NCERT-Book-for-Class-9-Geography-Chapter-5

Biodiversity in India

  • India is one of the 12 mega bio-diversity countries globally.

  • Approximately 47,000 plant species; ranks 10th in the world, 4th in Asia.

  • 15,000 flowering plants, making up 6% of global total.

  • 90,000 animal species, rich marine and freshwater fish diversity.

Natural Vegetation

  • Virgin Vegetation: Plant communities that grow naturally without human aid.

  • Endemic Species: Native species found only in India.

  • Exotic Plants: Species introduced from outside India.

  • Flora and Fauna: Terms used to refer to plants and animals in a region.

Factors Affecting Natural Vegetation

Relief and Land

  • Type of land influences vegetation; fertile lands are used for agriculture.

  • Undulating terrains support grasslands and woodlands.

Soil

  • Different soil types provide the basis for varying vegetation:

    • Sandy soils: Support cacti and thorny bushes.

    • Marshy soils: Support mangroves.

Climate

  • Temperature: Determines vegetation types; changes with altitude.

  • Photoperiod: Longer sunlight duration enhances plant growth.

    • Table of Temperature Characteristics for Vegetation Zones:

      • Tropical: >24°C no frost

      • Subtropical: 17°C to 24°C, rare frost

      • Temperate: 7°C to 17°C, some frost

      • Alpine: <7°C, snow presence

Precipitation

  • Rainfall patterns (monsoons) affect vegetation density; more rain leads to denser forests.

Types of Vegetation in India

  1. Tropical Evergreen Forests

    • Found in regions with heavy rainfall (Western Ghats, islands).

    • Trees can reach heights of 60 meters and retain foliage year-round.

  2. Tropical Deciduous Forests

    • Rainfall between 100 cm to 200 cm.

    • Trees shed leaves during dry summer; include teak and sal.

  3. Thorn Forests and Scrubs

    • Found in arid regions (<70 cm rainfall); include acacias and cacti.

    • Adapted to conserve water (thick leaves, deep roots).

  4. Montane Forests

    • Change with altitude; include broad-leaf and coniferous trees.

    • Critical for supporting various wildlife species.

  5. Mangrove Forests

    • Found along tidal coasts; important for delta ecosystems.

    • Home to unique wildlife like the Royal Bengal Tiger.

Wildlife in India

  • Rich in fauna with ~90,000 animal species, including 2,000 bird species.

  • Wildlife Conservation: Wildlife Protection Act 1972; designated reserves.

  • Endangered species due to habitat loss, pollution, and illegal hunting.

Conservation Efforts

  • Establishment of 18 biosphere reserves, including Sundarbans and Nanda Devi.

  • Ongoing projects like Project Tiger aim to protect specific species.

Important Activities and Questions

  • Activities include identifying local medicinal plants and observing forest types in neighborhoods.

  • Questions on factors affecting wildlife distribution, conservation measures, and biodiversity importance.

Types of Vegetation in India

  • Tropical Evergreen ForestsFound in regions with heavy rainfall, such as the Western Ghats and islands.

    • Trees can reach heights of up to 60 meters and retain foliage year-round, creating dense canopies.

    • Rich in biodiversity, featuring a wide range of species including commercially important hardwoods.

  • Tropical Deciduous ForestsFound in areas with rainfall between 100 cm to 200 cm.

    • Trees like teak and sal shed their leaves during the dry summer months, allowing for water conservation.

    • Provide habitat for various wildlife species, including elephants and tigers.

  • Thorn Forests and ScrubsAdapted to arid conditions with less than 70 cm of rainfall.

    • Characterized by flora such as acacias and cacti, which conserve water through thick leaves and deep root systems.

    • Often found in the states of Rajasthan and Gujarat.

  • Montane ForestsTransition with altitude, including a mix of broad-leaf and coniferous trees at higher elevations.

    • Critical for supporting diverse wildlife and contributing to local watershed health.

    • Regions such as the Himalayas exemplify this type of vegetation.

  • Mangrove ForestsFound along tidal coasts, playing a key role in coastal ecosystems.

    • Home to unique wildlife, including the Royal Bengal Tiger and various bird species.

    • Important for protecting shorelines from erosion and providing nursery grounds for marine life.