Wind turbines kill bats---cascading impacts cause ecological collapse

Wind energy production is growing rapidly worldwide in an effort to reduce greenhouse gas emissions. However, wind energy production is not environmentally neutral. Negative impacts on volant animals, such as bats, include fatalities at turbines and habitat loss due to land-use change and displacement. Siting turbines away from ecologically sensitive areas and implementing measures to reduce fatalities are critical to protecting bat populations. Restricting turbine operations during periods of high bat activity is the most effective form of mitigation currently available to reduce fatalities. Compensating for habitat loss and offsetting mortality are not often practiced, because meaningful offsets are lacking. Legal frameworks to prevent or mitigate the negative impacts of wind energy on bats are absent in most countries, especially in emerging markets. Therefore, governments and lending institutions are key in reconciling wind energy production with biodiversity goals by requiring sufficient environmental standards for wind energy projects. Wind power generation has become a pillar of renewable energy generation worldwide in the fight against global warming (GWEC 2023). However, wind energy generation is not environmentally neutral; that is, wind turbines can have negative impacts on local habitats and the organisms that live in them (Saidur et al. 2011, Gibson et al. 2017). For example, the construction of wind turbine facilities may fragment and degrade habitats, making them unsuitable for breeding, foraging, commuting, and migration (Shaffer and Buhl 2016, Reusch et al. 2022). Furthermore, large numbers of volant vertebrates, such as raptors and bats (Thaxter et al. 2017), are killed by wind turbines. With bats accounting for the majority of vertebrate fatalities at wind turbines, global wind energy production is the leading cause of multiple mortality events in bats (O'Shea et al. 2016). Bats are an essential component of mammalian diversity (Simmons and Cirranello 2024). They are key parts of ecological communities and are important bioindicators in almost all ecosystems (Jones et al. 2009). They also provide ecosystem services to agriculture and forestry (Kunz et al. 2011). However, more than one-third of bat species are threatened or data deficient, according to the International Union for Conservation of Nature's (IUCN) standards, and about half show negative population trends (Frick et al. 2020). Reducing the negative impacts of wind energy on bats is an important conservation objective. Over the past two decades, the body of literature on the impacts of wind energy on bats and effective mitigation measures has grown considerably, although we still lack data for many regions of the world, particularly for countries with emerging markets (figure 1). In the present article, we review the interactions of bats with wind turbines, discuss the limitations of our understanding on a global scale, and highlight effective measures to mitigate this green–green dilemma.