of nonindigenous aquaticspecies including vertebrates, invertebrates, andplants, are also available for the U.S. (USGS 2001).

5.3 WATER RESOURCE INFORMATION

Although water is essential for human survival,information of this resource is lacking in manyparts of the world. Most data on water availability

and use are only available at the national level,which makes management of river basins, especiallythose that cross national borders, almost impossi-ble. Data and information on basic variables, suchas river flow, water withdrawals, aquifer rechargerates, etc. are not often available at the basin level.Most of the current data available are based onmodels developed from climate and precipitationdata, and then validated with some observed data.

If information on water availability and use islacking, the amount of information on water qual-ity is even more depressing. Better information onwater quality can provide nations with immediatebenefits because of the direct connection betweenwater quality and human health. But gathering suchinformation generally requires expensive monitor-ing networks that are beyond the reach of manydeveloping countries. Even though surface watermonitoring programmes are well developed inmost countries of the Organization for EconomicCooperation and Development (OECD), waterquality monitoring in most parts of the world isrudimentary or nonexistent. Even those developedcountries that have water quality monitoring pro-grammes in place focus on chemical parametersthat leave out important biological information.One of the biggest challenges in future water mon-itoring programmes is the integration of chemicaland biological measures of water quality. Nationalgovernments are encouraged to establish waterquality monitoring programmes that combinechemical and biological measures for both surfaceand groundwater.

If surface water monitoring is lacking in manycountries, the situation for groundwater is evenworse. Most nations lack groundwater monitoring,both in terms of its quantity and quality.Information on groundwater quality, as well as onstorage capacity and use, is urgently needed.Currently there are two proposed initiatives thatcould help fill in the information gap on ground-water resources as well as promote their soundmanagement. One of these initiatives is theGroundwater Management Advisory Team, coor-


89


dinated by the World Bank and the Global WaterPartnership. The aim of this team is to promoteincreased knowledge and efficient management ofgroundwater resources around the world. The sec-ond proposed initiative is to create an InternationalGroundwater Resources Assessment Center, whichwill collect data on and monitor groundwaterresources worldwide. This initiative is being under-taken by UNESCO and WMO.

5.4 SOCIO-ECONOMIC DATA

In addition to ecosystem-specific datasets, greatlyimproved socio-economic information at alllevels is essential for a more integrated approachto water resource management. Some socio-eco-nomic variables needed at the basin level include:population density and distribution in relation towater resources; income distribution; the degreeof dependence on inland waters and the biodiver-sity they support; food production from inlandwaters, etc.


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Annex I. REVIEW OF SOME ONGOING ASSESSMENTS AND INITIATIVES ONWATER RESOURCES AND INLAND WATER BIODIVERSITY

There are a number of freshwater assessments andinitiatives going on around the world. The majorityof these initiatives focus on broad freshwaterresources issues, such as sustainable management ofwater resources; water for agriculture vs. nature; andthe assessment of freshwater resources at the basinand global levels. Less numerous are those initiativesor assessments focusing on inland water species andconservation. This section provides a short sum-mary of the different activities and the main insti-tutions and organizations involved, starting withthose more directly linked to biodiversity, and mov-ing on to the broader water-related activities.

1. IUCN’S FRESHWATERBIODIVERSITY ASSESSMENT

IUCN launched the Water and Nature Initiative(WANI) in 2001. WANI is a collaborative effort ofover 50 organizations worldwide to address thewater crisis. The Initiative builds on the IUCNWater and Nature Vision and Framework forAction (March 2000), and responds to the call foraction voiced at the 2nd World Water Forum inThe Hague in March 2000, which identified thelack of freshwater biodiversity-related informationas a key obstacle in the development of integratedwater resource management.

The goal of the IUCN Water and NatureInitiative is the mainstreaming of an ecosystemapproach into river basin policies, planning andmanagement. This is needed to build a world inwhich the benefits of freshwater and relatedecosystems to humankind are optimized, whilethe intrinsic values of these systems are respectedand preserved.

As part of this initiative, IUCN’s SpeciesSurvival Commission and the Ramsar Bureau haveembarked on a project entitled Benchmarking fresh-water biodiversity for better design of sustainablewater management strategies. The aim of this proj-ect is to gather and synthesize data on the status offreshwater biodiversity and build the needed capac-ity to incorporate freshwater biodiversity in water

resources planning and management. One of theexpected outcomes will be to highlight priorityconservation areas for freshwater species, whichcontrasts significantly with those richest in terres-trial biodiversity. The information generated willsupport the implementation of the RamsarConvention on Wetlands and the CBD, especiallyat the national level (WANI Web site at:http://www.waterandnature.org).

In addition, the IUCN/SSC has a broaderFreshwater Initiative, which will compile informa-tion on key freshwater taxonomic groups, whichserve as indicators of freshwater biodiversity andecosystem integrity; enhance the SSC’s expertisenetworks on these species; assist in the identifica-tion of critical sites for freshwater biodiversityconservation; identify and address processes threat-ening freshwater biodiversity, and communicate theresults to a broader audience.

Both efforts aim to address the gaps and lackof global coverage in current information on fresh-water ecosystems, and calls for the generation ofknowledge and the translation of existing informa-tion into formats that are accessible to water pol-icy makers and water managers.

The first area of activity will be clarifying thedegree of threat to freshwater biodiversity by car-rying out a Red List assessment of freshwaterfishes, amphibians, and key plant and invertebrategroups. The networks developed to assess the sta-tus of the indicator species’ groups will also iden-tify the critical geographic sites and the majorthreats to these species.

2. IUCN/SPECIES SURVIVALCOMMISSION SPECIES

INFORMATION SERVICE

The IUCN/SSC has initiated a project to gather,compile, and map baseline species data: theSpecies Information Service (SIS). Data and infor-mation compiled will include: species distributionmaps; population trends; species’ ecologicalrequirements (e.g., habitat preferences, altitudinal


ranges); degree and types of threat (conservationstatus according to IUCN Red List Categories andCriteria); conservation actions (taken and pro-posed); and key information on use of each par-ticular species. In addition, the SIS hopes toprovide species biodiversity analyses that draw onthe baseline information. One of the first productsthat the SIS is working on is the mapping of allmammal species and the Global AmphibianAssessment, which is incorporating the informa-tion on all 5,000 species of amphibians into theSIS. All the ranges for African mammals have beenmapped and their status assessed. The amphibianmapping work is expected to be completed byearly 2004. Work on other groups such as reptiles,freshwater fish, marine fish, molluscs, plants,butterflies and other selected invertebrate groupswill continue throughout 2003 (IUCN/SSC Website at http://www.iucn.org/themes/ssc/). Finally,the key conservation-related information on allglobally threatened birds has been mapped andsummarized by BirdLife International, in collabo-ration with numerous experts, national Partnersand the IUCN Species Survival Commission(BirdLife International 2000).

3. WWF-US FRESHWATERECOREGIONAL ASSESSMENTS

Within its Ecoregions of the World project, whichaims to assess and map the conservation statusof terrestrial, freshwater and marine ecorgions,WWF-US has an ongoing freshwater ecoregionanalysis. The terrestrial realms include NorthAmerica, Indo-Pacific, Africa, Eurasia, LatinAmerica and the Caribbean, and Oceania. The goalof the freshwater ecoregional analysis is to delineatefreshwater conservation units based on zoogeogra-phy, and synthesize biodiversity information for allunits. The goal of the project is to improve conser-vation initiatives at the international, regional, andlandscape levels. WWF defines ecoregions as “rela-tively large units of land or water containing a dis-tinct assemblage of natural communities and

species, with boundaries that approximate the orig-inal extent of natural communities prior to majorland-use change.”

The global work builds on several moredetailed continental scale assessments. Assessmentsfor Latin America and the Caribbean and NorthAmerica have been published, and a volume forAfrica is underway. These assessments include eval-uations of both biodiversity and threats. Bio-diversity visions describing what will be requiredto maintain biodiversity targets of ecoregions in thelong term, are also being developed for WWF’s pri-ority ecoregions. Ecoregions with a freshwaterfocus include the southeast rivers and streams inthe U.S., the Amazon River and flooded forests, theCongo River basin, lower Mekong River basin, andNiger River basin (WWF US Web site at:http://www.worldwildlife.org/ecoregions/related_projects. htm.).

4. WWF WATER AND WETLANDINDEX FOR EUROPE

WWF’s Water and Wetland Index provides a “snap-shot” of the condition of key freshwater ecosystemsin Europe and can be used as a tool to set priori-ties for action. It also serves as a measure of thepreparedness of governments to effectively managetheir water resources, using the EU WaterFramework Directive as a guide.

The index takes into consideration the mainpressures on freshwater ecosystems (e.g. agriculture,aquaculture, industrial pollution, etc.), the ecolog-ical quality of its habitats, the status and loss of bio-diversity, the status and use of water resources, andthe quality of monitoring programmes.

The first phase of the Water and WetlandIndex (WWI-1) ran from August 1999 to June2001 and aimed at providing a ‘snapshot’ of thefreshwater status in 16 European countries(Austria, Belgium, Bulgaria, Denmark, Estonia,Finland, France, Germany, Greece, Hungary,Slovakia, Spain, Sweden, Switzerland, Turkey andthe United Kingdom). The WWI-1 produced and


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scored 49 indicators assessing: a) the “ecologicalstatus” of rivers, lakes, mires and wetlands; b) thecondition of threatened freshwater species; c) pres-sures and impacts on freshwater; and d) the qualityof the monitoring programmes. Data collection,scoring of indicators and index development wasdone in close collaboration with WWF offices andpartner NGOs in the respective countries.

The results of the first phase, point to 3 keyfindings:1. Fifty out of 69 river stretches in Europe were

found to be of poor ecological quality due tothe impacts of canalisation, dams, pollutionand altered flow regimes;

2. Governments are in a weak position to protectbiodiversity in freshwater ecosystems withinEurope’s “nature network”;

3. Most European countries have inadequateenvironmental monitoring systems to prop-erly safeguard their water resources.

The second Phase of the Water and Wetland Indexis aimed at the evaluation of Government’s waterpolicy, especially in relation to the implementationof the EU Water Framework Directive, the appli-cation of Integrated River Basins Management(IRBM) principles and the quality of the pro-grammes that are being implemented to solve themost urgent freshwater problems in each country.The second phase is currently under development(March 2002-October 2003) and includes 3 subsetsof indicators:1. Use of international legal instruments;2. Application of IRBM principles;3. Response to pressures and impacts that will be scored both in EU and non-EUcountries.

5. DECLINING AMPHIBIANPOPULATIONS TASK FORCE (DAPTF)

IUCN/SSC established the DAPTF in 1991 as aresponse to the alarming decline in amphibian pop-ulations around the world. The DAPTF operatesthrough a network of 90 Regional Working Groups

formed by experts and volunteers that collectgeographical data on amphibian declines and theircauses. DAPTF also provides funds to specificresearch projects related to amphibian declines.Currently DAPTF is focusing on producing a reviewof the amphibian population decline, developingand compiling information for the amphibian data-base that will provide researchers with all availabledata on the status of amphibian populations world-wide, and a compendium of reports from theregional working groups, which will bring informa-tion on the status of amphibian populations, partic-ular threats to amphibians, and any recordeddeclines in their region into the public domain(DAPTF Web site at: http://www.open.ac.uk/daptf/index.htm.)

6. BIRDLIFE INTERNATIONAL’SIMPORTANT BIRD AREAS

BirdLife International has identified, and is in theprocess of identifying, priority areas for bird con-servation: Important Bird Areas (IBAs). IBAs aresites of international significance for the conserva-tion of birds at the global, regional or sub-regionallevel. They are identified using standardized, inter-nationally agreed criteria and are intended to be apractical tool for conservation. The IBAs encom-pass a range of habitat types, including inland andcoastal wetlands that support a variety of water-birds. A regional inventory of IBAs in the MiddleEast was published in 1994, covering 391 siteswithin 14 countries/territories (Evans 1994). Arevised pan-European IBA inventory was publishedin 2000, covering 3,619 sites in 51 countries/terri-tories (Heath and Evans 2000). In 2001, the firstpan-African inventory was published, covering1,230 sites in 58 countries/territories (Fishpool andEvans 2001). Regional assessments are nearing com-pletion in Asia and Antarctica, and are ongoing inthe Americas and Pacific regions (BirdLifeInternational 2001). It is anticipated that up to12,000 IBAs will have been identified when globalcoverage is completed by 2005.


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In addition to the regional IBA publications,at least 40 national IBA inventories have alreadybeen prepared and published in the national lan-guage by BirdLife Partner organizations. Theseinclude 11 from Africa, 3 from Asia, 2 from theAmericas, 3 from the Middle East and 22 fromEurope (BirdLife International 2001).

7. SPECIES 2000 PROGRAMME

Currently there is no comprehensive indexing sys-tem for the 1.75 million animals, plants, fungi andmicroorganisms named by science. A widely acces-sible index, will aid nations to fulfill their obliga-tions under the Convention on Biological Diversity.The Species 2000 Programme, established by theInternational Union of Biological Sciences (IUBS),in co-operation with the Committee on Data forScience and Technology (CODATA) and theInternational Union of Microbiological Societies(IUMS) in September 1994, aims to fill in this gap.The goal of Species 2000 is to “enumerate allknown species of plants, animals, fungi andmicrobes on Earth as the baseline dataset for stud-ies of global biodiversity” (Species 2000 Web siteat: http://www.sp2000.org/). Species 2000 will alsoprovide a simple access point to other species data-bases. Users worldwide will be able to verify the sci-entific name, status and classification of any knownspecies through species checklist data drawn froman array of participating databases. The Species2000 Programme has been endorsed by the UNEPBiodiversity Work Programme (1996-1997), and isassociated with the Clearing House Mechanism ofthe UN Convention on Biological Diversity. TheSecretariat for the programme is based at theUniversity of Reading in the U.K.

8. CONSERVATION INTERNATIONAL’SAQUARAP AND FRESHWATER

BIODIVERSITY HOT-SPOTS

AquaRAP is a rapid assessment methodology usedby CI “to assess the biological and conservation

value of tropical freshwater ecosystems in LatinAmerica.” AquaRAP was created in 1996 as a jointinitiative between Conservation International andThe Chicago Field Museum (CI Web site at:http://www.conservation.org.) The methodologyallows for a rapid, sample-based survey of fishes,plants, invertebrates, and water quality during 3-4weeks expeditions. So far there are two publishedAquaRAP reports, one focusing on the Pantanalregion in Brazil and one on the Upper Río OrthonBasin in Bolivia. There is also a preliminary reportfor the Caura River in Venezuela.

Recently, CI has also announced that they arein the planning process to identify the world’sfreshwater hotspots in collaboration with othernon-governmental organizations. Efforts to mapthe distribution range of a number of aquatic taxaare underway in collaboration with IUCN/SSC.

9. THE NATURE CONSERVANCY’SFRESHWATER INITIATIVE

The Nature Conservancy’s Freshwater Initiative wasestablished in 1998 with the goal to “dramaticallyincrease freshwater conservation in the UnitedStates, Latin America, and the Caribbean” (TNCWeb site Freshwater Initiative at: http://www.freshwaters.org/). The Initiative works in over40 selected sites across the Americas, where privateand public partnerships are established to “reducetwo of the most pervasive threats to freshwaterecosystems: altered natural water flows and farmrun-off pollution.” TNC’s initiative has also devel-oped a new tool for aquatic community classifica-tion, which allows users to map existing locationsof freshwater animals and their habitats acrossbroad regions and assess their relative conservationpriority. Finally, the Initiative also compiles andcommunicates the “lessons learned” from theirindividual projects and makes these available tothe wider public via meetings and conferences,training workshops, the Internet, literature, andvideo (TNC’s Freshwater Initiative Web site at:http://www.freshwaters.org)


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10. MILLENNIUM ECOSYSTEMASSESSMENT (MA)

The MA is a four-year process initiated in April2001, designed to improve the management of theworld’s natural and managed ecosystems by help-ing to meet the needs of decision-makers and thepublic for peer-reviewed, policy-relevant scientificinformation on the linkage between ecosystemsand the goods and services they provide; the condi-tion of ecosystems; the consequences of ecosystemchange and the options for response. The MA willbe undertaken at multiple spatial scales and willcover all ecosystems, including freshwater and wet-lands. The design consists of a global assessment aswell as sub-global assessments of conditions andchange in ecosystems in individual communities,nations, and regions. The sub-global componentof the MA includes numerous assessments at scalesranging from local villages to river basins designedto foster and build capacity for widespread adop-tion of integrated assessment approaches in otherregions and nations. These sub-global assessmentswill develop methodologies to carry out cross-sec-toral assessments and effectively integrate informa-tion across different scales. The MA process willalso identify important areas of scientific uncer-tainty and data gaps that hinder decision-makingand deserve greater research support (MA Web siteat: http://www.millenniumassessment.org.)

The Convention on Biological Diversity, theConvention to Combat Desertification, and theConvention on Wetlands all have endorsed theestablishment of the MA as a joint assessmentprocess to meet some of the information needs ofthe conventions.

11. GLOBAL INTERNATIONAL WATERASSESSMENT (GIWA)

GIWA is a UNEP lead initiative in collaborationwith the Global Environmental Facility and theKalamar Institute in Sweden. The assessmentfocuses on the ecological status and causes of envi-

ronmental problems of 66 transboundary waterareas, encompassing both marine and freshwater.The overall objective of GIWA is to “develop acomprehensive strategic assessment that may beused by GEF and its partners to identify prioritiesfor remedial and mitigation actions in internationalwaters, designed to achieve significant environmen-tal benefits at national, regional and global levels.GIWA will analyze the current problems and theirsocietal roots causes, and develop scenarios of thefuture condition of the world’s water resources andpolicy options. Ultimately, the aim is to providesound scientific advice to decision-makers andmanagers concerned with water resources anddealing with environmental problems and threatsto transboundary water bodies.

12. UNITED NATIONS WORLD WATERASSESSMENT PROGRAMME (WWAP)

This assessment is an initiative lead by the UN,with the Secretariat based at UNESCO. The pri-mary output is a periodic publication entitled theWorld Water Development Report (WWDR). It isenvisioned that this publication will provide an on-going global assessment of the state of the world’sfreshwater resources and their use. The firstWWDR will be launched at the 3rd World WaterForum in Japan, March 2003 and will focus on thefollowing case studies: the Chao Phraya basin(Thailand), the Greater Tokyo region (Japan), LakeTiticaca basin (Bolivia, Peru), the Peipsi lake basin(Estonia, Russia), the Ruhunu basin (Sri Lanka),the Seine-Normandy basin (France), and theSenegal river basin (Guinea, Mali, Mauritania,Senegal). The Programme also serves as an“umbrella” for the coordination of existing UN ini-tiatives related to freshwater such as, the data com-pilation done by the Global International WatersAssessment (GIWA) of UNEP, the Global RunoffData Center (GRDC) of WMO, AQUASTAT ofFAO, the International Groundwater ResourcesAssessment Centre (IGRAC) being establishedby WMO and UNESCO, the water supply and


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sanitation databases of WHO and UNICEF andthe databases of the World Bank system (WWAPWeb site at: http://www.unesco.org/water/wwap).

The focus of the programme is both surfaceand groundwater, but will link with the coastal andmarine environments as needed, for example toexamine the issues of land-based pollution andsedimentation in coastal areas. The programmealso hopes to identify water management strategiesand policies which work well; compile and synthe-size data, information and knowledge on all aspectsof water resource assessment; build capacity onhow to conduct water assessments; and provideadvice to Member States on water-related policiesand technical issues at local, national, regional andinternational levels.

13. WORLD WATER COUNCIL

The World Water Council is an international waterpolicy think tank founded in 1996 following rec-ommendations issued at the 1992 Rio EarthSummit. Its mission is to raise “awareness of crit-ical water issues to facilitate efficient conservation,protection, development, planning, managementand use of water in all its dimensions on an envi-ronmentally sustainable basis for the benefit of alllife on the earth” (World Water Council Web siteat: http://www.worldwatercouncil.org). The WWCdelineated a Water Vision to build consensusamong professionals and stakeholders to designmanagement plans that avert further water crises.In order to prepare this comprehensive vision, theWWC held regional and sectoral consultationsthat resulted in different regional and sectoralvisions, presented at the Second World WaterForum in The Hague in 2000, and which wereincorporated into the final Vision document.The regional consultations took place in Africa,North and South America, Central America andthe Caribbean, Central and Eastern Europe,Mediterranean region, South and Southeast Asia,Southern Africa, West Africa, Arab Countries,Australia, Russia, China, Nile Basin, Aral Sea Basin

and the Rhine Basin. The sectoral consultationsincluded three main themes: water for people,water for food and water for nature. These sectoralvisions were developed by different organizationsand specialists in their respective fields. For exam-ple, the Vision for Water and Nature was developedby IUCN-The World Conservation Union (avail-able on-line at: http://www.iucn.org/webfiles/doc/archive/2001/IUCN769.pdf.) In addition sev-eral other sectoral visions were developed, includ-ing visions for water in rivers, sovereignty,inter-basin water transfer, water, education andtraining, tourism and recreation, rainwater har-vesting, lakes, groundwater, and hydropower.

The WWC also created the World WaterForum. Its first meeting took place in Morocco in1997; the third one will take place in Kyoto, Japanin 2003. The WWC produces publications onwater-related issues, as well as publishes the journalWater Policy. The WWC also produces the WorldWater Actions Report, which compiles successfulactions, which affect the way water is managed.

14. GLOBAL WATER PARTNERSHIP

The Global Water Partnership (GWP) was createdby the World Bank, the United Nations Develop-ment Program (UNDP), and the Swedish Inter-national Development Agency in 1996. The GWPis a working worldwide network of partnersincluding government agencies, public institutions,private companies, professional organizations, non-governmental organizations, multilateral develop-ment agencies and others working on water-relatedissues. Its mission is to “support countries in thesustainable management of their water resources”by promoting and implementing integrated waterresources management. Its main role is to bringtogether “financial, technical, policy and humanresources to address the critical issues of sustain-able water management” from different regionsand at different management levels (local, national,regional, international, and basin-level) (GWP WebSite at: http://www.gwpforum.org).


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15. GLOBAL DIALOGUE ON WATER,FOOD AND ENVIRONMENT

The Dialogue is a strategic alliance comprising tenkey stakeholders in the areas of water, agricultureand environment, housed within UN agencies,environmental organisations, farmers associations,water research institutions, irrigation engineers andwater umbrella organisations. The goal of the dia-logue, which came out of the Second World WaterForum, is to “improve water resources managementfor food security and environmental sustainabilitywith a special focus on the reduction of poverty andhunger and the improvement of human health” bybuilding bridges between the agricultural and envi-ronmental communities on water resource issues.The idea behind the dialogue is that by bringingtogether the irrigation, environment and ruraldevelopment communities, a global consensus onthe role that irrigated agriculture currently playsand should play in the future could be reached(Dialogue Web site at: http://www.cgiar.org/iwmi/dialogue/). The main areas of work under-taken under the dialogue framework are:a) Establish cross-sectoral dialogues among key

stakeholders, at national (10 countries) andriver basin or local level (10-15 case studies)on options to achieve food and environmen-tal security to reduce poverty and hunger andimprove health;

b) Provide an enhanced knowledge base to feedthe dialogue and establish credible andauthoritative knowledge accepted by bothagricultural and environmental constituencies.Activities include the development of com-mon definitions for water, food, and environ-mental security; common indicators forpoverty, hunger, health, and environmentalquality; production of quality informationand analyses on water availability, use andrequirements for agriculture, environment andassociated uses; the development of scenariosat global, national and basin levels concerningalternative options to develop and manage

water resources for food and environmentalsecurity; and the assessment of impacts onfood security, hunger, poverty, livelihoods,health, environmental quality and biodiversityof alternative scenarios.

c) Test and evaluate innovative approaches thatenhance sustainable water security for agricul-ture and the environment via a network oflocal-and basin-level action-oriented projects,which would lead to the identification of“best practices.”

The Dialogue Secretariat is based at theInternational Water Management Institute (IWMI),in Sri Lanka. In addition to IWMI, the Dialoguepartners include the Food and AgricultureOrganization, the Global Water Partnership, theInternational Commission on Irrigation andDrainage, the International Federation ofAgricultural Producers, the World ConservationUnion, the United Nations Environment Pro-gramme, the World Health Organization, the WorldWater Council and the WWF (Dialogue Web siteat: http://www.cgiar.org/iwmi/dialogue/.)

16. CGIAR CHALLENGE PROGRAMON WATER AND FOOD

The need for the Challenge Program (CP), envis-aged as a major program of research, extension andcapacity building over a period of perhaps 10-15years, was identified through the extensive, partici-patory World Water Vision/World Water Forumprocess that ended in March 2000. The program’smission is “to increase the productivity of water forfood production and livelihoods, in a manner thatis environmentally sustainable and socially accept-able”, and it is targeted at increasing food produc-tion without increasing global diversions of water toagriculture above the year 2000 level. In terms ofgeographic focus, the CP will be directed at “ruraland peri-urban areas in river basins with low aver-age incomes and high physical, economic or envi-ronmental water scarcity or water stress, withparticular focus on low-income groups within these


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areas” (i.e. developing areas). The five inter-relatedresearch themes (and the hierarchy of subsystems inthe CP’s Food-Water System with which they arecoincident—as indicated in parentheses) for the CPdirected towards the development of objectives forfood security, poverty alleviation, improved healthand environmental security are: (1) improving theefficiency of water use in agriculture via increasedcrop water productivity (Agro-ecosystems); (2)management of upland watersheds for multiplefunctions (Upper Catchments); (3) management ofaquatic ecosystems, including biodiversity, ecosys-tem structure and function, with particular empha-sis on capture fisheries and aquaculture (AquaticEcosystems); (4) policy and institutional aspects ofwater management (Global and National Policiesand Institutions); and (5) interaction among theother four themes and synthesis of outputs(Integrated River Basin Management). Although allof these themes have direct bearing on the conser-vation and management of inland waters and theirbiodiversity, theme (3) is most central, having as itscore objective the enhancement of food security andlivelihoods by maintaining aquatic ecosystems andoptimising fisheries (Dugan et al. 2002). The theme’sresearch agenda aims to achieve this objective bydirected research into four areas: (i) policies, insti-tutions and governance; (ii) valuation of ecosystemgoods and services, and the costs of degradation; (iii)environmental water requirements; and (iv)improvement of water productivity.

A series of benchmark basins, ranging fromwithin-country to major international basins, willserve both to integrate the five major themes, aswell as to link the initiative with the complemen-tary Comprehensive Assessment of Water Manage-ment for Agriculture (SWIM2) and Dialogue onWater, Food and Environment.

It is proposed that the CP program, which hasnow reached the full proposal stage (IWMI Website, 2002) be jointly owned and lead by aConsortium of partners, which would includeFuture Harvest Centres, major National AgriculturalResearch and Extension Systems in key countries,

research institutes from OECD countries and sev-eral “NGO/private” partners.

17. COMPREHENSIVE ASSESSMENTOF WATER MANAGEMENT

IN AGRICULTURE

The Comprehensive Assessment (CA) is an inter-national research program, the primary goal ofwhich is to create a new, improved knowledge baseon all aspects of water management in agriculture,through investigating questions pertaining to wateruse (1950s to the present) and its impacts on theenvironment, poverty and food security. Theknowledge base is aimed at the information needsof poor people investing in water/agriculture solu-tions, donors and policy makers. It specificallyrecognises the need to develop both a more preciseunderstanding of the water-food-nature interac-tions in developing countries and knowledge-basedanalyses of the situation. It is expected that the pro-gram will generate several outputs, including: an asyet non-existent, comprehensive set of informationon water use in agriculture; conceptual and ana-lytic tools to assist water managers and policy mak-ers advance their strategies for water, food andenvironmental security; identification and dissem-ination of innovative solutions to increase waterproductivity in agriculture, improve health situa-tions and protect natural ecosystems impacted byagriculture; capacity building activities at multiplelevels. The CA will also interact with the Dialogueon Water, Food and Environment, in addition tothe CP and other initiatives.

The CA is organised through the CGIARSystemwide Initiative on Water Management(SWIM2), and includes partners such as CG cen-tres, FAO and others. It is a five year initiative, end-ing in line with the 4th World Water Forum, 2006.

As for all the other initiatives, the GlobalDialogue on Water, Food and Environment, theCGIAR Challenge Program on Water and Food,and the Comprehensive Assessment of WaterManagement in Agriculture initiatives have direct


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bearing on the CBD workplan for biological diver-sity of inland waters particularly in relation to thesections and subsections on basin-scale waterresource management, assessment of the impactsof water users on aquatic biodiversity, and theimpacts on and importance of aquatic biodiversityfor dependent livelihoods. The International WaterManagement Institute in Sri Lanka coordinates thethree initiatives.

18. LAKENET’S WORLD LAKESBIODIVERSITY CONSERVATION

INITIATIVE

LakeNet is a global network of more than 800people and organizations in 80+ countries, guidedby an international steering committee thatincludes regional representatives from Africa, Asia,Europe, and North and South America. In its2001 report, Biodiversity conservation of the world’slakes: A preliminary framework for identifyingpriorities, LakeNet identified 250 lakes in 73 coun-tries as initial priorities for biodiversity conserva-tion based on UNEP, WWF and Ramsar data.These lakes support globally significant fish, mol-lusk, crab, shrimp and bird biodiversity, or theyare representative examples of ancient or raretypes of lakes.

The world lakes biodiversity conservation ini-tiative began in 2000. LakeNet hosts an onlineclearinghouse of lake information at; http://www.worldlakes.org/ is providing technical assis-tance and advisory services to lake basin manage-ment groups and has started to compile online GISmaps of lake watersheds. Through a joint projectwith Living Lakes, LakeNet is conducting biodiver-sity needs assessments with partner organizationson 20 lakes. In collaboration with the InternationalLake Environment Committee (ILEC), LakeNet isdeveloping case studies and holding regional work-shops to document lessons learned in lake basinmanagement. And in collaboration with the ShigaPrefecture Government, ILEC and UNEP, LakeNet

is preparing a World Lakes Vision to guide futurework at the global level.



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Status an

d Trends of

Biodiversity of

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ical Series No.11

11STATUS AND TRENDS OF BIODIVERSITYOF INLAND WATER ECOSYSTEMS

CBD Technical Series No.Secretariat of the Convention onBiological Diversity

Also available

Issue 1: Assessment and Management of Alien Species that Threaten Ecosystems,Habitats and Species

Issue 2: Review of the Efficiency and Efficacy of Existing Legal Instruments Applicableto Invasive Alien Species

Issue 3: Assessment, Conservation and Sustainable Use of Forest Biodiversity

Issue 4: The Value of Forest Ecosystems

Issue 5: Impacts of Human-Caused Fires on Biodiversity and Ecosystem Functioning,and Their Causes in Tropical, Temperate and Boreal Forest Biomes

Issue 6: Sustainable Management of Non-Timber Forest Resources

Issue 7: Review of the Status and Trends of and Major Threats to Forest BiologicalDiversity

Issue 8: Status and Trends of and Threats to Mountain Biodiversity, Marine, Coastaland Inland Water Ecosystems: Abstracts of poster presentations at the eighthmeeting of the Subsidiary Body of Scientific, Technical and TechnologicalAdvice of the Convention on Biological Diversity

Issue 9: Facilitating Conservation and Sustainable Use of Biodiversity: Abstracts ofposter presentations on protected areas and technology transfer and coopera-tion at the ninth meeting of the Subsidiary Body on Scientific, Technical andTechnological Advice

Issue 10: Interlinkages Between Biological Diversity and Climate Change: Advice onthe integration of biodiversity considerations into the implementation of theUnited Nations Framework Convention on Climate Change and its KyotoProtocol

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STATUS AND TRENDS OF BIODIVERSITY OF INLAND WATER