Multi-layer landscape design of urban spontaneous plant community: A case study in Zhengzhou, China

Climate change and rapid urbanization impose notable threats to urban biodiversity. Under the guidance of ecological concepts, spontaneous plants have quickly entered the field of landscape applications due to their advantages of low maintenance and high resistance. Until now, slope planting applications for spontaneous plants have been extremely scarce, especially in the hot and dry climate of northern regions. A multi-layer plant community design model was built based on spontaneous and ornamental plants to address this issue. Using the slope in Zhengzhou, China as a case study, a total of 72 spontaneous plant species from 108 surveyed quadrats were recorded, and the most prevalent families and genera were Asteraceae and Artemisia. Among them, 52 species (72 %) were identified to be native plants. The key microenvironmental factors influencing spontaneous plant growth on urban slope were humidity, slope aspect, and background materials. Adopting the hierarchical clustering method, the spontaneous plants were divided into eight distinct communities. In order to mimic the above-mentioned communities, after introducing the ornamental plants, the multi-layer plant landscape was constructed in the experimental area. Within the Community III we observed the highest mean coverage rate reaching to 71.4 %, whereas the Erigeron canadensis in Community I have the highest important value (0.35). Based on average importance value, and taking into account the factors affecting plant diversity and landscaping, Community II can be used as a priority for urban slope landscape design. Our study proposed a nature-based solution to alleviate the loss of urban vegetation and improve the entire slope ecosystem by incorporating spontaneous plants into landscape design strategies.