In India, which of the following has become a hot-spot with reference to threats to biodiversity ?

Question

UnlockIAS · Accepted Answer

Correct — option (3). A biodiversity hot-spot is not simply a region with a great many species; it is a region that is exceptionally rich in species found nowhere else and is at the same time under severe threat, and the two conditions have to be met together. The criteria used since Norman Myers proposed the idea, and applied by Conservation International, are that the region must hold at least fifteen hundred species of endemic vascular plants and must have lost at least seventy per cent of its original primary vegetation. Four such regions extend into India — the Himalaya, Indo-Burma, the Western Ghats with Sri Lanka, and Sundaland, which reaches India in the Nicobar Islands — and of the four regions named in the options, north-eastern India is the one that answers to the description. It does so twice over, because the north-east lies within the Indo-Burma hot-spot and its northern hills fall within the Himalaya hot-spot as well. The reason for that richness is its position: the north-east is where the Indian, the Indo-Malayan and the Indo-Chinese biological regions meet, so plants and animals from three great assemblages occur together, and the sharp gradients of altitude and rainfall between the Brahmaputra valley and the eastern Himalaya multiply the habitats available in a small area. The region is also under pressure that fits the second half of the definition — forest clearance, shifting cultivation on shortened cycles, mining, road and dam building and the wildlife trade — which is precisely why it is classed as a hot-spot rather than merely as a rich region. Option (3) is the answer.

Why the other options are wrong — (a) North-western India is not a biodiversity hot-spot and is not a candidate for one. The region is dominated by the Thar desert and the arid and semi-arid tracts of Rajasthan, Punjab and Haryana, and while its ecology is of great interest — the Great Indian Bustard, the blackbuck and the desert fox belong to it, and the Rann of Kachchh is the last home of the Indian wild ass — arid regions are by their nature poor in the number of endemic plant species that the hot-spot criterion requires. The distinction the question is testing is between a region that is ecologically important and a region that qualifies as a hot-spot, and they are not the same thing. Aridity limits both the total number of species and the concentration of endemics, so however valuable the desert ecosystems may be, they do not meet the test.  (b) The Deccan plateau is not recognised as a biodiversity hot-spot, and the option is offered because it lies next door to one. The plateau is a vast, ancient and relatively dry surface carrying deciduous forest, scrub and cultivated land, and while it holds important protected areas, its flora and fauna are widespread rather than narrowly endemic. The hot-spot on this side of the country is the chain of the Western Ghats, which forms the plateau's western edge and is a different thing from the plateau itself: the Ghats intercept the monsoon, carry evergreen and semi-evergreen forest, and have a level of endemism among plants, amphibians and fish that the plateau in their rain shadow does not approach. Confusing a hot-spot with the larger region beside it is the standard error in this family of questions.  (d) Western India is the most tempting of the wrong options, because the Western Ghats are a recognised hot-spot and they do run along the western side of the peninsula. But the hot-spot is the Ghats themselves, a narrow chain of hills extending from the Tapi valley south through Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu and continuing into Sri Lanka, and it is not the same as the broad region ordinarily called western India, most of which — the Gujarat plains, the Kachchh and Saurashtra peninsulas, the Rajasthan borderlands — lies outside it. The option asks the candidate to accept a macro-region in place of the specific mountain chain that qualifies. When an option names a large region and the hot-spot within it is a much smaller and well-defined chain, the option is not a correct statement of where the hot-spot is.

Concept: The hot-spot concept was introduced to solve a practical problem in conservation: funds and effort are limited, so where should they be concentrated to save the greatest number of species from extinction ? The answer proposed was to identify regions that combine two properties — an exceptional concentration of endemic species, which means species that occur nowhere else and would be lost outright if the region were destroyed, and an exceptional degree of threat, measured by how much of the original vegetation has already gone. A region qualifies if it holds at least fifteen hundred endemic species of vascular plants and has lost at least seventy per cent of its primary vegetation, and about three dozen such regions are recognised across the world. Four of them reach India. The Himalaya hot-spot covers the mountain arc, including the eastern Himalaya of Sikkim and Arunachal Pradesh; the Indo-Burma hot-spot covers the north-eastern states beyond the Himalaya and extends into Myanmar and mainland South-East Asia; the Western Ghats and Sri Lanka form a hot-spot along the western edge of the peninsula; and Sundaland reaches Indian territory in the Nicobar Islands. India is separately counted among the world's seventeen megadiverse countries, a related but distinct designation that rests on the sheer number of species a country holds rather than on the combination of endemism and threat.

State PCS 2022 Q16 — Environment & Ecology PYQ with Answer

State PCS 2022 Q16 — Environment & Ecology PYQ with Answer