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Freshwater Ecoregions of North America: A Conservation Assessment

Freshwater Ecoregions of North America: A Conservation Assessment
Robin A. Abell (Editor)
Washington, D.C.: Island Press
Publication Date: 

paper, 319 p., $65

In North America, fresh water along with the life it supports is one of the most abundant and important natural resources. The United States is home to the most diverse population of freshwater mussels in the world, with nearly 300 species. The North American continent also possesses 77 percent of all of the species of crayfish and is second only to Asia in the total number of fish species. These numbers are impressive, but how is our fresh water and its associated biota doing? If one considers habitat fragmentation, introduced species, altered hydrology and land use changes, then one might argue that freshwater ecosystems are not doing very well. Between 1950 and 1995 more than 450 species of fish were introduced into the rivers and lakes of the United States. Seventy-five thousand large dams and 2.5 million small dams have restricted flows and fish migrations on rivers and streams. Only 2 percent of the 5.1 million kilometers of rivers and streams in the United States remain free-flowing and undeveloped. Expanding human populations and changing land uses are continuing to add chemicals and pollutants into our waterways.

Although statistics about species and lakes are interesting, they do not provide particularly useful information for conservation. Freshwater Ecoregions of North America, as a report based on 76 ecoregions in North America, deals with whole ecosystems rather than individual species and puts emphasis on specific regions of the continent where much of the biodiversity is housed. An abundance of maps clearly pinpoints locations for highest species richness, greatest concentration of endemic species, areas of least habitat fragmentation and much more. These regions are adapted from mapping done by the U.S. Forest Service, based on distributions of native fishes. With some modifications to include a wider range of species, this book directs attention to areas with the greatest remaining biodiversity. The authors have evaluated the ecological distinctiveness and identified the conservation status of each region as well as provided a threat assessment as to how likely these regions are to sustain their current species populations. During a time when finite resources are available for conservation work, this report focuses on the regions that would benefit the most from conservation funding and manpower. It is sobering to note those ecoregions labeled as critical, suggesting that they are perhaps too far gone to respond to conservation efforts. However, many others remain in good enough condition to provide opportunities for preserving the integrity of the continent's freshwater heritage.

The value in this publication is not only that it provides a wealth of previously unpublished information on freshwater biodiversity but it also clearly illustrates the serious need for immediate conservation action in saving remaining freshwater systems. It also provides priority activities to enhance biodiversity conservationm along with a list of conservation partners doing work in each region. Freshwater Ecoregions of North America provides important groundwork for fostering important new conservation efforts in North America.

— James Steffen, Ecologist, Chicago Botanic Garden.