Open-File Report 2014-1163
Greater sage-grouse (Centrocercus urophasianus, hereafter referred to as “sage-grouse”) populations are declining throughout the sagebrush (Artemisia spp.) ecosystem, including millions of acres of potential habitat across the West. Habitat maps derived from empirical data are needed given impending listing decisions that will affect both sage-grouse population dynamics and human land-use restrictions. This report presents the process for developing spatially explicit maps describing relative habitat suitability for sage-grouse in Nevada and northeastern California. Maps depicting habitat suitability indices (HSI) values were generated based on model-averaged resource selection functions informed by more than 31,000 independent telemetry locations from more than 1,500 radio-marked sage-grouse across 12 project areas in Nevada and northeastern California collected during a 15-year period (1998–2013). Modeled habitat covariates included land cover composition, water resources, habitat configuration, elevation, and topography, each at multiple spatial scales that were relevant to empirically observed sage-grouse movement patterns. We then present an example of how the HSI can be delineated into categories. Specifically, we demonstrate that the deviation from the mean can be used to classify habitat suitability into three categories of habitat quality (high, moderate, and low) and one non-habitat category. The classification resulted in an agreement of 93–97 percent for habitat versus non-habitat across a suite of independent validation datasets. Lastly, we provide an example of how space use models can be integrated with habitat models to help inform conservation planning. In this example, we combined probabilistic breeding density with a non-linear probability of occurrence relative to distance to nearest lek (traditional breeding ground) using count data to calculate a composite space use index (SUI). The SUI was then classified into two categories of use (high and low-to-no) and intersected with the HSI categories to create potential management prioritization scenarios based oninformation about sage-grouse occupancy coupled with habitat suitability. This provided an example of a conservation planning application that uses the intersection of the spatially-explicit HSI and empirically-based SUI to identify potential spatially explicit strategies for sage-grouse management. Importantly, the reported categories for the HSI and SUI can be reclassified relatively easily to employ alternative conservation thresholds that may be identified through decision-making processes with stake-holders, managers, and biologists. Moreover, the HSI/SUI interface map can be updated readily as new data become available.
First posted July 31, 2014
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Coates, P.S., Casazza, M.L., Brussee B.E., Ricca, M.A., Gustafson, K.B., Overton, C.T., Sanchez-Chopitea, E., Kroger, T., Mauch, K., Niell, L., Howe, K., Gardner, S., Espinosa, S., and Delehanty, D.J., 2014, Spatially explicit modeling of greater sage-grouse (Centrocercus urophasianus) habitat in Nevada and northeastern California—A decision-support tool for management: U.S. Geological Survey Open-File Report 2014-1163, 84 p., https://dx.doi.org/10.3133/ofr20141163.
ISSN 2331-1258 (online)
Methods and Results
Region-Wide Habitat Suitability Index and Implementation for Conservation Planning
Implementation of the Region-Wide HSI Map for Conservation Planning—An Example
Appendix A. Supplemental Material for Buffalo-Skedaddle RSF Modeling
Appendix B. Supplemental Material for Butte-Buck-White Pine RSF Modeling
Appendix C. Supplemental Material for Cortez RSF Modeling
Appendix D. Supplemental Material for Desert-Tuscarora RSF Modeling
Appendix E. Supplemental Material for Gollaher-O’Neil RSF Modeling
Appendix F. Supplemental Material for Lincoln-Schnell-Snake RSF Modeling
Appendix G. Supplemental Material for Lone Willow RSF Modeling
Appendix H. Supplemental Material for Midway RSF Modeling
Appendix I. Supplemental Material for Sheldon RSF Modeling
Appendix J. Supplemental Material for South Fork-Ruby Valley RSF Modeling
Appendix K. Supplemental Material for Toiyabe RSF Modeling
Appendix L. Supplemental Material for Virginia Mountains RSF Modeling