Biodiversity hotspots in India

Topic: Biodiversity and its Conservation · NCERT: Beyond NCERT

Meaning

A biodiversity hotspot in India is any part of India that lies inside one of the world's 36 biodiversity hotspots. A hotspot is a region with at least 1,500 endemic vascular plants that has also lost at least 70% of its original habitat [7]. India has parts of four of them: the Himalaya, Indo-Burma, the Western Ghats and Sri Lanka, and Sundaland [1].

These four areas hold most of India's unique species, and they are under heavy threat. So they are where conservation money and effort save the most species.

Explanation

What makes a region a hotspot

• Who gave the idea:
• Norman Myers, a British ecologist, proposed hotspots in 1988.
• Conservation International set the formal criteria in Myers et al., Nature, 2000 [7].

• The idea did not come from IUCN. NCERT wrongly credits IUCN.

• A region must meet both of these tests. Meeting only one is not enough.

Test	Threshold	What it shows
Irreplaceability	At least 1,500 endemic vascular plants (more than 0.5% of the world's total)	How unique the region is
Threat	At least 70% of the original habitat lost, so 30% or less of the natural vegetation is left [7]	How much danger the region is in

• Endemic means a species is found naturally in only one region and nowhere else.
• Vascular plants are plants with tubes that carry water and food, such as ferns and flowering plants.
• Why the test uses plants:
• Plants are the primary producers. They turn sunlight into food.
• All animals in an ecosystem depend on this food.
• So a region with many endemic plants usually has many endemic animals too.

Why India has so many unique species

• India has only about 2.4% of the world's land area. Yet it holds about 8% of the world's plants (flora) and 7.5% of its animals (fauna) [1].
• About 28% of India's plants and more than 30% of its animals are endemic [1].
• Why endemism is high in these areas:
• Heat and rain all year in the tropics:
  • Plants grow fast all year (high primary productivity).
  • This creates many niches (ways of living) for animals.
  • So many species can live there.

• Isolation:

  • Islands such as the Nicobars and separate hill ranges such as the southern Western Ghats cut groups of species off from each other.
  • Each group evolves on its own.
  • Over time this produces many unique species.

• In the mountains of the Eastern Himalaya and the Western Ghats, 32–40% of vascular plants are endemic [2].

How the Western Ghats became so rich

• Monsoon rain:
• The south-west monsoon winds from the Arabian Sea hit the Ghats and are pushed up.
• The rising air cools, and its water vapour turns into rain. Very heavy rain falls on the windward side (the side facing the wind), which here is the western side.

• This rain supports wet evergreen forests, where many species live.

• Isolated hills:

• The southern hills are cut off from each other.

• Species there evolve separately, so endemism is high.

• Result:

• About 30% of India's biodiversity is found in the Western Ghats [3].
• More than 50% of the reptile, amphibian and fish species here are endemic [2].

Why hotspots matter for conservation

• Small area, big share:
• All 36 hotspots together cover only about 2.5% of the Earth's land surface.

• Yet they hold more than half of all endemic plant species in the world.

• Logic: a small area with many unique species in serious danger means conservation money spent there saves the most species for each rupee spent.

• Weakness:
• The method counts only plants.
• It can miss areas rich in animals or marine life.
• It can also miss dry lands such as grasslands and deserts.

Where it occurs

Hotspot	Indian part	Extends to
Himalaya	The whole Indian Himalaya	Nepal, Bhutan and neighbouring countries
Indo-Burma	North-east India (east of the Brahmaputra)	Myanmar, Thailand and Indochina
Western Ghats and Sri Lanka	Western Ghats (Sahyadri)	Sri Lanka
Sundaland	Nicobar Islands only	Malay Peninsula and the islands of Indonesia

• Western Ghats — location:
• They run along the western edge of the Peninsular plateau, roughly parallel to the Arabian Sea coast.
• They stretch from the Tapi river in the north to Kanyakumari in the south.
• They pass through Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu.
• The highest peak is Anamudi (2,695 m) in the Anaimalai Hills of Kerala.

• Sri Lanka is part of the same hotspot because it shares the same kinds of species.

• Endemic species of the Western Ghats:

• Nilgiri tahr: a mountain goat of the Nilgiri and Anaimalai hills.
• Lion-tailed macaque: a monkey of the evergreen forests.
• Malabar civet: a small, very rare carnivore (meat-eating animal).

• Humboldtia decurrens: a plant whose hollow stems house ants.

• Western Ghats — UNESCO World Heritage Site (2012):

• It was listed as a natural site under criteria (ix) (ongoing ecological and biological processes) and (x) (habitats of threatened species) [5].
• It is a serial property (one site made of many separate pieces): 39 component sites in 7 sub-clusters, covering about 7,95,300 ha [6].

• The pieces include Tiger Reserves, National Parks, Wildlife Sanctuaries and Reserved Forests [5].

• Sundaland in India:

• Only the Nicobar Islands are part of it.

• Indira Point (about 6°45′N), the southern tip of Great Nicobar, lies inside this hotspot.

• Hotspots elsewhere in the world (for comparison):

• Madagascar, in the Indian Ocean: about 85% of its plants and animals are found nowhere else. Lemurs are the best-known example.
• Hawaii, in the Pacific Ocean: threatened by introduced species (species brought in by humans from other places) and by development.
• Forests of East Australia: the 36th hotspot, added in 2016.

Don't confuse with

• Megadiverse country: this is a whole country that holds a very large share of the world's species. India is one of them (NCERT lists 12 such countries; Conservation International lists 17) [1]. A hotspot is a region, often shared by several countries, and it must also be under threat.
• Andaman Islands vs Nicobar Islands: only the Nicobar Islands are in the Sundaland hotspot. The Andamans are not part of any hotspot listed for India.
• Eastern Ghats: they are not a hotspot. Only the Western Ghats (together with Sri Lanka) form one.
• UNESCO World Heritage Site: this is a listing by UNESCO, for example the Western Ghats in 2012 under criteria (ix) and (x) [5]. A hotspot is a conservation priority set by Conservation International's two criteria, not by UNESCO.

Prelims Hooks

• India has parts of 4 of the 36 hotspots: Himalaya, Indo-Burma, Western Ghats and Sri Lanka, and Sundaland [1].
• Hotspot criteria: at least 1,500 endemic vascular plants AND at least 70% of original habitat lost. Both must be met [7].
• The concept came from Norman Myers (1988). The criteria were set by Conservation International (Myers et al., 2000), not IUCN.
• Trap: Sundaland in India means the Nicobar Islands only. Indira Point lies inside it. The Andamans and the Eastern Ghats are not hotspots.
• The 36 hotspots cover about 2.5% of land but hold more than half of the world's endemic plants. The 36th, the Forests of East Australia, was added in 2016.
• Pairs: Nilgiri tahr, lion-tailed macaque, Malabar civet, Humboldtia decurrens → Western Ghats. Lemur → Madagascar.

Mains Points

• Why India's hotspots are where they are (GS-I):
• Tropical heat and heavy rain: the monsoon pushed up against the Western Ghats gives high plant growth all year.
• Isolation: the Nicobar Islands and the separate southern hill ranges let species evolve apart, which raises endemism.

• Result: India has only about 2.4% of the world's land but about 8% of its plants and 7.5% of its animals [1].

• Hotspots as a way to set priorities (GS-III):

• Strength: they cover only about 2.5% of land but hold more than half of all endemic plants, so scarce money saves the most species.

• Weakness: the method counts only plants. It can miss areas rich in animals or marine life, and dry lands such as grasslands and deserts.

• Western Ghats — protecting nature vs development (GS-III):

• Threats: mining, quarrying, plantations, hydro projects and roads break up the forest.
• Gadgil panel (WGEEP, 2011): asked for wide, graded protection through Ecologically Sensitive Areas (ESAs, zones where mining, quarrying and some building are limited).
• Kasturirangan group (HLWG, 2013): proposed a smaller ESA based on the natural landscape [3]. On 13 November 2013, the Environment Ministry issued directions under the Environment (Protection) Act, 1986 [4].
• The final ESA notification is still disputed by the states over development, mining and the rights of local people.

Related concepts

• Megadiverse countries
• Biodiversity hotspot
• Madagascar hotspot
• Western Ghats and Sri Lanka hotspot

Read more

• Megadiversity countries and biodiversity hotspots