Wed, Aug 04, 2021:On Demand
Background/Question/Methods
By 2050, over two-thirds of the human population is expected to live in cities, increasing urban land cover. Urban areas can support high bee diversity, particularly when managed to increase flower resources and otherwise weaken urban ecological filters. Backyard conservation programs support public land management in support of biodiversity and may contribute to mitigating negative urbanization effects on plant-pollinator networks. While urbanization is typically associated with less robust networks, higher habitat quality has been linked to increased foraging generalization and more robust networks in an urban setting. To study the impact of urbanization and land management on bee visitation networks in residential gardens, we conducted a community science program called Shutterbee to track plant-pollinator interactions in St. Louis, Missouri, U.S.A. One hundred and sixty-five program participants from the general public and the Audubon Society's Bring Conservation Home Program (BCH), were trained to conduct biweekly backyard photo surveys and submit their photos to iNaturalist. Urbanization was quantified via principle component analysis to encompass multiple co-varying factors along the urban to exurban environment (e.g, impervious surface, human population density, nocturnal artificial light). We tested for effects of BCH certification and level of urbanization on bee behavior and network structure.
Results/Conclusions In 2020, Shutterbee community scientists documented 5,791 bee visitations. Analyses of behavior for five common, large bee species (Apis mellifera, Xylocopa virginica, Bombus griseocollis, Bombus impatiens, and Bombus bimaculatus) demonstrated limited change in behavior in response to conservation or across the urbanization gradient. Non-native A. mellifera were more generalized at locations with higher conservation status, but native species exhibited no changes in behavior in response to conservation status. For example, foraging specialization by B. griseocollis increased with urbanization but was not influenced by BCH level. Our preliminary results suggest that the A. mellifera exhibits greater behavioral response to conservation efforts than native bees in this system. However, our analyses were restricted to generalist foragers in part due to low representation of more specialized species in our dataset, supporting prior studies that . Alternatively, some specialized species may be more challenging to photograph and therefore harder to correctly identify. We discuss changes in niche partitioning and network structure in response to urbanization and conservation status. These results shed light on the degree to which small-scale conservation efforts may weaken urban ecological filters and support more robust pollinator communities in human-dominated landscapes.
Results/Conclusions In 2020, Shutterbee community scientists documented 5,791 bee visitations. Analyses of behavior for five common, large bee species (Apis mellifera, Xylocopa virginica, Bombus griseocollis, Bombus impatiens, and Bombus bimaculatus) demonstrated limited change in behavior in response to conservation or across the urbanization gradient. Non-native A. mellifera were more generalized at locations with higher conservation status, but native species exhibited no changes in behavior in response to conservation status. For example, foraging specialization by B. griseocollis increased with urbanization but was not influenced by BCH level. Our preliminary results suggest that the A. mellifera exhibits greater behavioral response to conservation efforts than native bees in this system. However, our analyses were restricted to generalist foragers in part due to low representation of more specialized species in our dataset, supporting prior studies that . Alternatively, some specialized species may be more challenging to photograph and therefore harder to correctly identify. We discuss changes in niche partitioning and network structure in response to urbanization and conservation status. These results shed light on the degree to which small-scale conservation efforts may weaken urban ecological filters and support more robust pollinator communities in human-dominated landscapes.