Human Altered Landscape / Road Density & Wolves

Abstract

The recent expansion of grey wolves (Canis lupus) in Italy has led them into new ecological contexts, including areas characterized by poor prey communities and landscape anthropization. While dietary studies are essential for predicting wolf’s ecological functions and impacts, it remains unclear whether research on wolf diet has kept pace with this expansion. We mapped the current distribution of wolves in Italy and then clusterized areas based on food resources available to wolves: domestic or wild ungulates, the coypu (Myocastor coypus), and resources associated with landscape anthropization. Finally, we checked the coverage of each cluster by dietary studies (n = 33). Areas currently inhabited by wolves in Italy include nine different food resource assemblages. However, most studies on wolf diet have focused on remote areas of the Alps, where northern Chamois and red deer are abundant, and in areas with a rich assemblage of wild ungulates. In contrast, wolf diet remains unexplored in Mediterranean ecosystems with poorer ungulate assemblages and in highly anthropized landscapes, despite these environments together accounting for most areas of ongoing wolf expansion. These gaps may preventing us from knowing if wolves in highly anthropized landscapes are exposed to toxic compounds and if predation on domestic pets can trigger conflicts. Similarly, the lack of research in areas where wolves rely almost exclusively on wild Boar hinders our ability to predict the potential impact of African Swine Fever on wolf ecology and behaviour, as well as its broader influence on human-wolf conflicts.

Optimizing energy acquisition and expenditure is a fundamental trade-off for consumers, strikingly reflected in how mobile organisms use space. Several studies have established that.

home range size decreases as resource density increases, but the balance of costs and benefits associated with exploiting a given resource density is unclear. We evaluate how the ability of consumers to exploit their resources through movement (termed “resource exploitation”) interacts with resource density to influence home range size. We then contrast two hypotheses to evaluate how resource exploitation influences home range size across a vast gradient of productivity and density of human-created linear features (roads and seismic lines) that are known to facilitate animal movements. Under the Diffusion Facilitation Hypothesis, linear features are predicted to lead to more diffuse space use and larger home ranges. Under the Exploitation Efficiency Hypothesis, linear features are predicted to increase foraging efficiency, resulting in less space being required to meet energetic demands and therefore smaller home ranges. Using GPS telemetry data from 142 wolves (Canis lupus) distributed over more than 500,000 km2, we found that wolf home range size was influenced by the interaction between resource density and exploitation efficiency. Home range size decreased as linear feature density increased, supporting the Exploitation Efficiency Hypothesis. However, the effect of linear features on home range size diminished in more productive areas, suggesting that exploitation efficiency is of greater importance when resource density is low. These results suggest that smaller home ranges will occur where both linear feature density and primary productivity are higher, thereby increasing regional wolf density.