Assessing the Co-Occurrence of European Pine Marten (Martes martes) With Humans and Domestic Cats on a Mediterranean Island

Abstract

Anthropogenic activities often lead to changes in the distribution and behavior of wild species. The mere presence of humans and free-roaming domestic cats (Felis catus) can affect wildlife communities; however, responses to these disturbances might not be ubiquitous and may vary with local conditions. We investigated European pine marten's (Martes martes) distribution on Elba Island, Italy, where the species is the only wild carnivore. In this system, pine martens act as the top predator, and human presence is mostly driven by seasonal tourism. We evaluated (1) pine marten's occurrence in relation to vegetation type and elevation and the potential effects of proximity to settlements, (2) whether pine marten's distribution was associated with the co-occurrence of humans and domestic cats, and, if so, (3) whether these co-occurrence patterns were associated with proximity to anthropogenic infrastructures. Additionally, we explored similarities in activity patterns between pine marten and the other two species. We collected camera-trap data at 77 locations throughout Elba Island in February–July 2020. Using single-season multistate occupancy models, we found evidence that pine martens' occupancy was generally high across all vegetation types and elevation, and proximity to settlements was only weakly associated with the species occurrence. Contrary to expectations, we found no evidence of an association between pine martens' distribution and the presence of either humans or free-roaming domestic cats on Elba Island. Opposing activity patterns might have facilitated pine martens' co-existence with humans, with pine martens being active at ground level almost exclusively during nighttime. On the contrary, cats and pine martens showed similar activity patterns, and further studies are needed to define the co-existence mechanisms. These findings have important management implications and suggest that response to direct and indirect anthropogenic pressures can be highly context-dependent and mediated by the availability of resources and competition mechanisms.