Diversity Patterns and Community Assembly Mechanisms of Spontaneous Plant Communities in Urban Wastelands: A Case Study of Shenyang, China

Urban wastelands provide important habitats for spontaneous plants and contribute substantially to urban biodiversity. However, how community assembly mechanisms shift during succession in response to changes in plant community composition and function remains poorly understood. This study investigated spontaneous plant communities in 11 representative urban wastelands in the central urban area of Shenyang, China. Functional trait-based analyses and null models were used to examine changes in functional diversity and community assembly processes across successional stages. A total of 232 spontaneous plant species from 45 families and 149 genera were recorded. Species α-diversity increased but did not differ significantly among successional stages, while β-diversity was primarily driven by species turnover. Functional dispersion (FDis) and community-weighted mean (CWM) showed no significant overall successional changes, and functional trait structures were generally consistent with random expectations, suggesting important roles of stochastic processes with trait-dependent assembly patterns. These findings provide a case study for understanding the assembly mechanisms of spontaneous plant communities in urban wastelands and offer a theoretical basis for urban biodiversity conservation and the construction of near-natural plant communities.