Floral trait diversity supports multiple pollination systems across urban habitats in one of the world's greenest cities

Green cities comprise a variety of habitats subject to different levels of anthropogenic pressure, ranging from completely unvegetated areas to vast green spaces such as linear parks. In this scenario, cities can support different ecological processes and ecosystem functions, which vary qualitatively and quantitatively between different habitat types along the urbanization gradient. Specifically, green spaces and ruderal plants can support pollination services in urban ecosystems, providing food resources (e.g., nectar, pollen, oil), reproduction supports (copulation sites), and nesting sites for pollinators. As a result, plant species and their floral resources are important for pollinator diversity and the maintenance of the ecosystem service of pollination in urban areas. This study assesses and compares the diversity of floral traits associated with pollination systems across three kinds of urban habitats, i.e. sidewalks, vacant lots, and ponds, in Campo Grande, Mato Grosso do Sul, Brazil, recognized as one of the greenest cities in the world by the Food and Agriculture Organization of the United Nations (FAO/UN). We found that most of the evaluated species had a similar set of floral traits, mainly related to entomophilous pollination. However, the three kinds of habitats that we analyzed differ regarding the flowers' color and size, as well as the predominant pollination system. Consequently, the variety of urban habitats may play a crucial role in supporting diverse pollination systems, particularly generalist ones, which are essential for providing resources to a wide range of flower-visiting taxa and functional groups. In fact, the plant species in urban habitats tend to be taxonomically and functionally complementary, showing the importance of conserving the flora in different environments in the urban matrix, thus maintaining a higher pollinator diversity.