Definition
Biodiversity hotspot
A biogeographic region that has exceptionally high levels of species richness and endemism but is also under significant threat from human activity.
- Biodiversity is not evenly distributed across the planet, certain areas, known as biodiversity hotspots, contain an exceptionally high proportion of species, many of which are rare, endemic, and endangered.
- These regions are often characterized by high species richness and ecological significance, making them critical for global conservation efforts.
- Many of these hotspots are located in tropical biomes, where the conditions are ideal for supporting a diverse range of life forms.
- The tropics contain the greatest concentration of biodiversity because of their warm, humid, and stable climates that favor continuous biological activity and high rates of primary productivity.
- In contrast, polar and desert regions have harsh conditions with low productivity and therefore support fewer species.
Factors Influencing Uneven Biodiversity Distribution
- Climate Stability: Consistent temperature and rainfall promote species survival and speciation.
- Primary Productivity: Areas with high photosynthetic rates (like rainforests and coral reefs) sustain complex food webs.
- Habitat Complexity: Diverse microhabitats allow multiple species to occupy different ecological niches.
- Evolutionary Time: Regions undisturbed by ice ages or major extinctions have had longer periods for diversification.
- Isolation: Geographic isolation (e.g., islands or mountain ranges) promotes endemism and unique species evolution.
The Amazon Rainforest contains an estimated 10% of all known species on Earth, including thousands of endemic plants, insects, and birds.
Global Biodiversity Hotspots
- There are 36 officially recognized biodiversity hotspots worldwide (as defined by Conservation International).
- Together, they cover less than 3% of Earth’s land surface but hold over half of all plant species and about 40% of terrestrial vertebrates.
- Major global hotspots are:
- Madagascar and the Indian Ocean Islands: Over 90% of species are endemic; severe deforestation threatens forests.
- The Western Ghats and Sri Lanka: One of the most species-rich tropical forests in Asia; home to thousands of endemic amphibians and plants.
- The Indo-Burma Region: Includes Vietnam, Cambodia, Laos, and Myanmar; under pressure from agriculture and urban expansion.
- Mesoamerica: Spanning Central America and southern Mexico; houses unique rainforest ecosystems.
- The Caribbean Islands: High endemism but heavily affected by deforestation and hurricanes.
- The California Floristic Province: A temperate hotspot with numerous endemic plant species, now facing urban and agricultural expansion.
