MODELING SEASONAL DISTRIBUTION AND SPATIAL RANGE CAPACITY APPROXIMATIONS OF MOOSE IN SOUTHEASTERN WYOMING

Abstract

Predictive maps of Shiras moose (Alces alces shirasi) habitat associations have not been created for most Wyoming populations. For the state's most recently established population in the southeastern mountains, a literature-based winter habitat suitability index (HIS) model was developed and assessed with locations of 23 moose wearing global positioning system (GPS) radio-collars in 2005-2006. Overall, the winter HSI model was poorly predictive of habitat occupancy. The relation­ship between individual utilization distributions and landscape variables was modeled with resource selection functions (RSF) during winter and non-winter periods. In winter, moose generally responded in a similar fashion to distance variables to riparian shrub, to deciduous forest and to forest edge, in addition to slope and slope2. Due to snow pack differences, 2 separate models were created for each winter; thermal aspect (warm vs. cool slopes) rather than slope and slope2 was more predictive in the winter of deeper snow. The non-winter model demonstrated the nearly exclusive importance of riparian shrub habitat in close proximity to forest cover across a wider range of elevations than during winter. Non-winter moose locations were best explained by the total area of riparian shrub patches within a surrounding 1 km radius. Distance to forest edge had a considerably stronger influence on non-winter habitat use. The association with deciduous forest was still significant, although less than during win­ter; slope was also explanatory. The models were validated and a spatial algorithm was employed to make rough carrying capacity approximations within the study area, based on the predicted RSF habitat quality and observed sizes of moose winter home ranges.