Factors associated with extirpation of sage-grouse: Chapter 18

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Geographic ranges of Greater Sage-Grouse (Centrocercus urophasianus) and Gunnison Sage-Grouse (C. minimus) have contracted across large areas in response to habitat loss and detrimental land uses. However, quantitative analyses of the environmental factors most closely associated with range contraction have been lacking, results of which could be highly relevant to conservation planning. Consequently, we analyzed differences in 22 environmental variables between areas of former range (extirpated range), and areas still occupied by the two species (occupied range). Fifteen of the 22 variables, representing a broad spectrum of biotic, abiotic, and anthropogenic conditions, had mean values that were significantly different between extirpated and occupied ranges. Best discrimination between extirpated and occupied ranges, using discriminant function analysis (DFA), was provided by five of these variables: sagebrush area (Artemisia spp.); elevation; distance to transmission lines; distance to cellular towers; and land ownership. A DFA model containing these five variables correctly classified 80% of sage-grouse historical locations to extirpated and occupied ranges. We used this model to estimate the similarity between areas of occupied range with areas where extirpation has occurred. Areas currently occupied by sage-grouse, but with high similarity to extirpated range, may not support persistent populations. Model estimates showed that areas of highest similarity were concentrated in the smallest, disjunct portions of occupied range and along range peripheries. Large areas in the eastern portion of occupied range also had high similarity with extirpated range. By contrast, areas of lowest similarity with extirpated range were concentrated in the largest, most contiguous portions of occupied range that dominate Oregon, Idaho, Nevada, and western Wyoming. Our results have direct relevance to conservation planning. We describe how results can be used to identify strongholds and spatial priorities for effective landscape management of sage-grouse.

Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Factors associated with extirpation of sage-grouse: Chapter 18
Volume 38
Year Published 2011
Language English
Publisher University of California Press
Publisher location Berkeley, CA
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 24 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Greater Sage-Grouse: Ecology and Conservation of a Landscape Species and Its Habitats
First page 451
Last page 474
Online Only (Y/N) N
Additional Online Files (Y/N) N