Space‐use behaviour of woodland caribou based on a cognitive movement model

Abstract

Movement patterns offer a rich source of information on animal behaviour and the ecological significance of landscape attributes. This is especially useful for species occupying remote landscapes where direct behavioural observations are limited. In this study, we fit a mechanistic model of animal cognition and movement to GPS positional data of woodland caribou (Rangifer tarandus caribou; Gmelin 1788) collected over a wide range of ecological conditions. The model explicitly tracks individual animal informational state over space and time, with resulting parameter estimates that have direct cognitive and ecological meaning. Three biotic landscape attributes were hypothesized to motivate caribou movement: forage abundance (dietary digestible biomass), wolf (Canis lupus; Linnaeus, 1758) density and moose (Alces alces; Linnaeus, 1758) habitat. Wolves are the main predator of caribou in this system and moose are their primary prey. Resulting parameter estimates clearly indicated that forage abundance is an important driver of caribou movement patterns, with predator and moose avoidance often having a strong effect, but not for all individuals. From the cognitive perspective, our results support the notion that caribou rely on limited sensory inputs from their surroundings, as well as on long-term spatial memory, to make informed movement decisions. Our study demonstrates how sensory, memory and motion capacities may interact with ecological fitness covariates to influence movement decisions by free-ranging animals.

Seeking sanctuary: the neonatal calving period among central mountain woodland caribou (Rangifer tarandus caribou)

“…Furthermore, reducing fidelity as a predatoravoidance strategy is consistent with our observation of lower calving-range fidelity at higher seismic-line densities because these features are associated with increased risk of wolf encounters during the spring calving period (Whittington et al 2011). Ultimately, low range fidelity may have negative fitness consequences among caribou because spatial memory is integral to space-use decisions (Avgar et al 2015) and when ungulates are not familiar with their surroundings they can suffer from higher mortality (Forrester et al 2015) and reduced foraging efficiency (Merkle et al 2014). …”

“…It is likely that calving site and postparturition selection is driven by trade-offs in predation risk from multiple predators (Leblond et al 2016) and forage availability (Johnson et al 2001;Avgar et al 2015), but further analysis is needed to better understand these relationships. We predicted caribou with calves would avoid anthropogenic features and burns because of the association between these features and low neonatal calf survival Leclerc et al 2014), and because generally caribou avoid disturbances (Dyer et al 2001;Joly et al 2007;Vistnes and Nellemann 2008).…”

“…However, during the postparturition period, caribou in both herds selected burns at the herd-range scale, whereas Narraway caribou avoided burns but Redrock-Prairie Creek caribou selected burns at the home-range scale. Selection for burns was unexpected but may be explained by food resources playing a greater influence on space-use decisions than predator avoidance (Avgar et al 2015). Previous research has found that burns (5 years of age) have a high vegetation productivity (Schaefer and Pruitt 1991), which may meet the nutritional demands of caribou during pregnancy and lactation (Parker et al 2009).…”

Seasonal resource selection of woodland caribou (Rangifer tarandus caribou) across a gradient of anthropogenic disturbance

“…While the global model used a common set of variables, in most cases the coefficients associated with the model were range specific. Our models provide support for the theory of spatial segregation, whereby caribou avoid areas with high moose density and high predator encounter rates such as deciduous and mixed forests, naturally disturbed areas, and linear features (James et al 2004;Courtois et al 2008;Fortin et al 2008;Bowman et al 2010;Avgar et al 2015). Caribou select areas of "refuge" such as peatlands and conifer forests to forage and minimize predation risk (Rettie and Messier 2000;McLoughlin et al 2010).…”

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

“…These results are similar to those of Leech (2015), who showed that translocated caribou displayed inconsistent patterns of selection compared to native caribou. These differences may be driven by individual variability, heritability in selection strategies, and/or space-use patterns that result from long-term spatial memory associated with the home range of the source population (Avgar et al 2015).…”