A regionally varying habitat model to inform management for greater sage-grouse persistence across their range

• Published in: Global ecology and conservation 2023-01, Vol.41, p.e02349, Article e02349
• Main Authors: Wann, Gregory T., Van Schmidt, Nathan D., Shyvers, Jessica E., Tarbox, Bryan C., McLachlan, Megan M., O’Donnell, Michael S., Titolo, Anthony J., Coates, Peter S., Edmunds, David R., Heinrichs, Julie A., Monroe, Adrian P., Aldridge, Cameron L.
• Format: Article
• Language: English
• Subjects: Centrocercus urophasianus; Collaborative management; Greater sage-grouse; Habitat suitability model; Lek persistence; Mixed effects model
• ISSN: 2351-9894; 2351-9894
• DOI: 10.1016/j.gecco.2022.e02349

Identifying habitat needs for species with large distributions is challenging because species-habitat associations may vary across scales and regions (spatial nonstationarity). Furthermore, management efforts often cross jurisdictional boundaries, complicating the development of cohesive conservation strategies among management entities. The greater sage-grouse (Centrocercus urophasianus) is a rapidly declining species that spans 11 U.S. states and responds to habitat conditions across a wide range of spatial scales and regions. Allowing for regional variance in species-habitat associations and suitability predictions could systematically identify important habitats at levels relevant to management. We collaboratively developed a model with Bureau of Land Management (BLM) biologists that: (1) evaluated the scale of effect for different environmental covariates; (2) accounted for regional differences in population-level responses; and (3) predicted probabilities of persistence across the U.S. occupied range. We modeled range-wide lek persistence data (6615 communal breeding sites classified as active or inactive) as a function of environmental covariates. Environmental covariates included sagebrush cover, pinyon-juniper cover, topography, precipitation, point and line disturbance densities, and landscape configuration metrics. Our model treated habitat assessment areas – regionally delineated by BLM biologists – as random intercepts and slopes that allowed for geographic variation in species-habitat associations and predicted probabilities of lek persistence. Our final model indicated support for 12 environmental covariates predicting lek persistence at scales extending between 1- to 15-km radii from lek centers, and a covariate measuring distance to the occupied range boundary. Five of these covariates showed significant regionally varying responses: sagebrush clumpiness (a measure of habitat aggregation), pinyon-juniper cover, point disturbance of anthropogenic features such as energy infrastructure and communication towers, elevation, and a topographic index associated with mesic habitats. This spatial nonstationarity indicates unitary range-wide recommendations, or rules-of-thumb with respect to their effects on lek persistence, may be problematic for these environmental conditions. For covariates that did not include random slopes, and which were potentially amenable to management actions, we found that leks were predicted to become extirpated when sag