Dissertation Research: Drivers of community composition, species interactions, and gene flow in urban landscapes

动物为90%的植物物种授粉；因此，它们对维持健康的生态系统至关重要。在这些动物中，蜜蜂是野生植物最有效和最重要的传粉者之一，它们作为传粉者为农业系统提供的服务每年价值数千亿美元。除了我们熟悉的家养欧洲蜜蜂外，全世界至少还有2万种其他的野生蜜蜂。然而，由于人类造成的景观变化，包括城市化，许多野生蜜蜂种群的数量正在下降。这项研究探讨了城市景观如何改变城市中蜜蜂物种的类型，城市蜜蜂如何利用和授粉本地植物，以及不同大小的蜜蜂物种如何在城市地区移动。作为该项目的一部分，研究人员将向土地所有者提出建议，以促进健康的传粉昆虫群落。此外，该项目将通过雇用来自服务不足社区的大学和高中生作为研究助理，丰富科学界。本研究将采用网络分析方法探讨城市土地利用模式对植物-传粉媒介相互作用的影响。通过对蜜蜂访花的观察和对沿着城市化梯度（40个站点，城市覆盖率从0- 100%不等）收集的蜜蜂花粉多样性的检查，将开发城市梯度中的植物-传粉媒介网络。正如先前的观察表明，城市化地区的食物资源比农村地区少，研究人员预测，城市地区的蜜蜂可能会访问更多种类的花卉，而农村地区的蜜蜂可能会更专门地选择食物。为了研究城市景观中的扩散和定植模式，本研究还将研究两种密切相关的木蜂物种的基因组成。这些物种的筑巢行为相似，但大小不同，因此它们的扩散潜力不同。研究人员预测，体型较大的物种（Xylocopa virginica）将比体型较小的物种（Ceratina strenua）显示出更少的种群隔离（例如近亲繁殖）的遗传特征，因为它们可以在城市地区分散得更远。最终，这项研究的结果将有助于推断传粉媒介如何随着时间的推移在城市景观中持续存在。

Animals contribute to the pollination of 90% of all plant species; therefore they are essential for maintaining healthy ecosystems. Of these animals, bees are some of the most effective and important pollinators of wild plants and their service as pollinators to agricultural systems is worth hundreds of billions of dollars each year. In addition to the familiar domesticated European honeybee, there are at least 20,000 other species of wild bees worldwide. Many of these wild bee populations, however, are declining in number due to human-caused landscape changes, including urbanization. This research explores how urban landscapes alter the types of bee species found in cities, how urban bees use and pollinate native plants, and how different-sized bee species move through urban areas. As a part of this project, researchers will make recommendations to land owners to promote healthy pollinator communities. In addition, this project will enrich the scientific community by employing college and high school students from underserved communities as research assistants. The study will investigate the impacts of urban land use patterns on plant-pollinator interactions using a network analysis approach. The plant-pollinator networks across an urban gradient will be developed through observations of floral visits by bees and the examination of pollen diversity collected from bees found along a gradient of urbanization (40 sites ranging in urban coverage from 0-100 %). As previous observations indicate that urbanized areas contain fewer food resources than rural areas, the researchers predict that bees at urban sites may visit a greater variety of floral species, whereas bees in rural sites may be more specialized in their food choices. To investigate dispersal and colonization patterns within urban landscapes, this study will also examine the genetic make-up of two closely related carpenter bee species. These species are similar in nesting behavior, but vary in size and thus their dispersal potential. The researchers predict that the larger species (Xylocopa virginica) will show fewer genetic signatures of population isolation (ex. inbreeding) than the smaller species (Ceratina strenua) because they can disperse farther through urban areas. Ultimately, results from this study will allow inferences on how pollinators can persist in urban landscapes over time.