How Do Humans Change Ecosystems?

Humans change ecosystems by burning fossil fuels, cutting down trees in the rain forest, driving gasoline-powered vehicles and doing other things that affect the climate of a particular environment. In all ecosystems, living things interact with each other in their physical environments. Factors such as sunlight, precipitation, moisture and temperature also affect these interactions.

Driving gasoline-powered vehicles and burning fossil fuels are among several activities that produce greenhouse gases. These gases affect the amount of heat in the Earth's atmosphere. They also affect the reflectivity of the Earth's surface and the amount of sunlight that reaches Earth. All of these things contribute to global warming, which affects ecosystems in many ways.

In some ecosystems, temperature affects the mating and migration habits of some species. According to the Environmental Protection Agency, 28 migratory bird species are nesting earlier on the East Coast due to climate changes. Some butterfly species have also changed their migration habits due to the warming. Cutting down trees affects the rain forest ecosystem in several ways. With fewer trees to provide cover, more of the sun's energy reaches the rain forest floor. Too much sunlight causes the soil to dry out, making it difficult for plants to thrive. If plants die off, there is less food available to the herbivores in the ecosystem. Deforestation also reduces the amount of water vapor returned to the environment, affecting moisture levels in the rain forest.