Introduction

Environmental problems in the Lake Erie ecosystem function as early warning signals for the other Great Lakes. As the shallowest of the lakes, Lake Erie has the shortest water retention time (less than three years), but it also has the largest watershed relative to its size, the highest human population density, the most farm land, and the largest number of major cities. These factors converge to make Erie the Great Lake where ecological disruption often shows up first. If we can develop a detailed understanding of ecological disruption symptoms on Lake Erie, we can perhaps avoid similar problems on the other Great Lakes.

Rapid ecological changes are in fact occurring in the Lake Erie ecosystem, some as puzzling as they are troubling. Evidence now suggests that these changes involve complex and often poorly understood interactions between many factors related to the lake's chemical, physical and biological integrity. From what we know now about the suite of possible problems and their causes, achieving ecosystem integrity in Lake Erie and the other Great Lakes will require greater recognition of the need to address chemical, physical and biological integrity as parts of a unified whole.