Close encounters of the fatal kind: Landscape features associated with central mountain caribou mortalities

Abstract

In western Canada, anthropogenic disturbances resulting from resource extraction activities are associated with habitat loss and altered predator–prey dynamics. These habitat changes are linked to increased predation risk and unsustainable mortality rates for caribou (Rangifer tarandus caribou). To inform effective habitat restoration, our goal was to examine whether specific linear disturbance features were associated with caribou predation in central mountain caribou ranges. We used predation‐caused caribou mortalities and caribou GPS‐collar data collected between 2008 and 2015 to assess caribou predation risk within and outside of protected areas at four spatio‐temporal scales: habitat use during the (a) 30 days, (b) 7 days, and (c) 24 hours prior to caribou being killed, and (d) characteristics at caribou kill site locations. Outside of protected areas, predation risk increased closer to pipelines, seismic lines, and streams. Within protected areas, predation risk increased closer to alpine habitat. Factors predicting predation risk differed among spatio‐temporal scales and linear feature types: predation risk increased closer to pipelines during the 30 and 7 days prior to caribou being killed and closer to seismic lines during the 30 days, 7 days, and 24 hours prior, but decreased closer to roads during the 30 days prior to being killed. By assessing habitat use prior to caribou being killed, we identified caribou predation risk factors that would not have been detected by analysis of kill site locations alone. These results provide further evidence that restoration of anthropogenic linear disturbance features should be an immediate priority for caribou recovery in central mountain caribou ranges.

Beyond the encounter: Predicting multi‐predator risk to elk (Cervus canadensis) in summer using predator scats

“…We present a new method to quantify predation risk that incorporates where prey may encounter but also be killed. We found it produced predictions of predation risk comparable to those based on kill-sites, the most common approach to quantify the risk of mortality (Kauffman et al, 2007;McKay et al, 2021;McPhee et al, 2012;Miller et al, 2015).…”

Behavioral “bycatch” from camera trap surveys yields insights on prey responses to human‐mediated predation risk

“…Understanding trade‐offs between attraction to forage and avoidance of predators, and the spatial scales at which they occur, is fundamental to predicting species responses to caribou management actions, such as habitat restoration and predator control. Further investigation of direct measures of forage availability, resource selection, and mortality from predation is warranted for ungulates in this system (Darlington et al, 2022 ; Finnegan et al, 2018 ; McKay et al, 2021 ).…”

Optimal restoration of wildlife habitat in landscapes fragmented by resource extraction: a network flow modeling approach

“…The local access concept in our model is appropriate for tracking the capacity of caribou to utilize restored seismic lines. One of the goals of seismic line restoration is to reduce exposure to predation when caribou are close to disturbed sites (Whittington et al 2011; McKenzie et al 2012; Dickie et al 2020; McKay et al 2021). In our model, this required tracking the amount of undisturbed caribou habitat close to a restored node.…”

“…Seismic lines alter caribou habitat and facilitate incidental predation risk by increasing abundance of predators such as gray wolves (Canis lupus) (Serrouya et al 2020), thereby increasing their chance of a direct encounter with caribou (Whittington et al 2011;McKenzie et al 2012). A network of seismic lines increases the hunting efficiency of predators by allowing them to move farther and faster into caribou refuge habitat (Dickie et al 2017;Mumma et al 2017;McKay et al 2021). The creation of seismic lines also increases the amount of disturbed land with early successional vegetation, which in turn attracts more ungulates and their predators, while also decreasing the area of core intact habitat that can be used by caribou as a refuge (Schneider et al 2010;Latham et al 2011aLatham et al , 2011bWilson & DeMars 2015).…”