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Fragmentation of the boreal forest by linear features, including seismic lines, has destabilized predator-prey dynamics, resulting in the decline of woodland caribou (Rangifer tarandus caribou) populations. Restoration of human-altered habitat has therefore been identified as a critical management tool for achieving self-sustaining woodland caribou populations. However, only recently has testing of the response of caribou and other wildlife to restoration activities been conducted. Early work has centered around assessing changes in wildlife use of restored seismic lines. We evaluated whether restoration reduces the movement rates of predators and their associated prey, which is expected to decrease predator hunting efficiency and ultimately reduce caribou mortality. We developed a new method for using cameras to measure fine-scale movement by measuring speed as animals traveled between cameras in an array. We used our method to quantify speed of caribou, moose (Alces alces), bears (Ursus americanus), and wolves (Canis lupus) on treated (restored) and untreated seismic lines. Restoration treatments reduced travel speeds along seismic lines of wolves by 1.38 km/h, bears by 0.55 km/h, and caribou by 1.57 km/h, but did not reduce moose travel speeds. Reduced predator and caribou speeds on treated seismic lines are predicted to decrease encounter rates between predators and caribou and thus lower caribou kill rates. However, further work is needed to determine whether reduced movement rates result in reduced encounter rates with prey, and ultimately reduced caribou mortality., (© 2022 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)

Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others. Understanding the environmental context and species traits that give rise to these divergent outcomes is a major challenge to the generality of both theoretical and applied ecology. In aquatic systems, nutrient-mediated eutrophication has led to major declines in species diversity, motivating us to seek terrestrial analogues using a large-mammal system across 598 000 km 2 of the Canadian boreal forest. These forests are undergoing some of the most rapid rates of land-use change on Earth and are home to declining caribou ( Rangifer tarandus caribou ) populations. Using satellite-derived estimates of primary productivity, coupled with estimates of moose ( Alces alces ) and wolf ( Canis lupus ) abundance, we used path analyses to discriminate among hypotheses explaining how habitat alteration can affect caribou population growth. Hypotheses included food limitation, resource dominance by moose over caribou, and apparent competition with predators shared between moose and caribou. Results support apparent competition and yield estimates of wolf densities (1.8 individuals 1000 km -2 ) above which caribou populations decline. Our multi-trophic analysis provides insight into the cascading effects of habitat alteration from forest cutting that destabilize terrestrial predator-prey dynamics. Finally, the path analysis highlights why conservation actions directed at the proximate cause of caribou decline have been more successful in the near term than those directed further along the trophic chain.

Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others. Understanding the environmental context and species traits that give rise to these divergent outcomes is a major challenge to the generality of both theoretical and applied ecology. In aquatic systems, nutrient-mediated eutrophication has led to major declines in species diversity, motivating us to seek terrestrial analogues using a large-mammal system across 598 000 km2 of the Canadian boreal forest. These forests are undergoing some of the most rapid rates of land-use change on Earth and are home to declining caribou (Rangifer tarandus caribou) populations. Using satellite-derived estimates of primary productivity, coupled with estimates of moose (Alces alces) and wolf (Canis lupus) abundance, we used path analyses to discriminate among hypotheses explaining how habitat alteration can affect caribou population growth. Hypotheses included food limitation, resource dominance by moose over caribou, and apparent competition with predators shared between moose and caribou. Results support apparent competition and yield estimates of wolf densities (1.8 individuals 1000 km−2) above which caribou populations decline. Our multi-trophic analysis provides insight into the cascading effects of habitat alteration from forest cutting that destabilize terrestrial predator–prey dynamics. Finally, the path analysis highlights why conservation actions directed at the proximate cause of caribou decline have been more successful in the near term than those directed further along the trophic chain. [ABSTRACT FROM AUTHOR]

Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others. Understanding the environmental context and species traits that give rise to these divergent outcomes is a major challenge to the generality of both theoretical and applied ecology. In aquatic systems, nutrient-mediated eutrophication has led to major declines in species diversity, motivating us to seek terrestrial analogues using a large-mammal system across 598 000 km2 of the Canadian boreal forest. These forests are undergoing some of the most rapid rates of land-use change on Earth and are home to declining caribou (Rangifer tarandus caribou) populations. Using satellite-derived estimates of primary productivity, coupled with estimates of moose (Alces alces) and wolf (Canis lupus) abundance, we used path analyses to discriminate among hypotheses explaining how habitat alteration can affect caribou population growth. Hypotheses included food limitation, resource dominance by moose over caribou, and apparent competition with predators shared between moose and caribou. Results support apparent competition and yield estimates of wolf densities (1.8 individuals 1000 km−2) above which caribou populations decline. Our multi-trophic analysis provides insight into the cascading effects of habitat alteration from forest cutting that destabilize terrestrial predator–prey dynamics. Finally, the path analysis highlights why conservation actions directed at the proximate cause of caribou decline have been more successful in the near term than those directed further along the trophic chain. [ABSTRACT FROM AUTHOR]

One of the most challenging tasks in wildlife conservation and management is to clarify how spatial variation in land cover due to anthropogenic disturbance influences wildlife demography and long‐term viability. To evaluate this, we compared rates of survival and population growth by woodland caribou (Rangifer tarandus caribou) from 2 study sites in northern Ontario, Canada that differed in the degree of anthropogenic disturbance because of commercial logging and road development, resulting in differences in predation risk due to gray wolves (Canis lupus). We used an individual‐based model for population viability analysis (PVA) that incorporated adaptive patterns of caribou movement in relation to predation risk and food availability to predict stochastic variation in rates of caribou survival. Field estimates of annual survival rates for adult female caribou in the unlogged (x¯= 0.90) and logged (x¯= 0.76) study sites recorded during 2010–2014 did not differ significantly (P > 0.05) from values predicted by the individual‐based PVA model (unlogged: x¯ = 0.87; logged: x¯= 0.79). Outcomes from the individual‐based PVA model and a simpler stage‐structured matrix model suggest that substantial differences in adult survival largely due to wolf predation are likely to lead to long‐term decline of woodland caribou in the commercially logged landscape, whereas the unlogged landscape should be considerably more capable of sustaining caribou. Estimates of population growth rates (λ) for the 2010–2014 period differed little between the matrix model and the individual‐based PVA model for the unlogged (matrix model x¯ = 1.01; individual‐based model x¯ = 0.98) and logged landscape (matrix model x¯ = 0.88; individual‐based model x¯ = 0.89). We applied the spatially explicit PVA model to assess the viability of woodland caribou across 14 woodland caribou ranges in Ontario. Outcomes of these simulations suggest that woodland caribou ranges that have experienced significant levels of commercial forestry activities in the past had annual growth rates <0.89, whereas caribou ranges that had not experienced commercial forestry operations had population growth rates >0.96. These differences were strongly related to regional variation in wolf densities. Our results suggest that increased wolf predation risk due to anthropogenic disturbance is of sufficient magnitude to cause appreciable risk of population decline in woodland caribou in Ontario. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society. We used matrix and individual‐based population viability assessment models to compare the demography of woodland caribou populations in Ontario in unlogged landscapes with those in logged landscapes. Our results suggest that increased wolf predation risk due to anthropogenic disturbance is of sufficient magnitude to cause appreciable risk of population decline in woodland caribou in Ontario. [ABSTRACT FROM AUTHOR]

Understanding how organisms distribute themselves in response to interacting species, ecosystems, climate, human development and time is fundamental to ecological study and practice. A measure to quantify the relationship among organisms and their environments is intensity of use: the rate of use of a specific resource in a defined unit of time. Estimating the intensity of use differs from estimating probabilities of occupancy or selection, which can remain constant even when the intensity of use varies. We describe a method to evaluate the intensity of use across conditions that vary in both space and time. We demonstrate its application on a large mammal community where linear developments and human activity are conjectured to influence the interactions between white‐tailed deer (Odocoileus virginianus) and wolves (Canis lupus) with possible consequences on threatened woodland caribou (Rangifer tarandus caribou).We collect and quantify intensity of use data for multiple, interacting species with the goal of assessing management efficacy, including a habitat restoration strategy for linear developments. We test whether blocking linear developments by spreading logs across a 200‐m interval can be applied as an immediate mitigation to reduce the intensities of use by humans, predator and prey species in a boreal caribou range.We deployed camera traps on linear developments with and without restoration treatments in a landscape exposed to both timber and oil development. We collected a three‐year dataset and employed spatial recurrent event models to analyse intensity of use by an interacting human and large mammal community across a range of environmental and climatic conditions.Spatial recurrent event models revealed that intensity of use by humans influenced the intensity of use by all five large mammal species evaluated, and the intensities of use by wolves and deer were inextricably linked in space and time. Conditions that resist travel on linear developments had a strong negative effect on the intensity of human and large mammal use.Mitigation strategies that resist, or redirect, animal travel on linear developments can reduce the effects of resource development on interacting human and predator–prey interactions. Our approach is easily applied to other continuous time point‐based survey methodologies and shows that measuring the intensity of use within animal communities can help scientists monitor, mitigate and understand ecological states and processes. [ABSTRACT FROM AUTHOR]

Abstract Management of wildlife often relies upon understanding mechanisms linking anthropogenic disturbance to population declines. The most-cited mechanism by which disturbance threatens boreal caribou (Rangifer tarandus caribou) is the exacerbation of apparent competition via increases in early successional forage, and subsequent changes in the densities and distributions of other prey species and gray wolves (Canis lupus). An alternative mechanism is the direct alteration of wolf distribution via positive responses by wolves to anthropogenic features. We conducted a mechanistic evaluation of hypotheses explaining human-mediated increases in boreal caribou mortality across northeast British Columbia. We evaluated support for (i) numeric apparent competition (increased prey densities) by evaluating relationships between disturbances, moose (Alces alces) density, and caribou survival. To evaluate (ii) spatial apparent competition (altered prey distribution) and (iii) wolf spatial responses (altered wolf distribution independent of prey), we modeled the relationships between disturbances and indices of caribou-moose and caribou-wolf co-occurrence and then examined predation risk for caribou as a function of co-occurrence. We did not detect any relationships between anthropogenic disturbances, moose density, and caribou survival. Although caribou-moose co-occurrence increased predation risk, we observed both positive and negative relationships between disturbances and caribou-moose co-occurrence. In contrast, caribou-wolf co-occurrence increased predation risk and was positively correlated with anthropogenic linear features. Contrary to other boreal caribou populations, our analyses demonstrate stronger support for the direct effects of anthropogenic linear features on caribou-wolf spatial overlap, leading to greater risk for caribou. Our research highlights the need for region-specific management actions to conserve and recover widely distributed species. Highlights • Boreal caribou are federally listed as threatened across their range as a result of resource extraction • Human-mediated apparent competition with other prey species is theorized as the primary mechanism of decline • In northeast British Columbia, the effect of anthropogenic linear features on caribou-wolf encounters is better supported • Limiting future and restoring existing linear features is recommended for caribou recovery in northeast British Columbia • Regional management actions are often necessary for the conservation of widely distributed species [ABSTRACT FROM AUTHOR]

Woodland caribou (Rangifer tarandus caribou) in Ontario are a threatened species that have experienced a substantial retraction of their historic range. Part of their decline has been attributed to increasing densities of anthropogenic linear features such as trails, roads, railways, and hydro lines. These features have been shown to increase the search efficiency and kill rate of wolves. However, it is unclear whether selection for anthropogenic linear features is additive or compensatory to selection for natural (water) linear features which may also be used for travel. We studied the selection of water and anthropogenic linear features by 52 resident wolves (Canis lupus x lycaon) over four years across three study areas in northern Ontario that varied in degrees of forestry activity and human disturbance. We used Euclidean distance-based resource selection functions (mixed-effects logistic regression) at the seasonal range scale with random coefficients for distance to water linear features, primary/secondary roads/railways, and hydro lines, and tertiary roads to estimate the strength of selection for each linear feature and for several habitat types, while accounting for availability of each feature. Next, we investigated the trade-off between selection for anthropogenic and water linear features. Wolves selected both anthropogenic and water linear features; selection for anthropogenic features was stronger than for water during the rendezvous season. Selection for anthropogenic linear features increased with increasing density of these features on the landscape, while selection for natural linear features declined, indicating compensatory selection of anthropogenic linear features. These results have implications for woodland caribou conservation. Prey encounter rates between wolves and caribou seem to be strongly influenced by increasing linear feature densities. This behavioral mechanism–a compensatory functional response to anthropogenic linear feature density resulting in decreased use of natural travel corridors–has negative consequences for the viability of woodland caribou. [ABSTRACT FROM AUTHOR]

Grey Wolves (Canis lupus) are a leading proximate cause of declining populations of Woodland Caribou (Rangifer tarandus), a threatened species. Although predation on adult caribou has been well documented, less is known about predation on neonatal calves. We used scat analysis to examine the diet of wolves in an area of Ontario overlapping the receding southern limit of caribou occurrence. Wolves consumed mostly Moose (Alces americanus; 82.7%), followed by American Beaver (Castor canadensis; 10.9%), caribou (3.1 %), and Snowshoe Hare (Lepus americanus', 1.5%). This low use of caribou is consistent with other evidence suggesting that caribou are a minor dietary component of wolves in this system; however, because most caribou consumption consists of calves, the impact on this slowly reproducing species may still be significant. [ABSTRACT FROM AUTHOR]

Ecological theory predicts that the intensity of antipredator responses is dependent upon the spatiotemporal context of predation risk (the risk allocation hypothesis). However, most studies to date have been conducted over small spatial extents, and did not fully take into account gradual responses to predator proximity. We simultaneously collected spatially explicit data on predator and prey to investigate acute responses of a threatened forest ungulate, the boreal caribou (Rangifer tarandus), to the spatiotemporal dynamics of wolf (Canis lupus) distribution during spring. Movement analysis of GPS-collared individuals from both species revealed high plasticity in habitat-selection decisions of caribou. Female caribou avoided open areas and deciduous forests and moved relatively fast and toward foraging areas when wolves were closer than 2.5 km. Caribou also avoided food-rich areas only when wolves were within 1 km. Our results bridge the gap between long-term perceived risk and immediate flight responses by revealing dynamic antipredator tactics in response to predator proximity. [ABSTRACT FROM AUTHOR]

Across Canada, woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)) populations are declining because of human-induced changes to food webs that are resulting in apparent competition-induced increases in predator-caused caribou mortality. We tested the hypothesis that wolf ( Canis lupus L., 1758) population reduction could reverse declines in a woodland caribou population following a BACI (before-after-control-impact) design conducted over a 12-year period in west-central Alberta, Canada. We monitored annual survival for 172 adult female caribou and calf recruitment from 2000 through 2012 and conducted a provincial government delivered wolf population reduction program annually during the winters of 2005-2006 to 2012 (inclusive) in an area centered on the Little Smoky range. Wolf removal translated to a 4.6% increase in mean population growth rate of the Little Smoky population mostly through improvements in calf recruitment. In contrast, the Red Rock Prairie Creek control population exhibited a 4.7% decline. Although the wolf population reduction program appeared to stabilize the Little Smoky population, it did not lead to population increase, however, with λ remaining approximately equal to 1. Therefore, we recommend, if required, predation management be combined with effective habitat conservation and long-term planning to effect the recovery of species, such as woodland caribou, which are declining as a result of habitat-mediated apparent competition. [ABSTRACT FROM AUTHOR]

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A central assumption underlying the study of habitat selection is that selected habitats confer enhanced fitness. Unfortunately, this assumption is rarely tested, and in some systems, gradients of predation risk may more accurately characterize spatial variation in vital rates than gradients described by habitat selection studies., Here, we separately measured spatial patterns of both resource selection and predation risk and tested their relationships with a key demographic trait, adult female survival, for a threatened ungulate, woodland caribou ( Rangifer tarandus caribou Gmelin). We also evaluated whether exposure to gradients in both predation risk and resource selection value was manifested temporally through instantaneous or seasonal effects on survival outcomes., We used Cox proportional hazards spatial survival modelling to assess the relative support for 5 selection- and risk-based definitions of habitat quality, as quantified by woodland caribou adult female survival. These hypotheses included scenarios in which selection ideally mirrored survival, risk entirely drove survival, non-ideal selection correlated with survival but with additive risk effects, an ecological trap with maladaptive selection and a non-spatial effect of annual variation in weather., Indeed, we found positive relationships between the predicted values of a resource selection function ( RSF) and survival, yet subsequently incorporating an additional negative effect of predation risk greatly improved models further. This revealed a positive, but non-ideal relationship between selection and survival. Gradients in these covariates were also shown to affect individual survival probability at multiple temporal scales. Exposure to increased predation risk had a relatively instantaneous effect on survival outcomes, whereas variation in habitat suitability predicted by an RSF had both instantaneous and longer-term seasonal effects on survival., Predation risk was an additive source of hazard beyond that detected through selection alone, and woodland caribou selection thus was shown to be non-ideal. Furthermore, by combining spatial adult female survival models with herd-specific estimates of recruitment in matrix population models, we estimated a spatially explicit landscape of population growth predictions for this endangered species. [ABSTRACT FROM AUTHOR]

Woodland caribou ( Rangifer tarandus caribou) are a species of increasing conservation concern across North America. Throughout much of boreal Canada, human developments, including forestry and energy development, are now accepted causes of the decline in the number and distribution of caribou. One of the hypothesised mechanisms for the decline is altered predator-prey dynamics. We quantified the impacts of a variety of industrial activities on gray wolf ( Canis lupus) and caribou interactions at a regional scale. We used animal locations collected with global positioning system collars and field data to examine how a range of industrial developments influenced the movements of wolves. We quantified the speed of wolf movements and the tortuosity of movement paths at two spatiotemporal scales across forested boreal and mountainous environments occupied by woodland caribou. Habitat and disturbance features better explained wolf movements during the weekly scale. In general, linear movements increased during winter, which paralleled past studies that suggested linear travel by wolves was associated with deep snow and the increased maintenance and patrol of territories. Wolves decreased movement rates but not sinuosity within close proximity to disturbance features, thus implying behaviours near such features were more closely associated with prey searching and hunting. Alternatively, wolves increased movement rates and linear travel through areas with high densities of linear and non-linear industrial features; this response suggested that wolves avoided spending time in high-risk areas associated with human activities. Results of this study further our understanding of wolf distribution and behaviour in habitats supporting populations of caribou within a matrix of industrial developments. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Woodland caribou in the southern portion of Jasper National Park have declined from an estimated 435 in the mid 1970s to a population estimate of 87 in the fall of 2009. We examined the available historical information to determine why caribou have declined. We compared three main hypotheses for caribou decline in JNP: human disturbance, climate change, and wildlife management. We used historical human use statistics, climate data, and animal abundance information to weigh the evidence for these competing hypotheses over two time scales. Caribou decline could not be attributed to changes in climate over the long-term, or an increase in human use (our proxy for disturbance). Caribou decline was attributed to a combination of climate and wildlife management. Recovery of caribou in Jasper National Park will likely be contingent on managing the interaction between the predator/prey dynamic and climate change.

Predation risk is an important driver of ecosystems, and local spatial variation in risk can have population-level consequences by affecting multiple components of the predation process. I use resource selection and proportional hazard time-to-event modelling to assess the spatial drivers of two key components of risk -- the search rate (i.e. aggregative response) and predation efficiency rate (i.e. functional response) -- imposed by wolves (Canis lupus) in a multi-prey system. In my study area, both components of risk increased according to topographic variation, but anthropogenic features affected only the search rate. Predicted models of the cumulative hazard, or risk of a kill, underlying wolf search paths validated well with broad-scale variation in kill rates, suggesting that spatial hazard models provide a means of scaling up from local heterogeneity in predation risk to population-level dynamics in predator-prey systems. Additionally, I estimated an integrated model of relative spatial predation risk as the product of the search and efficiency rates, combining the distinct contributions of spatial heterogeneity to each component of risk. [ABSTRACT FROM AUTHOR]

The article discusses research by biologists John Fryxell, Jim Baker, and team into the decline of woodland caribou (Rangifer tarandus caribou) in Ontario, Canada using population viability analysis (PVA) to identify potential causes and conservation remedies. Two ecotypes of Ontario caribou are described, one that migrates between tundra and boreal forest and one which remains in the boreal forest in every season. The caribou habitat has been altered by deforestation from logging and mining, as well as changes in forest composition caused by global warming. The PVA looked at factors such as increased competition between caribou and moose and predation by wolves as the species are driven into new habitats, parasitism by black flies, and caribou feeding on mosses and lichens.

Morphological analysis of wolves associated with woodland caribou in late succession boreal coniferous forests north of the commercial cut line and those associated with moose in early succession boreal deciduous forests south of the commercial cut line were studied in Ontario. So-called "moose-wolves" could readily be distinguished from "caribouwolves" in both genders using a few morphological measurements. Wolves associated with woodland caribou were significantly smaller in most measurements, and increased in size within seven years post-harvest as moose totally replaced caribou in the ecosystem. Whether this change in wolf morphology is related to micro-evolutionary change, the migration of larger "moose-wolves" into the area, or both, remains unclear. [ABSTRACT FROM AUTHOR]

Fire management is an important conservation tool in Canada's national parks. Fires can benefit some species, while others may be negatively impacted. We used GPS and VHF collar data for 47 wolves from 12 separate packs and 153 caribou from 5 separate herds, and resource selection analysis to model the effects of fire on these species' habitat and potential interactions. Resource selection modeling showed that wolves select for burned areas and areas close to burns, presumably due to the presence of primary prey (i.e., elk and moose), while caribou avoid burns. Fire reduced the amount of high quality caribou habitat (a direct effect), but also increased the probability of wolf-caribou overlap (an indirect effect). We delineated a spatial index of caribou "safe zones" (areas of low overlap with wolves), and found a positive relationship between the proportion of a herd's home range represented by "safe zone" in winter and population size (P = 0.10, n=4). While currently-planned prescribed fires in Banff and Jasper reduced the amount of quality caribou habitat by up to 4%, they reduced the area of "safe zones" by up to 7%, varying by herd, location, and season. We suggest that conservation managers should account for the indirect, predator-mediated impacts of fire on caribou in addition to direct effects of habitat loss. [ABSTRACT FROM AUTHOR]

Woodland caribou in the southern portion of Jasper National Park have declined from an estimated 435 in the mid 1970s to a population estimate of 87 in the fall of 2009. We examined the available historical information to determine why caribou have declined. We compared three main hypotheses for caribou decline in JNP: human disturbance, climate change, and wildlife management. We used historical human use statistics, climate data, and animal abundance information to weigh the evidence for these competing hypotheses over two time scales. Caribou decline could not be attributed to changes in climate over the long-term, or an increase in human use (our proxy for disturbance). Caribou decline was attributed to a combination of climate and wildlife management. Recovery of caribou in Jasper National Park will likely be contingent on managing the interaction between the predator/prey dynamic and climate change. [ABSTRACT FROM AUTHOR]

Human-caused habitat change has been implicated in current woodland caribou (Rangifer tarandus caribou) population declines across North America. Increased early seral habitat associated with industrial footprint can result in an increase in ungulate densities and subsequently those of their predator, wolves (Canis lupus). Higher wolf densities can result in increased encounters between wolves and caribou and consequently higher caribou mortality. We contrasted changes in moose (Alces alces) and deer (Odocoileus spp.) densities and assessed their effects on wolf-caribou dynamics in northeastern Alberta, Canada, pre (1994-1997) versus post (2005-2009) major industrial expansion in the region. Observable white-tailed deer (O. virginianus) increased 17.5-fold but moose remained unchanged. Wolf numbers also increased from approximately 6-11.5/1,000 km2. Coincident with these changes, spatial overlap between wolf pack territories and caribou range was high relative to the mid-1990s. The high number of wolf locations in caribou range suggests that forays were not merely exploratory, but rather represented hunting forays and denning locations. Scat analysis indicated that wolf consumption of moose declined substantively during this time period, whereas use of deer increased markedly and deer replaced moose as the primary prey of wolves. Caribou increased 10-fold in the diet of wolves and caribou population trends in the region changed from stable to declining. Wolf use of beaver (Castor canadensis) increased since the mid-1990s. We suggest that recent declines in woodland caribou populations in the southerly extent of their range have occurred because high deer densities resulted in a numeric response by wolves and consequently higher incidental predation on caribou. Our results indicate that management actions to conserve caribou must now include deer in primary prey and wolf reduction programs. [ABSTRACT FROM AUTHOR]

Various management plans have been developed to mitigate the effects of human activities on threatened woodland caribou (Rangifer tarandus caribou) populations. Most plans do not account for the behavior of wolves (Canis lupus), their main predator. The success of caribou recovery plans may nonetheless depend on how landscape management shapes wolf-caribou interactions. We evaluated the species-specific responses of caribou and wolves to a management plan in Québec, and assessed its impact on the probability of wolf-caribou co-occurrence. Landscape management consisted of the protection of large forest blocks, and the spatial aggregation of cutblocks. Based on telemetry data, we modeled animal-habitat spatial relationships with resource selection functions, and then estimate the relative probability of wolf-caribou co-occurrence. We found that caribou selected mature conifer forests with lichen. Wolves selected mixed and deciduous stands. Caribou avoided roads and cutblocks, while wolves selected them, which resulted in a relatively low probability of co-occurrence in harvested areas. Concurrent habitat selection by the two species was such that the highest probability of wolf-caribou cooccurrence took place in protected forest blocks (PB) from December to May. For efficient mitigation measures, the location of PBs should be selected while accounting for differences in habitat selection between wolf and caribou. The blocks should include mature conifer forests with lichen, minimize the abundance of mixed and deciduous stands, and be far from roads and cutblocks. Consideration of predator behavior can improve suitability of landscape management plans for the long-term persistence of threatened prey populations under top-down control. [ABSTRACT FROM AUTHOR]

Mountain caribou (Rangifer tarandus caribou) populations in south-eastern British Columbia are declining over most of their range and are listed as Threatened. Predation has been documented as the major cause of declining caribou numbers. Excessive predation by wolves (Canis lupus) has been related to increased moose (Alces alces) numbers. The increase in moose appears to be the result of a natural colonization process that has been enhanced by human-caused habitat change. Options to reduce the rate of predation include reducing wolves, reducing moose, and reducing the amount of early seral habitat that supports moose. Current management includes population control of moose and wolves. Monitoring and assessment of these approaches will guide the future management strategy used to maintain mountain caribou in south-eastern British Columbia. [ABSTRACT FROM AUTHOR]

A search was carried Out for historical records, both published and unpublished, that make reference to the native mammalian fauna of Prince Edward Island. Based on documents dating from 1721 to 1890, a comprehensive list of the records for the native mammals of the island has been compiled. Among the new information found is evidence for the presence of the Grey Wolf (as well as the Woodland Caribou) at the time of the first French settlement in 1720, and for the absence of the Beaver and Moose. Historical information has been assembled on the abundance and food-chain relationships of each of the mammalian species, as well as on their interactions with the European population, including the attitudes of the new settlers towards each species. The records indicate that seven of the mammals were extirpated: the Grey Wolf, American Black Bear, American Marten, River Otter, Canada Lynx, Atlantic Walrus and Woodland Caribou. All of these extirpations were due to the activities of the European population, with the attitudes of the settlers contributing to four of them: an indifference to the survival of the otter and Marten, and a direct hostility to the bear and lynx (due to their predation on livestock), leading to the payment of bounties. [ABSTRACT FROM AUTHOR]

Limiting factors of caribou (Rangifer tarandus) populations vary regionally. In tundra environments, this species appears to be regulated by food, either because wolves (Canis lupus) are absent or because migration of caribou allows escape from predation during part of the year. In the boreal forest, the main limiting factors are hunting and predation but because of low caribou densities, no regulation mechanism seems to exist between caribou and wolves. Moose (AIces alces) is the primary prey species of wolves and consequently, if moose abundance increases, wolves should also increase, independently of the caribou population. Thus, caribou could experience high predation rates and be eliminated in high wolf densities. Here we attempted to identify the necessary conditions to maintain caribou numbers in the presence of moose. To do so, we built a deterministic model that simulated the relationship between a caribou population regulated by food competition and limited by predation, a moose population regulated by predation, and a wolf population, the abundance of which is determined by moose abundance. At current hunting rates for caribou and moose in the boreal forest, and in the absence of wolf trapping, the model predicted that the caribou population would be extirpated in approximately 100 years. Wolf trapping was not adequate to conserve the caribou population unless very intensive control was undertaken. In the absence of trapping, cessation of caribou hunting allowed a 3-fold increase in caribou numbers over the long term, if the moose population remained low. According to our model, the best management measure for caribou consisted of maintaining a low moose density through appropriate population and habitat management strategies, which prevented expansion of the wolf population and limited predation on caribou. [ABSTRACT FROM AUTHOR]

We studied pack size of Wolves (Can& lupus) on Woodland Caribou (Rangifer tarandus caribou) winter ranges in westcentral Alberta. These Caribou winter ranges are experiencing increasing pressure from resource extraction industries (forestry, energy sector) and concerns have been raised regarding increased Wolf predation pressure on Caribou in conjunction with landscape change. Thirty-one Wolves, from eight Wolf packs, were fitted with radiocollars on two Caribou winter ranges in the Rocky Mountain foothills, near Grande Cache, Alberta (2000-2001). There was a mean of 8.2 Wolves/pack and between 30 and 39 Wolves on each of the RedRock/Prairie Creek and Little Smoky Caribou ranges. The average pack size of Wolves in this region does not appear to have increased over that recorded historically, but the range (5-18) in the number of Wolves per pack varied considerably over our study area. Wolves preyed predominately on Moose (Alces alces), averaging one Moose kill every three to five days. There was some indication that pack size was related to prey size, with the smallest pack preying on Deer (Odocoileus spp.). It was clear that Caribou could not be the primary prey for Wolves, due to their low numbers, and relative to the pack size and Wolf kills we observed. [ABSTRACT FROM AUTHOR]

Recent advancements in Global Positioning Systems (GPS) radiocollar technology permit analysis of fine-scale animal movements. We used concurrent aerial and GPS monitoring to determine winter travel rates of Wolves (Canis lupus) in relation to ungulate kill sites in managed forest landscapes in westcentral Alberta. Wolves preyed predominately on Moose (AIces alces) and travelled 4.2 times less when near ungulate kill sites than when away from them. As Wolves are thought to be an important factor in Woodland Caribou (Rangifer tarandus caribou) declines, information is needed to assess predation risk to Caribou from Wolves under a variety of landscape conditions. If Wolves have restricted movements near Moose kill sites, this may lead to decreased encounter rates with Caribou in systems where Moose are abundant. Deer (Odocoileus spp.) are probably an important component of this Wolf-prey system but little is currently known about this relationship. Projecting long-term implications of ongoing development activities requires a more detailed understanding of the responses of all species to landscape change. [ABSTRACT FROM AUTHOR]

In northeastern Alberta, Canada, continued expansion of the oil and gas industry along with timber harvesting has raised concerns that the resulting environmental changes may negatively affect the woodland caribou (Rangifer tarandus caribou) population in this region. Caribou are a threatened species in Alberta, and populations in northeastern Alberta appear to be stable or slightly decreasing. The spatial distribution of caribou in relation to alternative prey (commonly moose [Alces alces]) has been hypothesized to affect the level of wolf (Canis lupus) predation on caribou populations. We monitored radiomarked caribou, moose, and wolves between 1993 and 1997, and we found that selection of fen/bog complexes by caribou and selection of well-drained habitats by moose and wolves resulted in spatial separation. This spatial separation in turn reduced wolf predation pressure on caribou but did not provide a total refuge from wolves. Any management activities that increase the density of moose and wolves or increase access of wolves into fen/bog complexes will likely reduce the refuge effect provided by large fen/bog complexes. [ABSTRACT FROM AUTHOR]

It is generally accepted that predation by wolves Canis lupus is one of the major factors limiting densities of woodland caribou Rangifer tarandus caribou in North America. Conversely, little is known about the role of European wild forest reindeer R. t. fennicus as wolf prey, or about the influence of wolf predation on populations of this rare subspecies. This relationship was examined in east-central Finland, where wild forest reindeer coexist with moose Alces alces at a numerical ratio of c. 1 reindeer to 1.5 moose. During the study, moose were clearly the primary prey of wolves. Reindeer were, however, an important part of wolf diet in summer, autumn and early winter, when their remains comprised roughly 20–50% of all food items identified in wolf scats. Wolves exhibited a slight preference for reindeer over moose as prey during early winter (November–December) when the reindeer were moving towards their wintering ranges. Virtually no reindeer were killed by wolves during midwinter (January–March). This held also for a pack whose territory was located in the middle of the wintering range of reindeer, where reindeer outnumbered moose during the winter months. After the approximate ratio of wolves to reindeer increased from 0.004 (1998) to 0.02 (2000), wolf predation became the most common source of mortality (50%) for reindeer. The annual net increase in the reindeer population decreased from 13% to 7% because of increased wolf predation. The results indicate that wolf predation was an important factor limiting reindeer population growth. Wolves were, however, unable to prevent entirely the number of reindeer from increasing, partly owing to behavioural traits used by reindeer during winter and calving times. [ABSTRACT FROM AUTHOR]

Managing predators to restore threatened or endangered species is often controversial. Hervieux et al. (2014; Can. J. Zool. 92(12): 1029-1037) report on the efficacy of wolf ( Canis lupus L., 1758) reduction as a recovery strategy in the Little Smoky population of boreal woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)) range in Alberta, which generated a lot of media attention. As such, the authors were invited by the journal editor who handled the original paper to write this addendum to provide clarification regarding the methodology used in the original paper. Wolf reduction was conducted by Government personnel in accordance with appropriate policy and laws (i.e., federal and provincial Species at Risk Acts; Alberta Wildlife Act; Alberta Woodland Caribou Policy). University-based researchers were involved only in data analysis and writing, and thus did not require approval by a university-based animal welfare board. Collaboration between independent university-based scientists and government biologists is essential to effective assessment of such controversial management practices. Hervieux et al. (2014; Can. J. Zool. 92(12): 1029-1037) in fact concluded that such wolf reductions, by themselves, would only 'buy time' and would not restore woodland caribou alone without effective habitat protection. [ABSTRACT FROM AUTHOR]

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How to mitigate the impacts of anthropogenic habitat alteration and restore ecological processes has become an imperative question facing applied ecology. One high-profile example in Canada is boreal woodland caribou, which are declining across North America largely due to anthropogenic habitat alteration and associated changes to predator-prey dynamics. Habitat restoration is increasingly being implemented to recover habitat, as is mandated by federal law. But given the extent of the disturbance and the cost to conduct restoration, evaluating the effectiveness of restoration treatments is needed for effective recovery of caribou populations. We evaluated the effectiveness of silvicultural treatments to reduce predator (wolf and bear) and prey (moose and caribou) use of linear features using a multiple lines of evidence approach. All four species were less likely to be present at treated sites than untreated sites, and daily photo capture rates of moose and wolves when present at treated sites also declined; though effect sizes were typically small. Complimenting the camera-based results, individual moose, bears, and wolves monitored with GPS collars also showed a decline in the use of treated linear features, particularly those with higher intensity treatments, though the response was non-significant. The reduction in the use of treated lines did not scale-up into a significant decline in overall line-use within the treatment area. While we found more evidence than not supporting that animals reduced use of the restoration sites, our study highlights the complexity of monitoring and evaluating the success of habitat restoration. Understanding long-term responses is imperative to ensure habitat restoration is effective. [ABSTRACT FROM AUTHOR]

Hypothesizes about the causes of decline of woodland caribou in Red Wine Mountains in central Labrador, Newfoundland particularly the effect of gray wolf predation to the population. Changes in mean age, sex ratio, and rates of recruitment, mortality and emigration of caribou; Implications of higher densities of moose and migratory caribou.