Jason D. Tack, Joseph T. Smith, Kevin E. Doherty, Patrick J. Donnelly, Jeremy D. Maestas, Brady W. Allred, Jason Reinhardt, Scott L. Morford, David E. Naugle, "Regional Context for Balancing Sagebrush- and Woodland-Dependent Songbird Needs with Targeted Pinyon-Juniper Management", Rangeland Ecology & Management, Volume 88, 2023, Pages 182-191, ISSN 1550-7424.
In the western United States, pinyon-juniper woodlands have expanded by as much as sixfold among sagebrush landscapes since the late 19th century, with demonstrated negative impacts to the behavior, demography, and population dynamics of species that rely on intact sagebrush rangelands. Notably, greater sage-grouse (Centrocercus urophasianus) are unable to tolerate even low conifer cover, which can result in population declines and local extirpation, whereas removing expanding conifer cover has been demonstrated to increase sage grouse population growth rates and sagebrush obligate songbird abundance. Yet conifer management among sagebrush landscapes has been met with concerns about unintended impacts to species that rely on conifer woodlands, notably the pinyon jay (Gymnorhinus cyanocephalus), whose population declines are distinctive among birds breeding in pinyon-juniper woodlands. Spatial models of bird abundance can help management prioritize future actions in light of multiple species requirements, while also providing a framework to retroactively test the impact of past treatments. We used Breeding Bird Survey data to model indices to abundance in relation to multiscale habitat features including landcover, fire, topography, and climate variables for nine songbird species reliant on sagebrush and pinyon-juniper woodlands for breeding. Predictive maps allowed us to also examine the overlap of conifer management conducted by the Sage Grouse Initiative (SGI), which targets management of early successional conifers among priority sage-grouse habitats, with predicted indices to abundance of songbirds. Our findings demonstrate that targeted sage grouse habitat restoration under SGI was not at odds with protection of pinyon jay populations. Rather, conifer management has largely occurred among northern sagebrush landscapes where models suggest that past cuts likely benefit Brewer's sparrow and sage thrasher while avoiding pinyon jay habitats.