Abstract
One of the potential negative impacts of invasive species is competitive exclusion of native species that have similar
or identical ecological niches. Even with extensive knowledge of the similarities between the diets and habitats of invasive and
native species, it is difficult to predict the long-term consequences of species interactions over varying spatial and temporal
scales with variable resource levels. Here we apply a hierarchical Bayesian model to examine the roles of spatial variations in
land use and population densities of the introduced raccoon Procyon lotor and civet Paguma larvata on the population density of the native raccoon dog Nyctereutes procyonoides in the south-eastern Boso Peninsula, central Japan. Our analysis reveals that
introduced raccoons negatively affect raccoon dog populations. Substantial numbers of native raccoon dogs and the two invasive
mammals have been removed by trapping to control damage to crops. Despite these control measures, the invasive raccoon
population has increased, which will likely lead to a reduction in the native raccoon dog population. It is thus imperative to
monitor the population trends of native raccoon dogs to conserve this species.
