Date of Award
Master of Science
Ecology and Evolutionary Biology
Bird use of 24 Iowa wetlands was surveyed in 1999 and 2000. Three age categories of wetlands were studied: natural, old restored, and young restored. Natural wetlands had greater total and breeding species richness than restored wetlands. Total and breeding species richness did not differ between old and young restored wetlands. Habitat variables varied between wetland categories, with natural marshes having a greater percentage of vegetated area and a greater number of dominant emergent plant species than restored wetlands. Old restored wetlands had a greater percentage of wet meadow than young restored wetlands, suggesting, that with time, wet meadow zones will develop on wetland restorations. While restored wetlands are providing breeding habitat for some species of birds, they are still not attracting as diverse a breeding community as natural wetlands. Management of restorations should focus on establishing a diverse vegetative community that would offer marsh birds suitable breeding habitat. Models were created relating species richness estimates and individual species occurrences to within-wetland and landscape variables. Wetland area, wetland category, and the depth of the emergent zone were the most important predictors of species richness estimates at the within-wetland level.;The percentage of emergent zone, the percentage of robust emergent vegetation, and the depth of the emergent zone were each associated with five species occurrences, whereas the number of dominant vegetation species, the percentage of wet meadow zone, and wetland category were associated with four species occurrences. At the landscape level, the number of marshes within 1500m of each site was associated with five species richness estimates and six species occurrences. The area of semi-permanent wetland within 1500m of each site predicted breeding and non-waterfowl breeding species richness and six species occurrences. This study indicates that local bird diversity is influenced by factors beyond those at the nest site. Restoration efforts should focus not only on the establishment of vegetation characteristics within each basin, but should also focus on restoration on tracts of land containing several wetland basins.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Rachel Elizabeth Dault
Dault, Rachel Elizabeth, "Long-term effects of wetland restoration on bird communities in the Prairie Pothole Region of northwestern Iowa" (2001). Retrospective Theses and Dissertations. 16900.