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Wetlands of the United States

Their Extent and Their Value To Waterfowl and Other Wildlife

Use of the Inventory

Drainage and other water-control projects affecting wetlands have a profound and frequently detrimental effect on both the quantity and the quality of these lands as waterfowl habitat. A few years ago it was impossible to estimate the net effects of such projects on waterfowl distribution and abundance, because there was not enough information. The present inventory makes it possible to know approximately how many acres of the different kinds of wetlands are used by waterfowl and to determine the relative value of these wet areas to ducks and geese in the individual States.


Federal and State agencies responsible for flood control, drainage, and related land-use adjustments can use the inventory to gain a perspective on the status of waterfowl habitat in areas where their projects are being planned. It is increasingly important that design for such projects should include facilities and measures needed to protect or enhance the remaining wetland habitat for wildlife.

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Providing waterfowl with the required amount of habitat does not require that every acre of wetland be retained in its original state. In their present condition, millions of acres of wetlands are of little or no importance to waterfowl. Many projects can be designed to accomplish their primary purposes and, at the same time, maintain, or even increase, waterfowl values. On the other hand, in some regions of the country (notably, the prairie pothole region of the North Central States) practically any amount of drainage of marshes or of temporary surface water deprives waterfowl of irreplaceable breeding habitat.

The Corps of Engineers, Department of the Army, regularly eliminates wetlands in connection with its responsibility for providing flood-protection works and major drainage facilities throughout the country. Congress, however, in the Coordination Act approved August 14, 1946, provided that the Corps of Engineers and other Federal water-control agencies should consult with the Fish and Wildlife Service and the States concerned to determine the effects of proposed projects on fish and wildlife resources, with a view to avoiding or mitigating any damaging effects on wildlife. The wetlands inventory data now available should help in the prevention of unnecessary drainage of choice wetlands habitat, although constant vigilance by construction agencies and conservation interests will be needed to achieve this end.

Equally important is a clearer recognition of the need for additional waterfowl habitat in areas where the inventory shows a dearth of wetlands attractive to ducks and geese. Obviously, the wetlands inventory provides only the first step in meeting such a need, but often the first step in planning water-control projects is the most important.

Broad land-use programs, such as those of the Agricultural Conservation Program Service (ACPS) of the U. S. Department of Agriculture, can also capitalize on the wetlands inventory. Through ACPS, the Federal Government provides cash assistance to farmers in order to encourage the adoption of soil- and water-conservation practices, including drainage, that might not otherwise be undertaken. In addition, Congress has provided for insured loans to farmers for drainage and other land-treatment measures. Such incentives should be curtailed when they encourage the drainage of wetlands that constitute essential waterfowl habitat.

The Soil Conservation Service provides the technical know-how for doing the work by planning on-the-ground conservation practices. Part of this vast soil-conservation program is a nationwide soil-classification survey that undertakes to show how different soils should best be used -- whether for intensive cropping, regulated pasture, forestry, or wildlife production. The wetlands inventory will show farm planners and administrators the location of wetlands of particular importance in the national waterfowl-conservation program. This knowledge can influence the choice of practices needed to preserve necessary wetlands habitat. At least, it will help to show where conflicting national interests occur and should lead to the establishment of policies that are more harmonious to all resource interests.

In the pothole area of the Dakotas and Minnesota, wildlife interests are hopeful that the tremendous value of potholes in duck production, as well as their value when managed as agricultural wetlands, will show the need for an agricultural policy that favors wetland preservation and opposes further drainage of surface waters.

Conservation of an adequate share of the wetland resource for wildlife will no doubt require more than the defensive action that has characterized most efforts so far. It will necessitate a forward-looking program aimed at establishing waterfowl and other wildlife habitat as permanent features of rural land-and-water-management programs.


The inventory has potential use in planning overall flyway-management programs. Flyways are now generally accepted as practical, semi-natural areas where effective management of migratory birds can be applied. Since 1948, they have served as the basis for administrative action by the Fish and Wildlife Service in setting the annual hunting regulations. Lincoln states:

The terms "flyway" and "migration route" have in the past been used more or less as synonyms but the modern concept of a flyway is that it is a vast geographic region with extensive breeding grounds and wintering grounds connected with each other by a more or less complicated system of migration routes. Each flyway has its own populations of birds, even of those species that may have a continental distribution. The breeding grounds of one or more flyways may (and usually do) overlap broadly, so that during the nesting season extensive areas may be occupied by birds of the same species but which belong to different flyways. [8]

Any plan for providing adequate habitat for large populations of waterfowl in a flyway must take into account both breeding and wintering habitat. Waterfowl are capable of migrating long distances without stopping, so providing habitat just for use during migration is not neeessarily essential to the welfare of the birds, though it is highly important from the standpoint of the hunter.

Unless the birds are induced to stop on their southern journey, hunting opportunities will be extremely limited in some States. It has been repeatedly observed that southbound waterfowl will take up at least temporary residence if attractive habitat is available enroute, and certain species will spend the entire winter in new, more northerly environments if food supplies and water conditions are favorable. For hunting, the inclusion of so-called intermediate wetlands is necessary to the adequate management of a flyway.

How can the wetlands data be utilized in the development of a flyway-management plan? There are two kinds of management in connection with waterfowl programs, although the two are closely interrelated. One concerns the birds alone, and the other concerns the habitat on which the birds depend. The first embraces regulations governing hunting and the actions necessary to control or abate depredation and disease. The present discussion is related primarily to the second kind of management, which concerns habitat used by waterfowl for breeding, migration, and wintering.

Wetland reports for individual States include county data forms that show, in most cases, whether a particular wetland type makes its most important contribution as breeding, wintering, or migration habitat. Each of these three kinds of habitat can be represented on flyway maps to show where wetlands should be preserved or created to take care of the seasonal requirements of waterfowl. For example, there is a direct relation between the distribution and abundance of shallow and deep inland fresh marshes (Types 3 and 4) and the distribution and abundance of young ducks produced in the United States.

The annual breeding-ground censuses show that about three-fourths of all the ducklings produced in the United States come from the Prairie Pothole States of North Dakota, South Dakota, Minnesota, and Montana. The wetlands inventory shows that 76 percent of the Type 3 and Type 4 marshes in the northern States are in the four Prairie States where 75 percent of the young are produced. This relation demonstrates the real importance of these two types for breeding waterfowl. Indirectly, it also points to the need for preserving all water areas in the pothole region in order that Types 3 and 4 may realize their full potential.

The location of State, Federal, and private waterfowl-management areas can be studied in relation to the present distribution and value of wetlands to determine those regions where additional management areas should be developed. Work of this kind, of course, will have to be carried out by both State and Federal wildlife technicians whose responsibilities tie in directly with waterfowl management.

Flyway Councils, composed of representatives from each State in a flyway, are logical organizations to undertake habitat-adequacy investigations on a flyway basis. The wetlands inventory furnishes the framework for the undertaking. Some of the councils have already initiated preliminary studies along these lines. The Fish and Wildlife Service encourages and will lend its full support to such studies.


The Fish and Wildlife Service, in cooperation with State game and fish agencies, is now (1956) engaged in a wetland-preservation program. The wetland inventory serves as its basis, furnishing essential facts for planning intelligent action. Encouraging results are beginning to take shape, and it is expected that this program will eventually show lasting wildlife benefits. A few examples of activities along this line follow.

In the Northeastern States, all wetlands rated high or moderate in importance to waterfowl are being examined to determine their vulnerability to drainage, filling, or other land-use changes. Many of the lower-value wetlands also will be studied in this regard. In areas where the reduction of wildlife values is threatened by imminent land-use changes, further studies are being made to see if the losses can be prevented. Where threatened wetland is of outstanding importance to waterfowl, consideration is given to acquisition of the tract by the State or Federal Government for development and management as a permanent waterfowl-management area. If this is not feasible, efforts are made to preserve the area for its existing natural values as a part of sound community planning -- recognizing water conservation, recreation, and wildlife as public assets. The growing awareness of these public values needs to be encouraged.

Field biologists of the Fish and Wildlife Service are stationed at strategic locations in North Dakota, South Dakota, and western Minnesota, where drainage of duck-producing marshes is a common agricultural practice. It is their job to try to preserve wetlands so they can be used by waterfowl, muskrats, pheasants, and other species. They are working with farmers, local planning and civic groups, and with State and Federal land-use agencies to find ways of preserving wetlands and developing an appreciation of wetland values.

In many cases, the biologists have found that farmers will retain their wetlands when they are shown that it can be profitable to do so. Fur farming, minnow raising, forage-crop production, and conservation of a water supply often are promising alternatives to drainage. Using surface water for irrigation is becoming more popular, and in some cases it can be done without materially reducing the value of the water areas for wildlife. Some farmers favor marsh development to attract more ducks, fur animals, and upland game, which enables them to rent attractive shooting and trapping sites.

The aim of the preservation program in the Dakotas and Minnesota is to create agricultural programs that will give more attention to waterfowl values in the future utilization of wetlands. This program is showing some encouraging results, but cash subsidies, extended credit, and engineering assistance for agricultural drainage are serious handicaps.

In the Southeast and Lower Mississippi Valley, the inventory is being used as an effective instrument for promoting an equal-partner relation with the U. S. Corps of Engineers in connection with future flood-control programs. This approach looks toward land-use planning that includes the retention and improvement of waterfowl habitat as one of the purposes of water-control planning. Programs in the Southwest and Far West are being developed with special attention to opportunities for wetlands development and management in connection with reclamation projects of the Bureau of Reclamation.

In the Northwest, biology-training schools for soil-conservation field workers are sponsored jointly by the Soil Conservation Service, the Fish and Wildlife Service, and State game and fish agencies. Schools such as these give agricultural fieldmen and administrators an opportunity to learn firsthand the various practices that are beneficial to wildlife in general and how these practices can be applied to lands and waters under their influence. The development and improvement of wetlands for wildlife is given special attention. These schools appear to be meeting with immediate success.


Community wetland projects throughout the nation can eventually pay big dividends in waterfowl management and in recreational development. Using the wetlands inventory as a guide, plans can be made for improving local marshes, ponds, and swamps which commonly are considered worthless.

To this end, the wetlands map of a county or watershed can be used to plan a waterfowl-management project in which local groups will take part. In addition to preservation of local habitat of high quality, the overall program can include such worthy projects as improvement of low-quality wetlands by impounding more water, by controlling weed plants, or by other means. Sportsmen's clubs, landowners, State and Federal wildlife biologists, agricultural and recreational planning groups, and possibly the Boy Scouts, 4-H clubs, and other youth groups, could be invited to participate in such projects, all contributing to the cause in proportion to their interest and resources.

In this connection, an encouraging forward step has been provided by an agreement developed subsequent to passage of the Watershed Protection and Flood Prevention Act of August 4, 1954 (Public Law 566, 83d Cong., 2d sess.). A Memorandum of Understanding between the Fish and Wildlife Service (Department of the Interior) and the Soil Conservation Service (Department of Agriculture) has been entered into for the purpose of encouraging the coordination and integration of fish and wildlife conservation with works of improvement carried out under this Act. In this cooperative program, it is agreed that the Fish and Wildlife Service and the State fish and game agencies may make such recommendations for fish and wildlife conservation as they deem practical during the planning stages of proposed projects. Approved measures for mitigating or preventing damages to fish and wildlife resources would become part of the watershed work plan. Inasmuch as drainage is one of the approved features of watershed management, the preservation of wetlands habitat will be a problem in some projects.

Since the adoption of acceptable measures for watershed work represents, and depends upon, the wishes of local people, wetland improvements for waterfowl will hinge largely on the information and attitudes of local interests. This fact points up the importance of education and teamwork on the part of State and Federal wildlife workers, sportsmen's clubs, and other organized groups interested in promoting wildlife conservation as a definite part of watershed-protection programs.

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