India’s Biodiversity Hotspots and Megadiverse Status

A biodiversity hotspot is a region that is very rich in life and also under heavy threat. Both things must be true at once. The world has 36 hotspots (Conservation International).

The two tests

• Rich: the region must have at least 1,500 endemic vascular plants. These plants grow there and nowhere else.
• Threatened: it must have lost at least 70% of its primary vegetation.
• A region that passes only one test is not a hotspot.

Think of it like a hospital’s emergency ward. The ward is not for every patient. It is for patients who are both valuable and in danger right now. Hotspots tell conservation groups where to spend scarce money first.

How small are they?

• All 36 hotspots together cover only about 2.5% of Earth’s land (Conservation International).
• Around 2 billion people live inside them.
• Some hotspots have lost as much as 95% of their natural plant cover.

Where did the idea come from?

The idea came from a British ecologist, Norman Myers. In 1988, he named 10 tropical forest hotspots (Wikipedia). A year later, in 1989, Conservation International (CI) took up the idea as its plan of work. The list then grew step by step.

A megadiverse country is one of a small group of countries that hold most of the world’s species. There are 17 megadiverse countries. India is one of them (UNEP-WCMC).

The two tests

• The country must have at least 5,000 endemic plants.
• It must also border the sea, so it has marine ecosystems too.
• The list of 17 was drawn up by Conservation International, the same group behind hotspots.

Who is on the list?

• Asia: India, China, Indonesia, Malaysia, the Philippines.
• The Americas: Brazil, Colombia, Ecuador, Peru, Venezuela, Mexico, the United States.
• Africa: the Democratic Republic of the Congo, Madagascar, South Africa.
• Oceania: Australia, Papua New Guinea.

Together these 17 hold at least two-thirds of the world’s non-fish vertebrates (Wikipedia). Vertebrates are animals with a backbone, such as birds, frogs and mammals.

Why is India on it?

India has only about 2.4% of the world’s land (PLoS ONE). But it packs in snow peaks, deserts, rainforests, mangroves and coral reefs. Each of these holds its own set of plants and animals. So a small area ends up with a huge range of life.

Here is the key point. Megadiverse describes a whole country. A hotspot describes a region, and a region often crosses borders. So you can never say “India has four megadiverse areas”. India is one megadiverse country that holds parts of four hotspots.

Open the NCERT Class 12 Biology chapter on biodiversity. You will find older numbers (NCERT). Each one was right when it was first written. The world’s lists have since grown.

• The 34 count comes from the 2005 update. Two more hotspots were added in 2011 and 2016.
• The 12 comes from an older list. Even a 2014 research paper still used it (PLoS ONE).
• NCERT names three Indian hotspots: the Western Ghats and Sri Lanka, Indo-Burma, and the Himalaya.
• The fourth, Sundaland, reaches India only through the tiny Nicobar Islands. That is why many books leave it out.
• NCERT also says India holds 8.1% of the world’s recorded species.

The Himalaya is the youngest and highest mountain chain on Earth. As you climb, you pass from warm valley forests to cold alpine meadows. Each band of height holds its own plants and animals.

• The hotspot covers northern Pakistan, Nepal, Bhutan, north-west and north-east India, and parts of south-west China.
• Its animals include the tiger, the Asian elephant, the red panda and the rare white-winged duck.

One hotspot became two

The Himalaya was once counted as part of a larger Indo-Burma hotspot. A fresh review in 2004 split them into two separate hotspots (Wikipedia). That is why the world count rose, and why North-east India now sits in both.

The Indo-Burma hotspot is mostly in South-East Asia. Its main countries are Myanmar, Thailand, Laos, Cambodia and Vietnam, plus parts of southern China (Wikipedia). India holds its western edge.

• In India, it covers the North-east south of the Brahmaputra. Think of the hills of Mizoram, Manipur and Nagaland.
• It also covers the Andaman Islands (ANET).
• More than 300 million people live in Indo-Burma. No other hotspot has more people.
• Six large mammal species have been discovered here since 1992.

So North-east India sits in two hotspots. Its high mountains belong to the Himalaya. Its southern hills belong to Indo-Burma.

The Western Ghats are a chain of hills about 1,600 km long. They run along India’s west coast. Together with Sri Lanka, they form one hotspot.

• They cover less than 6% of India’s land.
• But they hold more than 30% of India’s species of plants, fish, reptiles, amphibians, birds and mammals.
• Many animals live only here, like the lion-tailed macaque.
• In 2012, UNESCO listed 39 sites in seven groups of the Western Ghats as a World Heritage Site (Wikipedia).

Why so rich? The hills catch heavy monsoon rain from the Arabian Sea. They are also old and cut off from other wet forests. Over a long time, cut-off groups of plants and animals slowly became new species.

Sundaland is a hotspot in South-East Asia. It includes Borneo, Sumatra, Java, Bali and the Malay Peninsula (Wikipedia). India’s only part of it is the Nicobar Islands.

• Sundaland has about 25,000 kinds of vascular plants. About 60% of them are endemic.
• It has about 380 mammal species, including two kinds of orangutan.

Andamans and Nicobars are split

The Andaman and Nicobar Islands are one Union Territory. But they sit in two different hotspots (ANET).

• The Andaman Islands lie in the Indo-Burma hotspot.
• The Nicobar Islands form the north-western tip of Sundaland.