Relationships between multi-scale factors, plant and pollinator diversity, and composition of park lawns and other herbaceous vegetation in a fast growing megacity of China

Green spaces are important refuges for biodiversity in urban areas, and lawns are one of the most widespread elements of urban green spaces globally. Chinese cities have adopted the use of lawns relatively lately and are currently experiencing a rapid increase in lawn area. In order to obtain knowledge and develop recommendations related to planning, design, and management of lawns in public parks, this study compared lawns with other three types of herbaceous vegetation in terms of plant and pollinator diversity and composition, using Xi'an City as a case study. Plants and pollinators were inventoried in 72 lawns, 12 perennial meadows, 15 Ophiopogon japonicus groundcovers, and eight Oxalis corymbosa groundcovers. Plant species diversity in lawns was positively associated with proportion of green space around lawns and lawn age, and negatively associated with frequency of use of chemical fertilizers. Proportion of native plant species in lawns was negatively associated with use frequency of chemical fertilizers and mowing frequency, and positively associated with irrigation frequency and lawn size. Pollinator species diversity is positively related to flowering plant species richness in all vegetation types. In order to enhance plant and pollinator species diversity, less mowing and chemical use on lawns are recommended. Future urban planning should also consider preserving and increasing the green area coverage within the city. Based on abundance and attractiveness to pollinators, several native herbaceous plant species have potential when creating alternative green spaces to lawns, but more studies are required to test their performance.