THE FLORISTIC WEALTH AND DIVERSITY OF MYRISTICA SWAMPS, THE FRAGILE FRESH WATER ECOSYSTEM OF WESTERN GHATS.

fragmentation. The floristic diversity indices and floristic composition and community status of Myristicaceae members are also vary with vegetation succession due to changes in the selective recruitment and changes in the functional dynamism. The present investigation highlighting the floristic wealth and diversity of myristica swamps of Kerala with respects to their salient conservational features. diversity indices were assessed by laying quadrate of size 15 x 10m in randomized way and pooled to get the primary and secondary vegetation data. The data were analysed for Species richness (Mergalef, 1958), Important Value Index (Barbour et.al., 1974) Species evenness (Pielou, 1975)Floristic diversity indices (Shannon Weiner, 1963; Simpson, 1949), Species distribution(Whiteford, 1948; Curtis and McIntosh, 1958) and Biological spectrum(Raunkiaer, 1934).

918 arnottiana, Syzygium travancoricum, Vateriaindicaetc are the common associate species. It is observed that, all the swamps are under ecological succession due to anthropogenic or natural reasons and vegetation have been exploited which in turn is obviously in the path of extinction due to multiphase development and subsequent fragmentation. The floristic diversity indices and floristic composition and community status of Myristicaceae members are also vary with vegetation succession due to changes in the selective recruitment and changes in the functional dynamism. The present investigation highlighting the floristic wealth and diversity of myristica swamps of Kerala with respects to their salient conservational features.
Copy Right, IJAR, 2018,. All rights reserved ……………………………………………………………………………………………………… Introduction:- The Myristicaswamp isphysio-geographic feature of low laying areas of the Western Ghats with evergreen forest vegetation coming under the category 4C/FSI (Champion and Seth, 1968).The vegetation is characteristic with swampy adaptive nature like recalcitrant seeds,etiolate seedlings with scale leaves, knee roots or perennial rhizomes. The four storiedvegetation isphanero-geophyticdominantly represented by members of Myristicaceae, Araceae,Zingiberaceae,Flacourtiaceae, Dipterocarpaceae, Arecaceae. The community status of the Myristicaceae members are structurally and functionally dominant over other members and hence the name Myristica swamps. In 1960,Krishnamoorthy first time reported this rare forest type from Kulathupuzha region of Trivandrum Forest Division. There after these swamps were identified and floristic enumeration was carried out from different States along the Western Ghats viz.Karnataka (Saldanha, 1984;Gadgil &Chandran, 1998;Chandran &Gadgil, 1998;Chandran&Mest, 2001;Vasudeva et al., 2001), Goa (Santhakumaran et al., 1995(Santhakumaran et al., , 1999 and Kerala (Pascal, 1984; A.G. Pandurangan, 2004;Vijayakumar, 2007;Rajendraprasad, 2015). In Kerala, this rare ecosystem and relic vegetation is located and identified with sacred grooves; the conserved forest patches in the middle of urbanization on religious ground or social belief (Rajendraprasad, 2015). This unique vegetationinclude many endemic members and red listed plants (Bourdillon, 1908;Sasidharan& Sivarajan, 1996;Ramesh & Pascal, 1997;Chandran&Mest, 2001;Nayar& Sastry, 1987). Hence the Myristica swamp, the only fresh water swamp of the Western Ghats with pristine vegetation forms the virtually live museum of ancient life formsof great biological interest. In Kerala, traditional landscapes are changing like evergreen forests changes into paddy fields or plantation of areca, coffee, rubber or drowned due to irrigation project or extermination due to forest fire. All these reasons have adverse impact on myristica swamps also (Krishnamoorthy, 1960). The existing swamps are heading towards extinction due to developmental and urbanization pressure followed by the fragmentation and isolation leads to the change in vegetational composition and ecological functioning (Rajendraprasad, 2016).Since the swamps being the edaphic formation and members are with adaptive traits, the floristic diversity is moderate with aggregate distribution and characterized with low species richness and species evenness. The present study envisaged the structural, functional and vegetational characterization of freshwater, Myristica swamp ecosystem, probably the most ancient forest type of the Western Ghats left behind with a history more than 140 million years (Chandran et al, 1999). Hence swamp forest has to be protected and conserved through careful planning and management to avoid the extinction of rare ecosystem and its adaptive floristiccomposition.

Material and Methods:-
Regular field explorations were carried out to selected Myristica swamps distributing in 8 districts of Kerala during 2015 -2017 covering different seasons for enumeration and analysis of floristic composition.Regional floras were used in authenticating the taxonomic identification and status of the plants were fixed using IUCN Red List. The phytosociological features and floristic diversity indices were assessed by laying quadrate of size 15 x 10m in randomized way and pooled to get the primary and secondary vegetation data. The data were analysed for Species richness (Mergalef, 1958), Important Value Index (Barbour et.al., 1974) Species evenness (Pielou, 1975)Floristic diversity indices (Shannon Weiner, 1963;Simpson, 1949), Species distribution (Whiteford, 1948;Curtis and McIntosh, 1958) and Biological spectrum (Raunkiaer, 1934

Result and Discussion:-
The fresh water swampy vegetation is unique in bio wealth and diversity, and are restricted to a very narrow ecoregion. These forest lands have been exploited and obviously are in the path of extinction due to multiphase development and urbanization.The freshwater swamp ecosystem was first reported from Travancore region of southern Western Ghats and had an extended area of 2000 ha. and now only small remnants of this ecosystem are found within an area of 150 ha. (Vijaya Kumar. et al. 2007). The existing one are also highly fragmented and isolated with nature and manmade reasons which leads to change in the structural composition and ecological functioning. All these have leads to fragmentation and isolation of these fragile and unique ecosystems. The fragmentation involves dividing up of continuous ecosystem into smaller patches and the functional dynamism is affected with changes in the floristic, ecologic and edaphic reasons. The species richness of Myristica swamp is very low when compared to other forest types. The low value for species richness is account by the prevailing edaphic conditions and ecological requirement of swampy species. The floristic diversity, irrespective of the size of myristica swamp, shows low value when compared to other ecosystems of Western Ghats. The average Simpsons index value is 0.74, Shannon Weiner index is 2.71. The variety ratio of the myristica swamp is 0.137, and thevalue for equitability is 0.79 and that of Species richness is 1.29. The relative occurrence and community status of Myristica fatua and Gymnacranthera canarica in terms of IVI are very high and above the normal hence considered as specialist species compared to other swampy species, generalist species. The community status of non-swampy species is very low and being considered as associate species (Table  1).

The Community Status of Important Tree species of Myristica swamps
The dominant family isFabaceae with highest number of species. Nearly 25.3% of species belonged to this family followed by Rubiaceae (20.48%), third dominant family is Araceae consisting of (16.86%) other dominant families as follow: Euphorbiaceae (8.43), Lauraceae (8.43), Oleaceae (8.43), Zingiberaceae (8.43) (fig 1). Plant diversity in different stages of succession is inincreasing trend, observed towards the advancement of successions. The initial establishment is due to edge effect, change in the environmental parameters, causing the decline in population ofMyristica fatua and Gymnacranthera canarica and increase in number and IVI value ofnon-swampy species, generalist and associate species.
With regard to representation of various distributions level in the flora of Myristica swamps 36% of taxa shows random distribution, 6% are regular and 58% species shows aggressive distribution pattern (Fig. 2). Structurally the swamp is dominated with tree forms (70%) followed by geophytic(11%) and chamaephytes(9%). The Lianas (5%) and therophytes(5%) are remaining members which considerably control the physiognomy of the swamps.The different structural forms occupy different space with different association having different boundaries, each with a varying degree of uniformity in structure and composition. The distribution of first storied trees and entangled lianas are responsible agents of controlling micro climate and micro niche of the ecosystem (fig 3).

Conclusion:-
The Western Ghats in Peninsular India is one among the biodiversity hot spots in the world and one of the three endemic hot spotsof India. It stands foremost in the representation of endemic elements in the Indian flora. The flora of Myristica Swamps shows high degree of endemism.In 1992,Panwaret al highlighted the vegetation and most critically needing conservation. The Swamp vegetation is edaphic formations with physio-geographic features of low laying area of Western Ghats resulting from the hydro and geomorphic peculiarities. The swamp supports characteristic amphibian evergreen vegetation with the specialist and generalist species; dominated with Myristicaceae family. The specialist members are structurally modified to overcome the seasonal flooding. The floristic diversity and species richness is always lower than other forest types of Western Ghats, indicating the specific edaphic and ecological requirements of these species, habitat specialization which permits only adaptive species to survive in swampy area. Again the vegetation is with high percentage of endemism. The swamp inhabiting threatened specialist species like Myristica fatua var. magnifica and Gymnacranthera canarica population are declining during the advancement of ecological succession. The fragility of ecosystem and unique biota invite the immediate alternative of the conservation strategies required to protect the existing swamps.