Vulnerability of bats in Australia to wind turbine mortality: a trait-based assessment

Wind turbine collisions are a leading cause of bat mortality globally, yet the vulnerability of Australian bat taxa remains poorly understood. Trait-based assessments offer a valuable method for evaluating mortality risk in the absence of data on species- and region-specific turbine interactions. Behavioural and morphological traits are strongly associated with bat fatalities at wind farms globally. Here, we use a trait-based approach to identify the relative vulnerability of bat genera to the increasing threat of wind turbine fatalities in Australia. Through a global literature review, we identified three traits associated with increased mortality rates: foraging guild, movement distance, and wing morphology. For each trait we estimated the level of sensitivity at the genus level based on available published data. Sensitivity scores were summed to produce an overall vulnerability score. Our assessment identified Saccolaimus and Taphozous (Emballonuridae); Austronomus, Chaereophon, Micronomus, Ozimops, and Setirostris (Mollosidae); Falsistrellus (Vespertilionidae); and Miniopterus (Miniopteridae); as the most vulnerable genera. Pteropus (Pteropodidae) was assessed as high vulnerability for wing morphology and movement distance but low for foraging guild (as a non-aerial forager). However, because of their exceptional mobility, we assessed Pteropus as high overall vulnerability. We also attributed a confidence score to trait estimates, which reflected data availability. Confidence was rated as relatively high for foraging guild (61% genera rate as high) and wing morphology (50% high), and lowest for movement distance (14% high). Our framework provides a timely foundation for predicting mortality risk from the rapid expansion of wind energy infrastructure in Australia, which requires urgent conservation assessment and implementation of management actions to minimise the impacts. Our trait-based assessment also provides direction for targeted research to better understand and quantify the threat of wind turbine mortalities to populations of Australian bats.