Causal mechanisms for negative impacts of energy development inform management triggers for sagebrush birds

Abstract

AbstractEstimated population trends can identify declining species to focus biological conservation, but monitoring may fail to illuminate causes of population change and strategies for reversing declines. Monitoring programs can relate trends with environmental attributes to test causal hypotheses, but typical analytical approaches do not explicitly support causal inference, diluting available data for informing conservation. The U.S. Bureau of Land Management (BLM) extended Integrated Monitoring in Bird Conservation Regions with a quasi‐experimental sampling design over a 10‐year period (2010–2019) to evaluate the impacts of oil and gas development on sagebrush birds within the Atlantic Rim Natural Gas Field Development Project in southern Wyoming. We analyzed resulting data using a multiscale community occupancy model to estimate trends in species occupancy and richness relevant to management triggers. Additionally, we employed path analysis to evaluate mechanisms underlying observed trends to inform potential management responses. Fine‐scale occupancy for sage thrasher (Oreoscoptes montanus) declined within the high‐development stratum at a rate sufficient to meet an a priori management trigger established by the BLM. Two additional sagebrush‐associated species, Brewer's (Spizella breweri) and sagebrush sparrow (Artemisiospiza nevadensis), exhibited negative development relationships with trend, as did overall species richness, and richness of grassland, sagebrush, and generalist guilds. We identified well pad density and invasive plants associated with energy development as causal factors contributing to these negative development impacts. We demonstrate an analytical approach for both estimating occupancy trends and identifying underlying causes to inform conservation action. Reducing the development footprint, including well pad density and associated invasive plants, could help reduce or limit impacts on birds within this landscape.