The Great Lakes: The Natural History of a Changing Region.

John Abbott is a professor of history at Laurentian University’s Algoma University College. He is the co-author of The Border at Sault Ste Marie and The History of Fort St. Joseph.

“Nothing in nature is static; everything is in perpetual motion.” With this aphorism Wayne Grady concludes his survey of the basin’s “foundation stones.” An understanding of this fundamental truth is critical in evaluating the significance of any alteration which might require a human readjustment, as well as a sense of realism and a modicum of humility in regard to the difference propaganda and policy might make. Geologists, better than any other single group, know how inexorable natural forces are. As Grady points out, over a mere 10,000 years isostatic rebound has elevated Hudson Bay 935 feet, and continues to lift the Lake Superior basin some 20.5 inches every century. Continental drift increases the distance between the North American and European continents by 1.25 inches every hundred years. The Great Lakes themselves assumed their contemporary configurations only about 4,000 years ago, about the same time as the Egyptian pharaohs were erecting the great pyramids, and there is every reason to believe that the lacustrine shapes we now recognize are not graven forever in stone.

The author has elected to study the ecological history of the basin in the context of its woodland communities: the Boreal, Great Lakes–St. Lawrence, and Corolinian forests. While the first community supports a small and nucleated human population, logging and mining have effected “drastic changes” in the nature of its flora and the distribution of fauna. Six of the eight ecoregions within the basin fall into the second community. Here removal of the pine occasioned a fundamental ecological shift by changing the accustomed order of forest succession. The third is small and exotic, compensating for its small size by the extent of diversity in species. “Life in the Margins” surveys ecosystems at the interstices between forests and lakes, in dune and wetland, for example. “Water World” will be the most significant chapter for many readers, with its observations on water levels, currents, temperatures, limnology, pollution, fish and fisheries, collapses, and partial recoveries. Closely connected is the following chapter on the invasion of exotic species. Finally, Grady reflects on the abuses of the past and expresses a hope that our contemporary willingness to associate the health of the basin with our own health and well-being will render its fish edible, its air breathable, and its water potable.