Bees provide critical pollination services. Bumblebees (Bombus spp.) are especially effective pollinators due to their morphological features, generalist foraging preferences, and ability to sonicate. Bombus loss has been linked to declines in local plant diversity, suggesting the presence of this genus may indicate a healthy ecosystem. We analyzed Bombus abundance across six sites to determine if differing land-use practices affected the bumblebee community. We characterized land-use by percent impervious cover using GIS analysis of a 300-meter buffer zone around each site. Two of our sites were on a college campus that employed sustainable land-use practices including no-mow zones, and a small, managed native meadow. We sampled bumblebees via sweep-netting over two seasons in 2016 and 2017.
Results/Conclusions
Our GIS analysis allowed for a clear distinction of rural sites (<8% impervious cover; three sites) and urban sites (>30% impervious cover; three sites, including the two on the college campus). Over the two sampling seasons we collected a total of 257 Bombus individuals. There was no significant effect of sampling year (2016 vs. 2017) on Bombus abundance, so we pooled data from both years. Kruskal-Wallace analysis revealed a significant effect of site on Bombus abundance, suggesting an effect of land-use. Pairwise comparisons showed that one urban site with implemented sustainable land-use practices had significantly higher Bombus abundance (six times higher) than one of the rural sites. This suggests that bumblebees may be well suited for urban environments and may be particularly responsive to sustainable land-use practices such as no-mow zones and native plantings. The urban environment’s higher abundance may also be due to the concentration of floral or habitat resources. Future studies are needed to investigate the exact environmental factors that promote bumblebee communities.