FLORISTIC ANALYSIS

C.N.Sunil “Studies on flowering plants diversity of Alappuzha district, Kerala ” Thesis. Department of Botany , University of Calicut, 2000

FLORISTIC ANALYSIS

It is an established view that Indian land mass had past connection with Sri Lanka,

South America, Africa, Malesian Islands, Madagascar, Australia and Antartica of the

Gondwanaland and had floristic similarities between these regions. Nayar (1982) had

brought out several examples to substantiate this view and the origin of Indian flora. He

was of the view that characteristic flora of India is that of Peninsular India which actually

is relicts of a bygone age as demonstrated by the presence of more paleo-endemics and the

affinity of the flora of the Western Ghats in Peninsular India with that of Malesian region

and Sri Lanka. The present study also substantiate these views by the findings of many

species from the area of the present study with their distribution extended to the above

said regions.

From a comparatively small area of 1414 sq.km. studied (compared to other

districts in Kerala), a total of about 3 100 field numbers were collected. On analysis, they

were found to be belonging to 1082 species coming under 612 genera, spread over 137

families (Fig. 2). The total number of species collected from Alappuzha district forms

about 28% of the flora of the Kerala State and more than 6% of the flora of India. A

better estimation shows that the entire Kerala region with 38,863 sq.km. may harbour

about 3800 species of flowering plants. Analysis of flora of Tamil Nadu showed that the

state with 1,30,069 sq.krn. harbours c. 5640 species, whereas the whole country is

estimated to have a total of 17,000 species distributed in an area of 32,87,263 sq.km.

Alappuzha district contains roughtly 765 species11 000 sq. km. The Kerala region contains

about 97 species/ 1000 sq. km., whereas Tamil Nadu contains only 43 species11 000 sq.km.

The country's total species concentration is only 5.111000 sq.km. From this analysis the

floristic richness of the district relative to the state, neighbouring state and the whole

country is very clear. A comparative floristic analysis of other districts of Kerala is given

in the Table 2. From this it is clear that even though it is the smallest district with little

altitudinal variation, no forests with high population densities, it is floristically rich in

diversity and number of species.

Table 2. Comparison of the Flora of Alappuzha with Other District Floras of Kerala

Name of the Flora

Flora of Cannanore District

Flora of Calicut District

Flora of Palghat District

Flora of Malappuram District

Flora of Kottayam District

Flora of Pathanamthitta District

Flora of Thiruvananthapuram District

Flowering Plant Diversity of Alappuzha District

Number of species

1132

983

1355

8 13

1151

1250

1270

1082

Area (sq.km-)

3,670

600

4,400

3,548

2,204

2,697

2,191

1414

Species concentration (per 1000 sq.km.)

308 species11 000 sq.km.

1638 species11000 sq.km.

308 species11 000 sq.km.

229 species11 000 sq. km.

522 species11000 sq.km.

463 species11 000 sq. km.

579 species11000 sq.km.

765 species11 000 sq.km.

References

Nair & Ramachandran, 1988

Manilal & Sivarajan, 1982

Vajravelu, 1990

Babu, 1990

Antony, 1989

Anilkumar, 1993

Mohanan & Henry, 1995

Present study

The number of families, genera and species with respect to dicots and monocots

are given in the Table 3 and represented in figures 3 and 4.

Table 3. Number of families, genera and species of the study area

Dicotyledons dominate with 788 species belongng to 475 genera and 109 families.

Monocotyledons have 294 species, 137 genera and 28 families. Among dicotyledons 65

families belong to Polypetalae, 28 to Gamopetalae and 17 to Monochlamydeae. Cyperus

L. (23 spp.) and Fimbristylis Vahl (18 spp.) are the two largest genera in terms of

numerical strength of species. A total of 58 out of 137 families are represented by one

genus each and 43 with one species each. Of the total species, 61.83% is composed of

herbs (669 species) and 38.2% woody plants (413 species). Among the woody plants,

there are 199 species of trees (18.39%) and 214 species of shrubs (19.77%), including

shrubby climbers and lianas (Fig. 5). Following table (Table 4) and Fig. 6 give details of

number of plants of special groups represented in the area of present study.

Species

788

35 1

318

119

294

1082

Genera

475

2 17

197

6 1

137

612

I. Dicotyledons

a. Polypetalae

b. Ga~nopetalae

c. Monochlamydeae

11. Monocotyledons

Total

Families

109

64

2 8

17

28

137

xliii

Table 4. Number of species of special groups of plants

The top 12 families representing more than 20 species are given in the table below.

Groups

Epiphytes

Parasites

Insectivorous plants

Saprophytes

A comparison of 10 largest families of the present study area in the order of

species content, with that of the Flora of rlze Presidency of Madras (Gamble & Fischer,

19 15-1936) and Flora of British Indiu (J.D. Hooker, 1872-1 897) is given below.

No. of species

7

10

9

l

Family

Poaceae

Fabaceae

C yperaceae

Euphorbiaceae

Asteraceae

Rubiaceae

Acanthaceae

Scrophulariaceae

Convolvulaceae

Apocynaceae

Malvaceae

Verbenaceae

Families with number of species in each

Orchidaceae - 7

Convolvulaceae - 2 Loranthaceae - 2 Lauraceae - l Orobanchaceae - l Scrophulariaceae - 3 Santalaceae - l

Droseraceae - 2 Lentibulariaceae - 7

Orchidaceae - l

No. of genera

5 8

5 1

16

2 5

3 3

22

17

16

9

20

11

11

No. of species

118

107

86

56

4 1

40

3 3

29

28

23

23

2 1

Altitude is a major factor controlling species diversity; as elevation increases, the

montane and temperate elements increase. In the study area, these elements are rather

rare due to the low elevation with the highest point being 50 m above MSL.

Analysis of the first three major families

Flora of British India

1. Orchidaceae

2. Fabaceae

3. Poaceae

4. Rubiaceae

5. Euphorbiaceae

6. Acanthaceae

7. Asteraceae

8. Cyperaceae

9. Lamiaceae

10. Urticaceae -

Alappuzha District (present study)

1. Poaceae

2. Fabaceae

3. Cyperaceae

4. Euphorbiaceae

5. Asteraceae

6. Rubiaceae

7. Acanthaceae

8. Scrophulariaceae

9. Convolvulaceae

10. Apocynaceae

1. Poaceae

Flora of the Presidency of Madras

1 . Fabaceae

2. Poaceae

3. Rubiaceae

4. Acanthaceae

5. Euphorbiaceae

6. Orchidaceae

7. Asteraceae

8. Cyperaceae

9. Lamiaceae

10. Asclepiadaceae

In the order of dominance, the family Poaceae ranks first with 118 species

belonging to 58 genera. Most of the grasslands in Alappuzha district are wet grasslands.

Mostly they are with annual or perennial herbs, rarely shrubs and Bambusa bambos (L.)

Voss is the only one tree-representative of this group. The subfamily Panicoideue is

represented by 38 genera and 84 species; Pooideae by 19 genera and 33 species, and

Bambusoideae by one genus and one species. Among the 58 genera, Eragrostis and

Isclzaemum have the highest representation with 12 and 9 species respectively. The genera

Punicum and Brachiaria have 7 species and 6 species respectively. The genera Digituria

and Dimeria have 5 species each and Eclzinoc/~loa has 4 species. Genera with 3 species

each are Cyrtococcum, Pennisetum, Sacciolepis, Saccharurn Sporobolus, Paspulum and

Pu.spulidium; with 2 species each are Eleusine, Oplisn~enus, Oryzu, Pogonutlzerun~ and

Seturiu. Thirty nine genera are represented by one species each.

The 8 endemic species viz., Arundinella leptocklou, Dimeriu copeunu, D. copei,

D. luwsonii, D. kulavoorensis, Isclzaemum truvancorense, I. vembanudense and I.

thomsoniunum of Peninsular India are present in the district. Of these, Dimeriu

copeunu.I>. copei and D. ku1avooren.si.s were found to be locally endemic to the

Alappuzha district. The family showed about 6.8% of endemism. All the endemic species

are with very restricted distribution and most of them are rare.

About 13.5% of the total species of this family are rare. The collection of

Cenchrus echinatus from the district forms a new record for Peninsular India and another

rare grass - Sacciolepis curvata - forms a new record for Kerala. Dimeria copeuna, a new

species reported by Sreekumar et al. (1981) from Thrikkunnapuzha could not be located

during the present study. The most common grass species include Alloteropsis cimicinu,

Chrysopogon aciculatus, Braclziaria milirformis, B. rumosa,Cynodon dactylon, Digitaria

ciliaris, D. longljloru, Panicum repens, Eragrostis unioloides, DuctyZoctenium uegyptium,

Eleusine indica, etc. The relative abundance of grasses of Alappuzha district

with that of Kerala state and Sri Lanka is given in the following table.

I Area I No. of genera I No. of species I

Kerala state

Sri Lanka

Alappuzha District

* excluding Bambusoideae

2. Fabaceae

58

This family is the second dominant one represented by 51 genera and 107 species

under 3 subfamilies. Of this, the subfamily Faboideae alone contains 71 species under 34

genera.

118

This family is with a high degree of diversity in habit and habitat. It includes trees,

herbs and climbers. The common tree species are: Ihlbergiu lutrJi,lia, Erytlzrinu

varieguta, Pongumiu pinnatu, Gliricidiu sepium, ( :ussiu fistulu, C. siumeu, Delonh regiu,

TurnurinLius indicu, Acucia uuriculrformis and Sumuneu sumun. There are 24 climbing or

twining species of which the notable are: C:entrosemu pubescens, Derris trfoliutu, D.

scandens, D. tIzyrs.~jloru, Clitoriu ternuteu, hfucunu pruriens, Caesulpiniu mimosoides, C

nugu and C: bonduc. The largest genus is (~u.ssiu, having 9 species, followed by

Desmodium and Crotuluria with 8 species each. In this family there are about 19 species

which are very rare with restricted populations. Out of the total 107 species, 2 are

endemic to Peninsular India. These species are Zorniu quilonensis and Dulbergiu Izorridu.

The subfamily Caesalpinioideae is represented by 21 species. The subfamily

Mimosoideae is represented by 15 species of which almost all species are pantropical in

distribution. A general analysis of the family Fabaceae with its constituent taxa

represented in Alappuzha district is given in the following table.

No. of genera

No. of species

No. of species of Faboideae

No. of species of Caesalpinoideae

No. of species of Mimosoideae

Genera with 5 or more species

Species endemic to Peninsular India

Number of Tree members

Shrubs and Climbers

Herbs

Rare species

5 1

107

7 1

2 1

15

4

2

26

36

45

25

3. Cyperaceae

The third rich and diverse family is Cyperaceae represented by 16 genera and 86

species. Among the 16 genera, Cyperus and Fimbristylis have the highest representation

with 23 and 18 species respectively. The genera Eleoclzaris and Mariscus have 6 species

each. Genera with 5 species each are Scleria, Scl~oenoplectus, Pycreus and Kyllinga; with

3 species each are Fuirena and Hu1bostyli.v; with 2 species is Rlzynchospora. The genera

with single species are Remirea, Rikliellu, Lipocarplza, Hypolytrum and dip lac run^.

The representative species exhibit all forms as herbaceous annuals or perennials,

and are confined to restricted habitats, mostly on the wet or marshy lowlands. Among

these, Diplacrum caricinum, Fimbristylis cinnamometorum, F. insignis, Kyllinga

polyphylla, Rhynchospora wiglltiana, Scleria sumatrensis, Cyperus bifar, Pycreus

macrostachyos and Remirea maritima are extremely rare. Fimbristylis narayunii is the

only one endemic species representative of this family. The collection of Eleoclzaris

lankana and Kyllinga polyplzylla form new records for India.

Endemism

The word 'endemic' is ascribed to any taxonomic unit or taxon which occurs in a

restricted area, usually isolated by geographical or temporal barriers. Turrill's (1964)

contention that next to islands, the peninsular regions provide favourable conditions for

endemism is acceptable so far Peninsular India is concerned. Ahemedullah and Nayar

(1986) listed 1932 taxa out of the estimated 6500 species as endemic to Peninsular region,

which form about 29.7%. There is no endemic family but 58 genera are endemic of which

47 are monotypic.

Present analysis of the flora of Alappuzha shows that 59 species (Appendix-11) are

endemic to Peninsular India which form 5.45% (Fig. 7) of the total 1082 species. Of

these, 4 species were found to be locally endemic to the Alappuzha district. Poaceae has

maximum endemics with 8 species. Rubiaceae has 5, and Dipterocarpaceae and

Lythraceae have 3 species each.

xlviii

RarityNulnerability of species

Critical analysis of the flora was done with respect to the species

raritylvulnerability, on the basis of their range of distribution, strength of population and

threats faced. The analysis showed that 133 species (Appendix-111) are extremely rare,

with very few scattered populations or even few individuals. The percentage of total rarity

of the flora is 12.1 which is fairly a high (Fig. 8). These state of affairs demand immediate

conservation measures to be undertaken to save those species. It is interesting to note that,

during the present study, 3 species viz., Aponogeton appendiculatus, Syzygium

travancoricum and Strophanthus wightianus listed in the Red Data Book of Indian Plants

(Sastry & Nayar, 1987-1990) under the category 'rare and endangered' were located.

Alien species

During the study, it is noted that a large number of exotic plants have spread to this

area. Introduced exotic species often become aggressive colonisers and they threaten the

habitat of the native species. In such cases native species are on the run for survival.

There are 83 species listed in this category (Appendix-IV). Most of these plants are native

of Tropical America. The family Asteraceae is the largest in this regard, with 16 alien

species. Among these, Mikania cordata has become a serious threat to native species

especially to those plants in sacred groves. Chromolaena odorata and Ageratum

conyzoides are other 2 members of this family which are well established. Another

troublesome weed is Eichhornia crasspes. This species is well established in wetlands.

Centrosema pubescens, another well established alien species has occupied almost all

areas. The other well established weedy species are Croton hirtus, Euphorbia

heterophylla, Sesamum radiatum, Hiptis suaveolens, Alternanthera philoxeroides, A.

tenella, Synedrella nodrflora, Spermacoce latrfolia, Scoparia dulcis, Tridax procumbens

and Mitracarpus hirtus.

Wild relatives of Crop-Plants

It is also accepted that man needs a reservoir of wild species in order to prevent

genetic erosion of his cultivated crops. A species once lost cannot be recreated and this

results in the loss of millions of years of evolution.

Fig.7 Relative uhundan

Rare 131 112.191 -

-- lr endenlic species

Rg.8 Relative abundance of rare species

About 88 species which are closely related to cultivated crop-plants have been

collected from the district (Appendix-V). Among these 7 are wild relatives of cereals and

millets, 4 species are of leguminous crops. There are 16 species of fruit-crop relatives. In

fruit crops, Madhuca nerifolia is very rare. Many species belonging to Cucurbitaceae,

Amaranthaceae, Solanaceae and Dioscoreaceae are wild relatives of existing cultivars.

Momordica dioica is a close relative of bittergourd. There are four species of

Trichosantltes which are closely related to the cultivated snake gourd. Lufla aegyptiacu

is another wild relative of smooth gourd. A close relative of nutmeg (Myristica fragrans),

Myristica malabarica, is with large fruits and brightly coloured aril, and is very rare and

endemic. Spice relatives are represented by 8 species belonging to Alpinia, Cinnamomum,

Curcuma, Prper and Zingiber. Relatives of vegetative crops such as Abelmoschus,

Amaranthus, Solanum, etc. and that of tuber crops such as Dioscorea are also represented.

Medicinal Plants

A large number of medicinal plants also occur in the district (Appendix-VI). The

medicinal application of these species ranges from their use in simple disease like

headache to even cases of cancer. Many of the medicinal plants are becoming more and

more rare because of their over exploitation by drug industries. For example, the wild

populations of the plants like RauvolJia serpentina, Sida alnifolia, Desmodium

gangeticum, Trichosanthes cucumerina, Phyllanthus amarus, Aerva lanata, Gloriosa

superba, Aristolochia indica, Indigofera tinctoria, etc. have become critically reduced.

New distributional records and reports

The following plants collected from the district form new records for India, South

India and Kerala.

I. For India

The finding of the species Kyllinga polyphylla Willd. ex Kunth and Eleocl~aris

lankana Koyama (Cyperaceae) during the present study from the district formed new

reports of the taxa from the country.

11. For South India

The finding of the species Voacangu grandrfolia (Miq.) Rolfe (Apocynaceae) and

Cenclzrus echinutus L. (Poaceae) during the present study from the district formed new

reports of the taxa from South India.

III. For Kerala

The following species indicated below have been recorded for the first time from

Kerala during the present study: Succiolepis curvuta (L.) Chase (Poaceae), Glossostigmu

diandra (L.) Kuntze (Scorphulariaceae), Spilanthes uliginosa SW. (Asteraceae), Cussia

sericea SW. (Fabaceae), Rom. and Croton hirtus L'Herit. (Ephorbiaceae).

Extended distribution of Species

Some newly reported species like Diodia teres Walt (Rubiaceae), Desmodium

scorpiurus (Swartz) Desvaux and Staurogyne glutinosa (Wall. ex Clarke) 0. Kuntze

(Acanthaceae) from other districts of the state were collected from Alappuzha district

during the present study.

New species discovered by other workers

1 . Aponogeton appendiculatus V . Bruggen (Blumea 16:265.1968)(Aponogetonaceae),

collected from Alappuzha brackish waters.

2. Dimeria copeana Sreekumar, et al., (J. Bombay Nat. Hist. Soc. 78(3): 577. 1981)

(Poaceae), collected from Thkkunnapuzha.

3. Dimeria copei Ravi (Blumea 41: 25 1. 1996) (Poaceae), collected from AIR

Campus, Kalavoor.

4. Dimeria kaEavoorensis Ravi (Blumea 41: 253. 1996) (Poaceae), collected from

AIR Campus, Kalavoor.

THREATS TO THE FLORA

As anywhere else, the most serious threat to the flora is from man. Being the

smallest district with thickly populated area, the threat to the flora is highest here

compared to other districts of Kerala. The increase in demand of land for housing,

industrialization, construction of roads, railway-line, etc. has affected the natural

vegetation in the area.

Many sacred groves of the district are now threatened and altered both in terms of

size,vegetation structure and species composition. Some of the groves are completely

devoid of vegetation and only the temples exist although still known as 'kavus'. There

were many instances where even the worship places were removed by a process called

'Avahichu kudiyiruthal' (absorb the spirit and rehabilitate) where in the temple deity is

transferred to a new place after conducting special 'poojas' (Unnikrishnan, 1995). Thus the

grove was freed from the power of the God and the vegetation cleared for conversion to

alternate landuse. Sacred groves are relatively small and are therefore island-like. Studies

of island biogeography have shown that such fragments may suffer extinctions of species.

Ownership of the groves and the beliefs of the people on the GodJGods "living" inside the

groves are two decisive factors which decide the conservation of the sacred groves. More

than 99% of the sacred groves are privately owned (Family owned, where management

will be looked after by a single family as in Mannarassala and Sharangakavu).

Vandanamkavu is the only one controlled by Devaswom Board. The break-up of the old

joint families into nuclear families has resulted in a lack of man power to protect family

sacred groves. There is a gradual erosion in the beliefs of the people in the power of the

deities reigning the groves. Such erosion has lead to the gradual decline in the extent of

the groves and their gradual disappearance. Exotic weeds like Mikania cordata,

C/zromolaena odorata, etc. also cause destruction of vegetation of kavus. Encroachment,

grazing, collection of firewood, preparation of green manure, construction of roads, felling

of trees, etc. are the other factors those lead to the destruction of kavus.

Mangroves of Alappuzha district have been severely degraded due to many

reasons. The constant and indiscriminate cutting of mangroves for fire wood, reclamation

liv

of mangroves for cultivation and various construction activities, conversion of the

mangrove into coconut husk retting, etc. are some of the reasons for degradation of

mangroves. Large-scale hatcheries and fish farm activities also pose a threat to the coastal

zone in general, and to mangroves in particular. Although these activities do yield

economic gains for the coastal people, the mangrove ecosystem itself is under threat in

certain areas due to aquaculture. Actually studies reveal that mangroves provide suitable

ecosystem for the development of prawn farms and fish farms.

Indeed, the recent history of Alappuzha wetlands-especially fresh-water wetlands-

are dominated by the invasions of aquatic weeds, notably Salvinia (Salvinia molesta

Mitchell) and water hyacinth (Eickhornia crassipes Mart.). Salvinia is popularly known

as 'curse of Alappuzha'. Alappuzha district has also witnessed a veritable tug-of-war

between these two weeds. When the environmental conditions favour one weed, it

subduces the other; when the conditions shift, the pattern is reversed. Why did weeds

come in and got entrenched in the water bodies which have been free from such weed

dominance for the past hundreds of years?. The single most important factor has been the

increasing pollution of the wetlands by organic waste. Increased use of the ponds, lakes,

tanks and canals for bathing and laundry, human-generated waste getting increasingly

washed in with rain water run-off, increasing use of fertilizers in agriculture, also end up

in the wetlands. All have contributed to the greater availability of 'food' for the aquatic

weeds. Aquatic weeds are seen enormously in Kuttanadu area. Thanneermukkam

regulator will be closed for the period from December to June every year. Water will be

stagnated in this zone during this time and entry of salt water will be prohibited. Besides

these usage of excessive pesticides and fertilizers, disposal of human generated wastes,

retting of coconut husk and leaves, etc. cause to the serious pollution of water here and

consequently weed growth will increase. The following table gives the comparison

between the recommended and actual usage of fertilizers for paddy in the area.

1 Fertilizers I Recommended quantity I Actual usage (kgha)

In each year about 500 to 1000 tons of pesticides (organic chlorides and

organophosphates) were used exclusively in Kuttanadu area. The rest of the country can

draw a lesson from Kerala's Thaneermukkam bund system which showed that man should

not interfere with the natural system (Untawale & Jagtap, 1998). The bund was

constructed to increase the yield of paddy. However, it created a problem as a

consequence of eutrophication which resulted in the growth of the Salvinia, water

hyacinth and other aquatic weeds. Salvinia and water hyacinth are the world's fastest

growing plants, as also among the hardiest. In favourable situations these plants are

capable of thriving and out-competing other plants by the sheer force of their frenzied

growth-rate. These weeds came to India much after other aquatic weeds (such as

Nelumbo, Pistia and Lemna) did. Being recently arrived exotics, these weeds encountered

no resistance from their natural enemies, whereas the same weeds are held in check in

their native habitats of Latin America by grazers and competitors adopted to these weeds.

Therefore three factors - pollution (which provides 'food' for the weeds and reduces

competition by weakening less tolerant vegetation), fast growth-rate of the weeds

(accompanied with hardiness and competitiveness), and absence of natural forces which

could control the weeds - have all contributed to the dominance of these weeds, and the

devastation caused by these two to the wetland flora of Alappuzha district. The threat to

wetlands posed by aquatic weeds, especially Salvinia and water hyacinth, takes several

forms. They add to the loss of water from streams, ponds, lakes, canals and other water-

bodies through evapo-transpiration. The water-loss from a reservoir infested with Salvinia

is 30%-40% greater than from weed-free one (Abbasi et al., 1988). The evapo-

transpiration losses of water perpetuated by water hyacinth are even higher. They out-

compete the other plants for nutritive elements and space (Abbasi, 1997) and cause

eutrophication. The thick mats of the weeds prevent sunlight from reaching the submerged

flora and fauna, thereby cutting off their energy source and disturbing the ecosystem

(Gupta, 1979). They decay slowly, through aging and dying, in the water body. The

decaying process adds to the depletion of dissolved oxygen and spoils the water quality by

increasing the BOD, COD, pathogenic organisms, etc. The conditions become

unfavourable for the survival of useful aquatic organisms (Abbasi, 1997). In agricultural

fields, they use the fertilizers applied to the crops, multiply much faster than the crops and

render large areas out of production.

Over grazing has severely affected the vegetation of Alappuzha district especially

those belong to herbaceous and shruby plants. As per the census data of 1991 cattle

population in the district was 1192 (Bhaimy Sadasivan, 1997). Plants like Habenaria

viridrflora, Xyris complanata, Diplacrum caricinum, Fimbristylis cinnumometorum, F.

eragrostis, F. insignis, Scleria blflora, Dimeria cope;, D. kalavoorensis, Rhamphicarpa

long~fora, etc. can be seen in All India Radio Station campus in Kalavoor where the

grazing has been prohibited, whereas these plants can't be found outside' the campus due to

various reason including grazing.

Most of the hills in the midland regions have been cleared for rubber plantation.

The waste land area now supports only very few tree species and there is a definite

preponderance of herbaceous taxa. In these disturbed conditions, the recent immigrants

from other parts of tropics have found a good opportunity to outsmart the indigenous

species and dominating and ultimately eradicating the former from the area. Common

examples of such successfUlly established plants are Mikania cordata, Chromolaena

odorata, Croton hirtus, C. bonplandianus, etc. The coir retting practiced throughout

coastal area for the extraction of coir from coconut husk, is another major threat to the

vegetation of the backwaters of Alappuzha district. - 8 .