Ecosystems in Illinois are deteriorating, their natural functions disrupted by fragmentation and stress. So concluded The Changing Illinois Environment: Critical Trends, a state-of-the-environment report published in 1994 by the Illinois Department of Energy and Natural Resources (now the Department of Natural Resources).

This first Critical Trends report recommended that the state begin collecting statewide data on both the extent and condition of its ecosystems in order to determine the most effective and economical natural resources policy.