Pollinators and urban riparian vegetation: important contributors to urban diversity conservation

Background Urbanization process around the world has not only changed the patterns of land use, but also fragmented the habitat, resulting in significantly biodiversity loss. Urban rivers, serve as one of the natural corridors in urban ecosystems, are of importance for urban ecosystem stability. However, few studies have been done to explore the relationship between vegetation and pollinators in urban river segments. In this study, two urban streams in the city of Chongqing were selected as the study area, riparian vegetation, butterflies and bees were investigated along all four seasons of a year to illustrate the spatial and temporal distribution patterns. Simultaneously, the ecological functions of the river corridor were analyzed. Result In this study, 109 plant species belonging to 95 genera of 39 families were recorded; the number of sampled species for butterflies and bees were 12 and 13, respectively. The temporal and spatial patterns of species diversity among vegetation, butterfly, and bee are different, but the trends of variation among them are similar between the two streams. Bees were found to be more closely correlated with native flowering plants in riparian zone, rather than with cultivated riparian vegetation. Conclusions The native riparian vegetation in urban rivers plays an important role in urban biodiversity conservation by serving as a corridor. This study provides data supporting the protection of the remaining natural patches and restoration of damaged habitats in the city. The survey has accumulated data on native riparian vegetation and pollinators in urban rivers.