An Ecosystem at Risk: The Intersection of Human Impacts and Sagebrush in the Wyoming Basins

USDA Forest Service Pacific Northwest Research Station (1,8) and Rocky Mountain Research Station (7), and USGS Forest and Rangeland Ecosystem Science Center (2,4,5,6) and Fort Collins Science Center (3)

Accelerated energy development and associated infrastructure, such as well pads, roads, powerlines, and pipelines, potentially influence a substantial proportion of the sagebrush ecosystem, especially in Wyoming and adjacent states.  For example, within the Green River Basin in Wyoming, >34,000 ha of native shrublands have been converted to well pads and access roads since 1964; geologic basins in this region contain the largest undeveloped onshore reserves of oil and natural gas in the contiguous USA.  Conservation and restoration of sagebrush communities are of special concern to land and wildlife management agencies, due to extensive habitat loss and degradation within this ecosystem.  Populations and habitats of a diverse suite of species closely allied with sagebrush communities, such as greater sage-grouse and pygmy rabbit, are considered to be at risk.  In response to concerns about environmental conditions in the sagebrush ecosystem, the Bureau of Land Management initiated a series of ecoregional assessments in sagebrush habitats.  The Wyoming Basins area is of high priority for regional assessment because of the juxtaposition of rapid energy development with some of the largest tracts of extant sagebrush (e.g., 17% of the sagebrush in the nation is in the Wyoming Basins Ecoregion).  Sagebrush-associated species of concern identified for the Wyoming Basins Ecoregional Assessment included 40 vertebrates and 64 vascular plants.   Species richness of vertebrates of concern was highest in southwestern Wyoming, where growth in oil and gas field development is exceptionally rapid.  We evaluated potential impacts of anthropogenic disturbance on sagebrush habitats and associated species by creating a “human footprint” model.  Predictive models of potential impacts of human disturbance on 5 example species in the assessment area--ferruginous hawk, greater sage-grouse, Brewer’s sparrow, pronghorn, and pygmy rabbit--suggested large-scale fragmentation and habitat degradation will be detrimental to these species.

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