Refers to changes in the natural world due to the activities of people. Such changes may be positive or negative. For example, anthropogenic changes in soils can occur due to plowing, fertilizing, using the soil for construction, or long continued manure additions. When manure is added to soils, the change is considered beneficial, but when soils are compacted for use as parking lots, the change is considered negative. Other examples of anthropogenic effects on the environment include oil spills, acid rain, logging of old-growth forests, creation of wetlands, preservation of endangered species, among others.