What Is the Biodiversity Crisis?
- The biodiversity crisis refers to the accelerated loss of species, habitats, and genetic diversity due to human activities.
- Unlike natural extinction events, which occur over millennia, today’s rates are extraordinary:
- Current extinction rate: 100–1,000 times higher than the natural background rate.
- At-risk species: Up to one million species are at risk of extinction in the coming decades.
How Do Scientists Measure Biodiversity Loss?
1. Biodiversity Metrics: Richness and Evenness
- Scientists measure biodiversity using two main metrics:
- Species richness: The total number of species in a given area.
- Species evenness: The distribution of individuals among those species.
- A coral reef with 500 fish species has high richness.
- If most fish belong to one species, evenness is low.
2. Long-Term Monitoring
- Long-term studies track changes in species populations and ecosystem health over time.
- Arctic fox populations are monitored annually to assess the impacts of climate change and competition with red foxes.
- Amphibian populations in tropical rainforests are tracked to understand the effects of habitat loss and disease.
Long-term monitoring allows scientists to identify patterns and potential causes of biodiversity loss, such as climate change, habitat destruction, and invasive species.
Evidence from Global Studies
The IPBES Report
- The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) synthesizes data from global studies.
- Key findings include:
- Wetlands: 85% lost since the 18th century.
- Coral reefs: Over 50% have been degraded since 1950.
- Pollinators: Declines threaten food security for 70% of major crops reliant on pollination.
The IUCN Red List
- The International Union for Conservation of Nature (IUCN) maintains the Red List, tracking species extinction risk.
- As of 2023:
- 41,000 species are threatened with extinction, including:
- 40% of amphibians.
- 41,000 species are threatened with extinction, including:
