Environment Quick Revision Part-2

by | Feb 2, 2025 | APPSC Group-2 Mains Paper-2 Environment

Biodiversity

  • Biodiversity refers to the variety of life on Earth, including all living organisms, ecosystems, and genetic diversity.

Levels of Biodiversity

  • Genetic Diversity: Variation in genes within a species (e.g., different breeds of dogs).
  • Species Diversity: Variety of species in a region (e.g., plants, animals, fungi).
  • Ecosystem Diversity: Variety of ecosystems in a region (e.g., forests, deserts, wetlands).

Measurement of Biodiversity

  • Species Richness
    • The total number of different species in a given area.
    • Example: If a forest has 50 bird species and a grassland has 20, the forest has higher species richness.
    • Alpha Diversity: Diversity within a single ecosystem or habitat.
    • Beta Diversity: Comparison of species diversity between ecosystems.
    • Gamma Diversity: Total biodiversity of a large geographical region (e.g., a country).
  • Species Evenness
    • Measures how evenly individuals are distributed among different species in an ecosystem.
    • Example: If an ecosystem has 100 deer and 100 tigers, it has high evenness; if it has 190 deer and 10 tigers, evenness is low.

Quick Facts

  • In terms of species richness, India is ranked
    • 7th in mammals
    • 9th in birds
    • 5th in reptiles
  • As per India Biodiversity Portal, 2021, along with species richness, India also possesses high rates of endemism i.e.,
    • 4.5% of birds
    • 12.6% of mammals
    • 45.8% of reptiles
    • 55.8% of amphibians
    • 33% of plants are endemic.

Importance of Biodiversity

  • Ecosystem Services:
    • Provisioning: Food, water, timber, and medicinal resources.
    • Regulating: Climate regulation, flood control, and pollination.
    • Cultural: Recreational, spiritual, and aesthetic benefits.
    • Supporting: Nutrient cycling, soil formation, and primary production.
  • Economic Value: Biodiversity supports industries like agriculture, fisheries, and tourism.
  • Scientific Value: Provides insights into evolution, genetics, and ecology.
  • Resilience: Diverse ecosystems are more stable and resilient to disturbances.

Threats to Biodiversity

  • Habitat Destruction: Deforestation, urbanization, and agriculture.
  • Pollution: Air, water, and soil contamination.
  • Climate Change: Rising temperatures, sea levels, and extreme weather.
  • Overexploitation: Overfishing, hunting, and logging.
  • Invasive Species: Non-native species that disrupt ecosystems.
  • Population Growth: Increased demand for resources.

Conservation of Biodiversity

In-Situ Conservation:

  • Protecting species in their natural habitats.
  • Examples:
    • National Parks and Wildlife Sanctuaries: Protected areas for wildlife.
    • Biosphere Reserves: Areas that conserve biodiversity and promote sustainable development.
    • Community Reserves: Managed by local communities.

Ex-Situ Conservation:

  • Protecting species outside their natural habitats.
  • Examples:
    • Zoos and Botanical Gardens: Captive breeding and preservation.
    • Seed Banks: Storage of seeds for future use.
    • Cryopreservation: Freezing genetic material for conservation.

Red Data Book

  • Definition: The Red Data Book is a document maintained by the International Union for Conservation of Nature (IUCN) that lists species at risk of extinction.
  • Purpose: It serves as a comprehensive inventory of the conservation status of species and helps guide conservation efforts.
  • Categories: Species are classified based on their risk of extinction, using the IUCN Red List Categories and Criteria.

IUCN Red List Categories

IUCN CategoryDefinitionExample
Extinct (EX)No individuals remain.Tasmanian tiger.
Extinct in the Wild (EW)Survives only in captivity.Spix’s macaw.
Critically Endangered (CR)Extremely high risk of extinction.Amur leopard, Sumatran orangutan.
Endangered (EN)Very high risk of extinction.Blue whale, Asian elephant.
Vulnerable (VU)High risk of extinction.Giant panda, polar bear.
Near Threatened (NT)Likely to become endangered soon.American bison.
Least Concern (LC)Widespread and abundant.Common pigeon, house sparrow.
Data Deficient (DD)Insufficient data to assess risk.Many deep-sea species.
Not Evaluated (NE)Not yet assessed by IUCN.Many lesser-known species.

Biodiversity Hotspots

  • Biodiversity hotspots are regions of the world that are exceptionally rich in plant and animal life, but also face significant threats of habitat loss.
  • Key Criteria for a Biodiversity Hotspot:
    • High Endemism: Must contain at least 1,500 species of vascular plants as endemics (found nowhere else on Earth).
    • High Degree of Threat: Must have lost at least 70% of its original natural vegetation.
  • There are 36 globally recognized biodiversity hotspots. The following are biodiversity hot spots of india.
  • The Himalayas:
    • Extends across the Himalayan ranges in India, Bhutan, Nepal, and southern China.
    • Key Species: Snow leopard, red panda, Himalayan monal (bird), medicinal plants like Yew and Rhododendron.
  • Indo Burma Region:
    • Extends from Eastern Bangladesh to Malaysia including north-eastern states.
    • Key Species: Indian python, hoolock gibbon, golden langur, various orchid species.
  • Western Ghats and Srilanka:
    • Spreads along the western coastline of India through Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu and highlands of southwestern Sri Lanka.
    • Highest concentration of species in Western Ghats is in Agasthyamalai hills.
    • Key Species: Lion-tailed macaque, Nilgiri tahr, Malabar civet, king cobra.
  • Sundaland:
    • Includes the Andaman and Nicobar Islands, which are part of the larger Sundaland hotspot.
    • Contains high marine and terrestrial biodiversity.
    • Key Species: Dugong (sea cow), Nicobar pigeon, saltwater crocodile.

India’s Two Realms

  • Indo-Malayan Realm: Covers most of India, including the Himalayas, Western Ghats, and the Deccan Plateau.
  • Paleartic Realm: Includes the high-altitude regions of the Himalayas (e.g., Ladakh, parts of Jammu & Kashmir).

Five Biomes of India

  • Tropical Rainforest: Western Ghats and Northeast India.
  • Tropical Deciduous Forest: Central and Eastern India.
  • Desert: Thar Desert in Rajasthan.
  • Temperate Forest: Himalayan regions.
  • Grassland: Deccan Plateau and Himalayan meadows.

India’s Ten Bio-geographic Zones

  • Trans-Himalayan: Cold deserts of Ladakh and Spiti.
  • Himalayan: The Himalayan mountain range.
  • Indian Desert: Thar Desert in Rajasthan.
  • Semi-Arid: Parts of Gujarat, Rajasthan, and Karnataka.
  • Western Ghats: Mountain range along the west coast.
  • Deccan Peninsula: Central and Southern India.
  • Gangetic Plain: Fertile plains of North India.
  • North-East India: Biodiversity hotspot with dense forests.
  • Coasts: Coastal regions along the Arabian Sea and Bay of Bengal.
  • Islands: Andaman & Nicobar and Lakshadweep Islands.

25 Biogeographic Provinces of India

India is divided into 10 Biogeographic Zones and further into 25 Biogeographic Provinces based on climate, geography, and biodiversity.

1. Trans-Himalaya (Zone 1)

  • 1A. Ladakh Mountains
  • 1B. Tibetan Plateau
  • 1C. Sikkim

2. Himalaya (Zone 2)

  • 2A. North-West Himalaya
  • 2B. West Himalaya
  • 2C. Central Himalaya
  • 2D. East Himalaya

3. Desert (Zone 3)

  • 3A. Thar Desert
  • 3B. Kutch

4. Semi-Arid (Zone 4)

  • 4A. Punjab Plains
  • 4B. Gujarat-Rajputana

5. Western Ghats (Zone 5)

  • 5A. Malabar Coast
  • 5B. Western Ghat Mountains

6. Deccan Peninsula (Zone 6)

  • 6A. Central Highlands
  • 6B. Chhota Nagpur
  • 6C. Eastern Highlands
  • 6D. Central Plateau
  • 6E. Deccan South

7. Gangetic Plains (Zone 7)

  • 7A. Upper Gangetic Plains
  • 7B. Lower Gangetic Plains

8. Coasts (Zone 8)

  • 8A. East Coast
  • 8B. West Coast

9. North-East (Zone 9)

  • 9A. Brahmaputra Valley
  • 9B. North-East Hills

10. Islands (Zone 10)

  • 10A. Andaman Islands
  • 10B. Nicobar Islands