32 



8% Urban Development 



V 5% Other Development 



'^>yj: 



^i 'J^i'^ysyo/o Agriculture oi;)^;-r~^' 



0) 



3 



< 



o 



(0 



o 

 m 



0) 



o 



re 



•^ 

 o 



OT 



:\ r \/M > ' 



■ / \ ', / \ - 



PALUSTRINE WETLAND TYPES 



Fig. 29. Causes of recent wetland losses (mid-1950's to mid-1970's) in the conterminous U.S.; losses to agriculture are highlighted (from Frayer, 

 et al. 1983). 



and emergent wetlands, with losses of 5.8 and 2.7 million 

 acres, respectively. In addition, 0.4 million acres of 

 scrub-shrub wetlands were converted to agricultural use 

 between the mid-50's and the mid-70's. 



The most extensive wetland losses occurred in Louisi- 

 ana, Mississippi, Arkansas, North Carolina, North Dako- 

 ta, South Dakota, Nebraska, Florida and Texas. Greatest 

 losses of forested wetlands took place in the Lower Mis- 

 sissippi Valley with the conversion of bottomland hard- 

 wood forests to farmland. Shrub wetlands were hardest 

 hit in North Carolina where pocosin wetlands are being 

 converted to cropland or pine plantations or mined for 

 peat. Inland marsh drainage for agriculture was most 

 significant in the Prairie Pothole Region of the Dakotas 

 and Minnnesota, Nebraska's Sandhills and Rainwater 

 Basin and Florida's Everglades. Between the mid-50's 

 and mid-70's, estuarine wetland losses were heaviest in 

 the Gulf states, i.e., Louisiana, Florida and Texas. Most 

 of Louisiana's coastal marsh losses were attributed to 

 submergence by coastal waters. In other areas, urban 

 development was the major direct man-induced cause of 

 coastal wetland loss. Dredge and fill residential develop- 

 ment in coastal areas was most significant in Florida, 

 Texas, New Jersey, New York and California. 



Regional Historical Perspective 



While the national decline in wetlands is dramatic, 

 losses in particular regions and states are even more star- 

 tling. For example, California has lost over 90% of its 

 original wetland resource (U.S. Fish and Wildlife Service 

 1977). Less than 5% of Iowa's natural wetlands exist and 

 over 90% of the wetlands in Nebraska's Rainwater Basin 

 have been destroyed (Bishop 1981; Farrar 1982). Only 

 20% of the original bottomland hardwood forests in the 

 Lower Mississippi Alluvial Plain remain (McDonald, et 

 al. 1979). Other states with less than half of their original 

 wetlands or certain types include Michigan, Minnesota, 

 Louisiana, North Dakota, and Connecticut (Table 3). By 

 1955, Michigan had lost 8 million acres of wetlands 

 (Michigan Department of Natural Resources 1982). 

 Ohio, Indiana and Illinois probably have lost over half of 

 their wetlands, but supportive statewide data are not 

 available. In selected areas of Illinois, wetland losses 

 have been dramatic. For example, virtually all wetlands 

 have been eliminated in the East-Central Region, Big 

 Prairie Region and Green River Watershed, while 98% of 

 Illinois' southern bottomland swamps have been de- 

 stroyed (Illinois Department of Conservation 1983). 



