National Wetlands Inventory

Status and Trends Introduction

The Fish and Wildlife Service monitors and reports changes in wetland acreage for the United States. The Emergency Wetlands Resources Act of 1986 directs the Service to map our Nation's wetlands and deep water habitats and produce information on their characteristics, extent, and status. These maps and wetland information are important tools to help government and the public with stewardship of our Nation's natural resources.

Remote sensing is used extensively to monitor wetland acreage changes. Color infrared photography and other imagery taken at different dates are compared and changes are recorded and subject to statistical analyses. As part of this effort, the Service tries to identify areas of the country where wetlands are being lost at an unusually fast rate. These "hot spots" of wetland loss are candidates for special studies to monitor land use changes over time and to help detect wetland policy or regulatory issues, changes in land use practices, or other natural or human induced phenomenon that may be promoting changes in wetland habitats. Geographic information system (GIS) technologies and analysis is considered the best tool to identify national or regional hot spots of wetland loss without reliance on more expensive remote sensing techniques or the subjectivity of field reconnaissance.

Return to Status and Trends page.