|Theme: 5. Flora—Trees, Shrubs, Herbs, Orchids, Medicinal Plants||Paper 1 | Paper 2 | Paper 3|
STUDIES ON WETLAND FLORA OF UTTARA KANNADA
Rao G R, Divaker K Mesta, M D Subas chandran, and T V Ramachandra
Uttara Kannada with its luxuriant tropical climate coupled with heavy rainfall harbors large number of wetlands which are habituated by diverse kinds of wetland plants. These wetland plants which may be aquatic, semiaquatic or on moist soils grow in diverse kind of habitats. Different localities were selected throughout the district and studied for their species composition, diversity, richness across different habitats, families etc. Many wetland plants are endemic and endangered having many economical uses such as medicinal, food, and other uses.
Wetland can be defined as the place where 80 % are more of the plants growing there are wetland plants. Uttara Kannada district enjoys a tropical climate with heavy monsoon showers. Hence during rainy seasons most places such as grasslands, fields, wastelands etc. will be inundated by water. Many ditches and small puddles are created which hold water for some months due to continuous rain. Both permanent water bodies such as lakes, rivers and large ponds etc., and temporary areas such as laterite bogs, puddles etc., harbors large number of plants which require ‘wetness' of habitat for various period. Hence we have included the plants coming up in all monsoon inundated places, either temporary or permanent, and also wet soils which are not water logged. Plants confined to marine and highly brackish waters are excluded.
Plants growing in wetlands and other moist soils may either be annuals or perennials. Many of the smaller and slender herbs are annuals. They flower, fruit, and disperse seeds, and die in a single year. However perennials perennate for many years developing food storing woody structures such as rhizomes, corms, stolons etc.
There have been many attempts to classify aquatic plants according to their growth forms. Cook (1990) summarized them and suggested a classification based on the response of the plant to milieu for growth and development rather than directly on its morphology or the way it survives adverse conditions (Cook.C.D.K, 1996). According to this the different types of growth forms are:
Ephydates- Bottom-rooted with floating leaves.
Haptophyte- Attached to but not penetrating the substrate.
Hyperhydate-Emergent aquatics (lower parts almost always in water).
Plankton- Free swimming below the water surface.
Pleustophyte-Free-floating (at the water surface).
Rosulate-Submerged, bottom rooted, leaves in a rosette.
Tenagophyte- Juvenile submerged, adult usually terrestrial.
Vittate- Submerged, bottom rooted, leaves cauline.
However many species change their dependence on water in regions with different climates or with different hydrological regimes. Such plants can have more than one life forms.
2. STUDY AREA
The Uttara Kannada District sea board lies between 74 0 9' to 75 0 10' east longitude and 13 0 55' to 15 0 31' north latitude. The district has three main and distinctive regions: the coastlands, the Sahyadrian, and eastern margin where the table land begins. The relief and climate have introduced these regional differences. The 4 leading rivers, the Kalinadi in the north, the Bedthi or Gangavali about 32 km south, the Aghanashini or Tadri and the Sharavathi about 24 km south of the Tadri, and the smaller Venkatapura river and few rivulets like the Varada, Belekeri, Ankola, Gorgadde halla and the Bhatkal or Sharabi create many wetland habitats both temporary and permanent. Apart from these wetland systems, large number of other wetlands such as lakes, reservoirs, ponds, puddles, lateritic bogs, wet grasslands, marshes, swamps dot the district harboring large number of wetland plants.
Table 1: Wetland study localities in Uttara Kannada
|7||Kathlekan swamps (Siddapur)|
|12||Bramur-Nagur cross (Mirjan)|
3. MATERIALS AND METHODS
The survey was a random opportunistic survey visiting 29 different wetland localities in 9 taluks of Uttara Kannada. Some of the plain area taluks are not studied here. In each wetland, plants were collected coming in different wetland zones such as deep waters, shallow water, fringes, and other nearby moist soils around the wetland. Rare and unidentified specimens were pressed for herbaria using dry method. Photographs and geographical co-ordinates of occurrence using Global positioning system (GPS) were noted. Fresh specimens were identified with the help of regional and other floras.
4. RESULTS AND DISCUSSION
A total of 167 species from 32 families were identified from the 29 localities distributed in 9 taluks. Schoenoplectus lateriflorus was the most widely occurring species in a total of 16 localities followed by Cyperus halpan , Geissaspis cristata . Cyperus halpan has 2 sub species C. halpan subsp. halpan and C.halpan subsp. juncoidesI (Figure 1). Species of Schoenoplectus and C.halpan are found in shallow temporary waters, fringes of permanent water bodies and in slow running streams. G.cristata occurred mostly in wet soils along the marshes, ponds and river banks and hence common in many localities. These were associated with species of Lindernia , Fimbristylis , Eriocaulon etc. More deeper water was mostly harbored by species of Nymphea , Nymphoides and other rooted floating species.
Figure 1: Widely occurring species (for species id see table 2)
Table2: Species name with species id
Cyperaceae had the highest number of species (50) while other species followed as shown in Table 3 . This is also seen the total species count of all species in a family in different localities. Here also Cyperaceae had a highest of 182 species count in different localities followed by other families. This shows the importance of Cyperaceae members in wetland ecosystem. Scrophulariaeae, Poaceae, and Eriocaulaceae also have a higher species diversity and count. However many of their species are not restricted only to wetlands, but also to nearby moist soils also.
Table 3: Family wise species count in different localities
|No.||Family||Total no of species||Species count in different localities|
Figure 2: Different localities ID and their species number. (For localities see in Table 1)
Ragihosahalli of Sirsi taluk had the highest number of species diversity with 33 species followed by Shirali of Bhatkal with 32, Haldipur of Honnaver and Hosur of Kumta with 28 species each. Except Ragihosahalli most of the coastal taluks had large fresh water marshes hence showed high species diversity compared to higher altitude lands such as Watehalla, Kathlekan, Yellapur etc.
Table 4: Number of Annuals or Perennial species
Nearly 97 species are annuals showing the temporary nature of the wetlands. In some of the permanent wetlands 42 perennial species were seen. Many fall in between these two categories (annual/perennial) and can be either of the two according to the wetland systems. Some of the annuals may also show tendencies towards perenniality if the wetland is permanent.
Table 5: Wetland plants Endemic to Western Ghats and India
There are 17 endemic plants to India , in which many are endemic to Western Ghats . Eriocaulaceae had the highest number of endemics (Table 5) Weisneria triandra is also an endangered species found mostly in lateritic bogs of coastal areas.
Table 6: wetland plants of Medicinal value
|Sl. no.||Wetland species||Family|
|14||Cyperus rotundus ssp.rotundus||Cyperaceae|
Many of the specis such as Cyperus rotundus, Spilanthes paniculata, Ammannia baccifera , etc., as shown in Table 6 have high medicinal value. They are regularly collected by the village medicine practitioners for local use.
Table 7: Species with other uses
|Sl. no.||Wetland species||Family|
|4||Cyperus rotundus ssp.rotundus||Cyperaceae|
Plants such as Alternanthera sessilis, tubers of Colocasia esculenta, Eleocharis dulcis are eaten as vegetables, Cyperus iria, C.pangorie, Fimbristylis dichotoma are used in making mats ( Table 7 ).
Wetlands have a large diversity of plants needing wetness of varying degrees. These plants are accordingly adapted to the local availability of water and many show transition between annual and perennialness and also their type of growth forms. Large wetlands are found in the district catering for the needs of both plants and humans. With rapid rapid urbanization and other land use wetlands are rapidly dwindling in number and size. Hence wetlands such as lakes, streams, ponds (small or big), bogs, marshy grasslands etc., have to be conserved and managed sutainably for welfare of both wetland plants and man.
We thank Mr. Sameer Ali, Mr. Vishnu D Mukri, Mr. Lakhsminarayana, and Mr. Shrikanth Naik for their assistance in field data collection, herbaria preparation, etc.
Energy & Wetlands Research Group,
Centre for Ecological Sciences,
Indian Institute of Science,
Bangalore 560 012