Disentangling Woodland Caribou Movements in Response to Clearcuts and Roads across Temporal Scales

Abstract

Although prey species typically respond to the most limiting factors at coarse spatiotemporal scales while addressing biological requirements at finer scales, such behaviour may become challenging for species inhabiting human altered landscapes. We investigated how woodland caribou, a threatened species inhabiting North-American boreal forests, modified their fine-scale movements when confronted with forest management features (i.e. clearcuts and roads). We used GPS telemetry data collected between 2004 and 2010 on 49 female caribou in a managed area in Québec, Canada. Movements were studied using a use – availability design contrasting observed steps (i.e. line connecting two consecutive locations) with random steps (i.e. proxy of immediate habitat availability). Although caribou mostly avoided disturbances, individuals nonetheless modulated their fine-scale response to disturbances on a daily and annual basis, potentially compromising between risk avoidance in periods of higher vulnerability (i.e. calving, early and late winter) during the day and foraging activities in periods of higher energy requirements (i.e. spring, summer and rut) during dusk/dawn and at night. The local context in which females moved was shown to influence their decision to cross clearcut edges and roads. Indeed, although females typically avoided crossing clearcut edges and roads at low densities, crossing rates were found to rapidly increase in greater disturbance densities. In some instance, however, females were less likely to cross edges and roads as densities increased. Females may then be trapped and forced to use disturbed habitats, known to be associated with higher predation risk. We believe that further increases in anthropogenic disturbances could exacerbate such behavioural responses and ultimately lead to population level consequences.

Effects of Road Density and Pattern on the Conservation of Species and Biodiversity

“…Such research studies further demonstrated that not only can the barrier-effects of roads be species-specific across multiple taxa [47,49,55], they can influence some individuals within a species more than others [48,54]. Such differences were related to gender [48,50], age and/or body size (with smaller individuals being more restricted; [54]), and life history stage (such as the breeding season; [48,50]).…”

“…One study highlighted that the barrier effects of roads are a particular concern for species that migrate, such as the pronghorn (Antilocapra Americana) [46]. Of the studies included in this review, nine identified the characteristics of road that influenced permeability, such as traffic volume [46][47][48], road width or the number of lanes [47,49], and road surface type. For the latter, five studies determined that paved roads impeded the movement of wildlife more than unpaved roads (including a number of species of reptiles and chimpanzees, Pan troglodytes) [47,[50][51][52][53].…”

“…Such differences were related to gender [48,50], age and/or body size (with smaller individuals being more restricted; [54]), and life history stage (such as the breeding season; [48,50]). For example, in Kibale National Park in Uganda female chimpanzees with dependent young were less likely to cross a high-traffic asphalt road than other troop members [50].…”

Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape

“…For example, roe deer (Capreolus capreolus) in southern Norway do not shift habitat use in response to predation risk during winter because they are constrained by other factors such as thermoregulation and starvation due to food limitation (Ratikainen et al 2007, Lone et al 2014. Determining optimal strategies in light of different trade-offs can be particularly challenging for highly mobile species that move across dynamic landscapes (Herfindal et al 2009, Beauchesne et al 2013. However, there is a general paucity of studies that have tested the landscape of fear model across dynamic environments involving highly migratory species at large spatial scales (tens to hundreds of thousands of square kilometers), probably due to logistical and technological challenges of working in such systems, particularly in open aquatic systems.…”

Spatial factors influencing northern mountain caribou (Rangifer tarandus) survival and distribution in the Telkwa Range

“…Alternatively, it is possible that selection is maladaptive and that areas with high 26-40 year old cutblock densities represent ecological sinks, where evolutionary cues and actual habitat quality diverge, resulting in poor habitat choices by caribou (Schlaepfer et al 2002). Maladaptive choices by caribou have been documented in numerous studies and are proposed as being a result of habituation, range fidelity, maternally learned selection strategies, or an inability of caribou to adjust to a rapidly changing environment (Faille et al 2010, Dussault et al 2012, Beauchesne et al 2013, Losier et al 2015.…”