Late summer spatial behaviour of Alpine marmots Marmota marmota in the Eastern Italian Alps: effects of intrinsic and extrinsic drivers

Animal spatial behaviour is shaped by complex interactions between resource needs and ecological factors. Identifying drivers of spatial behaviour is crucial to understand variations in home range size, a central issue in vertebrate ecology. The Alpine marmot (Marmota marmota) is widespread in the mountainous regions of continental Europe, and its spatial ecology has been investigated previously. However, studies are lacking for the eastern Italian Alps. We studied the spatial behaviour of M. marmota in Paneveggio Pale di San Martino Natural Park, Italy. In the summer of 2022, we tracked the movements of 23 individually tagged marmots. We estimated the individual home range size and core area using perturbative hybrid residual maximum likelihood estimation (pHREML) in continuous-time movement models at 95% and 50% coverage levels. We analysed the variation in home ranges and core area size in relation to sex, age, number of individuals per family group, and the Difference Vegetation Index (NDVI) as a proxy of habitat quality. Home range and core area size did not vary with age or sex, but both were influenced by family group size and habitat quality. We found that M. marmota individuals living in areas with low NDVI values had larger home ranges. This finding may be linked to resource exploitation: when forage attributes are suboptimal M. marmota must travel greater distances to forage, likely to accumulate enough fat reserves to survive hibernation. These findings provide a first insight into the Alpine marmot's spatial behaviour in the eastern Italian Alps.