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American black bears (Ursus americanus Pallas, 1780) are opportunistic foragers, and across most of their range in North America, their diet is predominantly vegetation with limited consumption of vertebrates and invertebrates. However, they are also predators of ungulates, especially neonates, with regional variation in the amount of predation pressure they exert. We used scat analysis to examine the diet of black bears during the calving season in a moose (Alces alces (Linnaeus, 1758)) – woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) system in the Boreal forest of northern Ontario, Canada. Bears consumed herbaceous plants (46.5%), fruits and (or) seeds (20.0%), moose (3.3% adults; 4.3% calves), American beaver (Castor canadensis Kuhl, 1820; 8.5%), and insects (mostly ants; 4.2%). Bears had the highest consumption of moose and beaver in early spring, before switching to a more vegetation-dominated diet. We did not detect evidence of caribou consumption. Based on our results, black bear consumption of moose, particularly neonates, may warrant further investigation.

The interplay of predator encounters and antipredator responses is an integral part of understanding predator–prey interactions and spatial co-occurrence and avoidance can elucidate these interactions. We conducted hard-part dietary analysis of coyotes (Canis latrans Say, 1823) and space use of coyotes and woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) to test two competing hypotheses about coyote and caribou predator–prey spatial dynamics using resource selection functions. The high encounter hypothesis predicts that coyotes would maximize encounters with caribou via high spatial co-occurrence, whereas the predator stealth hypothesis predicts that through low spatial co-occurrence with caribou, coyotes act as stealth predators by avoiding habitats that caribou typically select. Our dietary analysis revealed that ∼46% of sampled coyote diet is composed of caribou. We found that coyote share space with caribou in lichen-barren habitat in both summer and winter and that coyotes co-occur with caribou in forested habitat during summer, but not during winter. Our findings support predictions associated with the high encounter predator hypothesis whereby coyotes and caribou have high spatial co-occurrence promoting caribou in coyote diet.

In social species, reproductive success and rates of dispersal vary among individuals resulting in spatially structured populations. Network analyses of familial relationships may provide insights on how these parameters influence population‐level demographic patterns. These methods, however, have rarely been applied to genetically derived pedigree data from wild populations.Here, we use parent–offspring relationships to construct familial networks from polygamous boreal woodland caribou (Rangifer tarandus caribou) in Saskatchewan, Canada, to inform recovery efforts. We collected samples from 933 individuals at 15 variable microsatellite loci along with caribou‐specific primers for sex identification. Using network measures, we assess the contribution of individual caribou to the population with several centrality measures and then determine which measures are best suited to inform on the population demographic structure. We investigate the centrality of individuals from eighteen different local areas, along with the entire population.We found substantial differences in centrality of individuals in different local areas, that in turn contributed differently to the full network, highlighting the importance of analyzing networks at different scales. The full network revealed that boreal caribou in Saskatchewan form a complex, interconnected familial network, as the removal of edges with high betweenness did not result in distinct subgroups. Alpha, betweenness, and eccentricity centrality were the most informative measures to characterize the population demographic structure and for spatially identifying areas of highest fitness levels and family cohesion across the range. We found varied levels of dispersal, fitness, and cohesion in family groups. Synthesis and applications: Our results demonstrate the value of different network measures in assessing genetically derived familial networks. The spatial application of the familial networks identified individuals presenting different fitness levels, short‐ and long‐distance dispersing ability across the range in support of population monitoring and recovery efforts., Network analyses of familial relationships may provide insights on how fitness influences population‐level demographic patterns in socially structured populations. Here, we use networks to reconstruct parent‐offspring relationships and create a familial network from polygamous boreal woodland caribou (Rangifer tarandus caribou), assessing the contribution of individual caribou to the population with several centrality metrics and determine which metrics are best suited to inform on population demographic structure. The familial network revealed that boreal caribou in Saskatchewan form a complex, interconnected social network, and identified areas of higher fitness levels and social cohesion across the range in support of population monitoring and recovery efforts.

Landscape change is a key driver of biodiversity declines due to habitat loss and fragmentation, but spatially shifting resources can also facilitate range expansion and invasion. Invasive populations are reproductively successful, and landscape change may buoy this success.We show how modeling the spatial structure of reproductive success can elucidate the mechanisms of range shifts and sustained invasions for mammalian species with attendant young. We use an example of white‐tailed deer (deer; Odocoileus virginianus) expansion in the Nearctic boreal forest, a North American phenomenon implicated in severe declines of threatened woodland caribou (Rangifer tarandus).We hypothesized that deer reproductive success is linked to forage subsidies provided by extensive landscape change via resource extraction. We measured deer occurrence using data from 62 camera traps in northern Alberta, Canada, over three years. We weighed support for multiple competing hypotheses about deer reproductive success using multistate occupancy models and generalized linear models in an AIC‐based model selection framework.Spatial patterns of reproductive success were best explained by features associated with petroleum exploration and extraction, which offer early‐seral vegetation resource subsidies. Effect sizes of anthropogenic features eclipsed natural heterogeneity by two orders of magnitude. We conclude that anthropogenic early‐seral forage subsidies support high springtime reproductive success, mitigating or exceeding winter losses, maintaining populations. Synthesis and Applications. Modeling spatial structuring in reproductive success can become a key goal of remote camera‐based global networks, yielding ecological insights into mechanisms of invasion and range shifts to inform effective decision‐making for global biodiversity conservation., White‐tailed deer are expanding into the boreal with detrimental effects on the mammal community. Landscape change via resource extraction best explains successful deer reproduction in this boreal landscape.

By regulating successional dynamics in Canada’s boreal forest, fires can affect the distribution of the Threatened woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). Caribou tend to avoid areas burned within the last 40 years; however, few studies have compared pre-fire and post-fire caribou observations. In this study, we used caribou GPS locations from the Boreal Shield of Saskatchewan, Canada, to assess the short-term response of caribou to areas that burned while they were collared (hereafter recent burns). We used a “before–after, control–impact” design to compare the overlap of pre-fire and post-fire seasonal home ranges to the overlap of year-to-year seasonal home ranges. Caribou rarely encountered recent burns and when they did, they adjusted their space use in variable and complex ways that were largely indistinguishable from regular, interannual variation. Caribou tended to reduce use of recent burns in summer–autumn and winter, but not during the calving season, in some cases shifting their home range to incorporate more burned habitat. We conclude that recently burned areas (

Cladonia subgenus Cladina (the reindeer lichens) can be a dominant part of terrestrial ecosystems worldwide. They are particularly abundant in arctic-alpine and boreal regions, where they are a primary food source for woodland caribou/reindeer in winter months. Determining the growth rates of reindeer lichen is important for understanding and managing lichen regeneration following disturbances such as timber harvesting, mining, grazing, and wildfire. Regeneration and rehabilitation rates can be calculated with greater accuracy when growth rates are well understood. We provide a summary of 17 studies from 6 countries that determined the linear growth rates of three reindeer lichen groups, Cladonia arbuscula/mitis (mean = 4.7 mm/yr.), C. rangiferina/ C. stygia (mean = 5.1 mm/yr.), and C. stellaris (mean = 4.8 mm/yr.). We use linear growth rates as a proxy for over-all growth and biomass. Variables found to influence lichen growth rates are also discussed, which include light, moisture, temperature, air pollution, acid rain, precipitation, snow accumulation, substrate, age of individuals, and type of disturbance. These results can assist land managers in developing more accurate strategies for restoring lichens in disturbed areas.

Mountain caribou, a behaviourally and genetically distinct set of ecotypes of the Woodland caribou (Rangifer tarandus caribou) restricted to the mountains of western Canada, have undergone severe population declines in recent decades. Although a broad consensus exists that the ultimate driver of these declines has been the reduction of habitat upon which mountain caribou depend, research and policy attention has increasingly focused on predation. Recently, Serrouya et al. (Proc Nat Acad Sci USA 116:6181–6186, 2019) analysed population dynamics data from 18 subpopulations in British Columbia and Alberta, Canada, subject to different treatments and ‘controls’, and concluded that lethal wolf control and maternal caribou penning provide the most effective ways to stabilize population declines. Here we show that this inference was based on an unbalanced analytical approach that omitted a null scenario, excluded potentially confounding variables and employed irreproducible habitat alteration metrics. Our reanalysis of available data shows that ecotype identity is a better predictor of population trends than any adaptive management treatments considered by Serrouya et al. Disparate behavioural characteristics and responses to industrial disturbance among ecotypes suggest it may be incorrect to assume that adaptive management strategies that might benefit one ecotype are transferable to another.

Population monitoring is a critical part of effective wildlife management, but methods are prone to biases that can hinder our ability to accurately track changes in populations through time. Calf survival plays an important role in ungulate population dynamics and can be monitored using telemetry and herd composition surveys. These methods, however, are susceptible to unrepresentative sampling and violations of the assumption of equal detectability, respectively. Here, we capitalized on 55 herd‐wide estimates of woodland caribou (Rangifer tarandus caribou) calf survival in Newfoundland, Canada, using telemetry (n = 1,175 calves) and 249 herd‐wide estimates of calf:cow ratios (C:C) using herd composition surveys to investigate these potential biases. These data included 17 herd‐wide estimates replicated from both methods concurrently (n = 448 calves and n = 17 surveys) which we used to understand which processes and sampling biases contributed to disagreement between estimates of herd‐wide calf survival. We used Cox proportional hazards models to determine whether estimates of calf mortality risk were biased by the date a calf was collared. We also used linear mixed‐effects models to determine whether estimates of C:C ratios were biased by survey date and herd size. We found that calves collared later in the calving season had a higher mortality risk and that C:C tended to be higher for surveys conducted later in the autumn. When we used these relationships to modify estimates of herd‐wide calf survival derived from telemetry and herd composition surveys concurrently, we found that formerly disparate estimates of woodland caribou calf survival now overlapped (within a 95% confidence interval) in a majority of cases. Our case study highlights the potential of under‐appreciated biases to impact our understanding of population dynamics and suggests ways that managers can limit the influence of these biases in the two widely applied methods for estimating herd‐wide survival., We investigated whether estimates of calf mortality risk and calf:cow ratios were biased by unrepresentative sampling and violations of equal detectability, respectively, using 35 years of caribou monitoring data. We found that caribou calves collared later in the calving season had a higher mortality risk and caribou calf:cow ratios were higher when surveys were conducted later in the autumn. If these biases go undetected, they could impact management.

Multi-scale selection patterns can be understood from two perspectives: coarse-scale patterns as the summation of fine-scale patterns (scaling-up), or as a hierarchy produced from multiple contributory factors with differential effects on organismal fitness (hierarchical). We examined woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) selection of foraging locations across two spatiotemporal scales to test whether selection patterns between them were consistent (scaling-up) or different (hierarchical) to determine which framework most accurately describes their foraging behaviour. Seven adult female woodland caribou were equipped with GPS telemetry radio collars outfitted with high-definition video cameras that recorded woodland caribou foraging choices throughout the summer. Fine-scale data from videos combined with direct measurements in the field along movement trajectories obtained from GPS fixes were used to estimate (i) feeding station selection and (ii) food patch selection. We estimated resource selection functions for each scale following a use–availability structure. Woodland caribou exhibited resource selection at both scales. Apart from selection for species of the lichen Cladina (Nyl.) Nyl. and patches associated with high abundance of Cladina, few patterns were consistent across both scales. Our study suggests that even at very fine scales, woodland caribou selection for foraging locations is hierarchical in nature.

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 ( x̄ = 0.90) and logged ( x̄ = 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: x̄ = 0.87; logged: x̄ = 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 x̄ = 1.01; individual‐based model x̄ = 0.98) and logged landscape (matrix model x̄ = 0.88; individual‐based model x̄ = 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 0.96. 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.

Space‐use behaviour reflects trade‐offs in meeting ecological needs and can have consequences for individual survival and population demographics. The mechanisms underlying space use can be understood by simultaneously evaluating habitat selection and movement patterns, and fine‐resolution locational data are increasing our ability to do so.We use high‐resolution location data and an integrated step‐selection analysis to evaluate caribou, moose, bear, and wolf habitat selection and movement behaviour in response to anthropogenic habitat modification, though caribou data were limited. Space‐use response to anthropogenic linear features (LFs) by predators and prey is hypothesized to increase predator hunting efficiency and is thus believed to be a leading factor in woodland caribou declines in western Canada.We found that all species moved faster while on LFs. Wolves and bears were also attracted towards LFs, whereas prey species avoided them. Predators and prey responded less strongly and consistently to natural features such as streams, rivers and lakeshores. These findings are consistent with the hypothesis that LFs facilitate predator movement and increase hunting efficiency, while prey perceive such features as risky.Understanding the behavioural mechanisms underlying space‐use patterns is important in understanding how future land‐use may impact predator–prey interactions. Explicitly linking behaviour to fitness and demography will be important to fully understand the implications of management strategies., The authors provide a framework to combine habitat selection and movement behaviour to understand the mechanisms behind space‐use patterns. They then apply this framework to a predator–prey system of high socio‐economic value in Canada, woodland caribou, to understand caribou, moose, bear and wolf space use in relation to human habitat alteration.

Protecting wildlife within areas of resource extraction often involves reducing habitat fragmentation. In Canada, protecting threatened woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) populations requires preserving large areas of intact forest habitat, with some restrictions on industrial forestry activities. We present a linear programming model that assesses the trade-off between achieving an objective of habitat protection for caribou populations while maintaining desired levels of harvest in forest landscapes. The habitat-protection objective maximizes the amount of connected habitat that is accessible by caribou, and the forestry objective maximizes net revenues from timber harvest subject to even harvest flow, a harvest target, and environmental sustainability constraints. We applied the model to explore the habitat protection and harvesting scenarios in the Cold Lake caribou range, a 6726 km2 area of prime caribou habitat in Alberta, Canada. We evaluated harvest scenarios ranging from 0.1 Mm3·year–1 to maximum sustainable harvest levels over 0.7 Mm3·year–1 and assessed the impact of habitat protection measures on timber supply costs. Protecting caribou habitat by deferring or reallocating harvest increases the timber unit cost by Can$1.1–2.0 m–3. However, this impact can be partially mediated by extending the harvest to areas of oil and gas extraction to offset forgone harvest in areas of prime caribou habitat.

Woodland caribou (Rangifer tarandus) are threatened in Alberta in part due to the development of oil and gas resources. To inform best management practices for caribou, we assessed how proximity to wellsites influenced caribou habitat selection, and whether habitat selection varied across wellsite activity phases (i.e., drilling, producing, and inactive). We used location data from 37 GPS-collared caribou monitored between 2007 and 2013 in west-central Alberta to model habitat selection. Our results suggest the influence of wellsites on caribou habitat selection are temporally dynamic. The largest impacts occur when human activity at wellsites is greatest, however wellsites continue to influence caribou habitat selection after human activity ceases. Caribou avoided wellsites, and avoidance increased relative to the degree of activity at the nearest wellsite. During early winter, caribou avoided wellsites in the drilling phase more than inactive and producing wellsites. During late winter, caribou avoided wellsites in producing phases more than inactive wellsites. Caribou may benefit from management practices that include i) seasonal timing restrictions on drilling, ii) reductions of human activity at wellsites, whether in duration or intensity, iii) land-use planning to coordinate the placement of wellsites to minimize impacts to caribou and their habitat, and iv) prompt and effective restoration of wellsites to match original habitat conditions once production has stopped.

The Interior Wetbelt (IWB) of British Columbia, which includes the globally rare Inland Temperate Rainforest (ITR), contains primary forests poorly attributed and neglected in conservation planning. We evaluated the IWB and ITR using four IUCN Red List of Ecosystems Criteria: geographic distribution, environmental degradation (abiotic and biotic factors), and likelihood of ecosystem collapse. Clearcut logging (3.2M ha) represented 57% of all anthropogenic disturbances, reducing potential primary forest by 2.7 million ha (28%) for the IWB and 524,003 ha (39%) for the ITR. Decadal logging rates nearly doubled from 5.3% to 10.2% from 1970s–2000s. Core areas (buffered by 100-m from roads and developments) declined by 70% to 95% for the IWB and ITR, respectively. Vulnerable was assigned to karst, the only abiotic factor assessed, because it was associated with rare plants. For biotic factors, Old-Growth Birds were Vulnerable, Southern Woodland Caribou (Rangifer tarandus caribou) habitat and Sensitive Fish were Endangered, and Old-Growth Lichens habitat was Critical. Overall, the IWB was ranked as Endangered and the ITR as Critical with core area collapse possible within 9 to 18 years for the ITR, considered one of the world’s most imperiled temperate rainforests.

Habitat loss is often the ultimate cause of species endangerment and is also a leading factor inhibiting species recovery. For this reason, species‐at‐risk legislation, policies and plans typically focus on habitat conservation and restoration as mechanisms for recovery. To assess the effectiveness of these instruments in decelerating habitat loss, we evaluated spatiotemporal habitat changes for an iconic endangered species, woodland caribou (Rangifer tarandus caribou). We quantified changes in forest cover, a key proxy of caribou habitat, for all caribou subpopulations in Alberta and British Columbia, Canada. Despite efforts under federal and provincial recovery plans, and requirements listed under Canada's Species at Risk Act, caribou subpopulations lost twice as much habitat as they gained during a 12‐year period (2000–2012). Drivers of habitat loss varied by ecotype, with Boreal and Northern Mountain caribou affected most by forest fire and Southern Mountain caribou affected more by forest harvest. Our case study emphasizes critical gaps between recovery planning and habitat management actions, which are a core expectation under most species‐at‐risk legislation. Loss of caribou habitat from 2000 to 2018 has accelerated. Linear features within caribou ranges have also increased over time, particularly seismic lines within Boreal caribou ranges, and we estimated that only 5% of seismic lines have functionally regenerated. Our findings support the idea that short‐term recovery actions such as predator reductions and translocations will likely just delay caribou extinction in the absence of well‐considered habitat management. Given the magnitude of ongoing habitat change, it is clear that unless the cumulative impacts of land‐uses are effectively addressed through planning and management actions that consider anthropogenic and natural disturbances, we will fail to achieve self‐sustaining woodland caribou populations across much of North America.

Anthropogenic linear features can have negative effects on wildlife by altering movements or increasing risk. Spatial responses to linear features vary depending on local conditions (functional responses), including linear feature availability. Several studies explored functional responses of wildlife to linear features, but few examined responses of multiple interacting species. We evaluated functional responses of Threatened boreal woodland caribou (Rangifer tarandus caribou), moose (Alces alces), and gray wolves (Canis lupus) to roads and seismic lines (linear features created during fossil fuel exploration) to assess the influence these responses might have on predator–prey interactions. We estimated median distance to and the density of roads and seismic lines around used and available locations by landcover (peatlands and non-peatlands) and season for each individual. To quantify functional responses, we regressed use in response to availability in peatlands and non-peatlands across seasons and selected the most parsimonious models for each species. Boreal caribou generally avoided higher road density. Wolves selected areas closer to roads in peatlands and demonstrated selection or indifference to higher road density as availability increased. Female moose generally avoided areas with higher road density, except in early winter. Female caribou and moose demonstrated weaker responses to seismic line density. During calving, late summer, and early winter, wolves often selected for seismic line density, particularly in peatlands, when availability was high. Our analyses suggest that boreal caribou, moose, and wolves respond to linear features in complex ways that alter individual space-use and likely influence predation risk.

Human-caused habitat disturbances and climate change are leading threats to biodiversity. Studying the impacts of human activities on wildlife from a behavioral perspective is a relevant starting point to understand the mechanisms underlying population and species resistance and resilience to disturbances. In this study, we assessed the effects of weather (temperature and precipitation), habitat disturbances (roads and clearcuts), and natural habitat types on the space use patterns of a threatened boreal population of woodland caribou (Rangifer tarandus caribou). An extensive data set of 288,665 relocations from 50 adult females outfitted with GPS collars over 7 years in the boreal forest of Québec, Canada was used to evaluate residency time in natural and disturbed habitats for five distinct biologically defined periods. The most parsimonious linear mixed-effects model for each period showed that individuals stayed longer in more natural habitat types. During calving and summer, residency time decreased with increasing road density, whereas residency time decreased with increasing temperature during winter and spring. We found no evidence of a synergistic effect between daily weather and human disturbances on movement behavior of caribou, but consider their respective influence as additive. We also showed large individual variation in residency time, except during the calving period. Lower individual variation in residency time during calving may be explained by strong evolutionary constraints on behavior faced by females to ensure protection and survival of their offspring. Based on our results, we suggest keeping large patches of suitable and roadless habitat for caribou to favor the spacing-out antipredator strategy exhibited by females during calving. By tracking individuals over several complete annual cycles, we showed variation in the effects of daily weather and human disturbances on residency time across biological periods. Our study highlights that the inclusion of daily weather variables helps better understand space-use patterns of a threatened species.

The conservation of species at-risk has involved a wide range of recovery methods including population augmentation. Yet, there has been little formal evaluation of the efficacy of this potentially high risk and expensive approach. In the late 1990s, 32 mountain caribou (Rangifer tarandus caribou) were translocated to the Telkwa caribou herd in an effort to recover this declining population. We used Andersen–Gill survival models to explore the influence of forestry, linear features, and recreation on the survival of translocated and native caribou in the Telkwa herd as well as two control herds that had relatively little habitat disturbance and no translocation. We used location data from radio/GPS collars to monitor the mortality of individual caribou from the three populations over a 21-year period (1991–2012). Results suggested that forest harvest more negatively affected the survival of Telkwa caribou when compared to neighbouring herds and that translocated caribou were not predisposed to higher mortality relative to native caribou. Although the translocation effort stabilised the decline of the Telkwa caribou for a 10-year period, this herd has now declined to 22 individuals. Our research suggests that well managed translocation programs can result in the short-term stabilization or increase of small and declining populations of species at-risk. To achieve long-term recovery objectives, however, conservation strategies must address the underlying causes of decline. For woodland caribou in the mountains of western Canada, this requires managing anthropogenic disturbance to minimize densities of primary prey and their predators that act in concert to decrease the survival of adult caribou.

Understanding how conservation of woodland caribou, an at-risk species for which large undisturbed areas are often proposed to maintain viable populations, can contribute to conservation of boreal biodiversity is an important consideration for an ecosystem warming at twice the global average and experiencing rapid resource development. We assess the focal or ‘umbrella’ value of the boreal population of woodland caribou for conservation of mammalian and avian richness (n = 432) in the boreal region of Canada by (i) evaluating co-occurrence of caribou distribution with that of boreal mammals (n = 102), birds (n = 330), at-risk mammals (n = 11) and at-risk birds (n = 47); and (ii) conducting systematic conservation planning using MARXAN software to identify minimum representative and complementary reserve networks, comprised of planning units deemed large enough (10,000 km2) for persistence of terrestrial wildlife, both at the extent of boreal caribou distribution and the entire boreal region. While boreal caribou overlap with the range of 90% of boreal birds and mammals, area-efficient networks representative of boreal diversity focus on species-rich areas south of caribou distribution and other areas that contain relatively small-ranged species. A similar pattern occurs when the MARXAN analysis focused only on caribou distribution, i.e. representative networks are preferentially located on southern herd ranges. However, this situation differs markedly to include large areas within the distribution of caribou if anthropogenic footprint on the landscape is considered as a constraint on reserve design. Efforts to sustain boreal caribou offer considerable opportunities to conserve diversity of co-occurring mammals and birds, including areas of the relatively more disturbed caribou southern ranges that have irreplaceable value in an efficient and representative pan-boreal network of reserves. The high focal value of boreal caribou for animal diversity should be considered when making decisions and policy choices about how to best allocate conservation efforts across its extensive distribution.

Significance A replicated management experiment was conducted across >90,000 km2 to test recovery options for woodland caribou, a species that was functionally extirpated from the contiguous United States in March 2018. Recovery options were reductions of predators, reductions of overabundant prey, translocations, and creating fenced refuges from predators. Population growth was strongest where multiple recovery options were applied simultaneously. This adaptive management study was one of the largest predator-prey manipulations ever conducted and provided positive results for this endangered North American ungulate., Adaptive management is a powerful means of learning about complex ecosystems, but is rarely used for recovering endangered species. Here, we demonstrate how it can benefit woodland caribou, which became the first large mammal extirpated from the contiguous United States in recent history. The continental scale of forest alteration and extended time needed for forest recovery means that relying only on habitat protection and restoration will likely fail. Therefore, population management is also needed as an emergency measure to avoid further extirpation. Reductions of predators and overabundant prey, translocations, and creating safe havens have been applied in a design covering >90,000 km2. Combinations of treatments that increased multiple vital rates produced the highest population growth. Moreover, the degree of ecosystem alteration did not influence this pattern. By coordinating recovery involving scientists, governments, and First Nations, treatments were applied across vast scales to benefit this iconic species.

Global climate warming is causing reductions in the depth and duration of snow cover across much of the distributional range of threatened boreal woodland caribou (Rangifer tarandus caribou). Plasticity in group size and composition among gregarious ungulates likely reflects a response to a variety of proximate factors, including environmental conditions such as snow depth. Yet, longitudinal studies of social organization by ungulates in response to environmental conditions are limited. We used 11 years of aerial survey data to examine winter group size in a northern population of boreal woodland caribou in response to late-winter snow depth. We documented caribou social organization (size and types of groups) and annual variability in group size. We tested the hypothesis that group size increases with increasing snow depth. Most groups (61%; n = 456) were ≤ 5 animals; however, they only constituted 37% of the animals. Caribou were distributed among four types of groups, including solitary females, males only, females only, and mixed groups. Group sizes differed among group types. Mixed groups were both the most common and largest groups encountered in late winter. We found a positive relationship between snow depth and group size; however, there was no relationship between snow depth and the percentage of mixed groups. These caribou may form larger groups in winters with deep snow as a behavioral strategy to reduce energetic costs, predation risk, or both. Climate-induced decreases in late-winter snow depth will likely reduce group sizes in boreal woodland caribou. However, further work is required to understand if this change in social organization will affect the persistence of local boreal woodland caribou populations.

Unspoiled wildlands of boreal landscapes provide critical habitats for wildlife. With the increase in resource development across Canada's boreal zone, woodland caribou (Rangifer tarandus caribou) and grizzly bears (Ursus arctos) are at risk of population declines. We used 4 planning scenarios with variants of these in decision-support software Marxan to allocate potential conservation priority areas for caribou and grizzly bears in boreal wildlands of the Muskwa-Kechika Management Area in northeast British Columbia, Canada. For caribou and grizzly bears across their seasonal habitats, priority areas allocated to preserve connectivity of habitat patches maintained more intact high-value habitats, with moderate opportunity cost for resource development, than those allocated under other scenarios. In winter when high-value habitats of caribou tend to coincide with resource-rich areas, priority areas allocated to preserve areas that are more vulnerable to development maintained more intact high-value habitats with higher opportunity cost (therefore greater adverse economic consequences) than those allocated in areas with lower resource potential. In growing-season (non-winter) habitats of caribou and grizzly bears, allocating priority areas toward either more vulnerable or less vulnerable areas did not substantially affect patch and landscape characteristics of conserved habitats. Priority areas intended to avoid predation risk for caribou were not effective in maintaining intact high-value habitats for caribou in these undeveloped wildlands. Conserving connectivity would best maintain most intact habitats for both species across seasons; conserving habitats most vulnerable to development also would discourage future development outside of the conserved areas in winter habitats of caribou. Findings from these conservation planning scenarios have implications globally to other areas where sensitive species are threatened by pending resource developments.

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.

Human-driven habitat fragmentation is increasing worldwide, and consequently many wild populations are subdivided, isolated and reduced in size. These changes in population structure reduce dispersal among subpopulations, limiting gene flow, accelerating genetic differentiation, and reducing genetic diversity and effective population sizes. Habitat fragmentation is associated with a reduced ability for populations and species to respond to changing environments, exacerbating extinction risks. The Atlantic-Gaspesie population of woodland caribou (Rangifer tarandus caribou) is isolated and genetically differentiated from other populations in Canada. It has been declining dramatically during the last century and is now considered Endangered. From a management perspective, this population is considered as a single unit of ~ 80 individuals, but GPS telemetry suggests that three subgroups use separate geographical areas and show limited dispersal. In this study, we used 16 microsatellite loci to (1) quantify and compare the genetic diversity observed within the three subgroups of the Atlantic-Gaspesie population, (2) evaluate the extent of the spatiotemporal genetic substructure among them by assessing whether the fine-scale genetic structure differs between subgroups and if it has changed over 15 years, and (3) estimate their effective population size. We found no change in genetic diversity among/within subgroups over time. We detected genetic substructure among subgroups based on their geographical locations (Logan-Albert vs. McGerrigle) and found evidence that this substructure has increased in recent years. The effective population size of this population appears to have declined by 53% over the last 15 years and is now estimated at Ne = 16 individuals. Management plans and conservation actions should consider this spatial genetic substructure to prevent further decline of this endangered population.

Long-distance migrations by ungulate species are a globally imperiled natural phenomenon and conservation of them requires monitoring population vital rates. Satellite telemetry tracking is widely used for understanding the spatial distribution and movement of animals, especially migratory animals in remote environments. Recently, analytical methods have been developed to infer parturition events from movement data in multiple species that calve in isolation, but to date such methods have not been tested on animals that both migrate and spatially aggregate during calving. We applied two movement-based methods developed to infer parturition in nonmigratory woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) to 241 reproductive seasons spanning 6 years of GPS data from migratory barren-ground caribou (Rangifer tarandus granti J.A. Allen, 1902). We compared results from both methods to data from aerial surveys of collared females during the calving period. We found that each movement-based method had ∼80% overall accuracy to identify calving events, with interannual variation ranging from 61% to 100%. When we considered instances when the two analytical methods agreed on parturition outcome, the accuracy increased to 89% with an annual range of 73%–100%. Using these methods, we identified marked interannual differences in peak calving dates and higher parturition rates than previously reported for this caribou herd. The successful application of these analyses to a migratory, gregarious ungulate suggests a broader applicability of the methodology.

AIM: Population‐limiting factors represent the core of conservation biology. Because animal space use is affected by ecological constraints that can vary among populations, limiting factors might be revealed from intraspecific variation in home range size. We evaluated biogeographic variation in the home range size of woodland caribou (Rangifer tarandus caribou), a threatened species inhabiting the boreal forest, in relation to land cover, topography, snowcover and disturbance across the species’ range. LOCATION: Twenty‐five populations in Canada, spanning the contiguous boreal forest (an east–west extent of 4,400 km), including the southern fringe of the species’ range, adjacent to a broad region of extirpation. METHODS: We compiled the average annual home range size of adult female caribou (5–68 home ranges per population) and 18 putative predictor variables in each population range. We uncovered major gradients using principal components analysis and then evaluated models of home range size using multiple regression, with orthogonal variables representing vegetation, human disturbance and snowcover. RESULTS: Average home range size varied 28‐fold among populations (range: 312–8,838 km²). Home range area was most strongly and negatively correlated with anthropogenic disturbance in the population range (R² = 0.391), a variable in all seven top models (ΔAICc ≤ 5.99). Among populations, where human disturbance in the population range was low (≤10%), mean home range sizes consistently exceeded 1,400 km². Conversely, where human disturbance was high (>55%), especially at the species’ southern range margin, mean home range sizes did not exceed 1,500 km². MAIN CONCLUSIONS: In the boreal forest, female caribou may constrict their home ranges amid human‐caused disturbances. We speculate that smaller home ranges may lower the risk of encounter by predators, a key limiting factor. Among populations, smaller home ranges may serve as a signal of anthropogenic habitat loss.

Most woodland caribou (Rangifer tarandus caribou) populations are declining primarily because of unsustainable predation resulting from habitat-mediated apparent competition. Wolf (Canis lupus) reduction is an effective recovery option because it addresses the direct effect of predation. We considered the possibility that the indirect effects of predation might also affect caribou population dynamics by adversely affecting summer foraging behaviour. If spring and/or summer nutrition was inadequate, then supplemental feeding in fall might compensate for that limitation and contribute to population growth. Improved nutrition and therefore body condition going into winter could increase adult survival and lead to improved reproductive success the next spring. To test that hypothesis, we fed high-quality food pellets to free-ranging caribou in the Kennedy Siding caribou herd each fall for six years, starting in 2014, to see if population growth rate increased. Beginning in winter 2015–16, the Province of British Columbia began a concurrent annual program to promote caribou population increase by attempting to remove most wolves within the Kennedy Siding and the adjacent caribou herds’ ranges. To evaluate the impact of feeding, we compared lambdas before and after feeding began, and to the population trend in the adjacent Quintette herd over the subsequent four years. Supplemental feeding appeared to have an incremental effect on population growth. Population growth of the Kennedy Siding herd was higher in the year after feeding began (λ = 1.06) compared to previous years (λ = 0.91) and to the untreated Quintette herd (λ = 0.95). Average annual growth rate of the Kennedy Siding herd over the subsequent four years, where both feeding and wolf reduction occurred concurrently, was higher than in the Quintette herd where the only management action in those years was wolf reduction (λ = 1.16 vs. λ = 1.08). The higher growth rate of the Kennedy Siding herd was due to higher female survival (96.2%/yr vs. 88.9%/yr). Many caribou were in relatively poor condition in the fall. Consumption of supplemental food probably improved their nutritional status which ultimately led to population growth. Further feeding experiments on other caribou herds using an adaptive management approach would verify the effect of feeding as a population recovery tool. Our results support the recommendation that multiple management actions should be implemented to improve recovery prospects for caribou.

As global climate change progresses, wildlife management will benefit from knowledge of demographic responses to climatic variation, particularly for species already endangered by other stressors. In Canada, climate change is expected to increasingly impact populations of threatened woodland caribou (Rangifer tarandus caribou) and much focus has been placed on how a warming climate has potentially facilitated the northward expansion of apparent competitors and novel predators. Climate change, however, may also exert more direct effects on caribou populations that are not mediated by predation. These effects include meteorological changes that influence resource availability and energy expenditure. Research on other ungulates suggests that climatic variation may have minimal impact on low-density populations such as woodland caribou because per-capita resources may remain sufficient even in “bad” years. We evaluated this prediction using demographic data from 21 populations in western Canada that were monitored for various intervals between 1994 and 2015. We specifically assessed whether juvenile recruitment and adult female survival were correlated with annual variation in meteorological metrics and plant phenology. Against expectations, we found that both vital rates appeared to be influenced by annual climatic variation. Juvenile recruitment was primarily correlated with variation in phenological conditions in the year prior to birth. Adult female survival was more strongly correlated with meteorological conditions and declined during colder, more variable winters. These responses may be influenced by the life history of woodland caribou, which reside in low-productivity refugia where small climatic changes may result in changes to resources that are sufficient to elicit strong demographic effects. Across all models, explained variation in vital rates was low, suggesting that other factors had greater influence on caribou demography. Nonetheless, given the declining trajectories of many woodland caribou populations, our results highlight the increased relevance of recovery actions when adverse climatic conditions are likely to negatively affect caribou demography.

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 km2of 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.

1. Endangered species policies and their associated recovery documents and management actions do not always sufficiently address the importance of migratory behaviour and seasonal ranges for imperilled populations. 2. Using a telemetry location dataset spanning 1981–2018, we tested for changes in prevalence of migratory tactics (resident, migrant) over time, switching between tactics, shifts in seasonal space use including migration corridors, and survival consequences of migrant and resident tactics for 237 adult female endangered woodland mountain caribou in one population in western Canada. 3. Over more than three decades, the proportion of individuals displaying annual migration to the low elevation forested winter range declined from nearly 100%–38%. Correspondingly, there was a strong switch away from being migrant to being year‐round residents at high elevation. 4. These behavioural changes corresponded to abandonment of low elevation winter ranges in association with increasing levels of anthropogenic land uses, including forestry and oil and gas developments. Furthermore, there were no identifiable migration corridors to target for migratory route protection. 5. These shifts translated to lower survival rates, particularly for caribou demonstrating resident tactics, consistent with recent declines of the caribou population. That migrants switched to residency in their largely undisturbed summer range, despite lower survival, indicates maladaptive habitat selection consistent with recent patterns of mountain caribou extirpations. 6. Globally, endangered species policies and their associated recovery plans and management actions often do not explicitly consider the challenge of protecting migratory species. Effective conservation of migratory species requires protecting critical habitats needed for the entire life history of the species, including all seasonal ranges and migratory habitat.

A recurring challenge for resource managers and decision makers is quantifying the trade-offs associated with alternative recovery actions for threatened species. Structured decision-making approaches can help evaluate such complex problems by formalizing objectives and constraints into functions that quantify the benefits and costs associated with each action. Yet, many of the scientific tools necessary to implement structured decision making require extensive literature review and often involve complex algorithms that make them inaccessible to managers. To address these issues, we integrated available information and developed a decision-support tool that managers can readily use to compare costs and benefits associated with alternative recovery actions for threatened species. Our software can be used to quantitatively estimate and compare the costs and demographic benefits of recovery actions for an iconic threatened species, woodland caribou (Rangifer tarandus caribou). While we use caribou as a case study, our approach to developing this management tool is transferable to other threatened taxa. The tool consists of a generalized matrix population model that is parametrized based on information from the published literature or ongoing experiments. Users can input population parameters (e.g., population size and survival rates) or choose from pre-set caribou subpopulations to estimate changes to populations from implementing recovery actions. The tool estimates the trade-offs associated with seven alternative recovery actions: linear feature restoration (LFR), linear feature deactivation (LFD), maternal penning (MP), conservation breeding (CB), predator exclosure (PE), wolf reduction (WR), and moose reduction (MR). We demonstrate our software by comparing recovery actions for the East Side Athabasca River caribou subpopulation and discuss how this tool can be used under a structured decision-making framework. This case study suggests that our open-source tool can be useful to guide wildlife conservation decisions by explicitly estimating costs and benefits associated with recovery actions, which ultimately helps to bridge the gap between management and science via increased accessible application of current knowledge.

Where predation is a major limiting factor, it has been postulated that woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) reduce movements to minimize contact with predators and exhibit fidelity to seasonal ranges. We examined fidelity behaviour within season and among years of woodland caribou based on locations of 65 radio-collared individuals in British Columbia, Canada. We used average linear distances between all possible pairs of radiolocations of individuals to assess fidelity. Among-year interlocation distances were similar to within-season interlocation distances during summer, indicating that caribou did not shift their distribution during seasons when they were most vulnerable to predation. Among-year interlocation distances were significantly greater than within-season interlocation distances during both early winter and late winter, indicating that individual caribou shifted their distribution among winters. The amount that an individual's distribution shifted among winters varied among and within individuals over different years. During early winter this behavioural plasticity was correlated with snow accumulation, with individuals having greater interlocation distances in years with high snow accumulation. Our results indicate that site fidelity outside the calving season is unlikely solely influenced by predator avoidance. We suggest that seasonal shifts in the importance of limiting factors vary from predation in summer to food in winter. © 2006 NRC.

Habitat loss, fragmentation and alteration are frequently identified as important threats to biodiversity, inducing major changes in the structure and composition of species communities and the resulting interspecific interactions. North American woodland caribou (Rangifer tarandus caribou) populations suffer from habitat modifications and most are currently in decline. It has been suggested that the conversion of old-growth coniferous forests into early-seral stages has increased cervid abundances, which have, in turn, stimulated a numerical response of predator populations, ultimately threatening caribou populations via a habitat-mediated apparent competition mechanism. Using a long-term dataset (1984–2012) of the Atlantic-Gaspesie caribou population, we quantified changes in interspecific interactions triggered by apparent competition between moose (Alces americanus) and caribou via the responses of two incidental predators, coyote (Canis latrans) and black bear (Ursus americanus). We also documented calf recruitment rates and analysed temporal trends (last three decades) in this vital rate. Inter-annual variations in autumn calf recruitment were mostly affected by the proxy of regional abundance of coyotes, which was highly correlated with moose and black bear proxies of abundance. The increase in coyote abundance proxy in the Gaspesie Peninsula following anthropogenic habitat modifications seems to be the main mechanism responsible for the current decline in the Atlantic-Gaspesie caribou population. Our analyses revealed some impacts of habitat alteration and the complexity of the resulting trophic cascades.

Identifying habitat that is essential to the recovery of species at risk, known as critical habitat, is a major focus of species at risk legislation, yet there has been little research on the degree to which these areas are protected. Here, we first review the provisions for protecting critical habitat on non‐federal lands within Canada's Species at Risk Act (SARA). Next, we use the declining southern mountain population of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada as a case study to show that identification of critical habitat does not guarantee its protection on non‐federal lands. Our analyses show that 909 km2 of critical habitat identified on provincial lands were logged in 5 years after it was legally identified under SARA. Existing provincial legislation and policies have provided incomplete protection of caribou critical habitat, and Canada's federal government has yet to exercise authority under SARA that could protect these areas. In the absence of nondiscretionary protection under provincial legislation, a combination of alternative mechanisms, involving all levels of government, Indigenous people, and industry, will be essential to protect critical habitat and help recover species at risk.

Anthropogenic landscape disturbances are known to alter, destroy, and fragment habitat, which typically leads to biodiversity loss. The effects of landscape disturbance generally vary among species and depend on the nature of the disturbances, which may interact and result in synergistic effects. Western Canada's oil sands region experiences disturbances from forestry and energy sector activities as well as municipal and transportation infrastructure. The effects of those disturbances on single species have been studied and have been implicated in declines of the boreal woodland caribou (Rangifer tarandus caribou). Yet, the specific responses of the mammal community, and of functional groups such as prey and predators, to those interacting disturbances are still poorly known. We investigated the responses of black bear, grey wolf, coyote, fisher, lynx, red fox, American red squirrel, white-tailed deer, moose, caribou, and snowshoe hare to both natural habitat and disturbance associated with anthropogenic features within Alberta's northeast boreal forest. We used a novel community-level modelling framework on three years of camera-trap data collected in an oil sands landscape. This framework allowed us to identify the natural and anthropogenic features which explained the most variation in occurrence frequency among functional groups, as well as compare responses to linear and non-linear anthropogenic disturbance. Occurrence frequency by predators was better explained by anthropogenic features than by natural habitat. Both linear and non-linear anthropogenic features helped explain occurrence frequency by prey and predators, although the effects differed in magnitude and spatial scale. To better conserve boreal biodiversity, management actions should extend beyond a focus on caribou and wolves and aim to restore habitat across a diversity of anthropogenic disturbances and monitor the dynamics of the entire mammal community.

Boreal caribou (Woodland Caribou, boreal population; Rangifer tarandus caribou) is a prominent mammal at the heart of a decades-long conflict between a growing resource sector and the associated risks to biodiversity. We employed the ISO 31010 Bow-tie Risk Assessment Tool (BRAT) to evaluate the cumulative effects of anthropogenic and natural factors that may affect the risk of self-sustainability to the boreal caribou herds of Northeastern British Columbia. We used the BRAT to produce a visual synthesis of the cumulative effects causing the growth rate of boreal caribou herds to persistently fall below a level corresponding to a 60% chance of being self-sustaining (λ < 1.025). The BRAT diagram provided the basis for a quantitative Layers of Protection Analysis (LOPA) of risk probabilities for three caribou herds. We combined threat assessments from the Species at Risk Act recovery strategy (Environment Canada 2012) with data from published landscape experiments (e.g. restoration of seismic traces, maternal penning, and wolf culls) to parameterize the LOPA in three study areas. We report the implications of a combination of mitigation options versus current risk conditions, as well as the implications of uncertainty in threat prevention. Our analysis indicates that a combination of mitigation scenarios will best facilitate caribou herd recovery, that barriers preventing predation threats could also aid in recovery success, and that compensatory predation may account for a significant proportion of both adult and juvenile female mortality across different herds. We estimated the minimum annual cost for effective mitigation and recovery to be $CDN 224K within any of the study areas. Bow-tie diagrams are a flexible and quantifiable tool that can translate resource management solutions to the diverse audience involved in conservation decision-making: scientists, land managers, policy makers, and concerned stakeholders.

Canada, like many nations around the world, is struggling to find solutions to both climate change impacts and biodiversity loss. Given the enormity of these problems, opportunities to align government policy responses are highly appealing. In Canada's Boreal Forest biome there is a compelling case that conservation designations of large landscapes can help slow biodiversity losses, including of iconic threatened species like boreal woodland caribou (Rangifer tarandus caribou), while increasing the likelihood that massive stores of carbon in those landscapes will remain there. The Boreal Forest biome of Canada is estimated to hold a minimum of 208 billion tons of carbon. Only 11% of the total carbon stored in soils and vegetation in Canada is now within existing protected areas. At least 69 billion tons of carbon are stored in unprotected intact landscapes that support woodland caribou.

Mountain pine beetle (MPB) has become an invasive forest pest of mature pine in western North America as it spreads beyond its former endemic range. Management actions such as timber harvest can reduce the spread of MPB but may affect species of conservation concern like woodland caribou. Our goal was to inform MPB management within caribou ranges by exploring the impacts of MPB on caribou habitat-focusing on terrestrial lichens, an important winter food for caribou. We evaluated differences in lichen cover among four MPB management actions: timber harvest, wildfires, leaving MPB killed trees as-is, and single-tree cut-and-burn control. We found little evidence that leaving MPB killed trees as-is or controlling MPB using single-tree cut-and-burn impacted lichen cover. However, we found that lichen cover was lower in timber harvested and burned areas compared to intact undisturbed forest but only 10 to 20 years post-disturbance, respectively. Our results suggest that despite short-term reductions in lichen cover, using timber harvesting and prescribed burns to control MPB may balance management needs for MPB while maintaining lichen cover over time. However, using timber harvesting and prescribed burns to manage MPB is likely to have detrimental population-level effects on caribou by increasing the proportion of disturbed habitat and thus predators within caribou ranges. Among the four management actions that we evaluated, the cut-and-burn control program balances the need to limit the spread of MPB while also limiting negative impacts on caribou food. Our work addresses some of the challenges of managing competing forest and ecosystem values by evaluating the consequence of forest pest management actions on an important food resource for a species-at-risk.

Woodland caribou (Rangifer tarandus caribou) are reliant on Cladonia spp. ground lichens as a major component of their diet and lichen abundance could be an important indicator of habitat quality, particularly in winter. The boreal forest is typified by large, stand-replacing forest fires that consume ground lichens, which take decades to recover. The large spatial extent of caribou ranges and the mosaic of lichen availability created by fires make it challenging to track the abundance of ground lichens. Researchers have developed various techniques to map lichens across northern boreal and tundra landscapes, but it remains unclear which techniques are best suited for use in the continuous boreal forest, where many of the conflicts amongst caribou and human activities are most acute. In this study, we propose a two-stage regression modelling approach to map the abundance (biomass, kg/ha) of Cladonia spp. ground lichens in the boreal forest. Our study was conducted in Woodland Caribou Provincial Park, a wilderness-class protected area in northwestern Ontario, Canada. We used field sampling to characterize lichen abundance in 109 upland forest stands across the local time-since-fire continuum (2&ndash, 119 years-since-fire). We then used generalized linear models to relate lichen presence and lichen abundance to forest structure, topographic and remote sensing attributes. Model selection indicated ground lichens were best predicted by ecosite, time-since-fire, and canopy closure. Lichen abundance was very low (&lt, 1000 kg/ha) across the time-since-fire continuum in upland forest stands with dense tree cover. Conversely, lichen abundance increased steadily across the time-since-fire continuum in upland forest stands with sparse tree cover, exceeding 3000 kg/ha in mature stands. We interpolated the best lichen presence and lichen abundance models to create spatial layers and combined them to generate a map that provides a reasonable estimation of lichen biomass (R2 = 0.39) for our study area. We encourage researchers and managers to use our method as a basic framework to map the abundance of ground lichens across fire-prone, boreal caribou ranges. Mapping lichens will aid in the identification of suitable habitat and can be used in planning to ensure habitat is maintained in adequate supply in areas with multiple land-use objectives. We also encourage the use of lichen abundance maps to investigate questions that improve our understanding of caribou ecology.