Forest cover has declined between 1972 and 1985 at a rate of over 2.4% annually, paralleling that for India as a whole. Extrapolation from 1986 to 1989 means a total loss of almost 34% for 1972 to 1989. Only 6.8% of original extent of vegetation exists today (Myers et al., 2000).
Substantial changes in vegetation in areas like Tenmalai region over a considerably long period have resulted in extensive alterations in landscape profiles leading to changes in insect biodiversity with loss of specific-mix of insect species and their community organization.
Impact of disturbances in Tenmal region of Western Ghats has been examined in relation to hitherto-well-explored thrips faunal complexes as well as of other insects in insect floor (Ananthakrishnan, 2000). Recently Nagendra and Gadgil attempted a broad seal mapping (at a 1:1000, 000 scales) of Western Ghats into different landscape type using IRSIB imagery.
They used Normalized Difference Vegetation Index (NDVI); which reduces problems of scene to scene radiometric variability. This index is believed to be correlated to vegetation biomass, vigor, photosynthetic activity and leaf area index and is potentially useful for classifying different types of vegetation.
They interpreted the distribution of eleven landscape types in term of topography, climate, population, agriculture and vegetation cover.
A total area of 170,000 sq. km. along west coast and Western Ghats of India was classified into 14 vegetation types using the 4 moments of distribution of the NDVI. A total of 205 patches belonging to 11 classes were recorded.
Less than 15% of Western Ghats is protected in 20 national parks and 68 sanctuaries Considering IUCN categories I-IV, which offer a higher level of protection, the figure drops to around 11%, according to World Database on Protected Areas.
To ensure proper conservation of biodiversity in protected areas network, identification and conservation of “Key Biodiversity Areas” (KBAs) is required. Preliminary data on important Bird Areas compiled by Bombay Natural History Society, data on globally threatened species of mammals, birds, and amphibian” plants, and to a lesser extent, reptiles and fish were analyzed to identify and delineate 126 KBAs. Landscape-scale action, through biodiversity conservation corridors, will be necessary for wide ranging species like Asian Elephant, tiger, Asiatic Wild dog and greater spotted eagle.
Common floral species in both hot spots include Ternstroemia japonica, Rhododendron arboretum, Hypericum hookerianum, Thalictrum javanicum, Cotoneasterbuxifolia, Parnassians hightiana, Lonicera ligustrina and Symposia lauriana.
Amongst fauna, the Himalayan and Nilgiri Tahr. Nilgiri Pine Marten, laughing thrush, Bicornis homrai, Batrachostomus hodgsoni hodgsoni, Irena puella, Accipter spp. and Lophotriorchis kienerii are found in both regions (Khoshoo, 1996). A plausible ex explanation for presence of common species is that they were both pleistocene relict.
Others however feel that any floral and faunal resemblance between two is due to convergent evolution. Out of 25 “Hot Spots” worldwide, India has Eastern Himalayas and Western Ghats. Indian Hot Spots contain 5,332 endemic higher plant species, mammals, reptiles, amphibian and butterflies (WCMC, 1993).
Out of 163 globally threatened species including Rhinoceros unicornis, Bubalus bubalis and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrates and 36 plant species are found. Endangered dragonfly (Epiophlebia laidlawi) is found here. Tylototriton verrucosus is found within Indian limits (Prater, 1971). Angiosperm families recorded include Magnoliaceae. Degeneriaceae, Himantandraceae, Eupomatiaceae, Wineraceae, Trochodendraceae, Tetracentraceae, and Lardizabaleaceae.
Primitive genera are Alnus, Aspidocarya betula, Decaisnea, Euptelea, Exbucklandia, Haematocarpus, Holboellia, Houttuynia, Magnolia, Mangelietia, Pycnarrhena and Tetracentrol (Malhotra and Hajra, 1977).
Udvardy (1975) proposed 14 biogeographically biomes in the world. Olsen et al., (1983) recognized 8 broad groups subdivided into 46 ecosystems throughout world. Holdridge (1967) recognized 7 life zones and 25 ecosystem types within these 7 zones. Hotspots are areas of high conservation value that are facing significant threats to conservation (Myers, 1988). Woinarski et al., (1966) has argued to conserve representative of all major habitats. The best strategy for preserving species richness is to consider endemism and type of habitat.
India possesses rich endemic and economically important biological wealth. Many medicines have a biological origin. There are over 100,000 protected areas worldwide, covering over 12% of the Earth’s land surface.
The importance of protected areas is reflected in their widely accepted role as an indicator for global forests and environmental assessments. The numerical, spatial and geographic attributes of protected areas can be further enhanced by investigation of the biodiversity coverage of these protected areas (Chaps et al., 2005). IUCN has recommended protecting >10% of every biogeography region (Reid, 1988).