Question
Define biodiversity hotspots. What are the criteria used to designate an area as a hotspot? Name the two biodiversity hotspots located in India and describe their significance.
Solution — Step by Step
A biodiversity hotspot is a region that is exceptionally rich in species (particularly endemic species) but is also under severe threat from human activities. The term was coined by ecologist Norman Myers in 1988.
The core idea: these are the places where biodiversity loss would be most catastrophic — areas where we get the most “biodiversity per square kilometre” and where that biodiversity is most endangered.
To qualify as a biodiversity hotspot, a region must satisfy both of the following:
-
High endemism: Must contain at least 1,500 species of vascular plants as endemics (plants found nowhere else on Earth). Endemism, not just species richness, is the key — it measures irreplaceability.
-
High threat level: Must have lost at least 70% of its original habitat (meaning only 30% or less of primary vegetation remains).
Currently, 36 biodiversity hotspots have been identified worldwide, covering only ~2.5% of Earth’s land surface but harbouring over 50% of the world’s endemic plant species and ~43% of endemic vertebrate species.
India has two recognised biodiversity hotspots:
1. The Western Ghats (+ Sri Lanka): Runs along India’s west coast for about 1,600 km. Contains extraordinary endemism — over 5,000 endemic species of flowering plants, fish, amphibians, reptiles, birds, and mammals. The lion-tailed macaque, Malabar giant squirrel, and Nilgiri tahr are iconic endemic animals. Only about 6.8% of original habitat remains.
2. The Himalayas (Eastern Himalayas / Indo-Burma region): The eastern Himalayas and adjoining areas are part of the Indo-Burma hotspot. Rich in rhododendrons, orchids, and a staggering diversity of plants adapted to altitudinal gradients. Species include the snow leopard, red panda, and various endemic amphibians.
Hotspots guide conservation priorities — limited resources should be directed where they will protect the most irreplaceable biodiversity. The “conservation bang per buck” is highest in hotspots.
Protected areas, wildlife sanctuaries, and biosphere reserves within hotspots receive priority for funding, research, and anti-poaching efforts. In India, the Western Ghats hotspot overlaps significantly with protected areas like Silent Valley National Park, Agastyamalai Biosphere Reserve, and Nilgiri Biosphere Reserve.
Why This Works
The hotspot concept is essentially a triage framework — not all areas can be equally protected, so we identify where protection is most urgent (high threat) and most impactful (high irreplaceable species). The combination of endemism + threat ensures hotspots are both unique and in danger — satisfying both biodiversity and conservation urgency criteria simultaneously.
This is different from simply protecting the most species-rich areas (some species-rich areas have wide geographic ranges, so their species can survive elsewhere).
Alternative Method — In-situ vs Ex-situ Context
Hotspot conservation is an example of in-situ conservation — protecting species in their natural habitat. This is contrasted with ex-situ conservation (zoos, seed banks, botanical gardens) where species are maintained outside their natural habitat. In-situ conservation in hotspots is the first priority because it preserves not just species but entire ecosystems and ecological processes.
Common Mistake
Students often list “high number of species” as the only criterion, missing the crucial point that endemism (uniqueness, irreplaceability) and habitat loss (threat level) are the two official criteria. A rainforest can have enormous species richness but if those species are widely distributed and habitat is intact, it may not qualify as a hotspot.
Also, many students name only the Western Ghats as India’s hotspot. Remember, India has two: Western Ghats (+ Sri Lanka) and Eastern Himalayas (part of the Indo-Burma hotspot).
NEET regularly asks: (1) who coined the term — Norman Myers; (2) criteria — ≥1,500 endemic vascular plants + ≥70% habitat lost; (3) India’s hotspots — Western Ghats and Eastern Himalayas; (4) total number of hotspots worldwide — 36 (this number updates, so check current NCERT). These four facts cover most hotspot questions.