How the South was won: current and potential range expansion of the crested porcupine in Southern Italy

Since the 1970s, the crested porcupine Hystrix cristata has expanded its range into Northern regions in Italy, where it was historically absent, helped by climatic change, legal protection, and forest re-expansion. In the past 10 years, a remarkable range expansion has also been observed in the southernmost Italian regions. The aim of our work was to summarize the distribution of this species in Southern Italy and assess potential range expansion under multiple future scenarios of global warming. We collected 1783 occurrence records of the crested porcupine through ad-hoc web pages, online platforms, and some data directly collected by authors (N = 976 occurrences between 1998 and 2008; N = 807 between 2008 and 2019). A remarkable increase in porcupine records occurred in Lucania, Campania, and Apulia regions, in Southern Italy, mostly along the coastlines. Species distribution models showed that porcupine presence is associated with warm temperatures and an intermediate level of precipitation. Although land-cover showed lower importance compared to climate, the species was positively associated with forests and negatively associated with agricultural, grasslands and shrublands, and urban landscapes. Model projections suggested that future global warming can improve suitability for porcupines in the Apennine ridge, including the Southern Calabria and the Aspromonte National Park. However, increase in drought and urbanization may reduce the habitat suitability for the crested porcupine in the Salento peninsula, limiting the success of the range expansion by this large rodent, and in Eastern Calabria, wih possible range contractions along the Tyrrhenian coast.