Bumble bees (Bombus spp.) play an important role in the pollination of plants worldwide. In recent years, declines have been observed throughout North America, particularly in the Midwest. Many factors likely contribute to this decline, including the use of pesticides, disease, and habitat loss. Few studies have assessed the effects of grazing and cattle pasture, a common use for Midwestern grassland, on bumble bees. None, to our knowledge, have been conducted in North America or have compared cattle pasture to tallgrass prairie, a habitat thought to be optimal for requisite floral resources. In this study, we sought to determine what effects grassland management for cattle pastures and restored prairie have on the community composition of bumble bees at Midewin National Tallgrass Prairie in northeastern Illinois. Abundance, species richness, and diversity were recorded across 40 transects using standard sweep net protocol.
Results/Conclusions
We found a statistically significant effect of land use type on abundance, with over three times more bumble bees found in prairie compared to cattle pasture (t = 2.09, p = 0.0126). Species richness was 50% higher in prairie, but diversity was 50% higher in cattle pasture, although there was no statistically significant difference in either measure. These data provide a baseline for further study on land management practices and conservation of bumble bees in the face of habitat loss and decline across the Midwest.