Factors that threaten biodiversity
The WRI has identified factors which threaten biodiversity
- An unusually high rate of human population growth and natural resource consumption.
- Inequality in the ownership, management and flow of benefits which threaten the livelihoods of the worlds pooerest people.
- The concentration of agriculture, forestry and fishing on a narrowing spectrum of products.
- Economic systems developed bby governments and businesses that fail to value the environment and its resourses.
- Legal and institutional systems that promote unsustainible exploitation at the expense of more sustainible statergies.
- Lack of knowlege and understanding in the management and conservation of biodiversity.
(Note a strong synoptic link to Global Challange)
The Stern Review suggest that climate change will happen far to rapidly for species to adapt.
Phenological studies show that seasonal events such as flowering, egg laying and fruiting have been advancing by several days each decade.
Coral bleaching caused by rising tempertures has increased since the 1980's.
Impact of Temperature rises
1°c - 10% of land species face extinction. Coral reef bleaching will be more frequent. Species-rich tropical mountain habitats are likely to loose many species.
2°c - Between 15 and 40% of land species could face extinction. Coral reef bleaching increasing. Almost 5% of low tundra and 15% of coniferous forest could be lost.
3°c - Anything between 20 and 50% of species could face extinction. Massive losses in biodiversity expected in hotspots. Mangroves will flood removing natural flood protections. Coral reefs will be severly affected.
Case Study: The Arctic
Impacts of Global Warming on the Arctic
- Localised shifting of ecosystems in a poleward direction.Coniferous forest will expand into the tundra zone.
- The tundra, with rare arctic plants, will shrink as rising sea levels drown coastal areas.
- Increased forest fires and insect infestation are expected to ravage coniferous forests and reduce both biomass and biodiversity.
- Marine life will respond to warmer sea temperatures and reduce ice cover. Improved food supplied will mean bigger fish stocks and the appearance of new species.
- Fragile food webs could easily be damaged, leading to the loss of tundra mosses and lichens that provide the main food for animals such as the Caribou.
Deforestation & Pollution
The clearance of forest cover results in loss of biodiversity and resources for indigenous populations. Knock on effects on the food web and nutrient cycling. There are also wider environmental impatcs as the removal of forest cover leads to increased soil errosion and flooding.
Pollution takes many forms but most significantly in terms of reducing biodiversity are:
-The acidification of oceans and acid rain on land.
-Nitrate and phosphate pollution in lakes and costal waters
-Airborne pollution, for example from the use of DDT
-Ozone depletion by CFC's