Urbanization effects on wild bee community assemblages and plant interactions

Monday, November 14, 2022

11:54 AM – 12:06 PM PT

Location: Vancouver Convention Centre, Meeting Room 116/117

Presenting Author(s)

AA

Anthony Ayers

York University
Toronto, Ontario, Canada

Co-Author(s)

Sandra M. Rehan

Associate Professor of Biology
York University
Toronto, Ontario, Canada

Urbanization is a major anthropogenic activity associated with environmental degradation and destruction, contributing to species declines across multiple taxa including bees. Therefore, elucidating bee response to urbanization is essential to promoting pollinator diversity in cities especially considering such landscapes are projected to expand substantially to support future global populations. To determine how bee community composition and plant-pollinator interactions are affected by urbanization, twenty-nine sites representing three urban categories (high, medium, and low urbanization) were monitored from May through September in Toronto, Canada. Bees were collected passively using pan and blue vane traps as well as actively using aerial nets and vacuums so that later analyses comparing community structure and plant-pollinator networks between urban categories could be performed, respectively. Functional traits such as lecty, behavior, nesting substrate, and native or invasive status were also recorded for species to examine whether such traits contribute to bee community assemblages. In total, 5,458 bees, comprising 26 genera and 163 species, were represented in this study. Landscape characteristics such as low percent tree cover and high impervious surface surrounding sites could explain the prevalence of ground-nesting and generalist species observed throughout the city. Additionally, floral resources remained largely consistent across the urban gradient, but plant-pollinator networks revealed floral host species dominating interactions within high, medium, and low urbanization levels. These results aim to broaden current understandings of urban bee ecology and influence urban policy decisions targeting pollinator conservation and informing ongoing efforts to restore wildlife habitats.