Assessment of Habitat Threats to Shrublands in the Great Basin: A Case Study
Authored By: M. M. Rowland, L. H. Suring, M. J. Wisdom
Mary M. Rowland, Lowell H. Suring, and Michael J. Wisdom
USDA Forest Service, PNW Research Station (1,3) and Terrestrial Wildlife Ecology Unit (2)
The sagebrush ecosystem is one of the most imperiled in the USA. In the Great Basin Ecoregion and elsewhere, catastrophic wildland fires often are followed by the invasion of cheatgrass, a process that has eliminated or altered millions of hectares of sagebrush and other native shrublands. Sagebrush communities in the Great Basin also are threatened by displacement from encroaching pinyon-juniper woodlands. Despite these losses, the Great Basin retains some of the largest remaining expanses of sagebrush in the nation, most of which is federally managed. Concomitant with threats to native vegetation are declining habitats and populations of sagebrush-associated species. To address these issues, we conducted a regional assessment of habitat threats for 40 sagebrush-associated vertebrates of conservation concern in the Great Basin. Our goals were to (1) evaluate habitat conditions for species of concern for conservation planning and management, (2) demonstrate the application of newly developed methods of regional assessment of threats in arid shrubland communities, and (3) describe implications of results for management. Our analyses suggested that >55% (≈4.8 million ha) of sagebrush in the Great Basin is at moderate or high risk of being displaced by cheatgrass over the next 30 years. Moreover, cheatgrass threatens other shrubland communities, particularly salt desert scrub (96%, or ≈7.1 million ha at moderate or high risk). Substantial areas of sagebrush (41%; ≈2.0 million ha) also were predicted to be at moderate or high risk of displacement by pinyon-juniper woodlands in the eastern Great Basin. Of the 40 vertebrate species we considered, potential habitat loss to cheatgrass could exceed 65% (≈8 million ha) for some species. Maintenance and restoration of native shrublands in the Great Basin will require both active and passive management to mitigate the formidable threats posed by cheatgrass and pinyon-juniper woodlands.
Biodiversity Session - Thursday Afternoon
corresponding author:
Mary M. Rowland
USDA Forest Sevice
Pacific Northwest Research Station
1401 Gekeler Lane
La Grande, OR 97850
541-962-6582
mrowland@fs.fed.us
