In another example, let's assume all the dead hollow trees are removed from a forest ecosystem. The number of animals of this type would be reduced. Insect populations could increase because of fewer insect eating birds and trees and other plants could be negatively affected. The whole ecosystem is affected. The amount of suitable habitat for a species of wildlife will determine the number of animals that can survive in the area.
Human activity has the greatest impact on the amount and quality of wildlife habitat in Illinois.
Wildlife habitat can be destroyed or its quality diminished as a result of urban sprawl, agricultural practices, pollution, sedimentation, or habitat fragmentation. People can also have a positive impact on wildlife populations through improvement and protection of habitat or ecosystems. The planting of trees and shrubs, as well as wildlife food plots, in the appropriate locations is one way landowners can improve wildlife habitat. People can protect ponds, streams, rivers and wetlands from sedimentation by reducing soil erosion on lands surrounding these aquatic ecosystems. Nesting boxes placed in ecosystems that lack dead, hollow trees will enhance the habitat for cavity nesting animals.