Biodiversity: Hotspots, IUCN Red List and Conservation Strategies
Biodiversity for UPSC: levels and patterns, megadiversity, hotspot criteria, IUCN Red List categories, threats, in-situ and ex-situ conservation and the Biological Diversity Act.
SyllabusGS III · General issues on environmental ecology, biodiversity and climate change (Prelims); conservation (GS III)
Prerequisites: Ecosystems: Structure, Energy Flow and Nutrient Cycles · Biodiversity and Conservation — overview
The Hook: Thirty by Thirty
In December 2022, at the fifteenth Conference of the Parties (COP15) to the Convention on Biological Diversity, held in Montreal under China’s presidency, countries adopted the Kunming-Montreal Global Biodiversity Framework. It has four goals for 2050 and 23 targets for 2030. The headline target, often called “30 by 30”, asks countries to ensure that at least 30% of land, inland waters and coastal and marine areas are effectively conserved by 2030.
The question it raises: what exactly are we trying to conserve, how do we know which species are in danger, and which tools actually work?
The Core Concept
Biodiversity is the variety of life at all levels of biological organisation. The term was popularised by the American biologist Edward O. Wilson. The Convention on Biological Diversity (1992) defines it as variability among living organisms from all sources, including diversity within species, between species and of ecosystems.
Three levels of biodiversity
| Level | Meaning | Example |
|---|---|---|
| Genetic diversity | Variation in genes within a species | Thousands of traditional rice varieties in India; different strains of a medicinal plant producing different amounts of an active chemical |
| Species diversity | Variety of species in an area | The Western Ghats have more amphibian species than the Eastern Ghats |
| Ecosystem diversity | Variety of habitats and ecosystems | Deserts, rainforests, mangroves, coral reefs, alpine meadows within one country |
Ecologists also measure diversity at three spatial scales (a framework associated with R.H. Whittaker):
- Alpha diversity — within a single community or habitat.
- Beta diversity — the change in species composition between communities along a gradient.
- Gamma diversity — total diversity of a whole landscape or region.
Patterns of biodiversity
- Latitudinal gradient: diversity generally decreases from the equator towards the poles. Tropical regions have had long, relatively undisturbed evolutionary time, less seasonal and more stable climates, and more solar energy, which supports higher productivity.
- Species–area relationship: Alexander von Humboldt observed that species richness increases with area, but only up to a limit. On a log scale the relation is a straight line, log S = log C + Z log A, where Z (the slope) usually lies between 0.1 and 0.2 for smaller regions; for very large areas such as whole continents it is much steeper (about 0.6 to 1.2), as described in NCERT Biology (Class XII).
- Rivet popper hypothesis: the ecologist Paul Ehrlich compared an ecosystem to an aeroplane held together by rivets (species). Losing a few rivets may not matter at first, but each loss weakens the plane, and losing a key rivet can bring it down.
Where biodiversity is concentrated
Megadiverse countries: Conservation International identified 17 countries that together hold the majority of the world’s species. India is one of them. According to the Ministry of Environment, Forest and Climate Change (MoEFCC), India has about 2.4% of the world’s land area but accounts for roughly 7–8% of recorded species.
Biodiversity hotspots: the concept was proposed by the British ecologist Norman Myers in 1988. Conservation International’s criteria for a hotspot are:
- At least 1,500 species of vascular plants found nowhere else (endemics), and
- The region must have lost at least 70% of its original natural vegetation.
Conservation International recognises 36 hotspots worldwide. Four cover parts of India:
| Hotspot | Indian portion |
|---|---|
| Himalaya | The Indian Himalayan region |
| Indo-Burma | Much of north-east India, and the Andaman Islands |
| Western Ghats and Sri Lanka | Western Ghats |
| Sundaland | Nicobar Islands |
The Andaman Islands are generally included in the Indo-Burma hotspot, while the Nicobar Islands fall in Sundaland — a favourite Prelims distinction.
IUCN Red List: how threat is measured
The International Union for Conservation of Nature (IUCN), founded in 1948 and headquartered in Gland, Switzerland, maintains the Red List of Threatened Species, started in 1964. Species are assessed against five quantitative criteria:
| Criterion | What it measures |
|---|---|
| A | Reduction in population size |
| B | Small geographic range with fragmentation, decline or fluctuations |
| C | Small population size with decline |
| D | Very small or restricted population |
| E | Quantitative analysis of extinction probability |
graph TD
A[Evaluated species] --> B[Adequate data]
A --> C[Data Deficient - DD]
B --> D[Extinct - EX]
B --> E[Extinct in the Wild - EW]
B --> F[Threatened]
F --> G[Critically Endangered - CR]
F --> H[Endangered - EN]
F --> I[Vulnerable - VU]
B --> J[Near Threatened - NT]
B --> K[Least Concern - LC]
L[Not Evaluated - NE]Only CR, EN and VU count as “threatened”. Under criterion E, for example, a species qualifies as Critically Endangered if its probability of extinction in the wild is at least 50% within 10 years or three generations; Endangered at least 20% within 20 years or five generations; Vulnerable at least 10% within 100 years.
Threats to biodiversity
NCERT calls the four main causes the “Evil Quartet”:
- Habitat loss and fragmentation — the most important cause; fragmentation hurts animals needing large territories and migratory species.
- Over-exploitation — Steller’s sea cow and the passenger pigeon were driven to extinction by human over-use.
- Alien species invasions — the Nile perch introduced into Lake Victoria in East Africa is linked to the extinction of many native cichlid fish; Parthenium (carrot grass), Lantana and water hyacinth (Eichhornia) are invasive in India, and the illegally introduced African catfish (Clarias gariepinus) threatens native catfishes.
- Co-extinctions — when a species becomes extinct, plants and animals obligately associated with it also die out (a host fish and its parasites; a plant and its pollinator).
Pollution and climate change are increasingly added to this list. The IPBES Global Assessment (May 2019) estimated that around one million animal and plant species are threatened with extinction.
Examples of recent extinctions cited in NCERT include the dodo (Mauritius), the quagga (Africa), the thylacine (Australia), Steller’s sea cow (Russia), and three subspecies of tiger (Bali, Javan and Caspian). In India, the cheetah was declared extinct in 1952.
Conservation: in-situ and ex-situ
| Approach | Meaning | Examples |
|---|---|---|
| In-situ (“on site”) | Protect species in their natural habitat, along with the processes that sustain them | National parks, wildlife sanctuaries, biosphere reserves, tiger reserves, community reserves, sacred groves, Ramsar sites |
| Ex-situ (“off site”) | Protect species outside their natural habitat | Zoos, botanical gardens, wildlife safari parks, seed banks, gene banks, cryopreservation, tissue culture |
- Sacred groves are forest patches protected by communities on religious grounds — for example in the Khasi and Jaintia Hills (Meghalaya), the Western Ghats of Karnataka and Maharashtra, the Aravalli hills of Rajasthan, and parts of Chhattisgarh.
- Cryopreservation stores gametes, embryos or seeds at about −196 °C in liquid nitrogen.
- The National Bureau of Plant Genetic Resources (NBPGR), New Delhi, houses India’s national gene bank for plant genetic resources.
- The Svalbard Global Seed Vault in Norway, opened in 2008, stores duplicate seed samples from gene banks worldwide as a back-up.
The Biological Diversity Act, 2002
Enacted to give effect to India’s obligations under the Convention on Biological Diversity, the Act regulates access to biological resources and associated traditional knowledge and requires fair and equitable sharing of benefits. It was amended by the Biological Diversity (Amendment) Act, 2023, which, among other changes, eased compliance for Indian users including the AYUSH sector and replaced several criminal penalties with monetary ones.
| Tier | Body | Role |
|---|---|---|
| National | National Biodiversity Authority (NBA), Chennai, set up in 2003 | Approvals for access by foreign entities, for transfer of research results abroad, and for intellectual property rights based on Indian biological resources |
| State | State Biodiversity Boards (SBBs) | Regulate access by Indian entities for commercial use |
| Local | Biodiversity Management Committees (BMCs) under local bodies | Prepare People’s Biodiversity Registers (PBRs) documenting local resources and knowledge |
The Act also lets State Governments, in consultation with local bodies, notify Biodiversity Heritage Sites. The first was the Nallur Tamarind Grove near Bengaluru, Karnataka (2007).
Memory Anchors
E.O. Wilson’s threats mnemonic — HIPPO: Habitat loss · Invasive species · Pollution · Population (human) · Over-harvesting
India’s four hotspots — “Him In Western Sun”: Himalaya · Indo-Burma · Western Ghats–Sri Lanka · Sundaland (Nicobar)
Threatened = “CEV”: Critically Endangered, Endangered, Vulnerable. Near Threatened is not threatened.
Comparison table
| In-situ | Ex-situ | |
|---|---|---|
| Where | Natural habitat | Outside natural habitat |
| Protects | Species plus evolutionary and ecological processes | Mainly genetic material and individuals |
| Best for | Whole ecosystems, large populations | Critically small populations, crop genetic resources |
| Example | Tiger reserve | Seed bank |
One-line Mains hook: Every lost species is a rivet popped from the aeroplane we all fly in — Paul Ehrlich’s rivet popper hypothesis in one line.
For Prelims
- Hotspot concept: Norman Myers, 1988. Criteria: ≥1,500 endemic vascular plants and ≥70% habitat loss. 36 hotspots (Conservation International); 4 cover parts of India.
- Nicobar Islands belong to the Sundaland hotspot; the Andamans to Indo-Burma.
- IUCN: founded 1948; headquarters Gland, Switzerland; Red List since 1964. Threatened = CR, EN, VU only.
- India: about 2.4% of the world’s land area, roughly 7–8% of recorded species (MoEFCC); one of the 17 megadiverse countries.
- NBA: set up 2003, headquartered in Chennai. BMCs prepare People’s Biodiversity Registers.
- Cryopreservation uses liquid nitrogen at about −196 °C.
- Species–area slope Z: about 0.1–0.2 for small regions; about 0.6–1.2 for whole continents (NCERT).
For Mains
- Dimensions: ecological (ecosystem services, resilience), economic (bio-resources, bio-economy, genetic resources for agriculture and medicine), social (community rights, traditional knowledge), legal (access and benefit sharing), ethical (intrinsic value of species).
- Keywords: endemism, habitat fragmentation, co-extinction, ecosystem services, access and benefit sharing (ABS), biopiracy, People’s Biodiversity Registers, 30 by 30, other effective area-based conservation measures (OECMs).
- Value-addition: IPBES Global Assessment (2019) on one million species threatened; the Kunming-Montreal framework (2022); sacred groves as community conservation; NBA’s role in guarding against biopiracy.
Common Traps
In the News
- December 2022 — Kunming-Montreal Global Biodiversity Framework adopted at CBD COP15, Montreal.
- August 2023 — Biological Diversity (Amendment) Act, 2023 enacted.
- See current affairs for species and Red List updates.
Practice
Prelims
Which of the following are categories of “threatened” species in the IUCN Red List?
- Critically Endangered
- Near Threatened
- Endangered
- Vulnerable
Select the correct answer using the code given below.
Solution
The IUCN Red List groups Critically Endangered, Endangered and Vulnerable as “threatened”. Near Threatened is a separate category for species close to qualifying for a threatened category — despite the word “threatened” in its name, it is not one of them.
Answer: C
Consider the following statements regarding biodiversity hotspots:
- To qualify as a hotspot, a region must have lost at least 70% of its original natural vegetation.
- A region qualifies as a hotspot if it has the highest total number of species in its continent, irrespective of endemism.
Which of the statements given above is/are correct?
Solution
Statement 1 is correct — the threat criterion is the loss of at least 70% of original habitat. Statement 2 is incorrect — the biological criterion is endemism: at least 1,500 species of vascular plants found nowhere else. Total species count alone is not a criterion.
Answer: A
The Nicobar Islands of India form part of which biodiversity hotspot?
Solution
The Nicobar Islands are part of the Sundaland hotspot, which also covers the islands of western Indonesia and peninsular Malaysia. The Andaman Islands are usually placed in Indo-Burma. The trap is to treat the two island groups as one.
Answer: B
Mains
Habitat loss, rather than hunting, is now the leading cause of biodiversity loss in India. Discuss, and suggest measures to reconcile development with conservation.
Solution
Introduction: India is one of the 17 megadiverse countries and has parts of four global hotspots, but its biodiversity faces pressure from a large population and rapid infrastructure growth. Habitat loss and fragmentation are the most important of NCERT’s “Evil Quartet” of threats.
Body:
- Why habitat loss dominates:
- Diversion of forest and grassland for mining, roads, dams and urban expansion.
- Fragmentation: linear infrastructure cuts corridors, isolating populations and causing road kills.
- Degradation of wetlands, grasslands (often classified as “wastelands”) and coastal ecosystems.
- Invasive species such as Lantana and Prosopis juliflora degrade remaining habitat.
- Why hunting has relatively declined: strong legal protection under the Wildlife (Protection) Act, enforcement agencies, CITES-linked trade controls — though poaching for illegal trade persists.
- Measures:
- Landscape-level planning; wildlife corridors and mitigation structures on highways and railways.
- Rigorous and transparent environmental impact assessment and cumulative assessment.
- Restoration of grasslands and wetlands; removal of invasive species.
- Community-based conservation: BMCs, People’s Biodiversity Registers, sacred groves, community reserves.
- Recognising other effective area-based conservation measures towards the “30 by 30” target.
Conclusion: Development and conservation can be reconciled if biodiversity is treated as infrastructure — planned, mapped and protected at the landscape scale rather than traded off project by project.
Quick Revision
| Point | One-liner |
|---|---|
| Levels | Genetic, species, ecosystem |
| Scales | Alpha (within), beta (between), gamma (regional) |
| Hotspot | Myers 1988; ≥1,500 endemic plants + ≥70% habitat lost |
| India’s hotspots | Himalaya, Indo-Burma, Western Ghats–Sri Lanka, Sundaland (Nicobar) |
| IUCN | 1948; Gland; Red List 1964 |
| Threatened | CR, EN, VU |
| Evil Quartet | Habitat loss, over-exploitation, alien invasions, co-extinction |
| Cheetah extinct in India | 1952 |
| NBA | 2003, Chennai; BMCs keep PBRs |
| GBF | Kunming-Montreal, December 2022; 30 by 30 |
Key Takeaways
- Hotspots are defined by endemism plus threat, not by species count alone.
- Only CR, EN and VU are “threatened” in the IUCN Red List.
- In-situ conservation protects processes as well as species; ex-situ is a back-up, not a substitute.
- The Biological Diversity Act’s three tiers — NBA, SBBs, BMCs — put access and benefit sharing into Indian law.
Related Topics
- Biodiversity and Conservation — quick revision
- Biodiversity and Conservation — practice questions
- Protected Areas and Wildlife
- International Environmental Conventions
- Natural Vegetation and Wildlife