Wildlife health in environmental impact assessments: are we missing a key metric?

Environmental impact assessments (EIAs) aim to assess the predicted effects of future projects on the environment, human health, and the economic potential of a region. They are an instrumental tool for sustainable development and to reduce the impact of large-scale industrial projects on biodiversity. The accurate assessment of the effects of projects on wildlife populations has a variety of ecological, cultural, and economic implications. However, assessments are commonly done using indirect indicators such as the predicted impact of changes in the quantity and quality of wildlife habitat and (or) predicted changes in nonspecific wildlife population metrics (e.g., relative abundance). In recent decades, the interpretation of wildlife health has moved from the classical dichotomous state of "disease presence/absence" to a broader concept that integrates the interaction of biological, social, and environmental health determinants. We sought to determine how wildlife health metrics are used in EIA processes and propose a framework to characterize, quantify, and monitor wildlife health in future EIAs. First, we performed a targeted review of EIA documents from three jurisdictions in Canada to characterize the relevance and use of "wildlife health" in these documents. Then, we reviewed case studies and research examples to understand wildlife health in different contexts associated with conservation biology to propose a framework to incorporate wildlife health into baseline monitoring and mitigation processes in EIAs. Our targeted review illustrates that while wildlife health and related terminology is often invoked in the main and specific objectives of EIAs, it is rarely tracked and quantified in EIAs and related processes. We identified approaches that can be used to effectively incorporate wildlife health in EIAs, including context specific wildlife health metrics, participatory epidemiology, community-based sampling, and local ecological knowledge. We illustrate case studies where wildlife health can facilitate the inclusion of communities, Indigenous governments, and local ecological knowledge into the evaluation process of projects and developments and into comanagement practices of wildlife. Our work highlights the critical need to move towards incorporating wildlife health into EIA processes to provide a more direct and holistic perspective on the potential environmental impacts and improve the opportunities for early implementation of mitigation measurements.