Wildlife habitat enhancements for grizzly bears: Survival rates of planted fruiting shrubs in forest harvests

• A. alnifolia had the highest overall survival rate over two growing seasons.
• S. canadensis and V. membranaceum may be more effective in the long term.
• Soil nutrient amendments reduced survival, whereas exclosures increased survival.
• Changes in survival with elevation were inconsistent with expected niche spaces.

Productive grizzly bear foraging habitats are lost as the prevalence of natural forest openings declines. We assessed the effectiveness of using wildlife habitat enhancements to increase food supply for grizzly bears in recent forest harvests by conducting planting trials of containerized shrub seedlings for three important late-season grizzly bear foods (fruiting shrubs): Shepherdia canadensis (Canada buffaloberry), Vaccinium membranaceum (mountain huckleberry), and Amelanchier alnifolia (saskatoon). We monitored seedling survival over two growing seasons and considered the effects of soil nutrient amendments, exclosures, initial seedling condition, and environmental factors (elevation and terrain). A. alnifolia had the highest survival rate, although it may not be as effective in the long term due to being preferred ungulate winter browse. Soil nutrient amendments reduced survival rates of all three species, perhaps due to competition with grasses, whereas exclosures increased survival rates. Survival rates across an elevation gradient for S. canadensis and A. alnifolia were inversely related to local occupancy rates, demonstrating that knowledge of their realized niche space is not consistent with early establishment rates of seedlings. As the amount of natural forest openings declines, wildlife habitat enhancements in disturbed sites with open canopies, including forest harvests, have the potential to locally increase late-season food supply for grizzly bears.