Abstract
Mitigating impacts of wind energy development on wildlife is important for conservation and public acceptance of this energy source. We provide an overview of approaches to mitigate impacts of onshore wind energy development on wildlife, following steps in the mitigation hierarchy, including avoidance, minimization, and compensatory mitigation. Planning and avoiding predicted high-risk areas is fundamental to reduce impacts on birds and bats. Contrary to avoidance, once facilities are built, options to minimize impacts need to be tailored to species at the specific site, and can be limited especially for bats. Curtailing wind turbine operations is the only approach proven effective at reducing bat mortality. While curtailment may in part also be effective for birds, micro-siting and repowering also are likely to reduce mortality. Compensation should be considered only as part of the mitigation hierarchy when unforeseen or unavoidable impacts remain. Offsite habitat-based compensatory measures may provide the best offsets for incidental bird and bat mortality. While the conceptual framework and predictive modelling for compensatory measures are well-established, empirical evidence demonstrating effectiveness and achievement of no-net loss for wildlife populations is lacking. Similarly, few studies have evaluated effectiveness of minimization measures and other forms of mitigation. Evaluating effectiveness of pre- construction wildlife assessments and habitat modeling in predicting wildlife mortality at wind facilities remains a research need. Additionally, lack of population data for many species of wildlife hinders knowledge of population-level impacts and effectiveness of mitigation measures. Policy revisions and regulation may be necessary, especially when wildlife agencies have little or no authority in decision-making or no protection for wildlife beyond voluntary measures.