Abstract: Under the background of biodiversity loss caused by urbanization, insect pollinators worldwide are facing severe survival crisis. Urban green spaces play an important role in maintaining pollinator biodiversity due to their diverse habitats and plant species. Nectar and pollen plants, which serve as the primary food source for pollinators, are essential components of the pollination network. However, there is currently a lack of in-depth understanding of the pollination network structure in urban ecosystems. We attempted to construct a quantitative pollination network in urban green spaces. We analyzed the nectar and pollen plants, pollinating insects and their functional group composition, as well as the structure characteristics of the pollination network at the species and network levels. We described five characteristics of nectar and pollen plants: plant origin, life form, cultivation conditions, invasiveness, and horticultural traits. Additionally, the impacts of nectar and pollen plants with different characteristics on the network structure were also analyzed. We documented a total of 814 types of interactions between 204 nectar and pollen plant species and 141 pollinating insect species, with a total frequency of 4698 interactions. Ten key nectar and pollen plant species were successfully identified. The characteristics of nectar and pollen plants significantly affected the pollination network structure. Native plants, perennial herbs or shrubs, spontaneous plants or low-management intensity plants, and non-horticultural plants played a stronger stabilizing role in the network. This study confirms the effectiveness of using network analysis to make scientific decisions for urban biodiversity conservation. Our findings had important theoretical and practical significance for optimizing the configuration and management of nectar and pollen plants, enhancing the ecological benefits of urban green spaces, and promoting urban biodiversity conservation and sustainable development.

Key words: nectar and pollen plant, pollinating insect, ecological network, urban biodiversity, pollinator functional group