Breeding Bird Responses To Farmed Wetland Restorations In The Prairie Pothole Region Of Iowa
Ryan N. Harr, Department of Natural Resource Ecology and Management, Iowa State University, 124 Science II, Ames, IA 50011; (515) 294-5409; FAX (515) 294-7874; rnharr@iastate.edu
William L. Hohman, Department of Natural Resource Ecology and Management, Iowa State University, 124 Science II, Ames, IA 50011
The vast Prairie Pothole Region (PPR), extending from the parklands of Canada southward into the north central United States, was once dominated by pothole wetlands interspersed in a matrix of mixed and tallgrass prairies. Conversion of native habitats to agricultural purposes is pervasive throughout the PPR. Changes in land cover and land uses have had profound influences on waterfowl and other wildlife communities inhabiting the region. A suite of wetland restoration programs is available to private landowners in the United States to restore habitat on their lands through the U.S. Department of Agriculture's Conservation Reserve Program (CRP). The recently introduced Farmable Wetland Program (FWP) aims at restoring temporary and ephemeral wetland functions to small areas in agricultural fields too wet to farm. These restored areas potentially provide important habitat to breeding birds. To better understand the effect restoration characteristics have upon wildlife communities, I assessed breeding bird use of these restored wetland communities in north-central Iowa in 2003 and 2004. Initial predictions were increased species richness and abundance at sites with more extensive hydrologic and vegetative restoration efforts. I surveyed 48 restored wetlands and 12 drained basins still in agricultural production in both years. Thirty-seven species were observed during 2003; seven new species were observed in 2004. Preliminary analysis of 2003 data indicated a positive relationship between species richness and abundance with level of hydrologic restoration and restoration size. Twenty of the 60 study sites were searched for nests in 2004; as of 1 July, 238 active nests had been located representing 16 species. Apparent nest success as of 1 July was nearly 50% across all species; predation and flooding were the leading causes of nest failure. Our results suggest that these areas provide valuable breeding habitat for birds and that increased size and level of hydrologic restoration increase their value.