Patch-and landscape-scale effects on area sensitivity of grassland birds in Iowa
This study looks at the effects of patch and landscape characteristics on area-sensitivity of grassland bird species. We investigate the effect of area and perimeter-to-area ratio on grassland bird species found in the Iowa State Preserves, with a specific focus on area-sensitive bird species. We selected prairie preserves or preserves with a prairie component for inventory. Both area and perimeter-to-area ratio were good predictors for bird species found in the preserves. Perimeter-to-area ratio was a better predictor than area for area-sensitive grassland bird species. The other major aspect of my research addressed the possible effect of landscape factors on habitat use by area-sensitive grassland birds in southern Iowa. We selected six focal grassland bird species. Three of them responded to landscape variables. Dickcissel and Eastern Meadowlark responded to the amount of woodland in the landscape. Bobolink responded to amount of grassland in the landscape. Grasshopper Sparrow, Henslow's Sparrow and Bobolink did not respond to any of our landscape variables. Both of our studies showed that when managing for area-sensitive species it is important to take into account and, if possible, combine both patch scale and landscape scale variables.