CRS-70 



Nation's wetlands are directly or indirectly stressed in a variety of ways. 

 Wetland stresses are difficult to forecast because they are part of larger 

 hydrologic systems. Actions that change hydrologic patterns in other parts 

 of the system can alter a wetland downstream. A common problem is the effects 

 of upstream activities that increase sediment loads on hydrology downstream. 

 Isolated inland wetlands, such as prairie potholes, seem more easily affected 

 by change, perhaps because of their small size and separation from a larger 

 hydrologic system. 



Finally, the size of a wetland seems to be an important factor in deter- 

 mining value. A few functions, such as habitat and heritage value, may not 

 be influenced by size, but smaller wetlands are generally less complex eco- 

 systems and may be less productive then their larger counterparts. In some 

 areas, small but undisturbed wetlands are of high value, while, ironically, 

 man's ability to alter them indirectly or directly is much greater. For 

 example, some of these small wetlands have extremely high value for waterfowl 

 along the flyways, but other values are limited. Policy debate on wetlands 

 would be assisted if the effect of size and scarcity on value of wetland areas 

 could be expressed. 



Growing knowledge about wetland functions has gradually been incorporated 

 into Federal wetlands programs. Incorporation takes many forms, but it usually 

 appears first as arguments in legal decisions, and then may appear in regula- 

 tion or law. A growing appreciation of wetlands, their threatened status and 

 unusual value has led to development of Federal regulatory programs, discussed 

 in Chapter III, which attempt to consider a broader set of wetland concerns. 

 The ability to manage wetlands resources in a rational manner should improve 

 if answers to the scientific questions introduced above are found. 



