Biodiversity and its conservation Introduction, definition, types. Biogeographical classification of India.

1. Introduction

• Biodiversity (biological diversity) represents the variety of life forms on Earth and their complex interactions. It includes all living organisms—from microscopic bacteria to giant mammals—and the ecosystems they form. Biodiversity ensures the functioning of ecosystems, supports ecological balance, regulates climate, purifies air and water, and maintains soil fertility.
• Human activities—such as deforestation, industrialization, pollution, habitat fragmentation, overexploitation of species, and climate change—have significantly threatened biodiversity. Conservation of biodiversity has therefore become a global priority to maintain ecological stability, evolutionary processes, and sustainable development.

2. Definition of Biodiversity

• 2.1 Convention on Biological Diversity (CBD, 1992) “Biodiversity is the variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part.”
• 2.2 Simple Definition: Biodiversity refers to the total variety and variability of genes, species, and ecosystems found in a particular region or on Earth as a whole.

2.3 Key Features of Biodiversity

• Occurs at multiple levels
• Represents life in all forms
• Includes functional diversity (roles of species)
• Ensures stability and productivity of ecosystems

3. Types of Biodiversity: Biodiversity is commonly categorized into three major levels:

3.1 Genetic Diversity

Genetic diversity refers to the variation of genes within a species.
It includes:

• Differences among individuals
• Variations between populations
• Genetic makeup that determines traits

Examples:

• Thousands of rice varieties in India
• Different breeds of cattle, dogs, and poultry
• Variability in mango or banana varieties

Importance:

• Increases adaptability to environmental changes
• Helps in crop improvement and disease resistance
• Essential for evolution through natural selection

3.2 Species Diversity

Species diversity refers to the variety of species within a region.

It includes:

• Species richness – number of species
• Species evenness – relative abundance
• Species dominance

Examples:

• India has >1.02 lakh animal species and 45,000 plant species
• Amazon rainforest has world’s highest species diversity

Importance:

• Maintains ecological balance
• Supports ecosystems through predator–prey and pollinator relationships

3.3 Ecosystem Diversity

Ecosystem diversity refers to the variety of habitats, ecosystems, and ecological processes.

It includes:

• Forest ecosystems
• Grasslands
• Deserts
• Wetlands
• Marine ecosystems
• Mountain ecosystems

Importance:

• Provides different ecological niches
• Maintains overall resilience of the biosphere
• Ensures nutrient cycling and climate regulation

4. Biogeographical Classification of India

India’s unique location, varied climate, and diverse topography contribute to its enormous biodiversity.
India is recognized as:

• One of the 17 megadiverse countries
• Having 8% of the world’s biodiversity
• A region with two global biodiversity hotspots (Western Ghats, Indo-Burma region)

The Wildlife Institute of India (Rodgers & Panwar, 1988) classified India into 10 biogeographicalzones and 25 biotic provinces based on climatic and ecological features.

1. Trans-Himalayan Zone

Characterized by cold deserts and high altitudes.
Vegetation is sparse, and fauna is specially adapted to harsh climates.
Examples: Ladakh, Spiti Valley
Key Species: Snow leopard, wild yak, Tibetan antelope

2. Himalayan Zone

Rich in alpine, temperate, and subtropical forests with high species diversity and endemism.
Examples: Uttarakhand, Himachal Pradesh, Jammu & Kashmir
Key Species: Himalayan tahr, musk deer, red panda

3. Desert Zone

Includes hot and cold deserts, with low rainfall and xerophytic vegetation.
Examples: Rajasthan, Kutch
Key Species: Camel, desert fox, spiny-tailed lizard

4. Semi-Arid Zone

A transition between desert and dry deciduous forests; has scrub vegetation.
Examples: Punjab, Haryana, Gujarat
Key Species: Blackbuck, nilgai

5. Western Ghats Zone

A global biodiversity hotspot with high endemism and dense evergreen forests.
Examples: Kerala, Karnataka, Maharashtra
Key Species: Lion-tailed macaque, Nilgiri tahr

6. Deccan Peninsula

The largest zone, dominated by dry and moist deciduous forests and scrublands.
Examples: Madhya Pradesh, Chhattisgarh, Odisha
Key Species: Tiger, gaur, Indian wild dog (dhole)

7. Gangetic Plains

Extensive fertile alluvial plains with high human population density.
Examples: Uttar Pradesh, Bihar, West Bengal
Key Species: Gangetic river dolphin, swamp deer

8. North-East India

High rainfall, dense forests, and extremely rich biodiversity with many endemic species.
Examples: Assam, Meghalaya, Manipur, Tripura
Key Species: Hoolock gibbon, one-horned rhinoceros

9. Coastal Zone

Includes beaches, mangroves, lagoons, and estuaries along both coasts.
Examples: Eastern and Western coastal states
Key Species: Olive Ridley turtles, mangrove flora & fauna

10. Islands Zone

Comprises Andaman, Nicobar, and Lakshadweep Islands with coral reefs and isolated ecosystems.
Key Species: Dugong, Nicobar pigeon, coral species

Key Biodiversity Facts for Exams

• India = 2.4% of world’s land → 8% of world’s biodiversity.
• India has two biodiversity hotspots: Western Ghats & Indo-Burma region.
• Biogeographical classification by Rodgers & Panwar (1988).
• India has 10 biogeographical zones. 45,000 plant species & >1,02,000 animal species in India.

• Coral reefs = most productive marine ecosystems.
• Western Ghats have highest endemism in India.