Forests have been destroyed for centuries Cleared for agriculture and farming. Building materials Fire wood Living space
In 1950, over 10% of Earth’s land was covered by rain forests. Currently only 6%, and decreasing.
Sustained yield A balance between net growth and harvest. Maximum sustained yield The level of consumption at which the population declines if exceeded.
Most plant and animal biodiversity on Earth. As a result of deforestation, animals’ habitats are also destroyed.
succession can take several hundred years to restore a climax community. The required time for succession to reach climax community takes longer when biodiversity is greater. Succession may not be possible if large stands are destroyed
Harvested for farms, orchards, and urban development. Two factors driving exploitation of deciduous forests The rich soil is excellent for farmland. Hardwood trees are great material for furniture, flooring, and fuel.
Have not been logged as extensively as other forest types But, the growing need for wood has led to increased harvesting Countries in need of money are selling large stretches of forests to domestic and foreign companies.
Steppes and Prairies Human agriculture ▪ Native grasses are replaced with species specialized for agriculture ▪ Native animals have been replaced by herds of grazing cattle and sheep. This greatly decreases biodiversity
People from all over the world are dependent on plants & animals in their environments.
We attempt to maintain these resources by balancing population recruitment and harvest. Recall: sustainable yield. Overharvesting can threaten the existence of populations.
Threatened: Threatened species are vulnerable to endangerment in the near future. Endangered: An endangered species is one which has been categorized as likely to become extinct. Extinct: Species or populations which no longer exists.