Ronald E. Reynolds

Impact of the Conservation Reserve Program on duck recruitment in the U.S. Prairie Pothole Region

The U.S. Department of Agriculture (USDA)s Conservation Reserve Program (CRP) resulted in the conversion of about 1.9 million ha of cropland to perennial grass cover in the Prairie Pothole Region of North Dakota, South Dakota, and northeastern Montana by 1992. Many wildlife managers believed this cover would provide benefits to wildlife, including upland nesting ducks. During 1992-1995, we evaluated success of 5 duck species nesting in CRP fields and nearby Waterfowl Production Areas (WPA) throughout the region. We examined relationships between daily survival rates (DSR) of duck nests in CRP cover and landscape-level habitat and population parameters. We computed DSR of duck nests in other major cover types in our study area from data collected during 1980-1984 (pre-CRP) and 1990-1994 (CRP) periods. We then applied recruitment models to estimate duck production in our study area during peak CRP years (1992-1997) and compared these results with those that simulated the scenario in which cropland was in place of CRP cover (i.e., the CRP had not occurred). DSR were higher in all habitats combined during the CRP period compared to the pre-CRP period. Regressions of DSR in CRP cover on 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 1992-1997 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 model estimated an additional 12.4 million recruits from our study area to the fall flight as a consequence of the CRP during 1992-1997. Our results document benefits to 5 duck species in the northern plains associated with a farm program that provided financial incentives to landowners for planting undisturbed grass cover as an alternative to annual crops.

Band reporting rates for mallards with reward bands of different dollar values

Adult male mallards (Anas platyrhynchos) were banded in summer 1987 with reward bands of different dollar values (0-

The Farm Bill and Duck Production in the Prairie Pothole Region: Increasing the Benefits

400) to determine the lowest dollar value that would yield a reporting rate approaching 1.0. During the 1987-88 and 1988-89 hunting seasons, rewards of between 50 and

Geographic variation in band reporting rates for mallards based on reward banding

100 were required to yield a reporting rate near 1.0. We estimated reporting rate of standard bands to be 0.32. Reward bands with 5 and

Spatial and Temporal Variation in Wet Area of Wetlands in the Prairie Pothole Region of North Dakota and South Dakota

10 values produced reporting rates that were 1.5-2.0 times as large as those of standard bands. We developed a linear-logistic model to predict reporting rate as a function of the dollar value of reward bands

Hunting and mallard survival, 1979-88

Abstract The Food Security Act of 1985 contained provisions that affected wildlife conservation nationwide. Two provisions that most benefited waterfowl populations in the Prairie Pothole Region (PPR) were the Conservation Reserve Program (CRP) and “Swampbuster” (wetland conservation). Permanent cover established under the CRP provides attractive nesting habitat for upland-nesting ducks that is more secure than other major habitats. Swampbuster has prevented drainage of wetlands vital to breeding duck pairs. In 2007 many CRP contracts will expire. Deliberations will begin in late 2006 regarding the next Farm Bill. The United States Department of Agriculture needs sound biological information and scientific analyses to help establish wildlife priorities in the Farm Bill. We used data from breeding duck population and wetland habitat surveys to develop models for 5 species of upland-nesting ducks and applied these models to >2.6 million wetlands in a digital database for the PPR in North and South Dakota, USA. We used geographic information systems techniques to identify locations in the PPR where CRP cover would be accessible to the greatest number of nesting hens. We then summarized distribution of current CRP contracts relative to distribution of upland-breeding ducks. We also used our models to predict change in the breeding duck population (landscape carrying capacity) that might occur if certain wetlands were exempt from the Swampbuster provision. Our analyses showed that 75% of CRP contracts as of July 2005 were in areas accessible to high or medium numbers of breeding ducks and 25% were in areas of low populations. We suggest a method to prioritize CRP extensions and reenrollment of current contracts or target new contracts to maintain or increase duck production. Additionally, our models suggested that if the Swampbuster provision were removed from future Farm Bills and protected wetland were drained, this area of the PPR could experience a 37% decline in the waterfowl populations we studied.

USE OF WETLANDS BY SPRING-MIGRANT SHOREBIRDS IN AGRICULTURAL LANDSCAPES OF NORTH DAKOTA'S DRIFT PRAIRIE

We conducted a reward band study on mallards (Anas platyrhynchos) to estimate and test hypotheses about sources of variation in band reporting rate. We banded 25,398 mallards with standard and

Spring-summer survival rates of yearling versus adult mallard females

100 reward bands (3 mallards banded with standard bands for every reward-banded mallard) during preseason (Jul-Sep), 1988. We used a series of multinomial models to model the resulting 2,776 band recoveries from 1988 to 1991. Estimates of reporting rate for males shot in 10 harvest areas ranged from 0.29 to 0.46 and averaged 0.38 (SE = 0.020). We found evidence (P < 0.01) of geographic variation in reporting rates, but not of smooth latitudinal or longitudinal gradients. There was evidence (P = 0.07) of lower reporting rates for females than males, especially in prairie Canada and the Central Flyway. Except for young males in the northern Atlantic Flyway, estimated harvest rates were lower than historical estimates, as expected from recent restrictive hunting regulations. Patterns of geographic and age-sex variation in harvest rates were similar to those obtained using historical band-recovery data.

PATTERNS OF VARIATION IN CLUTCH SIZES IN A GUILD OF TEMPERATE-NESTING DABBLING DUCKS

Because of their sensitivity to temperature and precipitation, wetlands in the Prairie Pothole Region (PPR) are predicted to undergo changes in number, wet area, and hydroperiod as a result of climate change. However, existing PPR wetland monitoring programs are insufficient to accurately describe broad-scale variation in hydrology that might obscure signals of climate change. We assessed spatial and temporal patterns in wet area of ~40,000 wetland basins sampled each May from 1988–2007 in the U.S. PPR. The percentage of basins containing water, the wet area of basins relative to a baseline, the coefficient of variation of wet area of basins, and correlations of wet area values with values from previous years all varied temporally, spatially, and among water regimes that characterized annual duration of surface inundation. High variability in wetness suggests that monitoring programs designed to detect changes in PPR wetlands due to climate change must be implemented over broad spatiotemporal scales and consider natural and anthropogenic factors that influence water levels to be able to distinguish directional change from natural variation. Ancillary information such as annual indices of water conditions can greatly enhance the value of wetland classification schemes such as that used in the National Wetlands Inventory.

An Assessment of Re-Directing Breeding Waterfowl Conservation Relative to Predictions of Climate Change

A recent pattern of changes in hunting regulations offered a unique opportunity to further investigate the relationship between hunting and survival rates of mallards (Anas platyrhynchos). Consequently, we used 2 approaches to study the effects of hunting on survival of mallards banded on the Canadian prairie and the northcentral United States. First we compared recovery and survival rates during 1979-84, when regulations were stable and relatively liberal, with rates during 1985-88, when regulations were restrictive. Recovery rates declined between the 2 periods, suggesting that harvest rates declined. Survival rates for all age-sex classes were greater during the second period. Second, we analyzed the additive and compensatory nature of hunting mortality, for the same data, using the ultrastructural model of Anderson et al. (1982), as extended by Barker et al. (1991)