Patterns and Drivers of Spontaneous Plant Diversity in Urban Wastelands Across 17 Cities on the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau (QTP) is ecologically significant due to its unique biodiversity and vulnerability to climate change and rapid urbanization. Among its emerging urban habitats, wastelands with relatively low anthropogenic disturbances offer key refuges and stepping stones for spontaneous plants. However, the patterns and drivers of spontaneous plant diversity in these habitats remain poorly understood. To address this, we surveyed spontaneous plant communities across 17 cities on the QTP. We found that native species dominated urban wasteland flora (85.8%), whereas invasive species constituted over half (65.8%) of the non-native species. The results showed that land-use legacy effects and environmental filtering shape community assembly. GLMM analyses further reveal that the climatic background constitutes a key factor shaping community diversity variations across the QTP, exerting the most significant influence on species richness, particularly through precipitation and wind speed. Urbanization and habitat quality factors jointly shape the diversity structural characteristics of communities. However, non-native and invasive species exhibit heightened sensitivity to local habitat quality. Furthermore, differences between communities across all groups were due to species turnover, though the driving factors differed between groups. Native species exhibited stronger overall ecological adaptability, whereas differences between communities of non-native and invasive species were primarily driven by human disturbance and habitat conditions. These findings underscore the ecological value of urban wastelands on the QTP for biodiversity conservation and invasion management under rapid urbanization and climate change.