1. Levels of Biodiversity
Biodiversity refers to the variety and variability among living organisms and the ecological complexes in which they occur. It is generally studied at three levels:
- Genetic Diversity: Variation in genes within a single species (e.g., thousands of varieties of rice in India).
- Species Diversity: The variety of species within a region (e.g., the number of different types of trees in a forest).
- Ecosystem Diversity: The variety of habitats and ecological processes (e.g., deserts, rainforests, mangroves).
2. Value of Biodiversity
Biodiversity is essential for the sustainable functioning of the biosphere. Its values are categorized as:
- Consumptive Use Value: Products harvested directly (food, firewood, medicines).
- Productive Use Value: Commercially usable products (timber, leather, wool).
- Social/Ethical Value: The right of all species to exist and the cultural significance of certain plants/animals.
- Aesthetic Value: The beauty of nature and eco-tourism.
3. India as a Mega-diversity Nation
India is one of the 17 mega-diversity countries in the world. Although India has only 2.4% of the world's land area, it accounts for 7-8% of the global recorded species.
India’s Hotspots: Western Ghats, Eastern Himalayas, Indo-Burma region, and Sundaland.
4. Threats to Biodiversity
Human activities are causing the sixth mass extinction. Major threats include:
- Habitat Loss & Fragmentation: Deforestation for agriculture and urban development.
- Poaching: Illegal hunting for skins, horns, and tusks.
- Man-Wildlife Conflict: Destruction of habitats forces animals into human settlements (e.g., elephants in farms).
- Invasive Species: Non-native species outcompeting local ones (e.g., Lantana camera, Parthenium).
5. In-situ and Ex-situ Conservation
Conservation strategies are broadly divided into two types:
| Feature | In-situ (On-site) | Ex-situ (Off-site) |
|---|---|---|
| Definition | Conserving species in their natural habitat. | Conserving species outside their natural habitat. |
| Approach | Protecting the entire ecosystem. | Protecting individual species. |
| Examples | National Parks, Wildlife Sanctuaries, Biosphere Reserves. | Zoos, Botanical Gardens, Seed Banks, Gene Banks. |
6. Exam Focus Enhancements
- Hotspots Criteria: To be a hotspot, a region must contain at least 1,500 species of vascular plants as endemics and must have lost at least 70% of its original habitat.
- Endemic vs. Endangered: Know the difference. Endemic means found only in one place; Endangered means at risk of extinction.
- Red Data Book: Mention the IUCN Red List when discussing endangered species to show technical knowledge.
- Confusing National Parks & Sanctuaries: National Parks are strictly for wildlife and no human activity is allowed. In Sanctuaries, limited human activity (like collection of forest products) may be permitted.
- In-situ vs Ex-situ: Students often put Botanical Gardens under In-situ. It is Ex-situ because plants are brought there from elsewhere.
- Ignoring Genetic Diversity: Most students only focus on species. Don't forget that diversity within a species is just as important for survival.
Q: What is a Keystone Species?
A: A species that has a disproportionately large effect on its environment relative to its abundance (e.g., Tigers in a forest).
Q: Why is India called a Mega-diverse nation?
A: Due to its varied climatic conditions, topographic features, and rich tradition of indigenous knowledge, India hosts a massive variety of flora and fauna.