CRS-69 



1. better comparative knowledge of different types of wetlands; 



2. better ability to measure and compare wetland values; 



3. better knowledge of the value of wetlands in optimum and sub- 

 optimum natural conditions; and 



4. improved understanding of the effect of wetland size on value. 



Our knowledge of some types of wetlands, especially in coastal areas of 

 the Southeast, is extensive, fostered by a rich and diverse research tradition. 

 On the other hand, knowledge about most inland wetlands is limited, and almost 

 no research has been conducted on some of the rarer forms of wetlands in the 

 arid West. The result is an unclear picture of the actual value of many types 

 of wetlands. The wetlands which have been studied the most, coastal wetlands 

 in the Southeast, generally have higher overall values, as measured by either 

 rates of biological productivity or ability to serve more of the functions 

 described earlier in this chapter. 



Very little research has been conducted which compares different types 

 of wetlands in terms of functions and values offered. Developing a national 

 wetlands policy is difficult when the resource is so diverse, and knowledge 

 of components is highly variable. Most wetlands do not perform all the 

 functions ascribed to wetlands, nor could they perform all of them simulta- 

 neously. For example, wetlands may be valuable for assimilating waste, but, 

 as a result of assimilating that waste, the soils or vegetation may become 

 contaminated. Better analyses of how functions interrelate are needed. 



Most wetlands have been studied as natural systems. Research on the 

 impact of introduced stresses on an unmodified ecosystem have received limited 

 attention. After an ecosystem is stressed, its ability to perform functions 

 is altered. Usually, the overall value is reduced. However, certain functions 

 may not be affected, or may be enhanced by stress. A large percentage of the 



