Avian response to harvesting switchgrass for biomass in southern Iowa
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The use of switchgrass (Panicum virgatum) as a biomass fuel would reduce dependency on fossil fuels in the Midwest and provide environmental benefits. Biomass switchgrass fields also provide habitat for grassland birds. This thesis evaluates bird use of switchgrass fields harvested for biomass in southern Iowa. Species responded differently to harvested and non-harvested portions of fields. Grasshopper sparrows (Ammodramus savannarum) preferred the shorter, sparser vegetation of harvested areas and sedge wrens (Cistothorus platensis) preferred non-harvested areas. In the Rathbun Lake Watershed in southern Iowa converting rowcrop fields in areas of marginal soil to biomass fields could increase the abundance of some species of management concern by greater than 20%. In the winter biomass fields with harvested and non-harvested areas provided foraging habitat (cut areas) and protective cover (uncut area) for birds that use the fields. In general, switchgrass fields provide habitat for grassland birds that are of management concern and could be a tool in grassland bird conservation if managed properly.