University of Illinois Extension

Wildlife - Just One Piece of the Picture

Wildlife populations depend on their environment or habitat to receive the basic needs for survival. An ecosystem or habitat provides populations of wildlife with food, water, shelter and space. If all four of these basic needs are not available in a suitable arrangement, populations of wildlife can not exist.

All populations of living things are interrelated. When one population of animals, plants, or insects increase or decrease, other populations of living things are also affected. For example, when shrubs and brushy areas are removed from an ecosystem, the rabbit population will likely go down. The reduced rabbit population will lower predator populations that use rabbits as a food source.

In another example, let's assume all the dead hollow trees are removed from a forest ecosystem. Cavity nesting animals such as bluebirds, nuthatch, wrens, screech owls, squirrels and woodpeckers have very little, if any, shelter available. 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. There are many things people can do to improve habitat for wildlife.

There are a number of natural resource management agencies in Illinois that can help people enhance and protect wildlife habitat. Listed below are a few of the public agencies which can provide ecosystem management expertise to people in Illinois.

1. Illinois Department of Natural Resources (formerly Department of Conservation)

In addition to wildlife biologists, foresters and fisheries biologists, this agency has private lands biologists to assist landowners in setting management goals and developing plans that will enhance wildlife habitat.


  • Illinois Acres For Wildlife
  • Habitat Stamp and Waterfowl Stamp monies
  • Illinois Nature Preserve System

2. Natural Resource Conservation Service (formerly Soil Conservation Service)

This agency provides technical assistance to landowners in such areas as soil conservation, watershed management and establishing tree windbreaks.

3. University of Illinois Extension

This agency provides educational programs concerning the management of ecosystems, agricultural systems and urban environments.

There are also many private conservation organizations which work to understand, manage and protect our natural environment in Illinois.


To help students understand the interrelationships of animals with components of their natural ecosystem.


Paper, pencils, reference materials


Assign students to study groups of two or three members. Each group should select an animal they would like to learn more about. Using references from the classroom or library, each group should determine their animal's requirements for food, water, shelter and space. Groups can report to the rest of the class about their animal through a short written report and/or a poster which describes their animal's habitat.

Have students think about, or actually observe, human activity around their community that impacts (positively or negatively) wildlife populations. As a class or individually, make a list of these activities. What types of wildlife might be impacted? What part or component of the habitat is being impacted? Are the activities producing positive or negative impacts on wildlife populations?

Make a list of things that could be done in your community to improve or protect wildlife habitat. Present your ideas to your local government, natural resource conservation agency, or choose one that your class could do something about.

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