Biodiversity & Hotspots
The three levels of biodiversity, why it matters, the criteria for biodiversity hotspots, and India's four hotspots as a megadiverse nation.
Key Takeaways
- Biodiversity has three levels — genetic, species and ecosystem.
- A biodiversity hotspot must have high endemism and have lost most of its original habitat.
- India has four biodiversity hotspots and is one of the world's megadiverse countries.
Core concept
Biodiversity — the variety of life at all levels — is the foundation of the ecosystem services that sustain us (food, water, medicine, climate regulation). The term was popularised by E. O. Wilson. It is studied at three levels.
Static foundation — three levels of biodiversity
- Genetic diversity: variation within a species (e.g., thousands of rice varieties).
- Species diversity: the variety of species in a region.
- Ecosystem diversity: the variety of habitats and ecological processes.
Measuring Diversity
| Type | Meaning |
|---|---|
| Alpha (α) diversity | Diversity WITHIN a single community or habitat |
| Beta (β) diversity | The change in diversity BETWEEN habitats |
| Gamma (γ) diversity | Total diversity across a large landscape or region |
What makes a 'biodiversity hotspot'?
A concept by Norman Myers, a hotspot must meet two strict criteria: (1) it has at least 1,500 endemic vascular plant species (high irreplaceability), AND (2) it has lost at least 70% of its original habitat (high threat). There are 36 hotspots globally, covering a tiny area but a huge share of species. India's four: the Himalaya, the Western Ghats & Sri Lanka, Indo-Burma, and Sundaland (the Nicobar Islands).
Relevance & current linkage
India is a party to the Convention on Biological Diversity and has a Biological Diversity Act (2002) with the NBA and biodiversity boards. Global target: the Kunming-Montreal Global Biodiversity Framework aims to protect 30% of land and sea by 2030 ('30x30'). (Add a current conservation or hotspot-threat story.)
Prelims trap zones
- Both criteria (endemism AND habitat loss) are needed for a hotspot — not just species richness.
- The Western Ghats and Sri Lanka form ONE hotspot; the Himalaya is another — India has four in total.
- Endemic ≠ endangered — endemic means found nowhere else (it may still be common there).
Knowledge Check
2 questions · check your understanding
1. How many biodiversity hotspots lie (fully or partly) in India?
2. A species found in only one geographical area and nowhere else is called:
Prelims Pointers
- Hotspot criteria (Norman Myers): at least 1,500 endemic vascular plant species AND over 70% habitat loss.
- India's four hotspots: the Himalaya, the Western Ghats & Sri Lanka, Indo-Burma, and Sundaland (Nicobar Islands).
- Endemic species are found nowhere else; India is one of 17 'megadiverse' countries.
- Alpha, beta and gamma diversity measure diversity within, between and across habitats.
Mains Angle
- 'India's biodiversity is a national and global asset under threat.' Discuss.
- Why do biodiversity hotspots deserve priority in conservation?
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