Avifauna use of reference and restored bottomland forest wetlands in Eastern Kentucky

Abstract

Bottomland hardwood forest restoration provides a challenge for ecological engineers, because of the long time periods required for trees to grow, and hydrologic complexities. We examined avifauna communities and habitat in restored bottomland forest of Eastern Kentucky, and compared them to a reference wetland. The restored wetlands have had over 25 years to mature. Over the past 25 years, vegetation has increased in density and complexity; however, most the restored sites did not have standing water commensurate with the reference site, and the trees and shrubs are still immature. Habitat variability between the 14 different wetlands did not strongly factor into avifauna species diversity. More species of birds used the larger restored wetlands (>1ha), compared to smaller basins (<0.3ha); however, size had no effect on Shannon Diversity. In restored sites, diversity increases were often due to the presence of non-wetland dependent species. Overlap between species found in the restored wetlands compared to the reference site has increased over time (currently 65–79% overlap); but is still not commensurate with the reference conditions, and in some cases, progress has slowed considerably. The reference wetland had greater diversity, and more wetland-dependent species than any restored wetland. Seasonal differences in diversity were less pronounced in the natural wetland compared to the more dramatic seasonal variability in the restored sites. Wetland dependent birds were more common across seasons, and stayed longer, in the natural wetland. Seasonal changes in migratory birds provided more detailed insight into potential problems with restored wetlands.