Disturbance affects biotic community composition at desert wind farms

Abstract

Context The global benefits of increased renewable energy production may come at a cost to local biotic communities and even regional ecosystems. Wind energy developments, in particular, are known to cause bird and bat mortalities, and to fragment habitat for terrestrial vertebrates within developed project areas. Effects on species sensitive to wind turbines (and increased prevalence of species tolerant to this disturbance) might alter community-level patterns of occurrence, with potentially detrimental changes to wildlife habitat and ecosystem health. Aims The present study assessed whether wind energy developments produced downstream ecological costs. Specifically, community composition and diversity were compared between wind farms and nearby areas without energy development. Methods Traditional diversity measures and non-metric multidimensional scaling (NMDS) were used to map ecological dissimilarity across four wind farms and five reference (control) areas in Southern California, USA. Key results Wind farms had more noise and road disturbance than sites without turbine installations. Noise and disturbance were correlated with reduced plant richness, particularly for endemic plant species and, conversely, with increased non-native plant richness. Animal communities at wind farms were less diverse, with fewer species and lower evenness relative to reference areas with minor or no disturbances. Wind farms had fewer rare and unique species and, for some species of avian predators, encounter rates were lower at wind farms. Conclusions Renewable wind energy may indeed cause shifts in local communities. Although wind farms still supported many of the same species found in natural areas, suggesting that renewable wind energy facilities can provide useable habitat for some wildlife, these communities were also less rich and diverse. Implications Non-native species were more prevalent at wind farms, which may then facilitate further invasions into surrounding habitats. In addition, reduced overall plant and predator diversity at wind farms, and lower encounter rates for specific taxa (particular birds), may significantly affect community structure and function.