Wolf predation on wild ungulates: how slope and habitat cover influence the localization of kill sites

Abstract

Based on data collected along the Ligurian Apennines and Alps (N-W Italy), we analysed the main environmental and human-related factors influencing the distribution of kill sites of the wolf Canis lupus. We mapped and digitized 62 kill sites collected during 2007–2016. Around each kill site, we defined a buffer corresponding to the potential hunting area of wolves. We compared kill site plots and an equal number of random plots. We formulated a model of kill site distribution following an approach presence versus availability by binary logistic regression analysis; we tested the hypothesis that wolf choice of kill sites is influenced by the physiography and the land use of the area. Among the preyed wild ungulates, we identified 23 roe deer Capreolus capreolus, 18 fallow deer Dama dama, 16 wild boars Sus scrofa, and 5 chamois Rupicapra rupicapra. Binary logistic regression analysis showed a negative effect of the road density, the urban areas, the mixed forests, and a positive effect of steep slopes and open habitats. Prey are more vulnerable to predators under certain conditions and predators are capable of selecting for these conditions. Wolves achieved this by selecting particular habitats in which to kill their prey: they preferred steep, open habitats far from human presence, where wild ungulates are more easily detectable and chasable.

Anthropogenic and Environmental Factors Determining Local Favourable Conditions for Wolves during the Cold Season

“…In agreement with our results, previous works [50,53] have reported that, in dense forest cover, wild ungulates are more wary than in open areas and that this condition favours predator detection due to their noisier approach [54]; moreover, previous studies have shown that roe deer presence in the wolf diet increased with an increase in open areas [55].…”

“…Several studies have reported positive relationships between open habitats and wolf presence [61], kills, and scavenging sites [50,52,62,63], suggesting that extended open areas favour coursing behaviour, allowing wolves to engage in cooperative hunting strategies and to better choose vulnerable individuals [52,63]. Differently, in our case study, open habitats (i.e., pastures and natural grasslands) negatively affected wolf responsiveness in winter.…”

“…In agreement with our results, Harrington and Mech [1] highlighted that, during the non-rendezvous period (particularly in December-February), wolves commonly limit their reaction to vocal stimuli when kills or carrions are present at or near the response sites. Furthermore, several studies [15][16][17]50] have verified that the place where a kill occurs is affected by habitat features representing the best trade-off between prey availability and the probability of a final successful kill.…”

“…Forest cover, in particular, was reported to be a crucial driver of wolf presence, being directly associated with trophic resource availability [8]; however, the latter is only a component of the predation hierarchical process described by McPhee et al [14]. Indeed, where prey are available, the success of a hunt strongly depends, at the local scale, on habitat and landscape features that contextually favour predation strategies and hinder the escape of the prey [15][16][17][50][51][52].…”

Predicting multi-predator risk to elk (Cervus canadensis) using scats: Are migrant elk exposed to different predation risk?

“…, a risky place is one where there is a high probability of encountering and being killed by a predator. For example, elk select for areas with abundant forage biomass in summer (Hebblewhite & Merrill, 2009;Smolko 2014), which is where we found a higher probability of elk being present in the scat of all species; we also found elk being in wolf scats associated with rugged terrain, which is where Torretta et al, (2018) also reported wolf kill sites, suggesting ruggedness reduced agility to navigate in steep terrain.…”