Evidence of wolf dispersal in anthropogenic habitats of the Polish Carpathian Mountains

In the course of their maturation, most young wolves leave their natal pack and disperse in search for mating partners, improved food availability and new territories. We investigated whether this dispersal is affected by anthropogenic infrastructure in a 5,000 km2 area of the eastern region of the Polish Carpathian Mountains occupied by wolves. A radio-collared male wolf covered 230 km while dispersing through forested hills and densely populated valleys. To test if such dispersal is common in the population we analysed by microsatellite genotyping 39 samples taken from live-trapped wolves or wolves found dead in the study area. Although the obtained genotypes were assigned to different clusters in Bayesian tests, we could not ascribe this structure to landscape features, but rather to shared ancestry of wolf individuals found in distant locations. Moreover, we could not detect a spatial genetic structure in the wolf population, indicating a random occurrence of genotypes within the study area. Observation of the dispersing wolf and the absence of spatial genetic structure imply that wolves are still able to roam the entire area despite high densities of roads and a dense human population. Thus, we concluded that the existing anthropogenic infrastructure does not restrict wolf dispersal in the area and the studied wolves represent a coherent part of the Polish Carpathian wolf population.     

Interacting effect of wolves and climate on recruitment in a northern mountain caribou population

There is limited research on the influence of Pacific‐based climate in large herbivore populations. Additionally, much of our understanding on the effect of large‐scale climate on ungulate population dynamics has occurred on forage‐limited rather than predator‐limited populations. We compared the influence of the Pacific Decadal Oscillation (PDO), North Pacific Index, and local weather on recruitment in a predator‐limited mountain‐dwelling caribou Rangifer tarandus caribou population in the Yukon Territory, Canada, across a range of wolf Canis lupus densities. A large‐scale wolf removal program allowed us to examine the role of Pacific climate and weather when wolves were reduced to ～15% of their pre‐removal levels. Recruitment was best explained by the interaction of wolf density and April‐PDO, with wolf density explaining the most deviance. Predicted recruitment during good springs was 0.45 (SE = 0.04) during wolf removal and 0.29 (SE = 0.03) with no wolf removal. During poor springs (low PDO, increased snow depth) predicted recruitment was 0.55 (SE = 0.10) during wolf removal and 0.12 (SE = 0.03) with no wolf removal. With non‐altered wolf densities, there was a positive relationship between April‐PDO and recruitment due to reduced snow depth at calving, allowing parturient females to disperse up in elevation away from predators. When wolf densities were substantially reduced there was a slight negative relationship between April‐PDO and recruitment, possibly due to a more rapid vegetation green‐up reducing the temporal availability of highly nutritious forage necessary for lactation and subsequent calf growth. Attempts to find general relationships between climate and ungulate population dynamics have proven difficult due to different ecological mechanisms by which climate affects individuals across populations. Temporally varying factors, such as predator density, may also play an important role in uncovering the mechanistic relationship between climate and population dynamics.     

The forgotten prey of an iconic predator: a review of interactions between grey wolves Canis lupus and beavers Castor spp.

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Dispersal Behavior and the Connectivity Between Wolf Populations in Northern Europe

ABSTRACT The isolated gray wolf (Canis lupus) population of the Scandinavian Peninsular is suffering from inbreeding depression. We studied dispersal of 35 wolves fitted with very high frequency (20) or Global Positioning System—global system for mobile (15) radiocollars in the neighboring Finnish wolf population. The growing wolf population in Finland has high numbers of dispersing individuals that could potentially disperse into the Scandinavian population. About half (53%) of the dispersing wolves moved total distances that could have reached the Scandinavian population if they had been straight-line moves, but because of the irregular pattern of movements, we detected no wolves successfully dispersing to the Scandinavian population. Dispersal to the Scandinavian population was also limited by high mortality of wolves in reindeer (Rangifer tarandus) management areas and by dispersal to Bothnian Bay at times of the year when ice was not present. We suggest that when a small wolf population is separated from source populations by distance, barriers, and human exploitation, wildlife managers could promote the population's viability by limiting harvest in the peripheral areas or by introducing wolves from the source population.     

Optimal predator management for mountain sheep conservation depends on the strength of mesopredator release

Large predators often suppress ungulate population growth, but they may also suppress the abundance of smaller predators that prey on neonatal ungulates. Antagonistic interactions among predators may therefore need to be integrated into predator–prey models to effectively manage ungulate–predator systems. We present a modeling framework that examines the net impact of interacting predators on the population growth rate of shared prey, using interactions among wolves Canis lupus, coyotes Canis latrans and Dall sheep Ovis dalli dalli as a case study. Wolf control is currently employed on approximately 16 million ha in Alaska to increase the abundance of ungulates for human harvest. We hypothesized that the positive effects of wolf control on Dall sheep population growth could be counteracted by increased levels of predation by coyotes. Coyotes and Dall sheep adult females (ewes) and lambs were radiocollared in the Alaska Range from 1999–2005 to estimate fecundity, age‐specific survival rates, and causes of mortality in an area without wolf control. We used stage‐structured population models to simulate the net effect of wolf control on Dall sheep population growth (λ). Our models accounted for stage‐specific predation rates by wolves and coyotes, compensatory mortality, and the potential release of coyote populations due to wolf control. Wolves were the main predators of ewes, coyotes were the main predators of lambs, and wolves were the main source of mortality for coyotes. Population models predicted that wolf control could increase sheep λ by 4% per year in the absence of mesopredator release. However, if wolf control released coyote populations, our models predicted that sheep λ could decrease by up to 3% per year. These results highlight the importance of integrating antagonistic interactions among predators into predator–prey models, because the net effect of predator management on shared prey can depend critically on the strength of mesopredator release.     

Wolves,white‐tailed deer,and beaver: implications of seasonal prey switching for woodland caribou declines

Population increases of primary prey can negatively impact alternate prey populations via demographic and behavioural responses of a shared predator through apparent competition. Seasonal variation in prey selection patterns by predators also can affect secondary and incidental prey by reducing spatial separation. Global warming and landscape changes in Alberta's bitumen sands have resulted in prey enrichment, which is changing the large mammal predator–prey system and causing declines in woodland caribou Rangifer tarandus caribou populations. We assessed seasonal patterns of prey use and spatial selection by wolves Canis lupus in two woodland caribou ranges in northeastern Alberta, Canada, that have undergone prey enrichment following recent white‐tailed deer Odocoileus virginianus invasion. We determined whether risk of predation for caribou (incidental prey) and the proportion of wolf‐caused‐caribou mortalities varied with season. We found that wolves showed seasonal variation in primary prey use, with deer and beaver Castor canadensis being the most common prey items in wolf diet in winter and summer, respectively. These seasonal dietary patterns were reflected in seasonal wolf spatial resource selection and resulted in contrasting spatial relationships between wolves and caribou. During winter, wolf selection for areas used by deer maintained strong spatial separation between wolves and caribou, whereas wolf selection for areas used by beaver in summer increased the overlap with caribou. Changing patterns in wolf resource selection were reflected by caribou mortality patterns, with 76.2% of 42 adult female caribou mortalities occurring in summer. Understanding seasonal patterns of predation following prey enrichment in a multiprey system is essential when assessing the effect of predation on an incidental prey species. Our results support the conclusion that wolves are proximately responsible for woodland caribou population declines throughout much of their range.     

Evidence for top predator control of a grazing ecosystem

The importance of top predators in controlling ecological processes in large, intact ecosystems is unclear. In grasslands that support abundant ungulates, top–down control by predators may be particularly important, because of the tight biogeochemical linkages of ungulate prey with plants and soil microbes. Here, I examined the effects of the recent reintroduction of the gray wolf Canis lupus on ecosystem processes in Yellowstone National Park, where herds of grazing ungulates previously have been shown to stimulate several processes, including soil net nitrogen (N) mineralization. Rates of ungulate grazing intensity and soil net N mineralization were compared before and after wolf reintroduction in grasslands ranging five‐fold in aboveground production. Grazing intensity and grassland net N mineralization declined after wolf reintroduction, a likely partial function of fewer ungulates; wolf predation has been one of several factors implicated in causing the decline in Yellowstone ungulates. In addition, the spatial pattern of grazing and net N mineralization changed after reintroduction. A shift in the spatial patterns of grazer‐associated processes is consistent with a growing body of work indicating that wolves have changed habitat use patterns of ungulates in Yellowstone National Park. These findings suggest widespread wolf effects on ungulate prey, plants, and microbial activity that have spatially reorganized grassland energy and nutrient dynamics in Yellowstone Park.     

Latitude and protection affect decadal trends in reef trophic structure over a continental scale

The relative roles of top‐down (consumer‐driven) and bottom‐up (resource‐driven) forcing in exploited marine ecosystems have been much debated. Examples from a variety of marine systems of exploitation‐induced, top‐down trophic forcing have led to a general view that human‐induced predator perturbations can disrupt entire marine food webs, yet other studies that have found no such evidence provide a counterpoint. Though evidence continues to emerge, an unresolved debate exists regarding both the relative roles of top‐down versus bottom‐up forcing and the capacity of human exploitation to instigate top‐down, community‐level effects. Using time‐series data for 104 reef communities spanning tropical to temperate Australia from 1992 to 2013, we aimed to quantify relationships among long‐term trophic group population density trends, latitude, and exploitation status over a continental‐scale biogeographic range. Specifically, we amalgamated two long‐term monitoring databases of marine community dynamics to test for significant positive or negative trends in density of each of three key trophic levels (predators, herbivores, and algae) across the entire time series at each of the 104 locations. We found that trophic control tended toward bottom‐up driven in tropical systems and top‐down driven in temperate systems. Further, alternating long‐term population trends across multiple trophic levels (a method of identifying trophic cascades), presumably due to top‐down trophic forcing, occurred in roughly fifteen percent of locations where the prerequisite significant predator trends occurred. Such alternating trophic trends were significantly more likely to occur at locations with increasing predator densities over time. Within these locations, we found a marked latitudinal gradient in the prevalence of long‐term, alternating trophic group trends, from rare in the tropics (<5% of cases) to relatively common in temperate areas (~45%). Lastly, the strongest trends in predator and algal density occurred in older no‐take marine reserves; however, exploitation status did not affect the likelihood of alternating long‐term trophic group trends occurring. Our data suggest that the type and degree of trophic forcing in this system are likely related to one or more covariates of latitude, and that ecosystem resiliency to top‐down control does not universally vary in this system based on exploitation level.     

Could we live with reintroduced large carnivores in the UK?

1. Literature on the wolf Canis lupus, brown bear Ursus arctos and lynx Lynx lynx is reviewed to determine if sufficient semi‐natural habitat exists in the UK for a viable population of any of these species and to assess the potential risks to human safety, livestock and economically valuable wildlife. Public attitudes to the recovery and reintroduction of some other mammals are also briefly reviewed. 2. The large home range sizes and low population densities of large carnivores mean that the Scottish Highlands is the only UK region with the potential to support a viable population. Human population density is also lower in the Highlands and the density of wild ungulate prey higher than in many parts of Europe where large carnivores survive. 3. Attacks on people have been recorded in Europe for healthy bears and for rabid bears and wolves but there are no reports of attacks by lynx. Bears are more carnivorous in the north of their range than in the south and although wild mammals seldom appear to be important prey serious predation of livestock can occur. Livestock predation is also reported for the wolf and the lynx but they appear to prefer wild prey if available. However, mass kills of up to 100 or more sheep are occasionally recorded for wolves. 4. Attitudes to reintroductions and carnivores generally tend to be favourable amongst the general public, but negative amongst those most likely to be adversely affected. Fears for human safety and significant livestock predation with bears and wolves, respectively, suggest that reintroduction of these species is unlikely to be acceptable in the foreseeable future. Reintroduction of the lynx may be feasible but habitat suitability and potential impact on vulnerable native wildlife need to be assessed. Socio‐economic and legal issues also need to be addressed before such a reintroduction is considered.     

Reintroduced wolves and hunting limit the abundance of a subordinate apex predator in a multi-use landscape

Top-down effects of apex predators are modulated by human impacts on community composition and species abundances. Consequently, research supporting top-down effects of apex predators occurs almost entirely within protected areas rather than the multi-use landscapes dominating modern ecosystems. Here, we developed an integrated population model to disentangle the concurrent contributions of a reintroduced apex predator, the grey wolf, human hunting and prey abundances on vital rates and abundance of a subordinate apex predator, the puma. Increasing wolf numbers had strong negative effects on puma fecundity, and subadult and adult survival. Puma survival was also influenced by density dependence. Overall, puma dynamics in our multi-use landscape were more strongly influenced by top-down forces exhibited by a reintroduced apex predator, than by human hunting or bottom-up forces (prey abundance) subsidized by humans. Quantitatively, the average annual impact of human hunting on equilibrium puma abundance was equivalent to the effects of 20 wolves. Historically, wolves may have limited pumas across North America and dictated puma scarcity in systems lacking sufficient refugia to mitigate the effects of competition.     

Survival of Colonizing Wolves in the Northern Rocky Mountains of the United States, 1982–2004

Abstract: After roughly a 60-year absence, wolves (Canis lupus) immigrated (1979) and were reintroduced (1995-1996) into the northern Rocky Mountains (NRM), USA, where wolves are protected under the Endangered Species Act. The wolf recovery goal is to restore an equitably distributed metapopulation of ≥30 breeding pairs and 300 wolves in Montana, Idaho, and Wyoming, while minimizing damage to livestock; ultimately, the objective is to establish state-managed conservation programs for wolf populations in NRM. Previously, wolves were eradicated from the NRM because of excessive human killing. We used Andersen–Gill hazard models to assess biological, habitat, and anthropogenic factors contributing to current wolf mortality risk and whether federal protection was adequate to provide acceptably low hazards. We radiocollared 711 wolves in Idaho, Montana, and Wyoming (e.g., NRM region of the United States) from 1982 to 2004 and recorded 363 mortalities. Overall, annual survival rate of wolves in the recovery areas was 0.750 (95% CI = 0.728-0.772), which is generally considered adequate for wolf population sustainability and thereby allowed the NRM wolf population to increase. Contrary to our prediction, wolf mortality risk was higher in the northwest Montana (NWMT) recovery area, likely due to less abundant public land being secure wolf habitat compared to other recovery areas. In contrast, lower hazards in the Greater Yellowstone Area (GYA) and central Idaho (CID) likely were due to larger core areas that offered stronger wolf protection. We also found that wolves collared for damage management purposes (targeted sample) had substantially lower survival than those collared for monitoring purposes (representative sample) because most mortality was due to human factors (e.g., illegal take, control). This difference in survival underscores the importance of human-caused mortality in this recovering NRM population. Other factors contributing to increased mortality risk were pup and yearling age class, or dispersing status, which was related to younger age cohorts. When we included habitat variables in our analysis, we found that wolves having abundant agricultural and private land as well as livestock in their territory had higher mortality risk. Wolf survival was higher in areas with increased wolf density, implying that secure core habitat, particularly in GYA and CID, is important for wolf protection. We failed to detect changes in wolf hazards according to either gender or season. Maintaining wolves in NWMT will require greater attention to human harvest, conflict resolution, and illegal mortality than in either CID or GYA; however, if human access increases in the future in either of the latter 2 areas hazards to wolves also may increase. Indeed, because overall suitable habitat is more fragmented and the NRM has higher human access than many places where wolves roam freely and are subject to harvest (e.g., Canada and AK), monitoring of wolf vital rates, along with concomitant conservation and management strategies directed at wolves, their habitat, and humans, will be important for ensuring long-term viability of wolves in the region.     

Ecological factors drive differentiation in wolves from British Columbia

Aim Limited population structure is predicted for vagile, generalist species, such as the grey wolf (Canis lupus L.). Our aims were to study how genetic variability of grey wolves was distributed in an area comprising different habitats that lay within the potential dispersal range of an individual and to make inferences about the impact of ecology on population structure. Location British Columbia, Canada – which is characterized by a continuum of biogeoclimatic zones across which grey wolves are distributed – and adjacent areas in both Canada and Alaska, United States. Methods We obtained mitochondrial DNA control region sequences from grey wolves from across the province and integrated our genetic results with data on phenotype, behaviour and ecology (distance, habitat and prey composition). We also compared the genetic diversity and differentiation of British Columbia grey wolves with those of other North American wolf populations. Results We found strong genetic differentiation between adjacent populations of grey wolves from coastal and inland British Columbia. We show that the most likely factor explaining this differentiation is habitat discontinuity between the coastal and interior regions of British Columbia, as opposed to geographic distance or physical barriers to dispersal. We hypothesize that dispersing grey wolves select habitats similar to the one in which they were reared, and that this differentiation is maintained largely through behavioural mechanisms. Main conclusions The identification of strong genetic structure on a scale within the dispersing capabilities of an individual suggests that ecological factors are driving wolf differentiation in British Columbia. Coastal wolves are highly distinct and representative of a unique ecosystem, whereas inland British Columbia grey wolves are more similar to adjacent populations of wolves located in Alaska, Alberta and Northwest Territories. Given their unique ecological, morphological, behavioural and genetic characteristics, grey wolves of coastal British Columbia should be considered an Evolutionary Significant Unit (ESU) and, consequently, warrant special conservation status. If ecology can drive differentiation in a highly mobile generalist such as the grey wolf, ecology probably drives differentiation in many other species as well.     

Moose-wolf dynamics and the natural regulation of moose populations

Summary In southwestern Québec, non-harvested moose populations stabilize at a density of 0.40 animal·km^-2. In an attempt to test whether or not moose were regulated by predators, we investigated wolf predation near this equilibrium density (0.37) and at 2 lower densities (0.23, 0.17). Scat analysis in summer and feeding observations in winter indicated a greater use of alternative food resources by wolves at lower moose densities. Each wolf pack killed on average 5.3, 1.8, 1.1 moose·100 days in the area of 0.37, 0.23, and 0.17 moose·km^-2, respectively. Consumption of moose per wolf was 2.8, 1.7, and 1.6 kg/day, respectively. January wolf densities were estimated at 1.38, 0.82, and 0.36 animals·100 km^-2, respectively. Year-long predation rates proved to be density-dependent, increasing with moose density from 6.1 to 19.3% of the postnatal populations. We conclude that moose populations in southwestern Québec are regulated largely by predators (wolves and maybe black bears) at a density where competition for forage produces no detrimental effect. We support the concept that wolf predation can have an important regulatory effect at low moose densities but also a depensatory (inversely density-dependent) effect at higher densities.     

新疆卡拉麦里山有蹄类自然保护区冬季狼的家域

正狼(Canis lupus)是食肉目(Carnivora)、犬科(Canidae)、犬属(Canis)食肉类哺乳动物(盛和林等,1999),是世界上分布最广和研究最多的大型食肉动物(Ripple et al.,2014)。目前,我国狼的分布已由过去的全国性分布缩小至东北、西北和内蒙等地区(Zhang,1999)。在斯洛伐克,研究人员通过无线电项圈获取分布在两个国家公园内两群狼的家域利用情况(Findo and Chovancova,2004),加     

Habitat variables associated with wolf (Canis lupus) distribution and abundance in northern Poland

Based on data collected during the National Wolf Census in 2000–01, we analysed the main habitat factors influencing the distribution and abundance of the wolf, Canis lupus, in northern Poland. The study region forms the western border of the continuous Eastern European range of wolves, although attempts at westward dispersal have been observed. Using Geographic Information System techniques, we measured nine habitat variables and three parameters related to wolf occurrence in 134 circular sample plots (radius 7 km, area 154 km² each). We compared 72 plots where wolves were recorded and 62 plots with no signs of wolf presence. Wolf plots were characterized by significantly higher forest cover, less fragmentation of forests, lower density of villages, towns, motorways, and railways than wolf‐free plots. We found a positive correlation between the sum of wolf observations in plots and forest cover. The number of domestic animals killed by wolves was higher in areas with higher indices of wolf abundance and lower forest area. In multiple regression analysis, four independent variables explained 59% of the variation in wolf distribution and abundance in northern Poland: straight‐line distance to continuous range of wolves in Eastern Europe; forest cover; forest fragmentation; and length of major motorways. We conclude that protection of wolves in Poland (since 1998) may not be an adequate conservation measure, especially because of the increasing density of highways and express motorways. Existing forest corridors should be protected and new ones should be restored to ensure long‐term conservation of wolves and allow range expansion into Western Europe.     

Large‐scale patterns of seed removal by small mammals differ between areas of low‐ versus high‐wolf occupancy

Because most tree species recruit from seeds, seed predation by small‐mammal granivores may be important for determining plant distribution and regeneration in forests. Despite the importance of seed predation, large‐scale patterns of small‐mammal granivory are often highly variable and thus difficult to predict. We hypothesize distributions of apex predators can create large‐scale variation in the distribution and abundance of mesopredators that consume small mammals, creating predictable areas of high and low granivory. For example, because gray wolf (Canis lupus) territories are characterized by relatively less use by coyotes (C. latrans) and greater use by foxes (Vulpes vulpes, Urocyon cinereoargentus) that consume a greater proportion of small mammals, wolf territories may be areas of reduced small‐mammal granivory. Using large‐scale, multiyear field trials at 22 sites with high‐ and low‐wolf occupancy in northern Wisconsin, we evaluated whether removal of seeds of four tree species was lower in wolf territories. Consistent with the hypothesized consequences of wolf occupancy, seed removal of three species was more than 25% lower in high‐wolf‐occupancy areas across 2 years and small‐mammal abundance was more than 40% lower in high‐wolf areas during one of two study years. These significant results, in conjunction with evidence of seed consumption in situ and the absence of significant habitat differences between high‐ and low‐wolf areas, suggest that top‐down effects of wolves on small‐mammal granivory and seed survival may occur. Understanding how interactions among carnivores create spatial patterns in interactions among lower trophic levels may allow for more accurate predictions of large‐scale patterns in seed survival and forest composition.     

Apex predators and the facilitation of resource partitioning among mesopredators

Apex predators may influence carnivore communities through the suppression of competitively dominant mesopredators, however they also provide carrion subsidies that could influence foraging and competition among sympatric mesopredators when small prey is scarce. We assessed coyote Canis latrans and red fox Vulpes vulpes winter diet overlap and composition from scats collected in two study areas with 3‐fold difference in grey wolf Canis lupus density due to a wolf control program. We hypothesized that differences in diet composition would be driven by the use of carrion, and tested whether 1) apex predators facilitate resource overlap, or 2) apex predators facilitate resource partitioning. We estimated the available biomass of snowshoe hares and voles based on pellet density and vole capture rates in each study area. We used molecular analysis to confirm species identification of predator scats, and used microscopic evaluation of prey remains to analyze diet composition of 471 coyote and fox scats. Ungulate carrion, voles and snowshoe hares comprised 73% of coyote and fox diet, and differences in use of carrion and microtines accounted for nearly 60% of the dissimilarity in diet among these canids. Carrion was the top‐ranked item in the coyote diet in both study areas, whereas carrion use by red foxes declined 3‐fold in the study area with higher wolf and small prey abundance. Diet overlap tended to be lower and diet diversity tended to be higher where wolves were more abundant, though these trends were not statistically significant. Taken together, our findings indicate that carrion provisions could facilitate resource partitioning in mesocarnivore communities by alleviating exploitation competition for small mammals.     

Landscape of fear in Europe: wolves affect spatial patterns of ungulate browsing in Białowieża Primeval Forest,Poland

Large carnivores can either directly influence ungulate populations or indirectly affect their behaviour. Knowledge from European systems, in contrast to North American systems, on how this might lead to cascading effects on lower trophic levels is virtually absent. We studied whether wolves Canis lupus via density‐mediated and behaviorally‐mediated effects on their ungulate prey species influence patterns of browsing and tree regeneration inside the Bia?owie?a National Park, Poland. Browsing intensity of tree saplings (height class < 150 cm), irrespective of tree species or forest type, was lower inside a wolf core area (50.5%) where predator presence is highest, than in the remainder of the wolf pack’s home range (58.3%). Additionally, browsing intensity was reduced when the amount of coarse woody debris (CWD), which can act as a ?ungulate escape impediment?, increased (within 5‐m radius) inside the wolf core area. No relationship existed outside the core area. As a result, the proportion of trees growing out of herbivore control increased more strongly with increasing amount of CWD inside compared to outside the wolf core area. This suggests that next to direct effects of wolves on ungulate density caused by a higher predation pressure inside the core area, risk effects are important and are enhanced by habitat characteristics. These results indicate that behaviorally‐mediated effects of predators on prey can become more important than density‐mediated effects in affecting lower trophic levels. This is the first study we are aware of, that shows CWD can create fine‐scale risk effects on ungulates with the potential for cascading effects of large predators on patterns of tree regeneration for a European forest system. This knowledge broadens the discussion on how the impact of large predators on ecosystem functioning depends on the physical landscape, by illustrating these effects for a system which largely contrasts in this respect to the North American systems.     

Conservation of wildlife populations: factoring in incremental disturbance

Progressive anthropogenic disturbance can alter ecosystem organization potentially causing shifts from one stable state to another. This potential for ecosystem shifts must be considered when establishing targets and objectives for conservation. We ask whether a predator–prey system response to incremental anthropogenic disturbance might shift along a disturbance gradient and, if it does, whether any disturbance thresholds are evident for this system. Development of linear corridors in forested areas increases wolf predation effectiveness, while high density of development provides a safe‐haven for their prey. If wolves limit moose population growth, then wolves and moose should respond inversely to land cover disturbance. Using general linear model analysis, we test how the rate of change in moose (Alces alces) density and wolf (Canis lupus) harvest density are influenced by the rate of change in land cover and proportion of land cover disturbed within a 300,000 km² area in the boreal forest of Alberta, Canada. Using logistic regression, we test how the direction of change in moose density is influenced by measures of land cover change. In response to incremental land cover disturbance, moose declines occurred where <43% of land cover was disturbed; in such landscapes, there were high rates of increase in linear disturbance and wolf density increased. By contrast, moose increases occurred where >43% of land cover was disturbed and wolf density declined. Wolves and moose appeared to respond inversely to incremental disturbance with the balance between moose decline and wolf increase shifting at about 43% of land cover disturbed. Conservation decisions require quantification of disturbance rates and their relationships to predator–prey systems because ecosystem responses to anthropogenic disturbance shift across disturbance gradients.     

Linking anti‐predator behaviour to prey demography reveals limited risk effects of an actively hunting large carnivore

Ecological theory predicts that the diffuse risk cues generated by wide‐ranging, active predators should induce prey behavioural responses but not major, population‐ or community‐level consequences. We evaluated the non‐consumptive effects (NCEs) of an active predator, the grey wolf (Canis lupus), by simultaneously tracking wolves and the behaviour, body fat, and pregnancy of elk (Cervus elaphus), their primary prey in the Greater Yellowstone Ecosystem. When wolves approached within 1 km, elk increased their rates of movement, displacement and vigilance. Even in high‐risk areas, however, these encounters occurred only once every 9 days. Ultimately, despite 20‐fold variation in the frequency of encounters between wolves and individual elk, the risk of predation was not associated with elk body fat or pregnancy. Our findings suggest that the ecological consequences of actively hunting large carnivores, such as the wolf, are more likely transmitted by consumptive effects on prey survival than NCEs on prey behaviour.