Threats to Local Biodiversity

A variety of factors put stress on the diverse life forms that inhabit the Chicago Wilderness. Perhaps the greatest threats to our natural heritage include poorly planned development, invasive species, land management challenges and pollution.

Climate Change

photo: Tennesee Valley Authority

Climate change, also called global warming, is an emerging threat to biodiversity. Although the Earth's climate changes naturally over long periods of time, global warming is now occurring rapidly, primarily because of the addition of excess carbon dioxide and other "greenhouse gases" to the atmosphere from human activities such as fossil fuel burning and deforestation. These greenhouse gases trap heat in the atmosphere that would normally be radiated into space, and the atmosphere slowly warms as a result.

The climate in the Chicago region is already warming, and scientists believe that additional warming is inevitable. Predicted regional effects of climate change include hotter summers and warmer winters, with longer, more frequent, and more severe heat waves, higher humidity, stronger storms, more droughts, and less snow. The waters of Lake Michigan, rivers and streams, smaller lakes and wetlands will also be warmer.

While some of these changes will benefit certain plants and animals, many native species will be harmed by climate-related changes that are occurring far more rapidly than plants and animals' ability to adapt. Changes in climate can affect the timing of events that are key to survival, such as the springtime emergence of caterpillars that birds depend on to feed their young. Increased heat and humidity favor the development of insect pests and diseases that attack plants and animals. It is also believed that many highly adaptable invasive plants and animals will out-compete less adaptable native species in the changing and stressful conditions that will result as the climate warms.

The ultimate results may be that some species will disappear from the Chicago Wilderness region, and some of the species found only in this region may face extinction.

Poorly Planned Urban Development

The rapid development of land for urban uses is the primary threat to the remaining unprotected natural lands of our region, and in some cases it is causing serious degradation of protected lands as well. Development affects natural communities in many ways. Urban development increases the amount of paved surfaces, which alters the natural flow of water across the landscape (because the water is not absorbed where it falls). This changes the structure of wetlands, streams and rivers, and reduces water quality by allowing more silt and chemical pollutants to reach our waters. The design of sprawling developments reduces air quality because it forces people to drive more than they might in well-planned communities. The more time we spend in our cars, the more air pollution we produce. Sprawling development also breaks natural areas into small fragments. This is a problem for animals such as grassland birds that can only breed successfully in large continuous habitats. Urban development can further threaten biodiversity by disturbing natural cycles. Many of our region's natural communities are adapted to periodic fires and they depend on fires to maintain the health of the ecosystem. As development encroaches and breaks natural areas into small parcels, people stop this natural cycle.

Invasive Species

Invasive, non-native species are a threat to almost every type of natural community in the Chicago Wilderness region. Invasive species are non-native ones that people have intentionally or accidentally introduced to our region. Most non-native species are not invasive, but those that are spread out in their new environment and virtually take over. They alter the balance of natural communities, crowding out native plants and animals that have lived together for thousands of years.

Invasive species can wipe out many native species and greatly reduce the biodiversity of the ecosystems they invade. Particularly problematic invaders in the Chicago region include buckthorn, Asian honeysuckle and garlic mustard, which are reducing the diversity and health of local forests and savannas. Plants such as leafy spurge, reed canary grass, and purple loosestrife have invaded local prairies and wetlands, while thumbnail-sized zebra mussels compete with native aquatic creatures for food and space in the region's waters.

Land Management Challenges

People have altered many of the natural areas in the Chicago Wilderness region, reducing their ability to support diverse plant and animal communities. These systems will only recover if people help restore them to health. Managing and restoring our natural resources can be an extremely challenging process, but one worth undertaking. Healthy natural areas increase air and water quality, reduce flooding, produce oxygen, and support an abundance of life.

Pollution

Pollution is particularly problematic for the waters of the Chicago Wilderness region. Storm water that runs off the roofs of buildings, paved surfaces, and chemically treated landscaping picks up pollutants along the way. Runoff from residences, lawns, businesses, construction sites, and industries carries sediment, nutrients, pesticides, metals, grease, oil bacteria, salts and debris to nearby streams. Runoff from agricultural areas carries similar pollutants but in different concentrations. "Point sources," where pollution flows from a single source, include municipal wastewater treatment plants and sewer overflows. People have managed to make dramatic reductions in these point sources of pollution during the past two decades. However, a major challenge for the future will be to reduce the impact of development-related runoff.

Learn what you can do to address these threats to biodiversity and our environment!

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