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Scale-dependent movement behavior of red squirrels (Tamiasciurus hudsonicus ) in logged landscapes.
Bakker, Victoria*,1, 1 University of California, Davis, Davis, CA
ABSTRACT- Movement of animals between reserves is a common goal of most conservation strategies, yet we know little about the factors influencing these movements. I investigated the movement behavior of the red squirrel (Tamiasciurus hudsonicus) at two spatial scales in logged areas of southeastern Alaska. To force decisions between specific micro-habitat features or landscape configurations, I released individuals off their home ranges, recording ensuing movements with direct observation, tracking spools, and radiotelemetry. Conditional logistic regression showed squirrels avoided micro-habitat features typically associated with clearcuts, such as high stem densities, and selected for those features characteristic of older forests, such as proximity to logs and trees. In another experiment, squirrels moved preferentially through plots in which favored features had been enhanced and always entered forests when released at forest-clearcut edges. Despite strong avoidance of micro-habitats associated with clearcuts, landscape-scale paths revealed more complex decision-making. Of 37 translocated squirrels, 16 crossed clearcuts to reach home. Squirrels were more likely to cross if the detour efficiency (distance across clearcut/distance via forested detour) was low, suggesting they have an ability to compare distance and predation risk along alternate routes. Additionally, smaller squirrels were more likely to cross clearcuts, where the likelihood of encountering territorial conspecifics was low. Research at multiple spatial scales was essential to understanding the movement behavior of this forest mammal.
KEY WORDS: movement behavior, gap-crossing, micro-habitat selection, Tamiasciurus hudsonicus