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Wetlands of the United States

Their Extent and Their Value To Waterfowl and Other Wildlife

Summary of Chapters


The problem of saving wetlands is to prevent marshes, swamps, open shallow waters, and seasonally flooded lands from being drained, flooded, or filled, hence losing their value as wildlife habitat. These types of aquatic environments, collectively identified in this report as wetlands, furnish essential habitat for all waterfowl, most species of fur animals, and many species of farm game, forest game, and warm-water fish. Coordinated advance planning by all resource interests is the keynote to solving the problem. As an aid in such planning, the Fish and Wildlife Service, with the cooperation of State game agencies, conducted a wetlands inventory with emphasis on present usefulness of the lands as waterfowl habitat.

A century of wetland exploitation has taught many lessons in the use and misuse of wetlands. The Swamp Land Acts of 1849, 1850, and 1860 paved the way for transferring nearly 65 million acres of wetlands in 15 States from Federal to State administration for the purpose of expediting their drainage. Nearly all these lands are now in private ownership, and their use by wildlife is usually only a minor consideration. Although evidences of wetland losses as revealed by previous inventories are not completely reliable because they represent different types of coverage, it appears that at least 45 million of the original 127 million acres of natural wetlands have been drained or otherwise destroyed. Agricultural drainage (102 million acres now in organized enterprises) and flood control are the forces primarily responsible, but other activities such as canal construction, drainage for mosquito control, industrial expansion, and highway building have greatly reduced the wildlife values of some wetlands, particularly along the coasts.

Wetland soils have physical and chemical properties that are derived from the environment in which the soils originate. Climate, landform, aud native vegetation largely govern the nature of this environment, hence also the nature of the soils and their potential uses. Most wetlands are underlain by organic soils known as peat and muck, or by recently deposited, water-carried alluvial soils. In general, alluvial soils have higher agricultural potentials than peat and muck. Many peat and muck soils have proved unproductive for agriculture after drainage; others are inherently fertile. In many areas, there appears to be a direct relation between potentially good agricultural wetlands and presently good waterfowl wetlands, suggesting that competition between agricultural and wildlife interests will become more intense in the years ahead.

The wetlands inventory reveals the location, classification, and evaluation of 74,439,300 acres of wetlands as waterfowl habitat. At least 90 percent of all wetlands of importance to waterfowl are included. From the standpoint of waterfowl value, the total acreage covered by the inventory is distributed as follows (in millions of acres): 8.9, high; 13.6, moderate; 24.0, low; and 27.9, negligible. Values are based on relative waterfowl use in the State where the wetlands are located. By wetland categories, the eight inland fresh types comprise 63,491,000 acres, the three inland saline types comprise 1,618,000 acres, the three coastal fresh types comprise 4,041,000 acres, and the six coastal saline types comprise 5,290,000 acres.

The 20 wetland types are ecological classifications designed to help recognize the relative importance to waterfowl of the many different kinds of wetlands found in the United States. Type designations are also helpful in determining values for other forms of wildlife. As waterfowl habitat, the 11 types comprising the various kinds of marshes and open waters with emergent nonwoody vegetation are far more valuable to waterfowl than the 5 types that are only waterlogged or seasonally flooded, or the 4 types characterized by tree and shrub growths. However, no wetland type is altogether useless to waterfowl. Although most of the acreage of certain types, such as bogs, wooded swamps, and salt flats, are presently used very little by waterfowl in most localities, the small acreages that are now receiving waterfowl use may be all-important locally, and the little-used areas may have good possibilities for improvement. Such improvement may be the only way of holding waterfowl in a region where good habitat is scarce.

Use of the inventory in waterfowl management ranges all the way from formulating overall habitat-management plans by flyways to selecting individual wetlands for improvement as part of a watershed plan, or as a private duck marsh. As originally envisioned, the inventory was to act as a blueprint to show State and Federal land-use agencies the location and relative importance of wetlands that should be preserved or improved for waterfowl as soil and water conservation programs are carried forward. If effectively used for this purpose, the inventory will have far-reaching effects on keeping waterfowl populations at a harvestable level.

Public waterfowl areas, both State and Federal, offer permanent habitat for ducks and geese -- habitat free from land-use changes and usually free from the damaging effects of severe droughts. A well-integrated system of public refuges and shooting areas throughout the country is essential if waterfowl are to be properly protected, distributed, and harvested. Public areas are needed for protection in the breeding and wintering regions and for a combination of protection and distribution of hunting opportunities in areas used during the migration period. The Fish and Wildife Service estimates that public wildlife agencies should eventually administer 12.5 million acres of habitat, of which 7.5 million acres would be federally owned and 5 million acres State owned. That objective is now about 40 percent realized. The future of waterfowl hunting as a major American sport, however, depends on continuing the productivity of privately owned wetlands, particularly the breeding areas in the North Central States, in Canada, and in Alaska.

Improving wetlands for waterfowl on both private and public lands must receive greater attention in future years. Millions of acres of low-value wetlands can be made more attractive to ducks and geese by relatively simple and often inexpensive water-control measures. Despite concerted efforts to preserve wetlands on private property, economic pressures in some regions will eventually result in the conversion of more good duck habitat to croplands or to industrial and housing-development sites. In such regions, those wetlands not in high demand for other uses will have to be developed to their full waterfowl potential in order to maintain the present distribution and abundance of ducks and geese.

Contributions to other wildlife are far more extensive than most people realize. The use of marshes and swamps by such species as the muskrat, beaver, mink, and raccoon is common knowledge, but it is less well known that many species of small game and big game utilize wetlands to satisfy seasonal requirements. Altogether, at least 50 fur and game species in the United States, exclusive of waterfowl, inhabit wetlands to secure food, water, or protective cover. Wooded swamps (Type 7), although generally low in waterfowl value, are used by more resident-game species than any other type of wetland. In fact, the 5 types most used by other wildlife (Types 7, 6, 1, 8, and 2, in that order) are fairly low in waterfowl value, since none of these 5 types is among the 10 types used most by waterfowl. When determining the feasibility of a wetland reclamation project, values of resident game and fur animals deserve at least equal ranking with waterfowl values.


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