Megadiversity countries and biodiversity hotspots

Detail

1. Megadiverse countries — what they are

• Megadiverse countries are countries that hold a very large share of the world's plant and animal species within their borders.
• Most of them lie in the tropics (the belt between the Tropic of Cancer, 23.5°N, and the Tropic of Capricorn, 23.5°S).

• Why the tropics are so rich: strong sunlight and rain all year → plants grow fast all year (high primary productivity) → many niches (ways of living) for animals → many species.

• NCERT lists 12: Mexico, Colombia, Ecuador, Peru, Brazil, DR Congo, Madagascar, China, India, Malaysia, Indonesia, Australia.

• Conservation International's list (1998) has 17. It is based on Mittermeier et al. (1997). It adds 5 more: the Philippines, Papua New Guinea, South Africa, the USA and Venezuela.
• Together these 17 hold about 70% of all species on Earth.
• The Government of India says that India is one of the world's 17 megadiverse countries (2025) [2]. (NCERT: one of 12.)

Megadiverse countries by continent (17-country list)

Continent	Countries
Americas	USA, Mexico, Colombia, Ecuador, Peru, Venezuela, Brazil
Africa	DR Congo, Madagascar, South Africa
Asia	India, China, Malaysia, Indonesia, Philippines
Oceania	Australia, Papua New Guinea

• Trap: the USA and Australia are on the 17-country list even though most of their land lies outside the tropics. Their large size and wide range of climates give them many species.

2. India's share of world biodiversity

• 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) [2].
• Endemism (species found naturally in only one region and nowhere else) is high. About 28% of India's plants and more than 30% of its animals are endemic [2].
• In the mountains of the Eastern Himalaya and the Western Ghats, 32–40% of vascular plants (plants with tubes that carry water and food, such as ferns and flowering plants) are endemic. In the Western Ghats, more than 50% of reptile, amphibian and fish species are endemic [3].

3. Like-Minded Megadiverse Countries (LMMC)

• The LMMC is a bloc of species-rich countries that negotiate together under the CBD (Convention on Biological Diversity, the treaty signed at the 1992 Earth Summit in Rio de Janeiro).
• Cancun Declaration (Mexico, 2002): the group called for an international system to make sure that the benefits from using biodiversity are shared fairly and equally [9].
• This is access and benefit-sharing (ABS): a company that uses a country's plants, animals or traditional knowledge (for example, to make a medicine) must get permission first and share the profit.

• This demand later led to the Nagoya Protocol (2010).

• Early members included Brazil, China, India, Indonesia, Colombia, Mexico, Ecuador, Kenya, Peru, Congo and Madagascar [9].

• India took over the chair of the LMMC in February 2004 [6].
• The group was still active during the talks that produced the Kunming-Montreal Global Biodiversity Framework. It issued a declaration on 7 December 2022 at CBD COP15 [11].

4. Biodiversity hotspots — definition and who created them

• A biodiversity hotspot is a region that has a very large number of endemic species and is also under severe threat of losing them.
• 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 ("Biodiversity hotspots for conservation priorities") [10].

• (NCERT says IUCN identified the hotspots. This is a common mistake. The criteria come from Myers and Conservation International, not IUCN.)

• Both criteria must be met:

Criterion	Threshold	What it measures
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, i.e. 30% or less of the natural vegetation left [10]	How endangered the region is

• Why hotspots are defined by plants:
• Plants are the primary producers. They turn sunlight into food (primary productivity).
• All the animals in an ecosystem depend on this food.
• So if a region has many endemic plants, it usually has many endemic animals as well.

5. Hotspots — number and spread

• There are 36 hotspots today. The latest, the Forests of East Australia, was added in 2016.
• Together they cover only about 2.5% of the Earth's land surface. But they hold more than half of all endemic plant species in the world.
• Logic: a small area with many unique species that face serious danger → conservation money spent there saves the most species for each rupee spent.

6. Case studies

Madagascar hotspot

• Madagascar is an island in the Indian Ocean, off the south-east coast of Africa.
• About 85% of its plants and animals are found nowhere else. Lemurs are the best-known example.
• Why endemism is so high: the island broke away from the mainland millions of years ago → its species evolved in isolation → many unique species formed.
• Threat: forests are cleared for food, firewood and farmland.
• Forests are cut → habitat is lost → endemic species have nowhere else to go → species die out.

Hawaii

• Hawaii is a group of volcanic islands in the central Pacific Ocean.
• Threats:
• Introduced species (plants and animals brought in by humans from other places) compete with native species or eat them.
• Development (towns, tourism, farms) destroys habitat.

7. Biodiversity hotspots in India

• India has parts of four of the 36 hotspots: the Himalaya, Indo-Burma, the Western Ghats and Sri Lanka, and Sundaland [2].

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

• Spatial traps:
• Only the Nicobar Islands belong to Sundaland. The Andaman Islands do not.
• Indira Point (about 6°45′N), the southern tip of Great Nicobar, lies in the Sundaland hotspot.
• The Eastern Ghats are not a hotspot.

8. Western Ghats and Sri Lanka hotspot

• Location: the Western Ghats 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 joins the same hotspot because it shares the same kinds of species.

• Why it is so rich:

• The south-west monsoon winds from the Arabian Sea hit the Ghats and are pushed up.
• The rising air cools and drops very heavy rain on the western (windward) side.
• This rain supports wet evergreen forests, where many species live.

• The southern hills are cut off from each other, so species evolve separately → high endemism.

• Share of India's biodiversity: about 30% of India's biodiversity is found in the Western Ghats. This includes many endemic flowering plants, fishes, amphibians, reptiles, birds, mammals and invertebrates [4].

• Endemic examples:
• 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.

• Humboldtia decurrens: an endemic plant whose hollow stems house ants.

• UNESCO World Heritage Site (2012) [7][8]:

• It was listed as a natural site under criteria (ix) (ongoing ecological and biological processes) and (x) (habitats of threatened species) [7].
• It is a serial property (one site made up of many separate pieces): 39 component sites grouped into 7 sub-clusters, covering about 7,95,300 ha [8].
• The components include Tiger Reserves, National Parks, Wildlife Sanctuaries and Reserved Forests [7].

• All 39 components belong to one biogeographic province (one natural region with similar species). They are the scattered remains of what was once a single unbroken forest [8].

• Protection debate (verify current):

• Western Ghats Ecology Expert Panel (WGEEP) under Madhav Gadgil (2011): recommended strict protection over large parts of the range, using graded Ecologically Sensitive Areas (ESAs) (zones where mining, quarrying and some kinds of building are limited).
• High Level Working Group (HLWG) under K. Kasturirangan (2013): proposed a smaller ESA, based on the natural landscape [4].
• On 13 November 2013, the Environment Ministry issued directions under the Environment (Protection) Act, 1986, following the HLWG report [5].
• The final ESA notification is still contested by the states over development, mining and the rights of people living there.

Prelims Hooks

• Hotspot criteria: at least 1,500 endemic vascular plants AND at least 70% of original habitat lost. A region must meet both, not just one [10].
• The hotspot concept came from Norman Myers (1988). The criteria were set by Conservation International (Myers et al., 2000), not by IUCN.
• 36 hotspots in all. The 36th, the Forests of East Australia, was added in 2016. Together they cover about 2.5% of land and hold more than half of all endemic plants.
• India has 4 hotspots: Himalaya, Indo-Burma, Western Ghats and Sri Lanka, and Sundaland. Only the Nicobar Islands are in Sundaland; the Andamans are not [2].
• India is about 2.4% of world land but holds about 8% of flora and 7.5% of fauna [2].
• NCERT: 12 megadiverse countries. Conservation International (1998): 17, which together hold about 70% of species. The USA, South Africa, Venezuela, the Philippines and Papua New Guinea are the five added.
• LMMC: set up by the Cancun Declaration (2002). Its focus is access and benefit-sharing under the CBD [9]. India chaired the group from February 2004 [6].
• Western Ghats: UNESCO World Heritage Site in 2012; natural criteria (ix) and (x); 39 components in 7 sub-clusters [7][8].
• Pairs: Lemur → Madagascar. Nilgiri tahr, lion-tailed macaque, Humboldtia decurrens → Western Ghats. Introduced species → Hawaii.

Mains Points

• Why biodiversity clusters in some places (GS-I):
• Heat and rain all year in the tropics → high primary productivity → many species.
• Isolation by islands (Madagascar, Nicobar) and separate hill ranges (southern Western Ghats) → species evolve apart → high endemism.

• This explains why megadiverse countries and hotspots fall mostly between the two tropics.

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

• They cover only about 2.5% of land but hold more than half of all endemic plants. This makes the best use of scarce conservation money.

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

• Megadiversity and equity:

• Species-rich countries are mostly developing countries. Rich countries' companies often use their genetic resources.

• Through the LMMC (Cancun, 2002), India pushed for access and benefit-sharing [9]. This shaped the Nagoya Protocol (2010) and the LMMC's position at COP15 in 2022 [11].

• Western Ghats: conservation vs development (GS-III):

• Threats: mining, quarrying, plantations, hydro projects and roads break up the forest.
• Gadgil (2011): wide, graded protection. Kasturirangan (2013): a smaller ESA, followed by Ministry directions in 2013 [5].
• The lack of a final notification shows the conflict between protecting nature and states' development and livelihood needs.