Maria Cristina Gaglianone

Urbanization is one of the main drivers of anthropogenic transformation, reshaping the distribution and abundance of floral resources and, consequently, altering the composition and organization of bee-plant interaction networks. In this study, we evaluated how different characteristics of urban green areas associated with urbanization (i.e., the extent of surrounding paved surfaces, the number of tall buildings, and floral cover), affect the structure of bee-plant interaction networks across 12 urban green spaces in a medium-sized city immersed in an Atlantic Forest domain in the State of Rio de Janeiro, Brazil. We also determined how interaction beta diversity varied among all sampling sites. We recorded 1,138 interactions between 39 bee species and 75 plant species. In general, we observed that higher pavement cover reduced the number of interactions, connectance, and modularity, while floral cover promoted more frequent interactions. Moreover, we found that the most frequent visitors and floral resources were dominated by a few widespread species among urban areas, while interaction turnover among sites was largely explained by rewiring rather than species replacement. In contrast, urban features did not significantly influence the beta diversity of interactions among green areas, suggesting bee flexibility to stablish interactions in city. The findings underscore the key role of structural and resource heterogeneity in sustaining ecosystem services in cities and indicate that increasing floral cover implementing thoughtful urban landscape management can help mitigate negative impacts on plant-pollinators interactions.

A catalogação polínica pode auxiliar na investigação das plantas usadas na dieta de polinizadores de uma determinada região. Esse trabalho teve como objetivo descrever o pólen de espécies vegetais de importância para polinizadores presentes no campus da Universidade Estadual do Norte Fluminense Darcy Ribeiro, em Campos dos Goytacazes, RJ. A coleta de dados foi feita no entorno do prédio da Ecologia Experimental e nos principais plantios ornamentais de espécies arbóreas do campus. As espécies foram identificadas, coletadas, anteras retiradas, mantidas em ácido acético glacial, acetolisadas e preparadas lâminas em triplicata. Os grãos de pólen foram fotomicrografados, medidos e descritos quanto às principais características externas. Foram descritas 30 espécies vegetais das seis principais famílias botânicas em floração durante o período do estudo (fevereiro de 2023 a maio de 2024). O desenvolvimento deste trabalho poderá fornecer subsídios para a melhor compreensão das interações ecológicas entre visitantes florais e plantas nos ambientes urbanos.

Green areas are important environments in the urban landscape where many bee species can find essential resources, such as nectar, pollen, and nesting sites. However, few studies have evaluated the effects of urban green areas attributes on bee assemblages, mainly in the bees showing high forest dependence as Euglossini bees. These orchid bees are important pollinators in the Neotropical urban ecosystems, and the forest loss associated with urbanization can negatively affect euglossine communities. Here, we evaluated the role of urban green areas (UGAs) on euglossine assemblages and the abundance of dominant euglossine species. For this, we quantified different local and landscape attributes in twelve UGAs in Campos dos Goytacazes city, southeast Brazil. We expected a higher euglossine abundance in UGAs with a higher number of trees, diameter at breast height- DBH, and flower cover (%), and with a lower paved area (%), number of high buildings, and surrounding paving area (%). The euglossine males were sampled with three bait traps in each UGA. We sampled 2465 euglossine bees of four species. Eulaema nigrita Lepeletier, 1841 was the most abundant species (N = 1319; 53.5%), followed by Euglossa cordata (Linnaeus, 1758) (N = 1139; 46.2%). We found a positive effect of flower cover (%) on the abundance of these dominant euglossine species, highlighting the importance of floral resources in urban matrices, even for synanthropic species.