Unit 4: Biodiversity and its Conservation
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.
Biodiversity Hotspots: Regions with high species richness and high endemism (species found nowhere else) that are under threat.
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:
6. Exam Focus Enhancements
Exam Tips
- 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.
Common Mistakes
- 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.
Frequently Asked Questions
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.