Three of the following criteria have contributed to the recognition of western Ghats-Sri Lanka and Indo-Burma regions as hotspots of biodiversity: 1) Species richness 2) Vegetation density 3) Endemism. 4) Ethno-botanical importance 5) Threat perception 6) Adaptation of flora and fauna to warm arid humid conditions Which three of the above are correct criteria in this context?

Norman Myers, who first proposed the hotspot idea in 1988, set two tests. A hotspot must hold a large number of endemic plant species, found nowhere else, and must have lost at least 70 per cent of its original habitat. That second test is the threat perception criterion. Species richness is the third pillar of the argument, since these regions hold very high numbers of species. So 1, 3 and 5 are correct, and option C is right.

• 2 (vegetation density) is wrong. Hotspots are judged by how much habitat is left and how unique its species are, not by how thick the canopy is.
• 4 (ethno-botanical importance) is wrong. Human use of plants matters for conservation policy, but it is not part of the hotspot criteria.
• 6 (adaptation to warm arid conditions) is wrong on two counts. The Western Ghats and Indo-Burma are humid, not arid, and adaptation to climate is not a hotspot criterion.

This links to GS-III on conservation and the Biological Diversity Act, 2002, which created the National Biodiversity Authority. Myers' criteria are still the standard reference, though later updates to the global hotspot list have changed the number of hotspots.

Trap: Candidates often pick option B because dense forest and ethno-botany sound like biodiversity, or they treat "adaptation to climate" as a general ecological criterion. Stick to endemism, richness and threat.