Biodiversity & conservation
Biodiversity types, India's biogeographic wealth, in-situ and ex-situ conservation, and the legal-institutional architecture protecting it, tuned for UPSC Prelims and Mains GS-3.
What biodiversity means
Biodiversity, a term popularised by entomologist E.O. Wilson in 1986, denotes the variability among living organisms across three nested levels. Genetic diversity is the variation of genes within a species — the basis of breeds of cattle, the 50,000-plus rice landraces once grown in India, and the resilience that lets populations adapt. Species diversity is the variety of species in a region, measured through richness (count) and evenness (relative abundance). Ecosystem diversity captures the variety of habitats, biotic communities and ecological processes — from the Sundarbans mangroves to the cold desert of Ladakh.
Ecologists distinguish alpha diversity (within a single community), beta diversity (turnover of species between communities along a gradient), and gamma diversity (total diversity across a landscape). The Shannon and Simpson indices quantify alpha diversity.
India's biogeographic wealth
India holds about 2.4% of the world's land area but roughly 7-8% of recorded species, making it one of 17 megadiverse countries identified by Conservation International (1998). The Wildlife Institute of India recognises 10 biogeographic zones (Trans-Himalaya, Himalaya, Desert, Semi-Arid, Western Ghats, Deccan Peninsula, Gangetic Plain, North-East, Islands, Coasts).
India contains parts of four of the world's 36 biodiversity hotspots defined by Norman Myers (1988, revised 2000): the Himalaya, the Indo-Burma region, the Western Ghats–Sri Lanka, and the Sundaland (Nicobar Islands). A hotspot must have at least 1,500 endemic vascular plant species and have lost 70% or more of its primary vegetation — meaning hotspots are simultaneously the richest and the most threatened areas.
Endemism and threat categories
Endemic species occur nowhere else: the lion-tailed macaque and Nilgiri tahr of the Western Ghats, the sangai (brow-antlered deer) of Loktak Lake, Manipur. The IUCN Red List classifies taxa as Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened and Least Concern. India's critically endangered species include the Great Indian Bustard, the gharial, the Kashmir stag (hangul) and the pygmy hog.
The principal drivers of biodiversity loss are summarised by the acronym HIPPO (Habitat loss, Invasive species, Pollution, human Population, Overexploitation). Habitat fragmentation is the foremost cause in India; invasive species such as Lantana camara, Prosopis juliflora and the African catfish illustrate the second. The IPBES Global Assessment (2019) warned that around one million species face extinction globally — a high-yield fact for essay and GS-3 answers.
