Pollinators are facing global and regional declines. Building pollinator friendly urban green spaces is an effective way to mitigate the negative effects of urbanization on pollinator diversity and services. According to a new study by Wuhan Botanical Garden, Chinese Academy of Sciences and the College of Horticulture & Forestry Sciences of Huazhong Agricultural University in Urban Forestry & Urban Greening, selective planting of attractive flowering plants can improve the conservation value of urban greenspaces.

"Despite some studies proposing lists of pollinator-friendly plants for different countries and regions, the functional traits of flowering plants that influence pollinator preferences in urban green spaces require further investigation.” explains Dr. YE Zhongming from Wuhan Botanical Garden. In order to figure it out, researchers investigated various plant and floral traits, pollinator composition, and visitation frequency in a densely urbanized landscape in Wuhan, China, to examine the effects of green space area proportions and plant and floral traits on visitation frequency and analyze the preferences of different pollinator groups for plant and floral traits.

The results revealed that the flower shape, opening direction, and flower color significantly affected the preferences of pollinators. Lepidoptera preferred funnel-shaped and head-shaped flowers; Diptera preferred upward-facing yellow and orange head-shaped inflorescences; bees favored biennial and perennial herbaceous plants with disc-shaped, bowl-shaped, and flag-shaped flowers; solitary bees showed a preference for horizontally opened labiate or flag-shaped flowers.

The study also suggested that native woody plants (such as Nandina domestica, Thymus quinquecostatus, Lagerstroemia indica, and Tamarix austromongolica) and some non-native plants (such as Centaurea cyanus, Borago officinalis, Portulaca grandiflora, and Echinacea purpurea) contributed to enhancing urban pollinator diversity.

Due to the varying preferences of different pollinators, it is recommended to increase the flowering plants richness when designing pollinator-friendly gardens to promote overall pollinator diversity.

This work was supported by the National Natural Science Foundation of China.

Distribution map of research locations (Image by WANG Hui)

 Flower preferences of different pollinator groups (Image by WANG Hui)