How Introducing Flower Meadows in Cities Affect the Diversity of Plant-Bee Interactions
Abstract
Urbanization poses a significant threat to wild bee populations and the pollination services they provide, primarily due to habitat loss and fragmentation. To mitigate these challenges, initiatives such as establishing flower meadows in cities have gained prominence. One such initiative was the newly established Mother Meadow in Oslo city center. This study investigated the diversity and abundance of wild bees and their interactions with plants within the Mother Meadow, comparing the findings to data collected from pollinator-friendly habitats in the surrounding urban landscape. Despite the Mother Meadow exhibiting a lower diversity of wild bee species and unique plant-bee interactions compared to the surrounding landscape, it attracted a higher abundance of wild bees than the pollinator-friendly habitats in the surrounding areas. The spatially isolated Mother Meadow was predominantly visited by wild bee species with larger foraging ranges, such as bumblebees. This isolation can be a limiting factor for wild bee species richness, as species with smaller foraging ranges are less likely to reach the meadow. Despite its isolation the Mother Meadow may function as a steppingstone for wild bees from habitats on different sides of the inner Oslo fjord due to a general resource limitation of flowering plants in the city center. The Mother Meadow provided floral abundance for wild bees in the resource-limited environment and offered nutritional diversity by introducing plants occurring at lower frequencies in the surrounding landscape. An analysis of wild bees in the Oslo Meta Network showed that most of the observed species were common generalist species often observed in urban settings. Additionally, I found that wild bee communities and their interactions with plants were highly localized, indicating limited species movement between habitat fragments. The observed wild bees particularly favored blue-violet flowers with bilateral symmetry, late phenology, and high abundance, which has important implications for wild bee conservation in urban environments. My study provides a foundation for improving the establishment of future flower meadows to enhance wild bee diversity in urban and fragmented landscapes. It emphasizes the importance of implementing biodiverse and florally abundant meadows adjacent to other green areas to facilitate wild bee movement.