Wild bees along an urban gradient: winners and losers

TLDR

Bee community variability along urban gradients can strongly affect pollinator‑plant interactions. The study examined how bee species richness and community composition differ between city centre and suburbs in Poznań, Poland. Researchers recorded 2,495 bees from 104 species over 2006–2008 in Poznań. The survey found that Andrena haemmorhoa was most common, with other abundant species including Bombus pascuorum, Andrena vaga, Andrena nitida, and Bombus terrestris, and that species with small body size, later activity onset, and non‑solitary habits were favored in the city centre, yet overall bee diversity and richness remained stable across the urban gradient, indicating cities can support diverse bee communities and that conserving varied urban habitats is key.

Abstract

The variability of bee communities along an urban gradient has a potentially strong impact on pollinator-plant interactions. We investigated changes in bee species richness and community composition in the city centre and suburbs of Poznań, Poland. During 2006–2008 we recorded 2,495 individuals from 104 species. The most abundant species was Andrena haemmorhoa. Other abundant species were Bombus pascuorum, Andrena vaga, Andrena nitida, Bombus terrestris. Several species appeared to be more abundant in the city centre whereas others showed an opposite tendency. We have found that the urbanized landscape can act as a filter for the bee community since some specific ecological traits facilitate colonization of the city centre. Small-bodied species that start their activity later in the season and are not solitary preferred the city centre. However, bee species diversity and richness remained stable across the urban gradient indicating some advantages of being a city dwelling bee. We suggest that a city can be a very important habitat for a diverse bee fauna and that conservation of a wide range of habitats of different urbanization levels seems to be the most suitable strategy for conservation of bee diversity in cities.