Biodiversity is not evenly distributed across the Earth’s surface. While some regions have relatively low biodiversity, certain areas are extremely rich in species and unique ecosystems. These species-rich areas are known as “mega diversity zones” or “biodiversity hotspots.” Such areas contribute significantly to global biodiversity despite occupying a small portion of the Earth’s land surface.

• For example, although India accounts for only 2.4% of the world’s total land area, it contributes nearly 8% of the global species diversity. This is because of the presence of such biodiversity-rich pockets within the country.
• The concept of biodiversity hotspots was first introduced by Norman Myers, a British ecologist, in 1988. He proposed this idea to identify priority areas for in situ conservation—that is, conservation of species in their natural habitats. According to him, hotspots are the richest and also the most threatened reservoirs of biodiversity on the planet.

At present, there are 36 officially recognized biodiversity hotspots around the world. These are the Earth’s most biologically rich yet ecologically threatened regions. In order to qualify as a biodiversity hotspot, an area must meet two strict criteria:

1. It must contain at least 1,500 species of vascular plants that are found nowhere else in the world (known as endemic species).
2. It must have lost at least 70% of its original natural vegetation.

Many of these hotspots far exceed these criteria. For instance, the Sundaland hotspot in Southeast Asia and the Tropical Andes hotspot in South America each have approximately 15,000 endemic plant species. In some hotspots, the loss of native vegetation has reached alarming levels — up to 95%, highlighting the urgency of conservation efforts.