Review of \u3ci\u3e Freshwater Ecoregions of North America: A Conservation Assessment\u3c/i\u3e by Robin A. Abell, David M. Olson, Eric Dinerstein, Patrick T. Hurley, et al.

Defining ecogregions as relatively large areas of land or water that contain a geographically distinct assemblage of natural communities, this book documents the efforts of the World Wildlife Fund-United States to identify areas with aquatic habitats in the United States, Canada, and Mexico that support globally outstanding biological diversity. Public and private conservation groups can then focus their efforts on preserving the aquatic ecosystems of the most globally significant areas. The book opens with its authors\u27 discussion of their use of a biological distinctiveness index, focusing on fish, mussels, and crayfish species, to delineate the ecoregions of North America. Much of the information used to evaluate and rank ecoregions is based on expert opinion. Environmental threats and the conservation status of each ecoregion are then evaluated. Finally, ecoregions that are highest priorities for conservation because of their global significance are identified. Ecoregion-based conservation approaches are advocated in the last chapter, the authors arguing that evaluation within an ecoregion should focus on distinct habitats, large examples of intact habitat, keystone habitats, and large-scale ecological phenomena (such as animal migration). This ecoregion-level assessment, however, should be initiated first in those ecoregions that have been identified as globally outstanding

Prairie pothole marshes as traps for nitrogen and phosphorous in agricultural runoff

Water quality of drainage influents and the lone effluent at Eagle Lake marsh, Iowa, was studied for 4 years (1976-1979). Because of drought conditions, there was no effluent from the marsh in 1976, 1977, or 1978. In 1979, the marsh was effective at removing inorganic N, especially N03-N, from runoff water passing through. It had little impact on levels of inorganic-P, total-P, and Kjeldahl-N; it was a net exporter of soluble organic carbon

Perspectives on the Delta Waterfowl Research Station-Ducks Unlimited Canada Marsh Ecology Research Program

Present wetland management has been developed largely on a trial and error basis (Figure 1 ). The effects of many important environmental variables on wetland productivity 253 are not known, consequently management results have not been predictable with a high degree of accuracy (Weller 1981 ). Many marsh management techniques have been described; however, consistently successful marsh management requires a more comprehensive understanding of the structure and function of wetland systems. Although there have been numerous observational studies, major advances in our understanding will result from tightly controlled experimentation which permits the integration of simultaneous research efforts by a number of different scientific disciplines (Reichle 1975, Weller 1978). Because wetlands are temporally dynamic, this type of multi-disciplinary ecosystem analysis must also span a number of years to document the annual and long-term variability within the system. By better understanding the structure and function of wetlands, managers will be better able to design management techniques and strategies suited to their particular situation and therefore realize greater success in manipulating the productivity of these systems (Figure I)

Transformation and fate of nitrate and atrazine in freshwater wetlands

Agricultural chemical contamination of surface and groundwater is a special concern in the Midwest. Nutrient loads to surface waters in this region are among the highest in the country, and contamination of surface and groundwater occurs from a variety of pesticides. In addition to improved farming systems that incorporate Best Management Practices and reduced inputs of nutrients and pesticides, the creation of buffer strips and other off-field sinks for chemical contaminants near their origin offers great promise for minimizing surface and groundwater contamination. In the Corn Belt, one of the most promising off-field strategies for reducing contamination of surface and groundwater is the restoration of wetlands in agricultural watersheds, specifically as sinks for agricultural chemical contaminants