Assessing the impacts of urban beehives on wild bees using individual, community, and population-level metrics

Abstract

Several species of wild bees are in decline globally and the presence of managed honey bees is one of many proposed stressors on wild bee populations. However, there is limited knowledge of the impacts of honey bee hives on wild bees, especially in urban landscapes. We performed a field study to assess the associations between honey bees and wild bees within the Greater Toronto Area in Ontario, Canada. We measured relative abundance of honey bees, wild bee metrics (abundance, community composition, functional diversity, and body size), and floral resources (floral density and richness); we also calculated impervious surface at 500 m and 1 km for each of our sites. Our main findings were that increasing honey bee abundance was correlated with decreases in wild bee species richness and functional diversity, as well as two wild bee species' abundances and one wild bee species body size, out of many assessed. This research adds to the growing body of literature aiming to evaluate whether honey bees are a stressor on wild bees in urban landscapes, which will be valuable for informing conservation management practices and future research.

Insect ecology and conservation in urban areas: An overview of knowledge and needs

“…Recent studies, however, suggest that a focus on Apis honeybees does little to raise awareness of insect conservation generally (Smith & Saunders, 2016). The impacts of this practice on local pollinator communities are still poorly understood (Casanelles‐Abella & Moretti, 2022; Graystock et al, 2016; MacKell et al, 2023) and may negatively impact the richness, abundance and activity of wild bees, even in areas of A. mellifera 's native range (MacInnis et al, 2023; Ropars et al, 2019). More research is critical to understanding the impacts and potential misuse of honey bees as a conservation flagship species.…”

Leveraging Biodiversity Net Gain to address invertebrate declines in England

“…To date, sites delivered under early adopter BNG councils have primarily occurred "on site", i.e., within the footprint of the development (Rampling et al, 2023). Smaller areas of post-development green space, such as those within housing developments, will face high levels of anthropogenic disturbance including erosion by footfall, littering, over-management, colonisation by Invasive Non-native Species (INNS), nutrient enrichment from domestic animal waste, pesticide use, and high densities of managed beehives in urban environments (Coleman 1981;De Frenne et al 2022;MacKell et al 2023). Nutrient enrichment and pesticide use are of particular concern for invertebrates, and can have effects beyond the development site, with sealed surfaces creating run-off into sensitive water-dependent habitats, such as floodplain meadows or alkaline fens (Cook 2007;Manninen et al 2010;Bart 2022).…”