Density-dependent habitat selection and consequences for fitness in a fluctuating ground squirrel population
A habitat map of our study site at the Rocky Mountain Biological Laboratory in Gothic, Colorado. Squirrels have access to five microhabitat types: Aspen forest, Dry Meadow, Spruce Forest, Wet meadow, and Willow community.
Standardized Manly resource selection ratios for golden-mantled ground squirrels at two spatial scales: where an individual chooses to place its home range, or the area needed for day-to-day activities (Second Order), and where within its home range it spends most of its time (Third Order). Everything above the dotted red line indicates positive selection.
Predictive models show that access to perches, from which golden-mantled ground squirrels can gain predator visibility, influences habitat selection. As the number of perches within a given space increases, preferred use of that space increases.
Golden-mantled ground squirrels hibernate over winter and, because our study site is at high elevation (2900 m), the summer active season is very short. Squirrels only have about 4 months to emerge from hibernation, find a mate, care for young, and then gain enough weight to have sufficient fat stores to be hibernation-ready again by the end of the season. Drawings courtesy of Elsa Cousins.