Greater sage-grouse (Centrocercus urophasianus) occupy a small fraction of their former range and are now threatened by extinction. Recent connectivity assessments for the greater sage-grouse in the Columbia Basin, Washington, provide an opportunity to (1) evaluate approaches for parameterizing resistance models based on sage grouse specifically or the concept of landscape integrity, (2) derive parameters from expert or empirical data, and (3) explore the influence of scale on model accuracy. This study looked at various models to try and better understand landscape resistance (i.e., how landscape features affect movement or gene flow of species) for sage grouse. Specifically, the study expored the ability to predict greater sage-grouse movement paths, genetic isolation, and patterns of lek occupancy.
For the study, two opinion-based models and two sets of empircal, data-driven models were evaluated. One of the opinion-based models was based on opinions of leaders in the field and the other was based on a landscape integrity model based on expert opinion that assumed lower human footprint areas would provide less landscape resistance for sage grouse.
Two groups of empirical models were also evaluated. Within these models there were numerous hypothesis. One empircal model focused on the relationship of gene flow to landscape features, and the other considered lek (i.e., breeding) occurrence and the influence of environmental and human factors on breeding sites.
Can this information be extrapolated to other sage grouse populations outside of Washington? Across the West, sage grouse populations are the same species and transmission lines are nationally standardized. That said, research has not yet been conducted on populations outside of Washington to scientifically determine if transmission lines would offer the same level of resistance.