M A R c H 9 91 5

Mick N. Clout (Chairman),

Invasive Species Specialist Group of

SSC/IUCNAuckland,New ZealandFax: 64-9-3737042

1

ISSG'sNWelcome to Aliens -newsletter ofthe newly-formed Invasive Spe-cies Specialist Group (ISSG) ofth~ IUCN Species Survival Com-mission. The .group aims to "re-duce the threats posed by inva-sive species to natural ecosys-tems and their native species,through increasing awareness ofinvasive species and means ofcontrolling or eradicating them".This newsletter is a contributionto that mission. It illustrates therange of threats which invasivespecies pose to the biodiversityof our planet.

The Invasive Species SpecialistGroup (ISSG) is a worldwide net-work of experts on the conserva-tion impacts of invasive species.Membership is by invitation, butit is not necessary to be a fullmember of the group to contributeto the cause of reducing conserva-tion threats posed by invasives.We provide advice on threatsfrom invasives and control oreradication methods to IUCNmembers, conservation practi-tioners, and policy makers. Thegroup concentrates on reducing

"ew s re tteror preventing the adverse effectsof alien invasions on conservationvalues.Because of the vast scope of thesubject, our activities are focusedin areas of special need. We en-visage sub-groups dealing withterrestrial weeds, water weeds,terrestrial vertebrates, inverte-brates, fish, marine invasives, mi-croorganisms, genetically-modi-fied organisms, and the interna-tional agreements and laws con-trolling invasives. There is a spe-cial overall focus within thegroup on the particular threatswhich invasive species pose tooceanic islands.Projects planned by the ISSG in-clude regular production of thisnewsletter, creation of a globaldatabase of invasive species, co-ordination of specialist work-shops on invasives, and techni-cal publications on invasivespe-cies management.

TT Ec

Aspen Meeting -USA 5Galapagos 12Model Invasion Legislation 24

Marion Island -SoutQ Africa 17Flatwonn -UK 3

Social wasps -NZ 3

Invertebrates -Hawaii ,4 Ruddy duck -Europe l0Aliens are for the Birds 22

Book Review -UK 5Upcoming events 14Newsbriefs 16Aliens to watch 19People and Projects 20Donations and Sponsorship 23

Bullfrogs -South America 6Frog Virus? -Australia 7 Miconia -Pacific ~..12

Plants -Australia 13

Melastomataceae -Seychelles...14Goats -Aldabra 8

Rocky Mountain goats- USA 8

Grey squirrels -Italy 9

Rodent eradication -NZ 15

Chesapeake Bay -US 16

Ballast water -global 18

the Edi tor

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est. Please send them to Sarah Lowe:e m a i Isjlowe@tmknov1:auckland.ac.nz; orfax: +64-9-3737042, or post to: Cen-tre for Conservation Biology, Schoolof Environmental and Marine Sci-ences, University of Auckland(Tamaki Campus), Private Bag92019, Auckland, New Zealand.

We would like this to be very mucha NEWsletter. with short itemsfocussing on new reseaI:ch and cOn-trol strategies. upcoming meetings,and other "current awareness" infor-mation related to invasive species re-search and management.We hope to publish Aliens biannu-ally. However production of furthercopies (as well as further group ac-tivities) depends on the support wereceive from both individuals andpossible sponsors (please see page23 for details of how you can help).The next issue is planned for Sep-temberl995. Contributions should bevery up-to-date. and of global inter-

Greetings from New Zealand!This first issue has been fascinatingto put together, and I would like tothank all contributors very much fortheir time and efforts. (For furtherinformation on any article, readersare asked to contact the author di-

rectly).All that remains are two requests.Firstly, please pass this newsletter onto interested and interesting col-leagues, especially those in far-flungplaces, whom we were not able tocontact first time around. Secondly,please keep us informed of eventsand continue sending in contribu-tions!

Any views or comments on the con-tent and fom'l3.t of this publication arevery welcome, as are suggestions forthe next issues.Pleas~ keep in touch, and assure thecontinued success of this newsletter.

Regards

Sarah Lowe

2

The New Zealand flatworm,Artioposthia triangulata was firstdescribed from around Christchurch,New Zealand in1895.

in 1992, since three more recordscame to light in 1993 and twentymore in 1994, some of these from asfar south as East Anglia andChristchurch, Dorset. In contrast toNew Zealand's wealth of flatwormspecies (approximately 100), Eu-rope's 8 native species le aye manyvacant niches.

parts of the world, potentially accom-pariied by more species: in New Zea-land there are many other flatwo~s,some of which might be betterequipped to prey upon earthwormsin warmer and drier climates. Ittherefore seems imperative that theinternational exchange of plant ma-terial is only allowed after the mostrigorous hygiene regulations are en-forced.

When, in the early 1960s, thisplanarian was discovered in Ireland,England and Scotland, it was con-sidered a curiosity -especially as onencountering an earthwonn it wouldseem to anaesthetise it, secrete en-zym~s to digest the prey externally,and then consume the result. Repro-duction is by a type of spontaneousceasarian birth in which its back justopens up and an egg capsule popsout.

With the Faroe Islands already in.fected, I believe Iceland is now al.lowing only the importation of bare.rooted plants.

In Ireland in the late1980s it wasshown that its presence was associ-ated with a decrease in earthwo(Innumbers. Surveys in Ireland foundit to be widespread and subsequentlyin Scotland hundreds of infected siteswere recorded throughout the coun-try, including all majoiislands. Mostof the records were from domesticgardens, but all botanic gardens andover 20% pf garden centres and nurs-eries were infected. It was alsoshown to be established in a fewfarms in the west of Scotland. Thereand in Ireland, flatwo(Ins reducednative earthwo(In numbers to belowdetectable levels, but in the east ofScotland earthworms were stillfound even after 12-15 years. Wesuspect that this is due to theflatwo(In preferring damp cool con-ditions. (In New Zealand surveyscarried out by myself in conjunctionwith Mr Peter Johns, CanterburyUniversity and Dr Gregor Yeates,Landcare Research, PalmerstonNorth have found it is confined togardens and relic woodlands in thecentre and south of the South Island).

Brian BoagScottish Crop Research InstituteInvergowrie, DundeeFax: +44-382-562426

~ ~ ~ ~ ~

EarthwofD1s play an important partin the ecology of soils in Europe. Onintensively Gultivated land in Eng-land and eastern Scotland earth-WOfD1S are probably not as numer-ous as in the grassland areas to thewest, where they play an importantpart in maintaining soil structure,drainage and nutrient cycling. How-ever any reduction of agriculturaloutput may be less important than theeffect the flatwofD1 could have onwildlife.EarthwofD1s can be the major faunalbiomass in the soil and they are of-ten a main constituent9f the diet ofmoles, shrews, badgers and evenfoxes as well as many birds eg black-birds. This issue -somewhat of a re-venge for New .Zealand, with itsstring of problem species introducedby British settlers -has captured theimagination of the British public.The Royal Horticultural Society hasdescribed it as pink-coloured andslimy, and invoked a "stamp-to-kill"policy. The general public are rightlyconcerned about the effect of thisalien.

Exotic Wasps in

N ew Zealand

Accidental introductions throughoutthe last century of social wasps fromoverseas have had a great impact onnative New Zealand ecosystems. Theearliest to arrive was the Australianpaper wasp Polistes humilis, thencame the German wasp Vespulagermanica at the end of the SecondWorld War, the common waspVespula vulgaris and finally theAsian paper wasp Polistes chinensis.These wasps are estimated in hon-eydew beech forests to compriseabout 10,000 workers per hectare,with a biomass (1097 g/ha/yr) greaterthan that for all stoats, rodents andnative birds put together. They inter-fere with the native ecosystems bydepriving birds such as the kaka (anative forest parrot) of the energyfound in honeydew. Wasps also take

So, what of future spread? Initiallyit is thought that the flatwonI1 mayhave travelled from New Zealand tothe British Isles in soil as an egg cap-sule (each contains 6-10 young).Within Britain it would seem to havespread throu~h purchase of contain-erised plants. Models predict it couldspread and become established inwestern Europe and possibly other

Recent interest has arisen since a

second record was found in England

3

many plant species exhibiting symp-toms such as chlorosis, leaf distor-tion, stunting, and death. The mostdramatic effect noted has been thephenomenon of "uluhe dieback,":the death of mono specific stands ofthe fern Dicranopteris linearis .ThisfIrst raised concern in the Manoa andPalolo Valleys of Oahu and later onKauai. Uluhe dieback has not beenobserved on Hawaii, a circumstancewhich some attribute to the charac-teristic hairiness of uluhe leaves onthat island.

large numbers of insects, particularlycaterpillars, spiders, flies and ants,and possibly also weta (flightlessrelatives of the cricket and katydid)and beetles. There is evidence ofyoung birds being killed in the nest,but it is not known how often thisoccurs.Biological control trials areunderway, and a new parasitoid

Sphecophaga vesparum burra,fromNorth America, is about to be re-leased.

Contact: Jacqueline Beggs,Landcare Research CRI ,Nelson, New ZealandFax: +64-3-546-8590

Western Yellowjacket

Vespula pennsylvanicaThe aggressively predacious westernyellowjacket wasp has the potentialfor severe impoverishment of thenative arthropod fauna in almostall except the wettest habitats in Ha-waii. This recently established

(1978) ground-nesting vespid waspproduces overwintering colopieswhich sometimes exhibit huge num-hers of workers that forage for pro-tein to feed larval workers, queensand males. Workers from a singlelarge colony of 40,000 workers maytake on the order of 40 million preyitems in a 3-week period. Availabledata suggest that approximately halfthese prey items are native arthropodspecies. Potential exists for severedepletion of lacalized endemic in-sects by yellowjacket predation. Acontrol programme, aimed at pre-venting heavy predation on nativebiota, involves a combination ofmanual nest destruction and use of a(slow-acting) bait-toxicant combina-tion which workers feed to larvae andqueens in the colony. However, thetechnique has worked well only inhigh-elevation shrubland.

Argentine Antlridomyrmex humilisThe Hawaiian Islands lack nativeants, and the native fauna (includinginsect pollinators) has not developeddefences against ant predation; thushave invasive alien ant species beenable to decimate native lowland in-sects. However the fauna at higherelevations (above 1525 m/5000 ft)was safe -until establishment thereof the aggressive Argentine antIridomyrmex humilis in the 1950sand 1960s.A species with non-flighted queens,the Argentine ant occupies two dis-junct areas between 6800 and 9350ft elevation in Haleakala NationalPark.This alien ant species has beenshown to negatively affect the locallyendemic arthropod fauna, includingpollinators. It was flfSt noted in thehigher area in 1982. Since this time,extreme fluctuations in populationsize have been noted and linked withelevation. Newly invaded areas char-

/ acteristically have high ant/ populations, whereas previously oc-

cupied range is a mosaic of persist-ent and diminished populations, ap-parently depending on microhabitat.Unless this ant species is controUed,it appears capable of spreadingwidely throughout high elevations ofEast Maui, with potentially cata-strophic effects on locally endemicbiota, including pollinators of en-demic plants. Experimental controlefforts are underway with a

hydromethylnon/protein bait, usingtechniques developed for Argentineant control in agricultural sites inCalifornia.

New Zealand's exotic wasps: clockwise

from top right: Polistes humilis,

Vespula vulgaris, Vespula germanica,Polistes chinensis.

-+

~~v v

Two-spotted LeafhopperSophonia rufifasciaPresence of the two spotted1eafuopper was first noted i.nHawaiiin 1987. Since then, this 1eafuopperhas been found in association with

Lloyd Loope, National BiologicalSurvey, Haleakala National Park.Hawaii.Fax: +1-808-572-1304

4

A workshop on "Biological Inva-sions as Global Change" was held atAspen, Colorado, from 20th Augustt9 3rd September 1994.

plans of the ISSG. including the pro-

posed global database of invasive

species. .

The meeting was organised andfunded through the Aspen GlobalChange Institute and was chaired byProf. Peter Vitousek (Stanford Uni-versity). Th~re were 25 invited par-ticipants (mostly from the USA),several of whom are members of theInvasive Species Specialist Group.

The worksilop was an excellent op-portunity to "network" with otherswho are researching or managing theconservation problems caused byinvasive species worldwide. A lot ofintangible benefits come from suchcontact and we all left the meeting alot better informed and perhaps a lit -tIe wiser. .

One tangible outcome wa~ the draft-ing by participants of a "model law"designed (by biologists! ) to reducethe global risks of biological inva-si()ns. This is now being polished byMarc Miller (see page 24) for possi-ble submission into the US legal sys-temas a proposed federal law.

The meeting included fom1al pres-entations and workshop sessions.There were also general discussionson research priorities, global prob-lems caused by biological invasions,and the potential for preventing orreducing these.I talked about the management of in-vasive species in New Zealand andoutlined the general mission and

Mick Clout

(Chair, ISSG)

Book ReviewsII Biological Invasions "

Professor Mark Williamson at the University of York, is currently completing his book entitled "Biological Invasions",to be published by Chapman arid Hall in their "Population and Community Biology" series early in 1996.Some biological invasions have marked ecological and economic effects. But most fail, and of those that succeed, mosthave little impact. Based on sound analyses, and with many illustrative examples, this 'book deals with the causes ofinvasion success and failure, and with the consequences of success.

It is the first structured overview of the subject since Charles Elton's 1958 classic The Ecology oflnvasions by Animalsand Plants and it draws on the extensive results of the SCOPE programme on the ecology of biological invasions( 1982-1991 ); All invasion stages are covered, from arrival through spread to ecological equilibrium.

Invasions have much to tell us about population and community ecology, and their study involves a good deal ofnatural history. This book should appeal to professional ecologists, conservationists and many amateur naturalists.Importantly, the consequences of release of genetically engineered organisms -a topic of current concern to manyinvolved with environmental problems -are considered.

Submitted by Michael Usher, Scottish Natural Heritage,Fax.: +44-31-446-2405Contact: Mark Williamson, Department of Biology, University of York, York YO1 5DD, UK.

5

ond ongoing problem is that new b\;lllfrog farms orintroductions are still being established. The possi-biliry of ranching bullfrogs has recently been con-sidered in Paraguay.

One of the spin-offs of the human consumption offrogs' legs is the establishment of the North Ameri-can buJlfrog, Rana catesbeiana, outside the species'normal range. Naturally this species is foundthroughout much of the eastern and central UnitedStates. Although the western boundary of the spe-cies' natural range is bounded by the Rocky Moun-tains, other factors limiting its distribution are notyet fully understooQ. However, direct introductionand escape from frog (arms have allowed this spe-cies to become established in many countries. In-trodu.ctions have been made in the Western US,Western Canada, Mexico, Cuba, Jamaica, Ecuador,Colombia, Italy and Taiwan. Bullfrogs have alsobeen spread via tadpoles being transferred with fish,during translocation of fish stocks in fisheries op-erations.

The frogs are relatively large and are voraciouspredators of a variety of prey items, feeding on ilny-t~g that moves, and that they can swallow whole,including other frogs, snakes, and small turtles.Documentation of the spread of bullfrogs has beenaccompanied by the observed declines and disap-pearance of other anurans. It is often difficult to dem-onstrate that bullfrogs are the direct cause of thede-cline, and if they are, the exact nature of the interac-tions between the species concerned may also beunclear. Bullfrog larvae may outcompete those ofother species, or adult bullfrogs may eradicate otherspecies by predation. However, what is clear is thatthe coincidence of the spread of bullfrogs and thedisappearance of otherfrog~ has been repeated toofrequently to allow much doubt in the minds of am-phibian workers that introduced bullfrogs damagenative frog populations.

Last October this office received a request for helpfrom Aida Luz Aquino at the CITES office in Para-guay, where bullfrog ranching was being proposed.We provided statements advising of the potentialproblems. -

Meetings with the department of wildlife have takenplace. The department of wildlife will consider theintroduction of bullfrogs to enclosures, that are SU;p-posed to be escape-proof. However, Ms Aquino isconcerned that once frogs are sold-on from theseestablishments, there will be no control over thein.Moreover, she thinks that bullfrogs have alreadybeen introduced into Paraguay, although no officialpermits have been issued.I would add to her expressed concerns, since I tNnkthat it is very difficult to guarantee that there willbe no escapes from such 'farms' or 'ranches'.Whenit is considered that many other farming operationshave failed in th~ past (presumably on economicgrounds) it seems that starting a new venture inParaguay is not worth the risks involved.

"The vision of bullfrogs becoming

established in South American

countries is alarming".

The potential for bullfrogs to become firmly estab-lished in tropical areas is enhanced by by the accel-eration of of their life cycle: the larval stage, whichin North America can last one, two, or more, years,can be reduced to as little as two months in warmerclimates. Clearly, increasing the speed of populationturnover will also lead to the potential for rapid colo-nisation of new areas, with consequent dire resultsfor native fauna.

The problem is ongoing in two respects. Firstly, nowthat hetpetologists are closely examining the statusof amphibians, declines attributed to bullfrog intro-ductions are becoming more evident, or perhaps arereceiving more attention. For example, in a verycomprehensive study of the status of amphibians inDickinson County, Iowa, (published by MikeLannoo and colleagues last year), it transpired thatone species, Blanchard's cricket frog, had completelydisappeared. This was probably due, in part, to thespread of bullfrogs. In addition, the authors regardbullfrogs as the most immediate threat to existingnative amphibian populations in that area. The sec-

John Baker, Declining Amphibian PopulatiQns TaskForce

(DAPTF), UK

Fax: +44-908-654167

6

pIe, the clear south-to-north pattern in the spread of thedeclines, and the sudden and unexpected disappearancesof monitored populations, certainly are consistent withthe expected effects of a novel pathogen.The disappearing species are all strongly associated withstreams, which suggests the pathogen is being carried bywater, although it is likely ~at other vectors (such as bit-ing insects or aquatic birds) may also carry the disease:Sick and dying frogs from several populations have ex-hibited very similar symptoms, and the results of clinicaland immunological studies are clearly consistent withviral disease -particularly those caused by certainiridoviruses -although the specific pathogen has not yetbeen isolated.One of the most intriguing patterns is that the declineshave been highly selective; som'e species have disap-peared, while a few other species from the same streamshave remained unaffected. This pattern is consistent withthe behaviour of viruses, which often exhibitextieme hostselectivity. A second interesting phenomenon is that, inthe tropics, several species have disappeared from coolupland areas but are still persisting in the warmer low-lands. We believe this may be due to higher temperatures,which are known to enhance the immune responses ofcold-blooded animals like frogs, and may also exceed thespecific thermal tolerances of the virus.If we are right about the deadly frog virus, then wheredid it come from in the first place? We do not know theanswer, but the striking similarities of the Queenslandfrog declines to those occurring overseas caJ:tnot be ig-nored. We postulate that the virus is exotic to Australia,and that it may have been introduced as a result of thethriving international trade in ornamental fish. Quaran-tine procedures for these fish are often minimal, and inseveral cases exotic bacterial or viral pathogens have beenisolated from specimens that were due to be imported. InQueensland, as ersewhere, aquarists have released exoticfish into the wild on many occasions.Our conclusions highlight a type of environmentaldeg-radation that may be widely under-appreciated -the glo-hal spread of foreign pathogens. Given the potentiallyrapid evolution of most pathogens and the remarkablemobility of modern technological society, exotic diseasesmay increasingly threaten the integrity of many natural

ecosystems.

Amphibian populations are declining rapidly allover theworld. In many cases, the causes are apparent: loss anddegradation of habitats, water pollution, and introductionsof exotic predators or competitors, among the prime fac-tors.But during the past 25 years or so an entirely differenttype of decline has been occurring. On at least three, andpossibly six, different continents, frogs that breed and livenear mountain streams have suddenly and mysteriouslycrashed. In many cases, the frogs were common and foundin remote, virtually pristine habitats. Often, the crasheswere so unexpected and sudden that biologists werecaught entirely flat-footed.Fortunately, in Queehsland, Australia, a handful of dedi-cated frog biologists such as Keith McDonald and GlenIngram, have spent countless rainy nights during the pasttwo decades wading through remote mountain streamswith flashlights in hand, meticulously identifying andcounting every frog they encounter -to compile what isprobably the world's most exhaustive record of declin-

ing frog populations.In the past few years, biologists studying the mysteriousdeclines of upland frogs have often suggested that thes~frogs may be acting like-"canaries in the coal mine" -

warning us of some type of subtle but large-scale envi-ronmental deterioration. Factors such as acid rain, pesti-cide residues in fog, unusual weather patterns, and in-creasing UV radiation due to progressive erosion of theozone layer, have all been proposed as possible causes.But in Queensland, we have been able to discount nearlyall of these possibilities. The declines here are as dra-matic as those witnessed anywhere -at least 14 specieshave crashed, with half of those believed to be extinct.The first declines were documented in1979 by GlenIngram at the aptly-named Tragedy Creek, in theConnondaleRanges near Brisbane. Five species declinedin that area, with one of the world's most unique amphib-ians, the southern gastric brooding frog {Rheobatrachussi/us), which swallows its eggs and broods them in itsstomach, disappearing entirely.Since then, the declines have swept northward along theGreat Dividing Range, at an average rate of about 100kilometres per year, according to our calculations. As aresult of careful monitoring, we know now that appar-ently healthy frog populations can disappear entirelywithin a period of only a few weeks.What has caused these dramatic crashes? We believe thatthe most plausible explanation is that a highly virulentpathogen -possibly an exotic virus -is responsible. Sev-erallines of evidence support this hypothesis. For exam-

William F. Laurance

CS/RO Tropical F orest Research Centre

Atherton, Queensland, AustraliaFa.\": +6/-70-9/3245

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Aldabra Atoll is a World HeritageSite -an uplifted cor~l atoll belong-ing to the Republic of Seychelles,and a living history museum. Unlikemost tropical islands, Aldabra is stillnearly pristine. It is an impotantbreeging base for many kinds ofseabird, and the home of the white-throated rail, Dryolimnas cuvieri, thelast flightless bird in a part of theworld once famous for the dodo.Aldabra is also home to the rareAldabran brush warbler {25 birdsremain) and the last pristine popula-tion of Indian Ocean giant tortoises,Geochelone gigantea. In the 1970sa research station was built and fi-nally the atoll was declared a WorldHeritage Site under the United Na-tions' World Heritage Programme.Though feral goats have been at largesince sometime in tbe last century,the ecological damage caused bythem -destruction of the plant life,to a 2-metre-high browse line, in-cluding vegetation that birds use fornesting, and shade that giant tortoisesneed to survive in the blazing hotclimate -wasn't fully recognizeduntil I visited the atoll in1987. Thatyear, and the next, we killed a littleover 900 of the goats, with the ex-pectation that the Seychellois mili-tary , several of whom we had trainedfor the task, would continue the con-trol. Over the next se:veral years itbecame evident that the controlwould not be continued, and so TheWorld Bank included the eradicationof goats from Aldabra as part of theenvironmental action plan for theSeychelles. A couple of hundredother islands around the --worldshould only be so lucky. I was con-tracted by Seychelles Islands Foun-dation to direct the project.

Goats were thriving on three of thefour large islands that comprise theatoll ring when the project began:

Fax: +1-503-737-3590

E- mail :coble nfb@ccmail. or sf. edu

8

The key to eradicating goats is ef -

fectiv~ location of survivors once themajority of the population has beenkilled. The survivors are generallyquite wary, and are also difficuJt tolocate simply because there are sofew of them in an area.We used the fairly simple "Judasgoat" technique, which relies uponthe seeming obligate nature of goats ,

gregariousness, from the very begiQ-ning of the project. Goat~, simplyput, hate to be alone. When they findthemselves alone, they set out to lo-cate conspecifics, and they are muchbetter at it than humans, With a ra-dio affixed, such a goat, released inan area of surviving goats, is likelyto locate them in a fraction of thetime it takes a human. A human maythen track the radioed goat with a di-rectional antenna and figure a wayto sneak up on it and kill the non-radioed goats. The Judas goat is leftunharmed to go off and "betray"some new friends, and the process isrepeated until no new goats are con-tacted.Based upon repeated follow-upsearches that have revealed no signof living goats, we believe we wereable to completely rid two of the is-lands (Picard and Malabar) of goatsusing this technique.As I write, the effort is nowconcen-trated on the largest island (GrandeTerre) where the eradication has beenin full swing since December1994.Continued improvements with Judasgoats mean we can more rapidly, andat Jess cost, eradicate feral goats andthus protect a wealth of insular en-demic species, plant and animal,worldwide.

Bruce CoblentzDepartment of Fisheries and Wild-life, Oregon State University

Goats

Rocky Mountain goats (Oreamnosamericanus) in the Olympic NationalPark, Washington, continue to gen-erate controversy. The U.S. NationalPark Service would like to controlthe goat's population as their tram-pling and foraging activities areknown to be altering the region 'sfragile alpine and sub-alpine ecosys-tems and possibly endangering somerare plants. Since the biota of theOlympics had evolved in freedomfrom alpine ruminants, the herba-ceous vegetation and the soil soonshowed significant negative effectsof the goats. Lichen cover was dis-appearing and numerous eI:ldemicplants were threatened.However two recent articles in thejournal Conservation Biology h~vequestioned the "introduced" status ofthe goats, thus bringing into questionproposed plans for controlling oreliminating the population.Cathy Sue and Roger Annunsen, rep-resentatives of the Fund for Animals,an animal rights organisation, andLee Lyman, an anthropologist fromWashington State University, sug-gest that the Olympic MouPtaingoats'rnay have colonised the Olym-pic Mountains prior to a well-docu-mented introduction in the mid-1920s. The goat population has since

'-.Increased dramatically, and byl983there were an estimated 1200 in thepark. Control actually did begin in1981 and between then and 1989,509 animals were removed, mostlyby live capture.Sue, Annunsen, and Lyman 's theoryis based largely on an 1896 NationalGeographic article which lists moun-tain goats among the fauna indig-enous to the region. However, evi-dence supporting the National ParkService's position is even more con-vincing, including: (1) the long term

isolation of the Olympic Mountainsby salt water on three sides and low-lands on the fourth; (2) the absencein the Olympics of several other spe-cies of sub-alpine and alpine mam-mals that are found in the CascadeRange ( eg. the pika, hoary marmotand bighorn sheep); (3) the presenceof many endemic animals and plants;and (4) the lack of sufficient physi-cal evidence (eg. fossil artefactsmade from mountain goat hair, bone,horn, wool) or historical accountsconfirming the presence of this spe-cies prior to its introduction in themid-1920s.

Michael Hutchins, American Zooand Aquarium AssociationFax: +1-301-907-2980

Bruce Cobleiztz comments:"Underlying the proximate issuehere is a terrifying ultimate iss~e,namely the legitimacy of exotic or-ganisms. What usually happenswhen an exotic is in place for someperiod of time is that people growup familiar with that organism andsimply cannot imagine the environ-ment without it. The organism hassimply become normal fauna or florain the mind of the average person.JHow does one combat a person's

comfortable familiarity?"

The Stupinigi park is typical of theareas the squirrel has colonised, withits approximately 900 ha. composedof 470 ha. of mixed woods in badcondition (mostly Quercus robur)with a thick shrub layer, in great parthazel, and the woods being frag-mented by commercial poplar plan-tations (180 ha.) as well as meadows,maize and wheat fields. The sur-rounding plain, crossed by many ca-nals and rivers, is ex~ensively culti-vated, mostly with cereals and pop-lars. There are a few small naturalwoods of Q. robur, Carpinus betulus,Ainus glutinosa, Robiniapseudacacia, and Acer campestre,generally along water-courses withseveral thickets in the cultivated area.

The risk that the grey squirrel couldspread through Italy makes an eradi-cation campaign particularly urgent,though finance may be a problem.Obtaining funds necessary to pay fortraps, poison bait and personnel willbe difficult. as Italian authorities donot prioritise agriculture, forestryand landscape. It will perhaps beeasier to put into force legislationprohibiting the translocation of ro-dents within the Italian borders.

,{j;

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This should be the first step towardsthe solution of the grey squirrel prob-lem in Italy.An application for an eradicationprogramme is being made to the Eu-ropean Commission with the partner-ship of Great Britain and Belgium.

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"('"1'I;'C , ,,' ' , "J fi, ' 1 " j"",. -.',

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The farthest point from the releasesite where the grey squirrel has beenfound is the park 0( Racconigi, anold royal residence of 170 ha. com-pletely enclosed by a wall.

Italo CurradoUniversita degliStudi dl TorinoFacolta dt Agraria, Torino, Italy.Fax: +39-11-668-7016

:.1;

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0

The first North American grey squir-rei (Sciurus carolinensis Gmelin)arrivals in Italy had a royal welcome.

The two pairs from Washington DCwere deliberately introduced into theRoyal Park at the Castle of Stupinigi,south-west of Turin. Since then therodent has established successfullyin the broadleaved woods of the park,and slowly spread into the surround-ing plain, now inhabiting an area of250km2 where it causes extensive,damage to plantations and cereal

crops.A second Itillian grey squirrel popu-lation can be found near Genoa,where five individuals from Norfolk,Virginia, USA, were released in1966. The Piedmont grey squirrelinhabits a mainly flat area, with aneJevation range from 230In to 260m.

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'i" /7

Oreomnus omericonus

As has happened in the UK, the na-tive red squirrel (Sciurus vulgaris L.)has been displaced from a great partof the territory occupied by the greysquiuel and is present only in thezones of more recent colonisation:The area occupied by the grey squir-rel around the park of Racconigi doesnot seem to be linked to the rest ofthe occupied area, in fact there aresome parks and woods between bothareas where this rodent is absent.This leads us to suppose that the greysquirrel was introduced into this parkseveral years ago and especially inthe latest years it has become numer-ous. Such introductions are not iso-lated .occurrences, in fact there aremany reports of grey squirrelliberations, but in many cases theyhave disappeared, possibly que to cat

predation.

Birds (especially flighless ones) seem particularly vulnerable to invasionsbut they are not always the victims.America's ruddy duck Oxyura jamaicensis is a new threat to the genetic integrity of Europe's white-headed duck Oxyura leucQcephala.

The North American species was introduced to Britain where it first bred incaptivity in 1949 at the Slimbridge Wildfowl Trust Centre. The first youngwere reared the following year, but were able to escape in 1952 as they hadbeen left full-winged. No feral breeding was recorded in Britain unti11960. Afurther 90 birds may have escaped from Slimbridge up to 1973 and othershave undoubtedly escaped or been released from other waterfowl collectionsin Britain, but the number of birds involved is unclear.

Since the first breeding record in 1960, there bas been a dramatic increase inthe size of the British population of ruddy ducks which now numbers some3500 birds (data from The Wildfowl and Wetland Trust's (WWT's) NationalWaterfowl Counts (NWC) Scheme) and a corresponding increase in the numberof continental records. A PhD study on the ecology and behayiour of ruddyducks and its interactions with native british waterbirds has recently beencompleted at the WWT. This has shown that, although there appears to be noserious competitive interaction between ruddy ducks and other species in theUK, given the present population size, there is potential for competition in thefuture if the current population increase continues. The potential for rapidcolonisation of mainland Europe is foreseen, as in Britain the ruddy duckappears to be exploiting a vacant niche.

The only population of white-headed ducks in Western Europe is found inSpain and its existence ha:s depended heavily on recent conservation meas-ures and re-introduction programmes~ The success of this effort is reflectedby the increase in peak counts of birds in Spain from 22 in 1977 to 786 in1992. Conservation and re-introduction initiatives are also underway in Italy,France and Hungary.

The ruddy duck was first recorded in continental Europe in Sweden in 1965and has now been reported from at least 14 European countries (Belgium,Denmark, Finland, France, Germany, Great Britain, Iceland, Ireland, Italy,The Netherlands, Norway, Spain, Sweden and Switzerland). Most of theserecords come from France where at least 89 birds had occurred up to andincluding 1990. Between December 1989 and July 1991 there were 29 recordsof ruddy ducks from ten wetlands in the main Andalucian breeding areas ofwhite-headed duck in Spain. Ruddy ducks are known to have bred su<:cess-fully on the continental mainland at least seven times: once in Holland in1977, twice in France in 1988, twice in Spain in 1990, once in Spain in 1991and once there in 1992. Young were also successfully hatched in Iceland in

10

1991. In view of the above infonnation and the continued increase in thebritish population of ruddy ducks, it seems likely that colonisation of main-land Europe will occur over the next decade.

The high degree of niche overlap between the ruddy duck and the white-headed duck will result in direct competition between the two species. Hy-bridisation will also be a serious problem. The first-known ruddy duck x white-headed duck hybrid was reported in Britain in 1980 and hybrids have subse-quently been reared in WWT collections of captive waterfowl. These hybridsare now known to be fertile and capable Qf breeding both with other hybridsand with white-headed ducks. At least ten hybrid ruddy duck x white-headedducks have been reported from the breeding grounds of the white-headed duckin Spain. On Rincon Lagoon, Cordoba, both hybrids and pure ruddy duckshave been found to be more aggressive than native white-headed ducks, anddominant over males during courtship. They were also dominant over allwaterfowl with which they were observed, including little grebe Tachybaptusruficollus, mallard Anas platyrhynchos, gadwall A. strepera, pochard Aythyaferina and coot Fulica atra. In view of this information, the threat which theruddy duck poses to the Spanish, and indeed the world populatio-n of white-headed duck, cannot be overstressed.

Ruddy ducks are already controlled in Spain. But without control measures inGreat Britain, further colonisation of the continental mainland will occur morerapidly, with the real danger of extinction of the white-headed duck.

Alison StattersfieldBirdLife International, Cambridge, UKFax: +44-/223-277200E-mail: birdlife@gn.apc.org

A

J~~

~

, .'- s. ,',-.:

: ",-;,"

.."'

11

While most of the biodiversity of the Galapagos Islandsis intact, it is under increasing threat from introduced orinvasive species. Unless action is taken, much of theunique native flora and fauna will be destroyed.

Goat~ Caprahircus have long been a problem, and whileseveral smaller islands including Santa Fe, Marchena,Pinta and Espanola were cleared of goats on the 1970s,the animals were introduced onto Volcan Alcedo in theearly 1980s and now number many thousands. Their de-struction of the vegetation is of immediate concern asAlcedo is the home of the largest population of giant tor-toises. The goats have now spread to Volcan Darwin im-mediately north of Alcedo and may already have reachedVolcan Wolf, the northern volcano on Isabela.There are at least two species of recently introducedwasps, one of which is as yet unidentified, and these areposing an increasing threat to the wildlife and an incon-venience to the human population. The smooth-billed aniCrotophagus ani (family: Cuculidae) has multiplied topossibly 5000 individuals, and poses a serious threat tofinches and lizards.Introduced plants are possibly th.e most serious threat andhardest to eradicate. Lantana camara is a serious prob-lem on Floreana, where it is becoming dominant and de-stroys the nesting sites of the dark-rumped petrel. TheQuinine Cinchona succirubra and Guava Psidiumguajava trees on Santa Cruz are rapidly taking over themiconia zone (Miconia robinsoniana -endemic) and thefull impact of the 1982-83 El :Nino year is becoming ap-parent with more introduced plants, including trees,spreading out of the farming zone into the national park.Rats are a continuing threat, especially to the breedingpopulations of Hawaiian petrel on Santa Cruz andFloreana. The arrival of the brown rat is a serious devel-opment as it is much more aggressive than its black cousin.Invasive species are without doubt the major threat to theGalapagos and a concerted effort is needed to eliminatethem. As yet there are no effective control and quaran-tine measures in place so the number of invasive speciesis likely to increase in the short term.

Jean-Yves Meyer

Delegation a I' Environnement, Tahiti

Fax; +689-41-92,-52

Julian FitterGalapagos Conservation Trust, UKFax: +44"1747-855131

12

The native flora of tropical oceanic islands is well knownto be pat:ticularly susceptible to displacement and evenextinction by alien introduced species. Since its introduc-tion to Tahiti in 1937 as an ornamental .with attractivepurple and green foliage -Miconia calvescens DC(Melastomataceae), a small tree native to CentralAmerica, has become a dominant invasive plant in theSociety Islands (French Polynesia, in the South Pacific

Ocean).It has spread over two-thirds of the island of Tahiti in allmesic and wet environments (> 2000 mrn/year), up to 1300m. M. calvescens forms dense monotypic stands that com-pletely displace native forests (40% of the Tahitian en-demic plants are directly endangered). It has also reachedthe surrounding islands of Moorea and Raiatea. Cbntroloperations using manual uprooting were carried out onthe island of Raiatea in 1992 and 1993 (over 250,000plants were destroyed). Collaboration with Hawaiian bi-ologists (Haleakala National Park of Maui and HawaiiDepartm~nt of Agriculture) has been initiated in order tofind efficient control methods (including bio-control)against this plant pest that represents a potential dangerto the rainforests of all tropical oceanic islands.

Plants.

tn

Among the greatest of threats to Australia's biodiversityis the spread of non-indigenous plant species. Almostevery major ecosystem has been extensivel:y altered, anddegradation continues as these species infill and expandtheir range.

spread communities and habitats for animals. Weed in-vasion can place these fragments at great risk. For exam-ple, exotic grasses typically invade road verges and clear-ings, and the thick growth precludes regeneration of na-

tivespecies.Invasion by grasses (e.g. Molasses grass Melinisminutiflora in the wet tropics and Ehrharta calcyna insouthwestern Australia) can also increase the probabilityof hot, frequent fires which typically favour further en-croachment of the grass into native vegetation. Rainfor-est is typically highly resilient to invasion until it is frag-mented. Edges become infested with large numbers ofsun-Ioving exotic vines (eg. blue thunbergiaThunbergiagrandiflora, potato vine Anrederacordifolia. balloon vine

Cardiospermum granliiflorum, Ipomoea spp., creepers(eg.Tradescantiaalbiflora ), shrubs ( eg.lantanaLantanacamara, privet Ligustrum lucidum) and gras!i.es ( eg.molasses grass Melinis minutiflora).

The habitats most at risk are the watercourses. These mesicareas tend to support a much greater variety and densityof non-indigenous species than the surrounding landscape.They also tend to be sites of higher native species diver-

sity.

The ecosystems which appear not to have serious weedproblems are mangrove flats, alpine areas and the redsandy deserts of central Australia. Intact areas of uplandrainforest are remarkably resilient to invasion, and tem-perate forests, if they are not fragmented, are not highlysusceptible to invasion.

Over eighteen species of non-indigenous species havebeen identified to be of national significance to conser-vation. Among these is the vine blue thunbergia whichsmo~ers lowland wet rainforest edges eyentually killingthe trees and progressively pushing back the forest edge.The intensity and scale of impact has led to focussed con-trol programs, and thunbergia could become one of thefew success stories in weed control if the current impetuscontinues.

Broad-scale, single species invasions tend to dominate inthe extensive grazing country of northern Australia. Graz-ing, which is usually accompanied by changed fire man-agement, induces drastic direct or indirect changes to thenatural ecosystems-. The disturbance over much of therangelands predispose& these vast areas to invasion byexotic species many of which were originally introducedfor shade or fodder. Exotic trees aDd shrubs are now dis-placing native vegetation over thousands of squarekilometers. Among the more aggressive tree/shrubs areprickly acacia Acacia nilotica, rubber vine Cryptostegiagrandij1ora, parkinsonia Parkinsonia aculeata, mesquiteProsopis spp., and giant sensitive plant Mimosa pigra.Not one of these plants is under control continent-wide.Given the vast distances, the low human population avail-able for management, the low economic value of the landcombined with the expense of control the most intracta-ble weed problems in Australia are these Qf the northern

rangeJands.

-\ft

The shtub-vine known as rubber vine Cryptostegiagrandiflora smothers natIve trees and shrubs along manywatercourses in monsoonal Queensland, particularlyalong the rivers flowing into thequlf of Carpentaria whereit is displacing gallery forests which have not even beenbiologically surveyed. This plant chas infested over350,000 square kilometers of north Queensland and isthe subject of biological control trials.

The vigorous tree-shrub pond apple Annona glabra , isgradually displacing the broad-leaf mela!euca woodlandson the wet tropical coast of northern Que;ensland. It fbrmsa thick understory and prevents regeneration of themelaleuca. Pond apple is now the priority species formanagement in the Wet Tropics World Heritage Area.

In the eastern and south-western parts of the continent amosaic of multi-species invasions is the dominant pat-tern. In these more populated parts of Australia the veg-etation is highly fragmented. The fragments can be re-positories of rare species, the last vestiges of more wide-

13

Giant sensitive plant Mimosa pigra is forming dense,monospecific and impenetrable thickets on the floodpainsof the tlTop End" in the vicinity of Darwin. Although thesubject of biological and chemical control efforts, the riskof it spreading to clean ate:as in the World Heritage Areaof Kakadu National Park and the Aboriginal Arnhem Landis still high.

Ponded pasture grasses such as para grass Brachiariamutica have escaped from target pasture areas to chokeshallow wetlands and creeks in the wet and wet-dry trop-ics. Brachiara and more recently planted larger pasturespecies are threatening the viability of these continen-tally restricted aquatic and waterfowl habitats. Thesegrasses like many grass species continue to be plantedand there is unresolved conflict between primary produc-tion and conservation interests.

Species of Melastomataceae infi"oduced to the SeychellesIslands and discovered in the early 1990s are being moni-tored on a semi-annual basis.

The changes in structure found will be described in de-tail in the forthcoming issue of Phelsuma, the annualjour-nal of the Nature Protection Trust of Seychelles.

Even the marine environment is not weed fl-ee. Along theeastern Tasmanian coast, a giant Japanese kelp Undariapinnatifida has established from spores carried in withballast water. The species produces millions of spores perplant per day and could potentially infect rocky substratealong the entire Australian coastline from Cape Leeuwin,Western Australia to Wollongong, New South Wales.

Two important species are Memecylonfloribundum andClidemia hirta.

Domination of the fonDer on Mahe (achieved throughslow growth in deep shade) results in habitats with verylow plant and animal species diversity.

.Clidemia hirta dominance on Silhouette has been dra-

matic in appearance but provides a broadly natural habi-

tat for the indigenous fauna. In the past 4-5 years its

canopy has opened out and natural regeneration of the

vegetation is occurring.

The linkages between human activity and invasion bynon-indigenous species have been increasingly recognisedby managers and policy makers. The scale of the prob-lem dictates that direct control by mechanical and chemi-cal means can only be effective at a local and possiblyregional scale. Integrated management which empllasisesprevention, appJies direct control judiciously and incor'-porates modification of land use and nlanagenlent is theonly strategy with some long-term possibility of success.

Justin Gerlacll. Nature Protection Trust of Seychelles, UKE-mail: klclOO1@esc.canl.ac.uk ,

A national milestone toward addressing weeds in an iri-tegrated way is through the recent development of a Na-tional Weed Strategy. The National Weed Strategy in-cludes a recommendation to modify current plant importprotocols to decrease the risk of importing new problemspecies. The Strategy and new import protocols are stillto be endorsed by the Australian government.

Stella E. Humphries,CSIRO Division of WildlifeLyneham, ACT, AUSTRALIAFax: +61-616-241-3343E-mail: S.Humphries@dwe.csiro.au

and EcoJogy

Ballast Water SymposiumInternational Council for the Exploration ofthe Sea (ICES) Annual Meeting in Aarhus,Denmark. September 1995.Information: General Secretary, ICES, 2-4Palaegade, Copenhagen, Denmark.

14

Charles Darwin Foundation Symposium:Theme -Invasive Species -Research, Manage-ment and Elimination.Royal Society, London, UK. 6 Apri11995.Information: Julian Fitter, Fax: +44-1747-855131

Rodent E radication

Zealand I standsfidently cleared of a single speciesof rodent. The main advantage of thismethod is that only target specieshave access to bait. A disadvantageis that it is extremely labour inten-sive. There are also problems withspecies-specific dominance aroundbait stations between two or morespecies of rodent and age-specificdominance within species.

come. To date all eleven islandstreated with aerial applications havehad few nomarget problems, a claimsupported by pre- and post-monitor-ing of a variety of birds.

Rodent eradication in New Zealandhas been very successful during thepast 15 years. This has been hailedin some quarters as some sort ofmiracle. However the simple fact ofthe matter is that the populations ofrodents being dealt with are naive.In most cases this rodent eradicationhas been on uninhabited offshore is-lands where only one species ofro-dent, which has never encounteredtoxins, is present. These operationshave all proven to be relativelystraightforward with the only logis-tical problem being the remotenessof the islands. In addition, the adventof second generation anti-coagulantslike brodifacoum and bromodralonehave made the task easier. And it isthe delayed action of such toxins thatis their secret to success. Two meth-ods of eradication have evolved dur-ing the past 15 years each with itsown advantages and disadvantages.

Aerial application:

In essence this relies upon saturation

poisoning. The bait used is readily

broken down by weathering, the

toxin by micro-organisms in the soil.

A helicopter with a bait spreader

slung underneath is used to deliver a

swath of bait on parallel transects

over the entire island: A global posi-

tioning system (GPS) should ensureaccurate bait coverage is achieved.

This enables extremely large islands

to be treated in a matter of hours, and

today we are looking at islands of up

to 3000 ha., possibly up to 11,000

ha. The distinct advantage of this

method is that all target animals have

access to the bait from day one. This

is of particular significance where

two or more species or rodent are

present. However the one real dis-

advantage of aerial broadcasting is

that bait is readily available to non-

target species.

.

Bait stations:

This method was first used on a

group of islands commonly known

as "The Noises" in the inner Hauraki

Gulf, off Auckland. Bait stations

were set out on a 50m x 50m grid

over each island arid checked fre-

quently for several months. Eradica-

tion was a long process, but this op-

eration stands as the first deliberate

eradication programme and was a

valuable testing ground. Based on

this method there followed success-

ful eradication programmes on nu-

merous islands and their adjacent is-

lets or rock stacks. The size varied

from 0.2 ha. stacks to islands of 170

ha. The situation today is that any is-

1and up to about ~50 ha. can be con-

Almost totally dependent upon the

ability to eradicate rodents are nu-

merous threatened species recovery

programmes. Here in New Zealand,

many critically endangered speciesjust cannot co-exist with rodents. Our

ability to continue to fine-tune eradi-

cation methodologies wi!1 achieve

two aims. The creation of more ro-

dent-free habitat is paramount; of

almost equal importance is the abil-

ity to eradicate rodents if they invade

those all-important refuges which are

currently rodent-free. This has often

happened in the past with ship-

wrecks.

As we moye towards larger and more

complex islands, contingencies for

non-target species are being devel-

oped. At present considerable mo-

mentum has been created, island res-

toration is now possible, and there is

a worldwide interest in these devel-

opments.However there is a word of.caution.It has taken 15 years of constant ef -

fort by only a few individuals to

reach this stage. It will take only a

few individuals and a short time to

slow down this momentum if these

proven methodologies are not fol-

lowed and eradication attempts fail.There is always a risk -to scaven-

gers and in particular raptors -of sec-

ondary poisoning from rat carcasses.

But this happens regardless of bait

application method. Primary poison-

ing from non-target species eating

bait can be a much more serious

problem which is not easily over-

Ian McFadden

New Ze(Jland Department OfCol1ser

)'atiol1, Aucklal1d

Fa.\": +64-9-377-2919

1~

Chesapeake Bay Ballast StudyThe introduction of nonindigenous aquatic species into coastal waters worldwide is having profound ecologicaland economic impact upon recipient communities. In recent years, the principal medium fQr transport of exoticspecies has been ballast water in ocean-going ships. ,

SinGe 1993, scientists at Williams College-Mystic Seaport, Connecticut, and the Smithsonian EnvironmentalResearch Center, Maryland have been collaborating on a muJtifaceted research program that examines the sus-c~ptibility of estuarine sy.stems to invasion by nonindigenous species and gauges the ecological impact of inva-slons. .

We have focused our efforts on Chesapeake Bay, the largest and most productive estuary in the U nitedStates. Incomparison to other systems ( e.g. San Francisco Bay, the Great Lakes), Chesapeake Bay has relatively few docu-mented invasions. Possible reasons for this discrepancy include: (1) ballast water assemblages reaching ChesapeakeBay differ froin those entering other invaded systems; (2) Chesapeake Bay is resistant to invasion because of asyet unidentified physical or biological characteristics; (3) Chesapeake Bay has in fact been invaded but theseinvasions have not been documented.

.Our results show that ports in Chesapeake Bay receive more ballast water (>3 billion gallons annually) fromforeign sources than any other region along eastern North America and that this ballast water typically containstaxonomically diverse (e.g., clams, crabs, fish, worms) and abundant assemblages of living organisms. Currentstudies are examining: (l)key environmental conditions and biological traits that influence planktonics~rvivalduring transport; (2) the viability of larvae under a representative range of physical and chemical conditions uponarrival; and (3) the history and ecological impact-of invasions in Chesapeake Bay. Together, these projects willenhance our understanding of marine invasions and provide needed data for comparison with other aquatic

systems.

.L. David Smith,Smithsonian EnvironmentalResearchCentre, MarylandFax: +1-301-261-7954

.

lN fBe w s r e s

Snakes.

3-ll New Zealand?

The New Zealand Herald newspaper reported in January that Auckland Zoo is making a submission to Parliament inthe hope that snakes will be allowed into New Zealand -for educational purposes. Under current rules in the BiosecurityAct, all snakes are banned, and the zoo 's director Dr Richard Jakob-Hoff is reported as saying th-at this is not based ondetailed reasoning, but on irrational fear. He continues: "I am against the uqcontrolled import of snakes, but our maininterest in them is an educational one. And there are animals in zoos now that would be far more dangerous than somesnakes if they were to escape. There is plenty of overseas experience to draw on regarding the care and confinement ofsnakes".

Brown SnakeTree Feature

The New York Times Magazine of November 13, 1994 features an article on the bird-eating brown tree snake Boigairregularis, which has infested Guam and is now feared in Hawaii.

16

elsewhere in the world: they can nowattempt to persuade their fundingagencies that eradication of cats (ifproperly funded and followedthrough to the last animal) is feasi-ble.

Marion Islan.d is a South African sub,-Antarctic island in the southern In-dian Ocean. It has supported a mete-orological station since 1947. Fromthe early 1970s, the island has alsobeen the locale for research into thenatural (primarily bioLogical) sci-ences conducted as part of the SouthAfrican National Antarctic Pro-

gramme (SANAP).

Removingalien vertebrates from

subantarctic Marion

Island

Burrowing petrel breeding successhas increased markedly at MarionIsland post cats, making the eradi-cation programme a success story. Itis hoped that the petrel populationswill now recover to something liketheir former numbers, although thisis likely to be a slow process.

Marion Island did not escape the at-tention of sealers in the 19th Century.One undesirable consequence wasthe introduction of house mice'Musmusculus. Soon after the meteoro-logical base was built, mice becamepests wi~hin it, and domestic catsF elis catus were unwisely introducedto control them in 1949. The catsbred and the offspring soon becameferal, and by the 1970s were killinghundreds of thousands of burrowingpetrels a year.

John Cooper

Percy Fitzpatrick Institute of

African Ornithology

University of Cape Town

South Africa

E-mail: jcooper@botzoo.uct.ac.za

Recent research at Marion Island hassuggested that house mice are affect.ing the island's environment, prima-rily by reducing the soil invertebratepopulation, and that this may be ex-acerbated by global warming: likeelsewhere, Marion Island is warm-ing up. As a consequence, SANAPheld a two-day workshop in Pretoriain February 1995 to review the im-pact of mice on the terrestrial eco-system of Marion Island and to as-sess the desiragility and feasibilityof their eradication. The New Zea-land Department of Conservation'sexperience in eradicating rodents onislands will be most useful inassess-ing the feasibility of mouse eradica-tion on Marion Island. It is hoped thenext issue of the ISSG Newsletterwill be able to carry a summary re-port of the SANAP workshop.

.For recreational purposes, browntrout Salmo trutta were introducedinto a single stream on Marion Is-land in 1964, bringing the comple-ment of established alien vertebratesto three. Several attempts were madeto remove the trout in the 1980s byhand-netting at night with a spotlightand the last one was seen in 1984.

After much study in the 1970sand 1 980s,. an eradication programmeeventually led to the removal of allcats from the islandin199l; theirdemise being brought about by acombination of disease introduction,night-shooting,gin-trapping and poi-soning. The lesson seems to be: useas many techniques as possible anddo not give up until the last cat iskilled. Marion Island is the largestisland in the world, by far, fromwhich feral cats have been eradi-cated. This success is an encourag-ing force for managers of islands

Interested readers should contact meto be put in touch with the research-ers who have conducted work on in-troduced vertebrates at Marion Is-land and to obtain their publications.

7

wt ta a s a e rWith an estimated 3,000 species, on anyone day, offresh-water, brackish water (estuarine) and marine protists,animals, and plants in motion around the world in theballast of ocean-going ships, there is increasing globalinterest in exotic species invasions of aquatic environ-ments.

Ballast water invasion, known to biol()gists since the early1900s, have now in the 1990s entered the broader envi-ronmental awareness and conciousness of many govern-mental agencies, environmental organisations, and ship-ping and allied industries. Australia, New Zealand,Canada, the United States and other countries have ledextensive discussions at the Marine Environmental Pro-tection Committee of the United Nations' InternationalMaritime organisation over the last four years, leading toa draft proposal to include ballast water managementunder MARPOL guidelines. Independent and co-opera-tive research efforts on ballast water biology and man-agement are underway in 1995 in Australia, the U.S"Canada, Ireland, Scotiand, Germany, Sweden, Israel, la.,pan and other countries.

In only the last decade, many examples can be cited. TheJapanese seastar Asterias amurensis has appeared in Aus-tralia (where it has broad potential impacts on the shell-fish industry); the Japanese shore crab Hemigrapsussanguineus has colonisedAtlantic North America (whereit is now becoming relatively common from Cape Cod toChesapeake Bay); the American combjelly fishMnemiopsis leidyi has invaded the Black and Azov Seas(and been linked to the near-demise of regional anchovyfisheries); the Chinese estuarine clam Potamocorbulaamurensis has become one of the most abundant benthicorganisms in San Francisco Bay (where the disappear-ance of spring phytoplankton blooms in parts of the bay,and extensive decreases in zooplankton have been attrib-uted to high densities of this clam); the Indo-Pacific mus-sel Perna perna has colonised Caribbean mangrove eco-systems and Gulf of Mexico jetties (where, in both habi-tats, it forms extensive monoculture-like beds) and noveldinoflagellate blooms (some but not all linked to ballastwater releases) have appeared in many parts of the world.In the Great Lakes of Canada and the U.S. alone, threeEuropean fish, two species of zebra mussels, and a car-nivorous water flea, all unknown from North America in1980, are now six of the most common species regionallyor in large parts of those waters.

.

More than 50 different control and management strate-gies have been suggested to reduce or eliminate thenumber of species transported and released by ballastwater. Of these, one strategy, known as "ballast waterexchange", has floated to the top as an immediate stop-gap measure that has broad applicability. A vessel trans-porting ballast water from France to the harbour of Riode Janeiro, for example, would be requested under IMOguidelines (already issued in the form of voluntary ap-proaches to the problem) to deballast the French wateron the high seas (a procedure variously also referred toas open-ocean, deep-water, or mid-ocean exchange -allreferring to depths of greater than 2000 metres), and thenreballast.Estuarine or neritic organisms' would thus be released inmid-ocean, while the vessel would then release into Riode Janeiro marine organisms (such as oceanic

chaetognaths, copepods, globigerinids, radiolarians, andso forth) incapable of surviving in port waters.

Since the mid-1980s, scores of other invasions, rangingfrom amphipods and polychaetes to seasquirts andseaweeds, have been attributed to ballast water release,and it is widely acknowledged that even these are prob-ably a small fraction of the actual number of invasionsthat have occurred.

While this is a seemingly "simple" solution to ballast~

water-mediated invasions, many ships on many routes

may in fact not be able to exchange their water on the

high seas, relative to such factors as sea conditions andload configurations, or may be able to effect only partial

exchange. Thus long-term solutions are viewed as needed,

including the possibility of vessel redesign to permit

onboard ballast water treatment, using one or more avail-

able treatment technologies (thermal, chemical, UV

microfiltration, and dozens of other approaches) modi-

fied to vessel ballasting requirements (such as minimum

inflow and outflow velocities).

It appears that the number of invasions has in fact in-creased (rather than the increased number of reports be-ing due to increased awareness of the phenomenon), al-though the reasons for this increase remain a matter ofconsiderable discussion. While a number of hypothesesabound, a combination of more shipping, larger ships,cleaner waters, faster transit times, and new, or newlyintensified trade routes have all been implicated.

Q

transported species in Chesapeake Bay (see page 16), aswell as investigations on the history of invasions of thebay in general.

In September 1995, the International Council for the Ex ~

ploration of the Sea (ICES) is holding a special BallastWater Symposium during the ICES Annual Meeting inAarhus, Denmark.This symposium will bring together industry, government,and science viewpoints on the issue of ballast water in-vasions and the need to cpntrol ballast water releases ofexotic species. In the meantime, large-scale research ef-forts remain underway in the countries noted above. Theserange from monographic overviews and assessments ofballast water science, now or soon to be publish~d inCanada, Australia, and the US, to ship-sampling programsnow underway or planned in a number of countries, toextensive experimental laboratory investigations.

Marine invasion biologists predict that the remainder ofthe 1990s will be marked by a series of new invasionsglobally, akin to the remarkable phenomena now beingobserved in soutern Australia, San Francisco Bay, theBlack Sea, the Caribbean-Gulf of Mexico, and other shal-low water ecosystems.Rapidly growing attention to coastal, transoceanic andinternational movement of ballast water -and to othermechanisms of human-mediatedtransport of aquatic or-ganisms -may lead to fewer invasions by the start of the2lst century.

An example of the latter are studies now in progress atthe Smithsonian Environmental Research Centre (SERC)in Edgewater Maryland, where an invasions researchgroup has research programs in place on the post-trans-port viability and colonisation potential ofballast-water-

James T. Carlton, Williams College, Mystic Seaport, CT06355 USA and Gregory Ruiz, David Smith and AnsonNines, SERC, Edgwateri MD, USA.F ax: + 1-203-572-5329

--+-

.Garden Slugs Milax gagates

Introduced slugs have become widespread in Hawaii aridmay pose a major, but little-recognized, threat to nativeplant species. Common garden slugs, Mi/ax gagates, havebeen noted on greenswordArgyroxiphium grayanum in aremote rainforest area of East Maui. Slug damage hasbeen observed on several rare plant species includingRanunculus mauiensis, on several lobelioids, and bnSchiedea haleakalensis.Lloyd Loope. Fax: +1-808-572-1304

This plant can grow as tall as 25 metres, smothers anyundergrowth (causing concern for future soil erosion, dueto a lack of stabilising roots) and sprouts vigorously. It issurprisingly re~istant to chemicals.John Healey, Univ~rsity ofBangor in Wales.Phone: +44-1248-351151

"Wild Coffee" Pittosporum undulatum

This invader (which is totally unrelated 10 coffee) wasimported to Jamaica from Australia in the l880s tobrighten up the Cinchona Botanical Garden, and is nowfound throughout the Blue Mountains National Park. Atrisk today are 200 species of tree that can be found onlyin Jamaica, and the rich variety of rare and endemic birdsthey support. Wild coffee seedlings already make up 99per cent of some monitored plots;

Tropical Soda Apple Solanum viarum

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Tropical soda apple is a prickly perennial plant native toBrazil, that was first documented in Florida in 1988. Itgrows between latitudes 37° south and north. By 1994 itwas estimated to occur on at least 40,000 acres of im-proved pastures and 30,000 acres of pinelands in Florida.It forms impenetrable stands, threatening biodiversity.Wild deer and raccoons are, the main vectors of the plantinto natural areas.Randy Westbrooks, Whiteville Methods Plant Centre.Fax: +1-910-648-4770

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JProle

At present no readily-accessible database of weeds and invasive plants exists.This six-month project aims to recommend a format and structure for a database oftropical and subtropical weeds and species with invasive potential, to possibly pro-duce a prototype database and also to recommend channels of dissemination toallow its widespread use.The work is based at the Oxford Forestry Institute within the University of Oxford,and is designed to support the Global Change and Terrestrial Ecosystems (GCTE)initiative. It involves an extensive review of the current status of r,esearch in thisfield, and in particular an investigation into the possible existence of similardatabases in other countries worldwide.Contact is being made with any researchers who have an interest in such plants andin particular anyone who might have compiled a database on a group of weeds orinvasive plants. As the range of end-users could possibly be very wide, the opin-ions of anyone who might need to access any type of information on weeds orinvasive plants in the future is being sought, so that a user-friendly database iscreated at the outset. Though this is currently a short-term project, it is hoped thatfurther funding or collaboration will see it continued. Any vIews or informationwould be much appreciated. -<fT

Hugh FrostDepartment of Plant Sciences, University of Oxford, UKfax: +44-1856-275146E-mail: hughfrost@plant-sciences .oxford.ac .uk

Information on non-native marine species found in British waters has been col-lated at the UK's Joint Nature Conservation Committee. Details of dates, methods,origins and routes of introduction have been collected together with appraisals ofthe reasons for success of non-native species, their current distribution and rates ofspread. The effects of introductions on the environment and commercial interestsas well as an assessment of the effectiveness of control mechanisms employedhave also been made. This information has been put together for 'Over 40 speciesidentified as being established, self-sustaining and non-indigenous to Britishwa-ters. A report of the study evaluating the British situation in an international con-text is currently being compiled by:

Clare Eno, Marine Conservation Branch, JNCC, UK

Fax: +44-733-555948

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An overview of the impact of salmonid fish on the native freshwater andestuarine fauna of Australia is about to start on behalf of the Australian NatureConservation Agency. This work will be carried out by Phil Cadwallader, andis hoped to be complete by mid 1995.

Phil Cadwallader, AustraliaPhone: +61-57-742057

Researchers at the University of Glasgow Field Station are studying the ef-fects of introduction of five new species of fish into Loch Lomond, Scot.land's largest freshwater lake, since 1980. These species have changed a com-munity that had remained stable in composition for two centuries. The twomost successful species are the dace Leuciscus leuciscus and the ruffeGymnocephalus cernuus. The best documented effects include diet shiftsamongst top predators in the community (pikes, herons and cormorants haveall switched their diet to feed upon abundant introduced species) and the di-rect predation by ruffe on the eggs of a rare fish species Coregonus lavaretus,found in only one other loch in Scotland.-+Submitted by Michael Usher.Contact: Colin Adams, University Field Station, GlasgowFax: +44-36-087381

The first phase of research on Australia's cane toads. funded by the FederalGovernment through the CSIRO Division of Wildlife and Ecology. was com-pleted early in 1994. A number 6f new projects are now under way. mostimportantly. the setting up of a research group based at the CSIRO AnimalHealth Laboratories at Geelong. Victoria. which will assess the pathogenicityand specificity of viral isolates against toads. The search for further virusesand microbes will be extended to other parts of the world where Bufonidtoads exist naturally. Several new projects are designed to assess the impactof toads on native fauna and determine the benefits that might flow from thedevelopment of a successful bio-control programme. A joint working grouphas been established to consider the problems associated with the natural andassisted spread of toads in the Northern Territory.

Contact: Alex Hyatt, Brian Green, Tony Robinson, at Geelong.Fax: +61-52-27-5555

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The flightless AldtlbFlIn rail, Dryolimnas cuvieri, is!hreated by goatdamage to its native atollc

.The impacts of invasive spe-cies on birds are well known to ushere in New Zealand. The ecologi-calperils of living on an island havebeen too great for many of our an-cient endemics, and they have suc-cumbed to the ravages of introduced

rodents, mustelids, marsupials andunguliltes. Today, most of the NewZealand effort towards the recoveryof threatened birds is aimed at con-trolling or eradicating invasive spe-cies; removing birds to safe havensor, in some audacious examples, try-ing to teach birds to deal better withthe threats which invaders pose.

the arrival of the brown tree snakeon Guam. have meant the loss of sev-eral bird species. For animals gener-ally, around 39% of extinctions ofknown cause are attributed to intro-duced species. For birds, some 54%of species lost sincel600 (wherecause is known) fell victim to intro-duced predators. competitors or dis-ease, and 17% of globally threatenedspecies are currently at risk from in-troduced species. Birdlife Interna-tional attributes difficulty in address-ingthe problem to obstacles such aslack of information and policy. In-vasion is still poorly understood at"wcal, national and internationallev-els. For example. there is no readilyaccessible database of species knownto have caused problems (somethingwhich IUCN is in a good position to

tackle). Secondly, most countrieshave weak policy or legislation forconsideration of possible ecologicaleffects of alien introductions. Quar-

Of course, the problems of invadersare not just restricted to this comerof the planet: they occur worldwide.However, recognition of the the scaleof the problem and consequent ef -fort in dealing with it is only nowgrowing. But work to protect globalbiological diversity is still dominated

by the imperative to protect land,while a leading cause of loss goesrelatively unaddressed. Perhaps thecontinental perspective dominatesthe scene and causes island problemsto remain in relative obscurity.One organisation with a global view,Birdlife International (formerly theInternational Council for Bird Pres-ervation), has a history of involve-ment on islands such as the Sey-chelles and Mauritius, andlatterly inNew Caledonia. At their 21st WorldConference, held in Rosenheim,Gennany, in August 1994, there wasconsiderable. discussion of the prob-lems of invasive species and theireffects on birds and other elementson exotic introductions.The policy paper reviewed the scaleof the problem. For example, mostcountries have seen the introductionof between 100 andIO,OOO exoticspecies. Many are not truly invasivebut some single introductions, like

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antine or biosecurity protocols, if established, are often not enforced.Thirdly, some of the problems are, or are perceived as, so intractable that addressing them is not an economically viable

option.The draft policy promotes several types of action. Firstly, the development of ecological restoration through the controlor eradication of introduced species needs to be fostered in tandem with new techniques. There must also be a focus onecological prophylaxis -on preventing introductions -and on mitigation when they occur. The Convention on Biologi-cal Diversity is an important facilitatory tool for promotion of appropriate national policies.There is also a need for two databases: one a comprehensive globallistofinvasive species and invasions -an importantaid in advocacy; the second a more complete record of the status of ecosystems, habitats, islands and countries withrespect to invasive species. Such a review would be a key tool for invasion prevention or restoration planning.

The in-country Partners of Birdlife are asked to analyse their own Government policies and legislation on the issue.They are also encouraged to develop or promote model restoration projects based on the control or eradication of someinvasive species. The Birdlife Secretariat is asked to facilitate this work by helping to establish the databases andhelping promote the relevant policy tools and model projects.

Rod HayNew Zealand Department of Conservation, AucklandFAX: +64-9-377-2919

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This first issue of Aliens has been produced with a small grant from IUCN. We wish to continue publication of thisnewsletter, however further work depends on the support we receive from both individuals and sponsors,We seek a main sponsor (please contact Mick Clout at the address below) to cover the production costs of Aliens -

which will hopefully appear biannually -but your individual donations are the vote of confidence, which will help usattract sponsors.We are therefore asking for your financial support; Please use the tear-off slip to send donations to the address below.Further copies of this and future newsletters can be obtained for US$1 0.

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I wish to make a donation to the Invasive Species Specialist Group of

US$IO. US$25.. US$50. US$100.., ...US$500 Other.

Please make cheques out to the "IUCN Invasive Species Specialist Group" and send to the follow~ing address:

c/o Mick Clout, Centre for Conservation Biology,School of Environmental and Marine Sciences, University of Auckland (Tamaki Campus)~Private Bag 92019,Auckland, New Zealand.

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M o de 1 L e gis lationIn 1993 the US Congress recognized process of revising the sketch to pro-the need for greater understanding of duce a rriore refmed model act, whichthe problem of harm by non-indig- tries to answer four basic questions:enous species in the US when it di-rected the Office of Technology As-sessmentto evaluate, and report on,the topic.

to be effective it must do more thanthat. The group is working to makethe legislation as simple and clear aspossible, with the minimal creationof new bureaucracies. For example,the draft act is likely to propose theminimum necessary number of cat-egories for identifying the known orpotential risk of a proposed introduc-tion, and a specific number of re-

sponse categories.

That body produced a superb report,titled "Harmful Non-Indigenous.Species in the United States", andfound that approximately 4500 spe-cies in the US were non-indigenous;and 200 of those were introduced inthe last decade. Such new awarenesssuggests the time is ripe for consid-eration of harmful non-indigenousspecies and development of wise

policies.

The goal of the AGCI group is toproduce a draft law which can serveas a -model to be amended to fit theneeds of different localities, states,nations and international concerns.We also hope that the promulgationof a Model Act on the Prevention ofHarm By Non-Indigenous Specieswill continue the trend towardSgreater recognition of the extensiveharms already caused by such intro-ductions.

* First, what government or non-

government e:ntity has responsibilityfor identifying non-indigenous spe-cies invasions, where is informationon the nature and scope of invasionscollected, and who has access to thisinformation, and in what form?* Second, what government or non-

government entity has responsibilityfor responding to invasions by harm.;ful non-indigenous species, and whatkinds of responses are encouraged orallowed? Also, who should fund re-sponses to particular invasions?* Third, what processes and stand-

ards are used to assess prQPosed in-tentional introductions of non- indig -

enous species, including new agri-cultural and horticultural products,and biological pest controls?* Fourth, what kind of follow-up is

conducted after efforts to respond toinvasions, or following intentional orunintentional introductions, to assessand understand the actual impact ofnon-indigenous species on other spe-cies, on ecosystems, and on ind~s-

try?

From August 17 to September 31994, an inter-disciplinary group metunder the auspices of the Aspen Glo-bal Change Institute (AGCI} to con-sider "biological invasions as a kindof global change" (see Aspen Meet-

ing report, page 5).

-tFor further infonnation, or to providesuggestions for the model act, con-tact:One of the products of the AGCI

conference was a sketch for a modelact to reduce both the rate of intro-ductions and the harm from bothcurrent and future introductions ofnon-indigenous species. The Aspengroup is currently engaged in the

A good law will respond to each ofthe four questions listed above.. But

Marc L. MillerEmory University School af LawAtlanta, Georgia, USAFax: (404) 727-6951.E-mail: mmiller@law.emoly.edu

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Aliens is edited anddesktop-published using PageMaker 5, by Sarah Lowe, and printed onCyclus lOO gsm 100% recycled paper processed entirely from post-consumer waste withoutthe use of any chlotine-bleaching process.

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