Bee Diversity Across Forest and Farm Habitats on Organic Tree Farms in Idaho: Evidence for Sustainable Farming Supporting Native Pollinators

We surveyed bee communities across an organic conifer tree farm landscape in northern Idaho to assess how managed forest–agriculture mosaics support pollinator diversity. Bees were collected from farm fields, adjacent conservation forests, and a pollinator garden between May and August 2024 using aerial nets and identified to species or morphospecies. In total, 94 bee species were recorded, representing a mix of ground-nesting (46%), cavity-nesting (37%), and social (17%) taxa. Bee richness was highest in farm fields (66 species), intermediate in forests (48 species), and lowest in the pollinator garden (35 species). Community turnover among habitats was substantial (Jaccard dissimilarity = 0.67–0.76; Bray-Curtis dissimilarity = 0.53–0.55), indicating distinct assemblages associated with each habitat type. Comparisons with regional datasets from Montana and Washington revealed moderate overlap (Jaccard = 0.22–0.24), suggesting that the Highland Flats farm supports a partly unique bee fauna within the Northern Rockies. Seven non-native bee species and nine species of conservation concern (five Osmia, four Bombus) were detected, with those of conservation concern taxa often visiting native Lupinus flowers. Most bee visits occurred on non-native plants, though native blooms contributed key seasonal resources. These findings demonstrate that organic tree farms with structurally diverse forests and managed floral resources can function as refugia for both common and at-risk bees in temperate forested landscapes.