NORTH AMERICAN RIVERS

by Whit Gibbons

November 19, 2006

Need information about a major river that flows anywhere between southern Mexico and the Arctic, including all of Canada and the 48 continental states plus Alaska? If so, let me recommend the ideal reference source: "Rivers of North America" (2005, Academic Press) edited by Arthur C. Benke and Colbert E. Cushing. The book has more than 1,100 pages, with maps and color photographs.

Clearly a massive undertaking, the work consolidates facts about individual rivers, from geomorphology, hydrology, and water chemistry to biodiversity and ecology. Not surprisingly in an ecological book these days, emphasis is placed on human impacts, often with details of how pollution or modifications along a particular river have changed the natural river environment.

The book could be very useful for someone wanting raw data for a high school or college report about a particular river. An ecologist who needed general descriptions about a river where research had been conducted would also find the book a valuable resource. Another approach is to take a trip down memory creek, finding rivers that have some meaning in your life and learning something you didn't know about them. That's what I did.

A captivating photo of a swamp scene at an oxbow lake on the Pascagoula River reminded me of a field trip with Kurt Buhlmann and Mike Dorcas to capture two species of rare map turtles that inhabit the southern Mississippi river. From the book I learned that the river has 114 species of fish and a tributary, Black Creek, that is part of the National Wild and Scenic Rivers System.

A photo of the heavily vegetated, forest-covered banks of the broad expanse of the Tennessee River reminded me of another field trip. My son and I spent most of the night on the river searching for another species of map turtle, and I picked up a baby muskrat that showed us how fiercely it could bite. The book has information on the cultural history of rivers. For example, the Tennessee River valley was first inhabited more than 10,000 years ago, has evidence of agriculture 5,000 years ago, and the remains of temples built 500 to 1,200 years ago. Europeans did not even see the Tennessee River until DeSoto arrived in 1540.

A photo of the Flint River in Georgia brought back memories of searching for alligator snapping turtles, the largest freshwater turtles in North America. Although they were once common in the Flint, before their removal by turtle trappers in the mid- to late 1900s, I saw only one adult on a recent trip. The river is beautiful in spots, and according to some reports, alligator snappers are increasing in abundance. But the book indicates that the Flint has three endangered species of mollusks and almost a dozen nonnative fish species, including walking catfish and Asian swamp eels.

The southeastern rivers are dramatically different from the Rio Grande. I have an old photo I took of a sandstorm blowing across a treeless stretch on the Mexican side of the Rio Grande when I was working with an ecologist from Texas Tech who was studying lizards. From the book I now know that the river is the fifth longest in North America, and almost 20 percent of the more than 160 species of fish that inhabit the Rio Grande are rare or endangered.

The book's foreword was written by Robert F. Kennedy Jr. in his capacity as president of the Waterkeeper Alliance, an environmental organization focused on protecting rivers. As he says about the book, "you will find the few remaining pristine rivers that deserve conservation as benchmark systems." On the other hand, he notes that a reader will also find that some North American rivers "have major problems . . . for which radical and immediate CPR is required." The book indeed has details about the environmental good and bad for virtually all the continent's major rivers.

Art Benke and Bert Cushing have produced a monumental work that will serve as a basic comparative reference for many years. The book is also useful for people who want to reminisce about their favorite rivers.



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