The importance of considering multiple interacting species for conservation of species at risk

Abstract

Conservation of species at risk of extinction is complex and multifaceted. However, mitigation strategies are typically narrow in scope, an artifact of conservation research that is often limited to a single species or stressor. Knowledge of an entire community of strongly interacting species would greatly enhance the comprehensiveness and effectiveness of conservation decisions. We investigated how camera trapping and spatial count models, an extension of spatial‐recapture models for unmarked populations, can accomplish this through a case study of threatened boreal woodland caribou (Rangifer tarandus caribou). Population declines in caribou are precipitous and well documented, but recovery strategies focus heavily on control of wolves (Canis lupus) and pay less attention to other known predators and apparent competitors. Obtaining necessary data on multispecies densities has been difficult. We used spatial count models to concurrently estimate densities of caribou, their predators (wolf, black bear [Ursus americanus], and coyote [Canis latrans]), and alternative prey (moose [Alces alces] and white‐tailed deer [Odocoileus virginianus]) from a camera‐trap array in a highly disturbed landscape within northern Alberta's Oil Sands Region. Median densities were 0.22 caribous (95% Bayesian credible interval [BCI] = 0.08–0.65), 0.77 wolves (95% BCI = 0.26–2.67), 2.39 moose (95% BCI = 0.56–7.00), 2.64 coyotes (95% BCI = 0.45–6.68), and 3.63 black bears (95% BCI = 1.25–8.52) per 100 km2. (The white‐tailed deer model did not converge.) Although wolf densities were higher than densities recommended for caribou conservation, we suggest the markedly higher black bear and coyote densities may be of greater concern, especially if government wolf control further releases these species. Caribou conservation with a singular focus on wolf control may leave caribou vulnerable to other predators. We recommend a broader focus on the interacting species within a community when conserving species.

Boreal predator co‐occurrences reveal shared use of seismic lines in a working landscape

“…These species additionally show individual responses to anthropogenic disturbances, though responses vary and further investigation is necessary to evaluate consequences for interactions. Results from this study highlight important considerations of the impact of predator management decisions, which may unintentionally alter the behavior of coexisting species (Burgar et al, ). The relationships observed in this study occur in the context of a landscape experiencing ongoing industrial development, offering insight into species coexistence patterns in the face of continuing anthropogenic landscape change.…”

“…When coyotes exist in high densities, they may be able to reduce competition through behavioral mitigations such as increased group size or fine-scale temporal partitioning, thus increasing the benefits of scavenging (Atwood & Gese, 2008. Coyote density (2.64/100 km 2 ) eclipsed wolf density (0.77) by threefold south of our study area (Burgar et al, 2018 detections, suggesting lower coyote relative abundance. Coyotes in this area may therefore be avoiding direct competition but benefitting indirectly via scavenging.…”

“…Relative to other species, wolves and black bears occur at high densities in the boreal forest (Burgar, Burton, & Fisher, ), and both select industrial linear features for easy travel, making them likely candidates for strong interspecific interactions in industrializing landscapes (Latham, Latham, & Boyce, ; Latham, Latham, Boyce, & Boutin, ). Although anecdotal evidence describes aggressive interactions between individual wolves and bears (Palomares & Caro, ; Rogers & Mech, ), we propose that spatiotemporal overlap at the daily scale may be consistent with facilitative interaction between the two.…”

Slowing down wolves to protect boreal caribou populations: a spatial simulation model of linear feature restoration

“…, Burgar et al. ), and in Quebec black bears ( Ursus americanus ) were the main predator for caribou calves (57.2% of 64 monitored calf deaths) (Pinard et al. ), reducing bear predation on caribou could contribute to stopping caribou decline.…”

Density‐dependent space use affects interpretation of camera trap detection rates

“…Camera traps are triggered by a temperature differential and movement across their detection zone, thus capturing images of warm‐blooded animals that pass by. Compared to traditional live trapping, camera trapping is less expensive and less invasive (Kucera & Barrett, ), and it can be used for the simultaneous collection of data on multiple species (Burgar, Burton, & Fisher, ; Tobler, Carrillo‐Percastegui, Leite Pitman, Mares, & Powell, ). This makes CTs very attractive to those wishing to conduct large‐scale, multispecies monitoring programs.…”