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Lincoln, NE, United States

Jurzenski J.D.,Felsburg Holt and Ullevig | Jorgensen C.F.,Rainwater Basin Joint Venture | Bishop A.,U.S. Fish and Wildlife Service | Grosse R.,U.S. Fish and Wildlife Service | And 2 more authors.
Systematics and Biodiversity | Year: 2014

Conservation efforts leading to the recovery of the federally endangered American burying beetle (ABB), Nicrophorus americanus Olivier, have been challenging because of the unknown causes of its decline, difficulty in establishing habitat requirements, and unclear population distribution across the species range. Extant populations of this widespread generalist species occur in broadly separated regions of North America with varying habitat characteristics. A habitat suitability model for ABB in the Nebraska Sandhills was developed over the course of 3 years resulting in a final cross-validated spatial model. The succession of models from 2009 to 2011 indicated that most of the predictive variables stayed constant, but biased sampling and extrapolation areas affected classifier values differently. Variables associated with ABB occurrence were loamy sand, wetland and precipitation. Five variables, loam soil, agriculture, woodland, the average maximum temperature, and urban development, were associated with ABB absence. The 2011 cross-validated model produced an AUC value of 0.82 and provided areas designated as highly likely to support ABBs. By limiting the model extent to the Sandhills ecoregion and using threshold-dependent classifiers, the final habitat suitability model could be an important resource for wildlife managers engaged in the recovery of this habitat generalist. © 2014 The Trustees of the Natural History Museum, London. Source

Tidwell P.R.,Arkansas Tech University | Tidwell P.R.,Advanced Ecology Ltd. | Webb E.B.,Arkansas Tech University | Webb E.B.,U.S. Geological Survey | And 2 more authors.
Journal of Fish and Wildlife Management | Year: 2013

Waterfowl nutritional requirements and food availability at migration stopover habitats may differ from those at nesting or wintering areas. Although there is little information on factors that influence waterfowl diets and food selection during migration, we hypothesized that bird age and wetland density in the surrounding landscape would influence food selection. Thus, the objective of this study was to quantify mallard Anas platyrhynchos and blue-winged teal Anas discors diets during migration and evaluate effects of age and wetland density on waterfowl food selection. We collected 30 mallards and 29 blue-winged teal with food items present in esophagi from wetlands in south-central Nebraska during spring 2008 and 2009. Smartweed Polygonum spp. and barnyard grass Echinochloa spp. were the most common seeds found in both mallards and blue-winged teal, while Naididae and Chironomidae larvae were the most common invertebrates in mallard and blue-winged teal diets, respectively. Invertebrates were consumed by both species in greater proportion than available. Both mallards and blue-winged teal collected in wetland complexes selected some seeds over others, whereas birds in isolated wetlands foraged on foods in proportion to availability. After-hatch-year mallards also selected for some seeds over others, as compared with hatch-year birds, which foraged opportunistically on available foods. If after-hatch-year birds and birds in wetland complexes are able to be more selective in their diets relative to food availability at individual wetlands, they may be able to acquire and replenish lipids reserves more efficiently than hatch-year birds or birds in areas with lower wetland densities. Source

Uden D.R.,University of Nebraska - Lincoln | Allen C.R.,U.S. Geological Survey | Bishop A.A.,Rainwater Basin Joint Venture | Grosse R.,Rainwater Basin Joint Venture | And 4 more authors.
Ecosphere | Year: 2015

In the present period of rapid, worldwide change in climate and landuse (i.e., global change), successful biodiversity conservation warrants proactive management responses, especially for longdistance migratory species. However, the development and implementation of management strategies can be impeded by high levels of uncertainty and low levels of control over potentially impactful future events and their effects. Scenario planning and modeling are useful tools for expanding perspectives and informing decisions under these conditions. We coupled scenario planning and statistical modeling to explain and predict playa wetland inundation (i.e., presence/absence of water) and ponded area (i.e., extent of water) in the Rainwater Basin, an anthropogenically altered landscape that provides critical stopover habitat for migratory waterbirds. Inundation and ponded area models for total wetlands, those embedded in rowcrop fields, and those not embedded in rowcrop fields were trained and tested with wetland ponding data from 2004 and 2006-2009, and then used to make additional predictions under two alternative climate change scenarios for the year 2050, yielding a total of six predictive models and 18 prediction sets. Model performance ranged from moderate to good, with inundation models outperforming ponded area models, and models for non-rowcrop-embedded wetlands outperforming models for total wetlands and rowcrop-embedded wetlands. Model predictions indicate that if the temperature and precipitation changes assumed under our climate change scenarios occur, wetland stopover habitat availability in the Rainwater Basin could decrease in the future. The results of this and similar studies could be aggregated to increase knowledge about the potential spatial and temporal distributions of future stopover habitat along migration corridors, and to develop and prioritize multi-scale management actions aimed at mitigating the detrimental effects of global change on migratory waterbird populations. © 2015 Uden et al. Source

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