Introduced Lagomorphs as a Threat to “Native” Lagomorphs: The Case of the Eastern Cottontail (Sylvilagus floridanus) in Northern Italy

Eastern cottontails were introduced in Pinerolo (southwest of Torino), Italy, near the Pellice River, in 1966 (Spagnesi 2002). By the 1980s, the population expanded into the region of Piemonte with localized groups in the province of Alessandria (Prigioni et al. 1992), reaching 25–27 cottontails/km² in the late 1990s, and the percentage of cottontails in the total of all mammals killed on roads rose from 2.2% in 1995 to 6.0% in 1997 (Silvano et al. 2000). At the end of the 1990s, the species was present in the western part of Lombardia and in some localities in the south side of the Po River (Fig. 1). Presently, Eastern cottontails are also present in the regions of Veneto, Emilia Romagna, Marche, and Toscana in response to population growth and additional releases to increase the potential for small game harvesting. Meriggi (2001) observed that in release sites, cottontails preferred the successional and weedy vegetation with dense brushy cover along rivers where they can find cover from predators. He also speculated that cottontails might compete with native Lagomorphs (European hare, Lepus europaeus, and European rabbit, Oryctolagus cuniculus), especially in poor habitats, limiting their population size to a low level. A prerequisite of competition would be that Eastern cottontails have similar habitat requirements as other native Lagomorphs. In this chapter, we analysed the potential competition between Eastern cottontails, European hares and European rabbits by investigating the habitat requirements of Eastern cottontails in two areas of northern Italy.