Cultivated Vegetation Shapes Diversity and Stability of Spontaneous Herbaceous Communities in Residential Green Spaces

ABSTRACT Urban residential green spaces contribute to urban biodiversity by supporting both cultivated and spontaneous herbaceous plants, yet the effects of cultivated vegetation on spontaneous communities remain insufficiently quantified. Here, we investigated the composition, diversity, and stability of spontaneous herbaceous communities across 21 residential green spaces in Hengyang, China. A total of 145 spontaneous species were recorded, including 99 native and 46 non‐native species. Community composition was strongly dominated by occasional species (119 spp.), far exceeding dominant and common species. Cultivated vegetation significantly influenced community diversity, with effects varying among vegetation types. Higher diversity was observed in plots without cultivated vegetation and those dominated by Cynodon dactylon , whereas plots dominated by Ophiopogon japonicus and mixed vegetation exhibited reduced diversity. Seasonal variation in diversity also depended on vegetation type, with significant spring‐autumn differences detected only in less intensively managed plots. Community dissimilarity and stability both varied across vegetation types and were more closely associated with species frequency structure than with total diversity. Dissimilarity decreased with increasing diversity of dominant and common species, whereas community stability was significantly related to the diversity of occasional species. These findings indicate that cultivated vegetation shapes spontaneous plant communities by altering species frequency structure and habitat conditions, with implications for biodiversity‐oriented design and management of residential green spaces.