L'occorrenza del capriolo nelle Alpi Marittime: come il disturbo antropico influenza la selezione dell'habitat

The development of infrastructure and widespread human presence in natural ecosystems for economic-recreational purposes are significantly altering habitat conditions. This anthropic disturbance impacts on wildlife, altering their biological, spatial and/or temporal behaviors. The roe deer, facing predatory risk from wolves, indirect competition with red deer and disturbance generated by human activities, has been selected as the target species for this study. The objective of the analysis is to investigate the environmental variables selected by roe deer and assess the potential influence of human activities on their habitat selection. A sampling design was applied using 79 camera-traps (CTs), each placed within 1.5 km2 grid cells. The study area, located within the Maritime Alps, encompasses two valleys in the South-Western Alps. Data collection occurred during the spring-summer season (April 1st - September 31th, 2023). The CTs were checked monthly for battery replacement and data download. Photographs were analyzed using Timelapse Image Analyzer software. An occupancy model framework was applied, aimed at testing different hypotheses on roe deer habitat selection by including (i) only environmental variables, (ii) only anthropogenic variables and (iii) an integration of the two conditions (mixed models). All data analyses were conducted on R-studio software. 6 CTs were excluded from sampling due to the absence of continuous data. The remaining 73 CTs collected data for 9937 trap days obtaining a total of 104982 pictures. Roe deer resulted to be the most widespread species in the area (90% naive occupancy), followed by humans and vehicles (61%). Regarding roe deer detection probability, the framing percentage without obstacles (CT visibility), the number of trap days per CT and the allocation away from trails revealed a significantly positive effect. Roe deer occupancy was positively influenced by the forest cover percentage, the proximity to open lands and the distance from building or pasture areas exploited by livestock. The results obtained in the study confirm the relevance of woodland cover for sheltering functions and the preference of ecotonal habitats for the presence of highly nutritional plant species. Light and sound disturbance and the increased vehicles movement in the surroundings of buildings cause the roe deer to avoid urban centers. Indirect competition between livestock and roe deer could be determined by the reduction of the food resource, pastoral activities associated with the herd and the presence of guard dogs perceived by the target species as possible predators. These insights into roe deer habitat selection contribute to increase our knowledge about the species biology in anthropized Alpine environments. Such information can be valuable for environmental management authorities in order to promote the conservation of roe deer and the coexistence with human activities.