Evaluation of Restored Wetlands in the Prairie Pothole Region of the United States
Study Area
The region-wide database and extensive survey will provide information on wetlands in United States portion of the PPR. This portion of the PPR (36% of the 777,000 km2 in North America) includes large areas of North Dakota (101,010 km2), South Dakota (69,930 km2), Minnesota (54,390km2), Iowa (31,080 km2), and Montana (21,450 km2)(Grue et al. 1986). The region-wide database will represent the entire population of wetlands (all wetland classes and physiographic regions) restored by state, federal, and private agencies. In contrast, the extensive survey will focus only on a sample of seasonal and semipermanent wetlands restored on CRP lands or similar grassland habitats in the Missouri Coteau, Prairie Coteau, and Glaciated Plain physiographic regions (Bluemle 1977). The most common morainal landforms in these physiographic regions are ground moraine in the Glaciated Plains and terminal and dead ice moraine in the Coteau's (Bluemle 1977) Wetland resources and natural communities associated with these physiographic regions have been described by Kantrud et al. (1989), and van der Valk (1989).
Climate of the region varies along a northwest-to-southeast gradient, with precipitation and temperature increasing toward the southeast (Visher 1966). Likewise, climatic and physiographic gradients have resulted in spatial and temporal differences in agricultural development and as a result, in wetland impacts including drainage. Wetland losses have been greater in Iowa and Minnesota than in the Dakota's and Montana. Further, agricultural practices typically change from small grains in the Dakota's to more agriculturally intensive row crops in Minnesota and Iowa. Wetlands will be randomly selected following completion of task 3 (See overview on page 3) and will be stratified to include sites in representative portions of the PPR's northwest-to-southeast gradient.
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