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Dormant season livestock grazing reduces reliance on harvested feeds, but typically requires protein supplementation to maintain animal performance. Individual variation in supplement intake can impact animal performance; however, it is unknown if this variation leads to individual or herd-level effects on grazing behavior, resource utilization, and grazing impacts to native rangelands. To examine effects of protein supplementation on dormant season cattle resource use and, subsequently, post-grazing habitat conditions, we examined cattle grazing behavior, resource utilization and biomass removal of vegetation on a native rangeland in Montana. A commercial herd of 272 (yr 1) and 302 (yr 2) cows grazed a 329-ha rangeland pasture from November to January. Intake of a 30% crude protein supplement was measured for each individual. Five individuals within each of six age groups were equipped with GPS collars. Time spent grazing declined with supplement intake ([Formula: see text] = -0.05 ± 0.02; P < 0.01). Distance traveled per day had a positive asymptotic association with supplement intake ([Formula: see text] = 0.35 ± 0.09; P < 0.01). On average, resource utilization by cattle grazing dormant season forage decreased with terrain ruggedness ([Formula: see text] = -0.09 ± 0.03), but was unrelated to aspect, temperature and wind speed. Notably, we observed high individual variability in resource utilization for elevation, distance from supplement and water. A post-hoc analysis suggested that individual attributes (age, body weight, supplement intake) influenced cattle resource use. At moderate stocking rates, dormant season livestock grazing did not affect residual vegetation conditions (P values > 0.22). However, residual cover of forbs and litter increased with relative grazing intensity ([Formula: see text] = 1.04 ± 0.41; [Formula: see text] = 3.06 ± 0.89; P ≤ 0.05). In summary, high individual variability in grazing resource utilization of cattle suggests individual-level factors could be the dominant drivers in grazing behavior and landscape use., Competing Interests: The authors have declared that no competing interests exist.

Mountain environments are currently among the ecosystems least invaded by non-native species; however, mountains are increasingly under threat of non-native plant invasion. The slow pace of exotic plant invasions in mountain ecosystems is likely due to a combination of low anthropogenic disturbances, low propagule supply, and extreme/steep environmental gradients. The importance of any one of these factors is debated and likely ecosystem dependent. We evaluated the importance of various correlates of plant invasions in the Wallowa Mountain Range of northeastern Oregon and explored whether non-native species distributions differed from native species along an elevation gradient. Vascular plant communities were sampled in summer 2012 along three mountain roads. Transects (n = 20) were evenly stratified by elevation (~70 m intervals) along each road. Vascular plant species abundances and environmental parameters were measured. We used indicator species analysis to identify habitat affinities for non-native species. Plots were ordinated in species space, joint plots and non-parametric multiplicative regression were used to relate species and community variation to environmental variables. Non-native species richness decreased continuously with increasing elevation. In contrast, native species richness displayed a unimodal distribution with maximum richness occurring at mid-elevations. Species composition was strongly related to elevation and canopy openness. Overlays of trait and environmental factors onto non-metric multidimensional ordinations identified the montane-subalpine community transition and over-story canopy closure exceeding 60% as potential barriers to non-native species establishment. Unlike native species, non-native species showed little evidence for high-elevation or closed-canopy specialization. These data suggest that non-native plants currently found in the Wallowa Mountains are dependent on open canopies and disturbance for establishment in low and mid elevations. Current management objectives including restoration to more open canopies in dry Rocky Mountain forests, may increase immigration pressure of non-native plants from lower elevations into the montane and subalpine zones.