Urbanization threaten the pollination of Gentiana dahurica

Is urbanization a driver of aboveground biomass allocation in a widespread tropical shrub, Turnera subulata (Turneroideae - Passifloraceae)?

Plant biomass allocation is mainly affected by the environment where each individual grows. In this sense, through the rapid global expansion of impermeable areas, urbanization has strong, albeit poorly understood, consequences on the biomass allocation of plants found in this environment. Nevertheless, the comprehension of biomass allocation processes in urban shrubs remains unclear, because most studies of urban ecology focus on tree species. This is an important gap of knowledge because a great part of urban vegetation is composed of shrubs and their association with trees have positive impacts in urban ecosystem services. In this study, we explored the ecological and potential selective pressure effects of an urbanization gradient on the biomass allocation patterns of aboveground organs of Turnera subulata, a widely distributed tropical shrub. We have demonstrated that, for certain reproductive organs, biomass allocation decreases in locations with higher urbanization. Unlike expected, the biomass of vegetative organs was not affected by urbanization, and we did not observe any effect of urbanization intensity on the variance in biomass allocation to vegetative and reproductive organs. We did not record urbanization-mediated trade-offs in biomass allocation for reproductive and vegetative organs. Instead, the biomass of these structures showed a positive relationship. Our data suggest that urbanization does not result in radical changes in biomass allocation of T. subulata, and neither in the variation of these traits. They indicate that the ability of T. subulata to thrive in urban environments may be associated with life history and morphological mechanisms. Our findings contribute to the understanding of shrub plant responses to urbanization and highlight urbanization as a potential factor in resource allocation differences for different structures and functions in plants living in these environments.

Plant-pollinator interactions in urban ecosystems worldwide: A comprehensive review including research funding and policy actions

Urbanization has rapidly increased in recent decades and the negative effects on biodiversity have been widely reported. Urban green areas can contribute to improving human well-being, maintaining biodiversity, and ecosystem services (e.g. pollination). Here we examine the evolution of studies on plant-pollinator interactions in urban ecosystems worldwide, reviewing also research funding and policy actions. We documented a significant increase in the scientific production on the theme in recent years, especially in the temperate region; tropical urban ecosystems are still neglected. Plant-pollinator interactions are threatened by urbanization in complex ways, depending on the studied group (plant or pollinator [generalist or specialist]) and landscape characteristics. Several research opportunities emerge from our review. Research funding and policy actions to pollination/pollinator in urban ecosystems are still scarce and concentrated in developed countries/temperate regions. To make urban green spaces contribute to the maintenance of biodiversity and the provision of ecosystem services, transdisciplinary approaches (ecological-social-economic-cultural) are needed.