Effects of cultivated vegetation on the diversity of spontaneous plant communities in residential green spaces

With rapid urban expansion and population concentration, the proliferation of residential developments has resulted in numerous fragmented urban “islands.” The green spaces within these areas are often subject to intensive management and high maintenance inputs, leading to excessive resource consumption and diminished ecological functionality. Spontaneous plants—naturally occurring herbaceous species that thrive alongside cultivated vegetation—play a critical role in forming structurally and compositionally diverse plant communities. These species not only enhance the biodiversity of urban green spaces but also improve their ecological service capacity. Although previous research has investigated various factors that influence the diversity of spontaneous flora in cities, the ecological impact of planted herbaceous vegetation—particularly its effects on interspecific connectivity and species diversity of spontaneous plants—remains underexplored. A deeper understanding of the community structure of spontaneous plants in residential green spaces is essential for developing low-maintenance, high-biodiversity, and sustainable urban landscapes, ultimately contributing to the improvement of urban ecological environments.This study examines 21 residential communities in the Zhengxiang District of Hengyang City, China, to assess how different types and configurations of planted herbaceous vegetation affect the composition, abundance, interspecific associations, and species diversity of spontaneous plants. Using a combination of random sampling and typical plot methods, we recorded spontaneous plant abundance and richness across these sites. Green spaces lacking planted vegetation were used as a control group for comparative analysis. Diversity indices were calculated to evaluate the response of spontaneous plant communities to different vegetation treatments. Our findings reveal that residential green spaces host a rich diversity of spontaneous plants, with occasional species greatly outnumbering both dominant and common species. The composition and spatial arrangement of cultivated vegetation significantly influence interspecific interactions and species richness among spontaneous plants, with occasional species being particularly sensitive to these changes. Notably, plots planted with Cynodon dactylon exhibited the highest diversity of occasional species, while mixed planting configurations led to marked declines in their diversity. Furthermore, the diversity of occasional species was closely linked to community similarity and stability, underscoring their pivotal role in shaping overall community dynamics.These results suggest that strategic selection of vegetation types and planting patterns can enhance the ecological performance of urban green spaces. Such insights provide critical guidance for biodiversity conservation and sustainable landscape design in residential environments. Incorporating spontaneous species into planting schemes may promote resilient, multifunctional ecosystems, offering valuable direction for policymakers, urban planners, and ecological designers aiming to optimize the ecological benefits of urban green infrastructure.