Naturalized honeybees are declining due to colony collapse disorder, and thus native bee communities are being given more attention. Members of the species-rich native genus, Lasioglossum, are important due to their ability to pollinate a wide variety of native and agricultural plants. To help with conservation of this genus it is important to look at how human impact on the land affects this bee. We examined the relationship between differing land use practices in southeastern Massachusetts and Lasioglossum abundance over two years (2016 – 2017). We sampled bees bi-weekly using pan traps and sweep netting, from April – July each year at six sites of varying land usage, including two sites that employed sustainable land-use practices comprised of no-mow zones, native landscaping plantings, and reduced chemical usage. We used ArcGIS to classify sites as urban or rural based on percent impervious cover within a 300-m buffer zone of each site.
Results/Conclusions
A clear distinction of characteristically urban (>30% impervious; three sites) and rural sites (<8% impervious; three sites) was supported by our ArcGIS analysis. A total of 2,268 individual bees of the genus Lasioglossum were collected and analyzed over two sampling seasons across all sites. Overall, Lasioglossum abundance declined 56% in pan trap collection, and 46% in sweep net collection from 2016 to 2017. Although this decline was statistically significant we will continue monitoring to assess whether this difference between two seasons is indicative of a longer-term trend. The most rural site (1.93% impervious, with no commercial farm present) had significantly higher average Lasioglossum abundance than all other sites. This suggests that particular resource(s) may be present at that site and lacking at the others, including those with sustainable land-use practices in place. The most urban site (46.85% impervious cover) had the lowest Lasioglossum abundance, which was significantly lower than the two other urban sites at which sustainable land-use practices were employed. Our results suggest that further investigation into the effects of sustainable land-use practices in both urban and rural settings is warranted. We plan to continue this line of inquiry by including more sites over additional seasons.