Long-term assessment of roe deer reintroductions in North-East Spain: A case of success

Worldwide species relocations are increasingly becoming an important part of species recovery programmes and ecosystem restoration initiatives. Monitoring reintroduced populations after release, in addition to understanding which factors affect translocations, is fundamental to understand the reintroduction process and to maximize the success of future interventions. By using boosted regression trees we evaluated the contribution of roe deer Capreolus capreolus reintroductions (1971–2008) to the current distribution of this species in Catalonia (Spain), and a partial least square regression approach was used to evaluate the influence of some variables as key for the roe deer reintroduction success. Our results show that roe deer currently occupies 85% of Catalonia territory, which represents an almost six-fold increase since the beginning of the 90s. Proximity to the nearest reintroduction nuclei was identified as one of the main drivers positively associated to the current distribution of roe deer in Catalonia, whereas the number of years after the first reintroductions and the number of animals released were important to the success of the reintroductions. We recommend the reintroduction of roe deer to release sites that contain large and suitable patches of habitat and that are sufficiently close to allow population continuity.