A survey of the bees of Grand Staircase-Escalante National Monument, southern Utah: Incidence, abundance, and community dynamics

A survey of the bees of Grand Staircase-Escalante National Monument, southern Utah, was conducted over a period of four years. Six hundred and fifty-six species were discovered within the monument, including numerous range extensions, several new species, and three genera new to the state of Utah. This is the richest bee landscape studied to date; reasons for the high diversity include the large elevation gradient, the richness of flowering plants, many of which are limited in distribution and require specific pollinators, and the many small local populations of species. To test the significance of these features on patterns of bee incidence and abundance, several theoretically important landscape variables were measured. Landscape factors measured were chosen on the basis of their importance in previous studies of bee richness and abundance and their utility to land managers wishing to quickly assess the areas on a large landscape that may be hotspots of bee biodiversity. Specifically, elevation, percent sand, flowering species richness, landscape type, and habitat type were used. Flowering species richness was found to be the most significant predictor of bee richness and abundance, but landscape type also played a substantial role. Reasons for the differences in bee richness between landscape types may be because different landscape types had more abundant floral resources. Abundant perennial shrubs may also provide a more predictable resource. These results provide a foundation for future studies of bee communities in GSENM, and indicate the importance of long-term, spatially extensive sampling across a broad range of elevations and including numerous landscape types if bee faunas are to be fully documented.