Environmental favorability models as a tool to support trophic rewilding initiatives

Trophic rewilding is considered a conservation measure that aims to restore the trophic interactions. In north-central Portugal, the Iberian wolf (Canis lupus signatus) is endangered mainly due to human persecution, triggered by wolf depredation on livestock. Several initiatives have occurred in this area to increase wolf wild prey availability by reintroducing/reinforcing roe deer (Capreolus capreolus) populations. However, the success of trophic rewilding initiatives relies on up-to-date scientific evidence, considering both ecological and social settings. Favorability models can be used to infer the most suitable habitats for roe deer settlement and expansion by analyzing the environmental variables known to influence species ecology and behavior. In this study, we infer how the prey habitat favorability can contribute to plan prey populations reinforcement processes as a tool for trophic chain restoration. Using 330 camera traps, we monitored the roe deer population over 8,940 km(2) in north-central Portugal. Field data were used to evaluate the environmental determinants of roe deer presence. By using the favorability function, we created a spatially explicit gradient of habitat favorability that allowed us to define key areas for the application of management measures. The selected sites are strategically positioned to promote the natural expansion of established roe deer populations and overlap the current distribution of Iberian wolf. These results are an important step toward the restoration of the trophic chain and to reduce human-wolf conflicts. Our proposal paves the way for future rewilding initiatives, especially where prey species are central to the survival of top predators.