Biodiversity Notes with PDF

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1. Biodiversity: Definition, Measurement, and Importance

• Definition:
  • The variety of living things (plants and animals) found in an ecosystem.
  • Specifically described as the range of different species in an environment.
• Measurement (Proposed by Whittaker, 1960):
  • Alpha (α) diversity: Diversity within a specific area/ecosystem.
  • Beta (β) diversity: Diversity between ecosystems.
  • Gamma (γ) diversity: Overall diversity across a large region.
• Importance:
  • The most significant aspect is the maintenance and balance of the ecosystem.

2. Threats to Biodiversity

• Primary Cause: Destruction of natural habitats (e.g., deforestation for agriculture, wetland destruction for construction, dam building). This is the largest threat.
• Other Major Threats:
  • Habitat fragmentation.
  • Environmental pollution.
  • Introduction of exotic (alien) species.
  • Over-exploitation of resources.
  • Climate change and global warming.
  • Unsustainable practices like Jhum cultivation (shifting cultivation).
• General Consensus: Biodiversity loss is due to a combination of all the above factors.

3. Conservation of Biodiversity

• In-situ Conservation (On-site):
  • Conservation of species in their natural habitat.
  • Methods: Biosphere Reserves, National Parks, Wildlife Sanctuaries, Sacred Groves.
  • Note: Botanical Gardens are NOT an example of in-situ conservation.
• Ex-situ Conservation (Off-site):
  • Conservation of species away from their natural habitats.
  • Methods: Zoos, Aquaria, Botanical Gardens, Seed Banks.
  • Cryopreservation: Storing seeds, pollen, tissue, etc., in liquid nitrogen at CryoBanks.
• Policy and Law:
  • The Government of India and the Norwegian Government established a “Centre for Biodiversity Policy and Law” in Chennai at the National Biodiversity Authority.

4. Biodiversity Hotspots

• Definition: Regions with a high degree of endemic species (not found anywhere else) that are under threat.
• Global Context:
  • Cover only 2.5% of the Earth’s landmass.
  • Contain over half of the world’s plant species and nearly 43% of bird, mammal, reptile, and amphibian species.
  • Are NOT located only in tropical regions.
• India’s Hotspots (Four):
  1. The Himalayas (Eastern Himalayas) – a confirmed hotspot.
  2. Indo-Burma region (includes North-Eastern India and the Andaman Islands).
  3. Sundaland (includes the Nicobar Islands).
  4. Western Ghats – regarded as the most biodiversity-rich area in India.
  • Clarification: The statement that India’s hotspots are only the Eastern Himalayas and Western Ghats is incomplete.

5. Species Extinction & Endangerment

• Factors Leading to Extinction:
  • Factors that increase risk: Large body size, narrow niche (being a specialist, e.g., Koala), lack of genetic variability.
  • A broad niche (being a generalist) is NOT responsible for extinction; it helps species survive.
  • Human activities causing population decline (especially in birds): Large-scale reduction in habitats; large-scale use of pesticides, chemical fertilizers, and mosquito repellents (e.g., DDT).
• Conservation Status (Red Data Book):
  • Published by the IUCN (International Union for Conservation of Nature).
  • Contains lists of threatened and endangered species.
  • Does NOT contain lists of endemic species or protected sites.
• Examples of Endangered Species in India:
  • Birds: Great Indian Bustard, Siberian Crane, Sociable Lapwing.
  • Mammals: Musk Deer, Red Panda, Asiatic Wild Ass, Snow Leopard, Lion-tailed Macaque, Asiatic Wild Dog, Hoolock Gibbon, Golden Langur.
  • Note: The Desert Cat is not classified as endangered (it is vulnerable).

6. Ecosystems and Patterns

• Regions of High Biodiversity:
  • Maximum biodiversity is found in Tropical Rainforests.
  • Tropical Evergreen Forests have the maximum plant diversity among forest types.
  • Coral Reefs also have very high diversity.
• Global Pattern: Latitudinal Gradient
  • Biodiversity generally increases towards the equator.
  • Influenced by climate, elevation, soil, and geography.
• Important Biodiversity Sites in India:
  • Silent Valley (Kerala): In the Western Ghats; considered the richest biodiversity in India; a National Park.
  • Valley of Flowers (Uttarakhand): In the Chamoli region.
  • Sambhar Lake (Rajasthan): India’s largest inland saline wetland.
  • Coral Reefs: India has four main areas (Andaman and Nicobar Islands, Gulf of Kachchh, Gulf of Mannar, Lakshadweep) covering approx. 5,790 km².

7. Wetlands and the Ramsar Convention

• The Ramsar Convention:
  • An international treaty (signed in 1971, Ramsar, Iran) for the conservation and sustainable use of wetlands.
  • World Wetlands Day is observed on February 2nd.
• Ramsar Sites in India:
  • India has 49 designated Ramsar sites (as of provided data).
  • Examples: Chilka Lake (Odisha), Keoladeo (Rajasthan), Wuller Lake (J&K), Loktak Lake (Manipur).
  • Kabartal Wetland (Begusarai, Bihar) is Bihar’s first Ramsar site (designated July 21, 2020).

8. Additional Conservation Mechanisms & Facts

• Biosphere Reserves: Scientifically significant areas for conserving genetic diversity; the most important strategy for conserving biodiversity together with traditional human life. India has 18.
• The Cartagena Protocol:
  • A global agreement on biosafety for Living Modified Organisms (LMOs).
  • Adopted in 2000, came into force in 2003. India is a party.
• Land Degradation Neutrality (LDN):
  • India aims to achieve LDN by 2030 (balancing degradation with restoration).
• Regional Example: Sikkim
  • Became part of India in 1975.
  • Considered a “botanist’s paradise” with high biodiversity.
  • Main population: Lepchas, Bhotias, and Nepalis.
• General Facts:
  • International Biodiversity Day: Celebrated on May 22nd (commemorates the adoption of the Convention on Biological Diversity in 1992).
  • Defining Extinction (IUCN): A species is considered extinct if not seen in its natural habitat for 50 years.
  • Tallest Tree: Sequoia (Redwood) in California, U.S.A., up to 115.5 meters (379 feet).
• Specific Threat: Coral Bleaching
  • The most effective factor is a rise in the normal temperature of seawater.

Know More About Biodiversity:

• Biodiversity – Old Year Questions
• Biodiversity One Liner Questions & Answers