Land cover and climatic conditions as potential drivers of the raccoon (Procyon lotor) distribution in North America and Europe

Abstract

The raccoon is listed among the invasive alien species of EU concern requiring management actions. Projections of its global distribution have been mainly based on climatic variables so far. In this study, we aim to address the impact of land cover (LC) on the raccoon distribution in North America and Europe. First, we identified the LC types in which the observation sites are predominantly located to derive preferred LC types. Second, we used an ecological niche modelling (ENM) approach to evaluate the predictive power of climatic and LC information on the current distribution patterns of raccoons in both ranges. Raccoons seem to be more often associated to forested areas and mixed landscapes, including cropland and urban areas, but underrepresented in vegetation-poor areas, with patterns largely coinciding in both ranges. In order to compare the predictive power of climate variables and land cover variables, we conducted principal component analyses of all variables in the respective variable sets (climate variables and land cover variables) and used all PC variables that together explain 90% of the total variance in the respective set as predictors. Land cover only models resulted in patchy patterns in the projected habitat suitabilities and showed a higher performance compared to the climate only models in both ranges. In Europe, the land cover habitat suitability seems to exceed the current observed occurrences, which could indicate a further spread potential of the raccoon in Europe. We conclude that information on land cover types are important drivers, which explain well the spatial patterns of the raccoon. Consideration of land cover could benefit efforts to control invasive carnivores and contribute to better management of biodiversity, but also human and animal health.

Evidence of predation pressure on sensitive species by raccoons based on parasitological studies

“…The negative impacts of raccoon predation have already been demonstrated through case studies (e.g., Wüstemann, 2002 ; Schneeweiβ and Breu, 2013 ; Egeter et al, 2015 ; Nehring, 2018 ; Oe et al, 2020 ; Cichocki et al, 2021 ). The exponential growth of raccoon populations and the effective exploitation of ecological niches in the study areas, combined with their dietary habits, exacerbate the pressure on occurrence-sensitive animal species ( Nehring, 2018 ; Salgado, 2018 ; Kochmann et al, 2021 ; Cunze et al, 2023 ).…”

“…The strong population increase of raccoons and their ongoing spread (e.g. Cunze et al, 2023 ) especially in protected natural areas, increase the predation risk for occurrence-sensitive animal species. Due to the raccoon's high dispersal ability and its dietary ecology, which allows it to inhabit nearly all natural habitats, it is suspected to be responsible for the regional decline of numerous native species.…”