| During spring and summer of 2015, we studied habitat usage by bumble bees (Bombus spp.) across two areas burned by wildfire on the Eldorado National Forest in 2004. We conducted 966 survey visits to 495 plots, during which we captured, identified, and released 676 individuals of 12 Bombus spp. We examined bumble bee use of floral resources, abundance, and diversity in upland post-fire chaparral, burned forest, and riparian zones. Six species were found across both fire areas. Each fire also supported an additional three species not found in the other, even though the two areas had similar habitats and elevation, and were separated by only 25 km. Bombus abundance and diversity were significantly greater in riparian areas than upland habitats. Within upland chaparral, Bombus preferentially foraged on bear clover (Chamaebatia foliolosa), and largely avoided mountain whitethorn (Ceanothus cordulatus) and deer brush (Ceanothus integerrimus). The differential use of chaparral shrub species for foraging by Bombus species has management implications for post-fire land management, particularly the timing and use of mechanical and chemical treatments to discourage or remove chaparral, and the selection of chaparral patches for retention or removal. |