Conservation and Management of Mangroves in Uttara Kannada

Sahyadri Conservation Series 20

Conservation and Management of Mangroves

in Uttara Kannada, Central Western Ghats

Subash Chandran M.D Ramachandra T.V. Joshi N.V.

Prakash N. Mesta Bharath Settur Vishnu D. Mukri

Karnataka Forest Department, Honavar Forest Division

Western Ghats Task Force, Government of Karnataka

Karnataka Biodiversity Board, Government of Karnataka

The Ministry of Science and Technology, Government of India

The Ministry of Environment and Forests, Government of India

ENVIS Technical Report: 50 November 2012

Environmental Information System [ENVIS] Centre for Ecological Sciences,

Indian Institute of Science, Bangalore - 560012, INDIA

Web: http://ces.iisc.ernet.in/energy/ http://ces.iisc.ernet.in/biodiversity Email: [email protected],

[email protected]

Sahyadri Conservation Series 20 ��

Conservation and Management of Mangroves in

Uttara Kannada, Central Western Ghats

Subash Chandran M.D Ramachandra T.V. Joshi N.V.

Prakash N. Mesta Bharath Settur Vishnu D. Mukri

Karnataka Forest Department, Honavar Forest Division

Western Ghats Task Force, Government of Karnataka

Karnataka Biodiversity Board, Government of Karnataka

The Ministry of Science and Technology, Government of India

The Ministry of Environment and Forests, Government of India

ENVIS Technical Report: 50

November 2012

Environmental Information System [ENVIS] Centre for Ecological Sciences,

Indian Institute of Science, Bangalore - 560012, INDIA Web: http://ces.iisc.ernet.in/hpg/envis

http://ces.iisc.ernet.in/energy/ http://ces.iisc.ernet.in/biodiversity

Email: [email protected], [email protected] [email protected]

Mangroves of Uttara Kannada district 2012

i


Uttara Kannada district, Central Western Ghats

C O N T E N T S

PAGE NO.

Contents i

Executive Summary iv

CHAPTER 1. INTRODUCTION 1

Importance of Mangroves 2

Mangroves – Global scenario 11

Distribution of Mangroves in India 12

Mangrove Scenario in Karnataka 14

Mangrove Scenario in Uttara Kannada District

15

Forest Administration 17

Methods adopted 18

CHAPTER 2. IDENTIFICATION OF MANGROVES

19

I. True mangroves 19

II. Mangrove associates 23

CHAPTER 3. MAGROVES OF HONAVAR FOREST DIVISION

30

3.1 ADMINISTRATIVE JURISDICTION FOR MANGROVES

30

Introduction 32

Honavar Forest Division: Salient Features 32

Mangrove area distribution and suitable areas for planting

32


ii

3.2 ESTUARY-WISE MANGROVE SITUATION IN HONAVAR FOREST DIVISION

39

Estuary and creek-wise mangrove areas and potential areas

39

Mangroves in relation to salinity 41

A. MANGROVES OF GANGAVALI ESTUARY

41

Waterscape/landscape elements 42

Mangroves and potential mangrove areas: village-wise distribution

42

Mangrove associates 50

Some notable mangrove localities 50

Remote sensing applications 52

B. MANGROVES OF AGHANASHINI ESTUARY

55

Introduction 56

Mangrove areas and potential areas for planting

56

Site-wise presence of mangroves and associates

59

Notable localities studied for mangroves 61

Applications remote sensing for mangrove studies in Aghnashini

65

C. MANGROVES OF SHARAVATHI -BADGANI ESTUARINE COMPLEX

69

Salinity decline in Sharavathi 70

Details of mangroves and associates: site-wise

71

Locality-wise details: Sharavathi 72

Factors affecting mangrove community 74

Badgani estuary 74

Remote sensing for mangrove species/land cover-land-use prospecting

75


iii

D. MANGROVES OF VENKTAPUR RIVER 78

E. ALVEKODI CREEK 84

3.3 MANGROVE SITUATION: RANGEWISE

86

Mangroves of Bhatkal forest range 86

Mangroves of Manki Range 89

Mangroves of Honavar Range 92

Mangroves of Kumta Forest Range 97

Mangroves of Katgal Forest Range 100

Mangroves of Hiregutti Forest Range 102

ANNEXURE-I Location and Area (ha) of mangrove patches in Bhatkal Range

106

ANNEXURE-II Location and Area (ha) of mangrove patches in Manki Range

112

ANNEXURE-III Location and Area (ha) of mangrove patches in Honavar Range

113

ANNEXURE-IV Location and Area (ha) of mangrove patches in Kumta Range

125

ANNEXURE-V Location and Area (ha) of mangrove patches in Katgal Range

137

ANNEXURE-VI Location and Area (ha) of mangrove patches in Hiregutti Range

141

ANNEXURE-VII Availability of potential Area (ha) for Mangrove planting in Bhatkal Range

148

ANNEXURE-VIII Availability of potential Area (ha) for Mangrove planting in Manki Range

149

ANNEXURE-IX Availability of potential Area (ha) for Mangrove planting in Honavar Range

150

ANNEXURE-X Availability of potential Area (ha) for Mangrove planting in Kumta Range

154

ANNEXURE-XI

Availability of potential Area (ha) for Mangrove planting in Katgal Range

156

ANNEXURE-XII Availability of potential Area (ha) for Mangrove planting in Hiregutti Range

157

REFERENCES 158


iv


Uttara Kannada district, Central Western Ghats

EXECUTIVE SUMMARY

The mangroves constitute a community of usually woody, evergreen, salt tolerant plants of soft

and swampy mud of tropical sub-tropical coastal zones preferring river mouths, lagoons and

creeks. Mostly found in intertidal zones and stagnant swampy coastal waters they have special

adaptations like physiological and structural mechanisms to combat excessive salt in the

medium, special aerial root systems for support in unstable slushy substratum and for gaseous

exchange as they are anchored in anoxic water-logged conditions. Some, especially members of

Rhizophoraceae have their seeds germinating into seedlings while the fruits are still attached to

parent plant. These juvenile seedlings fall vertically into the mud, get stuck there and develop

into new plants.

Till about 1960s, mangroves were largely viewed as “economically unproductive areas” and

were cut down for meeting a variety of human needs and the swamps reclaimed for human

habitations. Mangrove areas today rated among the most productive ecosystems on this planet.

They generate nutritionally important detritus for fishes, prawns, crabs, oysters etc. and shelter

estuarine and marine organisms and provide safe breeding grounds for many, as well as provide

home for numerous kinds of birds.

Mangroves play important role in ecosystem functioning and are of great economic importance

for fisheries. Detritus is also transported a food by tides to near-shore organisms. Mangroves

contribute to the stabilization of the shoreline and prevention of shore erosion. They serve as a

barrier against storms so as to lessen damage to coastal land and residents. The dense network of

supporting roots and breathing roots give mechanical support to the tree and trap the sediments.

Without mangroves, all silt will be carried into the sea, where turbid water might cause corals to

die. Mangrove trees act as sinks, which concentrate pollutants such as sewage, toxic minerals,

pesticide, herbicides, etc. They sequester much more carbon per unit area than even tropical rain

forests. Wherever mangroves are rich livelihood opportunities for humans are great, including

promotion of tourism.

Among the various direct uses of mangrove products are edible fruits and fronds, honey,

medicine, timber, fuel wood, manure, tannin, bio chemicals, paper-pulp, genes for salt tolerance

in crop plants, dyes, bio-fuel for blending with petroleum, fibre, perfume, fish feed etc.

By far tropical Asian countries account for highest area under mangroves. The Sunderbans, along

the shores of West Bengal and Bangladesh have the richest and largest mangrove community in


v

the world. Andaman and Nicobar Islands, Orissa, estuaries of Andhra Tamil Nadu and Gujarat

have large areas of mangroves.

Mangrove vegetation was neglected totally in Karnataka State and national level surveys hitherto

showed no mangroves or only negligible areas under it (just 1 or 2 sq.km), which is far from the

reality. As mangroves are inevitable for integrity of estuarine ecosystems and maintaining their

high productivity a detailed micro level survey was found to be necessary in every and estuary

and creek.

Karnataka estuarine regions are densely populated by humans because of high productivity and

transportation facilities that these areas provided in continuity with the Arabian Sea. Bulk of the

shallow water coastal swamps areas were presumably cleared for growing salt tolerant rice in

reclaimed fields protected from salt water entry by making embankments. Traditionally the

farmers planted mangrove trees alongside these bunds. Later when stone bunds were built by the

Government, mangroves were cut down in large scale.

The start of Linganmakki dam for power generation in the Sharavathi River would have caused

obvious decline in estuarine salinity on account of continuous release of fresh water affecting

adversely estuarine ecosystem, particularly mangroves. Such changes went practically

unrecorded in science. The arrival of one more dam at Gersoppa in the same river caused still

further dilution so much so most of the time estuarine salinity is in near fresh water conditions.

The mangrove diversity declined as a consequence leaving behind very few species, especially

the tree Sonneratia caseolaris, tolerant of nearly fresh water conditions.

Recent decades witnessed spurt of shrimp farming activities in specially prepared shrimp ponds

from which every trace of mangroves were removed.

At present there is increased awareness on the importance of mangroves. Under various schemes

sponsored by State and Central Governments mangrove plantings have been made in the

estuaries of Karnataka. The Honavar Forest Division achieved spectacular progress in mangrove

afforestation, especially in Aghanashini estuary and Kumta creek. Increased area under

mangroves is bound to have beneficial effects on estuarine productivity and biodiversity as well

as causing increased nutrient flow into the Arabian Sea itself.

In spite of such progress, in the absence of overall evaluation and mapping of the mangrove

situation it has become difficult to take up the cause for further afforestation of Karnataka’s

estuaries with mangroves. As evaluation requires mapping of existing mangroves and depiction

of suitable areas for further planting a detailed estuary and creek-wise survey is found necessary.

Moreover estuaries need to be demarcated into different salinity zones for making appropriate

combination of species for planting in high, medium and low salinity zones. The current study

was carried out at the behest of Honavar Forest Division of Kanara Forest Circle.


vi

Of the methods used for the survey were all out field studies, physically visiting all the estuaries

and creeks and noting down mangrove species present in different patches through sampling, and

finding out the geo-locations by using GPS. Google imageries have been very useful in locating

mangrove patches and in estimating the potential intertidal areas for future planting. Counts of

trees were made in selected locations to find out percentage composition of species. Salinity

levels were noted down to classify mangroves into high, medium and low salinity species.

Remote sensing imageries had only limited applications for identifying mangrove trees on the

substratum, but nevertheless estimates were done of the area under frequently occurring tree

mangroves. RS data of 1989, 2000, 2003 and 2010 helped in finding out changes in land use land

cover in the estuaries, including one km buffer zone outside.

Honavar Division has four estuaries towards the river mouths of Aghanashini, Sharavathi,

Venktapur and part of Gangavali. The Badgani River merges with the Sharavathi estuary towards

its mouth. All the estuaries have normal rise and fall of marine tides and normal ranges of

salinity expected of local estuaries except the Sharavathi estuary which has minimal salinity

(<0.5 ppt) most of the time due to constant release of fresh water from hydro-electric projects

from upstream areas. This has caused major decline in mangrove diversity as high salinity

mangroves have totally vanished and medium salinity ones turned minimal and low salinity ones,

mainly Sonneratia caseolaris favoured.

A detailed distribution map of Honavar Forest Division will be help in assessing range-wise,

section-wise and beat-wise and estuary and creek-wise mapping of mangroves. This is expected

to facilitate more efficient management of mangroves. The mapping also covered mangrove

associates. The true mangroves (confined to estuaries and creeks) of Honavar Division belong to

6 families, 8 genera and 11 species. If we exclude the exclusive estuarine grass Porteresia

coarctata the species number will decline to 10. In addition, a fern, Acrostichum aureum also

occurs in mangrove habitats of less brackish habitats. Rhizophoraceae members Rhizophora

mucronata, R. apiculata, Kandelia kandel and Bruguiera gymnorrhiza are typical mangroves

with stilt roots and viviparous seeds. Bruguiera occurs nowhere except sparingly in Venktapur

estuary.

The study covered also about 32 species of notable mangrove associate species which have also

distribution beyond the mangrove areas in the lands away from estuaries.

Mangroves of the estuaries and creeks are in high state of fragmentation due to high degree of

human impacts through centuries, which include reclamation of estuaries for rice and coconut

cultivation, expansion of human settlements, shrimp farming, salt production, shell and sand

mining, cutting for fuel and minor timber etc. Altogether 1549 patches were recognized in the

Forest Division. These also include linear patches along the borders of estuaries.

We have estimated 391 ha of mangrove areas and 1019 ha suitable for planting. If we consider

rangewise mangrove area highest (128 ha) is in Honavar Range, followed by Hiregutti Range (88


vii

ha) and the least occurs in Manki Range (4 ha). Manki also does not have any area for mangrove

planting. Hiregutti Range also has largest area (708 ha) suitable for mangrove planting. Honavar

Range has 161 ha for mangrove planting while Kumta has 91 ha. In Chapter 3 (section 3.1) is

provided all the details regarding administrative unitwise (range, section and beat) area under

mangroves and suitable areas for planting.

In Chapter 3 (section 3.2) estuary-wise and creekwise mangrove area and potential area for

planting are given. Area under mangroves is highest (169 ha) in Aghanashini estuary, followed

by Sharavathi-Badgani (136 ha) and Gangavali (46 ha). Considering estuary-wise suitable area

for mangrove planting Aghanashini has highest (711 ha), followed by Sharavathi-Badgani (184

ha), Gangavali (95 ha) and Kumta creek (42 ha). Even the smallest creeks of less than 1 ha are

considered in this study.

Whereas Rhizophora apiculata and Avicennia marina are high salinity mangroves (>15 ppt.),

Aegiceras corniculatum prefers medium salinity zones (5-15 ppt). Rhizophora mucronata,

Avicennia officinalis, Sonneratia alba, Kandelia kandel and Excoecaria agallocha are seen in

high and medium salinity zones. Acanthus ilicifolius occurs in all salinity zones, but Sonneratia

caseolaris has presence in medium to very low salinity (< 0.5 ppt) conditions. Estuarywise and

villagewise details of mangrove species present are given in Chapter 3 (section 3.2).

During mangrove afforestation in the estuaries care should be taken to avoid planting in bivalve

and oyster beds which are highly productive of food for humans and animals, including several

species of birds.

Rangewise and beat wise mangrove areas and potential areas for planting are shown in maps for

the convenience of forest department staff involved in mangrove protection and planting

(Chapter 3, Section 3.3). The annexures contain very detailed information on sectionwise and

beat area under mangroves and suitable areas for planting.


viii

RECOMMENDATIONS

The exercise carried out in minute details could be of great help to the Forest Department in

mangrove management. Mangroves are classified under CRZ-I area and therefore mangrove

maps could be used for delineating CRZ I areas.

It is recommended that similar exercises be carried out in other

estuaries of Karnataka as well, considering the tremendous

ecological and economic uses of mangroves

As Rhizophora mucronata is the main species used for mangrove

afforestation, such monoculturing has to be avoided in future

giving way to fair mixing of other species. More importance

should be given to Avicennia spp. and Sonneratia spp.

The rare population of Bruguiera gymnorrhiza in Venktapur

estuary should be protected and more number of seedlings should

be introduced here from Kali or Kundapur estuaries, as local

regeneration is poor.

Many aquaculture ponds are abandoned due to losses suffered by

shrimp farmers. They are also unfit for rice cultivation.

Government may formulate a scheme to acquire such areas for

planting with mangroves.

Honey production in mangrove areas is a totally neglected

economic activity in Honavar Division as well as in the entire

coastal Karnataka. As mangrove honey with rare mix of salts can

have greater value bee keeping experiments should be carried out

in the estuarine areas.

Mangrove based tourism for bird watching and for scenic

enjoyment should be promoted as a good income generating

activity for the local VFCs (Village Forest Committees).

Appropriate training for local youth in arranging such mangrove

tours will provide newer livelihood opportunites.

Mangroves of Uttara Kannada 2012

1

1.0 INTRODUCTION Mangroves are a group of plants that occur in the coastal intertidal zones of tropics and the sub-

tropics. The mangrove community as a whole consists of salt tolerant plants of soft and swampy

mud, mostly trees and shrubs, with broad, leathery, evergreen leaves. In some trees roots from

the main stem and branches grow vertically down and provide additional support like stilts in an

unstable, slippery substratum. In many others roots protrude into the air like sticks, knobs or

loops, or creep in serpentine manner all around the tree, exposed fully during the low tide. These

roots are meant for taking in air for respiration, as the water-logged soil is deficient in oxygen. In

some trees the seeds germinate while the fruits are still attached to the plant, and green seedlings

of varied lengths hang from the parent plants until they achieve appropriate length, specific to the

species, drop vertically down into the soft mud. Soon they develop the root system and become

independent plants. This nature of certain mangroves to ‘give birth’ to live seedlings instead of

shedding their fruits or seeds is known as vivipary (Woodroffe, 1987; Blasco et al., 1996; Duke

et al., 1998). The term mangroves refer to an ecological group of halophytic plant species which

is known as the salt tolerant forest ecosystem and provides a wide range of ecological and

economic products and services, and also supports a variety of other coastal and marine

ecosystems. Mangroves occupy less than 1% of the world’s surface (Saenger et.al, 1983) and are

mainly found between the Tropic of Cancer and the Tropic of Capricorn on all continents

covering an estimated 75 percent of the tropical coastline worldwide.

Mangroves make special type of vegetation that exists at the boundary of two environments

using a variety of survival and reproductive strategies. Till about 1960s, mangroves were largely

viewed as “economically unproductive areas” and were therefore destroyed for reclaiming land

for various economic activities. Gradually, however, the economic and ecological advantages of

mangroves have become visible and their importance is appreciated. Every ecosystem supports

human life by giving direct or indirect benefits and services. Mangrove areas today rated among

the most productive ecosystems on this planet (Odum 1971).

Mangroves constitute one of the important parts of an estuarine ecosystem and in fact form an

icon for the estuarine ecosystem. A layer of earth or sand, usually deposited by rivers and flood

tides and shore free of strong wave and tidal action promotes extensive development of

mangroves. They also require salt and brackish water. Mangroves are best developed on tropical

shorelines where there are large areas available between high and low tide points. Large

mangrove formations are typically found in sheltered muddy shorelines that are often associated

with the formation of deltas at the mouth of a riverine system. Mangroves can also be found

growing on sandy and rocky shores, coral reefs and oceanic islands. There are instances where

islands can be completely covered by mangroves. It is impossible to describe a typical mangrove,

as the variation in height and girth, even for the same species, is immense, depending on the

many factors that control growth.


2

Importance of Mangroves: Mangroves forests, in their well developed state, constitute one of

the most productive features of coastal ecosystems across tropical and subtropical regions of the

world. By generating nutritionally important detritus, used by fishes, prawns, crabs, oysters etc.

for reproduction and growth and by sheltering of various kinds of animals such as fish,

crustaceans, birds, reptiles, and mammals mangroves play an important role in the ecosystem

functioning and are considered of great economic importance for capture and captive fisheries.

Detritus is also transported, distributed and consumed as food by various detritivorous estuarine

and near-shore organisms. A rich biodiversity is observed in the mangroves with plants and

animals, which are irreplicable, and forms a good genetic treasure house. Mangrove wetlands are

a multiple use ecosystem that provides protective, productive and economic benefits to coastal

communities. Mangroves contribute to the stabilization of the shoreline and prevention of shore

erosion. They serve as a barrier against storms so as to lessen damage to coastal land and

residents. The dense network of supporting roots and breathing roots give mechanical support to

the tree and trap the sediments. Without mangroves, all silt will be carried into the sea, where

turbid water might cause corals to die. Mangrove trees act as sinks, which concentrate pollutants

such as sewage, toxic minerals, pesticide, herbicides, etc. (FAO, 1982; Saenger et al., 1983;

Hamilton and Snedaker, 1984; Alongi, 2002).

The mangrove ecosystems are associated with rich diversity of organisms and are also the

nursery and breeding ground of several marine fauna like prawns, crabs, fishes and molluscs.

They enhance the fishery production of nearby coastal waters by storing nutrients and detritus.

Through shedding of their leaves mangroves tend to remove salt accumulated in them. However,

most land plants, except the halophytes, are incapable of such tolerance to salty environments.

The shed leaves of mangroves turn into detritus, which is colonized by fungi and bacteria and

this detritus turn into a valuable pool of nutrients. This detritus is consumed by variety of

bivalves, shrimps and fishes, many of which migrate into the mangrove areas for better feeding

and protection. Birds are a prominent part of most mangrove forests and they are often present in

large numbers. Almost 120 birds are found in the Aghanashini estuary of Kumta taluk in the

Honavar Forest Division. They use mangrove environs as breeding and feeding grounds. The

Royal Bengal Tiger is one of the unique resident species of mangroves of the Sunderbans.

Mangroves sustain the ecological security of the coastal areas as well as livelihood security of

the thousands of fishing people of estuarine and coastal villages. Nevertheless, because

mangroves grow where nothing else grows, they are always useful, even where they cannot be

managed as productive forests. The enrichment of brackish and coastal waters provided by the

mangrove vegetation may be substantial and should not be overlooked.

Good mangrove vegetation is an excellent indicator of the health of coastal ecosystems.

Mangrove ecosystem traps and cycles various organic materials, chemical elements and


3

important nutrients. The roots provide attachment surfaces for many organisms. Many of these

attached animals filter water through their bodies and, in turn, trap and cycle nutrients.

Mangroves provide protected nursery areas for fishes, prawns, crabs and shellfish. They provide

food for multitudes of marine and estuarine animals, such as various fishes and prawns of diverse

species, oysters etc. Many animals find shelter amidst the network of roots, where fisherman

cannot cast his nest nor the boatman ferry through it. The general importance of mangroves at

many levels is provided in Table 1.1

Table-1.1: The general uses of mangroves and mangrove associates Ecological uses Economical uses Social uses

Erosion control Fishing Education

Protection from damage Shrimp and crab industries Ecotourism

Indicator of climate change Charcoal production Food

Habitat provision Timber production Local employment

Water quality management Firewood Agriculture

Carbon Sequestration Traditional medicine

Mangroves for food security: Many nurture the misconception that mangroves are dreaded and

disease causing impenetrable swamps and they need to be cleared and reclaimed for the sake of

public health. In fact the value of mangroves as storehouses of food, directly in the form of

edible mangrove products and honey and indirectly in the form of enhanced fishery resources, is

more known to the inhabitants of estuarine villages. Today, there is rising global awareness on

the importance of mangroves. Crabs, clams, oysters, fish and other food are often collected there.

Mangrove trees grow well in their special conditions, and, like the tropical forest, produce a lot

of leaves and other organic matter. The leaves fall in the water, where they disintegrate due to

fungal and microbial action. This detritus becomes food for shrimps, crabs, oysters, shellfishes

and so on, which are of immense importance in human subsistence and commerce. An entire

detritus based food web of the coastal wetlands is mainly based on mangroves. This rich food is

not only eaten in the mangrove swamp, but much of it may be carried out into the lagoon or to

coral reefs and other coastal fisheries areas, where it helps to feed the fish. The areas near

mangroves are thus often very important for fishing.

A positive correlation between mangrove area and near-shore fish and shrimp catches was

reported demonstrated in the Philippines, Malaysia, Indonesia and Australia. Mangrove swamps

are critical nursery grounds and refugia from predation for commercially important shrimps of

Penaeus spp. and spiny lobster (Panulirus argus). It has been estimated that 60% of the

commercial catch in Fiji depends on mangroves (Hamilton & Snedaker, 1984). In the Matang

mangrove swamp of Malaysia the contribution of mangrove carbon to prawn tissues was as high


4

as 84% in the swamp. It decreased in the offshore direction, where the contribution of

phytoplankton became more important (Chong et al., 2001)

The study by Boominathan et al (2008) estimated that about 22,000 tons/year of edible bivalves,

worth Rs.66 crore at current market prices, were collected from the Aghanashini estuary alone in

the Honavar Forest Division. These bivalves are detritus feeders and obviously vegetation

resides, including from mangroves, feed them and also many fishes, crabs, crustaceans etc. The

shell deposits of these bivalves worth several millions of rupees are mined out annually from the

same estuary. This is apart from the rich fisheries that the estuary support year after year.

Mangroves are fish aggregating systems; they improve fish productivity. Fishes require a cool

area to breed in and mangroves provide that (Balasubramanian, 2006). Because the mangrove

swamps provide food security and the entanglement of roots shelter from fishing, many marine

and estuarine fishes come to the swamps for egg laying and for the sake of nursery for their

young ones before the parents depart to the oceans or into coral reefs and lagoons. The

mangroves are a critical habitat upon which these species depend for survival, and if something

happens to the mangroves, the future of these kinds of fish will be affected (Silas, 1986).

The breakdown of significant quantities of mainly the leaf litter in the mangrove swamp releases

significant amounts of nutrients and matter (Lu & Lin, 1990; Steinke et al., 1993) which supports

tree productivity and the mangrove food web. Mangrove forests tend to be net exporters of

organic matter. The nutritional value of detritus is increased by decomposing fungi and other

microbes. The fine particles of detritus form a food source for young ones of bivalves, shrimps

and fishes, which migrate into the mangrove environments for better feeding and protection.

Mangroves are, in short, breeding, feeding and nursery grounds for many estuarine and marine

organisms. More the mangroves better would be the catches of fishes, shrimps, and bivalves.

Honey is an important product obtained from the Sunderbans mangroves. Honeybees hold an

important position in the insect fauna of mangroves, for the production of large quantities of

honey and beeswax (Gopal and Chauhan, 2006). Flowers of Aegiceras corniculatum are good

sources of high quality white honey (Banerjee et al. 1989; Wealth of India, vol. I. 1985).

Avicennia marina & A. officinalis are also excellent sources of honey and bee wax (Banerjee et

al 1989).

Tender leaves of Acrostichum aureum are cooked and eaten (Wealth of India, vol. I., 1985).

Fruits of Bruguiera gymnorrhiza are considered edible (Kothari and Rao, 2002). Tender pods of

a leguminous climber Canavalia sp. are used as vegetable. Salvadora persica: Tender leaves and

shoots of Salvadora persica are used as salad; fermented drink is also made from fruits (Hajra

and Sanjappa, 1996). Fruits of Sonneratia caseolaris are edible, eaten raw or cooked; fruit juice

as a substitute for vinegar and as a condiment; tender leaves dressed with fish (-ibid-).


5

Mangroves for coastal protection: A number of studies have confirmed the function of mangroves in

terms of a green belt (Janssen & Padilla, 1999; IUCN, 2005). Among the most commonly known and

discussed roles of mangroves are those of providing coastal protection against storms, waves and

water currents, thus reducing erosion and flooding. Dense root system of mangroves, deeply

anchored in mud, help to reduce wave action, increase the sedimentation rate and enhance soil

consolidation and stability which provide a good form of natural coastal protection (Siddiqi,

1993).

The role of mangroves in protection of the life and property along the coast is being strongly

realized today after the 1999 super cyclone of Orissa and the tsunami of 2004. In October 1999,

a super cyclone, with wind speeds of 160 miles per hour struck Orissa and killed at least 10,000

people and rendered homeless 7.5 million. However, those human settlements located behind the

mangrove swamps suffered little loss. The villages in and around Bhitarkanika were spared much

of the cyclone’s fury because of the vast mangrove forest. Bhitarkanika is the second largest

mangrove formation in India, next only to the Sunderbans (Venkataraman, 2004).

Similar observations were made on December, 26, 2004 when the tsunami struck South-east

Asia and parts of south Asia. Those human settlements located behind the mangrove swamps

suffered little loss, according to observations from parts of Indonesia, Andaman and Nicobar, Sri

Lanka and Kerala, Tamil Nadu and Andhra Pradesh. Thirunal Thoppu, a fishing village of Tamil

Nadu coast having 172 families was saved from the wrath of this tsunami by the dense growth of

mangroves. In three other villages of Tamil Nadu coast also the tsunami damage was minimized

by mangroves. According to V. Selvum of M.S. Swaminathan Foundation: “Even though the

mechanical impact of a tsunami is enormous, and is bound to destroy the first line of mangroves,

the water suddenly slows down as it moves farther in” (Kremmer, 2006). In parts of South India,

with dense mangroves, fewer people suffered from this tsunami and less property was destroyed

compared to the areas without mangroves (Kathiresan and Rajendran, 2005).

That mangrove forests protect uplands from stormy winds, waves and floods had been well

known in the past. The amount of protection afforded depends upon the width of the forest.

Whereas very narrow fringe of mangroves offers only limited protection, a wider belt of

mangroves, with their entanglement of aerial roots, can considerably reduce wave and flood

damage to landward areas by absorbing the overflowing water. Mangroves can help prevent

erosion by stabilizing shorelines with their specialized root systems. This fact has been known to

the traditional gazni farmers of Aghanashini. Before the permanent stone bunds were built by the

State Government, the farmers used to prepare earthen bunds and fortify them on the tidal side

by planting of mangroves.


6

Mangroves build land or keep it from being washed away, which can be very important on

islands where land is so limited. Mud and sediment are often washed down by the rivers and

streams. When there is a mangrove swamp at the river mouth, the water spreads out into the

mangroves, and the sediment settles to the bottom where it is trapped by the mangrove roots. As

the bottom gets shallower, the mangroves can grow further out, while those on the inside

eventually find themselves on dry land, where they are replaced by land plants. In this way the

mangrove forest advances slowly outward, leaving land behind. Even in areas where enough

sediment is not available to build new land, the mangroves protect the shoreline from being

washed away in storms. The roots and trunks break the force of the waves, and the leaves and

branches reduce the effects of the wind and rain. There are examples of islands which were built

by mangroves, and then washed away when the mangroves were cut.

Maintenance of water quality: Mangroves filter water and maintain water quality and clarity.

In many parts of the world, mangrove deforestation is causing not only fisheries declines but also

causing degradation of clean water supplies.

Fixation of carbon dioxide: Mangrove deforestation is causing release of more carbon dioxide

into the atmosphere. In fact mangrove forests fix more carbon dioxide per unit area than

phytoplankton in tropical oceans. M.S. Swaminathan (2005) states mangroves will serve as

carbon sink, helping to enhance carbon sequestration and thereby contributing to reduce the

growing imbalance between carbon emissions and absorption.

Source of salt resistant genes: Mangroves form a rare and unique group among flowering

plants because of their capacity to grow in flooded conditions and in their salt tolerance.

According to M.S.R. Foundation, Chennai they are genetic pools for salt resistant genes. The

Kagga rice variety of coastal Uttara Kannada, is one well known instance of certain amount of

salinity tolerance. The world is going to be in trouble soon because of the climate change. Sea

level is going to rise and seep into farming areas. The time comes soon we will need salt resistant

crops, and the mangroves could be potential sources of salt resistant genes for crop plants. The

Foundation has a genetic library of mangroves. The Foundation is involved in identifying and

transferring salt tolerance genes from mangroves to crops like rice and mustard

(Balasubramanian, 2006)

Medicine: Mangroves are a repository of unusual biochemicals on account of their modified

physiology to survive in stressful conditions of the intertidal zone. These include chemicals with

insecticidal and bactericidal properties. There are novel agrochemicals, gums and glues,

alkaloids, saponins, phenolics, steroids, terpenoids, amino acids, carbohydrates, proteins, fatty

acids, alkaloids, carotenoids, various mineral combinations etc. associated with tremendous

potential medical, agricultural, industrial, scientific importance. Presence of a ‘polysaccharide-

rich substance’ with antitumor activity in the fruit juice of Morinda citrifolia, which also showed


7

anticancer and analgesic activity has been reported. Mangroves have A variety of potential

applications in the fields of cholesterol control, anticancer (antileukaemic, sarcoma, lung cancer)

and antiviral applications, HIV and human immunodeficiencies, fungal resistance etc.

(Bhandaranayake, 2002) open up exciting innovative fields which could stimulate conservation

and enrichment of mangrove vegetation.

Acanthus ilicifolius (Kan: Holechudi): A shrubby plant, common in mangrove

community. Leaves and bark useful in nervous disorders; leaf paste application or

fomentation of the plant parts are useful in alleviating rheumatic pains (Banerjee et al.,

1989; Kothari and Rao, 2002). Decoction of plant with sugar candy and cumin used in

indigestion and acidity; also promotes urine; cure for dropsy and bilious swellings; leaves

as expectorant; decoction of roots for gargling in sore mouth and toothache; roots also

used in asthma, paralysis, leucorrhoea and debility (Wealth of India, vol. I, 1985).

Acrosticum aureum: A fern in mangrove areas. The rhizome paste useful for boils

(Naskar and Mandal, 1999).

Avicennia officinalis: Mangrove tree. Dry leaves smoked by the people of Kutch and

Saurashtra for relief from asthma (Banerjee et al. 1989). Resin from bark used as a

contraceptive in Java; fruits and unripe seeds used as a maturative poultice and as

cicatrizant of ulcers and abscesses (Wealth of India, vol. I, 1985).

Barringtonia racemosa (Kan: Samudraphala): Mangrove associate tree. Fruit for

treatment of cough, asthma and diarrhoea; used in the preparation of skin ointment.

Aromatic seeds used in stomachache and ophthalmia; seed kernel with milk for treating

jaundice (Wealth of India, vol. 2, 1988).

Caesalpinia crista: Mangrove associate climber. Tender leaves eaten in liver disorders;

leaf paste in water as external application in inflammatory swellings (Kothari and Rao,

2002). Root has diuretic properties and is useful in gravel and stone in bladder. Powdered

seeds with sugar and goat’s milk reported to cure liver disorders; powder of baked

kernels with honey used in parts of Kerala to cure hernia and swellings (Wealth of India,

vol. 3, 1992).

Caesalpinia bonducella (Kan: Gajakakayi): Mangrove associate climber. Nuts have

diuretic and anti-fever properties; useful for treating diarrhoea; seeds used in ‘Ayush-64’

for treating malaria; seed infusion for cerbral haemorrhage and infantile convulsions;

seed oil is emollient and is used in cosmetics; it is antirheumatic (Wealth of India, vol. 3,

1992)

Calophyllum inophyllum (Kan: Honne): Mangrove associate tree. Paste of seeds to

relieve painful joints; oil for application on rheumatism and gout; oil cures scabies and

other skin diseases; soap from the oil has strong bactericidal and fungicidal properties;

camphor mixed oil for application on ringworm. Oil shows anti-bacterial activity against

several gram positive bacteria and used for treating burns (Wealth of India, vol. 3, 1992).


8

Excoecaria agallocha: Mangrove tree. Roots to cure hand and feet swellings (Kothari

and Rao, 2002).

Morinda citrifolia (Kan: Ainshe, Tagase): Mangrove associate tree. Roots applied to

gout; leaves applied to wounds and ulcers; juice of leaves externally applied to gout.

Fruits used for spongy gums, throat complains, dysentery etc (Wealth of India, vol. VI,

1962)

Phyllanthus reticulatus: Mangrove associate shrub. Leaf juice for bleeding gums;

powdered roots in sores and burns (Kothari and Rao, 2002).

Premna corymbosa: Mangrove associate climbing shrub. Root extract as cardiac tonic, in

stomachache and liver troubles (ibid).

Salvadora persica: Mangrove associate shrub. Fresh root applied as a vesicant (Hajra and

Sanjappa, 1996),

Sonneretia caseolaris: Mangrove tree. Fruits used in preparation of poultice for sprains

and swellings (Hajra and Sanjappa, 1996).

Thespesia populnea: Mangrove associate tree; very rare in Honavar Forest Division.

Leaves, flowers and fruits applied in skin diseases.

Vitex negundo: Mangrove associate shrub. Leaf juice in rheumatism, hair tonic; leaf

infusion anti-cancer; roots for piles; flowers in watery eyes (ibid).

Dyes: Avicennia officinalis bark yields a natural dye (Banerjee et al., 1989). Bruguiera

gymnorrhiza bark yields a black dye, which with treatment, turns orange-red, brown and violet

(Wealth of India vol. 2, 1988). Leaves of Clerodendron inerme, mangrove associate shrub yield

brown dye (Kothari and Rao, 2002). Kandelia candel bark is a source of dye used for dyeing

clothes red and brown (ibid.). Morinda citrifolia (Kan: Ainshe, Tagase, Noni), mangrove

associate tree, from the roots of 3-4years old trees natural dye extracted and used for dyeing silk,

cotton and wool into red, purple and chocolate shades; since the arrival of synthetic dyes this

traditional dyeing practice has almost stopped (Siva, 2007). Rhizophora mucronata bark is a

source of dye (Kothari and Rao, 2002) Vitex negundo plant ash for dyeing (ibid).

Fodder: Acanthus ilicifolius is cut before flowering, spines removed and used as fodder (Wealth

of India vol. I, 1985). Avicennia officinalis leaves, rich in protein (12.3% of dry weight) and

carbohydrates (56.7%) and various minerals, used as fodder (Wealth of India vol. I, 1985); often

the plants are lopped; used for feeding buffaloes. Cynodon dactylon (Karki grass): Used as a

fodder in coastal Uttara Kannada. Cyperus malaccensis, abundantly present in Sharavathi river

is collected in large quantities for local use as fodder. Porteresia coarctata, grass tolerant of high

salinity is good for fodder. Leaves of Kandelia kandel, Morinda citrifolia, Rhizophora apiculata,

R. mucronata etc. have fodder value. According to Bandaranayake (1998) mangrove fodder is

considered superior due to their high salt and iodine content.


9

Timber, firewood: Aegiceras corniculatum has Reddish brown to black wood, streaked with

yellow or orange- pink used for knife handles and as stakes for oyster beds (Wealth of India,

vol.I, 1985). Avicennia officinalis yields durable timber; for construction and oil mills (Banerjee

et al, 1989). Bruguiera gymnorrhiza timber is good for construction; trees grow up to 36 m

found in Andamans. (ibid). Calophyllum inophyllum wood for furniture and boats. Light wood

of Excoecaria agallocha suitable for floats, toys etc. Morinda citrifolia is good for handicrafts.

Rhizophora apiculata, Sonneretia alba, Thespesia populnea etc. yield timber. Wood of S.

caseolaris is for making models, musical instruments and boats (Hajra and Sanjappa, 1996).

Paper pulp: Excoecaria agallocha wood is used for making paper pulp (Banerjee et al, 1989).

Bruguiera gymnorrhiza wood pulp used for blotting and corrugated paper (Wealth of India, vol.

2, 1988).

Seed oil for lighting, and as fuel: Seed oil of mangrove associates Cerbera manghas and

Calophyllum inophyllum were traditionally used for lighting. Today the latter species, a

mangrove associate, is emerging as an important biofuel source and saplings are prepared in

thousands in the coastal forest divisions of Karnataka to plant along the coastal zones. Seed oil of

Pongamia pinnata (mangrove associate) is also used as bio-fuel and is also being propagated in a

big way. This species is also a mangrove associate.

Manure: Acanthus ilicifolius is considered good manure for coconuts in coastal villages of

Honavar. Leaves of Pongamia pinnata, Kandelia candel are used as manure. Oil cake of

Calophyllum inophyllum used as fertilizer; it is also good to control nematicides (Wealth of

India, vol. 3, 1992).

Fibre: Hibiscus tiliaceus yields strong fiber from bark used for ropes, mats etc. (Kothari and

Rao, 2002). Derris trifoliata yields strong fiber from the stem (Banerjee et al., 1989).

Mat and basket weaving: The sedge Cyperus malaccensis and leaves of Pandanus fascicularis

are used for mat and basket weaving.

Ground water protection from salinity: Sharp changes have been noticed in salt

concentrations of groundwater at the interface between salt flats and mangroves implying that

the mangrove systems can modify the salinity of the groundwater by lowering it drastically (Ridd

and Sam, 1996).

Perfumes: Pandanus fascicularis flowers used as source of perfume. Acacia farnesiana (Kan:

Kasturi jali): a mangrove associate tree small tree, native of tropical America, from the bright

yellow bunch of flowers yields the famous Cassie perfume of Cannes in France (Wealth of India,

vol.2,1985).


10

Tannin: Mangroves are very rich in tannins used for leather tanning, wood preservation, anti-

microbial actions, manufacture of plastics, paints, ceramics and water softening agents etc. They

impart flavor to wines Members of the families Avicenniaceae, Rhizophoraceae, and

Sonneratiaceae are rich source of tannins (Bandaranayake, 2002). Bark of Aegiceras

corniculatum, Avicennia spp, Bruguiera gymnorrhiza, Calophyllum inophyllum, Kandelia

candel, Rhizophora spp. Sonneretia caseolaris; seed oil of Pongamia pinnata used for tanning

(Banerjee et al., 1989; Kothari and Rao, 2002; Wealth of India, vol-1; 1985; Vol. 2, 1988).

Netting thread is boiled with the stems and leaves of Bruguiera, to make it strong (Wealth of

India, vol-2, 1988). In Uttara Kannada traditional nets are boiled with bark of Rhizophora to

make them stronger.

Fish food: Decomposed leaves of Avicennia marina make good feed for fish (Banerjee et al.

1989). That fish comes to feed on decomposing Avicennia and Rhizophora leaves in mangrove

swamps has been experimentally proved by Rajendran and Kathiresan (2002). They found there

was about 3 times more catch near the mangrove vegetation traps than in control waters.

Powdered leaves of Acanthus ilicifolius used as feed for fish and prawns in aquaculture. Dry

weight of leaves contain 21% carbohydrates, 13.55% lipids and 1.87% protein nitrogen; leaves

are also rich in minerals (Wealth of India, vol-I; 1985).

Study, recreation and tourism: Mangroves, of late, are turning out to be important centres of

nature study. The scenic beauty and biodiversity of estuaries with mangroves being higher, they

are often centres of recreation and tourism, being used for boating and fishing, bird watching etc.

in Papua New Guinea (Paijmans and Rollet, 1977). India has tremendous potential in developing

coastal eco-tourism, in which well protected mangrove wetlands can play important role.

Sunderban wetlands have become a paradise for tourism. With the rich bird population, healthy

growth of mangroves furnishing emerald hue to the placid waters of Aghanashini during winter

and summer months there exist great potential for sustainable eco-tourism. Sharavati estuary

lined with mangroves has unexplored tourism potential.

Potential donors of genes for salt resistance: Mangroves can be potential donors of genes for

salt tolerance in crop plants. Yensen (2006) considers the 21st Century likely to be the century of

halophyte agriculture expansion, as diminishing fresh water resources put pressure on

civilization to utilize the vast saline soils and aquifers. Trillions of dollars are lost annually even

in mildly saline fields that could be billions of dollars gained from new salt-loving crops. It has

been calculated that 1.0 - 1.5 billion hectares of land are salt-affected on the earth. While much

of this land occurs in the Middle East, Central Asia, Northern Africa and Australia it seems that

no country is free of salinity issues. The majority (90%) of salt-affected land is naturally saline

(primary salinization). Each year, approximately two million hectares still go out of productivity


11

due to salinity. The salt-affected lands world-wide, may be resource opportunities for

halotechnologies, such as halophyte crops and landscape plants, which grow better under high

salinities.

Miscellaneous: Acacia farnesiana, related to Karijali, is a source of gum; Avicennia officinalis:

Wood ash mixed with paints to make the latter adhere more firmly (Wealth of India, vol-I, 1985)

Barringtonia racemosa Seeds oil and bark for bio-insecticide (Wealth of India, vol-2).

Calophyllum inophyllum (Kan: Honne): Seed oil used as varnish; locally used for coating fishing

crafts. Used as a lubricant in place of castor oil; refined oil for soap making and for industries

(Wealth of India, vol-3, 1992). Pongamia pinnata: Seed oil used for soaps (Kothari and Rao,

2002). Salvadora persica: Twigs used as toothbrush. Soneretia caseolaris: Spongy

pneumatophores for corks and handicrafts.

1.2 Mangroves – Global scenario

The influences exerted by the environmental factors such as climate and hydrological as well as

other physico-chemical conditions determine the extent of mangrove distribution. One of the

important factors of mangrove distribution is temperature that determines the growth and

distribution of the mangroves (Chapman, 1977).

Mangroves dominate approximately 75% of the world’s tropical coastline (Table 1.2) between

250N and 250S latitude (Figure 1.1). This restricted distribution of mangroves is mainly due to

the sensitivity of the species to frost and cold temperature. The most northerly site of the

mangrove distribution are the top of the Red Sea in the Gulf of Aquba (300N) and South Japan

(320N); while the most southerly sites for mangrove distribution are Australia (380S) and

Chathan island east of New Zealand (440S). The total mangrove cover of the world is about

1,81,000 sq.kms. Over the period, there is significant decrease of mangrove cover in many

countries due to various manmade changes and natural consequences. The highest concentration

of mangrove species is, however found in the Indo-Malaysian region. The key mangrove species

belong to the families Rhizophoraceae, Avicenniaceae and Sonneratiaceae.

Mangroves of the world have been divided into two groups: Eastern group i.e. East Africa, India,

Southeast Asia, Australia and the Western Pacific and Western group comprises of West Africa,

South and North America and the Carribean Countries. Out of the ninety mangrove species of

the world, 63 occur in Indian Ocean & West-Pacific regions while only 16 species are recorded

in the Pacific-America, 16 species in Atlantic-America and 11 species in West Africa. In the

eastern group, there are in all 20 species belonging to 9 families whereas in the Western group

there are only four species belonging to 3 families. The species are Rhizophora mangal,

Laguncularia racemosa, Avicennia nitida & A. tomentosa Approximately 43% of the World’s

mangroves are located in just four countries- Indonesia (42,550 sq.kms), Brazil (13,400 sq.kms),

Australia (11,500 sq.kms) & Nigeria (10,515 sq.kms).


12

Table 1.2. Mangroves of the World (Source:Spalding et al, 1997)

Region Mangrove area(ha) % to Global area

South and Southeast Asia 75,17,300 41.0 Australia 18,78,900 10.4 Americas 49,09,600 27.1 West Africa 27,99,500 15.5 East Africa and the Middle East 10,02,400 5.5

Total 1,81,07,700 100

Figure 1.1: Global distribution of mangroves 1.3 Distribution of Mangroves in India

In India, mangrove vegetation is observed all along its 5,700 km coastline. The total area covered

by mangroves has been estimated to be about 700,000 ha which amounts to about 6% of the

world’s mangroves. However these fragile and sensitive trees and their ecosystem have been

abused, neglected and overexploited in India. The major threats to mangroves are deforestation,

reclamation and lately pollution also.

India’s coastline can be divided into two parts viz. Western coast on the Arabian Sea and the

Eastern coast on the Bay of Bengal. Western coastline includes five states, viz Gujarat,

Maharastra, Goa, Karnataka and Kerala. The Eastern coastline consists of states of West Bengal,

Orissa, Andhra pradesh, Tamilnadu and Andaman & Nicobar Islands. However, the distribution,

extension and number of species in these areas differ according to the physiographic formation


13

of the coast. The west coast is more or less steeply shelved, lacks major deltas and river estuaries

and is dominated by sandy and rocky substratum. On the other hand, the east coast is shallow,

largely influenced by major deltas and river estuaries and mostly dominated by the deltaic

alluvium hence the extent of mangrove cover along the east coast of India is comparatively

larger (90%) than the west coast (10%). Mangroves in India comprise of 69 species (excluding

those of salt marshes and mangrove other associate species, under 42 genera and 27 families. Of

these, 63 species (41 genera under 27 families) are present on the East coast; 37 species (25

genera under 16 families) on the West coast; and 44 species (28 genera under 20 families) on the

Bay Islands. The East coast has 91% of mangrove species and the West coast has 53%. The most

dominant mangrove species found along the east and west coast of India are Rhizophora

mucronata , R. apiculata, Bruguiera gymnorrhiza, B. parviflora,, Sonneratia alba, S.

caseolaris, Cariops tagal, Heretiera littoralis , Xylocarpus granatum, X. molluscensis, Avicennia

officinalis, A. marina, Excoecaria agallocha, Lumnitzera racemosa. The National Remote

Sensing Agency (NRSA) recorded a decline of 7,000 ha of mangroves in India within the six-

year period from 1975 to 1981. In Andaman and Nicobar Islands about 22,400 ha of mangroves

were lost between 1987 and 1997 (Table-1.3). Over the last two decades mangrove afforestation

is also being attempted, with reasonably good progress in Karnataka, more so in Uttara Kannada

and Kundapur.

Table. 1.3. State wise mangrove cover (in sq. km.)

Sr. No.

States/Union Territory

Estimated by Forest Survey of India Estimated by States

SAC, Ahmedabad

1987 1989 1991 1993 1995 1997 1999 2001 1987 1992

1 Andaman & Nicobar

686 973 971 966 966 966 966 789 1190 771

2 Andhra Pradesh

495 405 399 378 383 383 397 333 200 372

3 Goa 0 3 3 3 3 5 5 5 200 6

4 Gujarat 427 412 397 419 689 901 1031 911 260 991

5 Karnataka 0 0 0 0 2 3 3 2 60 127

6 Maharashtra 140 114 113 155 155 124 108 118 330 0

7 Orissa 199 192 195 195 195 211 215 219 150 187

8 Tamil Nadu 23 47 47 21 21 21 21 23 150 30

9 West Bengal 2076 2109 2119 2119 2119 2123 2125 2081 4200 1619

Total 4046 4255 4244 4256 4533 4737 4871 4481@ 6740 4123


14

1.4 Mangrove Scenario in Karnataka

The coastal Karnataka is divided into 3 Districts – Dakshina Kannada, Udupi and Uttara

Kannada: The Dakshina Kannada and Udupi seaboard lies between 12°27’ and 13°58’ north

latitude and 74°35’ and 75°49’ east longitude. It is about 177 kilometer in lengths, about 80

kilometers at its widest part. From north to south, it is a narrow strip of territory and from east to

west it is a broken low plateau, which spreads from the Western Ghats to the Arabian Sea. The

major part of its length lies along the seaboard. The area is intersected by many coast parallel

rivers and streams and presents varied and most picturesque scenery. The length of the coastline

is almost straight, but broken at places with numerous splits by rivers, rivulets, creeks and sandy

ridges and bays.

Among the principle rivers of the two districts are the Netravati, Gurpur, Sitanadi, Swarnanadi,

Kollur, Haladi and Chakra; and a few rivulets like Udiyavara, Shiroor and Baindur. Major

estuarine complex of Dakshina Kannada and Udupi districts with sizable mangrove spread are

the Netravati-Gurpur estuary, the Mulki-Pavanju estuary, the Udayavara-Pangala estuary, the

Swarna-Sita-Kodi estuary, the Chakra-Hatadi-Kollur estuary, the Baindur hole estuary and the

Shiroor hole estuary (Rao & Suresh, 2001).

According to a report submitted by Chandran, M.D.S. (2007-unpublished) to EMPRI, Bangalore,

based on survey of 11 estuaries 14 mangrove species were observed (Table 1.4). The Table

shows that highest number of mangroves (14 sp.) is found in the Kali estuary, followed by

Haladi-Chakra-Kollur estuary (12 sp.) Aghanashini and Mulki-Pavanje (11 sp. each), Gangavali,

Venktapur and Udyavara (10 sp. each) and the remaining with lesser numbers. The bigger

estuaries tend to have more numbers, an exception being Netravati-Gurpur (7 sp.). In the

Sharavati estuary, because of constant release of fresh water from the hydel projects from

upstream the salinity level is very low and therefore we do not find high salinity tolerant species

like Avicennia marina and Rhizophora apiculata. Low salinity to nearly fresh water conditions

favour good growth of Sonneratia caseolaris throughout the estuary, except towards its very

mouth. All the estuaries of Honavar Forest Division do not have Lumnitzera racemosa and

Bruguiera cylindrica. A lone tree and few saplings of Bruguiera gymnorhiza were found

growing in Venktapur estuary, being absent in other estuaries of the Division. Some of the other

mangroves associated with lower salinity conditions are Kandelia candel, Acrostichum aureum

and Acanthus ilicifolius.


15

Table-1.4. Estuary-wise distribution of mangroves in Karnataka

Sn Mangrove species Name of estuary

NG MP UD SS HC BA VE SH AG GA KA

1 Acanthus ilicifolius P P P P P P P P P P P

2 Lumnitzera racemosa - - - - P - - - - - P

3 Excoecaria agallocha P P P P P P P P P P P

4 Aegiceras corniculatum - P P P P - - P P P P

5 Bruguiera cylindrica - - - - - P - - - - P

6 B. gymnorhiza - P P P P - P - - - P

7 Kandelia candel P P P P P - P P P P P

8 Rhizophora apiculata - - - - - - - - P P P

9 R. mucronata P P P P P P P P P P P

10 Sonneratia alba - P P P P P P P P P P

11 S. caseolaris P P - P P - P P P - P

12 Avicennia marina - P P P P - P - P P P

13 A. officinalis P P P P P - P P P P P

14 Acrostichum aureum P P P P P - P P P P P

Total 7 11 10 11 12 5 10 9 11 10 14

Dakshina Kannada: 1. NG: Netravati-Gurpur; 2. MP: Mulki-Pavanje. Udupi: UD: 1. Udyavara; 2. SS: Sita-Swarna-Kodi; 3. HC: Haladi-Chakra-Kollur; 4. BA: Baindur. Uttara Kannada VE: Venktapur; SH: Sharavati; AG: Aghanashini; GA: Gangavali; KA: Kali

1.5 Mangrove Scenario in Uttara Kannada District The Uttara Kannada District Sea Board lies between 74° 9’ to 75°10’ east longitude and 13° 55’

to 15° 31’ north latitude and extends over an area of 10,327 Sq. km. The district has three main

and distinctive regions: the Coastlands, the Sahyadri range and Eastern margin where the

tableland begins. Relief and climate have introduced these regional differences. The coastlines

are the best-developed area with a high degree of economic development and a high density of

population. It is in this region, Karwar, Ankola, Kumta, Honavar and Bhatkal taluks are located.

The five important rivers of Uttara Kannada are Kalinadi, Gangavali, Aghanashini Sharavathi

and Venktapur. Notable rivulets/creeks are Belekeri, Ankola, Alvekodi and Badgani. The mouths

of rivers and rivulets have several mangrove habitats.

Uttara Kannada District experiences typical tropical climate. There are no cold months. Yet the

higher reaches of the Ghats [around 800M] experience a cooler climate than the coast. The

rainfall varies from about 300 cm or more along the coast and the Ghats, down to 100 cm along

the eastern fringes. Most of the rainfall is monsoonal & falls from June to August. Weather from

December to April will be invariably dry. Summer temperature can go beyond 40°C in some

places. The types of soils in these Taluks are Black cotton soil, Red loam, Black clay & forest

soil. Details of Division-wise area under forests are given in Table 1.6


16

The mangrove zone towards the river mouth, having higher salinity, is known as ‘euhaline’.

Along the coast of Uttara Kannada, the river mouths are rocky and with strong wave action, and

not suitable for mangroves. This is unlike the deltaic river mouths of the east coast, where

mangroves can grow luxuriantly. The euhaline zone has salinity range from 30 ppt to 40 ppt.

The zone behind is called ‘polyhaline’ where the wave action is less and salinity ranges from 18

ppt to 30 ppt. The substratum is sandy clay. This region is ideal for mangroves like Sonneratia

alba, Rhizophora spp., Avicennia spp., Bruguiera spp., Acanthus ilicifolius etc. The third zone,

still behind is ‘mesohaline’ where salinity ranges from 5 ppt to 18 ppt. It has silty clay bottom

and feeble wave action. The mangroves of this zone are Kandelia candel, A. ilicifolius,

Rhizophora spp., Aegiceras corniculatum, S. alba etc. (Rao and Suresh, 2001). The estuary-wise

list of mangroves in Honavar Forest Division is given in Table 1.5.

Table 1.5. Distribution of mangroves in Honavar Forest Division (*present)

No Species Gangavali Aghanashini Sharavathi-Badgani

Venktapur

True mangroves 1 Acanthus ilicifolius P P P P

2 Acrostichum aureum P P P P

3 Aegiceras corniculatum P P P P

4 Avicennia marina P P P P

5 A. officinalis P P P P

6 Bruguiera gymnorrhiza P 8 Excoecaria agallocha P P P P

9 Kandelia candel P P P P

10 Porteresia coarctata P P P P

11 Rhizophora apiculata P P P

12 R.. mucronata P P P P

13 Sonneratia alba P P P

14 S. caseolaris P P P

Mangrove associates 15 Barringtonia racemosa P 16 Caesalpinia bonducella P 17 Calophyllum inophyllum P P P

18 Capparis spp. P 19 Cerbera manghas P P 20 Clerodendrum inerme P P P P

21 Cyperus malaccensis P 22 Caesalpinia crista P P P P

23 Derris scandens P P 24 Derris trifoliata P P P P

25 Dolichandron spathacea P P

26 Erythrina indica P P P P

27 Ficus racemosa P P P

28 Pandanus fascicularis P P P


17

29 Pongamia pinnata P P P P

30 Premna corymbosa P P P P

31 Salvadora persica P

32 Sporobolus virginicus P

33 Thespesia populnea P

1.6 Forest Administration

Kanara Circle: The Kanara Circle came into existence on 1st January 1967 with headquarters at

Dharwad. The headquarters was shifted to Sirsi in 1993. Its territorial jurisdiction covers the

entire Uttara Kannada District. The Circle has 6 Territorial Forest Divisions, 1 Wild Life

Division and 1 Social Forestry Division with the headquarters respectively at Haliyal, Honavar,

Karwar, Sirsi, Yellapur, Dandeli & Karwar (Figure 1.2). The territorial divisions are divided

into 14 Sub-divisions. The Wild Life Division, Dandeli has 2 Sub-divisions, Dandeli & Anshi.

The Circle has 39 territorial Ranges and 10 S.F headed by Range Forest Officers. There are 155

Sections under Foresters & 477 Beats headed by Forest Guards. The Government Timber

Depots in the Circle are situated at Dandeli, Kirwatti, Mundgod, Kadra, Hattikeri, Katgal,

Idugunji, Kabbinhakkal, Chipgi & Manmane. The Govt. Timber Depot at Dandeli, Kirwatti &

Mundgod are managed by Asst. Conservator of Forests & others by Range Forest Officers.

Table. 1.6. Division-wise total forest in Kanara Circle

Sl. No.

Division Forest Area in Sq. Km.

% of the forest area to total forest area.

1. Haliyal 1183.4456 14.26

2. Honavar 1409.4286 16.99

3. Karwar 1419.5893 17.11

4. Sirsi 1718.2817 20.71

5. Yellapur 1689.8666 20.37

6. W.L.Dandeli 875.8451 10.56

Total 8296.4569 100.00

Source: ADM Report Kanara Circle 2010

1.6 Methods: Inventorying and mapping of mangroves involved

Field survey in estuaries and creeks of Honavar Forest Division for mangroves and

potential area available for planting with mangroves;

On field survey of estuary and creek-wise mangrove patches (both linear and patch-wise)

were studied for species composition;


18

Study of mangroves patches for basal area estimates using 10x10 sq m quadrats. Where

quadrat making was difficult point centred quarter method was used. Opportunistic

counting was attempted too.

GPS was used to locate mangrove patches, linear formations etc. and demarcate them on

the maps.

Intertidal areas were identified using Google imageries, field surveys and bathymetric

maps, so as to demarcate mangrove areas suitable for planting purposes

Data was collected from the Forest Department on forest administration details,

demarcation of Range, Section and Beat boundaries etc.

Remote sensing imageries of MODIS for years1989, 2000, 2003 and IRS p6L4 MX5

2010 were used for the major estuaries and their buffer zones of 1 km adjoining, to track

changes in land use land cover over a period of time. Higher resolution imageries of IRS

p6L4 MX5 2010 were useful in finding out distribution and area estimates of especially

tree mangroves.

Figure 1.2. Kanara Circle


19

Area calculation using GIS:

Step 1: Mangrove areas (areas under canopies of mangrove crowns) and Potential areas (exposed areas

during low tides, without mangrove crowns, excluding seasonal sand bars and bivalve beds) have been

digitized as separate vector polygon layers using Google Earth, Bing map & Geo-referenced IRS images.

Step2: These polygons (regions) are overlaid on forest ADM vector maps & village vector maps (based

on Census 2001) and split using polygon split into smaller units in correspondence with forest beat as an

ADM unit.

Step3: Each region’s spatial tables are updated with coordinate extractor, region area (in ha) and

perimeter. Data is converted in to GPX format and uploaded into GPS.

Step4: Using GPS, sample regions are surveyed for species distribution & some decisive hydro-biological

parameters, especially salinity and associated mangroves, incorporated in the region. Using this data

Isolines are created for possible distribution of such parameters in the estuaries and creeks studied.


- 19 -

2. IDENTIFICATION OF MANGROVES

Most mangroves are woody plants, shrubs and trees. There are also few herbs, mainly some

grasses and sedges. Among the woody plants one is a lower plant- a fern namely Acrostichum

aureum (Figure 2.1); this fern grows in colonies in swampy and marshy places where the tidal

force is low and salinity is not that high. The important mangrove families and their members

found in Honavar Forest Division are described here.

I. TRUE MANGROVES

Family: Rhizophoraceae

This is the most important family of mangroves. The members are woody plants, usually trees.

The family has spectacular development of aerial stilt roots. These roots spring from the main

stem and also the branches; they branch repeatedly and grow downwards and give additional

support to the tree in the soft mud. The aerial roots, studded with tiny air passing windows

known as lenticels, visible to the naked eye, also help in aeration.

The trees have opposite, simple, dark green leathery leaves. The terminal bud is protected by a

long cover made up of stipules. These stipules fall off when new leaves emerge. The members of

the family produce from the fruits long, green, cylindrical propagules. These on maturity detach

from the fruit and fall vertically into the mud, where they strike roots and become daughter

plants. If the propagules happen to fall when the substratum is flooded during high tides they

may be carried away by water currents; On reaching suitable swampy places they develop into

new plants. This interesting phenomenon of reproduction is called ‘vivipary’. Here apparently

the mother plant is giving birth to daughter plants.

Members of Rhizophoraceae can be identified using the following key:

Calyx 8-16 lobed; petals 2 lobed : 1. Bruguiera

Calyx 4-6 lobed; petals not lobed:

Calyx 4 lobed; petals without apical outgrowths : 2. Rhizophora

Calyx 5-lobed; petals with apical outgrowths;

Stamens more than 12 : 3. Kandelia


- 20 -

1. Bruguiera:

We have only one species in the Honnavar Forest Division, namely B. gymnorrhiza. It is

a tree with rough corky bark; stem base may be flattened into buttresses. Leaves elliptic

to oblong elliptic with a narrow tip; but not ending in a narrow long point as in

Rhizophora. Leaf size 7-14 cm by 4 to 6 cm. Leaf stalks and midrib red coloured.

Flowers in singles, reddish coloured; calyx 10-16 lobed, red to pinkish; petals bilobed,

outer margin with silky hairs. The fruit produces a propagule of 10-15 cm. which is

slightly angled (Figures 2.2-2.3). Small trees were found at Hegle in Venktapur river of

Bhatkal. In Andamans it grows to 36 m, and is buttressed.

2. Rhizophora

R. mucronata: Trees reaching maximum height of 10 m in the Division. Numerous

branched stilt roots arise from the base of the stem. Some arise from the branches also.

Leaves 10-18 cm X 4-10 cm, broad and elliptic; the leaf tip is produced into a narrow

outgrowth called mucro; leaf base blunt to obtuse. Flowers are produced in long clusters,

each cluster having 4-8 flowers. Petals are hairy and stamens 8. The propagule, a long

green, smooth cylindrical structure, reaches a maximum length of 65 cm (Figure 2.4).

Note: Both Rhizophora mucronata and R. apiculata are found in the Division. The former is the commoner

and widely used for afforestation.

R. apiculata: A smaller tree, reaching 4-5 m in the Division. Stilt roots arising from main

stem as well as from branches form impenetrable barrier beneath the canopy. Leaves

elliptic lanceolate with a smaller narrow bristle like point towards the narrow tip. Size 10-

20 cm X 5-8 cm. Leaf base conical; leaf middle vein reddish. Flowers in pairs in upper

leaf axils, without stalks; petals not hairy; stamens 12. Propagules 30-50 cm long

(Figures 2.5, 2.6).

3. Kandelia candel

Small trees reaching 5-6 m high. Leaves narrower than Rhizophora, oblong shaped.

Flowers white, in dichotomously branched inflorescence axis. Calyx 5 lobed, reflexed;

petals 5, divided into numerous fine branches. Stamens numerous. Propagule cylindrical,

green, narrowed towards the tip, 30-40 cm long. The trees have flesh coloured base

flattened into buttresses; stilt roots closely adpressed to the stem base. Bark reddish

brown, peeling off into flakes (Figure: 2.7)

Note: Found commonly in all estuaries


- 21 -

Family: Sonneratiaceae

Buttresses absent; pneumatophores (breathing roots) corky and soft, rising vertically into the

air from the mud. Leaves opposite, simple; flowers large with numerous free stamens.

Sonneratia alba: Small trees reaching maximum of 5 m. Many corky pneumatophores stick

out of the mud from all around the tree. Leaves opposite, elliptic, oblong, blunt at apex,

narrowed at base; Flowers 2-3 together; calyx has a cup shaped part and 6-8 lobes which are

distinct in fruit. Petals white, small; stamens numerous, free, white; ovary depressed globose.

Fruit somewhat spherical, many seeded with calyx remaining in the fruit. Natural regeneration

is plentiful especially in shallow places with low tidal effects (Figures 2.8-2.9).

Note: Found in all rivers except Sharavathi

Sonneratia caseolaris: Trees up to 12 m height; soft corky pneumatophores longer than S.

alba, reaching up to 1 m. Young stem 4-angled. Leaves almost without stalk, much narrowed

at base, opposite. Leaf tip has a pore known as hydathode through which excess salt is

secreted. Flowers reddish purple, in singles at the tip of branches; stamens numerous, reddish.

Fruits depressed globose (Figures 2.10-2.11)

Note: Most common mangrove tree in Sharavathi; Rare in other rivers; not found in Gnagavali, although Rao &

Suresh (2001) present it as a cpmmon species there. It prefers places with low salinity; the Sharavathi river,

where fresh water from the dams is constantly released appears to be ideal for it.

Family: Avicenniaceae

Shrubs or trees without buttresses. Breathing roots (pneumatophores) numerous and

protruding from the mud all around the tree. Leaves opposite, without stipules; flowers

yellow. Fruit one seeded, dry when mature.

Avicennia marina: Shrubs or small trees upto 4 m high. Bark smooth yellowish brown.

Leaves 3-6 X 2.2.5 cm, elliptic oblong or ovate, narrowing to an acute tip; leaf base rounded

or narrowing. Flowers small, stalkless, yellowish clustered towards tips of floral axis; stamens

not projecting out from the corolla. Fruit at maturity ovoid with a pointed tip, slightly

flattened (Figures 2.12, 2.13).

Note: Very common in Gangavali, rare in Aghanashini, common in Alvekodi creek, absent in Sharavathi and

Badgani, moderate in Venktapur.

Avicennia officinalis: Larger trees, reaches 8-10 meters in Honavar Forest Division;

exceptional individuals of 12 m are found in the sacred grove of Masurkurve in Aghanashini.

Smooth whitish gray bark; pneuatophores seen all around the tree. In addition masses of

branching stilt roots hang from the upper part of the trunk and base of large branches. Leaves


- 22 -

5-7.5 cm X 2.5- 3.25 cm, ovate, oblong with more or less rounded leaf tip. Small, yellow

stalkless flowers seen in clusters towards the tip of floral axis. Flowers distinguished from A.

marina by stamens seen projecting outside the corolla (Figures 2.13-2.14)

Note: Found in all the rivers of the Division.

Family: Myrsinaceae

Plants without pneumatophores; flowers with 4 sepals and 4 petals; and superior ovary.

Aegiceras corniculatum: Shrubs or small trees with slender stilt roots. Leaves 4-8 cm X 2-4

cm, alternate, ovate-oblong or obovate, may have a small notch at the blunt tip; leaf base cone

like. Flowers small, white, fragrant in umbellate bunches. Propagules which come out of the

fruits are 3-4 cm long and curved with pointed tips (Figures 2.15-2.16).

Notes: Found in all estuaries along edges and banks away from strong tides; notable for fragrant white flowers

Euphorbiaceae

Plants with latex. Male and female flowers in separate clusters

Excoecaria agallocha: Large shrubs or small trees occurring along the edges of the swamp,

on bunds and on wet soils. Acrid, blister causing latex present. Numerous serpentine roots

produced from base of stem. Leaves alternate, margins entire or mostly minutely toothed;

leaves turn red before shedding (Figures 2.17-2.18).

Acanthaceae

Family of herbs and shrubs. Flowers not regular in shape.

Acanthus ilicifolius: A shrubby plant growing in colonies in shallow parts of the swamp.

Leaves opposite, stiff, wavy and with sharp spines along the margin. Flowers large, blue

(Figure 2.19)

Poaceae

The members are grasses. In the estuaries these grasses are found often forming meadows

submerged during high tides and exposed during low tides.

Porteresia coarctata: A stiff erect grass growing in meadows in open shallow parts of the

estuaries (Figure 2.19)


- 23 -

II. MANGROVE ASSOCIATES

Numerous species of plants occur in association with the mangroves. These are not obligate

mangroves and higher salinity is not often a prerequisite for their growth. They may also be often

associated with inland habitats. These plants have certain degree of salinity tolerance. They often

grow along the margins of swamps, or on estuarine bunds. Details of notable mangrove

associates are found in Table 2.1.

Table 2.1. Details of notable mangrove associate species in Honavar Forest Division

Sn Name Family Remarks

1 Cerbera manghas

(Kan: Cande) Apocynaceae Shrub or small tree with white latex and

white flowers and mango sized green

fruits; old fruits fibrous

2 Barringtonia racemosa

(Kan: Samudraphala)

Barringtoniaceae Small to medium tree with 15-30 cm long

leaves, and pink flowers in long hanging

inflorescences.

3 Dolichandron spathacea Biganoniaceae Tree close to coastal swamps with white

fragrant flowers, and long bean like

compressed cylindrical pods

4 Capparis spp. Capparidaceae Spiny climber on bunds

5 Crateva magna

Capparidaceae Small trees on the bank of Aghanashini

near NH bridge; leaves 3 foliate;

yellowish flowers with hard fruit.

6 Calophyllum inophyllum

(Kan: Honne)

Clusiaceae Large evergreen tree; white fragrant

flowers and greenish yellow ripe fruits

with a single seed.

7 Cyperus malaccensis Cyperaceae Grass; abundant in Sharavathi

backwaters.

8 Diospyros embryopteris Ebenaceae Small evergreen tree with guava sized

gummy fruits.

9 Bridelia scandens Euphorbiaceae Climbing shrub with greenish yellow

flowers small bluish-black fruits.

10 Acacia farnesiana

(Kan: Kasturijali)

Fabaceae Thorny bush or small tree; leaves with

minute leaflets; flowers yellow, fragrant.;

pod dull brown & inflated.

11 Acacia nilotica Fabaceae Small trees, rare on the coast; leaflets

small; flowers golden yellow in globose

heads.

12 Caesalpinia bonducella

(Kan: Gajagakai)

Fabaceae Climber with curved sharp prickles;

compound leaves; yellow fragrant

flowers; dark brown dry pod 1-2 seeded.

13 Caesalpinia crista Fabaceae Large woody climber; stem and leaves

with sharp curved prickles; flowers

fragrant, yellow; pod one seeded.


- 24 -

14 Derris scandens (Kan:

Handiballi)

Fabaceae Woody climber with rosy flowers

15 Derris trifoliate Fabaceae Woody climber common on the coast

16 Erythrina variegata

(Indian coral tree; Kan:

Varjipe)

Fabaceae Soft & light wooded tree, branches

covered with small black prickles; leaves

with 3 foliage; coral coloured flowers.

17 Pongamia pinnata

(Kan: Honge)

Fabaceae Medium sized tree with compressed pods,

growing often near water courses, sea

beaches and rarely on estuarine banks.

18 Prosopis juliflora Fabaceae Shrub or small trees with drought

resistance.

19 Hibiscus tiliaceous Malvaceae Shrub or small tree with yellow flowers

changing to pink in the evening.

20 Thespesia populnea

(Kan: Hoovarase)

Malvaceae A medium sized coastal tree with heart

shaped leaves on long stalks and yellow

flowers resembling cotton flowers.

21 Ficus racemosa

(Kan: Atti)

Moraceae Tree with milky latex and hollow, edible,

fleshy false fruits.

22 Morinda citrifolia

(Kan: Ainshe, Tagase)

Rubiaceae Small tree with large leaves, dense heads

of white flowers and glossy green fruit,

white when ripe.

23 Pandanus fascicularis

(Kan: Ketaki)

Pandanaceae A palm-like, but branched shrub with

narrow very long spinous leaves with

small flowers on dense axis covered with

white or light yellow, very fragrant bracts

24 Cynodon dactylon Poaceae Karki grass forming meadows in open

shallow part of estuaries

25 Sporobolus virginicus Poaceae Grass; perennial grass with good sand-

binding properties.

26 Salvadora persica

(Tooth-brush tree; Kan:

Gonimara)

Salvadoraceae Much branched shrub or small tree; rare

along the bunds of Aghanashini; small

round fruits dark red when ripe.

27 Clerodendrum inerme Verbenaceae Shrub with white flowers

28 Odina wodier

(Kan: Gojal)

Verbenaceae Medium sized deciduous tree with minute

flowers in panicles and small, reddish,

compressed fruits with one seed.

29 Premna corymbosa Verbenaceae Shrub

30 Vitex negundo

(Kan: Lakkigida; Nokki)

Verbenaceae Shrubs, young stem 4-angled; aromatic;

leaves 3-5 foliate; terminal leaflet longer

32 Vitex trifolia Verbenaceae Shrubs, young stem 4-angled; leaves 3-

foliate; leaflest without stalks


25

Plate 2.2 Porteresia coarctata – a

mangrove grass

Plate 2.3 Acrostichum aureum – a

Mangrove Species

Figure 2.1. Acrostichum aureum

Figure 2.2. Bruguiera gymnorrhiza

Figure 2.3 . B. gymnorrhiza - flower

Figure 2.4. Rhizophora mucronata


26

Figure 2.6. Rhizophora apiculata Figure 2.7. Kandelia kandel

Figure 2.5. Rhizophora apiculata


27

Figure 2.8. Sonneratia alba flower Figure 2.9. Sonneratia alba young fruits

Figure 2.9. Sonneratia caseolaris flower Figure 2.10. Sonneratia caseolaris young fruit

Figure 2.11. Avicennia marina flower Figure 2.12. Avicennia marina fruits (note: stamens do not protrude outside the corolla) Note narrowing leaf tips


28

Figure 2.13. Avicennia officinalis. Note rounded leaf tip Figure 2.14. A. officinalis

flowers. Note stamens coming out of corolla

Figure 2.15. Aegiceras corniculatum in flowers; Figure 2.16. A. corniculatum fruits


29

Figure 2.18. E. agallocha aerial roots

Figure 2.17. Excoecaria agallocha in flowers

Figure 2.19. Acanthus ilicifolius Figure 2.20. Porteresia coarctata in

Gangavali estuary


30

3. MAGROVES OF HONAVAR FOREST DIVISION

3.1. ADMINISTRATIVE JURISDICTION FOR MAGROVES

Honavar Forest Division (lat.13º 56’ 15” to 14º 41’ 15”N and long.74º 26’ 0” to 74º 46’ 20”E), is

situated towards the Indian west coast and is one of the five forest divisions Kanara Forest

Circle, that has its jurisdiction over the entire Uttara Kannada district of Karnataka State (Figure

3.1.1). The division covers the forest areas of Kumta, Honavar and Bhatkal taluks and part of

Ankola taluk along the coastal Uttara Kannada. It is bounded by forest divisions of Kundapur to

the south,, Sirsi and Sagar toward east, Karwar to the north and the Arabian Sea on the western

side. There are four notable west flowing rivers with their respective estuaries that merge with

the Arabian Sea, viz. Gangavali, Aghanashini, Sharavathi and Venkatapur. The division receives

heavy rains from the South-west Monsoon averaging nearly 4000 mm per year. The mean

maximum & minimum temperature of the region lies in 27.33 (±5.86)ºC and % of relative

humidity is 87.5(±7.5). The division has three sub divisions at Kumta, Honavar and Bhatkal six

forest ranges namely Hiregutti, Katgal, Kumta, Honavar, Manki, Gersoppa and Bhatkal. It covers

134082 ha (Table.3.1.1) of forest area which is of tremendous ecological and environmental

importance being part of the Western Ghats. The forests are of evergreen, semi-evergreen and of

secondary moist deciduous types. Considerable areas of forest tree plantations, many of them

dating back to over one century are present here.

Table 3.1.1: Area-wise administrative categories of forests area in Honavar Forest Division (area in ha)

Range Reserved forest Protected forest

Village forest

Total forest area

Total geographical

area

% forest area

Proper forest

Minor forest Hakkal Betta

Bhatkal 9421 9846 759 0 0 20026 27066.6 73.99

Gersoppa 18084 2731

0 0 20815 23362 89.10

Hiregutti 13162 6679

371 444 20656 29294.4 70.51

Honavar 9258 9796

514 0 19568 24151.6 81.02

Katgal 16175 3700

58 0 19933 23455.5 84.98

Kumta 12942 5489

192 1956 20579 28088.7 73.26

Manki 11297 7640 253 0 0 19190 24151.6 79.46

Total 90339 45881 1012 1135 2400 140767 179570.4

Source: Working Plan for the Honavar Forest Division 2003 to 2013


31

Figure 3.1. 1: Honavar Forest Division administrative map


32

Honavar Forest Division: Salient Features: The human population of Kumta, Honavar and

Bhatkal talukas within the division was 482,482 as per 2011 census & as per 2007 livestock

census the cattle number was 108,338 and there were also 20,763 buffaloes. The rock formation

is granitic and lateritic type and soil is lateritic with several variations in color and texture. The

division has one hydroelectric power generation at Gersoppa, the Sharavathi Tailrace project,

which caused submergence 700 ha of forest area. The taluk-wise rainfall details are given in

Figure 3.1.2

Figure 3.1.2. Taluk-wise annual rainfall in Honavar Forest Division (1989 to 1998)

Mangrove area distribution and suitable areas for planting: Areas under mangroves were

estimated estuary-wise and total area given in Table 3.1.2. The same table also contains the

number of mangrove patches for Honavar Division (1549 patches). Range-wise mangrove areas

are given in Figure 3.1.3. Mangrove forests cover about 391 ha only, which makes just 0.28% of

total forest area in the district. Suitable areas for mangrove planting constitute about 1019 ha, of

which range-wise details are given in Figure 3.1.4. Despite small area mangroves they are

highly integral to coastal ecology and productivity, fisheries and bird conservation as well as

carbon sequestration and needs to be protected and enhanced with great care. While making this

estimate we have not taken private holdings suitable for mangrove planting. If unused estuarine

rice fields and abandoned shrimp farms are brought under mangroves, through the Government

purchasing such areas from owners or through any other schemes mangroves in the division

could be increased several times more. Range-wise estimates show that Honavar Range with an

estimated 129 ha of mangroves leads in area while least was in Manki Range with just 4 ha.


33

Hiregutti Range with 708 ha leads in suitable area for mangrove planting whereas it was

practically nil in Manki Range.

Table 3.1.2. Area estimates for mangroves and suitable areas for planting in Honavar

Forest Division

Table 3.1.3. Range-wise area estimates for mangroves and suitable area for planting in Honavar

Forest Division

Sn. Range Mangrove area (ha)

Suitable area for planting

(ha)

No. of mangrove

patches

No. of potential areas for planting

1 Bhatkal 36.4 22.8 231 40

2 Manki 4.0 0.5 22 3

3 Honavar 127.8 161.1 449 136

4 Kumta 50.4 90.7 468 82

5 Katgal 84.1 35.7 133 19

6 Hiregutti 88.2 708.4 246 50

Total Div 390.74 1019.10 1549.00 330.00

To enable mangrove management at grassroots level of forest administration Section-wise and

Beat-wise details of areas under mangroves were estimated as well as suitable area available for

planting (details in Table 3.1.4 & 3.1.5 & Figures 3.1.5 -3.1.8. See also Annexures I-XI)

Division Name Honavar

Total Geographical area (ha) 179,570.40

Forest area (ha) 140,767.00

No. of mangrove patches 1549

Mangrove area (ha) 390.74

Total area for planting (ha) 1019.10


34

Figure 3.1.3. Range-wise division of mangrove area in Honavar Forest Division

Figure 3.1.4. Rangewise % of potential area for mangrove planting in Honavar Forest Division

2%

0.5%

16%

9% 3%

70% Bhatkal

Manki

Honavar

Kumta

Katgal

Hiregutti


35

Table 3.1.4: Forest Section-wise area under mangroves and potential area for mangrove planting

in Honavar Forest Division

Sl.No. Section Section

geographical area (ha)

No. of mangrove

areas

Mangrove area (ha)

No. of potential

areas for

planting

Total area for

planting (ha)

Range

1 Belke 6294.0 4 0.2 0 0.0 Bhatkal

2 Bhatkal 8074.0 103 25.4 21 8.7 Bhatkal

3 Shirali 8584.0 124 10.8 19 14.1 Bhatkal

4 Mavalli 6405.0 17 3.4 NA NA Manki

5 Manki 6314.0 5 0.6 3 0.5 Manki

6 Hadinbal 4831.0 6 0.8 1 0.5 Honavar

7 Honavar 13440.0 407 117.1 129 156.1 Honavar

8 Salkod 7332.0 36 10.0 6 4.5 Honavar

9 Chandavar 15410.0 468 50.4 82 90.7 Kumta

10 Katgal 5907.0 4 0.2 NA NA Katgal

11 Mirjan 3287.0 129 83.9 19 35.7 Katgal

12 Hiregutti 5894.0 50 21.9 7 157.7 Hiregutti

13 Madangeri 7233.0 190 61.9 38 549.3 Hiregutti

14 Gundubala 8533.0 6 4.3 5 1.4 Hiregutti

Total 107538.0 1549 390.7 330 1019.1


36

Figure 3.1.5: Sectionwise area (ha) under mangroves

Figure 3.1.6: Sectionwise number of mangrove patches

Figure 3.1.7: Sectionwise total area (ha) suitable for mangroves planting

Figure 3.1.8: Sectionwise number of potential areas for mangrove planting


37

Table 3.1.5: Beat-wise details of number of mangrove areas, total area, and area suitable

for planting


38

Figure. 3.1.9: Beat-wise mangrove area vs number of patches

Fig 3.1.10: Beat-wise potential area for plantation vs no. of suitable areas available for

planting


39

3.2. ESTUARY-WISE MANGROVE SITUATION IN HONAVAR FOREST DIVISION Mangrove vegetation is found associated with the estuaries and creeks of the Division.

Obviously, before any kind of agricultural interventions by humans, over 3000 years ago,

mangrove vegetation, expectedly, would have been intact in all suitable habitats. With the

introduction of agriculture good portions of shallow estuarine areas were reclaimed by

preparing earthen embankments to protect large stretches shallow estuarine portions for

raising salinity tolerant rice varieties like Kagga. Cleared of mangroves these estuarine fields

or ‘gaznis’ were cultivated with Kagga variety of rice especially during the rainy season,

when the fields get flooded and salinity levels decline substantially. The farmers also adopted

the practice of planting rows of mangrove trees, just outside these bunds to fortify them from

collapse. After the harvest of rice towards the end of the rainy season the bunds were opened

to allow the tidal waters inside, through sluice gates, and fisher-folks were allowed to fish in

the ‘kodis’ or tidal channels within these gaznis.

This traditional system of estuarine cultivation with mangrove planting was a sustainable

system. Maintenance of some patches of mangrove forests as sacred, as in the Masurkurve

island in the Aghanashini estuary, dedicated the deity Babrudevaru, is a notable example of

traditional conservation. This traditional system suffered a severe setback with the

replacement of earthen embankments for gazni fields with permanent stone bunds, beginning

in 1960’s. As these bunds are stronger the farmers felt no need to fortify them further with

planting of mangroves alongside. On the contrary, in many places the existing mangroves

were cut down or domestic use. Moreover the arrival of prawn farming from early 1980’s

caused all suitable portions of estuaries getting converted into shrimp ponds, after clearing

every trace of woody vegetation. This was quite devastating on the estuarine ecosystem as a

whole.

A realization on the importance of mangrove vegetation dawned during the late 1980’s, and

the Government, some institutes like the Indian Institute of Science and NGO’s like

Snehakunja, Kasarkod, entered the arena for spreading awareness on mangroves and

attempting planting in sample plots, especially in Aghanashini estuary. But it was through

systematic programmes of mangrove planting by the Forest Department, beginning in late

1990’s, that estuaries started turning greener with mangroves. The formation of village forest

committees in estuarine villages promoted peoples’ involvement and better protection was

afforded to the mangroves. When the present survey was undertaken to map the mangroves

of Honavar Forest Division, under sponsorship of the Karnataka Forest Department, much

progress was already achieved in raising of mangrove plantations. An estuary-wise status of

mangroves is presented in this chapter.

Estuary and creek-wise mangrove areas and potential areas: Through field surveys using

GPS and remote sensing imageries (Google Earth and IRS) we mapped mangrove areas

available in the division estuary and creek-wise. Among the estuaries Aghanashini topped the

list with 169 ha of mangroves and 711 ha of potential area followed by Sharavathi-Badgani


40

estuarine complex (136 ha and 184 ha respectively)- Table 3.2.1 and Figure 3.2.1 for details.

Creeks are small but nevertheless should not be ignored.

Table 3.2.1:. Estuary and creek-wise details of mangrove area and potential area

Sn Estuary name Mangrove area(ha)

Potential area (ha)

Total water spread Area

(ha)

1 Gangavali estuary, 45.93 95.29 817.10

2 Aghanashini estuary 169.40 711.00 5236.00

3 Kumta creek 14.23 42.42 238.10

4 Dhareshwar creek 1.43 2.57 4.02

5 Sharavathi-Badgani estuarine complex 136.20 184.40 3415.00

6 Apsarkonda creek 0.14 0.00 1.30

7 Manki creek 0.62 0.47 21.63

8 Mavalli creek 3.06 0.00 17.80

9 Murudeshwar creek 0.37 0.00 35.37

10 Venkatapur estuary 20.54 22.77 219.20

11 Jali creek 0.02 0.00 5.40

12 Bhatkal creek 1.69 0.00 53.22

13 Huvilmadi creek (Hadeen Creek) 0.10 0.00 13.71

14 Belke creek 0.12 0.00 5.97


41

Mangroves in relation to salinity: Mangroves have different preferences for salinity levels.

During the rainy seasons all mangroves can survive extremely low salinities approaching

almost the levels of fresh water conditions. It is the dry season salinity that is decisive for

mangrove distribution within an estuary. Estuarine salinity, in natural state is between that of

sea water (normally 35 ppt) and fresh water (<0.5 ppt). The salinity keeps fluctuating with

tides and seasons. In normal conditions salinity increases towards the river mouth

approaching nearly sea water salinity and lowers progressively in upstream areas where the

river water meets the salt water tides. Mangroves, broadly can be classified into high salinity

(>15 ppt) tolerant, medium salinity (5-15 ppt) tolerant and low salinity (<5 ppt) tolerant. The

details of such mangroves present in the Honavar Division are given in Table 3.2.2.

Table:3.2.2: Mangrove species in relation to different salinity ranges

Mangroves sp. > 15 ppt

(High salinity) 5-15 ppt

(Medium salinity) < 5 ppt

(Low salinity)

Acanthus ilicifolius

Acrostichum aureum

Aegiceras corniculatum

Avicennia marina

Avicennia officinalis

Bruguiera gymnorrhiza

Excoecaria agallocha

Kandelia candel

Rhizophora apiculata

Rhizophora mucronata

Sonneratia alba

Sonneratia caseolaris A. MANGROVES OF GANGAVALI ESTUARY

The Gangavali or Bedti River forms the northern boundary of Honavar Forest Division, along

the coast (Figure 3.2.2), A narrow range of hills separate Gangavali basin from that of

Aghanashini further south. The river has its origin in two streams in the Dharwad district

namely Shalmala and Bedti. These two join near Kalghatgi (Dharwad dist) and flow towards

Uttara Kannada as Bedti River, known as Gangavali in the coast. It has a total length of 161

km, out of which 96 km lies in Uttara Kannada. The sea water moves in the Gangavali River

for almost a distance of 24 km upstream to the village Gundbala. The river has 571 ha of

estuarine water spread area and 3 small islands. The mangroves of Gangavali mostly belong

to the fringe type and occur alongside the tidal part of the river in linear patches. Some denser

mangrove habitats are found in the villages Nadumaskeri (Gangavali), Agragon, Hadav,

Joog, and Ulware. Dense mangroves, linear mangroves and sapling areas (recently planted)

are also shown in the figure.


42

Waterscape/landscape elements: Of the 571 ha of estuarine area about 13 ha towards the

river mouth is covered with sand bars and sandy shores. The mud-flats of the estuary cover

around 75.55 ha. The mud flats are submerged during high tides. Mud flats may be sandy, of

sandy silt or silty sand. They are very productive areas and especially the sand mixed mud

flats support the molluscan fisheries of great value to the local communities. The sandy flats

are not suitable for mangroves. Those parts with finer silts covering around 39.5 ha and are

the only areas suitable for mangrove afforestation. The mangrove vegetation as such cover

about 41.6 ha. The mangrove patches, in general, have an estimated 428 trees/ha (as inferred

from point-centered quarter and 10x10 m quadrats). Mud flats are often subjected to

variations in their morphology and extent depending on the annual floods and silt deposits.

Natural succession of mangroves may be expected in some of the mud flats (Table-3.2.3 and

Figure-3.2.2 also shows sediment nature).

Table 3.2.3: Characterisation of waterscape/landscape elements of Gangavali estuary

Elements Sub elements Area in

ha Suitability for planting

A Sandbar/deposits - 12.84 Mangrove associates may be planted

B Mudflat

(75.55ha)

Sandy 5.33 Part of ecosystem- no planting recommended

Bivalve beds 30.67 No planting recommended Potential for mangrove planting

59.29 Mangroves recommended

C Existing

Mangrove area - 45.92

Total water spread area*

B+C+open water area+salt pans etc 817.1

*The waterspread area includes the entire estuary which gets covered during high tide Mangroves and potential mangrove areas - village-wise distribution: Details regarding

existing mangrove areas adjoining the villages of the estuarine complex including estimated

tree density/ha and potential area available for planting with mangroves are furnished in

Table-3.2.3. Out of the 13 villages bordering the estuary only Nadumaskeri, which has the

largest area under mangroves (18.57 ha) falls in Kumta taluk. Nadumaskeri also has the

highest potential area (17.24 ha) suitable for mangrove planting. The other villages which

have lesser area under mangroves and also for planting, come under the Ankola taluk (Table-

3.2.4 and Figure-3.2.1.2 ). The tree density of these is reasonably good although the tree

statures are not good, almost all less than 8 m in height. The survey points are numbered in

the figure. Village-wise area under mangroves along with tree density and area suitable for

planting are shown in Table-3.2.4.


43

Figure 3.2.2: Gangavali estuary showing mangrove areas, bottom sediment nature

Table 3.2.4: Village-wise details of mangrove area, tree density and potential area available for planting in Gangavali estuary

Sn Village Taluk Mangrove

area in ha.

Tree density per ha.*

Potential area available for planting (ha)

1 Nadumaskeri Kumta 17.24 433 18.57 2 Agragon Ankola 2.45 383 2.86 3 Belse Ankola 0.07 nil 4 Bilehoingi Ankola 11.05 506 4.01 5 Hadav Ankola 1.70 644 5.16 6 Hichkad Ankola 0.05 nil 7 Honnebail Ankola 0.09 nil 8 Joog Ankola 4.73 309 4.97 9 Kodsani Ankola 0.45 nil

10 Manjaguni Ankola 0.09 2.04 11 Sagadgeri Ankola 0.33 300 nil 12 Shirur Ankola 2.31 460 1.96 13 Ulware Ankola 1.09 367 nil

Mangroves: patches and linear formations: Mangroves may occur in patches of high

density or may be linear formations fringing the estuary and its inlets. For both these

formations we have estimated tree density/ha of mangroves. Tree density has increased in

recent years on account of high density planting (Table-3.2.5 & Figure-3.2.2)

0 1 2

Kilometres

A r a

b i a

n S

e a

Belse

Kamge

Kodsani

Agragon

Manjaguni

Nadumaskeri

Honnebail

HadavBilehoingi

Joog

Shirur

Hichkad

74

.35

°E7

4.3

5°E

74

.35

°E7

4.3

5°E

74

.35

°E7

4.3

5°E

74

.35

°E7

4.3

5°E

74

.35

°E

14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N

74.

325

°E7

4.32

5°E

74.

325

°E7

4.32

5°E

74.

325

°E7

4.32

5°E

74.

325

°E7

4.32

5°E

74.

325

°E

74.

375

°E7

4.37

5°E

74.

375

°E7

4.37

5°E

74.

375

°E7

4.37

5° E

74.

375

° E7

4.37

5° E

74.

375

°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

Gangavali river

Gangavali river

Gangavali riverGangavali river


Gangavali river


Kanagil

Sagadgeri

Ulware

111111111

222222222

333333333

555555555

777777777

888888888

999999999

101010101010101010

111111111111111111

121212121212121212

131313131313131313

141414141414141414

151515151515151515

171717171717171717

181818181818181818

191919191919191919212121212121212121

222222222222222222

232323232323232323

252525252525252525

262626262626262626

282828282828282828 292929292929292929

303030303030303030

313131313131313131

323232323232323232

333333333333333333

343434343434343434

353535353535353535

363636363636363636 373737373737373737

383838383838383838

393939393939393939

404040404040404040

414141414141414141

434343434343434343

I N D E X

Survey points

Mangrove Types

Dense (32)Linear (89)Saplings (26)

Mudflats

Sandy (7)Sand bar (8)Silty sand (19)

1

Gangavali estuary

0

Village

I N D I A


44

Table 3.2.5: Details of village-wise mangrove area and estimated tree and sapling density/ha

Sn Village Taluk

Patch mangrove

Linear mangrove

Mangrove saplings

Area (ha)

Tree Density/ ha*

Area (ha)

Tree density/

ha*

Area ha.

Density/ ha.*

1 Nadumaskeri Kumta 12.77 498 2.46 200 2.02 463 2 Agragon Ankola 0.35 500 1.31 433 0.79 328 3 Belse Ankola 0.07 4 Bilehoingi Ankola 5.28 492 1.97 622 3.80 405 5 Hadav Ankola 0.85 488 0.85 800 6 Hichkad Ankola 0.05 7 Honnebail Ankola 0.09 8 Joog Ankola 4.26 396 0.33 275 0.13 300 9 Kodsani Ankola 0.45

10 Manjaguni Ankola 0.09 11 Sagadgeri Ankola 0.27 400 0.07 200 12 Shirur Ankola 0.87 1.43 460 13 Ulware Ankola 0.22 500 0.73 200 0.14 400

Total 41.65 478.90 23.72 419 9.54 365

Mangrove sample study localities and species: Mangroves (both patch and linear) were

studied in 43 localities within the estuary as per details given in Table-3.2.6. The

eumangroves or true mangroves found were Avicennia marina, A. officinalis, Excoecaria

agallocha, Kandelia candel, R. apiculata, R. mucronata and Sonneratia alba. Acanthus

ilicifolius is a gregariously growing mangrove undershrub. It forms larger patches in silted

and stagnant water areas along the estuarine belt. Acrostichum aureum is a fern especially

found in lesser saline, water stagnant areas. Some of the mud flats towards the estuarine

mouth had formations of high salinity tolerant grass Porteresia coarctata, a close relative of

rice plant.


45

Table 3.2.6: Sample study details, habitat type, area, tree density and dominant species

Sn Long. Lat. Village Taluk Patch/linear Area (ha)

Tree density/

ha.*

Dominant sp. (including shrubs)

1 74.2966 14.5921 Nadumaskeri Kumta Patch 0.11 100 Sonneratia alba, Avicennia marina

2 74.2983 14.5907 Nadumaskeri Kumta Patch 0.27 533 S. alba 3 74.2988 14.5927 Nadumaskeri Kumta Patch 1.15 786 S. alba

4 74.2990 14.5906 Nadumaskeri Kumta Patch

0.98 557 S. alba, Rhizophora mucronata, A. marina


0.20 500 S. alba, R. mucronata, A. marina




6.71 600 R. mucronata, S. alba, A. marina



9 74.3093 14.5982 Nadumaskeri Kumta

Patch

2.21 340

Avicennia officinalis, Excoecaria agallocha, A. marina, R. mucronata

10 74.3140 14.5964 Nadumaskeri Kumta Linear 0.36 400

E. agallocha, A. marina, Acanthus ilicifolius


E. agallocha, A. officinalis, A. ilicifolius


E. agallocha, A. officinalis, A. ilicifolius

13 74.2924 14.5973 Nadumaskeri Kumta Saplings 0.52 400 E. agallocha 14 74.3003 14.5923 Nadumaskeri Kumta Saplings 0.27 200 S. alba, E. agallocha

15 74.3044 14.5953 Nadumaskeri Kumta Saplings 0.60 700 A. marina, R. mucronata

16 74.3045 14.5947 Nadumaskeri Kumta Saplings 0.20 550 A. marina

17 74.3135 14.5986 Agragon Ankola Patch 0.13 500 E. agallocha, A. marina, A. ilicifolius

18 74.3188 14.5940 Agragon Ankola Linear 1.12 433

A. officinalis, A. ilicifolius, E. agallocha, Kandelia kandel

19 74.3148 14.5989 Agragon Ankola Saplings 0.32 250 R. mucronata, A. marina



22 74.3134 14.6066 Bilehoingi Ankola

Patch

0.49 380

K. candel, A. officinalis, R. mucronata, E.agallocha


46


Patch

3.93 595

A. officinalis, A. marina, E. agallocha, A. ilicifolius


Patch

0.86 500

K. candel, A. officinalis, R. mucronata, E. agallocha

25 74.3192 14.6101 Bilehoingi Ankola Linear 0.53 567


26 74.3205 14.6118 Bilehoingi Ankola Linear 0.41 700 A. officinalis, A. marina

27 74.3216 14.6130 Bilehoingi Ankola Linear 0.37 600 A. officinalis, A. marina

28 74.3149 14.6069 Bilehoingi Ankola Saplings 1.82 330






31 74.3215 14.6056 Hadav Ankola Patch 0.85 488 A. officinalis

32 74.3290 14.6137 Hadav Ankola Linear 0.71 800 A. officinalis, A. marina

33 74.3290 14.6044 Joog Ankola Patch 4.26 396


34 74.3335 14.6065 Joog Ankola Linear 0.18 350 A. officinalis

35 74.3390 14.6019 Joog Ankola Linear 0.07 200 E. agallocha, A. officinalis

36 74.3312 14.6052 Joog Ankola Saplings 0.05 100 A. officinalis 37 74.3359 14.6050 Joog Ankola Saplings 0.08 500 A. officinalis

38 74.3506 14.6009 Sagadegeri Ankola Linear 0.27 400 E. agallocha, A. ilicifolius, A. officinalis

39 74.3533 14.5993 Sagadegeri Ankola Saplings 0.07 200 A. officinalis 40 74.3474 14.6057 Shirur Ankola Saplings 1.43 460 A. officinalis

41 74.3616 14.5966 Ulware Ankola Patch 0.22 500 E. agallocha, A. officinalis

42 74.3620 14.5969 Ulware Ankola Linear 0.14 200 E. agallocha, A. officinalis

43 74.3822 14.5983 Ulware Ankola Saplings 0.09 400 A. officinalis


47

Recommendations for mangrove planting High salinity tolerance is exhibited by Sonneratia alba, Avicennia marina and Rhizophora spp.

A. officinalis grows in medium salinity areas. Kandelia candel is found in medium and low

salinity areas. Excoecaria agallocha can tolerate a wide range of salinity. We reaffirm that the

mudflats that support bivalves (mollusca), as indicated in Table-5 are to be excluded from

any disturbance as they are of tremendous economic importance to the local communities

and also of high ecosystem value. Table-3.2.7 in combination with Figure-3.2.3 will provide a

clear picture of the mangrove tree species that can be raised in different localities. Salinity zones

(high, medium and low) are demarcated in Figure 3.2.4 and species for high, medium and low

salinity zones recommended are given in Table 3.2.8.

Table: 3.2.7. Village-wise potential area for mangrove planting and location-wise recommended species for planting in Gagavali estuary

Sl.No. Longitude Latitude Village Taluk Type of

Sediment

Area in

Ha. Preferable Mangrove

1 74.2945 14.5983 Nadumaskeri Kumta Sand 2.88 Mangrove associates 2 74.2963 14.5988 Nadumaskeri Kumta Sand 0.68 -do- 3 74.2967 14.5979 Nadumaskeri Kumta Sand 1.08 -do-

4 74.3021 14.5963 Nadumaskeri Kumta Sandy 24.34

Bivalve Bed – all bivalve beds to be excluded

5 74.2914 14.5983 Nadumaskeri Kumta Sand bar 2.42 Mangrove associates 6 74.2924 14.5980 Nadumaskeri Kumta Sand bar 2.53 -do-

7 74.2974 14.5933 Nadumaskeri Kumta Sandy silt 6.64 S.alba, R. mucrinata, A.marina, K.candel

8 74.3043 14.5945 Nadumaskeri Kumta Sandy silt 9.71

S.alba, A.marina, E.agallocha, R.apiculata

9 74.3142 14.5981 Nadumaskeri Kumta Sandy silt 2.22 E. agallocha, A. officinalis, K. candel

10 74.3142 14.5988 Agragon Ankola Sandy silt 2.14 A. officinalis, R. mucronata

11 74.3177 14.6005 Agragon Ankola Sandy silt 0.67 A. officinalis, R.mucronata, K.candel

12 74.3221 14.6033 Agragon Ankola Sandy silt 0.05 R. mucrinata, A. officinalis, K. candel

13 74.3125 14.6029 Bilehoingi Ankola Sandy silt 0.03 R. mucrinata, A.officinalis, K.candel

14 74.3135 14.6063 Bilehoingi Ankola Sandy silt 0.62 R. mucrinata, A.officinalis, K.candel

15 74.3142 14.6072 Bilehoingi Ankola Sandy silt 0.73 A.officinalis, E.agallocha,

16 74.3150 14.6037 Bilehoingi Ankola Sandy silt 2.64 A.officinalis,


48

E.agallocha,

17 74.3206 14.6048 Hadav Ankola Sandy silt 0.88 A.officinalis, R.mucronata

18 74.3223 14.6073 Hadav Ankola Sandy silt 4.28 E.agallocha, A.officinalis,

19 74.2966 14.6004 Honnebail Ankola Sand 0.69 Mangrove associates 20 74.2877 14.6037 Honnebail Ankola Sand bar 2.29 Mangrove associates 21 74.2895 14.6029 Honnebail Ankola Sand bar 7.27 Mangrove associates 22 74.2936 14.6011 Honnebail Ankola Sand bar 1.03 Mangrove associates

23 74.3288 14.6049 Joog Ankola Sandy silt 4.03 R. mucrinata, A.officinalis, K. candel



26 74.2985 14.6029 Manjaguni Ankola Sand 6.33 Bivalve Bed 27 74.3042 14.6012 Manjaguni Ankola Sand 0.58 Mangrove associates

28 74.3116 14.6029 Manjaguni Ankola Sandy silt 2.04 A.officinalis, E.agallocha,

29 74.3474 14.6056 Shirur Ankola Sandy silt 1.43 E.agallocha, A.officinalis,



Table 3.2.8: Mangroves recommended for planting in potential areas

Sn Mangroves sp. Salinity zones

High

Medium Low

1 Avicennia marina √ 2 A. officinalis √ √ 3 Excoecaria agallocha √ √ 4 Kandelia candel √ √ 6 Rhizophora apiculata √ 7 R.. mucronata √ 8 Sonneratia alba √ √ 9 S. caseolaris √


49

Figure 3.2.3: Locations of potential area for planting mangroves and mangrove associates (numbered 1-41)

Figure 3.2.4: Salinity zones demarcated in Gangavali estuary

0 1 2

Kilometres

A r a b

i a n S

e a

Belse

Kamge

Kodsani

Agragon

Manjaguni

Nadumaskeri

Honnebail

HadavBilehoingi

Joog

Shirur

Hichkad

74

.35

°E74.3

5°E

74.3

5°E

74

.35

°E7

4.3

5°E

74

.35

°E74.3

5°E

74.3

5°E

74.3

5°E

14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N14.6°N

74.

325

°E7

4.3

25

°E7

4.32

5°E

74.

325

°E7

4.32

5°E

74.

325

°E7

4.3

25

°E7

4.32

5°E

74

.32

5°E

74

.37

5°E

74.

375

°E7

4.37

5°E

74

.37

5°E

74.

3 75

°E7

4.3

75

°E7

4 .37

5°E

74 .

375

°E7

4.3 7

5°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74.

3°E

74 .

3°E

74 .

3°E

74 .

3°E

74.

3°E

Gangavali river

Gangavali river



Gangavali river


Kanagil

Sagadgeri

Ulware

111111111

222222222

333333333

555555555

777777777

888888888

999999999

101010101010101010

111111111111111111

121212121212121212

131313131313131313

141414141414141414

151515151515151515

171717171717171717

181818181818181818

191919191919191919212121212121212121

222222222222222222

232323232323232323

252525252525252525

262626262626262626

282828282828282828 292929292929292929

303030303030303030

313131313131313131

323232323232323232

333333333333333333

343434343434343434

353535353535353535

363636363636363636 373737373737373737

383838383838383838

393939393939393939

404040404040404040

414141414141414141

434343434343434343

I N D E X

Survey points

Mudflats

Sandy (7)Sand bar (8)Silty sand (19)

1

Gangavali estuary

0

Village


50

Mangrove associates The names of plant species that live in association with mangroves, or growing towards the outer drier edges of the swamps, are mangrove associates. They may be present in the inland areas also. The location-wise list of mangrove associates studied is given in the Table 3.2.9. Table 3.2.9. Location-wise list of mangrove associates and their distribution in selected sample areas of the Gangavali estuary Sn Name of species Gangavali Bilihonge Uluvare Mudnur Sagadgeri Mogta 1 Caesalpinia bonducella* + 2 Caesalpinia crista + + + 3 Calotropis gigantea* + 4 Clerodendron inerme + + + 5 Cyperus arenarius + 6 Cyperus sp + + 7 Derris scandens + 8 Derris trifoliata + + + + 9 Erythrina variegata + + 10 Ficus racemosa + + 11 Hibiscus tiliaceus + + 12 Phoenix sp. + 13 Phyllanthus reticulatus + 14 Pongamia pinnata + + 15 Premna corymbosa + 16 Spinifex littoralis* + 17 Vitex negundo* + 18 Vitex trifolia* + 19 Zizyphus jujube* + * Present only on sand deposits Some notable mangrove localities

Nadumaskeri: Situated towards the mouth of the river it has some notable mangrove

patches. Mangroves are in very disturbed state, being cut down for local needs and

grazing mainly by buffaloes. The patches are dominated by the coppice growth of

Sonneratia alba, the average height of the coppice shoots being 2-3 meters. According to

some locals during the tsunami of December 2004, the mangrove areas of the river mouth

were inundated by sand, thereby affecting the regeneration of most mangroves. But at the

time of our study the swampiness had increased, and therefore, under protection

mangroves have every chance of good regeneration. Rhizophora apiculata occurs here

although somewhat rare. There is bushy growth of Avicennia marina towards the open

outer edges of the swamp. Bushes of Excoecaria agallocha occur towards the bund of the

river, on exposed land, where salinity can be very high. Most of the Sonneratia are


51

coppice from stumps. Cattle-grazing, is common. Seedlings of Rhizophora, planted by

the Forest Department, were observed amidst the Sonneratia patch. However,

Rhizophora requires more swampy conditions. An erect mangrove grass Porteresia

coarctata was found growing in almost pure patches forming meadows in the open

shallow parts of the estuary. Notable of the mangrove associates of Gangavali are Vitex

trifolia, Spinifex littoralis (both in open sandy places) and Clerodendrum inerme. A rare

patch of Caesalpinia bonducella, a medicinal plant was found on the sand dunes of the

river mouth.

Bilihoingi: A very swampy tidal inlet towards the northern bank of Gangavali this is

good habitat for mangroves. Most notable were Avicennia marina and A. officinalis.

Sparingly were found Sonneratia alba, Excoecaria agallocha and Kandelia candel. Rao

and Suresh (2001) reported A. alba as the most dominant species from Bilihonge, which

we could not trace however. Derris trifoliata occurs as a mangrove associate.

Clerodendrum inerme occurs in sandy exposed parts. The grass Porteresia coractata

occurs in open sandy parts of the swamp bordering the river. The Avicennias here attain

maximum height of 7 to 8 meters, and most trees have girth less than 1 m. Though there

are no nearby habitations, most trees bear marks of cutting of branches. The ground layer

is dominated by Acanthus ilicifolius.

Agragon: A promising patch of mangroves is found in this village. It is dominated by

fairly large trees of A. officinalis. These trees have a general height of 8-9 m and many of

them have girth nearing 1m or even exceeding it. R. mucronata is the common associate

of A. officinalis. Towards the shallower edges are found K. candel, A. marina, S. alba and

A. ilicifolius. At least, during the recent years, there appears to be no disturbance of this

patch of mangroves.

Sagadgiri: A small good patch of mangroves occurs along the tidal swamp close to the

ferry cross. It was dominated by A. officinalis. The largest tree here had a gbh of 172 cm

and height of 12 m. It is followed by K. candel of 6-7 m. The latter occurs regularly all

along the shallower edges. Drier part of the river-bank has E. agallocha. Other

mangroves were Aegiceras corniculatum (rare), R. mucronata (rare) and A. ilicifolius.

Derris trifoliata, Caesalpinia cristata, Hibiscus tiliaceus and Premna corymbosa are

climbers associated with mangroves. Occasionally found along the river bank were small

trees of Pongamia pinnata. The mangrove grass P. coarctata was also found.

Mudnur: Situated on the southern bank of the river this locality is notable for a narrow

strip of fringe mangroves and mangrove associates. The mangroves include several small

trees of K. candel followed by A. officinalis. Few bushes of A. corniculatum were also


52

found. Of the mangrove associates at higher ground are Erythrina variegata and Ficus

racemosa.

Ulvare: This village situated along the southern bank of Gangavali has narrow strip of

fringe mangroves dominated by E. agallocha. This small tree has profuse production of

branches from below. It is ideally suited for perching along the steep sides of the river

bank. Occasionally found is A. officinalis, one individual of which has attained a

remarkable gbh of 210 cm. There are several Ficus racemosa, bearing fruits in various

stages of maturity. Others are D. trifoliata, C. inerme, C. crista and Z. mauritiana.

There are evidences of planting of Rhizophora; but most propagules we observed were

lifeless, may be due to the presence of the steep embankment and lesser swampiness of

the habitat. A. officinalis and K. candel would thrive here better.

Mogta: This village situated further away from the coast has some fringe mangroves

bordering the bottom of the steep embankments. These include occasional A. officinalis,

K. candel and E. agallocha. Higher along the edges of the river are mangrove associates

D. trifolia, D. scandens, H. tiliaceus, Vitex negundo, Phyllanthus reticulatus and

Pongamia pinnata. There are tell-evidences in this village of natural recolonisation of

mangroves in parts of the fields abandoned due to invasion of tidal water. Formerly there

was a sluice gate to stop the inundation of salt water through a natural kodi (tidal

channel). This sluice gate, reportedly, got damaged several years back causing tidal

invasion of the fields, especially during the highest tides of full moon and new moon

days. The permanently wetter parts of this narrow creek and its sides are getting

colonized by A. officinalis, K. candel, A. corniculatum, R. apiculata, A. ilicifolius and the

mangrove fern Acrostichum aureum. The place provides good evidence of how mangrove

succession can naturally happen in suitable habitats, if humans do not destroy them.

Spatial mapping using remote sensing data Using IRS p6L4 MX5 M imagery the details of landscape/waterscape elements observed in the

estuarine belt as a whole (total waterspread area) are given in the Table 3.2.10. RS imageries of

1989, 2000, 2003 and 2010 depicting changes in land use in the Gangavali estuarine belt,

including 1 km buffer zone, are given in Table 3.2.11 and Figures 3.2.6 to 3.2.9 respectively.


53

Table 3.2.10: Details of area under tree mangroves (for 3 species), other vegetation, in the

total waterspread area in the estuary of Gangavali as per IRS p6L4 MX5 M imagery

Category LSE/WSE Area in ha % Rhizophora mucronata 3.010 0.46

Sonneratia alba 1.903 0.29 Avicennia_officinalis 2.088 0.32

Other vegetation 36.465 5.58 Open water 620.996 76.6

Estuarine fields 102.622 15.72 Plantations 6.693 1.03 Total area 817.1 ha

Figure 3.2.5: Gangavali estuary proper 2010 species-wise tree mangrove distribution based

on IRS p6L4 MX5 M imagery

Table 3.2.11: Changes in area under vegetation, waterspread area and fields in the estuary

of Gangavali (including 1 km buffer zone) during the year 1989, 2000, 2003 & 2010

Category

Year

Vegetation Water Fields ha % ha % ha %

1989 2280.827 48.77 715.264 15.29 1680.456 35.93 2000 2389.579 51.1 723.120 15.46 1563.847 33.44 2003 2348.34 50.22 783.664 16.76 1544.540 33.02 2010 2413.09 51.59 831.240 17.77 1432.240 30.64

Total area 4676.55 ha


54

Figure 3.2.6-3.2.9. Gangavali estuarine belt (including 1 km buffer zone): transitions in

landuse as observed in remote sensing imageries (1989-2010)

Figure 3.2.6 (L ) & 3.2.7 (R)

Figure 3.2.8 (L) and 3.2.9 (R)


55

B. MANGROVES OF AGHANASHINI ESTUARY

Figure 3.2.10: Aghanashini estuary showing mangroves, salinity zones and potential area

for planting

0 2.5 5

kilometres

Arabian S

ea

74.4

°E

14.5°N

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°E

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5°E

74.4

5°E

14.6°N

14.45°N

NH-17

Konkan Railway

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Konkan RailwayMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeriMadangeri

Heregutt iHeregutt iHeregutt iHeregutt iHeregutt iHeregutt iHeregutt iHeregutt iHeregutt iHeregutt iHereguttiHereguttiHereguttiHereguttiHeregutt iHeregutt iHeregutt iHeregutt iHeregutt iHereguttiHereguttiHereguttiHereguttiHereguttiHeregutti

MobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobraMobra

HolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagaddeHolanagadde

HalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkarHalkar

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KodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkaniKodkani

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AghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashiniAghanashini

KagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagalKagal

BaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaadBaad

HegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegdeHegde

ManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManakiManaki

DivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagiDivagi

KatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgalKatgal

BalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalaleBalale

GokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarnaGokarna

BARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGIBARGI

Kumta TownKumta TownKumta TownKumta TownKumta TownKumta TownKumta TownKumta TownKumta Town

LukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeriLukkeri

CHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVECHATRAKURVE

PADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANIPADUVANI

TORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKETORKE

NARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPURNARANAPUR

TOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANITOREGAZANI

Aghanashini Estuary

Village

Mangroves Potential Area

Mangroves

Index

High Salinity regionMedium Salinity regionLow Salinity region


56

The Aghanashini or Tadri river, 121 km long, originates at Manjuguni near Sirsi in Uttara

Kannada Western Ghats. It meets the tide at Uppinpatna in Kumta taluk. Elements of mangrove

vegetation begin here and increase in numbers and diversity for the next 24 km of the river’s

course. From the village of Mirjan, the river forms a vast expanse of backwaters or estuary that

runs parallel to the coast. This estuary is 13 km long and 2 to 6 km broad. The expansive and

shallow nature of the estuary and the presence of several mudflats make it ideal habitat for

mangroves. The river mouth at Tadri is narrow and situated between 2 hills of Gokarna and

Kagal villages.

Mangrove areas and potential areas for planting: Details of village-wise area under

mangroves and potential area for mangrove planting are shown in Table 3.2.13. Masurkurve 32

ha and Hiregutti with 23 ha have highest area under mangroves. Hireggutti has 151 ha suitable

area for mangrove planting followed by Madanageri with 128 ha. Details of area under high,

medium and low salinity areas with mangroves and available for planting are given in Table

3.2.12. With almost 733 ha of potential areas for planting Aghanashini estuary could developed

as one of the finest mangrove areas of Karnataka. Details regarding salinity zone-wise

recommended mangroves are given in Table 3.2.14. Studying site suitability we have also listed

mangrove associates for planting (Table 3.2.15)

Table 3.2.12: Salinity status-wise mangrove area and potential area for planting in Aghanashini estuary

Salinity level Mangrove area in ha

Potential area in ha.

Total waterspred area in ha.

High 29.25 675.3 2794

Medium 88.91 57.2 1910

Low 1.2 0 236.7 Total 119.36 732.5 4940.7


57

Table 3.2.13: Village-wise details of mangrove area and potential area available for planting in Aghanashini estuary

Sn Village Taluk Mangrove area (ha)

Potential area for planting (ha)

1 Aghanashini Kumta 0.41 2 Aigalkurve Kumta 1.29 1.21 3 Antravalli Kumta 1.08 4 Baad Kumta 6.47 6.28 5 Balale Kumta 0.04 8.92 6 Bargigazani Kumta 5.96 24.99

7 Betkuli Kumta 0.35 12.17 8 Chatrakurve Kumta 1.18 2.49 9 Divgi Kumta 1.39

10 Gudeangadi Kumta 0.94 1.71 11 Halkar Kumta 1.85 12 Hegde Kumta 4.36 1.59 13 Hiregutti Kumta 22.80 151.07 14 Hittalmakki Kumta 1.20 90.60 15 Hubbangeri Kumta 0.65 0.68 16 Kagal Kumta 4.66 17 Karkimakki Kumta 0.06 18 Kelagistala Kumta 4.10

19 Keppekurve Kumta 12.31 19.30 20 Kodkani Kumta 3.36 3.72 21 Kumta Kumta 0.29 22 Lukkeri Kumta 8.63 17.37 23 Madangeri Kumta 6.94 128.04 24 Manaki (r) Kumta 0.03 25 Manikatta Kumta 1.25 26 Masurkurve Kumta 32.29 8.19 27 Midlagazani Kumta 2.15 106.98 28 Mirjan Kumta 1.57 0.83 29 Morba Kumta 4.48 54.70 30 Nagerbail Kumta 2.72

31 Naranapur Kumta 3.86 32 Paduvani Kumta 2.58 33 Pattubele Kumta 19.33 13.05 34 Savalkurve Kumta 4.87 0.63 35 Tannirhonda Kumta 0.29 0.72 36 Toregazani Kumta 0.70 37 Torke Kumta 1.03 11.48 38 Yennemidi Kumta 2.62 75.46


58


Sn Mangroves sp. Salinity zones

High

Medium Low

1 Avicennia marina √

2 A. officinalis √ √

3 Excoecaria agallocha √ √

4 Kandelia candel √ √

5 Porteresia coarctata √

6 Rhizophora apiculata √

7 R.. mucronata √

8 Sonneratia alba √ √

9 S. caseolaris √

Table 3.2.15: Mangrove associates recommended for planting in suitable areas

1 Acacia nilotica

2 Anthocephalus kadamba (for low salinity edges only)

3 Barringtonia racemosa (for low salinity edges only)


5 Dolichandron spathacea

6 Erythrina indica

7 Ficus racemosa (Low salinity zone)


9 Pongamia pinnata

10 Salvadora persica (High salinity zone)

11 Thespesia populnea

Site-wise presence of mangroves and associates: Mangroves and mangrove associates were

studied in detail in about 18 sites. Their site-wise presence is given in Table 3.2.16. Of the tree

mangroves some of the most widespread are Rhizophora mucronata, Avicennia officinalis,

Sonneratia alba and Excoecaria agallocha.


59

Table 3.2.16: Distribution of mangroves and associates in different study locations of Aghanashini

Sn Name Locations 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

True mangroves 1 Acanthus

ilicifolius P P P P P P P P P

2 Acrostichum aureum

P P P

3 Aegiceras corniculatum

P P P

4 Avicennia marina

P P

5 A. officinalis P P P P P P P P P P P P 6 Excoecaria

agallocha P P P P P P P P P P

7 Kandelia candel

P P P P P P P P P P P P

8 Porteresia coarctata

P P

9 Rhizophora apiculata

P P P P P P P P

10 R. mucronata P P P P P P P P P P P P P 11 Sonneratia

caseolaris P P P

12 S. alba P P P P P P P P P P P Mangrove associates 13 Acacia nilotica P 14 Alstonia

scholaris P

15 Anthocephalus kadamba

P

16 Barringtonia racemosa

P

17 Caesalpinia crista

P P P P P P P P P P P


P P

19 Canavelia cathartica

P P

20 Capparis spp. P P P 21 Clerodendrum

inerme P P P P P P P P P P P P P P P P P P

22 Crateva magna P P 23 Cynadon

dactylon P P

24 Cyperaceae P P P


60

25 Cyperus malaccensis

P P

26 Derris scandens

P P P

27 D. trifoliata P P P P P P P P P P 28 Diospyros

embryopteris P


P P

30 Erythirna variegata

P P P P P P P

31 Ficus arnottiana

P P

32 F. racemosa P P 33 Flacourtia

sepiaria P

34 Ipomoea sp P P 35 Morinda

citrifolia P

36 Odina wodier P P P P 37 Pandanus

fascicularis P P P

38 Phyllanthus reticulata

P P P

39 Pongamia pinnata

P P P P P

40 Premna corymbosa

P P

41 Salvadora persica

P P P P P

42 Sapium insigne P P 43 Vitex negundo P P P 44 V. trifolia P 45 Zizyphus

mauritianus P

1. Gudikoppa; 2. Tudibele (planted patch); 3. Masurkurve; 4. Jeshtapura; 5. Kekkinkodi; 6. Keppekurve; 7.Bargi-gazni; 8. Kimmani-kodi; 9: Kimmani; 10. Paduvani; 11. Aigalkurve; 12. Mudangi; 13. Hoskatta; 14. Nushikote; 15. Morba; 16. Mankon; 17. Karkimakki; 18. Manaki


61

Notable localities studied for mangroves Gudikoppa: Situated in the Gudeangidi village this locality, an uninhabited island, has a

remnant patch of mangroves. Major part of island is used for shrimp farming. We studied the

linear mangrove patch using a belt transect of 50 m X 5 m. Alongside the natural patch has been

planted propagules of specially R. mucronata. The natural patch has A. officinalis, R.

mucronata, K. candel and S. alba in addition to the ubiquitous E. agallocha towards the bund.

K. candel constitutes 28% of the community followed by A. officinalis (26%), E. agallocha

(17%), R. mucronata (14%), and S. alba forming the rest. The shallow water meadows of Karki

fodder grass (Cyanodon dactylon) are seen in open areas. Villagers collect the grass during low

tides for fodder purpose. Notable of the several mangrove associates are D. trifoliata, C. crista,

Salvadora persica, Vitis trifolia, Capparis mooni etc. Gudeangidi village also has R. apiculata.

The extrapolated stem density/ha was 2720 and the estimated basal area/ha was 25.78m². This is

fairly good patch of mangroves worthy of conservation and enrichment.

Tudibele: A good patch of mangroves, is raised reportedly about 10-12 years ago. The main

species here are R. mucronata (71%), followed by S. alba (16%), K. candel (13%). The trees do

not exceed 50 cm in gbh. Although a close canopied patch there are some gaps created due to

occasional cutting by the people, as mangroves continue to form one of the sources of fuel.

Mangrove regeneration in the shade is poor, but for the saplings of K. candel here and there; S.

alba has good natural regeneration in open shallow habitats. The estimated trees/ha (10 cm &

above gbh), is 4301 and the basal area/ha is 13.31 m².

Masurkurve: This uninhabited island has a temple and a sacred grove dominated by old trees of

A. officinalis. The island also has several prawn farms, which were formerly fields for growing

Kagga rice. The trees are so old many of them have hollow stems, which make ideal habitats for

certain birds, particularly the Spotted Owlet. The small patch of mangrove, barely one ha in

extent, is so sacred no outsider is normally allowed to enter it. Although no tree is cut here dead

wood is sometimes extracted only for use as fuel in the temple. In the parlance of forestry this

patch may be described as “over-mature”. Birds are rich in and around this mangrove patch. In

the mid 1980’s the Centre for Ecological Sciences of Indian Institute of Science had attempted

mangrove afforestation at Masurkurve. Of the old natural growth here A. officinalis forms 68%,

the largest of them has a gbh of 160 cm and a height of about 12 m. Of the rest are R. mucronata

(18%), S. alba (6%) and K. candel (8%). The sacred forest has an estimated tree density of

678/ha and basal area of 43.86 m²/ha, by far the highest for any mangrove patch in Honavar

Forest Division.

Jeshtapura: Situated in Baad village this is part of the uninhabited Masurkurve island, also

dotted with prawn farms. A natural strip of fringe mangroves was surveyed here by using a belt


62

transect of 50X5 m. The dominant trees are R. mucronata and S. alba (37% each), followed by

A. officinalis (17%) and the rest consists of K. candel. Acanthus ilicifolius occurs gregariously

along the edges. E. agallocha is found along the drier edges. Of the mangrove associates are D.

trifoliata and C. crista. The estimated stem density (10 cm & above gbh)/ha is 1840 and the

basal area/ha is 24.82 m².

Kekkinkodi: This is in continuation of the Masurkurve island, falling within the Hubbankeri

village. The locality is rich in regenerating and planted mangroves. Regeneration is more ever-

since some of the prawn farms have been abandoned due to the losses suffered by the owners. R.

mucronata planted eight years ago is growing up well. S. alba grows naturally in all suitable

localities. The others are K. candel, E. agallocha, Aegiceras corniculatum, and A. officinalis.

Further ahead, part of the island facing Baad village has R. apiculata. Probably the higher

salinity favours its growth. In the Muligajni part, on the bund, are bushes of S. persica and

Ipomoea sp.

Keppekurve: This is also part of the Masurkurve island, further towards the sea. Of the

mangroves fringing the river are R. apiculata, R. mucronata, E. agallocha, A. corniculatum, K.

candel and A. ilicifolius. There are several trees of A. marina as well as R. apiculata. Of the

notable mangrove associates are the tree Morinda citrifolia and the bushy medicinal plant S.

persica.

Bargi-gazni: Part of an island known as Chowlikurve (falling within the Kimmani village of

Hiregutti Forest Range) has very densely planted saplings of particularly Rhizophora. The

number approaches almost 8/m²; that is almost 80,000/ha. The officer in charge stated that such

dense planting was attempted, throughout his jurisdiction, due to the following reasons:

The casualties were heavy in previous plantings due to 1. Lack of awareness on the

importance of mangroves among the locals, who considered them more as a hindrance to

boat landing and casting of nets. However, they are developing more positive attitude

towards mangroves. 2. Many did not associate mangroves with fish productivity;

however, this attitude also is changing due to greater awareness. 3. The buffaloes were

found to feed on foliage, and damage was found to be more in saplings. 4. The barbed

wires used for protecting the planted patches hardly last beyond 2 or 3 months due to the

corroding influence of salt water.

The vigilance by forest watch and ward staff facilitated high percentage of survival. It

will be of interest to monitor constantly the growth patterns and overall impact on the

ecosystem of these dense patches of upcoming mangroves all over the estuary,

particularly in the jurisdiction of Hiregutti Range. The lessons to be learnt need to be


63

chronicled so as to benefit the future managers of mangroves throughout the Honavar

Division.

In rest of the Bargi-gazni the mangroves are R. apiculata (several trees), R. mucronata, S.

alba, A. officinalis, E. agallocha, A. ilicifolius etc. Bargi-gazni has a mangrove nursery in

which many species were raised. The officer in charge could prepare a nursery manual

narrating his experiences and providing instructions and sketches on successful mangrove

raising, that will be of tremendous use to the posterity.

Kimmani-kodi: This is a narrow natural tidal channel passing alongside the swampy

Savalkurve, along which occur natural mangroves and densely planted and protected linear strips

of mangrove saplings. R. apiculata is notable among the natural mangroves. Most of the planted

propagules are one-year old R. mucronata. Occasionally found are S. alba.

Kimmani: Here natural growth of R. apiculata is found in addition to S. alba, A. officinalis, E.

agallocha etc. Some mangroves were raised here over a decade ago by Ibrahim Upparkar, a

farmer and aqua-culturist, to protect his gazni from breaching. He set an example how farmers

could take lead role in mangrove afforestation, an activity that needs encouragement from the

State.

Paduvani: Fringing the gajni bund are seen natural populations of R. apiculata and S. alba.

Densely planted mangroves were noticed near Chowlikurve. Pongamia pinnata, Alstonia

scholaris, Erythrina variegata, Odina wodier and C. crista are mangrove associates.

Aigalkurve: This is a densely populated island having poor growth of fringe mangroves

alongside. Occasional individuals of A. officinalis, K. candel and R. mucronata are found. Open

shallow waters have meadows of the grass P. coarctata.

Mudangi: This locality, close to the salt-pans of Sanikatta and alongside the road to Tadri is

notable for old mangrove trees alongside the gazni bund. The trees belong to R. mucronata, R.

apiculata, A. officinalis, A. marina K. candel and S. alba. E. agallocha. A. corniculatum and A.

ilicifolius are other mangroves. Non-mangroves have high diversity due to the habitat

heterogeneity brought in by the steeply rising hill alongside. Notable are Premna corymbosa,

Ficus arnottiana, Odina wodier, Capparis moonii, Ipomoea sp., Phoenix sp. and D. trifoliata.

Shell mining and transportation cause some disturbances in the habitat.

Hoskatta: This locality seems to have had good mangrove growth in the past. Due to the salt

pans and shell mining and transportation mangrove habitat is qualitatively altered. Instead of soft

mud the soil is overlaid with shell fragments and other rough particles. The mangroves here do


64

not have any regeneration. Old trees of R. mucronata are found here. In shallow marshes cut off

by roads could be seen A. officinalis and A. ilicifolius.

Nushikotte: The shallow backwaters of this locality were used for salt manufacture by Ballarpur

Industries at Binaga, and subsequently salt production was abandoned. In this barren expanse of

water the Forest Department, since last 8-10 years has been raising mangroves extensively and

with protection. In the coming years there is every likelihood of this locality getting transformed

into a biodiverse and productive mangrove ecosystem.

Moraba: Fringe mangroves in low density occur here; notable species are A. officinalis, S. alba

and A. ilicifolius. E. agallocha grows well on the bunds. Well-distanced planted saplings of R.

mucronata and K. candel are also found. Mangrove associates are C. crista, Derris scandens, D.

trifoliata, S. persica, Acacia farnesiana, Zizyphus mauritiana, Capparis spp. etc.

Mankon: In this locality towards the east of the National Highway bridge, the river is narrower

and salinity lower. The increased mixing of fresh water makes this place less suitable for true

mangroves. Mangroves with greater tolerance of fresh water, like S. caseolaris and K. candel

occur in such places. The fern A. aureum has healthy growth alongside the river below the lush

greenery of household gardens. We came across newer mangrove associates such as Crateva

magna, Diospyros embryopteris and Anthocephalus kadamba in addition to the usual ones such

as Pongamia pinnata, Pandanus fascicularis, C. crista, F. racemosa etc. Cyperus malaccensis is

quite common along shallow edges. There is not much scope for raising mangroves here due to

the narrowness o h river.

Karkimakki: Here too salinity is lower and the only mangroves found are occasional K. candel

and S. caseolaris and A. aureum. The mangrove associates found are as in Mankon; additionally

was noted Barringtonia racemosa. Cynodon dactylon grows underwater at shallow depth.

Manaki: This village situated towards the National Highway Bridge towards the south bank of

the river. Mangroves are very rare and of the fringe type. A. ilicifolius, A. offcinalis, S.

caseolaris, E. agallocha and K. candel are the notable mangroves.

Spatial extent assessment of mangroves in Aghnashini using remote sensing data

Using RS data from 2410 IRS p6L4 MX5 M we could estimate the area under the three

dominant tree mangroves namely Avicennia officinalis, Rhizophora mucronata and Sonneratia

alba alongwith other landscape/waterscpe elements (Table 3.2.17 for details). The interpreted

imagery is given in Figure


65

Table 3.2.17: Aghnashini estuary proper: area under individual tree mangroves (for 3 species only) and other landscape/waterscape elements as deciphered from 2410 IRS p6L4 MX5 M imagery

Category HA %

Rhizophora mucronata 74.27 1.42

Sonneratia alba 33.72 0.65

Avicennia officinalis 5.40 0.11

Vegetation 857.46 16.37

Water 3615.19 69.05

Open fields 259.13 4.94

Bund 390.83 7.46

Total area 5236.00

Figure 3.2.11: Aghnashini estuary proper, including islands, showing tree mangroves,

bunds, other vegetation, fields and waterspread area


66

Figure. 3.2.12-15: Remote sensing imageries showing area under vegetation, water and

open fields in the Aghanashini estuarine belt (including one km buffer zone)

Figure 3.2.12 (L) & 3.2.13 (R)

Figure 3.2.14 & 3.2.15


67

Details of area in ha under vegetation, water and open fields, including for 1 km buffer zone, are

shown in Table 3.2.18. Part of the increase in area under vegetation in 2010 is due to increase in

mangroves.

Table 3.2.18. Remote sensing data analysis for 1989, 2000, 2003 and 2010 for major

landscape/waterscape elements for Aghanashini estuary, including 1 km buffer zone

Year

Vegetation Water Open fields

HA % HA % HA %

1989 5675.238 40.79 2643.525 19 5595.85 40.22

2000 5483.632 39.41 2622.254 18.85 5808.728 41.75

2003 5435.506 39.06 3988.784 28.67 4490.323 32.27 2010 6250.39 44.92 3148 22.62 4516.21 32.46

Total area 13914.614


68

C. MANGROVES OF SHARAVATHI -BADGANI ESTUARINE COMPLEX

The Sharavathi or Gersoppa River has its origin at Ambutirtha in Thirthalli taluk of Shimoga

District. After a northerly course of about 64 km from Nagar, it forms the south-east boundary of

Uttara Kannada for about 13 km and then passes about 32 km west covering a total distance of

128 km in all to join the sea at Honavar. Soon after touching the border of Uttara Kannada

district, the river water hurtles down vertically from a precipice of 252 m in to a pool 117 meters

deep forming the famous Jog falls. About 30 km west, it reaches the ancient capital of Gersoppa.

During the remaining 27 km to the coast, the river flows between richly wooded banks fringed

with mangrove bushes. It was a broad tidal estuary with brackish water in the dry weather. But

the execution of Linganmakki and Gersoppa dams for power generation found salinity conditions

approaching almost fresh water conditions throughout the year, causing most high and medium

salinity tolerant mangrove species vanishing from the estuary, leaving behind only those which

can live in low brackish conditions.

About eight km from mouth, the river widens to a lagoon about three km broad, containing a few

islands, the longest being Mavinkurve which is more than five km long with a large area of

paddy lands and studded with mango and coconut. For about 2 km from the mouth, the river has

a breadth of about 1.5 km. At the mouth, again it narrows into a channel about 275 meters broad.

Outside of it lies a formidable and changing sand bar. The village Pavinakurve at its mouth near

Honavar has been nearly washed off recently and the river has been depositing sand at Kasarkod

on the left bank of its mouth.Sharavathi has an estuarine spread of approximately 27 kms.

Details regarding mangrove area and and area suitable for planting and their village-wise

distribution are given in Table 3.2.19. Total area under mangroves in the Sharavathi part of

estuary was estimated was 54.01 ha. Total potential area for mangrove planting was 124.7 ha.

The Badgani estuary that merges with Sharavathi towards its opening in the Arabian Sea, salinity

is higher, but being a small creek like area the mangroves are in small fragments (16.4 ha) and

the potential area is also lesser (55 ha). Sharavathi-Badgani estuarine complex has a total

waterspread area of 2695.8 ha.


69

Table 3.2.19: Village-wise mangrove area and area suitable for planting in Sharavathi-Badgani estuarine complex

Sn Village Taluk Mangrove area

(ha) Potential area for

planting (ha) 1 Berolli Honavar 3.15 2 Hadinbal Honavar 0.37 3 Haldipur Honavar 10.27 22.22 4 Honnavar Honavar 8.43 2.67 5 Hosad Honavar 2.02 6 Hospattan Honavar 21.57 6.98 7 Jalwal-karki Honavar 1.59 8 Kadtoka Honavar 0.57 9 Kakurve Honavar 0.43 4.66

10 Kankichitta Honavar 0.64 11 Karki Honavar 8.44 14.54 12 Kasarkod Honavar 20.74 67.59 13 Kelginoor Honavar 0.77 14 Kharwa Honavar 0.20 15 Kulkod Honavar 1.96 16 Mavinkurve Honavar 32.02 39.83 17 Melin-idgunji Honavar 1.30 18 Molkod Honavar 1.09 5.65 19 Mugwa Honavar 2.55 20 Navilgone Honavar 1.83 12.79 21 Padukuli Honavar 0.13 0.29 22 Pavinkurve Honavar 0.84 0.62 23 Harnir Kumta 0.29 0.05 24 Holegadde Kumta 2.32 15.41 25 Horbhag Kumta 0.23 4.89 26 Konalli Kumta 1.14 27 Madgeri Kumta 9.35 0.79 28 Talgod Kumta 0.26 1.35 29 Urkeri Kumta 3.19 8.17


70

Salinity decline in Sharavathi

Most of Sharavathi estuary has uniformly low salinity, dipping down to 0.5 ppt or less many

times, making conditions difficult for high and medium salinity requiring mangroves. Low

salinity mangrove tree Soinneratia caseolaris flourishes in the estuary. Lowered salinity due to

hydel projects has caused extinction of most high salinity tolerant species from Sharavathi part of

estuary. Details of mangroves recommended for planting in the different salinity zones are given

in Table 3.2.20. Mangrove associates recommended for planting are in Table 3.2.21.


Sl.No. Mangroves sp. Medium salinity

zone* Low salinity

zone

2 A. officinalis √

3 Excoecaria agallocha √

4 Kandelia candel √ √

5 Sonneratia alba √ √

6 R. mucronata √

7 S. caseolaris √ *5-10 ppt Table 3.2.21: Mangrove associates recommended for planting in suitable areas

1 Barringtonia racemosa (In low salinity creeks only)


3 Cerbera manghas


5 Erythrina indica

6 Ficus racemosa


8 Pongamia pinnata

9 Ficus racemosa (Low salinity zone)


71

Details of mangroves and associates: site-wise Some localities in Sharavathi estuary were studied for mangroves in details (Table 3.2.22). Most

widespread mangrove tree is the low salinity tolerant Sonneratia caseolaris, followed to a lesser

extent by Kandelia candel. May be due to lowered salinity in the estuary the mangrove

associates were prolifically growing in many localities. In Table 3.2.23 a list is furnished.

Table 3.2.22: Location-wise distribution of mangroves in Sharavathi estuary Sn Name Island

-1 Kasar- kod

Kalsana- motte

Hosa-patan

Mulkod Mavin-kurve

Kulkod creek

1 Acanthus ilicifolius P P P 2 Acrostichum

aureum P P P

3 Avicennia officinalis P P 4 Excoecari

agallocha P P

5 Kandelia candel P P P P 6 R. mucronata P P* 7 Sonneratia alba P 8 S. caseolaris N P P P P P P P: Present; P* Planted saplings Table 3.2.23: Location-wise distribution of mangrove associates in Sharavati estuary

Sn Name Kalsana- motte

Hosa-patan

Mulkod Island

Devan- motte island

Kulkod creek

1 Barringtonia racemosa √ √ 2 Caesalpinia crista √ √ √ √ 3 Calophyllum inophyllum √ √ C. malaccensis √ √ √ √ √ 4 Cerbera manghas √ √ √ √ √ 5 C. inerme √ 6 Derris canarensis √ 7 Derris scandens √ √ 8 Derris trifoliata √ 9 Dolichandron spathacea √ √ 10 Erythrina indica √ 11 Ipomoea fistulosa √ 12 Pandanus fascicularis √ √ √ √ 13 Pongamia pinnata √ √ 14 Premna corymbosa √ √ √


72

15 Sapium insigne 16 Thespesia populnea √ 17 Vitex negundo √

Locality-wise details: Sharavathi

Island-1: This small uninhabited island situated midway between the bridges of national

highway and the railway is due to accretion of materials, and is hardly above water level. The

island is fully covered with low mangroves and has abundance of the sedge Cyperus

malaccensis. Small trees or saplings of Rhizophora mucronata, Kandelia candel, Sonneretia alba

are found here. Acanthus ilicifolius grows plentifully.

Kasarkod: Adjoining the tile factory of Kasarkod is a good patch of mangroves. This includes a

planted patch of R. mucronata, where most individuals are 2 to 2.5 m in height. Another is

almost a pure patch of Sonneretia caseolaris, which stands well the influx of fresh water

throughout. The trees have heights ranging from 4-7 m. Our sample survey shows the Kasarkod

patch of mangroves has stem density of 2188/ha and basal area of 13.43 sq.m.

Kalsanamotte: This is a small island, one side of which is inhabited. S. caseolaris thrives well

here fringing the borders of the island. The mangrove fern Acrostichum aureum, Cyperus

malaccensis and Kandelia candel are also found here. Notable of the mangrove associates are

Calophyllum inophyllum, Caesalpinia crista, Clerodendron inerme, Cerbera manghas and

Pandanus fascicularis. This place is somewhat unique in the Honavar Forest Division in having

some trees of Thespesia populnea, rarely found elsewhere.

Hosapatan: The river bank is fringed with isolated individuals of S. caseolaris and K. candel.

A. ilicifolius and C. malaccensis are found all over the edges. Of the mangrove associates are C.

manghas and P. fascicularis.

Mulkod island: The river is almost fresh water here and very few mangroves are still seen here.

These are S. caseolaris, E. agallocha and A. ilicifolius. Excoecaria agallocha are all older

individuals without any regeneration. A. aureum is also found in moderate numbers. The island

is rich in mangrove associates like C. manghas, Derris spp. and P. fascicularis. Rarely found are

Barringtonia racemosa, Dolichondron spathacea, Calophyllum inophyllum and C. crista.

Devanmotte island: Fringing the island all along are S. caseolaris. Cyperus malaccensis is also

common. Mangrove associates are many such as C. inophyllum,C. crista, C. manghas, C.

inerme, P. fascicularis and Vitex negundo.


73

Mavinkurve island: The island is surrounded by S. caseolaris, which attain fairly big heights

ranging from 13 to 16 m; these are presently candidates for tallest mangroves of the Honavar

Division. The local residents informed us that many of these trees are planted by them in their

own lands, about 20 years ago. Extrapolating tree density for one ha the stem count could be

1600/ha, and the estimated basal area 60.21 sq. m/ha. Though this is not the real situation, the

estimate clearly shows that Sharavati river fringes (including tidal edges of islands) are highly

suitable for raising plantations of, particularly S. caseolaris. The basal area estimate of 60.21

sq.m/ha is as good as the best forest patch in Uttara Kannada district. The farmers can at least

partly meet their biomass needs through mangroves, while they also enhance productivity and

biodiversity of ecosystem as well as afford protection from natural calamities.

Kulkod creek: On the sides of this creek are many mature trees of A. officinalis. Sonneratia

caseolaris is also frequent. E. agallocha is occasionally found. There is plentiful growth of A.

aureum and A. ilicifolius and C. malaccensis. Of the mangrove associates may be mentioned B.

racemosa, C. manghas, D. trifoliate, D. spathacea, Erythrina indica, Pandanus fascicularis, P.

pinnata, Premna corymbosa etc.


74

Factors affecting mangrove community The stone embankments on both sides of the river in most places do not favour the growth of

mangroves. The islands are better places for some of the mangroves, and with some amount of

awareness creation these islands can be shielded with mangroves, notably by S. caseolaris.

Constant release of fresh water from hydel projects in the river and the formidable sandbar

blocking most of the river mouth have made Sharavathi estuary almost into a fresh water lake.

Few are the mangroves which can survive in this situation. In many places the residents along

the river banks have extended their gardens right into the river by building compound walls.

Badgani estuary Table 3.2.24: Location-wise distribution of mangroves in Badgani creek Sl no

Name Pavinkurve Taarebagilu Badgani bridge

1 Avicennia officinalis P P 2 Rhizophora mucronata** P P 3 Kandelia candel P P P 4 Sonneratia caseolaris♠ P 5 Acanthus ilicifolius P P P 6 Aegiceras corniculatum P P 7 Excoecaria agallocha P P ♠Only single tree noted; ** Seedlings noted; P : present Pavinkurve: This village, is situated close to the mouth of Badgani. The seashore of Pavinkurve

is very vulnerable to sea erosion during the rainy season. The estuarine mouth is bunded with

granite rocks and has hardly any scope for growth of mangroves. However, the estuarine part has

very good potential for mangrove regeneration. Most of the low-lying areas, alongside the

estuary, formerly fields of rice, are today shrimp farms. Mangroves appear to have suffered

badly due to human impact, in the recent years. Big trees are very scanty. The creek has saplings

of R. mucronata, A. officinalis, A. corniculata and E. agallocha. Pavinkurve is notable for large

number of mangrove shrub A. corniculatum. The shrubby A. ilicifolius forms in many places

impenetrable patches. Of late prawn farming is declining due to rainy season flooding and

increased incidence of prawn diseases.

Tarebagilu: Acanthus ilicifolius is the most dominating formation of mangroves. Trees are

scanty due to human disturbances. The areas adjoining have been converted into shrimp farms.

Some trees of A. officinalis could be seen in the area.

Badgani bridge: Close to this bridge on the national high way, the Forest Department has

recently planted several seedlings of R. mucronata. The habitat is not all that good at this region


75

for mangroves, due to various human disturbances. These include fishermen casting nets and

grazing and trampling by livestock, particularly by buffaloes. Most lands, otherwise suitable for

mangroves, has been converted into aquaculture ponds or shell-mining areas. Some small bits of

mangroves left, being sacred spots to the locals, few mangrove trees are left. These are E.

agallocha, K. candel and A. corniculatum. A. ilicifolius is common within the estuary as well as

in water-logged abandoned rice fields alongside.

Remote sensing for mangrove species/land cover-land-use prospecting

Using remote sensing imagery from 2410 IRS p6L4 MX5 M it was possible to make an

assessment of area under tree mangrove species and other waterscape/landscape elements in the

Sharavathi-Badgani estuarine complex proper as shown in the Table 3.2.25

Table 3.2.25: Area estimates under tree mangroves and other waterscape/landscape

elements in Sharavathi-Badgani estuarine complex proper using 2410 IRS p6L4 MX5 M

imagery

Category Ha %

Avicennia officinalis 10.70 0.31

Sonneratia alba 23.00 0.67

Kandelia candel 6.81 0.20

Rhizophora mucronata 5.41 0.16

Sonneratia caseolaris 81.96 2.40

Plantations 219.65 6.44 Vegetation 515.21 15.08 Water 1334.90 39.08 Open space 1218.12 35.66

Total area 3415.75


76

Figure 3.2.16. 2010 IRS p6 L4 MX 5M imagery of Sharavathi-Badgani estuarine complex

proper showing distribution of tree mangroves (4 species), waterscape area, plantations,

fields etc.


77

Figures 3.2.17-20. RS images of 1989, 2000, 2003 and 2010 of Sharavathi-Badgani estuarine

complex including of 1 km buffer zone

Figures 3.2.17 (L) & 18 (R)

Figures 3.2.19 (L) & 20 (R)

Landuse landcover changes as evident from RS imageries

Details of changes in landuse/landcover, waterscape area in the Sharavathi-Badgani estuarine

complex, including 1 km wide buffer zone, using remote sensing data, for the years 1989, 2000,

2003 and 2010 are given in Table 3.2.26

Table 3.2.26: Transitions in landuse-landcover during 1989-2010 period as seen from RS

imageries (includes also 1 km buffer zone)

Category

Year

Vegetation Water Open fields

Ha % Ha % Ha %

1989 11111.373 59.7 2237.259 12.02 5263.123 28.28 2000 11049.269 59.37 2264.911 12.17 5297.575 28.46 2003 11076.469 59.51 2046.437 11 5488.849 29.49 2010 11258.783 60.49 2497.855 13.42 4855.117 26.09

Total area 18611.75


78

D. MANGROVES OF VENKTAPUR RIVER The Venktapur River rises in the Western Ghats near the village Kanti towards the north-east

corner of Bhatkal. It joins the Arabian Sea at Venktapur towards the north of Bhatkal town. The

river, for the last 5 km forms a tidal estuary where occur the mangroves (Figure 3.2.21). The

first organized efforts to study the mangroves of Venktapur were made by Ananda Rao and

Suresh (2001). Notably we could not collect Avicennia alba, which was rather widespread

according to Rao and Suresh (2001). Whereas Sonneretia alba has widespread distribution in our

study the same was not reported by Rao and Suresh (2001). The true mangroves recorded by

these authors village-wise are given in Table 3.2.27. Table 3.2.28 contains details of true

mangroves recorded by Rao and Suresh (2001) and in the present study. We could not locate

Avicennia alba which was reported by earlier authors. Venktapur estuary is the only place in

Honavar Forest Division having rare presence of Bruguiera gymnorrhiza. Details of location-

wise mangroves and associates are given in Table 3.2.29.

Figure 3.2.21. Venkatapur estuary showing mangrove areas and potential areas


79

Table 3.2.27: Village-wise details of mangrove area and potential area available for planting in Venktatpur estuary

Sn Village Taluk Mangrove area in ha.

Potential area available for planting (ha)

1 Bengre Bhatkal 1.478 1.433

2 Heble Bhatkal 2.801 7.187

3 Kaikini Bhatkal 2.497

4 Shirali Bhatkal 10.495 16.300

5 Venktapur Bhatkal 3.308 1.911 Table 3.2.28: Mangroves of Venktapur reported by Rao and Suresh (2001) and in the present study Sn Name of mangrove Rao & Suresh (2002) Present study 1 Avicennia alba P Unconfirmed 2 A. officinalis P P 3 A. marina N P 4 Aegiceras corniculatum P N 5 Excoecaria agallocha P P 6 Sonneratia alba N P 7 S. caseolaris P P (rare) 8 R. mucronata P P 9 Kandelia candel P P 10 Bruguiera gymnorrhiza P P (rare) 11 Acanthus ilicifolius P P 12 Acrostichum aureum P P 13 Cyperus sp. P P Note: P : present; N : Not found. Table 3.2.29: Location-wise distribution of mangroves & mangrove associate species Sn Mangroves

Heb

le

Mog

erke

ri

Alv

ekod

i

Kur

igad

de

Heg

le

Mul

lana

keri

Kan

data

hitl

Mangroves Acanthus ilicifolius + + + + + +

Acrostichum aureum + Aegiceras corniculatum Avicennia marina + + + Avicennia officinalis + + + + + +

Brugiera gymnorrhiza + + + + + Cerbera odollum +


80

Excoecaria agallocha + + + + + + Kandelia kandel + + + +

Porteresia coractata Rhizophora mucronata + + + + + + Sonneratia caseolaris + Sonneretia alba + + + Mangrove associates Caesalpinia crista + Caeslpinia nuga + Calophyllum inophyllum + Clerodendron inerme + + + + Cuscuta spp. + Derris trifoliate + + + Erythrina indica + + Pandanus sp. + Premna corymbosa + + + Heble: Heble has small promising patches of mangroves. The soft, muddy soil is favourable for

mangrove growth. According to local informants the mangroves suffered major setback due to

clearance for prawn farming. Sometimes they are cut for fuel and poles. Subsequently they were

allowed to grow and what present now are mostly coppice shoots. The owners of the land

presently believe that the mangroves can give protection from strong winds. The tree community

sampled is composed of 70% S. alba, 28% of A. offficinalis and 2% R. mucronata. Some

saplings of the rare mangrove Bruguiera gymnorrhiza are also found. There are some coppicing

individuals of A. marina. E. agallocha occurred along the edges. A. ilicifolius is common.

Mogerkeri: Fringing the creek are isolated trees and bushes of mangroves such as: R.

mucronata, A. officinalis, A. ilicifolius and E. agallocha, There are also R. mucronata planted

along the bank, in the recent years by the Forest Department. The survival of the planted

mangroves is not satisfactory. The mangrove associates are C. inerme, D. trifoliata, Caesalpinia

nuga, Premna serratifolia, Erythrina indica etc.

Alvekodi: This place has linear formation of mangroves along the fringes. The species found are

Avicennia marina, A. officinalis, Excoecaria agallocha and Acanthus ilicifolius. Rarely found are

Sonneretia alba. Avicennia marina consists of mostly coppicing plants. The mangroves are under

high degree of human impacts. Near the bridge the Forest Department has planted Rhizophora

mucronata. Notable of the mangrove associates are Erythrina indica, Premna corymbosa,

Clerodendrum inerme and Derris trifoliata etc. More upstream in the creek are Cerbera

odollum, Pandanus fascicularis and C. inophyllum.


81

Kurigadde: This is a small island in the river. The island was reportedly under paddy cultivation

once, but now it is in abandoned state. The island is colonized by A. ilicifolius, A. officinalis, S.

alba and E. agallocha. Sedge grass (Fam: Cyperaceae) is found along the edges. E. indica, C.

inerme are notable mangrove associates.

Hegle: A opportunistic survey carried out for a distance of 2 km from Venktapur river bridge to

Hegle. In this belt of estuary are found A. ilicifolius, A. officinalis, E. agallocha, K. candel,

Rhizophora mucronata, and the fern A. aureum. Near the hamlet of Hegle, occurs one tree each

of Sonneretia caseolaris and Bruguiera gymnorrhiza, the latter is the rarest species in the

Honavar Forest Division. Occasionally found are planted saplings of R. mucronata. Along the

edges of the creek are mangrove associates C. crista, D. trifoliata, P. corymbosa and C. inerme.

Doddar, a yellow coloured, wiry, leafless parasitic creeper is found on some of the bushes.

Mullanakeri: Here about 300 m² is covered with dense growth of A. ilicifolius and coppicing

bushes of A. marina. This is a potential patch for mangrove restoration. Another 200m² is also

covered with A. ilicifolius and saplings of K. candel. Bruguiera gymnorrhiza and A. officinalis

were also are present. Nearby was noted 17 saplings of R. mucronata planted by the

Department. Perhaps many saplings of the species did not survive here. Another 600m² presently

covered with A. ilicifolius is a potential area for mangrove restoration. Kantadahitlu in the creek

has also some mangroves. Dense patches of the spinous undershrub A. ilicifolius has covered

many parts of the creek. Within these patches of Kantadahitlu natural regeneration of A.

officinalis and K. candel can be observed.

Applications of remote sensing for mangrove mapping for 1989-2010 period Using RS data of 1989-2010 period overall vegetation cover increase was noticed; it is difficult to tell whether there was any increase in mangroves (Table 3.2.30-31; Figures 3.2.22) Table 3.2.30. Venkatapur estuary proper: area under individual tree mangroves (for 3 species only) and other landscape/waterscape elements as deciphered from 2010 IRS p6L4 MX5 M imagery

Category HA % Avicennia officinalis 9.928 4.53 Sonneratia caseolaris 0.711 0.32 Sonneretia alba 5.636 2.57 Vegitation 56.545 25.81 Open fields 70.933 32.38 Water 75.336 34.39

Total area 219.089


82

Figure 3.2.22: Venkatapur estuary proper, including islands, showing tree mangroves,

bunds, other vegetation, fields and waterspread area

Table 3.2.31: Changes in details on area under vegetation, water and fields based on RS imageries (1989-2010)- includes 1 km buffer zone also-

Vegetation Water Fields Ha % Ha % Ha %

1989 226.17 28.2 87.84 10.95 488.07 60.85 2000 243.54 30.36 84.87 10.58 473.67 59.06 2003 269.36 33.58 55.98 6.98 476.74 59.44 2010 272.33 33.95 125.36 15.63 404.39 50.42

Total area 802.08


83

Figures 3.2.23-26: RS images of 1989, 2000, 2003 and 2010 of Venkatapur estuary including of 1 km buffer zone

Figures 3.2.23 (up L) & 24 (up R); 25(down L) & 26 (down R)


84

E. ALVEKODI CREEK

This is the only notable creek in the division with mangroves. The others are smaller ones and

dealt with as part of the estuaries with which they are linked. Alvekodi creek is towards the

mouth of a small stream in Kumta. The old town of Kumta is situated on its north bank. The

creek had in the past seen considerable trade especially in cotton, spices and various other

products. Ever-since Bomaby-Hubli rail link was made the trade vanished. Today it only serves

the transport of fish by small boats from the sea to the Kumta fish market. Details regarding

mangrove areas and potential areas are given in Table 3.2.32-33 and Figure 3.2.27

Table 3.2.32: Kumta creek proper: area under mangroves and potential area

Figure 3.2.27: Kumta creek proper, mangroves, Potential area and waterspread area

Category Area in ha

Potential 42.4

Mangrove 14.2 Total water spread 238.1


85

Table 3.2.33: Village-wise mangrove area and area suitable for planting in Kumta creek

Sn Village Taluk Mangrove area (ha)

Potential area for planting (ha)

1 Kalbhag Kumta 6.32 3.71 2 Kumta Town Kumta 7.71 36.09 Total 14.03 39.80

Status of mangroves At one time the creek with shallow water and mud-flats must have been full of mangroves. In

due course the low lands alongside have been reclaimed for cultivation, salt making and human

settlement. In the recent times the wetlands alongside have been embanked for prawn farming.

The details of mangroves in the estuary are given below. In the recent years good efforts at

mangrove afforestation have been made by the Forest Department. Mangroves have been studied

at Honmav, near fish market, Sasihitlu and Devgundi.

Honmav: Good growth of natural mangroves of low height occurs between NH bridge and the

fish market bridge. The estuary bed is full of boulders covered with oyster shells. Dense patches

of dwarf mangroves of species such as A. officinalis, A. marina, R. mucronata and S. alba are

found here. There are also K. candel, E. agallocha and A. ilicifolius. Towards the upstream,

eastwards of the NH bridge are found plantations dominated by R. mucronata in excellent

growth. Of the mangrove associates are Clerodendron inerme, Derris trifoliata, Caesalpinia

bonducella etc.

Devagundi: Further upstream along the creek the mangroves almost come to an end here. Only

species found here are A. officinalis and E. agallocha. Most of these are coppices and are

subjected to much hacking. Prawn farms without any traces of plant growth exist all along the

sides of the creek.

Near fish market: Near the fish market of Kumta the creek is dominated by A. officinalis, A.

marina and A. ilicifolius.

Sasihitlu: This part of the creek, almost up to its mouth is an area subjected to much

anthropogenic pressures. The mangroves found here are A. officinalis, A. marina, R. mucronata,

K. candel, S. alba and E. agallocha. Stream bank has narrow stretch of land suitable for

mangrove afforestation. Common mangrove associates are C. inerme, D. trifoliata and

E.variegata.


86

3.3. MANGROVE SITUATION: RANGEWISE

Mangroves of Bhatkal forest range

Bhatkal range in the southernmost part of Honavar forest division (74°29’33.324” to

74°40’41.7792 E long. and 13°55’27.9192 to 14°7’49.512 N lat.) and extends over an area of

27,990 ha (16.47% division). Range has its headquarters in Bhatkal town and covers 61 revenue

villages of Bhatkal taluka are under its jurisdiction. Range is administratively divided in to 5

forest section and 15 beats (Figure 3.3.1). Range is having 73.99 percent of forest area; most

forests are basically evergreen. The coastline is 23.84 km. long and includes an island. Major

estuary is Venkatapur, (184.6ha). It has small creeks namely Jali creek (7.53h) and Bhatkal

creek (45.43 h) Mundalli creek, Hadeen creek and Belke creek (10 h). Mangroves are found

mainly in Shirali beat of Shirali section, Bhatkal beat of Bhatkal section; and very little areas

Hadeen and Belke beats of Belke section. Beat wise detail mangrove area, species and potential

area are given in Figures (3.3.2-3.3.3)

Figure 3.3.1: Administrative map of Bhatkal Forest Range


87

Figure 3.3.2: SHIRALI BEAT Beat Area (ha) 3931 No. of mangrove patches

125

Mangrove area (ha)

10.79

Perimeter in km

33.90

No. of potential areas for planting

19

Total area for planting (ha)

14.089

Dominant species

Rhizophora mucronata, Avicennia marina, Bruguiera gymnorrhiza, Kandelia candel, Avicennia officinalis, Excoecaria agallocha, Sonneratia alba, Rhizophora apiculata, Acanthus ilicifolius

Recommended Species

Avicennia marina, Rhizophora mucronata, Bruguiera gymnorrhiza, Acanthus ilicifolius, Sonneratia alba, Avicennia_officinalis,

Estuary Venkatapur Taluk Bhatkal


88

Figure 3.3.3: BHATKAL BEAT

Beat Area (ha) 4538 No. of mangrove patches 103 Mangrove area (ha) 25.39 Perimeter_KM 25.39 No. of potential areas for planting 21 Total area for planting (ha) 8.676

Dominant Species

Avicennia officinalis, Bruguiera gymnorrhiza, Acanthus ilicifolius, Excoecaria agallocha, Sonneratia alba

Recommended Species

Avicennia officinalis, Excoecaria agallocha, Bruguiera gymnorrhiza, Sonneratia alba

Rivers/creek Venkatapur, Bhatkal creek, Jali creek

Taluk Bhatkal


89

Mangroves of Manki Range

Figure 3.3.4: Administrative map of Manki Forest Range

Manki range is located in the South-west region of Honavar forest division. It lies between

74°27’16.502” to 74°38’43.221 east longitude and 13°04’46.562 to 14°14’40.396 north latitude

and extends over an area of 23870 hectares which is 14.04% of the total area of the division.

Range headquarters is in Manki village of Honavar taluka and covers 25 revenue villages of the

taluk. and 3 villages of Bhatkal taluka comes under its jurisdiction. Range is administratively

divided in to 5 forest section and 12 beats. Land use in this range has 80.36 percent of forest land

which is evergreen to semi-evergreen. Range is bordered by Gersoppa Range & Shimoga district

at eastern side, Honavar Range at north, Bhatkal Range at south and Arabian Sea to the west,

The coast line is 15.75 km long. Important beaches are Manki beach, Bailur beach and

Murdeshwar beaches. Range covers 70.55 hectare of estuarine part of Sharavathi River with

degraded mangroves due to high fluctuation/variation in salinity because of Sharavathi Tailrace

hydroelectric power generation; these degraded Mangrove are found in Anilgod beat of Anilgod

section and Magod beat of Hadi section. Creeks are Manki creek (19.63h), Mavalli creek (17.8

h) and Bailur creek. Mangroves are found in Manki and Mavalli beat. Beat wise detail mangrove

area, species and potential area are given below (Figure 3.3.5 and 3.3.6)


90

Figure 3.3.5: MAVALLI BEAT

Beat area (ha) 3738 No. of mangrove patches 17 Mangrove area (ha) 3.35 Perimeter in km 5.07 Total area for planting (ha) NA Dominant species Acanthus ilicifolius,

Sonneratia alba, Excoecaria agallocha

Recommended Species Sonneratia alba Creek Mavalli creek Taluk Bhatkal


91

Figure 3.3.6: MANKI BEAT

Beat Area (ha) 2648 No. of mangrove patches 5 Mangrove area (ha) 0.62 Perimeter in km 1.63 No. of potential patches for planting 3 Total area for planting (ha) 0.467 Dominate Species Acanthus ilicifolius,

Acrostichum aureum, Aegiceras corniculatum, Sonneratia alba

Recommended Species Sonneratia alba Creek Manki creek Taluk Honavar


92

Mangroves of Honavar Range

Figure 3.3.7. Administrative map of Honavar Forest Range

Honavar range is located in the central west of Honavar forest division. It lies between 74° 24'

34.494"” to 74° 39' 43.772" E and 14° 11' 58.482" to 14° 23' 23.520" N and extends over an area

of 31660 hectare which is 18.63 percent of the total area of the division. Range headquarters is in

Honavar town and covers 52 revenue villages of Honavar taluka. Range is administratively

divided in to 4 forest section and 11 beats.

Land use in this range is 61.81 percent of forest land which is more or less evergreen. Range is

bordered by Gersoppa range and Kyadgi range(Sirsi division) towards eastern, Kumta range to

north, Manki range to south and Arabian Sea to west. The coastline has a length of 18.06 km.

Important beaches are at Kasarkod and Haldipur beach. An island Basavarajdurg occurs close to

the mouth of river Sharavathi. Major estuary is Sharavathi –Badgani esturine complex; 2240 ha

in area out of this 3043 hectares of estuarine complex falls in Honavar Range. Creeks:

Apsarkondai creek (1.3h)

Mangroves are found in Kasarkod, Honavar and Haldipur beats of Honavar section, Aunsalli

beat of Salkod section and Hadinbal and Jalvalli beats of Hadinbal section. Beat wise detail

mangrove area, species and potential area are given in Figures 3.3.8-3.3.11.


93

Figure 3.3.8: KASARKOD BEAT

Beat Area (ha) 4507 No. of mangrove patches 117 Mangrove area (ha) 54.48 Perimeter in km 48.34 No. of potential patches for planting 60 Total area for planting (ha) 99.43 Dominate Species Sonneratia caseolaris,

Kandelia candel, Acrostichum aureum, Acanthus ilicifolius, Sonneratia alba, Rhizophora mucronata, Avicennia officinalis, Excoecaria agallocha, Acrostichum aureum,

Recommended Species

Sonneratia caseolaris, Kandelia candel, Avicennia officinalis, Sonneratia alba, Rhizophora mucronata, Excoecaria agallocha, Aegiceras corniculatum

Estuary Sharavathi Taluk Honavar


94

Figure 3.3.9: HONAVAR BEAT

Beat Area (ha) 5707 No. of mangrove patches 171 Mangrove area (ha) 49.07 Perimeter in km 47.98 No. of potential areas for planting 41 Total area for planting (ha) 30.57 Dominant species Sonneratia caseolaris,

Avicennia officinalis, Acanthus ilicifolius, Kandelia candel, Excoecaria agallocha, Rhizophora mucronata, Sonneratia alba

Recommended species

Sonneratia caseolaris, Avicennia officinalis, Sonneratia alba, Excoecaria agallocha, Kandelia candel, Aegiceras corniculatum

Estuary Sharavathi-Badgani esturine complex

Taluk Honavar


95

Figure 3.3.10: HALDIPUR BEAT

Beat Area (ha) 3232 No. of mangrove patches 119 Mangrove area (ha) 13.53 Perimeter in km 21.52 No. of potential areas for planting 28 Total area for planting (ha) 26.13 Dominant species Acanthus ilicifolius,

Avicennia officinalis, Sonneratia alba, Excoecaria agallocha

Recommended species

Avicennia officinalis, Sonneratia alba, Excoecaria agallocha

Rivers Badgani estuary Taluk Honavar, Kumta


96

Figure 3.3.11: AUNSALLI BEAT

Beat Area (ha) 2952 No. of mangrove patches 36 Mangrove area (ha) 9.96

Perimeter in km 6.88 No. of potential areas for planting 6 Total area for planting (ha) 4.454

Dominant species

Acanthus ilicifolius, Excoecaria agallocha,

Recommended species

Excoecaria agallocha, Avicennia officinalis

Estuary Badgani

Taluk Honavar, Kumta


97

Mangroves of Kumta Forest Range

Figure 3.3.12. Administrative map of Kumta Forest Range

Kumta range is located in the cenral part of Honavar forest division. It lies between 74° 21'

1.230" to 74° 41' 49.074"east longitude and 14° 20' 36.805"to 14° 32' 8.794"north latitude and

extends over an area of 30,730 hectare which is 18.08% of the total area of the division. Range

headquarters is in Kumta town and covers 59 revenue villages of Kumta taluk and 4 villages of

Honavar taluk. Range is administratively divided in to 3 forest sections and 10 beats. Range is

having 66.97 percent of forest land which is evergreen to semi-evergreen and secondary

deciduous. This range is bordered by Kyadagi range of Sirsi division to the eastern, Katgal,

Hiregutti and Janmane ranges to north, Honavar range to south and Arabian Sea to west. The

coastline is of 23.25 km long. Important beaches are at Dhareshwar, Kumta and Baad.

Range covers 1,466 hectares of estuary in part of Aghanashini river estuary out of its total

waterspread of 4,950 ha, and 255 ha of Badagini estuarine region

Creeks: Kumta creek (238 ha) and Dhareshwar creek (4 ha)

Mangroves are found in Kumta, Manaki and Chandavar beats of Chandavar section. Beat wise

detail mangrove area, species and potential area are presented in Figures 3.3.13-3.3.14.


98

Figure 3.3.13: MANAKI BEAT

Beat area (ha) 5158 No. of mangrove patches 160 Mangrove area (ha) 26.49 Perimeter in km 46.10 No. of potential areas for planting 12 Total area for planting (ha) 22.827 Dominant species Sonneratia caseolaris,

Excoecaria agallocha, Kandelia candel, Avicennia officinalis, Sonneratia alba, Acanthus ilicifolius, Rhizophora mucronata, Aegiceras corniculatum, Avicennia marina

Recommended species

Sonneratia alba, Avicennia officinalis, Kandelia candel, Rhizophora mucronata, Excoecaria agallocha, Aegiceras corniculatum,

Estuary Aghanashini Taluk Kumta


99

Figure 3.3.14: KUMTA BEAT

Beat Area (ha) 4820 No. of mangrove patches 296 Mangrove area (ha) 22.99 Perimeter in km 61.48 No. of potential patches for planting 70 Total area for planting (ha) 67.866 Dominant species Acanthus ilicifolius,

Avicennia officinalis, Rhizophora mucronata, Excoecaria agallocha, Kandelia candel, Avicennia marina, Sonneratia alba, Aegiceras corniculatum

Recommended species

Avicennia officinalis, Rhizophora mucronata, Excoecaria agallocha, Kandelia candel, Avicennia marina, Aegiceras corniculatum, Sonneratia alba

Estuaries/creeks Badgani estuary, Kumta creek, Dhareshwar creek

Taluk Kumta, Honavar


100

Mangroves of Katgal Forest Range

Figure 3.3.15. Administrative map of Kumta Forest Range

Katgal range is located in the North-east part of Honavar forest division. It lies between 74° 22'

43.540"to 74° 35' 24.535"east longitude and 14° 25' 34.322" to 14° 36' 44.207" north latitude

and extends over an area of 24360 hectare which is 14.33 percent of the total area of the division.

Range had its headquarters in Katgal hamlet of Antarvalli village of Kumta Taluk and covers 36

revenue villages of Kumta taluk and 2 villages of Ankola taluk came under its jurisdiction.

Range is administratively divided in to 3 forest section and 12 beats. The land use in this range is

81.83 percent of forest land which is moreover evergreen. Range is bordered by Janmane range

of Sirsi division at Eastern side, Heregutti range at North side Kumta range surrounds at south

and West, It covers many estuarine island of Aghanashini

About 1158hectare of water spread area of Aghanashini estuarine region fall in this range(4950

h)

Mangroves are found in Mirjan and Katgal beats of Katgal section . Beat wise detail mangrove

area, species and potential area are given in Figure 3.3.16.


101

Figure 3.3.16: MIRJAN BEAT

Beat Area (ha) 3287 No. of mangrove patches 129 Mangrove area (ha) 83.85 Perimeter in Km 69.21 No. of potential patches for planting 19 Total area for planting (ha) 35.669 Dominate Species Avicennia officinalis,

Sonneratia alba, Sonneratia caseolaris, Kandelia candel, Porteresia coarctata, Excoecaria agallocha, Rhizophora mucronata, Rhizophora apiculata, Acrostichum aureum, Acanthus ilicifolius, Aegiceras corniculatum, Avicennia marina

Recommended Species

Avicennia officinalis, Sonneratia alba, Kandelia candel, Rhizophora mucronata, Excoecaria agallocha, Rhizophora apiculata, Sonneratia caseolaris, Aegiceras corniculatum

Rivers Aghanashini estuary Taluk Kumta


102

Mangroves of Hiregutti Forest Range

Figure 3.3.17. Administrative map of Hiregutti Forest Range

Hiregutti range is located in the North part of Honavar forest division. It lies between long. 74°

17' 31.828" to 74° 34' 52.728"E and lat. 14° 30' 32.354" to 14° 41' 20.506" N and extends over

an area of 31,360 hectare which is 18.45 percent of the total area of the division. Range has its

headquarters in Hiregutti village of Kumta Taluk and covers 28 revenue villages of the taluk and

20 villages of Ankola taluk. Range is administratively divided in to 4 forest section and 11 beats.

The land use in this range is 65.87% forest land which cover evergreen to semievergreen and

secondary moist deciduous type forests.

Range is bordered by Janmane range of Sirsi division at Eastern side, Ankola and Mastikatta

ranges of Karwar forest division to north side Kargal and Kumta ranges to south and Arabian Sea

to west. The coastline is 16.19 km. long. Important beaches are Gokarna beach, Om beach,

Kudle beach and Nadumaskeri beach. Range covers 330.7 ha water spread area of Gangavali

estuary out of its 769.7ha and 2326 ha of Aghanashini estuary, out of its 4950 ha total area.

This range is by far most important for mangroves. Beat-wise detail mangrove area, species and

potential area are given in Figures 3.3.18-3.3.20.


103

Figure 3.3.18: HIREGUTTI BEAT

Beat Area (ha) 2756 No. of mangrove patches 50 Mangrove area (ha) 21.94 Perimeter in km 29.29 No. of potential patches for planting 7 Total area for planting (ha) 157.69 Dominant species Avicennia officinalis,

Rhizophora mucronata, Sonneratia alba, Excoecaria agallocha, Acanthus ilicifolius, Rhizophora apiculata, Aegiceras corniculatum, Kandelia_candel

Recommended species

Rhizophora mucronata, Excoecaria agallocha, Avicennia officinalis, Sonneratia alba, Rhizophora apiculata, Aegiceras corniculatum

Estuary Aghanashini estuary Taluk Kumta


104

Figure 3.3.19: MADANGERI BEAT

Beat Area (ha) 7233 No. of mangrove patches 190 Mangrove area (ha) 61.93 Perimeter in km 82.84 No. of potential areas for planting 38 Total area for planting (ha) 549.30 Dominant species Avicennia officinalis,

Rhizophora mucronata, Excoecaria agallocha, Sonneratia alba, Avicennia marina, Acanthus ilicifolius, Rhizophora apiculata, Kandelia candel, Aegiceras corniculatum,

Recommended Species

Rhizophora mucronata, Avicennia marina, Excoecaria agallocha, Avicennia officinalis, Sonneratia alba, Kandelia candel, Rhizophora apiculata

Estuaries Gangavali, Aghanashini Taluks Kumta, Ankola


105

Figure 3.3.20: KENKANI-SHIVAPURA BEAT

Beat Area (ha) 1926 No. of mangrove patches 5 Mangrove area (ha) 3.93 Perimeter in km 2.06 No. of potential patches for planting 5 Total area for planting (ha) 1.402 Dominant species Acanthus ilicifolius,

Acrostichum aureum, Aegiceras corniculatum, Avicennia officinalis, Excoecaria agallocha, Kandelia candel

Recommended species

Avicennia officinalis, Excoecaria agallocha, Kandelia candel

Rivers Gangavali estuary Taluk Ankola


106

ANNEXURE-I

Location and Area (h) of mangrove patches in Bhatkal Range

Sl.No. Section Beat Location Mangrove

patch Area(h)

River Longitude Latitude

1 Bhatkal Bhatkal 74.51974 14.02544 1.81857 Venkatapur estuary

2 Bhatkal Bhatkal 74.54794 13.98271 1.12840 Bhatkal creek



5 Shirali Shirali 74.50906 14.04129 0.78095 Venkatapur estuary





























34 Shirali Shirali 74.50318 14.04721 0.16170 Venkatapur estuary Continued……


107





















55 Belke Hadeen 74.54678 13.95692 0.09595 Tannirmadi creek




















108












85 Belke Belke 74.57045 13.94986 0.05721 Belke creek















100 Belke Hadeen 74.56760 13.95057 0.04673 Belke creek











111 Bhatkal Bhatkal 74.52474 14.02242 0.04052 Venkatapur estuary Continued……


109









































110






























180 Belke Belke 74.57113 13.94995 0.01724 Belke creek













111










































112

ANNEXURE-II

Location and Area (h) of mangrove patches in Manki Range

Sl.No. Section Beat Location Mangrove

patch Area(h)


1 Kudrige Mavalli 74.48916 14.11699 0.84855 Mavalli creek






7 Manki Manki 74.47278 14.18959 0.18799 Manki creek




11 Kudrige Mavalli 74.48959 14.08552 0.10862 Murudeshwar









20 Kudrige Mavalli 74.49048 14.08376 0.03662 Murudeshwar creek




113

ANNEXURE-III

Location and Area (h) of mangrove patches in Honavar Range

Sl.No Section Beat Location Mangrove

patch Area(h)


1 Salkod Aunsalli 74.43507 14.36915 7.98433 Badgani estuary

2 Honavar Kasarkod 74.45447 14.25175 6.06041 Sharavathi estuary

3 Honavar Honavar 74.46325 14.27640 5.21711 Sharavathi estuary




7 Honavar Haldipur 74.41933 14.33115 2.52062 Badgani estuary

8 Honavar Honavar 74.42657 14.32289 2.49461 Badgani estuary



























35 Honavar Kasarkod 74.43845 14.26260 0.78250 Sharavathi estuary Continued……


114










































115


























101 Hadinbal Jalvalli 74.48821 14.26968 0.30773 Sharavathi estuary














115 Honavar Honavar 74.46501 14.27483 0.23953 Sharavathi estuary Continued……


116










































117








163 Honavar Kasarkod 74.44437 14.23079 0.14099 Apsarkonda creek




167 Hadinbal Hadinbal 74.51420 14.28800 0.13453 Sharavathi estuary






























118








































235 Honavar Honavar 74.42370 14.30936 0.06771 Badgani estuary Continued……


119










































120








































315 Honavar Honavar 74.42844 14.32234 0.03491 Badgani estuary Continued……


121








































355 Honavar Haldipur 74.42484 14.32798 0.02190 Badgani estuary Continued……


122








































395 Salkod Aunsalli 74.43471 14.37638 0.01289 Badgani estuary Continued……


123










































124
















125

ANNEXURE-IV

Location and Area (h) of mangrove patches in Kumta Range


patch Area(h)


1 Chandavar Manaki 74.38941 14.47125 2.76554 Aghanashini estuary






7 Chandavar Kumta 74.40827 14.40994 0.88788 Kumta creek





12 Chandavar Kumta 74.42419 14.35760 0.71541 Badgani estuary



















31 Chandavar Kumta 74.40363 14.38587 0.36145 Dhareshwar creek






Continued……


126













49 Chandavar Chandavar 74.44607 14.38300 0.25611 Badgani estuary




























Continued……


127










86 Chandavar Kumta 74.40828 14.41885 0.14540 Aghnashini estuary































Continued……


128









































Continued……


129









































Continued……


130





201 Chandavar Kumta 74.40767 14.41913 0.04774 Aghnashini estuary




































Continued……


131









































Continued……


132


































310 Chandavar Kumta 74.40587 14.37219 0.01933 Ramangindi







Continued……


133









































Continued……


134









































Continued……


135
















412 Chandavar Kumta 74.40637 14.37222 0.00712 Ramangindi
























Continued……


136



































137

ANNEXURE-V

Location and Area (h) of mangrove patches in Katgal Range


patch Area(h)


1 Mirjan Mirjan 74.39062 14.49797 19.30224 Aghanashini estuary




































Continued……


138









































Continued……


139








84 Katgal Katgal 74.46596 14.45627 0.09284 Aghanashini estuary

































Continued……


140



















141

ANNEXURE-VI

Location and Area (h) of mangrove patches in Hiregutti Range


patch Area(h)


1 Madangeri Madangeri 74.30132 14.59179 6.7076 Gangavali estuary

2 Madangeri Madangeri 74.37355 14.56935 5.8237 Aghanashini estuary

3 Hiregutti Hiregutti 74.38478 14.54834 5.3271 Aghanashini estuary


5 Gundbal Kenkane-Shivapur 74.39314 14.59616 3.6972 Gangavali estuary
































Continued……


142



















55 Gundbal Moralli 74.41588 14.61248 0.3532 Gangavali estuary






















Continued……


143









































Continued……


144








































Continued……


145








































Continued……


146









































Continued……


147














148

ANNEXURE-VII

Availability of potential Area (h) for Mangrove planting in Bhatkal Range

Sl.No. Section Beat Location Area for

planting (ha)


1 Shirali Shirali 74.51106 14.02885 4.3680 Venkatapura estuary


3 Bhatkal Bhatkal 74.52060 14.02350 2.5440 Venkatapura estuary


























29 Bhatkal Bhatkal 74.51931 14.02962 0.1060 Venkatapura estuary Continued……


149












ANNEXURE-VIII

Availability of potential Area (h) for Mangrove planting in Manki Range


planting (ha)






150

ANNEXURE-IX

Availability of potential Area (h) for Mangrove planting in Honavar Range


planting (ha)




































35 Honavar Haldipur 74.41807 14.34335 1.0590 Badgani estuary Continued……


151

























60 Hadinbal Jalavalli 74.51233 14.24698 0.5250 Sharavathi estuary
















152









































153

























154

ANNEXURE-X

Availability of potential Area (h) for Mangrove planting in Kumta Range


planting (ha)




































35 Chandavar Kumta 74.40772 14.41734 0.5300 Kumta creek Continued……


155






































Continued……


156











ANNEXURE-XI

Availability of potential Area (h) for Mangrove planting in Katgal Range


planting (ha)






















157

ANNEXURE-XII

Availability of potential Area (h) for Mangrove planting in Hiregutti Range


planting (ha)


1 Madanderi Madanderi 74.36523 14.56166 220.6280 Aghnashini estuary




5 Madanderi Madanderi 74.30130 14.59443 43.4350 Gangavali estuary













18 Gundbal K-Shivpura 74.39078 14.59504 0.5950 Gangavali estuary




















158

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Conservation and Management of Mangroves in Uttara Kannada