Human Impacts on Biodiversity

1. Habitat Change Land cleared for: Logging for lumber Agriculture Cities Logging for lumber

2. Overexploitation – using a resource faster than it can be replaced. Overfishing – eg. sharks, cod

Overhunting – eg. buffalo

Overuse of water – eg. using lake water to irrigate crops can shrink the lake and affect the organisms that live there.

3. Pollution Air pollution Carbon dioxide from cars, power plants, and factories is causing global warming. Melting ice caps affects seals and polar bears.

Burning fossil fuels also releases chemicals that cause acid rain and smog. Many organisms cannot survive in water or soil that is too acidic.

Water pollution Oil spills Fertilizer run-off causes eutrophication

4. Invasive Species – a species that is introduced to an area where it is not normally found. They outcompete native species because they have no natural predators or because they reproduce faster.

Example: zebra mussels came to the Great Lakes on boats from Europe, and reproduced rapidly. They feed on algae, and have reduced algae populations. They cling to boats and clog engines and pipes. Their sharp shells make beaches unpleasant.