Estimating golden eagle carrying capacity and wind power impacts through species distribution modeling

Abstract

Knowledge of species' habitat requirements, and the environmental conditions and resources needed for survival and reproduction are key factors in effective conservation management. We used species distribution modeling to study golden eagle (Aquila chrysaetos) habitat requirements. Additionally, we developed two different models to determine suitability at the nest-site and territory levels. We estimated the maximum number of predicted territories to infer the potential carrying capacity by developing a simulation based on our nest and territory models. As the species is known to avoid human disturbance, we also evaluated the potential risk of wind farms to predicted golden eagle territory areas. Our results show that slope preference (>10°) and avoidance of human settlements are key factors at nest sites, explaining 50% and 21% of the variance in the nest model, respectively. At the territory level, avoidance of human habitation is the most important factor (51%). As expected, areas predicted to have high occupancy probability are most abundant in northern Finland, where most of the current population breeds. Based on our simulation results, the species has an estimated 170,000 km2 of modeled habitat available that could carry 492–554 territories in Finland depending on the population size and habitat quantity, which dictate territory size. When examining wind farms at different stages of planning, we found that 18.9% of them were close to core areas in known nesting territories, and 1.4%–6.7% were close to core areas in simulated potential territories. Our results demonstrate how wind farms impact golden eagle population in Finland and must be considered in current and future planning.