Modelling the habitat requirements of invasive Eastern Cottontail (Sylvilagus floridanus) introduced to Italy

Abstract

We analysed the spatial distribution of Eastern Cottontail (Sylvilagus floridanus) and its relationship with the habitat attributes of the agro-ecosystems in north-western Italy. We used generalised linear models to analyse the relationship between the occurrence of the cottontail and a series of landscape-level variables. Hierarchical partitioning was used to estimate the independent contribution of these variables. Our analysis showed that cottontail is typically a lowland species, in that it selected municipalities below 400 m a.s.l. and avoided higher elevations. Cottontails were more likely to occur where the edges of meadows and crop fields were higher. This might indicate the importance of these herbaceous habitats in cottontail feeding behaviour and also the significance of edge vegetation in providing cover. In addition, the extent of the hydrographic network positively affected cottontail presence, probably due to the permanent vegetation cover associated with the banks of rivers, streams and channels of the otherwise intensively cultivated and densely inhabited Po Plain. On the other hand, a prevalence of woodlands, tree plantations and large pastures negatively affected cottontail presence. This is surprising, because these habitats usually encourage cottontail presence in their native range. In general, however, cottontails prefer small woodlots and utilise only the edges of forests, while in Italy forests and pastures are large and typically located in hilly and mountain areas generally avoided by this species. In conclusion, our results confirm that the cottontail is an edge species whose presence is encouraged by crop margins, natural herbaceous habitats and extensive hydrographic networks with the associated riverside vegetation. These characteristics are common in the Po Plain and are likely to facilitate a further expansion of cottontail.