What Is Biodiversity?
Biodiversity encompasses the variety of all living organisms on Earth, including genetic diversity within species, the variety of species within ecosystems, and the diversity of ecosystems across landscapes. It is the foundation of ecosystem services that human civilization depends upon.
Earth is home to an estimated 8.7 million species, yet only about 1.2 million have been identified and described. This rich tapestry of life has evolved over 3.8 billion years.
Levels of Biodiversity
- Genetic Diversity: The variation in genes within a species. Greater genetic diversity allows populations to adapt to environmental changes and resist diseases.
- Species Diversity: The variety of different species in a given area. Tropical rainforests and coral reefs are among the most species-rich ecosystems.
- Ecosystem Diversity: The range of different habitats, biological communities, and ecological processes. This includes forests, wetlands, grasslands, deserts, and marine environments.
The Extinction Crisis
Sixth Mass Extinction
Current extinction rates are estimated to be 100 to 1,000 times higher than natural background rates. Unlike previous mass extinctions caused by natural catastrophes, this one is driven primarily by human activities.
| Group | Species Assessed | Threatened | Percentage |
|---|---|---|---|
| Mammals | 6,596 | 1,323 | 20% |
| Birds | 11,188 | 1,492 | 13% |
| Reptiles | 11,341 | 2,381 | 21% |
| Amphibians | 8,450 | 3,471 | 41% |
| Fishes | 26,840 | 4,316 | 16% |
| Plants | 58,497 | 24,914 | 43% |
Main Drivers of Biodiversity Loss
- Habitat Destruction: Conversion of natural habitats for agriculture, urbanization, and infrastructure is the leading cause, affecting 75% of the land surface.
- Overexploitation: Unsustainable harvesting of wildlife through hunting, fishing, and logging depletes populations faster than they can recover.
- Climate Change: Shifting temperatures and precipitation patterns force species to migrate, adapt, or face extinction.
- Pollution: Chemical contaminants, plastics, and nutrient runoff degrade habitats and poison organisms.
- Invasive Species: Non-native organisms introduced by human activities outcompete, prey upon, or bring diseases to native species.
Ecosystem Services at Risk
Biodiversity provides essential services that sustain human well-being:
- Provisioning: Food, fresh water, timber, fiber, and genetic resources
- Regulating: Climate regulation, flood control, disease regulation, water purification
- Supporting: Nutrient cycling, soil formation, primary production, pollination
- Cultural: Recreation, spiritual enrichment, cognitive development, aesthetic experiences
The economic value of ecosystem services is estimated at 125 to 140 trillion US dollars per year globally, exceeding global GDP.
Conservation Strategies
- Expanding and connecting protected areas (30x30 target)
- Restoring degraded ecosystems
- Sustainable management of agriculture and fisheries
- Combating wildlife trafficking
- Integrating biodiversity into economic decision-making
- Supporting indigenous and local community stewardship