Impact of adjacent land use of bumblebee (Bombus spp.) abundance and diversity within small, manicured pollinator gardens

Native bumblebee (Bombus spp.) pollination enhances yields of fruit and seed crops; however, these pollination services are at risk with the decline of Bombus spp. in association with land conversion and loss of habitat. To counteract the decline, small pollinator gardens are being established across the country with a variety of native plants that bloom from May - October. These gardens have the potential to increase functional connectivity across fragmented landscapes, however, their impact on bumblebee success and crop pollination have yet to be determined. Here, several small pollinator gardens in southern Connecticut, whose adjacent land use in the surrounding 2 km buffers ranged from 8 - 83 % green space, were monitored for bumblebee workers from June-August. Individuals were captured and identified to species to quantify species diversity. Genetic samples were taken from Bombus impatiens individuals to quantify siblingship and approximate nest abundance. Furthermore, body size metrics were taken to infer worker health. We hypothesized that gardens situated within green buffers will support a larger diversity of bumblebee species, greater abundance of Bombus impatiens colonies, and larger body sizes than gardens surrounded by urbanization. Results from this work determine how landscape composition influences bumblebee space use for foraging, and will assist in providing guidelines for creating functional connectivity for bumblebees in fragmented landscapes.