•The ecological role of large carnivores is a main motivator for their conservation.•Hunting can facilitate large carnivore conservation by garnering public acceptance.•But, can hunted large ...carnivores still perform as apex predators in a trophic system?•Hunting can impact the performance of large carnivores as apex predators.•We recommend that managers consider this perspective in designing conservation goals.
Large terrestrial carnivores, e.g. wolves or bears, often play a key ecological role from their position at the apex of trophic systems. Changes to their populations reverberate through ecological communities; consequently their widespread decline in numbers and shrinking distribution due to human persecution has brought about a loss and reconfiguration of biological diversity in many systems. Although many large carnivore populations are now under conservation-minded management, political and economic constraints make compromises necessary. A common compromise is to permit limited harvests, with the premise of sustainability and the objective to increase tolerance and funding for carnivore recovery and conservation. Here we question whether a large carnivore that has to “look over its shoulder” for human hunters can still fully perform its ecological role at the apex of a trophic system. We use information about carnivore behavior, ecology, trophic interactions, and the effects of human exploitation to argue that exploitation of large carnivores, even if sustainable numerically, undermines the commonly expressed rationale for their conservation, namely the restoration and preservation of ecosystem functionality. Our argument centers around (i) the necessity of behavioral adjustments in large carnivores to anthropomorphic risk, which may limit their contribution to the “landscape of fear”, and (ii) the observation that many of the same features that put large carnivores at the apex of trophic systems also make them vulnerable to human exploitation and persecution, with implicit consequences for their ecological functionality and evolution. Although hunting large carnivores can improve public acceptance, managers must be aware of the trade-offs.
The ongoing recovery of terrestrial large carnivores in North America and Europe is accompanied by intense controversy. On the one hand, reestablishment of large carnivores entails a recovery of ...their most important ecological role, predation. On the other hand, societies are struggling to relearn how to live with apex predators that kill livestock, compete for game species, and occasionally injure or kill people. Those responsible for managing these species and mitigating conflict often lack fundamental information due to a long-standing challenge in ecology: How do we draw robust population-level inferences for elusive animals spread over immense areas? Here we showcase the application of an effective tool for spatially explicit tracking and forecasting of wildlife population dynamics at scales that are relevant to management and conservation. We analyzed the world’s largest dataset on carnivores comprising more than 35,000 noninvasively obtained DNA samples from over 6,000 individual brown bears (Ursus arctos), gray wolves (Canis lupus), and wolverines (Gulo gulo). Our analyses took into account that not all individuals are detected and, even if detected, their fates are not always known. We show unequivocal quantitative evidence of large carnivore recovery in northern Europe, juxtaposed with the finding that humans are the single-most important factor driving the dynamics of these apex predators. We present maps and forecasts of the spatiotemporal dynamics of large carnivore populations, transcending national boundaries and management regimes.
Large carnivores inhabiting human-dominated landscapes often interact with people and their properties, leading to conflict scenarios that can mislead carnivore management and, ultimately, jeopardize ...conservation. In northwest Spain, brown bears Ursus arctos are strictly protected, whereas sympatric wolves Canis lupus are subject to lethal control. We explored ecological, economic and societal components of conflict scenarios involving large carnivores and damages to human properties. We analyzed the relation between complaints of depredations by bears and wolves on beehives and livestock, respectively, and bear and wolf abundance, livestock heads, number of culled wolves, amount of paid compensations, and media coverage. We also evaluated the efficiency of wolf culling to reduce depredations on livestock. Bear damages to beehives correlated positively to the number of female bears with cubs of the year. Complaints of wolf predation on livestock were unrelated to livestock numbers; instead, they correlated positively to the number of wild ungulates harvested during the previous season, the number of wolf packs, and to wolves culled during the previous season. Compensations for wolf complaints were fivefold higher than for bears, but media coverage of wolf damages was thirtyfold higher. Media coverage of wolf damages was unrelated to the actual costs of wolf damages, but the amount of news correlated positively to wolf culling. However, wolf culling was followed by an increase in compensated damages. Our results show that culling of the wolf population failed in its goal of reducing damages, and suggest that management decisions are at least partly mediated by press coverage. We suggest that our results provide insight to similar scenarios, where several species of large carnivores share the landscape with humans, and management may be reactive to perceived conflicts.
Globally, climate is changing rapidly, which causes shifts in many species' distributions, stressing the need to understand their response to changing environmental conditions to inform conservation ...and management. Northern latitudes are expected to experience strongest changes in climate, with milder winters and decreasing snow cover. The wolverine (Gulo gulo) is a circumpolar, threatened carnivore distributed in northern tundra, boreal, and subboreal habitats. Previous studies have suggested that wolverine distribution and reproduction are constrained by a strong association with persistent spring snow cover. We assess this hypothesis by relating spatial distribution of 1589 reproductive events, a fitness-related proxy for female reproduction and survival, to snow cover over two decades. Wolverine distribution has increased and number of reproductive events increased 20 times in areas lacking spring snow cover during our study period, despite low monitoring effort where snow is sparse. Thus, the relationship between reproductive events and persistent spring snow cover weakened during this period. These findings show that wolverine reproductive success and hence distribution are less dependent on spring snow cover than expected. This has important implications for projections of future habitat availability, and thus distribution, of this threatened species. Our study also illustrates how past persecution, or other factors, that have restricted species distribution to remote areas can mask actual effects of environmental parameters, whose importance reveals when populations expand beyond previously restricted ranges. Overwhelming evidence shows that climate change is affecting many species and ecological processes, but forecasting potential consequences on a given species requires longitudinal data to revisit hypotheses and reassess the direction and magnitude of climate effects with new data. This is especially important for conservation-oriented management of species inhabiting dynamic systems where environmental factors and human activities interact, a common scenario for many species in different ecosystems around the globe.
Prey usually adjust anti-predator behavior to subtle variations in perceived risk. However, it is not clear whether adult large carnivores that are virtually free of natural predation adjust their ...behavior to subtle variations in human-derived risk, even when living in human-dominated landscapes. As a model, we studied resting-site selection by a large carnivore, the brown bear (Ursus arctos), under different spatial and temporal levels of human activity. We quantified horizontal and canopy cover at 440 bear beds and 439 random sites at different distances from human settlements, seasons, and times of the day. We hypothesized that beds would be more concealed than random sites and that beds would be more concealed in relation to human-derived risk. Although human densities in Scandinavia are the lowest within bear ranges in Western Europe, we found an effect of human activity; bears chose beds with higher horizontal and canopy cover during the day (0700–1900 hours), especially when resting closer to human settlements, than at night (2200–0600 hours). In summer/fall (the berry season), with more intensive and dispersed human activity, including hunting, bears rested further from human settlements during the day than in spring (pre-berry season). Additionally, day beds in the summer/fall were the most concealed. Large carnivores often avoid humans at a landscape scale, but total avoidance in human-dominated areas is not possible. Apparently, bears adjust their behavior to avoid human encounters, which resembles the way prey avoid their predators. Bears responded to fine-scale variations in human-derived risk, both on a seasonal and a daily basis.
Expansion of human activities into large carnivore habitats and of large carnivore ranges into anthropogenic settings increase the potential for human-wildlife conflicts. Future carnivore survival ...and recovery depend on both their ability to adapt to human-modified landscapes and the application of adequate conservation strategies. We review human-related factors that negatively affect brown bears inhabiting human-modified landscapes, aiming to improve human-bear coexistence. Brown bears have triggered much research and a review on this model species should be useful for the conservation-oriented management of many large carnivores. In human-modified landscapes, main threats to bear populations are human settlements, habituation and availability of anthropogenic food, density and traffic load of roads and railways, and recreational and industrial activities. Main effects of coexistence with humans for bears are: increased disturbance, human-bear conflicts and human-caused mortality; behavioural alterations; reduced fitness and genetic diversity; and physiological alterations. To promote bear-human coexistence in human-modified landscapes, we identified nine key elements: reduction of human-induced mortality and use of scientific information for better assessment of new infrastructures; improve education on waste management and bear deterrence methods; safeguard and restore habitat connectivity; mitigate road effects and restrict motorized trail use; adjust viewing activity practices to local conservation status of bear populations and food availability; implement mitigation measures to minimize risk of human-bear encounters; quantify empirically the effects of recreational activities on the energetics and fitness of bears; better dissemination of scientific results and management guidelines; and further research on behavioural reactions of bears to different management regimes and persecution histories.
•Human expansion into bear ranges and viceversa can cause human-wildlife conflict.•Human activities cause multiple negative effects on brown bears worldwide.•Human-caused disturbance and mortality occur all around the globe.•Detected effects of human-bear coexistence should enlighten conservation strategies.•Conservation strategies must adapt locally to large carnivore population dynamics.
The recovery of large carnivores in human-dominated landscapes comes with challenges. In general, large carnivores avoid humans and their activities, and human avoidance favors coexistence, but ...individual variation in large carnivore behavior may occur. The detection of individuals close to human settlements or roads can trigger fear in local communities and in turn demand management actions. Understanding the sources of individual variation in carnivore behavior towards human features is relevant and timely for ecology and conservation. We studied the movement behavior of 52 adult established wolves ((Canis lupus), 44 wolf pairs) with GPS-collars over two decades in Scandinavia in relation to settlements, buildings, and roads. We fit fine-scale movement data to individual step selection functions to depict the movement decisions of wolves while travelling, and then used weighted linear mixed models to identify factors associated with potential individual pair deviations from the general behavioral patterns. Wolves consistently avoided human settlements and main roads, with little individual variation. Indeed, after correcting for season, time of the day, and latitude, there was little variability in habitat selection among wolf pairs, demonstrating that all wolf pairs had similar movement pattern and generally avoided human features of the landscape. Wolf avoidance of human features was lower at higher latitudes particularly in winter, likely due to seasonal prey migration. Although occasional sightings of carnivores or their tracks near human features do occur, they do not necessarily require management intervention. Communication of scientific findings on carnivore behavior to the public should suffice in most cases.
•Many large carnivores show behavioral plasticity in their daily movement patterns.•Whether environmental or anthropogenic cues cause such variation is not clear yet.•Brown bears moved more in the ...nocturnal and twilight hours in areas with higher road density.•Human proximity, a proxy of human density around bears, had no effect on their behavior.•Minimizing disturbance on carnivore behavior should be included in management plans.
Large carnivores adjust their daily movement patterns in response to environmental factors and/or human disturbance, and often respond differently across their distribution range. Whether such behavioral plasticity is due to environmental or anthropogenic factors has not yet been fully clarified. Beyond large carnivore conservation and management, understanding behavioral changes in the movement patterns of these elusive species may prove useful to evaluate anthropogenic influences on ecosystems. We used 696 318 GPS locations from 105 radio-collared brown bears in 3 study areas in Sweden to construct daily bear movement patterns, calculating the distance traveled by the bears every 30min. We used a Bayesian approach to analyze whether human and/or road density around bear locations could explain observed differences in bear movement patterns among the areas. Proximity to settlements, a proxy of the generally low human density in Scandinavian bear range, did not influence circadian bear movements. However, bears moved most in the nocturnal and twilight hours and less during daytime in areas with higher road density, compared to roadless areas. Human-caused behavioral changes in large carnivores may have potential ecosystem-level consequences, given the key ecological role that these species can play in ecosystems. Limiting the creation and use of roads is necessary to maintain large carnivore distribution ranges and movement corridors, reduce human-caused mortality, and minimize human-induced disturbance that modifies carnivore behavior.
The rather limited human ability to understand animal vision and visual signalling has frequently clouded our expectations concerning the visual abilities of other animals. But there are multiple ...reasons to suspect that visual signalling is more widely employed by animals than previously thought. Because visibility of visual marks depends on the background in which they are seen, species spending most of their time living in dark conditions (e.g., in forests and/or having crepuscular and nocturnal habits) may rely on bright signals to enhance visual display. Here, as a result of experimental manipulations, we present, for the first time ever, evidence supporting the use of a new channel of intraspecific communication by a mammal species, i.e., brown bear Ursus arctos adult males relying on visual marks during mating. Bear reactions to our manipulation suggest that visual signalling could represent a widely overlooked mechanism in mammal communication, which may be more broadly employed than was previously thought.
Evolutionary traps, and their derivative, ecological traps, occur when animals make maladaptive decisions based on seemingly reliable environmental cues, and are important mechanistic explanations ...for declines in animal populations.
Despite the interest in large carnivore conservation in human‐modified landscapes, the emergence of traps and their potential effects on the conservation of large carnivore populations has frequently been overlooked.
The brown bear Ursus arctos typifies the challenges facing large carnivore conservation and recent research has reported that this species can show maladaptive behaviours in human‐modified landscapes. Here we review, describe and discuss scenarios recognised as evolutionary or ecological traps for brown bears, and propose possible trap scenarios and mechanisms that have the potential to affect the dynamics and viability of brown bear populations.
Six potential trap scenarios have been detected for brown bears in human‐modified landscapes: 1) food resources close to human settlements; 2) agricultural landscapes; 3) roads; 4) artificial feeding sites; 5) hunting by humans; and 6) other human activities. Because these traps are likely to be of contrasting relevance for different demographic segments of bear populations, we highlight the importance of evaluations of the relative demographic consequences of different trap types for wildlife management. We also suggest that traps may be behind the decreases in brown bear and other large carnivore populations in human‐modified landscapes.
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