A scoping review of the scientific evidence base for rewilding in Europe

Restoring functional ecosystems is crucial to reversing the global biodiversity and climate crises. The concept of rewilding has gained increasing attention as a proactive tool for achieving ecosystem restoration quickly and at scale. However, the science of rewilding has been criticised for being largely theory-led rather than evidence based, a factor that continues to stymy policy actions. Here, we conduct a scoping review with the aim of mapping the nature and extent of the peer-reviewed literature that has measured outcomes of European rewilding projects. Our findings reveal significant growth in this area, although with a geographical bias towards the Netherlands and Scandinavian countries. Our synthesis of evidence shows that, although rewilding is not a biodiversity or climate panacea, there is a growing evidence base in support of theoretical propositions that it can restore biodiversity, deliver ecosystem services and support nature-based economies. To advance the field and address spatial disparity in reporting, we propose the establishment of country-specific networks of monitored and data-driven experimental rewilding projects, focused on national contexts. We also propose that the concept of standardizing the assessment of rewilding success across sites should be approached with caution, considering the site-specific and self-defining nature of rewilding outcomes. Lastly, we emphasize the importance of careful consideration by practitioners in terms of large herbivore refaunation efforts in Europe. Implementing comprehensive long-term plans to manage herbivore populations and address unforeseen effects is essential to mitigate welfare concerns, overgrazing, and reputational risks, while also maximizing biodiversity gains.