Application of modelling tecniques to manage a population of grey squirrels (Sciurus carolinensis) in Lombardy, Northern Italy, and analysis of parameters estimates used in simulations.

Grey squirrel (Sciurus carolinensis), an invasive alien species, is currently replacing the native Eurasian red squirrel (Sciurus vulgaris) in British Isles and north-west Italy. Grey squirrel has recently been reported in the Ticino Park (Lombardy region, NW Italy) and the species is likely to spread in the woodlands connecting Italy to other European countries. We used GRASS Geographical Information System (GIS) and Spatially Explicit Population Dynamics Models (SEPM) as a conservation tool to predict the spread of grey squirrels and to test different management options in the Ticino Regional Park and surrounding areas in a 40 years time frame. The integrated approach of SEPM and GIS allowed us to suggest public administration a cost effective action plan to stop the invasion process. We also analyse the parameters used in the model highlighting some missing data in literature: we can address future field study with the aim to improve model performance.