The most biodiversity rich area in India is

Question

UnlockIAS · Accepted Answer

Correct — C, Western Ghats. The Ghats, called the Sahyadri in the north, run about 1,600 km down India's west coast through Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu, rising to Anamudi (2,695 m) in Kerala, the highest point in India south of the Himalaya. They form a wall across the path of the south-west monsoon, wringing very heavy rainfall out of it on the windward side and creating tropical evergreen rainforest that has persisted, in fragments, for tens of millions of years. That combination of high rainfall, steep altitudinal gradients and long isolation has produced endemism found nowhere else in the country: documented counts run to about 7,402 species of flowering plants of which roughly 1,273 are endemic, and — most strikingly — about 121 amphibian species of which some 94 occur only here. Endemic mammals include the lion-tailed macaque, the Nilgiri tahr and the Nilgiri langur. This is why the Western Ghats, together with Sri Lanka, are recognised as one of the world's biodiversity hotspots, meeting Norman Myers's twin test of at least 1,500 endemic vascular plant species and the loss of at least 70 per cent of original primary vegetation; and why, in 2012, 39 serial sites of the Ghats in seven clusters were inscribed on the UNESCO World Heritage List. No other option in this question is a global hotspot at all.

Why the other options are wrong — (a) India's most fertile and most densely populated region — and that is exactly the problem. Millennia of intensive cultivation, irrigation and settlement have converted the alluvial plain into an almost wholly human-modified landscape with very little natural forest left and negligible endemism. Agricultural productivity and biological diversity are different things, and this option trades on confusing them.  (b) The cold desert north of the Great Himalayan range — Ladakh, the Spiti and Lahaul valleys, northern Sikkim. It holds superbly adapted specialist fauna such as the snow leopard, the kiang, the Tibetan antelope and the black-necked crane, but extreme cold, thin air and rainfall of only a few hundred millimetres a year keep total species richness low. Note the deliberate near-miss: the EASTERN Himalaya belongs to the Himalaya biodiversity hotspot, but the Trans-Himalaya does not.  (d) The Satpura-Maikal and Deccan belt carries India's great tiger landscapes — Kanha, Pench, Bandhavgarh, Satpura — and extensive teak and sal forest, so it is genuinely rich in large mammals. But its vegetation is tropical dry and moist DECIDUOUS forest, which supports far fewer species and far less endemism than evergreen rainforest, and no part of it qualifies as a global biodiversity hotspot. Charismatic megafauna is not the same as biodiversity.

Concept: A biodiversity hotspot, as defined by Norman Myers in 1988 and revised in 2000, is a region that satisfies two conditions simultaneously: it contains at least 1,500 species of endemic vascular plants — more than half a per cent of the world's total — and it has already lost at least 70 per cent of its original primary vegetation. Endemism plus threat, in other words, not raw species count. Thirty-six such zones are recognised worldwide, and they occupy a small fraction of the land surface while holding a disproportionate share of the planet's species. Four of them extend into India: the Himalaya, Indo-Burma, the Western Ghats and Sri Lanka, and the Nicobar Islands as part of Sundaland.

State PCS 2019 Q104 — Environment & Ecology PYQ with Answer

State PCS 2019 Q104 — Environment & Ecology PYQ with Answer