Wetland Assessment Criteria 7 



gent, forested and scrub-shrub and marine intertidal) will usually 



warrant priority consideration for Federal and State acquisition. 



Documentable information (see definitions section) may be used to 



support giving priority to other wetland types. 

 All wetland types that are rare or have declined within an ecoregion 



may be considered. 

 An ecoregion sustaining a high or moderate Index of Loss (see 



definitions) could warrant priority consideration over an ecoregion 



having a low Index of Loss of wetlands present in 1954 at the start of 



the wetlands trends study. 



Statistically valid data or documentable information may be used to 

 support priority for a specified wetland type(s) within an ecoregion, a 

 State or portion of a State due to rarity or wetland losses prior to, 

 during or after the wetlands trend study, if NWI trends study data do 

 not accurately portray the wetlands trends or Index of Loss within a 

 State, portion of an ecoregion or other priority planning area. 



Wetland losses are continuing throughout the U.S. in spite of increased 

 Federal, State and local efforts to protect these areas. Of the estimated 

 original (i.e., at the time of European settlement) 215 million acres of 

 wetlands that existed in the conterminous U.S. (Roe and Ayres, 1954), less 

 than 95 million acres (44 percent) probably remain. For example, between 

 1954 and 1974, about 9 million acres of wetlands were lost (Frayer et al., 

 1983). Net annual wetland losses during this period averaged 458,000 

 acres (440,000 acres inland and 18,000 acres coastal). About 396,000 

 acres/year (87 percent) of this estimated annual wetland loss has been 

 attributed to agricultural conversion. Wetland losses were also due to 

 residential and commercial developments, ports and harbors, roads, 

 water development projects, erosion and inundation, mining for mineral 

 resources, livestock grazing and other land and water use activities. 



Destruction or degradation of wetlands eliminates or reduces some of 

 their values. Drainage of wetlands, for example, eliminates or reduces 

 many of the beneficial effects of the wetlands on water quality and may 

 directly contribute to flooding problems. When wetlands are converted to 

 another use, the general public loses benefits from the wetlands associated 

 with incremental flood, erosion and storm damage control, water quality 

 maintenance, outdoor recreation and fish and wildlife resources; the 

 public also inherits economic liability for correcting problems associated 

 with lost wetland functions. The broad public interest is served when 

 these wetland values are protected. 



Diking and draining wetlands for agricultural uses, such as pasture or 

 crop production, may significantly alter wetland functions and values but 

 not convert the wetlands to uplands or non-wetlands. For example, signi- 

 ficant wetland uses include muckland farming, row crops, hay, summer 

 vegetables, and blueberry and cranberry cultivation. Drainage and 

 pumping permits crop production during drier summer months but the 

 wetlands are maintained by saturation, inundation and/or flooding 



National Wetlands Priority Conservation Plan 



