The Two Main Criteria for Biodiversity Hotspots

To be recognized as a biodiversity hotspot, a region must meet two strict criteria:

1. High Level of Endemism:
   The area must contain at least 1,500 species of vascular plants that are found nowhere else on Earth. This means the region supports a significant number of endemic species—organisms unique to that specific location and not naturally found elsewhere1234567.

2. Significant Habitat Loss:
   The region must have lost at least 70% of its original native vegetation, making it highly threatened and in urgent need of conservation1234567.

Why Endemism Is the Primary Criterion

While biodiversity hotspots are rich in overall species diversity, the primary basis for their designation is endemism—the presence of species that are exclusive to a particular region. This focus is deliberate, as endemic species are irreplaceable; their extinction would mean their loss from the entire planet. The emphasis on endemic plants (at least 1,500 species) ensures that hotspots are not just areas of high diversity, but also areas with unique evolutionary heritage123467.

Other Factors Considered

• Species Diversity: While important, overall species diversity alone does not qualify a region as a hotspot unless it is paired with high endemism8.

• Area Covered: The size of the region is not a criterion; some hotspots are relatively small but extremely rich in unique species.

• Plant Species: The focus is specifically on endemic vascular plants, as plants form the foundation of ecosystems and support a wide range of animal life123467.

The Importance of Hotspots

Biodiversity hotspots cover only about 2.5% of the Earth’s land surface but support more than half of the world’s plant species as endemics and nearly 43% of terrestrial vertebrate species as endemics. This makes them top priorities for global conservation efforts267.

Conclusion: The Correct Answer

Hot spots of biodiversity are primarily designated on the basis of endemism.

Correct answer:
(1) Endemism