Objective The invasion of alien plants poses threats to the biodiversity and ecosystem stability in urban park green space. This study aimed to explore current status of alien plant invasion in different habitats within park green space and their interspecific relationship with native dominant and common species, providing a scientific basis for effective control and ecological safety management strategies.

Method This study was conducted in ten parks with widespread distribution of alien plants in Chaoyang District, Beijing. Using α-diversity, niche breadth, niche overlap, and interspecific association indices, we analyzed the diversity and niche breadth of alien invasive plants in different habitats, as well as the niche overlap and interspecific association between alien invasive plants and native dominant and common species.

Result (1) A total of 31 species of alien invasive plants belonging to 13 families and 24 genera were recorded in the grassland, woodland, and wetland habitats of park green space in Chaoyang District, Beijing, with the largest proportion belonging to the Asteraceae family. There were no significant differences in species diversity of alien invasive plants and native plants across different habitats. However, the species richness, species diversity measured by Shannon-Wiener index, and Simpson's dominance index of alien invasive plants were significantly lower than those of native plants in three habitats. (2) Taraxacum officinale had the largest niche breadth among the alien invasive plants in all three habitats, but its niche overlap with native dominant and common species was low. (3) The niche overlap and interspecific association between alien invasive plants and native dominant and common species were low in all three habitats, indicating weak interspecific competitive ability.

Conclusion Currently, the invasion of alien invasive plants in the park green space of Chaoyang District, Beijing, is relatively low, and the plant communities are in an unstable early succession stage with loose interspecific relationship and no stable structure formed. Therefore, it is necessary to strengthen the monitoring and management of alien invasive plants, optimize the herbaceous plant community structure, and improve its stability and resistance to invasion.