| Two goals of conservation in fragmented landscapes are protecting high quality patches of habitat and ensuring movement of individuals among these patches. I studied the movement behavior and habitat relations of forest-dependent sciurids in southeastern Alaska, where forests are fragmented by clearcut logging. I investigated the movements of red squirrels (Tamiasciurus hudsonicus) by translocating them and observing post-release travel paths. Red squirrels released in forests used microhabitat features allowing rapid, efficient, and inconspicuous travel (logs, open vegetation, low slopes, high shrub cover per stem) while maintaining proximity to arboreal escape routes. Releases in manipulated plots corroborated these patterns of microhabitat selection. At forest-clearcut edges, where microhabitat features squirrels prefer are contrasted against those they avoid, squirrels always entered forest. Thus, microhabitat preferences explained behaviors at habitat edges, and microhabitat manipulations improved habitat intended for movement. At a landscape scale, red squirrels were more likely to cross gaps created by clearcuts if the detour efficiency (distance home crossing gap ÷ distance via forested detour) was low, suggesting an ability to compare distances along alternate routes and travel costs or risks in different habitats. Red squirrels with low body mass and low territorial calling rates were more likely to cross clearcuts, where the probability of encountering conspecifics is low, suggesting marginal habitat could serve as movement habitat for territorial species. I examined variation in territorial calling, caching, and spacing behavior of red squirrels. Large Sitka spruce (Picea sitchensis) trees predicted high calling rates and midden use, while large conifers of any species predicted shorter home range movements. Thus, the abundance of high-energy spruce cones may determine the energetic feasibility of territoriality and larderhoarding, and cone abundance generally may determine spacing behavior. Finally, I investigated selection of den trees by northern flying squirrels (Glaucomys sabrinus). Most dens (≥73%) were in cavities, and 21% were at heights of ≤3 m, which likely reflects the importance of thermoregulation in this cool, wet region. Northern flying squirrels selected for snags and larger trees with disease or physical defects. Retaining small groups of such trees would ensure availability of denning structures after logging. |
