Human-made structures, vegetation, and weather influence ferruginous hawk breeding performance

Studies of anthropogenic impacts on wildlife may produce inconclusive or biased results if they fail to account for natural sources of variation in breeding performance and do not use probabilistic sampling at a scale functional for management. We used stratified random sampling and generalized linear mixed models to test hypotheses on relationships of daily nest survival rate (DSR) and fledgling production with anthropogenic and environmental factors that influence reproduction in the ferruginous hawk (Buteo regalis). We conducted the study across ferruginous hawk range in Wyoming, USA, 2010–2012. We performed extensive field surveys of prey, vegetation, and nest substrates, and used spatially explicit data to quantify weather, and the most widespread forms of anthropogenic infrastructure (i.e., roads, oil and gas well pads) in ferruginous hawk territories. We found strong evidence that DSR and productivity were greater for nests on anthropogenic structures (i.e., artificial nest platforms, gas condensation tanks, abandoned windmill platforms, power poles) compared to natural substrates (i.e., trees, cliffs, rock outcrops). Additionally, ferruginous hawks produced more fledglings at territories with greater shrub cover and fewer severe storms during the June brood‐rearing period. Amount of oil and gas development and prey was not associated with either measure of breeding performance. Our results suggest that artificial nest platforms are an effective tool to improve breeding success of ferruginous hawks and nesting on anthropogenic structures does not constitute an ecological trap for this species. Although ferruginous hawks nested in some areas with very little vegetative cover, territories with greater amounts of shrub cover produced more fledglings. The negative impact of severe spring storms on fledgling production illustrates the importance of including future weather scenarios in management planning for this species because storms are predicted to increase in frequency and intensity as a result of climate change. Published 2015. This article is a U.S. Government work and is in the public domain in the USA

WallaceZacharyFishWildlifeHumanMadeStructures(SupplementalMaterialTableS1-S2).pdf

Studies of anthropogenic impacts on wildlife may produce inconclusive or biased results if they fail to account for natural sources of variation in breeding performance and do not use probabilistic sampling at a scale functional for management. We used stratified random sampling and generalized linear mixed models to test hypotheses on relationships of daily nest survival rate (DSR) and fledgling production with anthropogenic and environmental factors that influence reproduction in the ferruginous hawk (Buteo regalis). We conducted the study across ferruginous hawk range in Wyoming, USA, 2010–2012. We performed extensive field surveys of prey, vegetation, and nest substrates, and used spatially explicit data to quantify weather, and the most widespread forms of anthropogenic infrastructure (i.e., roads, oil and gas well pads) in ferruginous hawk territories. We found strong evidence that DSR and productivity were greater for nests on anthropogenic structures (i.e., artificial nest platforms, gas condensation tanks, abandoned windmill platforms, power poles) compared to natural substrates (i.e., trees, cliffs, rock outcrops). Additionally, ferruginous hawks produced more fledglings at territories with greater shrub cover and fewer severe storms during the June brood-rearing period. Amount of oil and gas development and prey was not associated with either measure of breeding performance. Our results suggest that artificial nest platforms are an effective tool to improve breeding success of ferruginous hawks and nesting on anthropogenic structures does not constitute an ecological trap for this species. Although ferruginous hawks nested in some areas with very little vegetative cover, territories with greater amounts of shrub cover produced more fledglings. The negative impact of severe spring storms on fledgling production illustrates the importance of including future weather scenarios in management planning for this species because storms are predicted to increase in frequency and intensity as a result of climate change.Keywords: oil and gas development, ferruginous hawk, Buteo regalis, anthropogenic infrastructure, artificial nest platform, prey abundance, nest survival, fledgling production, severe weather, WyomingKeywords: oil and gas development, ferruginous hawk, Buteo regalis, anthropogenic infrastructure, artificial nest platform, prey abundance, nest survival, fledgling production, severe weather, Wyomin

Variables considered for use as covariates of small mammal prey density in the shrub-steppe and grassland regions of Wyoming, 2010–2012.

<p>Variables considered for use as covariates of small mammal prey density in the shrub-steppe and grassland regions of Wyoming, 2010–2012.</p

Locations surveyed for small mammal prey species in three non-mountainous ecoregions of Wyoming, 2010–2012.

<p>Survey locations are shown as block dots, small black squares show the extent of the randomly selected townships in the study area. Inset shows location of Wyoming in the United States. See text for more details on sampling design.</p

Predicting above-ground density and distribution of small mammal prey species at large spatial scales

Datasets containing distances and covariate values for a study on small mammal density and remotely-sensed environmental covariates in shrub-steppe and grassland ecosystems in Wyoming, USA, 2010-2012

Developing priorities for metapopulation conservation at the landscape scale: Wolverines in the Western United States

Wildlife populations are often influenced by multiple political jurisdictions. This is particularly true for wide-ranging, low-density carnivores whose populations have often contracted and remain threatened, heightening the need for geographically coordinated priorities at the landscape scale. Yet even as modern policies facilitate species recoveries, gaps in knowledge of historical distributions, population capacities, and potential for genetic exchange inhibit development of population-level conservation priorities. Wolverines are an 8–18 kg terrestrial weasel (Mustelidae) that naturally exist at low densities (~5/1000 km2) in cold, often snow-covered areas. Wolverines were extirpated, or nearly so, from the contiguous United States by 1930. We used a resource selection function to (1) predict habitat suitable for survival, reproduction and dispersal of wolverines across the western US, (2) make a rough estimate of population capacity, and (3) develop conservation priorities at the metapopulation scale. Primary wolverine habitat (survival) existed in island-like fashion across the western US, and we estimated capacity to be 644 wolverines (95% CI = 506–1881). We estimated current population size to be approximately half of capacity. Areas we predicted suitable for male dispersal linked all patches, but some potential core areas appear to be relatively isolated for females. Reintroduction of wolverines to the Southern Rockies and Sierra- Nevadas has the potential to increase population size by \u3e50% and these regions may be robust to climate change. The Central Linkage Region is an area of great importance for metapopulation function, thus warranting collaborative strategies for maintaining high survival rates, high reproductive rates, and dispersal capabilities. Our analysis can help identify dispersal corridors, release locations for reintroductions, and monitoring targets. The process we used can serve as an example for developing collaborative, landscapescale, conservation priorities for data-sparse metapopulations

Abundance model selection results for small mammal species groups surveyed in the shrub-steppe and grassland regions of Wyoming, 2010–2012.

<p>Abundance model selection results for small mammal species groups surveyed in the shrub-steppe and grassland regions of Wyoming, 2010–2012.</p

Occasion-specific density estimates (individuals/km²; standard deviation in parentheses) averaged over all sampled sites for the most abundant small mammal species groups modeled from line transect surveys in Wyoming, 2010–2012.

<p>Occasion-specific density estimates (individuals/km²; standard deviation in parentheses) averaged over all sampled sites for the most abundant small mammal species groups modeled from line transect surveys in Wyoming, 2010–2012.</p

Modeled response of density (individuals/km²) of small mammal species groups to proportion of herbaceous cover or bare ground.

<p>Top panels show herbaceous cover, bottom panels show bare ground; dotted lines show 95% confidence interval. Panel A) shows white-tailed prairie dogs, B) least chipmunks, C) Wyoming ground squirrels, and D) leporids (<i>Sylvilagus</i> sp. and <i>Lepus townsendii</i>).</p