HOT SPOTS IN INDIA
India has two of the 25(Around the world, at least 25 areas qualify under the definition of Hotspot, with nine others possible candidates.) identified 'hot spots'. These are : Eastern Himalaya and Western Ghats.
Eastern Himalayas
Phytogeographically, the Eastern Himalaya forms a distinct floral region and comprises Nepal, Bhutan, neighbouring states of east and north-east India, and a contiguous sector Yunnan province in south western China. In the whole of Eastern Himalaya, there are an estimated 9000 plant species, with 3500 (i.e. 39%) of them being endemic. In India�s sector of the area, there occur some 5800 plant species, roughly 2000 (i.e. 36%) of them being endemic.
At least 55 flowering plants endemic to this area are recognised as rare, for example, the pitcher plant (Nepenthes khasiana).
The area has long been recognised as a rich centre of primitive flowering plants and the area is recognised as 'Çradle of Speciation�. Species of several families of monocotyledons, Orchidaceae, Zingiberaceae and Arecaceae abound in the area. Gymnorperms and pteridophytes (ferns) are also well represented in the area.
The area is also rich in wild relatives of plants of economic significance, e.g. rice, banana, citrus, ginger, chilli, jute and sugarcane. The region is regarded as the centre of origin and diversification of five palms of commercial importance namely, coconut, arecanut, palmyra palm, sugar palm and wild date palm.
Tea (Thea sinensis) is reported to be in cultivation in this region for the last 4000 years. Many wild and allied species of tea, the leaves of which are used as substitute of tea, are found growing in the North East in their natural habitats.
The �taxol�plant Taxus wallichiana is sparsely distributed in the region and has come under red data category due to its over exploitation for extraction of a drug effectively used against cancer.
As regards faunal diversity, 63% of the genera of land mammals in India are known form this area. During the last four decades, two new mammals have been discovered from the region : Golden Langur from Assam � Bhutan region, and Namdapha flying squirrel from Arunachal Pradesh indicating the species richness of the region.
The area is also a rich centre of avian diversity � more than 60% of the Indian birds are recorded in the North East. The region also has two endemic genera of lizards, and 35 endemic reptilian species, including two turtle. Of the 204 Indian amphibians, at least 68 species are known from North East, 20 of which are endemic.
From Namdapha National Park itself, a new genus of mammal, a new subspecies of bird, 6 new species of amphibia, four new species of fish, at least 15 new species of beetles and 6 new species of flies have been discovered.
Western Ghats
The Western Ghats region is considered as one of the most important biogeographic zones of India, as it is one of the richest centres of endemism. Due to varied topography and micro-climatic regimes, some areas within the region are considered to be active zones of speciation.
The region has 490 arborescent taxa, of which as many as 308 are endemics. This endemism of tree species shows a distinct trend, being the highest (43%) in 8N � 100 30�N location and declining to 11% in 16 N � 160 30�N location.
About 1500 endemic species of dicotyledonous plants are reported from the Western Ghats. 245 species of orchids belonging to 75 genera are found here, of which 112 species in 10 genera are endemic to the region.
As regards the fauna, as many as 315 species of vertebrates belonging to 22 genera are endemic, these include 12 species of mammals, 13 species of birds, 89 species of reptiles, 87 species of amphibians and 104 species of fish.
The extent of endemism is high in amphibians and reptiles. There occur 117 species of amphibians in the region, of which 89 species (i.e. 76%) are endemic. Of the 165 species of reptiles found in Western Ghats, 88 species are endemic.
Many of the endemics and other species are listed as threatened. Nearly 235 species of endemic flowering plants are considered endangered. Rare fauna of the region includes : Lion Tailed Macaque, Nilgiri Langur, Nilgiri Tahr, Flying Squirrel, and Malabar Gray Hornbill.
Advertisements
No comments:
Post a Comment