Seasonal distribution, winter habitat selection and willow utilization patterns of the Shiras moose on the Mount Haggin Wildlife Management Area
Burkholder, Braden Osborn.
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Moose populations are difficult to manage as moose exist at low population densities compared to other ungulates and may use a variety of habitat types. Local knowledge is needed to effectively manage moose populations and limited research has been conducted recently in Montana. This study took place on the Mount Haggin Wildlife Management Area (MHWMA) in southwestern Montana to assist with the management of moose throughout southwestern Montana and establish a baseline for future research. The objectives of this study were to describe seasonal distribution patterns and habitat selection by adult cow moose, with an emphasis on habitat selection during the winter season, and to quantify patterns in willow browse utilization by moose in winter. To accomplish these objectives, I used data from GPS collars on cow moose to determine the basic habitat use patterns and covariates associated with winter habitat selection. Browse surveys of willow were employed to quantify browse utilization on the study area and to determine which environmental covariates were associated with moose browse utilization in winter. Cow moose on the study area were non-migratory and had small winter and summer home ranges. Moose strongly selected for willow cover types and habitat selection was associated with cover type, distance to conifer, distance to willow, and elevation; these relationships changed when snowpack conditions varied. Current browse utilization was low (~10%) and was associated with previously browsed willow, preferred willow species, and willow community width. Based on the habitat selection analysis, both willow and conifer communities were important to cow moose in winter and these results have management implications for habitat conservation and aerial survey methods. The browse utilization analysis showed that browse was notably heterogeneous and would require a large effort to sample browse utilization accurately. However, browse patterns were associated with habitat covariates and habitat managers should take these covariates into account when placing sites for monitoring of willow browse utilization. Overall, the moose population and willow communities around MHWMA appear to be in good health, but threats from climate change, predation, and the potential for overharvest may create population management challenges in the future.