Moose selection of canopy cover types related to operative temperature, forage, and snow depth

Abstract

Simple linear and muliple regressions were used to determine the contribution of operative temperature (T_e), forage, and snow depth to moose (Alces alces) selection of canopy cover types. The number of degree-hours for which T_e exceeded the thermal limit at which panting is required to dissipate metabolic heat contributed significantly to selection during summer (1 June – 15 September) and late winter (16 January – 15 April). Forage explained canopy cover selection in early winter (16 November – 15 January) and contributed significantly to the best equation describing habitat selection during late winter. Snow depth contributed to habitat selection in early winter but was not related to habitat selection during late winter. During summer, moose generally selected against sites where T_e exceeded 30 °C, the thermal limit requiring panting to dissipate metabolic heat. During late winter, moose also generally avoided canopy covers where T_e commonly exceeded 8 °C, the temperature at which panting is required to dissipate heat. During early winter, moose apparently suffered minimal heat stress, as T_e remained below 0 °C; consequently, moose selected canopy cover types that provided comparatively high forage availability.