Biodiversity Threats

Biodiversity Threats

1. Unsustainably high human population growth rate and natural resource consumption

2. Lack of knowledge and understanding in the management and conservation of biodiversity

3. The concentration of agriculture, forestry and fishing on a narrowing spectrum of products

4. Global factors

   • Climate Change
     • 1 degree temperature rise: 10% of land species face extinction. Coral-reef bleaching more frequent. Species-rich tropical mountains likely to lose many species
     • 2 degree temperature rise: Between 15% and 40% of land species face extinction, including 25-60% South African mammals and 15-25% Australian butterflies. Coral reefs bleached annually in many areas. Almosy 5% of the low tundra and 25% of coniferous forest could be lost.
     • 3 degree temperature rise: Anything between 20% and 50% of land species could face extinction. Massive losses in biodiversity expected in hotspots. Large areas of coastal wetlands will be lost as a result of rising sea levels. Mangroves will be flooded, removing a natural coastal defence. Coral reefs will die. Strong drying in the tropics could lead to destruction of rainforests.
   • Deforestation: clearance of forest cover results in loss of biodiversity and resources, with knock on effects on the food web and nutrient cycling. Removal of forest cover leads to increased soil erosion and flooding.
   • Pollution
     • Nitrate and phosphate pollution in lakes and coastal waters
     • Airborne pollution e.g. DDT
     • Ozone depletion by CFCs
     • Acidification of oceans

5. Local factors

   • Fire
   • Habitat Change
   • Recreational use
   • Large-scale agriculture
   • Overexploitation
   • Mineral exploitation

6. Alien or exotic species

7. Eutrophication: the pollution of ecosystems with excessive nitrate and phosphate