"Surface waters." . . "Degradation." . . "Conservation." . . "Wildlife." . . "Nations." . . "Internal." . . "Functions." . . "Resources." . . "Biodiversity conservation United States." . . "Water Pollution and Control." . . "Biology." . . "Policies." . . "Soil conservation." . . "Food." . . "Nutrients." . . "United states government." . . "Ecosystems." . . . . "Losses." . . "Wetlands." . . "Aquatic biology." . . "Biodiversity conservation." . . "Habitats." . . "Banks(waterways)" . . "Wetlands Research Program (U.S.)" . . "Earth(planet)" . . "Endangered species." . . "Ecosystem management." . . "Fresh water." . . "Swamps." . . . . . . "Review of wetland status, general ecology, biodiversity, and management"@en . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "Interior, freshwater wetlands of the United States include potholes, marshes, swamps, bogs, fens, and riparian wetlands. These wetlands are diverse in form and function and have unique properties that make them different from both terrestrial and aquatic ecosystems. The biological complexity and ecological functions of wetlands make these ecosystems among the most valuable and productive on earth (Mitsch and Gosselink 1986:11). For example, wetlands are valued for functions such as surface-water storage, groundwater recharge, removal and transformation of nutrients, and soil stabilization (Greeson, Clark, and Clark 1979; Smith et al., In Preparation). Wetlands also provide habitat for fish and wildlife, including a third of the nation's threatened and endangered species (National Research Council (NRC) 1992a:265). Despite their ecological importance, wetlands have been lost and degraded at alarming rates. An estimated 53 percent of the original 89.4 million ha of wetlands in the lower 48 States were lost by the mid-1970s (Dahl 1990), and losses continued at approximately 117,000 ha per year from the mid-1970s to the mid-1980s (Dahl and Johnson 1991). The national policy has changed gradually over the past 20 years from 'encouraging the draining and filling of 'worthless swampland' to recognizing the many benefits provided by wetlands and considering them a valuable national resource' (Ratti and Kadlec 1992:1)."@en . . "Interior Wetlands of the United States. A Review of Wetland Status, General Ecology, Biodiversity, and Management"@en . . . . . . . . . . . . . . . . . . . . . . . . . "Interior wetlands of the United States : a review of wetland status, general ecology, biodiversity, and management" . "Interior wetlands of the United States : a review of wetland status, general ecology, biodiversity, and management"@en . . "United States. Army. Corps of Engineers." . . "Storage." . . "Environmental Laboratory (U.S.)" . . "U.S. Army Engineer Waterways Experiment Station." . . "Legislation." . . "Ecology." . . "Wetlands United States." . . "United States." . . "Ecosystem management United States." . . "Soil stabilization." . . "Ground water." . . "Transformations." . . "IDAHO UNIV MOSCOW Dept. of FISH AND WILDLIFE RESOURCES." . .