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

Species-at-risk conservation is complex and multi-faceted. However, mitigation strategies are typically narrow in scope, an artefact of conservation research that is often limited to a single species or stressor. The ability to research an entire community of strongly interacting species would greatly enhance our ability to forge more comprehensive and effective conservation decisions. We demonstrate how camera trapping and new statistical techniques can accomplish this using threatened boreal woodland caribou (Rangifer tarandus caribou; hereafter caribou) as a case study. Population declines in caribou are precipitous and well documented, but recovery strategies focus heavily on control of one predator (wolf, Canis lupus), with less attention on other known predators and apparent competitors. A multi-species conservation strategy is needed, but obtaining necessary data on multi-species densities has been prohibitively difficult. We used spatial count models, an extension of spatial-recapture models for unmarked populations, 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 (individuals/100 km2 ) ranged from 0.22 caribou (95% 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 coyote (95% BCI = 0.45-6.68) to 3.63 black bear (95% BCI = 1.25-8.52; the white-tailed deer model did not converge). Though wolf densities were higher than densities recommended for caribou conservation, we suggest that 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 important predators. We recommend a broader focus on the interacting species within a community when conserving species-at-risk. This article is protected by copyright. All rights reserved.