Broad-Scale Relations between Conservation Reserve Program and Grassland Birds: Do Cover Type, Configuration and Contract Age Matter?

The Conservation Reserve Program (CRP) is a voluntary cropland set-aside program where environmentally- sensitive cropland is retired to a conservation practice. Grassland birds should benefit because most CRP is grass habitat and because amount of land in CRP is highest in agriculture-dominated areas of the United States where grassland habitat has been most impacted. We used the Breeding Bird Survey and Common Land Unit (CLU) data (spatially-explicit data of farm field boundaries and land cover) to identify relations between types and configurations of CRP and grassland bird abundance in 3 Midwestern states. All 13 species we studied were related to at least one aspect of CRP habitat - specific conservation practices (e.g., native vs. exotic grass), CRP habitat configuration, or habitat age. Treating all types of CRP as a single habitat type would have obscured bird-CRP relations. Based on our results, creating a mosaic of large and small set-aside patches could benefit both area-sensitive and edge-associated grassland birds. Additionally, northern bobwhite and other birds that use early successional grasslands would benefit from periodic disturbances. CRP, agri- environment schemes, and other government-sponsored set-aside programs may be most successful when administered as part of a targeted, regional conservation plan.