Wetlands, Status and Trends in the Conterminous United States, Mid-1970's to Mid-1980's

The U.S. Fish and Wildlife Service is the principal Federal agency with responsibility for protecting and managing the Nation’s fish and wildlife and their habitats. Because of the importance of wetlands to the Nation’s fish and wildlife, the Service is particularly concerned with the fate of wetlands and associated deepwater habitats. In 1982, the Fish and Wildlife Service’s National Wetlands Inventory completed a study of the status and trends of wetlands and deepwater habitats for the conterminous United States. The 1982 report estimated the acreage of wetlands remaining in the conterminous United States and the changes in wetland acreage between the mid-1950’s and the mid 1970’s.

The Emergency Wetlands Resources Act of 1986 requires the Fish and Wildlife Service to update the initial wetlands status and trends information every ten years, beginning with this report. This report is the first national update of the 1982 report and was prepared to fulfill the statutory requirements of the Act.

This report does not address the causes for changes in wetland acreage or the effects those changes may have had on the Nation’s fish and wildlife resources. A subsequent report is being prepared that will provide a more comprehensive analysis of the data presented in this report.

Wetlands, as measured by the status and trends study are defined by the Fish and Wildlife Service’s wetlands classification system Cowardin, et. al. 1979, that defines the biological extent of wetlands using various techniques including high altitude aerial photography It includes both vegetated and non-vegetated wetlands. References to this wetlands definition and terminology are found in Appendix A of this report.

This report uses one methodology (based on the Cowardin, et. al. classification system) for identifying and classifying wetlands. We recognize that other government reports may use different methodologies.