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Steven E. Hanser

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The Greater Sage-Grouse (Centrocercus urophasianus), endemic to western North Amer-ica, is of great conservation interest. Its popula-tions are tracked by spring counts of males at lek sites. We explored the relations between trends of Greater Sage-Grouse lek counts from 1997 to 2007 and a variety of natural and anthropogenic fea-tures. We found that trends were correlated with several habitat features, but not always similarly throughout the range. Lek trends were positively associated with proportion of sagebrush (Artemisia spp.) cover, within 5 km and 18 km. Lek trends had negative associations with the coverage of agriculture and exotic plant species. Trends also tended to be lower for leks where a greater pro-portion...
Categories: Publication; Types: Citation
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Spatial patterns influence the processes that maintain Greater Sage-Grouse (Centrocercus urophasianus) populations and sagebrush (Artemisia spp.) landscapes on which they depend. We used connectivity analyses to: (1) delineate the dominant pattern of sagebrush landscapes; (2) identify regions of the current range-wide distribution of Greater Sage-Grouse important for conservation; (3) estimate distance thresholds that potentially isolate populations; and (4) understand how landscape pattern, environmental disturbance, or location within the spatial network influenced lek persistence during a population decline. Long-term viability of sagebrush, assessed from its dominance in relatively unfragmented landscapes, likely...
Categories: Publication; Types: Citation
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Recent analyses of Greater Sage-Grouse (Centrocercus urophasianus) populations indicate substantial declines in many areas but relatively stable populations in other portions of the species? range. Sagebrush (Artemisia spp.) habitats neces-sary to support sage-grouse are being burned by large wildfires, invaded by nonnative plants, and developed for energy resources (gas, oil, and wind). Management on public lands, which con-tain 70% of sagebrush habitats, has changed over the last 30 years from large sagebrush control projects directed at enhancing livestock grazing to a greater emphasis on projects that often attempt to improve or restore ecological integrity. Never-theless, the mandate to manage public lands...
Categories: Publication; Types: Citation
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Connecting seasonal ranges of migratory birds is important for understanding the annual template of stressors that influence their populations. Brewer’s sparrows (Spizella breweri) and sagebrush sparrows (Artemisiospiza nevadensis) share similar sagebrush (Artemisia spp.) habitats for breeding but have different population trends that might be related to winter location. To link breeding and winter ranges, we created isoscapes of deuterium [stable isotope ratio (δ) of deuterium; δ2H] and nitrogen (δ15N) for each species modeled from isotope ratios measured in feathers of 264 Brewer’s and 82 sagebrush sparrows and environmental characteristics at capture locations across their breeding range. We then used feather...
Categories: Publication; Types: Citation; Tags: Oecologia
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Small mammal communities living in sagebrush (Artemisia spp.) may be sensitive to habitat isolation and invasion by exotic grass species. Yet there have been no spatially explicit models to improve our understanding of landscape-scale factors determining small mammal occurrence or abundance. We live-trapped small mammals at 186 locations in the Wyoming Basin Ecoregional Assessment area to develop species distribution (habitat) models for each species. Most small mammal species (n = 14) were trapped at a only few locations. As a result, we developed a small mammal model only for the deer mouse (Peromyscus maniculatus). Deer mice were associated with areas having moderately productive habitat as measured by Normalized...
Categories: Publication; Types: Citation
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