Search

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 short-range 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. [ABSTRACT FROM AUTHOR]

It has been suggested that patterns of habitat selection of animals across spatial scales should reflect the factors limiting individual fitness in a hierarchical fashion. Animals should thus select habitats that permit avoidance of the most important limiting factor at large spatial scales while the influence of less important factors should only be evident at fine scales. We tested this hypothesis by investigating moose Alces alces habitat selection using GPS telemetry in an area where the main factors limiting moose numbers were likely (in order of decreasing importance) predation risk, food availability and snow. At the landscape scale, we predicted that moose would prefer areas where the likelihood of encountering wolves was low or areas where habitats providing protection from predation were dominant. At the home-range scale, we predicted that moose selection would be driven by food availability and snow depth. Wolf territories were delineated using telemetry locations and the study area was divided into 3 sectors that differed in terms of annual snowfall. Vegetation surveys yielded 6 habitat categories that differed with respect to food availability, and shelter from predation or snow. Our results broadly supported the hypothesis because moose reacted to several factors at each scale. At the landscape scale, moose were spatially segregated from wolves by avoiding areas receiving the lowest snowfall, but they also preferentially established their home range in areas where shelter from snow bordered habitat types providing abundant food. At the home-range scale, moose also traded off food availability with avoidance of deep snow and predation risk. During winter, moose increased use of stands providing shelter from snow along edges with stands providing abundant food. Habitat selection patterns of females with calves differed from that of solitary moose, the former being associated primarily with habitats providing protection from predation. Animals should attempt to minimize detrimental effects of the main limiting factors when possible at the large scale. However, when the risk associated with several potential limiting factors varies with scale, we should expect animals to make trade-offs among these. [ABSTRACT FROM AUTHOR]