The trend has had effects on air quality, petroleum consumption, and land use that are disproportionate to the population. Illinois still boasts an impressive range of habitat types. But habitat fragmentation and competition from exotic species have combined to render once-stable ecosystems less so. Complexity lingers mainly in habitats of only marginal use to humans, such as river bottomlands, swamps, hillsides and bogs. Humans have become so ecologically dominant in Illinois that it is impossible to draw clear lines separating natural systems from the social, economic, political, and technological systems that influence them.
Findings suggest that, overall, pollution is down, in many cases dramatically.
Rates of wetland loss have slowed, forests are coming back, and active citizen groups are at work restoring prairies and helping protect surviving natural areas. Economic and technological changes can have significant impact in curbing pollution. Greenhouse gas emissions peaked in 1970 but have declined since then as Illinois generated more of its electricity using nuclear power rather than fossil fuels. We don't know enough. Agencies of both state and federal governments generally collect specific kinds of data for specific pollution control and wildlife management purposes.