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Avoidance of roads has been demonstrated for many animal species, but little is known about the relationship between anthropogenic disturbance levels and the degree of avoidance by animals. We investigated the hypothesis that the strength of road‐avoidance behaviour increases with the intensity of the disturbance for a large, disturbance‐sensitive herbivore: the forest‐dwelling caribou Rangifer tarandus caribou. We assessed the behaviour of 53 global positioning system‐collared caribou monitored during the gradual modification of a highway over a 7‐year period, while controlling for potentially confounding factors. We studied caribou movements, resource selection and distribution before, during and after road modifications at multiple scales. We expected that the degree of avoidance would be positively related to road width, traffic density and the presence of active construction sites. The proportion of individuals that excluded the highway from their home range increased as highway modifications progressed. A lower proportion of caribou locations was found in a 5000 m road‐effect zone during and after highway modifications compared with before. Within that zone, caribou avoided habitat types that were selected at the home range scale. Caribou displayed higher movement rates in the vicinity of the highway, especially when traffic density was high. Our data support the hypothesis that avoidance of roads by large herbivores is positively related to disturbance intensity. Our results shed light on the behavioural mechanisms determining avoidance of human infrastructure by large herbivores, and suggest that increased human activity may affect behaviour at multiple scales. Conservation efforts in areas where roads are constructed or modified should be directed towards maintaining access to critical habitat resources, while also restoring habitat quantity and quality.

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and J.-P. Ouellet, Univ. du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, PQ, Canada, G5L-3A1. Á C. Dussault, Service de la faune terrestre et de l'avifaune, Ministère des Ressources naturelles et de la Faune du Québec, 880 Chemin Sainte-Foy, 2e étage, Québec, PQ, Canada, G1S-4X4.Understanding animal movements across heterogeneous landscapes is of great interest because it helps explain the dynamic processes influencing the distribution of individuals in space. Research on how animals move relative to shortrange environmental characteristics are scarce. Our objective was to determine the variables influencing movement of a large ungulate, the moose Alces alces, ranging across a boreal landscape, and to link movement behaviour with limiting factors at a fine scale. We assessed 7 candidate models composed of vegetation, solar energy, and topography variables using step selection functions (SSF) for male and female moose across daily and annual periods. We selected and weighted models using the Bayesian Information Criterion. Variables influencing small-scale movements of moose differed among periods and between sexes, likely in response to corresponding changes in the importance of limiting factors. Best models often combined many types of variables, although simpler models composed of only vegetation or topography variables explained male's movements during rut and early winter. Moose steps were observed in good feeding stands from summer to early winter for females and from spring to early winter for males, supporting other studies of moose habitat selection. From summer to early winter, females alternatively selected and avoided cover stands during day and night, respectively. Solar energy reaching the ground was important, particularly during late winter and spring, likely due to its effect on snow cover, air temperature, or plant phenology. Moose generally moved in gentle slopes and variable elevation, which may have increased their chances of finding high quality forage, or improved their search of suitable calving sites or mates. Our study revealed the great complexity and dynamic aspects of animal movements in a heterogeneous landscape. Analysis of animal movement provides complementary information to more static habitat selection analyses and helps understanding the spatial variations in the distribution of individuals through time.

1. Prey may trade off resource acquisition with mortality risk by using various habitat selection strategies. Empirical assessments have shown that the functional and numerical responses of predators to human disturbances are variable, yet spatial changes in predation risk by two predators have seldom been studied for prey occurring in human-modified landscapes. Using the boreal caribou Rangifer tarandus caribou -grey wolf Canis lupus -black bear Ursus americanus system in eastern Canada, we investigated whether responses of prey towards one predator could concomitantly increase risk of predation from another predator exhibiting a different foraging tactic. 2. We investigated trade-offs made by solitary caribou females and mothers accompanied by their calf during the period of highest calf vulnerability and compared the behaviour of mothers that would eventually lose their calf to predation to that of mothers whose calf survived until the following year. We modelled habitat selection using different metrics of forage based on field measurements and digital maps and developed empirical models of predation risk and prey behaviour using GPS data collected on both predators and prey. 3. Mothers accompanied by their calf seemed to compromise foraging opportunities for safety, as opposed to solitary females who showed no particular avoidance of areas used by predators. Although caribou mothers adopted selection strategies that could have protected their offspring from wolves, females that eventually lost their calf to predation selected for vegetative associations that were favourable to bears. 4. Synthesis and applications. We determined that mothers that most strongly avoided suitable wolf habitat were also those that most strongly selected suitable bear habitat, suggesting that by using antipredator strategies aimed at reducing predation risk from wolves, caribou exposed their offspring to increased predation risk from bears. This result is of paramount conservation value as bears were responsible for 94% of caribou calf kills in this system. In the short term, conservation efforts for boreal caribou may benefit from the management of bear populations by means of liberal hunting regulations or predator control. In the long term, however, these actions should be used in conjunction with the protection of potential calving areas away from cutblocks and roads.