PREDICTING LESSER SCAUP WETLAND USE DURING SPRING MIGRATION IN EASTERN SOUTH DAKOTA

The relative influence of physical, chemical, and biotic wetland characteristics on wetland use by spring migrating lesser scaup (Aythya affinis [Eyton]; hereafter “scaup”) is not well understood. We compared characteristics of used and unused wetlands in eastern South Dakota. Used wetlands were larger (\u3e2 ha; P = 0.05), with higher amphipod densities (\u3e500 individuals m-2; P = 0.01) and higher chlorophyll-a concentrations (\u3e0.2; P \u3c 0.05). These wetlands had lower ionic conductivity (1.8 mS; P = 0.02), lower nitrates (1.0 ppm; P = 0.01), lower submerged aquatic vegetation density (P \u3c 0.01), and lower fine sediment proportions (≤150 μm grain size; P \u3c 0.01). Wetland use was best described by amphipod and submerged aquatic vegetation densities. The predictive model explained 50.4% of the variation in scaup use in a reserve dataset. Thresholds of tolerance by amphipods in relation to wetland habitats in the upper Midwest should be investigated further as indicators of a broader range of water and habitat quality characteristics for scaup

WETLAND HYDRODYNAMICS AND LONG-TERM USE OF SPRING MIGRATION AREAS BY LESSER SCAUP IN EASTERN SOUTH DAKOTA

Lesser scaup (Aythya affinis [Eyton]) populations remain below their long-term average despite improved habitat conditions along spring migration routes and at breeding grounds. Scaup are typically associated with large, semipermanent wetlands and exhibit regional preferences along migration routes. Identifying consistently used habitats for conservation and restoration is complicated by irregular wetland availability due to the dynamic climate. We modeled long-term wetland use by lesser scaup in eastern South Dakota based on surveys conducted during below-average (1987-1989) and above-average (1993-2002) water condition years. Wetland permanence, longitude, and physiographic region were all significant determinants of use (P \u3c 0.01). Long-term use was best described by a quadratic equation including wetland surface area variability, an index of wetland hydrodynamics that is linked to productivity, biodiversity, and value to waterfowl. Contrary to previous findings, our study shows that over the long term, lesser scaup are more than twice as likely to use permanent wetlands as they are semipermanent wetlands. The northern region of South Dakota\u27s Prairie Coteau, which holds the highest density of hydrologically dynamic permanent wetlands, should be considered an area of conservation concern for lesser scaup. The criteria we identified may be used to identify important lesser scaup habitats in other regions of the Prairie Pothole Region

Climate, Management and Habitat Associations of Avian Fauna in Restored Wetlands of California’s Central Valley, USA

The Wetlands Reserve Program (WRP) is one of several programs implemented by the United States Department of Agriculture to facilitate natural resource management on private lands. Since the WRP’s inception approximately 29,000 ha in California’s Central Valley (CCV) have been restored. However until now, actual benefits of the program to wildlife have never been evaluated. Hydrology in the CCV has been heavily modified and WRP wetlands are managed primarily to support wintering waterfowl. We surveyed over 60 WRP easements in 2008 and 2009 to quantify avian use and categorized bird species into 11 foraging guilds. We detected over 200 bird species in 2008 and 119 species in 2009, which is similar to or higher than numbers observed on other managed sites in the same area. We found that actively managed WRP wetlands support more waterfowl than sites under low or intermediate management, which is consistent with intended goals. Despite reported water shortages, greater upland and un-restored acreage in the southern CCV, WRP wetlands support large numbers of waterfowl and shorebirds, particularly in the early fall months. This is probably due to the severe lack of alternative habitat such as wildlife friendly crops at appropriate stages of the migration cycle. Improved access to water resources for hydrological management would greatly enhance waterfowl use in the southern CCV

Climate, Management and Habitat Associations of Avian Fauna in Restored Wetlands of California’s Central Valley, USA

The Wetlands Reserve Program (WRP) is one of several programs implemented by the United States Department of Agriculture to facilitate natural resource management on private lands. Since the WRP’s inception approximately 29,000 ha in California’s Central Valley (CCV) have been restored. However until now, actual benefits of the program to wildlife have never been evaluated. Hydrology in the CCV has been heavily modified and WRP wetlands are managed primarily to support wintering waterfowl. We surveyed over 60 WRP easements in 2008 and 2009 to quantify avian use and categorized bird species into 11 foraging guilds. We detected over 200 bird species in 2008 and 119 species in 2009, which is similar to or higher than numbers observed on other managed sites in the same area. We found that actively managed WRP wetlands support more waterfowl than sites under low or intermediate management, which is consistent with intended goals. Despite reported water shortages, greater upland and un-restored acreage in the southern CCV, WRP wetlands support large numbers of waterfowl and shorebirds, particularly in the early fall months. This is probably due to the severe lack of alternative habitat such as wildlife friendly crops at appropriate stages of the migration cycle. Improved access to water resources for hydrological management would greatly enhance waterfowl use in the southern CCV