Biodiversity: Levels, Hotspots, Threats and the IUCN Red List
Biodiversity for CGPSC: genetic, species and ecosystem diversity, megadiverse India, 10 biogeographic zones, 36 hotspots, threats and IUCN categories.
Prerequisites
- Ecosystems — ecosystem diversity is one of the three levels of biodiversity.
- Forest Types of India — vegetation zones underlie India’s biogeographic zones.
The Hook: The Last Wild Buffaloes of Udanti
Chhattisgarh’s state animal, the wild water buffalo (वन भैंसा), survives in very small numbers in the Udanti–Sitanadi and Indravati areas. Its domestic cousin grazes in every village of the plains, so why does the wild one matter?
Because it carries genes that domestic buffaloes have lost, it plays a role in grassland ecosystems that nothing else fills, and once it is gone it cannot be recreated. What exactly is biodiversity, how is it measured, where is it concentrated, and why is it disappearing?
Why it matters: Prelims tests numbers and lists (36 hotspots, India’s four, 17 megadiverse countries, 10 biogeographic zones, IUCN categories). Mains GS-II asks about the value of biodiversity and threats to it, where a Chhattisgarh example lifts the answer.
What Is Biodiversity (जैव विविधता)?
The Convention on Biological Diversity (1992), Article 2, defines biological diversity as the variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes they are part of. It includes diversity within species, between species and of ecosystems. The word “biodiversity” was popularised by the biologist E.O. Wilson in the late 1980s.
Three levels
| Level | Meaning | Example |
|---|---|---|
| Genetic diversity (आनुवंशिक विविधता) | Variation in genes within a species | Thousands of traditional rice varieties of Chhattisgarh (the “rice bowl”); wild vs domestic buffalo |
| Species diversity (प्रजातीय विविधता) | Variety and number of species in an area | Plants and animals of Kanger Valley National Park |
| Ecosystem diversity (पारितंत्र विविधता) | Variety of habitats and ecosystems | Sal forests, grasslands, rivers and reservoirs within one state |
Measuring diversity (Whittaker)
| Measure | What it compares |
|---|---|
| Alpha (α) diversity | Species diversity within one community or habitat |
| Beta (β) diversity | Change in species between communities along a gradient (e.g., from the plains up the Maikal hills) |
| Gamma (γ) diversity | Overall diversity of a large region containing many habitats |
Patterns of distribution
- Latitudinal gradient: Diversity generally increases from the poles towards the equator. Tropical regions have stable climates, long evolutionary history and high productivity.
- Species–area relationship (Alexander von Humboldt): Within a region, species richness rises with the area explored, but at a decreasing rate.
- Endemic species (स्थानिक प्रजाति): Found naturally only in one region. Islands and isolated mountains (Western Ghats, North-East) have high endemism.
India: A Megadiverse Country
- India has about 2.4% of the world’s land area but about 7–8% of recorded species.
- India is one of the 17 megadiverse countries (the group identified by Conservation International and UNEP-WCMC). Others include Brazil, Indonesia, China, Mexico and Australia.
- India is also a centre of origin of crops: rice, sugarcane, many pulses, mango, citrus and spices are associated with the Indian region (Vavilov’s Hindustan centre).
Ten biogeographic zones of India
The Wildlife Institute of India (Rodgers, Panwar and Mathur) classifies India into 10 biogeographic zones:
| # | Zone | Note |
|---|---|---|
| 1 | Trans-Himalaya | Cold desert: Ladakh, Lahaul–Spiti |
| 2 | Himalaya | |
| 3 | Desert | Thar |
| 4 | Semi-arid | Punjab to Gujarat, central India’s dry west |
| 5 | Western Ghats | Very high endemism |
| 6 | Deccan Peninsula | Largest zone; includes most of Chhattisgarh |
| 7 | Gangetic Plain | |
| 8 | North-East | |
| 9 | Islands | Andaman–Nicobar, Lakshadweep |
| 10 | Coasts |
Biodiversity Hotspots (जैव विविधता हॉटस्पॉट)
The concept was proposed by Norman Myers (1988) and adopted by Conservation International. A region qualifies if it meets both criteria:
- It has at least 1,500 species of endemic vascular plants (more than 0.5% of the world total), and
- It has lost at least 70% of its original natural vegetation.
So a hotspot is rich and threatened at once. There are 36 hotspots worldwide. Together they cover only about 2.5% of Earth’s land surface but hold more than half of the world’s plant species as endemics.
- Himalaya (Indian Himalayan region with Nepal, Bhutan and others)
- Indo-Burma (North-East India, Myanmar, Thailand, Indochina)
- Western Ghats and Sri Lanka
- Sundaland (India’s share: the Nicobar Islands; the rest is Malaysia and Indonesia)
Chhattisgarh is not in any hotspot. Central Indian forests are biologically rich, but they do not meet the endemism criterion.
Values of Biodiversity
| Value | Examples |
|---|---|
| Consumptive use | Food, fuelwood, fodder, medicine used directly by local people (mahua, tendu, chironji, honey) |
| Productive use | Commercially traded products: timber, lac, pharmaceuticals, genes for crop breeding |
| Ecological / indirect | Pollination, soil fertility, watershed protection, pest control, carbon storage |
| Option value | Unknown future uses: a wild relative might hold a gene for drought tolerance |
| Aesthetic, cultural, ethical | Sacred groves, totemic species of tribal clans, tourism, the intrinsic right of species to exist |
Threats: “HIPPO”
The causes of biodiversity loss are often summarised by E.O. Wilson’s acronym HIPPO:
| Letter | Threat | Chhattisgarh / India example |
|---|---|---|
| H | Habitat loss and fragmentation (the biggest driver) | Mining, roads and reservoirs cutting forest corridors; elephants moving into villages in the north of the state |
| I | Invasive alien species | Lantana camara spreading through central Indian forests; water hyacinth in wetlands |
| P | Pollution | Fly ash and mine runoff in rivers; pesticides (vulture decline from the veterinary drug diclofenac) |
| P | Population growth of humans and consumption | Pressure on forests for fuelwood, grazing and land |
| O | Over-harvesting | Poaching of pangolins and tigers; unsustainable collection of medicinal plants |
Climate change is now added as a sixth major driver, shifting species ranges and stressing reefs and alpine species. See Climate Change.
Co-extinction: when a species goes extinct, species that depend on it obligately (a host-specific parasite, or a plant and its only pollinator) may also go extinct.
Many scientists describe the present rate of loss, driven by humans, as the sixth mass extinction.
IUCN Red List Categories
The International Union for Conservation of Nature (IUCN) was founded in 1948 and is headquartered at Gland, Switzerland. Its Red List of Threatened Species assesses extinction risk.
flowchart LR
NE["Not Evaluated (NE)"] --- DD["Data Deficient (DD)"]
LC["Least Concern (LC)"] --> NT["Near Threatened (NT)"]
NT --> VU["Vulnerable (VU)"]
VU --> EN["Endangered (EN)"]
EN --> CR["Critically Endangered (CR)"]
CR --> EW["Extinct in the Wild (EW)"]
EW --> EX["Extinct (EX)"]- “Threatened” = CR + EN + VU only.
- EW means the species survives only in captivity or as a naturalised population outside its historic range.
- DD is not a threat category; it means information is insufficient.
| Species (relevant to Chhattisgarh) | IUCN status (check the current Red List) |
|---|---|
| Wild water buffalo | Endangered |
| Tiger | Endangered |
| Asian elephant | Endangered |
| Indian pangolin | Endangered |
| White-rumped vulture, Indian vulture | Critically Endangered |
| Gaur, sloth bear | Vulnerable |
The Legal Framework: Biological Diversity Act, 2002
India enacted the Biological Diversity Act, 2002 to implement the CBD. It sets up a three-tier structure:
| Level | Body | Role |
|---|---|---|
| National | National Biodiversity Authority (NBA), Chennai (2003) | Approves access to Indian biological resources by foreigners and for IPR/patents |
| State | State Biodiversity Boards (SBBs) | Regulate commercial use by Indian entities; Chhattisgarh has its own board |
| Local | Biodiversity Management Committees (BMCs) in every local body | Prepare People’s Biodiversity Registers (PBRs) documenting local resources and knowledge |
- Access and Benefit Sharing (ABS): those who commercially use biological resources or associated traditional knowledge must share benefits with the communities that conserved them. This is India’s route to implementing the Nagoya Protocol.
- Biodiversity Heritage Sites can be notified by State Governments under the Act.
- The Biological Diversity (Amendment) Act, 2023 decriminalised many offences (replacing them with penalties), eased requirements for the codified traditional knowledge and AYUSH sector, and increased the role of the NBA and SBBs.
Memory Tricks
Don’t Confuse
| This | vs | That |
|---|---|---|
| Alpha diversity — within a community | vs | Beta diversity — turnover between communities |
| Endemic — found only in one region | vs | Endangered — at high risk of extinction (an IUCN category) |
| Hotspot — rich and threatened (1,500 + 70%) | vs | Megadiverse country — very rich, no threat criterion (17 countries) |
| Extinct in the Wild (EW) — survives in captivity | vs | Extinct (EX) — no individual left |
| NBA — Chennai, under Biological Diversity Act 2002 | vs | NTCA — tiger authority under the Wildlife (Protection) Act |
| Deccan Peninsula — largest biogeographic zone | vs | Western Ghats — a hotspot and a separate zone |
Common Mistakes
- “India has three biodiversity hotspots.” India has four: Sundaland is counted through the Nicobar Islands.
- “Hotspots are areas of high diversity.” Incomplete. They must also have lost at least 70% of original habitat.
- “Data Deficient is a threatened category.” No. Threatened = CR, EN, VU only.
- “Biodiversity decreases towards the equator.” The opposite: it generally increases towards the tropics.
- “The Central Indian highlands form a hotspot.” They do not.
- “IUCN is a UN agency.” No. IUCN is an international union of governments and NGOs, not a UN body.
Practice
All questions below are original practice questions written in CGPSC style. They are not previous-year questions.
Level 1: Foundation
- Name the three levels of biodiversity.
- How many biodiversity hotspots are there in the world, and how many include part of India?
- The National Biodiversity Authority is located at ______.
Answers
- Genetic, species and ecosystem diversity.
- 36 in the world; 4 include part of India.
- Chennai.
Level 2: Prelims MCQs
Q1. Consider the following statements regarding biodiversity hotspots:
- A region must contain at least 1,500 species of endemic vascular plants to qualify.
- A region must have lost at least 70% of its original natural vegetation to qualify.
- The Central Indian highlands, including Chhattisgarh, form one of India’s hotspots.
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 1 and 2 only
- (c) 2 and 3 only
- (d) 1, 2 and 3
Answer and explanation
Q2. Match List I (Hotspot) with List II (Indian region):
| List I | List II |
|---|---|
| A. Sundaland | 1. North-Eastern states |
| B. Indo-Burma | 2. Nicobar Islands |
| C. Western Ghats and Sri Lanka | 3. Sikkim, Uttarakhand, Himachal |
| D. Himalaya | 4. Kerala, Karnataka, Goa |
- (a) A-2, B-1, C-4, D-3
- (b) A-1, B-2, C-4, D-3
- (c) A-2, B-3, C-4, D-1
- (d) A-4, B-1, C-2, D-3
Answer and explanation
Q3. Which of the following IUCN Red List categories are classified as “threatened”?
- Critically Endangered
- Near Threatened
- Vulnerable
- Data Deficient
Select the correct answer using the code given below:
- (a) 1 and 3 only
- (b) 1, 2 and 3 only
- (c) 1, 3 and 4 only
- (d) 1, 2, 3 and 4
Answer and explanation
Q4. Most of Chhattisgarh falls in which biogeographic zone of India?
- (a) Semi-arid
- (b) Gangetic Plain
- (c) Deccan Peninsula
- (d) Western Ghats
Answer and explanation
Q5. Under the Biological Diversity Act, 2002, People’s Biodiversity Registers are prepared by:
- (a) The National Biodiversity Authority
- (b) State Biodiversity Boards
- (c) Biodiversity Management Committees
- (d) The Ministry of Tribal Affairs
Answer and explanation
Level 3: Mains Answer Writing
Q1. (60 words) What is a biodiversity hotspot? Name India’s hotspots.
Model answer outline
- Definition: A region with at least 1,500 endemic vascular plant species that has lost at least 70% of its original habitat (Myers, 1988; Conservation International). It is both rich and threatened.
- Global: 36 hotspots, about 2.5% of land area, more than half of plant species as endemics.
- India: Himalaya, Indo-Burma, Western Ghats and Sri Lanka, Sundaland (Nicobar).
Q2. (150–200 words) Discuss the major threats to biodiversity in central India, with special reference to Chhattisgarh. Suggest measures.
Model answer outline
- Intro: Chhattisgarh, in the Deccan Peninsula zone, has extensive sal and teak forests and species such as the wild buffalo, tiger, elephant and hill myna. Its forests are rich but under pressure.
- Threats (HIPPO):
- Habitat loss and fragmentation: mining (coal in the north, iron ore in the south), linear infrastructure and reservoirs break corridors; human–elephant conflict follows.
- Invasive species: Lantana suppresses native undergrowth and regeneration.
- Pollution: fly ash, mine runoff and industrial effluents in rivers.
- Over-harvesting and poaching: pangolin trade; unsustainable collection of some forest produce.
- Climate change: heat stress and changes in rainfall affect forest regeneration and fire frequency.
- Measures: protect and connect habitats (tiger and elephant reserves, corridors); remove Lantana and restore grasslands; enforce EIA and no-go areas; strengthen BMCs and PBRs with benefit sharing; involve communities through the Forest Rights Act; conservation breeding for the wild buffalo.
- Conclusion: Conservation succeeds in central India when it is linked to the livelihoods of forest-dwelling communities.
Quick Revision Table
| Fact | Detail |
|---|---|
| CBD definition | Art 2: within species, between species, of ecosystems |
| Levels | Genetic, species, ecosystem |
| α / β / γ | Within community / between communities / whole region (Whittaker) |
| India’s share | About 2.4% of land; about 7–8% of recorded species |
| Megadiverse countries | 17 (India is one) |
| Biogeographic zones | 10; largest = Deccan Peninsula (includes Chhattisgarh) |
| Hotspot concept | Norman Myers, 1988; Conservation International |
| Hotspot criteria | ≥1,500 endemic vascular plants and ≥70% habitat lost |
| Hotspots | 36 worldwide; 4 in India (Himalaya, Indo-Burma, Western Ghats–Sri Lanka, Sundaland) |
| Threats | HIPPO + climate change |
| IUCN | 1948; Gland, Switzerland; threatened = CR, EN, VU |
| Biological Diversity Act | 2002; NBA Chennai, SBBs, BMCs; amended 2023 |
| CG state animal / bird / tree | Wild water buffalo / hill myna / sal |
Key Takeaways
- Biodiversity has three levels: genetic, species, ecosystem.
- India is megadiverse: about 2.4% of land, about 7–8% of species, 10 biogeographic zones.
- A hotspot needs 1,500 endemic plants and 70% habitat loss; there are 36, and 4 touch India. Chhattisgarh is in none.
- HIPPO plus climate change explains biodiversity loss; habitat loss leads.
- IUCN “threatened” means CR, EN and VU; the Red List is an assessment, not a law.
- The Biological Diversity Act, 2002 works through NBA, SBBs and BMCs, with access and benefit sharing.
What’s Next
- Climate Change — the newest and fastest-growing threat to biodiversity
- Environmental Conventions — CBD, CITES, Ramsar and the Kunming-Montreal framework
- Biodiversity and Conservation — protected areas, in-situ and ex-situ methods
- Forests and Wildlife of Chhattisgarh — the state’s national parks, sanctuaries and reserves