Biodiversity and Conservation

Key Concepts

What is Biodiversity?

Immense heterogeneity exists at all levels of biological organisation. The term was popularised by sociobiologist Edward Wilson.

Genetic Diversity: Variation within a species (e.g., 50,000 strains of rice in India; Rauwolfia vomitoria producing different concentrations of reserpine).
Species Diversity: Diversity at the species level (e.g., Western Ghats have more amphibians than Eastern Ghats).
Ecological Diversity: Diversity at ecosystem levels (e.g., India has deserts, rain forests, mangroves, coral reefs).

Global and Indian Biodiversity

Robert May's Estimate Robert May places the global species diversity at about 7 million, which is considered one of the most scientifically sound estimates.

Named Species: ~1.5 million. > 70% are animals, 22% are plants. Among animals, > 70% are insects.
India: Has 2.4% of world's land but 8.1% of global species diversity. One of the 12 mega diversity countries. ~45,000 plant and ~90,000 animal species recorded.

Patterns of Biodiversity

Latitudinal Gradients: Species diversity decreases from equator to poles.
- Tropics (23.5° N to 23.5° S): Harbour more species. e.g., Amazon rain forest (greatest biodiversity).
- Reasons for Tropical Richness: (a) More evolutionary time (undisturbed by glaciations). (b) Constant, predictable environment (promotes niche specialisation). (c) More solar energy (higher productivity).
Species-Area Relationship: Popularised by Alexander von Humboldt.
- Species richness increases with explored area but up to a limit (Rectangular Hyperbola).
- Equation: log S = log C + Z log A.
- Slope (Z) is usually 0.1 to 0.2, but steeper (0.6 to 1.2) for very large areas like continents.

Importance of Species Diversity

Ecosystem Stability: Diverse communities are more productive and resistant to invasions/disturbances (Tilman's experiments).

Rivet Popper Hypothesis Proposed by Paul Ehrlich, this hypothesis uses an airplane analogy to explain how the loss of even a few key species can compromise ecosystem integrity.

Rivet Popper Hypothesis (Paul Ehrlich): Analogizes species to rivets in an airplane. Losing 'wing rivets' (key species) is catastrophic for ecosystem functioning.

Loss of Biodiversity

The Sixth Extinction: Currently in progress; 100 to 1,000 times faster than pre-human rates.

The Evil Quartet The four major causes of biodiversity loss are Habitat Loss, Over-exploitation, Alien Species Invasions, and Co-extinctions.

The Evil Quartet (Causes):
1. Habitat Loss and Fragmentation: Most important cause (e.g., Amazon forest being cleared for soya beans).
2. Over-exploitation: e.g., Steller's sea cow, passenger pigeon.
3. Alien Species Invasions: e.g., Nile perch in Lake Victoria; Lantana, Water hyacinth in India.
4. Co-extinctions: Extinction of host leads to extinction of obligatory parasites/mutualists.

Biodiversity Conservation

Why Conserve?
- Narrowly Utilitarian: Direct economic benefits (food, medicine, fiber).
- Broadly Utilitarian: Ecosystem services (20% O2 from Amazon, pollination, aesthetic value).
- Ethical: Moral duty to protect every species.
How to Conserve?
1. In Situ (On site): Protecting the whole ecosystem.
  - Biodiversity Hotspots: Regions with high species richness and endemism (34 globally; 3 in India: Western Ghats-Sri Lanka, Indo-Burma, Himalaya).
  - Protected Areas: 14 Biosphere Reserves, 90 National Parks, 448 Wildlife Sanctuaries.
  - Sacred Groves: Veneration of forest patches (e.g., Khasi/Jaintia Hills).
2. Ex Situ (Off site): Threatened species kept in special settings.
  - Zoological parks, Botanical gardens, Wildlife safari parks.
  - Cryopreservation (gametes), Tissue culture, Seed banks.
Global Efforts: The Earth Summit (Rio, 1992) and World Summit (Johannesburg, 2002).

Key Concepts

Immense heterogeneity exists at all levels of biological organisation. The term was popularised by sociobiologist Edward Wilson.

Genetic Diversity: Variation within a species (e.g., 50,000 strains of rice in India; Rauwolfia vomitoria producing different concentrations of reserpine).

Species Diversity: Diversity at the species level (e.g., Western Ghats have more amphibians than Eastern Ghats).

Ecological Diversity: Diversity at ecosystem levels (e.g., India has deserts, rain forests, mangroves, coral reefs).

Robert May's Estimate Robert May places the global species diversity at about 7 million, which is considered one of the most scientifically sound estimates.

Named Species: ~1.5 million. > 70% are animals, 22% are plants. Among animals, > 70% are insects.

India: Has 2.4% of world's land but 8.1% of global species diversity. One of the 12 mega diversity countries. ~45,000 plant and ~90,000 animal species recorded.

Latitudinal Gradients: Species diversity decreases from equator to poles.

Tropics (23.5° N to 23.5° S): Harbour more species. e.g., Amazon rain forest (greatest biodiversity).
Reasons for Tropical Richness: (a) More evolutionary time (undisturbed by glaciations). (b) Constant, predictable environment (promotes niche specialisation). (c) More solar energy (higher productivity).

Species-Area Relationship: Popularised by Alexander von Humboldt.

Species richness increases with explored area but up to a limit (Rectangular Hyperbola).
Equation: log S = log C + Z log A.
Slope (Z) is usually 0.1 to 0.2, but steeper (0.6 to 1.2) for very large areas like continents.

Ecosystem Stability: Diverse communities are more productive and resistant to invasions/disturbances (Tilman's experiments).

Rivet Popper Hypothesis Proposed by Paul Ehrlich, this hypothesis uses an airplane analogy to explain how the loss of even a few key species can compromise ecosystem integrity.

Rivet Popper Hypothesis (Paul Ehrlich): Analogizes species to rivets in an airplane. Losing 'wing rivets' (key species) is catastrophic for ecosystem functioning.

The Sixth Extinction: Currently in progress; 100 to 1,000 times faster than pre-human rates.

The Evil Quartet The four major causes of biodiversity loss are Habitat Loss, Over-exploitation, Alien Species Invasions, and Co-extinctions.

The Evil Quartet (Causes):

Habitat Loss and Fragmentation: Most important cause (e.g., Amazon forest being cleared for soya beans).
Over-exploitation: e.g., Steller's sea cow, passenger pigeon.
Alien Species Invasions: e.g., Nile perch in Lake Victoria; Lantana, Water hyacinth in India.
Co-extinctions: Extinction of host leads to extinction of obligatory parasites/mutualists.

Why Conserve?

Narrowly Utilitarian: Direct economic benefits (food, medicine, fiber).
Broadly Utilitarian: Ecosystem services (20% O2 from Amazon, pollination, aesthetic value).
Ethical: Moral duty to protect every species.

How to Conserve?

In Situ (On site): Protecting the whole ecosystem.
- Biodiversity Hotspots: Regions with high species richness and endemism (34 globally; 3 in India: Western Ghats-Sri Lanka, Indo-Burma, Himalaya).
- Protected Areas: 14 Biosphere Reserves, 90 National Parks, 448 Wildlife Sanctuaries.
- Sacred Groves: Veneration of forest patches (e.g., Khasi/Jaintia Hills).
Ex Situ (Off site): Threatened species kept in special settings.
- Zoological parks, Botanical gardens, Wildlife safari parks.
- Cryopreservation (gametes), Tissue culture, Seed banks.

Global Efforts: The Earth Summit (Rio, 1992) and World Summit (Johannesburg, 2002).

Biodiversity and Conservation

Biodiversity and Conservation

Key Concepts

What is Biodiversity?

Global and Indian Biodiversity

Patterns of Biodiversity

Importance of Species Diversity

Loss of Biodiversity

Biodiversity Conservation

On this page

Biodiversity and Conservation

Biodiversity and Conservation

Key Concepts

What is Biodiversity?

Global and Indian Biodiversity

Patterns of Biodiversity

Importance of Species Diversity

Loss of Biodiversity

Biodiversity Conservation

On this page