What is Biodiversity?

"Biodiversity" means biological diversity. It describes the variety of all the genes, species and natural communities that exist within a particular place.

Diversity of Species

photo: The Morton Arboretum

Healthy natural habitats generally have more biodiversity than damaged or degraded ones. For example, a healthy oak woodland would typically include tens or hundreds of plant species as well as habitat for hundreds or thousands of species of birds, mammals, reptiles, amphibians, insects, and other living things. A degraded oak woodland that has been damaged by overgrazing or fire suppression would have fewer varieties of plants and animals. It would have some of the same species, but in smaller numbers. It might still be an important natural community but the biodiversity of the degraded woodland would be lower than that of the healthy woodland. In even greater contrast, a soybean field that has soybeans and a few weed species, the occasional insect, and no nesting birds has exceptionally low biodiversity.

Diversity of Natural Communities

Within a region the size of the greater Chicago area, another way to measure biodiversity wealth is by the number and variety of natural communities that exist side by side. For example, the 14,000-acres in the Palos forest preserves in southern Cook County contain many types of natural habitats. The area contains oak and hickory groves, sloughs rich with fish and waterfowl, and open prairies filled with flowers. This variety of natural communities contributes greatly to the high level of biodiversity in the area. The value of Chicago Wilderness lies in the different kinds of natural communities the region protects--communities of plants and animals that are rare worldwide, and that depend on the Chicago region for continued survival.

Biodiversity in the Chicago Region: the Region's Diverse Natural Communities

photo: Ron Panzer, McHenry County Conservation District

The Chicago Wilderness contains a great diversity of natural communities, including various types of forests, savannas, prairies, wetlands and waters. Each type of community has its own unique set of living things, dependent on specific physical conditions. For example, prairies are grasslands that develop on flat lands where occasional fires shape the treeless landscape. The Chicago region's remaining prairies harbor colorful wildflowers, a great variety of grassland birds, and were once home to great herds of America Bison. Savannas are grasslands with some trees. Birds such as eastern bluebirds and red tailed hawks prefer to nest in the open savannas. Other creatures, such as gray squirrels and hairy woodpeckers are more at home in denser, shadier forests. Creatures such as beavers and great blue herons depend on wetlands for their survival. To find out where to go to see examples of the various types of natural communities, go to Things to See in the Explore Chicago Wilderness section of this Web site. To read detailed descriptions of the various types of communities, see the Chicago Wilderness Atlas of Biodiversity.

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