"Do restored wetlands create suitable waterfowl habitat?"
Anderson, Scott H.
Summerville, Keith S.
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Historically, North American wetland ecosystems supported substantial waterfowl biodiversity prior to agricultural development. Loss of wetland habitats in agricultural states such as Iowa is often linked to regional declines in breeding waterfowl, and the restoration of open water wetlands is increasingly used to increase waterfowl habitat. While several studies have examined whether restored wetlands function as habitat for spring migrating waterfowl, data on fall habitat use is lacking. The goal of this study was to determine if restored wetlands functioned as suitable habitat for a diversity of waterfowl species. We hypothesized that natural wetlands would have greater species richness and abundance of waterfowl compared to restored wetlands. We also tested whether waterfowl community composition was a function of differences in environmental variables among wetland sites (hydroperiod, wetland age, percent cover and height of emergent vegetation). To test these hypotheses, we performed point counts of waterfowl populations in four restored and four natural wetlands in central Iowa. We observed 10 species of waterfowl using these wetlands, and we also detected a significant correlation between species occurrence and wetland habitat quality. Total abundance of waterfowl was marginally higher on natural wetlands compared to restored wetlands. Waterfowl habitat use also appeared to be a function of wetland hydroperiod and, perhaps the percent cover of vegetation surrounding any open water. Thus, our data suggest that the most critical factors to consider when managing a restored wetland for fall migrating waterfowl are to maintain consistent hydroperiods and increased cover of emergent vegetation.
Scott H. Anderson is a student at Drake University. Keith S. Summerville is an Assistant Professor in the Department of Environmental Science and Policy at Drake.