Biogeographic Zones

A biogeographic zone is defined as a geographical area which is characterized by specific environmental and unique flora and fauna adapted to that region. India is divided into 10 biogeographic zones as per the plan proposed by Rogers and Panwar in 1986 for conservation purposes. The zones are further divided into 27 provinces. The zones include the Trans-Himalayan, the Himalayan, the Northwestern Desert, the Western Ghats, etc. These zones are vital for biodiversity conservation, sustainable development, and environmental planning, but face challenges such as habitat loss, deforestation, climate change, invasive species, and human-wildlife conflict.

A biogeographic zone refers to a distinct geographical area with a specific assemblage of plants, animals, and other organisms that are adapted to the particular environmental conditions of that region. In 1986, Rogers and Panwar from the Wildlife Institute of India (WII) proposed a plan to categorize India biogeographically. The classification was formulated as a part of India's conservation and environmental management efforts. This plan created 10 biogeographic zones across India, with each zone being additionally divided into 27 biogeographic provinces. The classification of biogeographic zones in India is essential for biodiversity conservation, sustainable development, and environmental planning.

India's diverse landscape is classified into 10 distinct biogeographic zones, each characterized by unique ecological features and biodiversity. These zones are essential for understanding the distribution of flora and fauna across the country. The Trans-Himalayan region encompasses the high-altitude landscapes of Ladakh and Himachal Pradesh, featuring cold deserts and alpine meadows. The Himalayan region, extending from Jammu & Kashmir to Arunachal Pradesh, presents diverse ecosystems from subtropical forests to alpine meadows. The Indian Desert region, with its arid expanses, hosts xerophytic plants and thorny shrubs. Other zones, like the Western Ghats, Deccan Plateau, Gangetic Plain, Central Highlands, Northeast Region, and Islands, exhibit distinct vegetation influenced by topography and climate.

India is characterized by diverse biogeographic zones, each with unique ecological features and a variety of flora and fauna. The major biogeographic zones of India include:

1. Trans-Himalayan Zone (THZ):
   • Geographic Area: Covers the cold desert regions of Ladakh, Lahaul-Spiti and parts of Jammu & Kashmir.It is located in the northernmost part of India.
   • Climate: Harsh, cold desert climate with low precipitation.
   • Major Flora: Sparse vegetation including alpine and desert plants.
   • Major Fauna: Snow leopards, Tibetan wild ass, Himalayan marmot.
2. Himalayan Zone (HZ):
   • Geographic Area: Encompasses the Himalayan mountain range including Himachal Pradesh, Uttarakhand, and parts of Jammu & Kashmir.
   • Climate: It includes diverse climates and habitats such as temperate forests, sub-alpine meadows, and alpine pastures. This makes this region a confluence of different bio-geographical zones, which leads to the richness in species diversity.
   • Major Flora: Oak, rhododendron, pine forests.
   • Major Fauna: Red panda, Himalayan tahr, various species of pheasants.
3. Northwestern Desert Zone (NWDZ):
   • Geographic Area: Covers the Thar Desert and parts of Rajasthan.
   • Climate: Arid and hot desert climate.
   • Major Flora: Cacti, thorny shrubs, desert grasses.
   • Major Fauna: Indian gazelle, Indian bustard, various species of desert lizards.
4. Semi-Arid Zone (SAZ):
   • Geographic Area: Includes areas like Gujarat, Madhya Pradesh, and parts of Maharashtra.
   • Climate: Semi-arid climate with moderate precipitation.
   • Major Flora: Acacia, thorny shrubs, dry deciduous forests.
   • Major Fauna: Chinkara, Indian fox, various species of migratory birds.
5. Western Ghats (WG):
   • Geographic Area: It is stretched along the western coast, covering states like Kerala, Karnataka, Maharashtra and Goa. The Western Ghats are a biodiversity hotspot renowned for their high levels of endemism and species diversity.
   • Climate: High rainfall and tropical climate.
   • Major Flora: Dense evergreen and deciduous forests, numerous endemic species.
   • Major Fauna: Malabar giant squirrel, lion-tailed macaque, various species of frogs.
6. Deccan Plateau (DP):
   • Geographic Area: The Deccan Plateau is a vast, elevated region characterized by diverse landscapes and habitats. It covers the central part of India including parts of Maharashtra, Telangana, and Madhya Pradesh.
   • Climate: The climate of this region is varied, from semi-arid to tropical.
   • Major Flora: Dry deciduous forests, scrubland, grasslands, and rocky plateaus.
   • Major Fauna: Indian gazelle, Indian wolf, various species of reptiles.
7. Gangetic Plain (GP):
   • Geographic Area: Encompasses fertile plains of Northern India formed by the Ganges River, covering states like Uttar Pradesh and Bihar. This zone is characterized by fertile alluvial soils and a network of rivers.
   • Climate: Tropical monsoon climate with high rainfall.
   • Major Flora: Alluvial forests, agricultural land.
   • Major Fauna: Ganges river dolphin, Indian rhinoceros, various species of migratory birds.
8. Central Highlands (CH):
   • Geographic Area: Covers parts of Madhya Pradesh, Chhattisgarh, and Jharkhand.
   • Climate: The climate of this region is varied, with hills and plateaus.
   • Major Flora: Dry deciduous forests, mixed forests.
   • Major Fauna: Bengal tiger, Indian elephant, various species of primates.
9. North East (NE):
   • Geographic Area: Includes northeastern states like Assam, Arunachal Pradesh, and Meghalaya.
   • Climate: It is characterised by high rainfall, tropical climate.
   • Major Flora: Evergreen forests, bamboo groves.
   • Major Fauna: Red panda, clouded leopard, various species of orchids.
10. Islands (IS):
    • Geographic Area: Includes the Andaman and Nicobar Islands and Lakshadweep. This zone has unique marine and island ecosystems.
    • Climate: Tropical maritime climate.
    • Major Flora: Coastal vegetation, mangroves.
    • Major Fauna: Nicobar pigeon, dugong, various species of coral reef fish.

• Climate: Climatics factors such as temperature, precipitation, and humidity influence the types of biogeography and the species that can thrive in a particular area.
  • For example, tropical regions with warm temperatures and high rainfall typically support greater biodiversity compared to polar regions with extreme cold.
• Geography and Topography: The physical features of a region, including its elevation, slope, and proximity to water bodies, affect biodiversity distribution. Mountain ranges, coastlines, and river valleys often support diverse ecosystems due to varied habitats and microclimates.
• Latitude: Latitude influences the biogeography and biodiversity by affecting factors such as temperature, seasonality, and sunlight intensity. Generally, areas closer to the equator exhibit higher species richness due to more stable and favorable climatic conditions than the areas distant from the equator(higher latitudes).
• Altitude: As altitude increases, temperature and atmospheric pressure decrease, leading to changes in habitat types and species composition. Mountainous regions often exhibit high biodiversity due to the variety of habitats and microclimates present along elevational gradients.
• Environmental Factors: Various environmental factors, such as soil composition, pH levels, nutrient availability, and water quality, affect the biogeography and the distribution of plant and animal species. Different species have specific environmental requirements and tolerances, influencing their spatial distribution.

• Diverse Topography: The varied topography of India, which includes mountain ranges, plateaus, plains, and coastal regions, creates a range of microclimates and habitats. Altitude variations, river valleys, and geological features shape the distribution of vegetation and biodiversity across different regions.
• Monsoon Climate: India's climate is predominantly influenced by the monsoon winds, which bring seasonal rainfall to different parts of the country. The interaction between the southwest and northeast monsoons results in distinct wet and dry seasons, influencing vegetation types and ecological patterns.
• Himalayan Barrier: The Himalayan mountain range acts as a barrier to the movement of weather systems, creating a rain shadow effect and influencing precipitation patterns in the northern and northeastern regions. This leads to the formation of diverse ecosystems, from alpine meadows to subtropical forests.
• Coastal Influence: India's long coastline, stretching over 7,500 kilometers, influences local climates and supports unique coastal ecosystems such as mangrove forests, estuaries, and coral reefs. Coastal regions experience specific weather patterns, tidal influences, and marine biodiversity.
• Soil Diversity: India's diverse geology has resulted in a wide range of soil types, including alluvial soils in river valleys, red and black soils in the Deccan Plateau, and laterite soils in coastal regions. Soil fertility and composition play a crucial role in determining vegetation types and agricultural practices.

• Habitat Loss and Fragmentation: Rapid urbanization, industrialization, and infrastructure development lead to the loss and fragmentation of natural habitats, disrupting ecosystems.
• Deforestation: Large-scale deforestation for agriculture, timber, and other developmental activities reduces forest cover, impacting flora and fauna.
• Climate Change: Changing climate patterns, including temperature variations and altered precipitation, affect the distribution and behavior of plant and animal species.
• Invasive Species: The introduction of invasive alien species disrupts native ecosystems by outcompeting or preying on local species, leading to imbalances.
• Human-Wildlife Conflict: As human settlements encroach upon natural habitats, conflicts between humans and wildlife increase, leading to negative impacts on both.

These zones are characterized by unique ecological features, including climate, topography, and soil composition, which influence the types of species that can thrive there. Biogeographic zones are crucial for biodiversity conservation efforts, as they provide insights into the ecological relationships between different species and their environments. It helps in identifying unique ecosystems, endemic species, and areas of ecological significance. The government, scientific institutions, and environmental organizations use this classification to guide policies and practices that aim to protect and sustain the rich biodiversity present in the country.