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
4.1 Climate Change
4.1.1 1 degree temperature rise: 10% of land species face
extinction. Coral-reef bleaching more frequent.
Species-rich tropical mountains likely to lose many
4.1.2 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.
4.1.3 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.
4.2 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.
4.3.1 Nitrate and phosphate pollution in lakes and
4.3.2 Airborne pollution e.g. DDT
4.3.3 Ozone depletion by CFCs
4.3.4 Acidification of oceans
5 Local factors
5.2 Habitat Change
5.3 Recreational use
5.4 Large-scale agriculture
5.6 Mineral exploitation
6 Alien or exotic species
7 Eutrophication: the pollution of ecosystems with excessive nitrate and phosphate