- Biodiversity Hotspots refer to biogeographic regions that are both a significant reservoir of biodiversity and are threatened with destruction.
- In other words, they are regions that are both rich in biodiversity and significantly threatened by human activities.
- These areas are critical for conservation efforts due to their high levels of endemic species, which are species found nowhere else on Earth.
- Biodiversity Hotspot as an idea was first developed by Norman Myers in 1988.
Criteria for Qualification as Biodiversity Hotspots
To qualify as a biodiversity hotspot, a region must fulfil the following two strict criteria:
- Endemism:
- It must have at least 1,500 vascular plants as endemics (> 0.5% of the world’s total) — i.e. it must have a high percentage of plant species found nowhere else on the planet
- A hotspot, in other words, is irreplaceable.
- Threat Level:
- It must have lost 70% or more of its original natural vegetation
- In other words, it must have only 30% or less of its original natural vegetation.
Biodiversity Hotspots in the World
- Currently, there are 36 biodiversity hotspots in the world.
- Most of them occur in tropical forests.
- They represent just 2.3% of Earth’s land surface.
- They contain around 50% of the world’s endemic plant species and 43% of all terrestrial vertebrates.
Biodiversity Hotspots in India
There are 4 biodiversity hotspots in India, as mentioned below.
- The Eastern Himalayas,
- Western Ghats & Sri Lanka,
- Indo-Burma, and
- Sundaland.
Eastern Himalayas
This region includes parts of Nepal, Bhutan, and northeastern India, harboring species like the red panda and the snow leopard.
Western Ghats & Sri Lanka
Stretching along the western coast, this region is known for its unique flora and fauna, including endangered species like the Nilgiri Tahr and Lion-tailed Macaque.
Indo-Burma
Extending across northeast India, Myanmar, and parts of Southeast Asia, it is rich in amphibians, birds, and reptiles.
Sundaland
Including the Nicobar Islands, this region is known for its marine biodiversity and unique terrestrial species.
Threats to Biological Diversity Hotspots
Despite their ecological significance, these hotspots of biodiversity face numerous threats, as described below:
- Habitat Destruction: Deforestation, urbanisation, and agricultural expansion lead to the loss of critical habitats.
- Climate Change: Altered temperature and precipitation patterns affect species distributions and ecosystem dynamics.
- Pollution: Industrial activities, pesticide use, and plastic waste severely impact biodiversity.
- Invasive Species: Non-native species can outcompete, prey on, or bring diseases to native species, disrupting the ecosystem balance.
- Overexploitation: Unsustainable hunting, fishing, and logging deplete species populations and degrade habitats.
Endemism
- There are more than 200000 species in India of which several are confined to India (endemic).
- Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere.
- A particular type of animal or plant may be endemic to a zone, a state or a country. The extreme opposite of endemism is cosmopolitan distribution.
Biodiversity of India
- India is recognized as one of the mega-diverse countries, rich in biodiversity and associated traditional knowledge.
- India has 23.39% of its geographical area under forest and tree cover.
- With just 2.4% of the land area, India accounts for nearly 7% of the recorded species even while supporting almost 18% of the human population.
- In terms of species richness, India ranks seventh in mammals, ninth in birds and fifth in reptiles.
- In terms of endemism of vertebrate groups, India’s position is tenth in birds with 69 species, fifth in reptiles with 156 species and seventh in amphibians with 110 species.
- India’s share of crops is 44% as compared to the world average of 11%.
India Represents
- Two ‘Realms’
- Five Biomes
- Ten Bio-geographic Zones
- Twenty-five Bio-geographic provinces
Realms
- Biogeographic realms are large spatial regions within which ecosystems share a broadly similar biota.
- A realm is a continent or sub-continent-sized area with unifying features of geography and fauna & flora.
The Indian region is composed of two realms. They are:
- The Himalayan region represented by the Palearctic Realm and
- The Malayan Realm represents the rest of the sub-continent
In the world, Eight terrestrial biogeographic realms are typically recognized. They are
- Nearctic Realm
- Palaearctic Realm
- Africotropical Realm
- Indomalayan Realm
- Oceania Realm
- Australian Realm
- Antarctic Realm
- Neotropical Realm
Biomes of India
- The term biome means the main groups of plants and animals living in areas of certain climate patterns.
- It includes the way in which animals, vegetation, and soil interact together. The plants and animals of that area have adapted to that environment.
The five biomes of India are:
- Tropical Humid Forests
- Tropical Dry or Deciduous Forests (including Monsoon Forests)
- Warm deserts and semi-deserts
- Coniferous forests and
- Alpine meadows.
Bio-geographic Zones
- Biogeography deals with the geographical distribution of plants and animals.
- Biogeographic zones were used as a basis for planning wildlife-protected areas in India.
There are 10 biogeographic zones that are distinguished clearly in India. They are as follows:
- Trans-Himalayas
- Himalayas
- Desert
- Semi-arid
- Western Ghats
- Deccan Peninsula
- Gangetic plain
- North-east India
- Islands
- Coasts
Bio-Geographic provinces
- A bio-geographic Province is an ecosystematic or biotic subdivision of realms.
- India is divided into 25 bio-geographic zones.
| Biogeographic Zones (10) | Biogeographic Provinces (25) |
| Trans Himalaya | 1A: Himalaya – Ladakh Mountains 1B: Himalaya – Tibetan Plateau 1C: Trans – Himalaya Sikkim |
| The Himalaya | 2A: Himalaya – North West Himalaya 2B: Himalaya – West Himalaya 2C: Himalaya – Central Himalaya 2D: Himalaya – East Himalaya |
| The Indian Desert | 3A: Desert – Thar 3B: Desert – Kutch |
| The Semi-Arid | 4A: Semi-Arid – Punjab Plains 4B: Semi-Arid – Gujarat Rajputana |
| The Western Ghats | 5A: Western Ghats – Malabar Plains 5B: Western Ghats – Western Ghats Mountains |
| The Deccan Peninsula | 6A: Deccan Peninsular – Central Highlands 6B: Deccan Peninsular – Chotta Nagpur 6C: Deccan Peninsular – Eastern Highlands 6D: Deccan Peninsular – Central Plateau 6E: Deccan Peninsular – Deccan South |
| The Gangetic Plains | 7A: Gangetic Plain – Upper Gangetic Plains 7B: Gangetic Plain – Lower Gangetic Plains |
| The Coasts | 8A: Coasts – West Coast 8B: Coasts – East Coast 8C: Coasts – Lakshadweep |
| Northeast India | 9A: North-East – Brahmaputra Valley 9B: North-East – North-East Hills |
| Islands | 10A: Islands – Andaman 10B: Islands – Nicobars |
