Ch. 3— Wetland Values and the Importance of Wetlands to Man • 43 



carry an unknown risk of serious damage to hu- 

 mans and their civiHzation. Natural systems can 

 provide baseHne conditions that help determine the 

 extent to which the environment has been affected 

 by man's activities and pollution. They may pro- 

 vide models for restoring or replacing habitats that 

 have been significantly affected or even models of 

 long-term survival for redesigning gready modified, 

 man-dominated systems that typically have not 

 worked reliably over long periods of time. 



Many people believe that unaltered natural 

 areas, including wetlands, are valuable in and of 

 themselves, regardless of any tangible benefits or 

 ecological services society may receive from them. 

 The reassurance that wetlands and other types of 

 natural areas exist for both present and future gen- 

 erations can be a strong motivation to preserve 

 wedands in an undisturbed state. The Nature Con- 



servancy, an organization whose goal is "the pres- 

 ervation of natural diversity by protecting lands 

 containing the best examples of all components of 

 the natural world," has devoted 50 percent of its 

 past preservation efforts to the protection of wet- 

 lands. In the future, it plans to expand this to ap- 

 proximately 75 percent (53). Similarly, the North 

 Carolina Natural Heritage Program gives top pri- 

 ority to protection of Carolina bays (bog swamps), 

 bottom land swamps, and peat bogs (80). Under 

 the South Carolina Heritage Trust Program, 60 

 percent of the areas preserved are shallow impound- 

 ments, marshes, flood plains, and wetland depres- 

 sions (80). In the Wisconsin Scientific Areas Pro- 

 gram, which inventories unique natural areas, ap- 

 proximately 50 percent of all inventoried areas are 

 wetlands (36). 



ECOLOGICAL SERVICES OR RESOURCE 

 VALUES OF WETLANDS 



The interaction between the hydrologic regime 

 and the wetland topography, saturated soil, and 

 emergent vegetation largely controls the general 

 characteristics and the significance of the processes 

 that occur in wetlands. The processes are in turn 

 responsible for the ecological services the wetland 

 may perform (fig. 4). 



Isolated wetlands may temporarily store runoff, 

 and flood plain wetlands may provide additional 

 conveyance capacity for flood waters, thereby re- 

 ducing floodpeaks in downstream areas. During pe- 

 riods of inundation, water flows over and through 

 the wetland, depositing nutrient-rich organic and 

 inorganic material suspended in the water. This 

 suspended material is "trapped" along with any 

 toxic materials that may be bound onto this sus- 

 pended material. The nutrients and their substances 

 thus become involved in many complex biochemical 

 cycles within the wetland system. These nutrients 

 help fuel the relatively high plant productivity 

 characteristic of most wetlands during the growing 

 season. The leaves of plants provide food and hab- 

 itat for many forms of wildlife and endangered spe- 



cies during the growing season. At the end of the 

 growing season, when the vegetation dies back, 

 some of the leaf material remains in the wetland 

 to support future plant growth in the coming sea- 

 son. Other leaf material is flushed into adjacent 

 water bodies where it provides a nutrient-rich 

 source of food for many aquatic organisms in the 

 food chain. The plant roots anchor the wetland soils 

 and prevent their erosion in some flood plain and 

 coastal environiaents. The ecological services of 

 wetlands are described in more detail below.* 



Floodpeak Reduction 



The ability of wetlands to store and convey flood- 

 water is primarily a function of their topography. 

 Many isolated freshwater and river wetlands are 



^Recent reviews of the scientific literature have been completed by: 

 1) P. R. Adamus and L. T. Stockwell, "A Method tor Wetland Func- 

 tional Assessment," U.S. Department of Transportation, Federal 

 Highway Administration, Office of Research, Environmental Divi- 

 sion, Washington, D.C., 1983, p. 176; and 2) J. H. Sather and 

 R. P. Smith, "An Overview of Major Wetland Functions," U.S. Fish 

 and Wildlife Service, Washington, D.C.. 1983. 



