The Birds of Chichaqua Bottoms Greenbelt (Polk County, Iowa): Patterns of Habitat Use and Implications for Management

Despite the fact that many birds are believed to be declining as a result of habitat loss and elimination of historic disturbance regimes, few studies have explored how restoration and management of mixed grassland and woodland systems influence bird communities. In this study, we tested whether habitat size, habitat type, and use of prescribed fire as a management tool affected the species richness and composition of bird communities sampled from 22 restored grassland and woodland sites within Chichaqua Bottoms Greenbelt (Polk County, Iowa). In 2004-5 bird communities were sampled by walking transects within each site and recording the presence and abundance of bird species identified by sight or vocalization. A total of 198 bird species was recorded across all 22 transects, and observed species richness was higher in larger habitats and habitats with greater structural complexity. Although habitat type was correlated with significant variation in bird community structure, the use of fire as a management tool did not appear to significantly influence either species richness or community composition of birds. Xeric prairies supported the fewest bird species within the restored landscape, with mesic woodlands and woodland -prairie mosaics supporting the most species. Interestingly, the frequency of site occupancy by Northern Harrier and Henslow\u27s Sparrow was not a function of burn history, and only the Bobolink appeared to be marginally more common in recently burned sites. Thus, we suggest that land managers might benefit from envisioning restoration as a landscape-scale process rather than a sitescale process. Single, isolated restoration sites may never accumulate all bird species that reflect pre-disturbance avifauna. Rather, restoration of individual sites may re-establish meta-communities within a region, with bird species present at only a fraction of all possible sites from year to year