Abstract Detail


Davis, Cheyenne [1], Fogel, Nina [2], Buehrle, Emily [3], Felton, Josh [4], Clones, Jessica [3], Camillo, Gerado [2], Miller-Struttmann, Nicole [5].

Collaborating with Citizen Scientists to Examine the Effect of Area and Urbanization on Bee Diversity and Visitation Networks.

Urban green space (UGS) provides increasingly important habitats for pollinators as anthropogenic disturbances continue to expand. UGS has been established as an important sanctuary for wild bees. For instance, bumblebee foraging distance increased while colony number decreased with greater urbanization. Understanding the nuances of how UGS may support greater pollinator diversity and their services to their host plants will allow us to make more informed decisions regarding conservation efforts in urban ecology. Given the sixteen million hectares of lawn in the United States, conservation efforts that encompass “backyard conservation” have to potential to modify a significant proportion of UGS. Backyard conservation initiatives offer landowners the opportunity and support to increase biodiversity in their yards, potentially enhancing the quantity and quality of UGS in an area. Here, we collaborated with over 200 volunteers enrolled in the Shutterbee Citizen Science Program to survey bees in residential and community gardens in the St. Louis metropolitan area of Missouri and Illinois. Citizen scientists conducted bi-weekly photo surveys in a residential or community garden of their choosing in the summers of 2020 and 2021. Photos were uploaded to the Shutterbee Project on iNaturalist.org where the bee and plant were identified to genus by experts. We tested the effect of habitat size, quality, and urbanization on bee diversity and bee-plant network structure. We categorized gardens into three urbanization categories (exurban, suburban, or urban) based on impervious surface, human density, and woody cover. Using the iNEXT R package, we estimated richness, Shannon’s diversity, and Simpson’s diversity, and tested for the effects of urbanization, habitat quality, and area on bee diversity via regression analysis. Finally, we estimated bee-plant visitation network structure using the bipartite package in R Statistical Environment, and tested whether habitat size, quality, or urbanization category influenced modularity. Networks with higher modularity are more robust to perturbations and have sub-groups, known as modules, that consist of species more likely to interact within their module than outside of it. Preliminary analyses indicate that bee richness increased with garden size. However, network modularity did not change with area, suggesting that community structure and function remain consistent despite greater diversity in larger gardens. Modularity also did not differ with urbanization level. On the other hand, gardens located in suburban environments had higher bee richness relative to urban and exurban gardens, potentially due to increased nesting area relative to urban habitats and higher floral density compared to exurban habitats. Future analyses into the direct effects of habitat quality (e.g., area of exposed soil, flower density) on bee diversity will test whether these mechanisms contribute to the observed patterns. Taken together, these results are consistent with a proportional increase in both specialist and generalist bee foragers with garden area, regardless of the level of urbanization in the surrounding environment. Therefore, while larger gardens may support a greater diversity of bee species, they are unlikely to counter urbanization gradients that favor generalist foragers over specialist foragers.

1 - Webster University, Biological Sciences, 470 E Lockwood Ave, St. Louis, Missouri, 63119, United States
2 - St. Louis University
3 - Webster University
4 - Colorado College, Organismal Biology and Ecology, 14 East Cache la Poudre St., Colorado Springs, Colorado, 80903, USA
5 - Webster University, 470 Lockwood Ave., St. Louis, MO, 63119, United States

Urban ecology
Plant-pollinator Interaction

Presentation Type: Oral Paper
Number: EC11005
Abstract ID:907
Candidate for Awards:None

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