Introduction: Native bees are important for pollinating both native flowers and crops. Unfortunately, however, cropland is associated with low abundance and diversity of native bees. Nesting habitat and flowers are limited resources for native bees in agricultural landscapes so one way we can promote native bees in these habitats is to strategically manage the landscape to promote these resources. Nectar and pollen are the main food source for bees so high floral abundance should increase bee abundance. As for nesting, although most native bee species in Alberta nest below ground, many nest in deadwood and pithy plant stems which are abundant in treed crop borders, sometimes referred to as shelterbelts. Crop margins have been suggested in literature as nesting and foraging habitat for pollinators, so this may also be the case for roadside ditches.
Objectives: (i) Assess if treed crop borders and high roadside floral abundance and richness increase bee abundance and richness, and (ii) assess if roadside floral community composition changes the local bee community composition.
Methods: In the summer of 2025 blue vane traps were installed at 22 sites along Alberta single lane highways. Half of the sites were adjacent to treed crop borders while the other half were adjacent to herbaceous crop borders. Samples were collected every two weeks for a total of three sample rounds. Floral surveys were also conducted every two weeks. Bees were identified to species in the laboratory. A linear model conducted on log-log transformed bee and floral data was conducted to test the first objective. Direct, indirect, and constrained gradient analyses were used to determine bee-flower community associations.
Results: Crop border type, flower abundance, and flower richness did not affect bumble bee abundance or richness. Correlations between bumble bee species and flower species were significant but did not substantially contribute to the bumble bee community variation.
Conclusions: The remaining samples need to be sorted, identified, and analyzed statistically before any recommendations to landowners or roadside managers can be made.