Abstract
The drive towards decarbonization has led countries to seek renewable energy sources to mitigate global warming. Wind energy is an attractive option due to its low cost and sustainability, but it poses significant risks to birds and bats through collisions and barotrauma with wind turbines. We examined the main ecological traits linked to wind turbine mortality in 214 bird and 19 bat species in peninsular Spain. We assessed the vulnerability of bird and bat assemblages to help understand the potential impact of wind energy development on the most vulnerable assemblages. Our findings indicate that bird and bat casualties were driven by morphological and ecological traits. For birds, scavenger species, those with partial migratory patterns, and aerial lifestyles were most affected by turbine collisions. We also found that vulnerability was positively correlated with observed mortality rates at the province level, but the effect was weaker for birds. Sensitive areas for birds and bats are located in southern, south-eastern, and central Spain, with birds showing additional vulnerability in western and northern regions, while future wind energy development affects bats more in eastern Spain. Our research highlights the importance of mitigating impacts on vulnerable bird and bat species, as well as abundant species. The study highlights the potential risk of ecosystem function loss for bird and bat assemblages due to wind energy projects. We provide spatial tools to identify high-vulnerability areas, guiding energy development to minimize ecological impacts. This work calls on authorities to implement measures to protect species and preserve essential ecosystem functions.