Opportunity and peril: how wolves use a dense network of forest roads

The presence of wolves leads to spatial differentiation in deer browsing pressure on forest regeneration

With the recent return of large carnivores to forest ecosystems, an important issue for forest owners and managers is how large predators influence the behaviour of their natural prey and, consequently, cervid browsing pressure on forest regeneration. To investigate this issue, we analysed deer pressure on Scots pine and European beech plantations in northern Poland's ecosystems with and without permanent wolf populations. Two characteristics were used to describe deer browsing patterns in plantations: distance from the forest edge (spatial pattern of browsing) and number of saplings browsed (browsing intensity). Beech saplings were more intensively browsed by deer compared to pine saplings. In a forest ecosystem not inhabited by wolves, spatial variation in browsing patterns on small-sized beech plantations was the same between the edge and the center. In contrast, browsing pressure by deer was greater at the edges on large-sized pine plantations. The presence of wolves reduced deer browsing on beech and increased browsing on pine saplings. In addition, deer foraging behaviour changed in large-sized pine plantations, and browsing pressure increased only in the central areas of the plantations. We assume that the presence of wolves in a forest landscape is an important factor that alters browsing pressure on the youngest stands and their spatial pattern, and that this may be a major factor in stand regeneration, especially in small forest patches.

Logging, linear features, and human infrastructure shape the spatial dynamics of wolf predation on an ungulate neonate

Humans are increasingly recognized as important players in predator-prey dynamics by modifying landscapes. This trend has been well-documented for large mammal communities in North American boreal forests: logging creates early seral forests that benefit ungulates such as white-tailed deer (Odocoileus virginianus), while the combination of infrastructure development and resource extraction practices generate linear features that allow predators such as wolves (Canis lupus) to travel and forage more efficiently throughout the landscape. Disturbances from recreational activities and residential development are other major sources of human activity in boreal ecosystems that may further alter wolf-ungulate dynamics. Here, we evaluate the influence that several major types of anthropogenic landscape modifications (timber harvest, linear features, and residential infrastructure) have on where and how wolves hunt ungulate neonates in a southern boreal forest ecosystem in Minnesota, USA. We demonstrate that each major anthropogenic disturbance significantly influences wolf predation of white-tailed deer fawns (n = 427 kill sites). In contrast with the "human shield hypothesis" that posits prey use human-modified areas as refuge, wolves killed fawns closer to residential buildings than expected based on spatial availability. Fawns were also killed within recently-logged areas more than expected. Concealment cover was higher at kill sites than random sites, suggesting wolves use senses other than vision, probably olfaction, to detect hidden fawns. Wolves showed strong selection for hunting along linear features, and kill sites were also closer to linear features than expected. We hypothesize that linear features facilitated wolf predation on fawns by allowing wolves to travel efficiently among high-quality prey patches (recently logged areas, near buildings), and also increase encounter rates with olfactory cues that allow them to detect hidden fawns. These findings provide novel insight into the strategies predators use to hunt ungulate neonates and the many ways human activity alters wolf-ungulate neonate predator-prey dynamics, which have remained elusive due to the challenges of locating sites where predators kill small prey. Our research has important management and conservation implications for wolf-ungulate systems subjected to anthropogenic pressures, particularly as the range of overlap between wolves and deer expands and appears to be altering food web dynamics in boreal ecosystems.

A phenology of fear: Investigating scale and seasonality in predator-prey games between wolves and white-tailed deer

Predators and prey engage in games where each player must counter the moves of the other, and these games include multiple phases operating at different spatiotemporal scales. Recent work has highlighted potential issues related to scale-sensitive inferences in predator-prey interactions, and there is growing appreciation that these may exhibit pronounced but predictable dynamics. Motivated by previous assertions about effects arising from foraging games between white-tailed deer and canid predators (coyotes and wolves), we used a large and year-round network of trail cameras to characterize deer and predator foraging games, with a particular focus on clarifying its temporal scale and seasonal variation. Linear features were strongly associated with predator detection rates, suggesting these play a central role in canid foraging tactics by expediting movement. Consistent with expectations for prey contending with highly mobile predators, deer responses were more sensitive to proximal risk metrics at finer spatiotemporal scales, suggesting that coarser but more commonly used scales of analysis may miss useful insights into prey risk-response. Time allocation appears to be a key tactic for deer risk management and was more strongly moderated by factors associated with forage or evasion heterogeneity (forest cover, snow and plant phenology) than factors associated with the likelihood of predator encounter (linear features). Trade-offs between food and safety appeared to vary as much seasonally as spatially, with snow and vegetation phenology giving rise to a "phenology of fear." Deer appear free to counter predators during milder times of year, but a combination of poor foraging state, reduced forage availability, greater movements costs, and reproductive state dampen responsiveness during winter. Pronounced intra-annual variation in predator-prey interactions may be common in seasonal environments.

Quantifying anthropogenic wolf mortality in relation to hunting regulations and landscape attributes across North America

Understanding the types and magnitude of human‐caused mortality is essential for maintaining viable large carnivore populations. We used a database of cause‐specific mortality to examine how hunting regulations and landscape configurations influenced human‐caused mortality of North American gray wolves (Canis lupus). Our dataset included 21 studies that monitored the fates of 3564 wolves and reported 1442 mortalities. Human‐caused mortality accounted for 61% of mortality overall, with 23% due to illegal harvest, 16% due to legal harvest, and 12% the result of management removal. The overall proportion of anthropogenic wolf mortality was lowest in areas with an open hunting season compared to areas with a closed hunting season or mixed hunting regulations, suggesting that harvest mortality was neither fully additive nor compensatory. Proportion of mortality from management removal was reduced in areas with an open hunting season, suggesting that legal harvest may reduce human‐wolf conflicts or alternatively that areas with legal harvest have less potential for management removals (e.g., less livestock depredation). Proportion of natural habitat was negatively correlated with the proportion of anthropogenic and illegal harvest mortality. Additionally, the proportion of mortality due to illegal harvest increased with greater natural habitat fragmentation. The observed association between large patches of natural habitat and reductions in several sources of anthropogenic wolf mortality reiterate the importance of habitat preservation to maintain wolf populations. Furthermore, effective management of wolf populations via implementation of harvest may reduce conflict with humans. Effective wolf conservation will depend on holistic strategies that integrate ecological and socioeconomic factors to facilitate their long‐term coexistence with humans.

Wolf Responses to Experimental Human Approaches Using High-Resolution Positioning Data

Humans pose a major mortality risk to wolves. Hence, similar to how prey respond to predators, wolves can be expected to show anti-predator responses to humans. When exposed to a threat, animals may show a fight, flight, freeze or hide response. The type of response and the circumstances (e.g., distance and speed) at which the animal flees are useful parameters to describe the responses of wild animals to approaching humans. Increasing knowledge about behavioral responses of wolves toward humans might improve appropriate management and decrease conflicts related to fear of wolves. We did a pilot study by conducting 21 approach trials on seven GPS-collared wolves in four territories to investigate their responses to experimental human approaches. We found that wolves predominantly showed a flight response (N = 18), in a few cases the wolf did not flee (N = 3), but no wolves were seen or heard during trials. When wolves were downwind of the observer the flight initiation distance was significantly larger than when upwind, consistent with the hypothesis that conditions facilitating early detection would result in an earlier flight. Our hypothesis that early detection would result in less intense flights was not supported, as we found no correlation between flight initiation distances and speed, distance or straightness of the flight. Wolves in more concealed habitat had a shorter flight initiation distance or did not flee at all, suggesting that perceived risk might have been affected by horizontal visibility. Contrary to our expectation, resettling positions were less concealed (larger horizontal visibility) than the wolves’ initial site. Although our small number of study animals and trials does not allow for generalizations, this pilot study illustrates how standardized human approach trials with high-resolution GPS-data can be used to describe wolf responses at a local scale. In continuation, this method can be applied at larger spatial scales to compare wolf flight responses within and between populations and across anthropogenic gradients, thus increasing the knowledge of wolf behavior toward humans, and potentially improving coexistence with wolves across their range.

Who Uses Forest Roads? Has the COVID-19 Pandemics Affected Their Recreational Usage? Case Study from Central Slovakia

Forest roads are necessary to provide access to forests and are also used by users other than forest owners and the timber industry. Their usage for recreation and hiking has been increasing in the last years. From 1/2020 to 12/2020, we performed research on traffic loads and the use of forest roads at an area of the University Forest Enterprise of Technical University in Zvolen. For this purpose, we selected two localities, namely Včelien = A locality and Štagiar = B locality. We monitored transport intensity at selected localities with images obtained from two identical Trail Spromise S308 cameras. We examined the impact of lockdown periods during the COVID-19 pandemics on forest recreation in the year 2020 with the Kruskal–Wallis ANOVA. Multiple comparisons of p values showed there were no differences in the recreational usage of forest roads between the lockdown periods and periods without restrictions. We found that recreation activities peaked in summer and spring. Recreation and transport at selected localities did not have a negative impact on animal occurrence, as the regression and correlation analysis revealed only a low negative relationship with r = 0.029. When considering the number of passages, roads were used for recreation and other non-forestry purposes at approximately 36%. From the perspective of the weight load, recreation accounted for about 10%.

Wolves make roadways safer, generating large economic returns to predator conservation

Recent studies uncover cascading ecological effects resulting from removing and reintroducing predators into a landscape, but little is known about effects on human lives and property. We quantify the effects of restoring wolf populations by evaluating their influence on deer-vehicle collisions (DVCs) in Wisconsin. We show that, for the average county, wolf entry reduced DVCs by 24%, yielding an economic benefit that is 63 times greater than the costs of verified wolf predation on livestock. Most of the reduction is due to a behavioral response of deer to wolves rather than through a deer population decline from wolf predation. This finding supports ecological research emphasizing the role of predators in creating a "landscape of fear." It suggests wolves control economic damages from overabundant deer in ways that human deer hunters cannot.

Factors affecting deer pressure on forest regeneration: The roles of forest roads, visibility and forage availability

BACKGROUND

Deer pressure on forest regeneration constitutes a serious problem in commercial forests in the northern hemisphere due to the increase in deer populations. However, other drivers, such as climate, landscape structure and the level of human activity, have a strong influence on deer pressure. The direct, density-related impacts of ungulates on forest regeneration have been well studied, but there is limited empirical evidence related to the indirect factors mentioned above. We conducted a field experiment in three forest divisions in Poland to evaluate the role of a common element of human infrastructure, i.e. small, unpaved forestry roads. Additionally, we assessed the modifying effect of visibility driven by vegetation cover and forage availability.

RESULTS

The proximity of unpaved roads affected deer habitat use and foraging behaviour, and limited browsing pressure on regenerating forests. Low visibility and higher winter forage availability increased the probability of tree browsing. We observed different responses to roads in two deer species: red deer avoided roads, while roe deer browsed in the vicinity of roads.

CONCLUSIONS

A typical forest network of unpaved roads creates a landscape of fear for red and roe deer, and limits browsing pressure on regenerating forests due to the changes in deer habitat use, activity patterns and foraging behaviour. Knowledge of the factors influencing browsing pressure can help to spatially optimise the application of protective measures for tree seedlings.

Communication hubs of an asocial cat are the source of a human-carnivore conflict and key to its solution

The cheetah is a prominent example for human–carnivore conflicts and mitigation challenges. Its global population suffered a substantial decline throughout its range. Here, we present an in-depth and new understanding of the socio-spatial organization of the cheetah. We show that cheetahs maintain a network of communication hubs distributed in a regular pattern across the landscape, not contiguous with each other and separated by a surrounding matrix. Cheetahs spend a substantial amount of their time in these hubs, resulting in high local cheetah activity, which represents a high local predation risk for livestock. Implementing this knowledge, farmers were able to reduce livestock losses by 86%.

Human–wildlife conflicts occur worldwide. Although many nonlethal mitigation solutions are available, they rarely use the behavioral ecology of the conflict species to derive effective and long-lasting solutions. Here, we use a long-term study with 106 GPS-collared free-ranging cheetahs (Acinonyx jubatus) to demonstrate how new insights into the socio-spatial organization of this species provide the key for such a solution. GPS-collared territory holders marked and defended communication hubs (CHs) in the core area of their territories. The CHs/territories were distributed in a regular pattern across the landscape such that they were not contiguous with each other but separated by a surrounding matrix. They were kept in this way by successive territory holders, thus maintaining this overdispersed distribution. The CHs were also visited by nonterritorial cheetah males and females for information exchange, thus forming hotspots of cheetah activity and presence. We hypothesized that the CHs pose an increased predation risk to young calves for cattle farmers in Namibia. In an experimental approach, farmers shifted cattle herds away from the CHs during the calving season. This drastically reduced their calf losses by cheetahs because cheetahs did not follow the herds but instead preyed on naturally occurring local wildlife prey in the CHs. This implies that in the cheetah system, there are “problem areas,” the CHs, rather than “problem individuals.” The incorporation of the behavioral ecology of conflict species opens promising areas to search for solutions in other conflict species with nonhomogenous space use.

Landscape Connectivity and Suitable Habitat Analysis for Wolves (Canis lupus L.) in the Eastern Pyrenees

Over the last few decades, much of the mountain area in European countries has turned into potential habitat for species of medium- and large-sized mammals. Some of the occurrences that explain this trend are biodiversity protection, the creation of natural protected areas, and the abandonment of traditional agricultural activities. In recent years, wolves have once again been seen in forests in the eastern sector of the Pyrenees and the Pre-Pyrenees. The success or failure of their permanent settlement will depend on several factors, including conservation measures for the species, habitat availability, and the state of landscape connectivity. The aim of this study is to analyze the state of landscape connectivity for fragments of potential wolf habitat in Catalonia, Andorra, and on the French side of the Eastern Pyrenees. The results show that a third of the area studied constitutes potential wolf habitat and almost 90% of these spaces are of sufficient size to host stable packs. The set of potential wolf habitat fragments was also assessed using the probability of connectivity index (dPC), which analyses landscape connectivity based on graph structures. According to the graph theory, the results confirm that all the nodes or habitat fragments are directly or indirectly interconnected, thus forming a single component. Given the large availability of suitable habitat and the current state of landscape connectivity for the species, the dispersal of the wolf would be favorable if stable packs are formed. A new established population in the Pyrenees could lead to more genetic exchange between the Iberian wolf population and the rest of Europe’s wolf populations.

Scent marking in wolves Canis lupus inhabiting managed lowland forests in Poland

In wolves Canis lupus, scent marking plays an important role in territory defence. In Europe, studies on patterns of scent marking in wolves have mostly been conducted in mountains or primeval forests, but since these areas are characterised by low human activity, the impact of people on this behaviour has been neglected. We conducted a study that combined genetic methods with an analysis of the spatial distribution of wolf territory markings in lowland managed forests with high human activity. We found that scent markings are deposited by all members of wolf family groups. Wolves most intensively marked crossroads and their vicinity, especially on roads only accessible for four-wheel drive cars. Our study provides further evidence that crossroads of forest roads play a crucial role in wolf scent marking. The results of our study may be useful during inventories of wolf populations based on collecting indirect signs of their presence or non-invasive genetic sampling.