FLORISTIC DIVERSITY IN WESTERN GHATS : DOCUMENTATION , CONSERVATION AND BIOPROSPECTION – A PRIORITY AGENDA FOR ACTION

Western Ghats, being one of the global hotspots of biodiversity, supports an enormous vegetal wealth, which over the years is undergoing great stress due to anthropogenic disturbances. This region which forms the “Malabar Botanical Province” according to phytogeographers is a narrow stretch running from the hills south of Tapati river in the north to Kanyakumari in the south along the west coast of India covering the states of Goa, Maharashtra, Karnataka, Tamil Nadu and Kerala. The narrow stretch of Western Ghats running approximately 1500 km encompasses a considerable gradient of climatic conditions which have resulted in the development of diverse forest types ranging from the dry scrub types to the semi-evergreen and evergreen forests. Details of these forest types and their floristic composition are discussed. The development of the tropical rain forests in the southern Western Ghats and the ‘sholas’ in the Nilgiris region are the most outstanding features of Western Ghats. The entire Western Ghats biogeographic region is a major genetic estate with an enormous biodiversity of ancient lineage. Nearly 5800 species of flowering plants occur here of which 56 genera and 2100 species are endemic. Karnataka alone harbours 3900 species belonging to 1323 genera and 199 families while Nilgiris have 2611 species of flowering plants. Some dominant families are Poaceae, Leguminasae, Orchidaceae, Acanthaceae, Euphorbiaceae, Asteraceae, Lamiaceae and Rubiaceae. Analysis of endemic species reveals that Western Ghats being much older in age compared to Himalayan mountains, support a large majority of relict or palaeoendemics. Another unique feature of the endemic flora of Western Ghats is the prevalence of monotypic genera such as Adenon, Calacanthus, Polyzygus, Erinocarpus, Frerea, Griffithella, Haplothismia, Jerdonia, Lamprochaenium, Nanothamnus, Wagatea and Willisia. Some of the arborescent genera having maximum endemic taxa are Memecylon (16 spp.), Litsea (15 spp.), Symplocos (14 spp.), Cinnamomum (12 spp.), Syzygium (11 spp.), Actinodaphne (9 spp.), Glochidion (9 spp.), Grewia (9 spp.), Diospyros (8 spp.), Dalbergia (7 spp.), Hopea (6 spp.), Drypetes (6 spp.), Poeciloneuron (2 spp.), Blepharistemma, Erinocarpus, Meteoromyrtus, Otonephelium and Pseudoglochidion. The latter five genera are again monotypic. The flora of Western Ghats, particularly southern W. Ghats shows close affinity with the flora of Sri Lanka, supporting the view that Sri Lanka was connected to South India during the geologic past. Some important species common to both regions are listed. Agasthyamalai hills, Anamalai ranges, Nilgiris and the Palni hills are the hyperdiversity areas in Western Ghats which are also the hotspots pockets. The Western Ghats region is also a rich germplasm center of number of wild relatives of our crop plants such as the cereals & millets, legumes, tropical & sub-tropical fruits, vegetables, spices & condiments and a few others. Species of Piper, Oryza, Myristica, Elettaria, Amomum, Zingiber, Phaseolus, Vigna, Atylosia, Cinnamomum and Curcuma show great variability in southern Western Ghats. The alarming rate of loss of biodiversity in Western Ghats is a major concern today. Shifting cultivation, grazing, indiscriminate lopping, extraction of timber and fuel wood, spread of invasive alien weeds, recurrent forest fires and selective removal of certain species such as the medicinal plants have all resulted in severe destruction of the virgin forests which now survive only as pockets in the mountains summit areas. The accelerated population growth followed by expansion of agriculture, introduction of plantation crops like tea, coffee, rubber have resulted in the extermination of many taxa, endangering a number of economically important timber and other species. Discussing the major strategies for conservation, the author prioritizes certain issues for urgent action. Inventory of base line data and development of computerized databases, assessment of genetic diversity at least in wide spread taxa, identifying and conserving and monitoring the hotspot pockets of biodiversity (19 such sites are identified by the author), protection of sacred forests and special habitats, establishment of gene bank/seed bank, conservation of critically endangered species are some issues suggested for action. Discussing the utilization and management of the bio resources of Western Ghats, the author outlines the immense opportunities for Bioprospection, particularly chemoprospecting in wild medicinal and aromatic plants, which is much neglected. Recent developments in molecular biology and biotechnology have made it possible to scan the biodiversity for molecules with potential for commercial application. Problems and prospects associated with the bioprospection of the floristic diversity are discussed. Finally, the author calls for urgent attention for generating the trained manpower in taxonomy for shouldering this big responsibility of inventorization and conservation of the rich biodiversity of Western Ghats.