Wetlands serve as a transitional environment between water bodies and dry land and represent a significant part of the Nation's natural resources. They contain economically important timber, fuel, and food sources; provide esthetic and recreational opportunities; and influence the quantity, quality, and ecological status of water bodies, which include rivers, aquifers, lakes, reservoirs, and estuaries. Wetlands owe their existence, in part, to precipitation, streams, lakes, ground water, and oceans and, in return, perform important functions that affect the quantity and quality of these water resources. Although wetlands are best known for their function as habitat for birds, fish, and other wildlife, their less well known hydrologic and water-quality functions provide such benefits as reducing the severity of flooding and erosion by modifying the flow of water or improving water quality by filtering out contaminants.
Public and scientific views of wetlands have changed greatly over time. Only a few decades ago, wetlands were generally considered to be of little or no value. Those who eliminated wetlands through draining or filling were thought of as performing a public service. The role of the wetlands as a breeding ground for disease (primarily malaria) and their inability to be exploited for agricultural production caused them to be viewed as an economic "bad" rather than as a public "good," as they are viewed today. Because of new scientific knowledge, as well as a change in values (as manifested in our Nation's environmental laws), efforts to eliminate wetlands are viewed in a negative light by many. In fact, government and private citizens are making investments in the preservation, remediation, or creation of wetlands.
Although we now understand some of the benefits of wetlands and government agencies have established programs to protect them, wetland-protection policies remain a controversial public issue. In keeping with its mission, the U.S. Geological Survey (USGS) has prepared this report with the intent of informing public officials, scientists, and the general public about wetlands. Our purpose is to increase and help improve the understanding of this valuable resource and to provide the scientific information base upon which wise decisions regarding the classification, use, modification, or restoration of wetlands can be made. The hydrologic, biological, and economic consequences of these decisions are substantial and often politically contentious. The USGS takes no position on these issues but hopes to make a positive contribution to the process whereby these decisions are made.
The USGS is an earth science information agency. It collects, manages, and disseminates data; conducts interpretive scientific studies and research; and publishes the results of these efforts in many forms. The work of the USGS is organized into four thematic areas-resources, hazards, environment, and information management. Wetlands are addressed in each of these areas. For example, some wetlands play an integral role in water-resource availability because they are major discharge areas for some aquifers. Some wetlands relate to the hazards theme through their role in the mitigation of floods. Wetlands are affected by environmental changes, such as changes in the source or distribution of water, and, in turn, cause changes in the environment, such as shifts in vegetation or in habitat for birds, fish, and other animals; studies of these changes tie into the environmental theme. And, finally, with respect to the information management theme, the process of classifying, monitoring, and understanding wetlands is dependent upon the hydrologic, geologic, and topographic data collected by the USGS.
The USGS has taken this opportunity to draw on the expertise of the many agencies and organizations that have missions directly or indirectly related to wetlands to provide a broad background for government officials, water-resource managers, and the general public. You will note that many of the chapters of this volume have authors from other agencies with key roles in research, classification, or management of wetlands. Production of this volume was a team effort, just as management of wetlands is a team effort. We thank our colleagues in the many other agencies that helped make this report possible. I would like to pay special tribute to the late Dr. Edward T. LaRoe of the National Biological Service, coauthor of the chapter on research. He was a leading wetland researcher and played a pivotal role in the evolution of all biological research in the U.S. Department of the Interior.
Though this volume merely touches on the many and varied aspects of wetlands, it provides a starting place for further study and a base upon which to begin to understand the values of wetlands to the Nation. We hope it is useful, and we welcome your comments on this volume, as well as on our other products.