HABITAT USE AND SELECTION BY ADULT FEMALE MOOSE IN NORTHWESTERN MONTANA: VEGETATION TYPES, FOREST DISTURBANCE, AND THERMAL REFUGE

Abstract

We studied summer and winter habitat use and selection of 34 GPS radio-collared adult female moose (Alces alces) living in largely managed coniferous forests in the Cabinet and Salish Mountains in northwestern Montana during 2013-2022. We built resource-selection function (RSF) models at the 2nd and 3rd order scales, and supplemented them by examining functional response to resource availability. We also assessed whether habitat selection was influenced by ambient temperature and used independently obtained field data to gain insight about the abundance of 2 important dietary shrubs, Salix spp. and Ceanothus velutinus. Moose selected strongly for intermediate elevations, denser canopy cover, and riparian habitats, but against non-vegetated and pine-dominated stands. As expected given their preference for deciduous shrubs, moose selectively used cut stands after the initial decade post-timber harvest. We observed a subtle preference for uneven-aged versus even-aged treated stands. Although uncommon, burned areas were used by moose, particularly ~15-35 years post-burn when conditions were conducive for Salix spp. and C. velutinus. Moose made subtle adjustments in habitat selection based on time-of-day and the prevailing temperature, exhibiting behavior consistent with the hypothesis that they seek cooler microclimates to aid thermoregulation. To benefit moose, habitat management in these and similar systems should diversify forest structure by setting back succession through timber harvest and allowing fires where possible, while providing mature proximate coniferous canopy for thermal relief.