3.5 Threats to Biodiversity

Notes

Species are being lost far faster than the natural background rate. The main human threats are remembered with HIPPCO.

• Habitat loss, fragmentation and degradation (the largest threat)
• Invasive species
• Pollution
• Population growth of humans (and consumption)
• Climate change
• Overexploitation (overhunting, overfishing, illegal wildlife trade)
• Habitat fragmentation splits habitat into small isolated patches, which limits movement and mating.
• Extinction is the permanent loss of a species. An endangered species is at risk of extinction across all or most of its range; threatened species are likely to become endangered.
• The Endangered Species Act (1973) in the US protects listed species and their habitat.
• Example: a highway that splits a forest limits the movement of animals and reduces genetic mixing.