Habitat and Species Diversity of Spontaneous Plants on Both Sides of River Corridor in Chengdu Urban Area

River corridors are important habitats for the growth of spontaneous plants, but related studies are lacking. This research uses the uniform sampling method, along with the typical plot method, to select the Qingshui River, Nanhe River and Fuhe River that run through the northwest to the south of the urban area as the research samples, totally 223 plots. It analyzes the habitat types of spontaneous plants and the characteristics of the species composition, to provide a reference for habitat construction and landscape planning of spontaneous vegetation. The result shows that according to the distance from water, the habitats of spontaneous plants can be divided into three categories: waterside without revetment, revetment and on the shore. According to the different substrates and vegetation of green space, they can be categorized into 18 microhabitat types. In the northwest-south transect, the microhabitats of waterside vacant land, revetment wall, natural revetment and lawn are the most. Totally, 158 species of spontaneous plants belonging to 56 families and 121 genera are recorded, including diverse life forms. Among them, perennial plants are the most, amounting to 45 species. In terms of community diversity, the waterside habitat of the northwest-south transect is significantly higher than that of the revetment and shore, with significant differences among the microhabitats. However, there is no significant difference among the habitats in the city center. The influence of planted vegetation homogenizes the habitats significantly. In the planning of river corridors in the future, the existing spontaneous plant community of natural revetment should be retained as far as possible. The area with low interference should be protected, and ornamental flowers with low maintenance can be appropriately added in some communities.