Biodiversity hotspots

The British biologist Norman Myers coined the term ‘ biodiversity hotspot’ in 1998  as a biogeography region characterized both by exceptional levels of plant endemism  and by serious levels of habitat loss. Endemism means a species is found in a particular are only it is confined to that area and not found outside. According to Conservation  international (CI) , to qualify as a hotspot a region  must meet two criteria: it must contain at least 1500 species of vascular plants (more than 0.5% of the word’s total) as endemics, and it has to have lost at least 70% of its original habitat. At present there are total 34 biodiversity hotspots in the world, of which 3 are in India:

(1)    Western Ghats

(2)    North-east India; and

(3)    Himalayas

Collectively these areas held as endemics include about 44% of the world’s plants and 35% of terrestrial vertebrates. The habitat extant of this area has been reduced by 88% of its original extant, such that this earth of biodiversity is now restricted to only around 2% of earth’s land surface. Thus, identification of biodiversity hotspots gives us the address of places where there is a need to start the measures for protection and conservation of biodiversity. The common regions of biodiversity hotspots are mentioned in the next topic ‘gene pool’.

India’s Biodiversity Hotspots

(1)    The Himalayas:   Himalayan biodiversity hotspot region stretches over 3000km in northern Pakistan, India, Nepal, Bhutan, Tibet and Yunnan province of China. It includes many of the world’s tallest peaks along with Mt. Everest as well as many of the world’s deepest river gorges. This mountain range has been divided into two regions: The Eastern Himalayas and the Western Himalayas with the division occurring approximately in eastern Nepal. The abrupt rise of Himalayan mountains from less than 500 m to more than 8000 m results in diversity of ecosystems that range, in only a couple of hundred kilometers, form alluvial grasslands (in Assam-among the tallest in world) and subtropical forests along the foothills to broad leaf forests in mid hills, conifer and forests in the higher hills and alpine meadows above the tree line. Numerous large birds and mammals including vultures, tigers, leopards, elephants, rhinos, and wild water buffalo are found in Himalayas. The area has 3160 endemic species in the available hotspot vegetation region of around 1, 85,427 km².

(2)    Eastern Himalayas: This region which was earlier part of Himalayas has been recently made part of broader indo-Burma hotspot region by the Conservation international (CI). The WWF has identified the entire Eastern Himalayas as a priority in the list of Global 200 Ecoregions. It includes north-east India from Sikkim, Bhutan, northern Myanmar and southern part of Yunnan of China. at the confluence of indo –Malayan, indo-Chinese and Indian biogeographically realms, the region supports 51 forest types, 836 of the 1200 bird species of Indian subcontinent, 6 out of 9 important vegetation types of India, 800 out of 1500 species of flowering plants (and approximately 1235 rich and diverse tribal cultures which have an important role for conservation of biodiversity in the region). The region has also been recognized as Endemic Bird Area. As per IUCN, the region also has exceptional fresh water diversity.

(3)    Western Ghats and Sri Lanka: This region is characterized by very high endemicity (52%) i.e. around 3000 vascular plant species are endemic to the region. The highest concentration of species is believed to be around Agasthyamalai hills. The region also harbours over 450 bird species, 140 mammalian species, 260 reptiles and 175 amphibians. Over 60% of amphibians and reptiles are endemic to the region. This area is under tremendous pressure of rapid loss of biodiversity and habitat due to deforestation, urbanization and development projects. Today only 44000 km² out of the original 1, 80,000 km² and 1.5% of Sri Lanka’s original forest cover are remaining. Recently UUESCO granted the recognition of World Heritage site to Western Ghats Ecological Region due to its biodiversity.

Gene Pool

Gene pool refers to the total stock of genes found in an interbreeding population. Gene Pool centre refer to areas on the earth which are seen as places where important crop plants and domestic animals originated. These regions have extraordinary range of biodiversity. These are also called global regions of biodiversity. Some such areas are:

(1)    Southeast Asia

(2)    East Asia (China, Japan)

(3)    South Asia (Indian, indo-Chinese,  Indo – Burman)

(4)    Central Asia

(5)    Asia Minor and Mediterranean

(6)    Ethiopia

(7)    Andes

(8)    Mexico and Central America

The importance of gene pools is same as that of biodiversity regions.