Impact of the conservation reserve program on duck recruitment in the US Prairie Pothole Region

The U.S. Department of Agriculture (USDA)'s Conservation Reserve Program (C RP) resulted in the conversion of about 1.9 million ba of cropland to peren nial grass cover in the Prairie Pothole Region of North Dakota, South Dakot a, and northeastern Montana by 1992. Many wildlife managers believed this c over would provide benefits to wildlife, including upland nesting ducks. Du ring 1992-1995, we evaluated success of 5 duck species nesting in CRP field s and nearby Waterfowl Production Areas (WPA) throughout the region. We exa mined relationships between daily survival rates (DSR) of duck nests in CRP cover and landscape-level habitat and population parameters. We Computed D SR of duck nests in other major cover types in our study area from data col lected during 1980-1984 (pre-CRP) and 1990-1994 (CRP) periods. We then appl ied recruitment models to estimate duck production in our study area during peak CRP years (1992-1997) and compared these results with those that simu lated the scenario in which cropland was in place of CRP cover (i.e,, the C RP had not occurred). DSR were higher in all habitats combined during the C RP period compared to the pre-CRP period. Regressions of DSR in CRP cover o n the percent of each study plot in perennial cover and geographic location were significant (P< 0.01) for 4 of 5 duck (Anas spp.) species. Estimated nest success and recruitment rates for the 5 species combined during 1992-1 997 were 46% and 30% higher, respectively, with CRP cover on the landscape compared to a scenario where we simulated cropland in place of CRP. Our mod el estimated an additional 12.4 million recruits front our study area to th e fall flight as a consequence of the CRP during 1992-1997. Our results doc ument benefits to 5 duck species in the northern plains associated with a f arm program that provided Financial incentives to landowners for planting u ndisturbed grass cover as an alternative to annual crops.