Wetland Flora

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Thiruvananthapuram

FLORISTIC ANALYSIS OF WETLANDS OF KERALA T. Sabu* and Babu Ambat** *Director (Research), ** Executive Director Centre for Environment and Development, Vattiyoorkavu P.O., Thiruvananthapuram - 13

INTRODUCTION Wetlands are “lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface, or the land is covered by shallow water” (Cowardin et al, 1979). This includes three attributes that help to delineate a wetland: (i) the area must be permanently or periodically inundated or water must be present for at least seven successive days during the growing season, (ii) the area must support hydrophytic vegetation and (iii) the substrate is predominantly hydric soils that are saturated or flooded for a sufficiently long period to become anaerobic in their upper layers. From the utilitarian point, wetlands can be defined as transitional areas between permanently flooded deepwater environments and well drained uplands that contribute a wide array of biological, social and economic benefits (Watzin and Gozzelink, 1992). Wetlands support a wide array of flora and fauna and deliver many ecological, climatic and societal functions. Scientists often refer to wetlands as the “kidneys” of the earth and forests as the “lungs” of the earth. India, by virtue of its extensive geographical stretch and varied terrain and climate, supports a rich diversity of inland and coastal wetlands. Kerala is also well known for its wetlands. These wetlands provided livelihood to the residents in the area in the forms of agricultural produce, fish, fuel, fiber, fodder, and a host of other day-to-day necessities. As long as human intervention remained minimal, the ecosystem, through its all-encompassing balancing nature, was self-cleansing. But the development demands that determine the choice of the paths, upset the natural harmony. Infrastructure development in the form of roads, railways, and other lines of communication fragmented the contiguity of the wetlands, and destroyed extensive tracts of coastal vegetation thereby upsetting the entire complex ecology; rapid urbanisation encroached into the rich and luxuriant mangrove forests, while industrial development not only caused pollution but prevented any regeneration possibilities as well; modern shrimp farms brought in the final onslaught - the irreversible destruction of wetlands. Coastal Kerala with its high density of population, cannot bear such onslaughts any longer. The degradation of the wetlands of Kerala is not an isolated event. Worldwide, wetlands are in peril. They are either being polluted, drained or filled up to give way for development. The rate of wetland loss has accelerated in recent years. Thus, the wetlands are now the most threatened ecosystems of our planet. Centre for Environment and Development

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SIGNIFICANCE OF WETLAND FLORA Aquatic plants, wherever they grow, play an important role in the ecosystem. When nature is intact, they regulate the quality of the water and provide food and shelter for its inhabitants. If nature is upset, they can disappear altogether or grow and spread at an alarming rate and can cause anything from a ‘local nuisance’ to a catastrophe that may directly threaten human life. The management of our environment has become the most important single concern of mankind today. Many aquatic plants have invaded new areas, some were deliberately planted because of their economic or decorative value or were accidentally introduced with other plants, some have settled peacefully, but others have become aggressive weeds (Cook, 1990). One key to understanding the unique characteristics of wetland plants is to understand the contribution they make to wetland ecosystems. The production of organic matter from inorganic substances or primary products is the fundamental basis of the dynamics of the ecosystems. Wetland plants have major effects in terms of the physical (temperature, light penetration, soil characteristics) and chemical environment of wetlands (dissolved oxygen, nutrient availability), and provide the basis of support for nearly all wetland biota. They are drivers of ecosystem productivity and biogeochemical cycles, in part because they occupy a critical interface between the sediments and the overlying water column (Carpenter and Lodge 1986). Although some of the adaptations possessed by wetland plant species are also found in related terrestrial species, many attributes are unique or, if shared, have reached a high degree of specialization. Mangrove forests are valued for production of fish and shell-fish, live-stock fodder, fuel and building materials, local medicine, honey and bees-wax, and for extracting chemicals used in tanning leather. Apart from that, they provide durable timber, fuel wood, and protein rich fodder for cattle, edible fruits, vegetables and traditional medicines. According to Wiegleb (1988) the wetland flora are vitally important for many reasons: Wetland plants are at the base of the food chain and, as such, are a major conduit for energy flow in the system. Through the photosynthetic process, wetland plants link the inorganic environment with the biotic one. The primary productivity of wetland plant communities varies, but some herbaceous wetlands have extremely high levels of productivity, rivaling those of tropical rain forests. And unlike many terrestrial ecosystems, much of the organic matter produced is not used directly by herbivores but instead is transferred to the detrital food chain. They provide critical habitat structure for other taxonomic groups, such as epiphytic bacteria, periphyton, macroinvertebrates, and fish (Carpenter and Lodge 1986; Wiegleb 1988; Cronk and Mitsch 1994). The composition of the plant community has implications for diversity in these other taxonomic groups. 92

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They strongly influence water chemistry, acting as both nutrient sinks through uptake, and as nutrient pumps, moving compounds from the sediment to the water column. Their ability to improve water quality through the uptake of nutrients, metals, and other contaminants is well documented (Gersberg et al. 1986; Reddy et al. 1989; Peverly et al. 1995; Rai et al. 1995; Tanner et al. 1995a, b). Submerged plants also release oxygen to the water that is then available for respiration by other organisms. They influence the hydrology and sediment regime of wetlands through, for example, sediment and shoreline stabilization, or by modifying currents and helping to desynchronize flood peaks. Vegetation can control water conditions in many ways including peat accumulation, water shading (which affects water temperatures), and transpiration (Gosselink and Turner 1978). Wetland plants are also among the tools used by wetland managers and researchers in the conservation and management of wetland areas, for example: They are routinely used to help identify or delineate jurisdictional boundaries of wetlands in the U.S. and elsewhere (U.S. Army Corps of Engineers 1987). Increasingly, the composition of the plant community and the predictable changes in community structure that result from anthropogenic disturbance are being investigated for their ability to act as biological indicators of the “health” or ecological integrity of the wetland (Adamus 1996; Mack et al. 2000). This kind of information has many potential applications including monitoring wetland condition over time or setting goals for wetland restoration or mitigation projects. Wetland plants are often used to help organize environmental inventories and research programs, and to set goals for management programs or restoration projects (Cowardin et al. 1979; Britton and Crivelli 1993; Brinson 1993). DELINEATION OF WETLAND PLANTS Most of the terminology used to describe wetland macrophytes is based on the hydrological regime that a species requires. In general, there exists a continuum of tolerance among all vascular plant species ranging from those adapted to extremely dry conditions (xeric terrestrial species) to those species that complete their entire life cycle (from seed to seed) underwater. The latter never come into direct contact with the atmosphere. Along this continuum, there are no discrete categories in terms of moisture requirements, and although it is not possible to make a division where terrestrial plants end and wetland species begin, many operational definitions exist. Wetland plants are commonly defined as plants “growing in water or on a substrate that is at least periodically deficient in oxygen as a result of excessive water content” (Cowardin et al. 1979). This term includes both herbaceous and woody species. The definition of the term hydrophyte has evolved since its inception in the late 19th century. Originally used by Europeans in the late 1800s, it was used to denote plants that grew in water, or with their perennating organs submerged in water (Sculthorpe 1967; Tiner Centre for Environment and Development

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1991). Warming (1909, as reported in Tiner, 1999) is credited as the first to arrange plant communities according to their hydrological preferences. Aquatic plants were defined as submerged species or those with floating leaves, while marsh plants were categorized as terrestrial plants. Many authors do not make a distinction between wetland plants and aquatic plants. For example, Barrett and others (1993) use the term aquatic plant in its broadest sense to include all plants that occur in permanently or seasonally wet environments. However, other authors such as Cook (1996) define (vascular) aquatic plants as those Pteridophytes (ferns and fern allies) and Spermatophytes (seed-bearing plants) whose photosynthetically active parts are permanently or semi-permanently submerged in water or float on the surface. Other authors make a similar distinction with regard to species they consider to be true aquatics, a term sometimes used to denote species that complete their life cycle with all vegetative parts submerged or supported by the water (Best 1988). Examples of families with submerged and floating-leaved species that fall in this category include the Nymphaeaceae (water lilies), Potamogetonaceae (pondweeds), Lentibulariaceae (bladderworts), and Najadaceae (naiads). Terms other than hydrophyte that have been used to describe wetland plants include: limnophyte (freshwater plant), aquatic macrophyte (plant visible to the naked eye), amphiphyte (species capable of growing on land or in water), helophyte (emergent plant), and amphibious species. FLORISTIC DIVERSITY OF KERALA WETLANDS Western Ghats of Peninsular India is one of the eighteen ‘Global Hot Spots’ of biodiversity. The diversity of climatic, edaphic and biotic regimes have shaped the evolution of over 4500 taxa of angiosperms, 117 amphibians, 150 reptiles, 508 birds, 79 mammals and an unknown number of taxa from less studied groups. By virtue of its unique location (sandwitched between the Arabian Sea on the west and the Western Ghats on the east), topography (ranging from the coastal lowlands to mountain regions intervened by vast expanse of undulating midlands) and high rainfall, Kerala provides a wide variety of aquatic habitats like rivers, streams, pools, ponds, lagoons, estuaries etc. harbouring unique types of vegetation of their own. The State has two clearly distinct rainfall seasons i.e., south west monsoon and north east monsoon resulting in near water-logged conditions in almost 20% of the total geographic area of the State. The wetlands of Kerala are treated as sites of exceptional biodiversity in the country and are characterized by several endemic species. The coastal plains have been ravaged since early times of human habitation, and most of the land is now used for housing and agriculture. Even these disturbed habitats are potential location for rapid speciation as has been amply proved from the long list of new taxa discovered and described from here during the last two decades. Geomorphologically, the wetlands in Kerala may be divided among five major systems at the broadest level as marine, estuarine, riverine, lacustrine and palustrine. Due to the unique physical characteristics Kerala endows, like backwater systems and a diverse terrain of high land, midland and low land within a thin strip of landmass of about 94

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38,864 km2, there exists much ambiguity in the classification of wetlands. Thus, major classes and types of wetlands are redefined keeping the MoEF classification system as the standard (CED, 2003). Accordingly, the wetlands of Kerala are broadly divided into i) Inland wetlands and ii) Coastal wetlands. The inland wetlands include: fresh water lakes, fresh water swamps, reservoirs and ponds. The estuaries/ backwaters, mangrove forest, Kol, Kuttanad and Pokkali wetland systems, coastal swamps, mud flats, coastal Islets (Thuruthu) and aquaculture ponds are included in the coastal wetlands category. Delineation of wetlands into the above said categories is mainly done on the basis of various parameters like location, physical extent, depth, salinity, bio-diversity etc. There are more than 32 major backwaters/estuaries in Kerala with about 28 important mangrove sites. Compared to coastal land, the highland and midland hold very few wetlands. There are seven major freshwater lakes in Kerala, which have no direct connection with the Arabian Sea, are Pookode (Wayanad); Muriad, Kattakambal and Enammakkal (Thrissur); Manakkodi (Idukki); Sasthamkotta (Kollam) and Vellayani (Thiruvananthapuram). There are also many other water resources such as ponds and tanks which is one of the specialties in Kerala. Each Panchayat/Urban local body has a number of both public and private ponds and tanks. According to Pan Fish Book (2002) there are about 6,820 Panchayat Ponds, 35,892 Private ponds, 3,357 Public Ponds, 904 Quarry ponds, 838 Irrigation tanks and 2,634 Holy ponds and streams in Kerala. The development activities in the State have also resulted in the creation of more than 40 major man-made reservoirs created by constructing dams across various rivers in the Western Ghats, and many abandoned granite quarries and clay pits which, in course of time, have provided ideal habitats for aquatic biota. The marshy and water-logged areas and vast Polders (paddy cultivating areas) associated with the backwaters and lakes and the Myristica Swamps in the Western Ghat forests are the unique wetland ecosystems of Kerala. About 53 patches of Myristica swamps have been recorded from the Kulathupuzha, Anchal forest ranges and Shendurny Wildlife Sanctuary of the Kollam and Thiruvananthapuram districts of Southern Kerala. Kerala has three wetlands of international importance viz., Vembanad-kol, Ashtamudi and Samsthamkotta lake (Ramsar sites). The Kottuli wetlands in Kozhikode District and Kadalundi in Kozhikode and Malappuram Districts were identified by the Ministry of Environment and Forests, Government of India, under National Wetland Conservation Programme. There are many scattered studies on the wetland plants of Kerala. Most of them are mainly focused at the three Ramsar sites and a comprehensive study comprising the entire wetlands is lacking. Centre for Environment and Development

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Present Study Centre for Environment and Development (CED) had completed a project on “the survey and inventory of wetlands of Kerala” in 2003. As a part of the project, floristic surveys were conducted in 11 major wetlands of Kerala (Table 1) which include six coastal and five inland wetlands. The mangrove ecosystems at Puthuvypin, Mangalavanam and Chetwai and the Kol wetland ecosystem of Thrissur (included in the Vembanad kol wetland system) were studied specifically for the floristic diversity in the specialised ecosystem. Even though the floristic studies covered all groups of plants, the field studies were mainly concentrated on Angiosperms. Phytoplanktons were studied only in some locations, but a detailed study was not attempted due to time constraints. Table 1. Details of study area No.

Name

1

Vembanad Kol wetlands

2

Veli-Akkulam Estuarine complex

3 4

5

6

7

8

9

10

11

96

Wetland type Backwaters / Estuaries and fresh water kol Backwaters / Estuaries

Ashtamudi Lake

Backwaters / Estuaries

Purathur estuary

Backwaters / Estuaries

Kadalundi Estuary

Backwaters / Estuaries

KavvaiKunhimangalam backwater system Sasthamkotta Lake

Backwaters / Estuaries

Pookode Lake

Fresh water lake

Malampuzha reservoir

Manmade wetland

Periyar reservoir

Manmade wetland

Myristica swamps of Kulathupuzha

Fresh water Swamp

Fresh water lake

Location 0

District 0

09 00’ – 10 40’ N Latitude and 76 0 00’ -77 30’ E Longitude

0

76º 51’47’’- 76º 55’ 51’’ E longitudes and 8º 29’ 6’’ – 8º 32’ 53’’ N latitudes. 08° 50' - 09° 05' N latitude and 076°35'E longitude 10°45′26″ – 10°51′19″ N latitude and 75° 53′46″ – 75°58′07 ″ E longitude 11° 04′ 15″ – 11°08′57″N latitude and 75° 48′36″ – 75° 54′ 00″ E longitude 11°59′52″ - 12° 14′ 36″ N latitude and 75° 06′ 48″ - 75°15′40″ E longitude 9 °00 ′40 ″ – 9 °04′ 05″ N latitude and 76°36′ 27″ – 76 °39 ′55″ E longitude 11° 32′ 24″ – 11° 32′ 35″ N latitude and 76° 01′ 34″ – 76° 01′ 43″ E longitude 76 °37′ 41″ – 76°44′54″E longitudes and 10°48 ′08″ – 10°53 ′41″ N latitudes. 9º 28’ 11’’- 9º 36’ 13’’ N latitude and 77º 07’ 00’’ – 77º 17’ 20’’ E longitude 8°50’ to 8°55’ North latitude and 77°5’ to 77° 15’ East longitude

Kottayam, Alappuzha, Ernakulam and Thrissur Thiruvananth apuram Kollam Malappuram

Malappuram and Kozhikode Kannur

Kollam

Wayanad

Palakkad

Idukki

Kollam

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Phytoplanktons Phytoplanktons are free floating unicellular plants and they occur as large scums on the sea surface. Though the benthic algae and other macro-vegetation also contribute significance to the primary production, in wetlands, phytoplankton plays a major role and has received much attention. The phytoplankton in the wetlands varies from freshwaters to truly estuarine and marine species. Phytoplankton in coastal wetlands has reproductive rates to offset their population, which is lost by the downstream drift. Predominance of certain species depends on favorable conditions that facilitate their rapid reproduction. Subramanyam & Sarma (1967) listed about 291 species of phytoplanktons from Kozhikode coast. Thressiamma and Nair (1981) had carried out a detailed study on the phytoplankton of Veli Lake. Shobha and Miranda (1987) in Kadinamkulam Lake and Ashtamudi estuary of Kerala. A detailed study on the phytoplaktons of selected coastal wetlands of Kerala was recently attempted by Central Inland Fisheries Research Institute (Unnnithan et al, 2005). A total of 100species of phytoplanktons were recorded. Desmidaceae had a higher representation in the northern backwaters (Neeleswaram to Azhikode) during the monsoon season, whereas this was replaced by either Bacillariophyceae or Chlorophyceae during the post-monsoon season. The southern backwaters except Ashtamudi were dominated by Bacillariophyceae during monsoon, which got replaced by Myxophyceae during the post-monsoon season. During the pre-monsoon period Chlorophyceae, Myxophyceae and Chrysophyceae showed higher percentage incidence in the southern backwaters, whereas Bacillariophyceae showed higher incidence in the northern backwaters. Campylodiscus sp., Staurastrum sp., Micrasterias sp., and Spondylosium sp. contributed to the higher density of Bacillariophyceae. Chlorophyceae represented by Microspora sp., Pediastrum sp. and Hormidium sp., contributed to the high planktonic biomass in Chettuva and Ponnani estuaries. The study also attempted the survey of phytoplankton in the canals and rivers emptying into the Vembanad lake. Blue green algae formed the biggest component contributing an average of 49% for the three canals, whereas it was 57% in the four rivers. Green algae contributed 48.5% (av.) in the canals having 11 species, but only 20% formed the population in the rivers with 13 species. In the canals, Phaeosphaera sp. had the highest mean percentage abundance (14.2%), followed by Microsproa sp., in the rivers Pediastrum sp. (4.79%) and Hormidium sp. (3.24%) showed the peak incidence. Microcystis sp (10.96%), Spirulina sp. (18.39%) representing the blue greens contributed the maximum in the canals, whereas in rivers it was Anacystis (25.56%) and Microcystis sp. (26.95%). Dinobryon was observed in the riverine zones with an average of 6.46%. Desmids (1.26% for canals; 15% for rivers) and Diatoms (0.77% for canals and 1.09% for rivers) contributed significantly to the biomass in both the water bodies investigated. Dinoflagellates were represented only by Ceratium (0.01%) in the canals. There are many scattered, unpublished surveys (mostly Ph.D thesis and M.Phil/M.Sc. dissertations) on aquatic Algae and Cyanobacteria by Madhusoodhanan and his students of Calicut University. AVN Panikker of SN College also conducted many algal surveys in Kerala. A study on marine fungi of the Kerala coast was attempted by Ravindran Centre for Environment and Development

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(2003). A compilation of all available data revealed the presence of about 90 species of Cyanobacteria, 275 species of marine/fresh water algae and 35 species of aquatic fungi in the wetlands of Kerala. Aquatic macrophytes and other wetland dependent plants Aquatic macrophytes include the aquatic angiosperms (flowering plants), pteridophytes (ferns), and bryophytes (mosses, hornworts, and liverworts). Large algae such as Nitella and Chara are also included in the category of aquatic macrophytes. The wetland plants of Kerala, particularly angiosperms, were dealt with in a number of floristic studies conducted by various institutions. Botanical Survey of India has completed the study of the District floras of Kerala. Pteridophrytes of Kerala were surveyed by Nayar and Geevarghese (1993), Santhosh and Madhusudhanan (1998), Abdul Hameed et al (2003) and Madhusoodhanan and Rajesh (in press). Detailed studies on Bryophytes of Kerala were done only for two districts – Idukki by Rajeevan (1990) and Wayanad by Manju et al (2005). However, there are comparatively few studies concentrating the aquatic macrophytes. Mangroves are the only group which caught the attention of many workers. Ramachandran et al (1986) Chand Basha (1992), Mohanan (1999) and Anupama and Sivadasan (2004) have completed detailed studies in this regard. Manilal and Sivarajan (1975) had initiated studies concentrating on the aquatic angiosperms and subsequently, Joseph (1991) under the guidance of the latter, has completed a detailed study on the aquatic angiosperms of Malabar. This work remains as the only one of that kind in Kerala, and there was no concerted attempt to prepare a comprehensive list of aquatic macrophytes of Kerala. Pookode Lake, one of the major fresh water lakes of Kerala, is the only wetland area from where the details of Bryophytes collections are known. The study by Manju et al (2005) has reported 12 Bryophyte (Table 2) from this area.

Table 2. Bryophytes recorded from Pookode Lake No. 1 2 3 4 5 6 7 8 9 10 11 12 98

Name Anthoceros crispulus (Mont.) Douin. Riccardia multifida (L.) Gray Philonotis hastate (Duby) Wijk & Marg. Bryum coronatum Schwaegr Cyathodium cavernarum Garckea flexuosa (Griff.) Marg. & Nork. Fissidens ceylonensis Dozy & Molk., Fissidens crispulus Brid. Marchantia linearis L. Ricciocarpos natans (L.) Corda Riccia fluitans L. Riccia frostii Aust.

Family Anthoceraceae Aneuraceae Bartramiaceae Bryaceae Cyathodiaceae Ditrichaceae Fissidentaceae Fissidentaceae Marchantiaceae Ricciaceae Ricciaceae Ricciaceae

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The CED (2003) study collected 530 species of higher plants from the major wetlands under study. For the purpose of this paper, the list was updated by including secondary data from various floristic studies carried out in these areas by Ramachandran and Nair (1988), Babu (1990), Vajravelu (1990), Sreekumar and Nair (1991), Joseph (1991), Rejani (1991), Mohanan and Henry (1994), Subramaniyan (1995), Sasidharan (1998), Sunil (2000) and Manju et al (2005). A total of 725 vascular plants, which include 8 Pteridophytes and 717 Angiosperms in 81 families were recorded from the wetlands studied, and the list is available with CED. The first ten dominant families are Cyperaceaae (115 species), Poaceae (83 species), Scrophulariaceae (46 species), Fabaceae (29 species), Asteraceae (22 species), Eriocaulaceae (17 species), Araceae, Convolvulaceae and Lythraceae (14 species each), and Commelinaceae (13 species). Out of the 725 plants listed, 503 species are seen only in wetlands and moist areas close to wetlands, whereas 222 species occur in the wetland areas as well as other areas (Table 3). In the wetland dependent category, herbs are the dominant group while trees dominate in the other group. Table 3. Habit wise distribution of wetland dependent and other species Category

Trees

Shrubs

Climbers

Herbs

Total

No.

%

No.

%

No.

%

No.

18

3.5

15

3

20

4

450

89.5 503 100

Plants seen in wetlands as well as other areas 85

38

48

22

45

20

44

20 222 100

Total

14

63

9

65

9

494

68 725 100

Wetland dependent species

103

%

No. %

The distribution of plants in different wetlands is given in table 4. Herbaceous species dominate in all wetland areas except in the unique Myristica Swamps of Kulathupuzha and Shendurney Wildlife Sanctuary (WLS). The composition and structure of the vegetation in a wetland is also influenced by changes to hydrology and soil salinity, catchment runoff and disturbance etc. As a whole, the coastal wetlands are rich in floristic diversity (Table 5). 281 species are common to coastal and inland wetlands. 237 species present in the coastal system are not seen in inland wetlands, and 207 species seen in inland wetlands are not present in the coastal wetlands.

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Table 4. No. of plant species in different wetlands No. Wetland

1

Total Trees Species

Shrubs Climbers Herbs Mangr

oves

Veli-Akkulam Estuarine complex

190

33

14

20

23

7

2

Ashtamudi Lake

256

31

19

25

181

11

3

Vembanad Kol wetland system

334

26

14

21

273

13

Mangalavanam Mangrove area 116

16

9

19

72

9

Puthuvypin Mangrove area

136

24

11

17

84

12

6

Thrissur Kol wetlands

187

4

7

10

166

—

7

Chetwai Mangrove area

156

29

12

16

99

8

8

Purathur estuary

140

26

9

10

101

5

9

Kadalundi Estuary

199

19

14

14

152

10

10 Kavvai-Kunhimangalam backwater system

180

37

8

9

126

11

11 Sasthamkotta Lake

131

21

10

10

100

—

12 Pookode Lake

164

15

19

9

126

—

13 Periyar reservoir

267

30

23

13

201

—

14 Malampuzha reservoir

178

16

9

7

146

—

15 Myristica swamps of Kulathupuzha and Shendurny WLS

160

63

26

27

44

—

4 5

Table 5. Distribution of species in different types of wetlands Distribution

Trees

Shrubs Climbers Herbs Total % to total species

Coastal wetlands

51

34

40

393

518

71

Inland wetlands

87

47

43

311

488

67

Both coastal and inland wetlands

35

18

18

210

281

39

Only in coastal wetlands

16

16

22

183

237

33

Only in inland wetlands

52

29

25

101

207

29

100

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DISCUSSION The wetlands of Kerala are rich in floristic diversity. Despite their fundamental importance to aquatic ecosystems, relatively little research has been directed towards aquatic and wetland plants, especially in riverine environments. Consequently, little is known of the ecological and life history requirements of many species. The only comprehensive aquatic flora survey available in Kerala was by Joseph (1991). The study, mainly concentrated on the inland wetlands, of Malabar region and described only 241 species of angiosperms belonging to 42 families. The present investigation is an attempt towards exploring the floristic wealth of Kerala wetlands. However, at present, the study does not include many natural small ponds and streams of the State, which are supposed to be rich in floristic biodiversity. The streams are rich in plants belonging to the family Podostemaceae which is considered to be the fourth largest aquatic plant family of Kerala, with 19 species, of which only 4 species were located in the present study area. The family Eriocaulaceae, with 37 wetland species so far recorded from the State is also not well represented in the present study area. The phytoplanktons and lower groups of macrophytes were also not included in the study. Still, the study could identify a good number of macrophytes, especially Angiosperms, from the major wetlands of Kerala. The present study included both inland and coastal wetlands from Thiruvananthapuram to Kannur and listed 503 true wetland species. CONCLUSION Aquatic ecosystems and wetlands are usually looked down upon as wastelands and are being reclaimed for various developmental needs, bringing several taxa, which would be of great potential value in medicine and other industrial uses, to the verge of extinction. The encroachment, mining and reclamation in many locations lead to loss of biodiversity as well as changes in the ecosystem functioning. Loss of wild species, including endemic species, is a phenomenon associated with ecosystem changes. Mangroves are the most affected ones throughout the coastal reaches of Kerala from south to north. Loss of the world’s wetlands poses an increasing problem because of loss of important, ecological and economic values, perhaps irreversibly, when natural wetland is transformed or degraded. Role of biodiversity in supporting the wetland system and its resilience are not well known; however, the values offered by many wetland systems to human society are extremely important. Although difficult to estimate, the total life support function of wetlands may be particularly significant, as wetland comprises a diverse range of marine, coastal, estuarine and freshwater habitats. In spite of the fairly large volume of work carried out on the various aspects of wetlands of Kerala, there is no public repository of data and summary embodied in the documents. There is a great need for inventorying the aquatic and wetland taxa in Kerala, especially in the face of the rampant habitat destruction that is taking place. The presently available Centre for Environment and Development

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floristic diversity studies on wetlands of Kerala, especially with regard to the phytoplanktons are mainly concentrated on the three Ramsar sites and some other major sites. Similarly, there is no account of most of the Pteridophytes, Bryophytes etc which are wetland dependent. The degree of endemism in wetland areas is barely touched upon. So also there are no accounts on the vulnerability of species and status of medicinal plants and traditional knowledge systems attached to the wetland plants. There are reports of many plants being used as water purifiers in ponds and wells in many places. Considering the above situation, the study recommends initiation of the following research programmes with respect to the floristic diversity of the wetlands of Kerala: Detailed floristic inventory counting all groups of plants and preparation of checklists of species with distribution, vulnerability-status and economic value Detailed study on the degree of endemism in wetland flora of Kerala Content and status of traditional knowledge system associated with the wetland flora. REFERENCES Abdul Hameed, C., Rajesh, K.P. and Madhusudhanan P.V. (2003). Filimy ferns of South India. Penta book publishers and distributors, Kozhikode. Adamus, P.R. (1996) . Bioindicators for Assessing Ecological Integrity of Prairie Wetlands. EPA/600/R-96/082. Corvallis, OR. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division. Anupama, C. and Sivadasan, M. (2004). Mangroves of Kerala, India. Rheedea, 14: 09-46 Babu, A. (1990). Flora of Malappuram District (excluding Nilambur forest division). Ph.D. Thesis, University of Calicut. Barrett, S.C.H., Eckert, C.G., and Husband, B.C. (1993). Evolutionary processes in aquatic plant populations. Aquatic Botany 44: 105–145. Best, E.P. (1988). The phytosociological approach to the description and classification of aquatic macrophyte vegetation. In Vegetation of Inland Waters. J.J. Symoens, Ed. pp. 155–182. Dordrecht. Kluwer Academic Publishers. Brinson, M.M. (1993). A Hydrogeomorphic Classification for Wetlands. Technical Report WRP-DE-4. Washington, D.C. U.S. Army Corps of Engineers. Britton, R.H. and Crivelli, A.J. (1993). Wetlands of southern Europe and North Africa: Mediterranean wetlands. In Wetlands of the World I: Inventory, Ecology and Management. D.F. Whigham, D. Dykyjova, and S. Hejny, Eds. pp. 129–194. Dordrecht. Kluwer Academic Publishers. Carlisle, B.K., Hicks, A.L., Smith, J.P., Garcia, S.R., and Largay, B.G. (1999). Plants and aquatic invertebrates as indicators of wetland biological integrity in Waquoit Bay watershed, Cape Cod. Environment Cape Cod 2: 30–60. Carpenter, S.R. and Lodge, D.M. (1986). Effects of submersed macrophytes on ecosystem processes. Aquatic Botany 26: 341–370. 102

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CED (2003). Survey and Inventory of wetlands of Kerala for conservation and sustainable management of resources. Project Report, Kerala Forest Department, Thiruvananthapuram, Kerala. Chand Basha, S. (1992). Distribution of Mangroves in Kerala. Ind. Journ. Mar. Sci., 117 (6):439 – 448. Cook, C., D., K. (1990). Aquatic plant book. SPB Academic Publishing, Netherlands. Cowardin, L.M., Carter, V., Golet, F.C. and La Roa E.T. (1979). Classification of Wetlands and deep water habitats of the United States fish and wild Life Service. FWS/ OBS – 79/31, Washington DC. Cronk, J.K. and Mitsch, W.J. (1994). Periphyton productivity on artificial and natural surfaces in four constructed freshwater wetlands under different hydrologic regimes. Aquatic Botany 48: 325–342. Gersberg, R.M., Elkins, B.V., Lyon, S.R., and Goldman, C.R. (1986). Role of aquatic plants in wastewater treatment by artificial wetlands. Water Resources 20: 363–368. Gosselink, J.G. and Turner, R.E. (1978). The role of hydrology in freshwater wetland ecosystems. In Freshwater Wetlands — Ecological Processes and Management Potential. R.E. Good, D.F. Whigham, and R.L. Simpson, Eds. pp. 63–78. New York. Academic Press. Joseph, K.T. (1991). Observations on the Aquatic Angiosperms of Malabar (North Kerala). Ph.D. thesis, University of Calicut. Joseph, K.T. (2002), Flora of wetlands. In: M. Jayakumar (eds.) Wetland conservation and management in Kerala. KSCSTE, Thiruvananthapuram, Kerala, pp. 69-84. Mack, J.J., Micacchion, M., Augusta, L.D., and Sablak, G.R. (2000). Vegetation Indices of Biotic Integrity (VIBI) for Wetlands and Calibration of the Ohio Rapid Assessment Method for Wetlands. Grant CD95276. Final Report to U.S. Environmental Protection Agency. Columbus, OH. Ohio Environmental Protection Agency, Wetlands Unit, Division of Surface Water. Manju, C. Nair, Rajesh, K.P. and Madhusudhanan P.V. (2005). Bryophytes of Wayanad in Western Ghats. Malabar, Natuaral History Society, Kozhikode. Manilal, K.S. and Sivarajan (1975). A contribution to the study of Hydrophytes of Kerala. Proc. Nat. Acad. Sci., 45 (4): 225-231. Mohanan M. and Henry A.N. (1994). Flora of Thiruvananthapuram. Botanical survey of India, Calcutta. Mohanan, .N. (1999). Mangroves. In: Thambi, K.B., Nayar, N.M., and Nair, C.S. (Eds.), The Natural Resources of Kerala. WWF India, Thiruvananthapuram, pp, 149-158. Nayar, B.K. and Geevargheese, K.K. (1993). Fern flora of Malabar. Indus Publications, New Delhi. Panfish Book (2002). Master Panfish Book. Department of Fisheries, Vikas Bhavan, Thiruvananthapuram, Kerala. Centre for Environment and Development

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Peverly, J.H., Surface, J.M., and Wang, T. (1995). Growth and trace metal absorption by Phragmites australis in wetlands constructed for landfill leachate treatment. Ecological Engineering 5: 21–35. Rajeevan, B. (1990). Studies on the Bryophytes of Idukki District. Ph.D. Thesis, Bharathiar University, Coimbatore. Rai, U.N., Sinha, S., Tripathi, R.D., and Chandra, P. (1995). Wastewater treatability potential of some aquatic macrophytes: removal of heavy metals. Ecological Engineering 5: 5–12. Ramachandran, K. K., Mohanan, C. N., Balasubrahmonian, G., Kurien, J. and Thomas, J. (1986). The Mangrove Ecosystem of Kerala: Its mapping, inventory and some environmental aspects. (Unpublished Interim Report 198586). Centre for Earth Science Studies (CESS), Thiruvananthapuram, Kerala. Ramachandran V.S. and Nair V.J. (1988). Flora of Cannanore District. Botanical survey of India, Calcutta. Raveendran, K. (2003). Diversity of marine fungi of Kerala coastal water. Abstract on National symposium on prospecting of fungal diversity and emerging Technologies Pune. pp 24. Reddy, K.R., D’Angelo, E.M., and DeBusk, T.A. (1989). Oxygen transport through aquatic macrophytes: the role in wastewater treatment. Journal of Environmental Quality 19: 261–267. Rejani, A. (1991). Taxonomy of Cyperaceae of Kerala. Ph.D. thesis, University of Calicut Santhosh Namby and Madhusudhanan P.V. (1998). Fern Flora of South India: Polypodioid Ferns. Daya publishing Company, Delhi. Sasidharan, N. (1998). Studies on the flora of Periyar Tiger Reserve. KFRI Research Report No. 150, Kerala Forest Research Institute, Peechi, Thrissur. Sculthorpe, C.D. (1967). The Biology of Aquatic Vascular Plants, 610 pp. London. Edward Arnold Publishers. Shobha.V, P.Ignatious Miranda, 1987. Nature of plankton products in Kadinamkulam Lake and Astamudi estuary of Kerala. Proceedings Natural seminar on management, TVM- 307-312 Sreekumar, P.V. and Nair, V.J. (1991). Flora of Kerala - Grasses. Botanical Survey of India, Calcutta. Subramaniyan K.N. (1995). Flora of Thenmala forest Division. International Book distributors, Dehradun. Subramaniyam, R. and Sarma, V. (1967). Studies on the phytoplanktons of west coast of India, Part IV: Magnitude of the standing crop for 1955-62 with observations on nanoplanktons and its significance to fisheries. J. Mar. Biol. Ass. Ndia, 7: 319-406 Sunil, C.N. (2000) Studies on flowering plants diversity of Alappuzha District, Kerala. Ph.D. thesis, University of Calicut. 104

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Tanner, C.C., Clayton, J.S., and Upsdell, M.P. (1995a). Effect of loading rate and planting on treatment of dairy farm wastewaters in constructed wetlands. I. Removal of oxygen demand, suspended solids and faecal coliforms. Water Resources 29: 17–26. Tanner, C.C., Clayton, J.S., and Upsdell, M.P. (1995b). Effect of loading rate and planting on treatment of dairy farm wastewaters in constructed wetlands. II. Removal of nitrogen and phosphorus. Water Resources 29: 27–34. Thressiamma, M. and Nair, N.B. (1981). Phytoplankton of the Veli Lake - A lagoon on the south west coast of India. Mahasagar, 14: 48 - 54. Tiner, R.W. (1991). The concept of a hydrophyte for wetland identification. BioScience 41: 236–247. Tiner, R.W. (1999). Wetland Indicators: A Guide to Wetland Identification, Delineation, Classification and Mapping, 392 pp. Boca Raton, FL. CRC Press. Unnithan, V. K, Bijoy Nandan, S. and Vava, C.K. (2005) Fisheries and environment assessment in selected backwaters on the south west coas of India. Bulletin No. 139, Central Inland Fisheries Research Institute, Barrackpore, Kolkata. U.S. Army Corps of Engineers (1987). U.S. Army Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1. Vicksburg, MS. U.S. Army Corps of Engineers, Environmental Laboratory, Waterways Experiment Station. Warming, E. (1909). Oecology of Plants. An Introduction to the Study of Plant Communities. Oxford. Clarendon Press (updated English translation of 1886 text). Watzin, M.C. and Gozzelink, J.G. (1992). The Fragile Fringe Coastal Wetlands of the Continental United States. Louisiana Grant College Program, Louisiana State University, Baton Kange, LA; U.S. Fish and Wildlife Service, Washington, DC and National Oceanic and Atmospheric Administration, Rockville. Wiegleb, G. (1988). Analysis of flora and vegetation in rivers: concepts and applications. In Vegetation of Inland Waters. J.J. Symoens, Ed. pp. 311–341. Dordrecht. Kluwer Academic Publishers.

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