Abstract:In Canada, boreal caribou (Rangifer tarandus caribou) are declining in numbers, in part due to increased predation by wolves (Canis lupus). One management option to reduce wolf–caribou interactions and thus protect caribou is to remove man‐made linear features (LFs), structures such as roads, trails, and cut lines, which are used by wolves as traveling paths. Linear features increase wolf traveling speed and could additionally facilitate wolf entry into caribou habitat. Our goal was to quantify the expected ef… Show more
“…First, we considered that an encounter occurred when a prey was within a 1km radius of a wolf, a distance within the detection range reported for wolves (Mech and Boitani 2003). This distance was also used in previous studies (DeMars et al 2016, Spangenberg et al 2019 and was similar to distances of 1.5 km chosen by Muhly et al (2010) and of 1.3 km considered by Whittington et al (2011). When both caribou and moose were within the detectable distance, wolves chose moose over caribou every time (Mech and Boitani 2003).…”
Landscape complexity can determine the population dynamics of interacting predators and prey. Yet, management plans are commonly developed from aspatial predictive models. This oversight may result in unexpected outcomes or the loss of opportunities to make spatial interventions that would increase a plan's effectiveness. The management of the threatened woodland caribou (Rangifer tarandus caribou), boreal population, provides an example of such shortcomings when using an aspatial approach. Currently, the most influential management recommendation is to maintain at least 65% of undisturbed forests in areas occupied by caribou populations, regardless of the spatial configuration of the forest cover. Using a spatially explicit individual-based model (IBM), we evaluated the effects of the spatial configuration of cuts and roads on the mortality of boreal caribou living in sympatry with wolves (Canis lupus) and moose (Alces alces), an apparent competitor. Starting with a real forest landscape, we created forest management scenarios of the specific spatial distribution of cuts (mosaic, small, or large agglomeration) with increasing disturbance levels. We then ran the IBM with simulated agents, representing individuals of the three species, moving according to movement rules determined from radio-collared individuals. We found that movement responses to land cover types and roads differed among species. For example, caribou and moose generally avoided areas close to roads, contrary to wolves. Those differences influenced the mortality of caribou agents, which not only depended on the levels of disturbance but also depended on the spatial distribution of cuts and roads. After controlling for disturbance level, wolves were more successful when forest management required an extensive road network resulting in relatively high habitat fragmentation. Caribou agents experienced lower mortality in landscapes with low densities of road and disturbance-related edges. The effect remained much stronger, however, for the level than the spatial configuration of human disturbances. Still, our IBM demonstrated how landscape management could be used to manipulate species interactions, with the intent of either increasing or decreasing predation rates on specific populations, depending on management goals.
“…First, we considered that an encounter occurred when a prey was within a 1km radius of a wolf, a distance within the detection range reported for wolves (Mech and Boitani 2003). This distance was also used in previous studies (DeMars et al 2016, Spangenberg et al 2019 and was similar to distances of 1.5 km chosen by Muhly et al (2010) and of 1.3 km considered by Whittington et al (2011). When both caribou and moose were within the detectable distance, wolves chose moose over caribou every time (Mech and Boitani 2003).…”
Landscape complexity can determine the population dynamics of interacting predators and prey. Yet, management plans are commonly developed from aspatial predictive models. This oversight may result in unexpected outcomes or the loss of opportunities to make spatial interventions that would increase a plan's effectiveness. The management of the threatened woodland caribou (Rangifer tarandus caribou), boreal population, provides an example of such shortcomings when using an aspatial approach. Currently, the most influential management recommendation is to maintain at least 65% of undisturbed forests in areas occupied by caribou populations, regardless of the spatial configuration of the forest cover. Using a spatially explicit individual-based model (IBM), we evaluated the effects of the spatial configuration of cuts and roads on the mortality of boreal caribou living in sympatry with wolves (Canis lupus) and moose (Alces alces), an apparent competitor. Starting with a real forest landscape, we created forest management scenarios of the specific spatial distribution of cuts (mosaic, small, or large agglomeration) with increasing disturbance levels. We then ran the IBM with simulated agents, representing individuals of the three species, moving according to movement rules determined from radio-collared individuals. We found that movement responses to land cover types and roads differed among species. For example, caribou and moose generally avoided areas close to roads, contrary to wolves. Those differences influenced the mortality of caribou agents, which not only depended on the levels of disturbance but also depended on the spatial distribution of cuts and roads. After controlling for disturbance level, wolves were more successful when forest management required an extensive road network resulting in relatively high habitat fragmentation. Caribou agents experienced lower mortality in landscapes with low densities of road and disturbance-related edges. The effect remained much stronger, however, for the level than the spatial configuration of human disturbances. Still, our IBM demonstrated how landscape management could be used to manipulate species interactions, with the intent of either increasing or decreasing predation rates on specific populations, depending on management goals.
“…To date, the majority of studies assessing the potential impacts of seismic line restoration on caribou have been simulation‐based (e.g. Serrouya et al., 2020; Spangenberg et al., 2019; Yemshanov et al., 2019), and empirical assessments of restoration effectiveness remain rare (but see Tattersall et al., 2020a).…”
The restoration of habitats degraded by industrial disturbance is essential for achieving conservation objectives in disturbed landscapes. In boreal ecosystems, disturbances from seismic exploration lines and other linear features have adversely affected biodiversity, most notably leading to declines in threatened woodland caribou. Large‐scale restoration of disturbed habitats is needed, yet empirical assessments of restoration effectiveness on wildlife communities remain rare.
We used 73 camera trap deployments from 2015 to 2019 and joint species distribution models to investigate how habitat use by the larger vertebrate community (>0.2 kg) responded to variation in key seismic line characteristics (line‐of‐sight, width, density and mounding) following restoration treatments in a landscape disturbed by oil and gas development in northeastern Alberta.
The proportion of variation explained by line characteristics was low in comparison to habitat type and season, suggesting short‐term responses to restoration treatments were relatively weak. However, we found that lines with characteristics consistent with restored conditions were predicted to support an altered community composition, with reduced use by wolf and coyote, thereby indicating that line restoration will result in reduced contact rates between caribou and these key predators.
Synthesis and applications. Our analysis provides a framework to assess and predict wildlife community responses to emerging restoration efforts. With the growing importance of habitat restoration for caribou and other vertebrate species, we recommend longer‐term monitoring combined with landscape‐scale comparisons of different restoration approaches to more fully understand and direct these critical conservation investments. Only by combining rigorous multispecies monitoring with large‐scale restoration, will we effectively conserve biodiversity within rapidly changing environments.
“…Enhanced restoration of degraded seasonal ranges could also, over time, mitigate the current conservation challenge of habitat degradation (e.g. Ray, 2015; Spangenberg et al., 2019). Avoiding further extirpation of migratory caribou will only be possible if the full suite of landscape and habitat requirements for this species are affectively conserved in all seasonal ranges.…”
Section: Discussionmentioning
confidence: 99%
“…Moreover, early seral forage promoted by cutblocks enhances forage availability for moose and deer, leading to increases in primary prey abundance and subsequently, predator population growth (Seip, 1992; Serrouya, McLellan, Boutin, Seip, & Nielsen, 2011). Simultaneously, linear disturbances increase predator efficiency at searching for, encountering, and killing caribou (Spangenberg et al., 2019; Whittington et al., 2011). In response, caribou attempt to avoid anthropogenic disturbances, leading to indirect habitat loss, and yet are still often unsuccessful at predator avoidance.…”
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 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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