What are ‘biodiversity hotspots’ known for?

The correct answer is Option (2) → High levels of species richness and endemism

No country has enough money to protect every species. So conservationists picked out certain regions for maximum protection, called biodiversity hotspots. Two features decide a hotspot: very high species richness (a large number of species) and a high degree of endemism. Endemic species are found only in that region and nowhere else. There are 34 hotspots in the world. Three of them cover India: the Western Ghats and Sri Lanka, Indo-Burma and the Himalaya.

Option (1) High levels of pollution — Incorrect. Pollution damages habitats. Hotspots are chosen for their rich wildlife, not for pollution.

Option (2) High levels of species richness and endemism — Correct. Hotspots have very many species, and many of them are found nowhere else.

Option (3) Intensive agricultural activities — Incorrect. Farming clears natural habitats. Hotspots are in fact regions of fast habitat loss, which is why they need protection.

Option (4) Low population density — Incorrect. Hotspots are defined by their species, not by the number of people living there.

NCERT Extract:
How Do We Conserve Biodiversity? – “… On a global basis, this problem has been addressed by eminent conservationists. They identified for maximum protection certain ‘biodiversity hotspots’ regions with very high levels of species richness and high degree of endemism (that is, species confined to that region and not found anywhere else). Initially 25 biodiversity hotspots were identified but subsequently nine more have been added to the list, bringing the total number of biodiversity hotspots in the world to 34. These hotspots are also regions of accelerated habitat loss.”