Which one of the following is not a cause of loss of biodiversity?

The correct answer is Option (1) → Afforestation

NCERT names four major causes of biodiversity loss, called ‘The Evil Quartet’: habitat loss and fragmentation, over-exploitation, alien species invasions and co-extinctions.

Option (1) Afforestation — Not a cause of biodiversity loss. Afforestation means planting trees on land. It builds habitats back, the opposite of habitat loss.

Option (2) Habitat loss — A cause of biodiversity loss. It is the most important cause; tropical rain forests have shrunk from more than 14 per cent of the earth’s land to no more than 6 per cent.

Option (3) Alien species invasions — A cause of biodiversity loss. Species brought in from outside may turn invasive, like the Nile perch that wiped out over 200 cichlid fish species in Lake Victoria.

Option (4) Co-extinction — A cause of biodiversity loss. When a species dies out, species tied to it in an obligatory way die out too, such as a host fish and its parasites.

Note: A similar question was also asked in CUET (UG) 2025 on 20-05-2025 (Slot 2).