Authors: Egerer, Monika;

In cities, insect pollinators contribute to urban biodiversity and provide important ecosystem services including pollination. Urban gardens are social-ecological spaces where wild and cultivated plants coexist, and natural structures are implemented or remain. Through these habitat interventions in what may otherwise be a resource-poor landscape, gardens may support diverse pollinator assemblages. In this talk, I use the example of our research on wild bees in community gardens in Berlin and Munich, Germany, and the California Central Coast, USA, to discuss how these habitats can promote bee assemblages representing a wide range of life history strategies. Specifically, I show how functional traits of bees associate with management factors in gardens, and also how bee traits relate to landscape-level urbanization. Furthermore, I consider how findings of rare bee species in these gardens open questions around whether gardens in urbanizing landscapes are ecological sinks, or whether they can support species conservation. Although many mechanisms driving urban pollinator diversity remain unknown, our preliminary work on bee diversity and traits in relation to the urban environment provides practical insight into how city residents can actively contribute to pollinator conservation, and calls for future research on changes in pollinator diversity in cities.