Surface subsidence caused by coal mining activities generates diverse wetland ecosystems. These newly formed wetlands exhibit distinct environmental characteristics due to variations in subsidence age, resulting in divergent biological communities. While species adapt to environmental changes through specific functional trait combinations, the response of aquatic community functional diversity to environmental gradients across chronosequences of mining subsidence wetlands remains unclear. This study investigated 13 coal mining subsidence wetlands (1–18 years) of macrozoobenthos in Jining, China. Through seasonal monitoring, we analyzed functional traits along with taxonomic and functional diversity patterns. Initial-stage wetlands were dominated by medium-sized (63.9%) and tegument-respiring taxa, whereas late-stage wetlands exhibited a shift toward large-sized (43.9%) and gill-respiring groups. Both species richness and functional richness declined over time, with taxonomic diversity demonstrating greater sensitivity to subsidence age. Seasonal community variability was more pronounced in initial-stage wetlands (1–4 years post-subsidence). Despite increasing habitat heterogeneity with subsidence age, functional redundancy maintains ecosystem stability. The shared origin and developmental trajectory of these wetlands may constrain functional divergence. Current research predominantly relies on traditional taxonomic metrics, whereas our findings emphasize functional trait analysis’s importance for ecosystem assessment, which provides a theoretical framework for ecological restoration and biodiversity conservation in post-subsidence wetlands.

Coal-mining subsidence wetlands are post-industrial landscapes whose sustainable management requires coordinated biodiversity monitoring across multiple taxonomic groups. We surveyed wetland plants and macrozoobenthos across nine coal-mining subsidence wetlands at three subsidence stages in China’s Jining Coalfield over three seasons. We evaluated cross-taxon congruence in α-diversity and community composition, together with environmental associations. Results indicated that plant species richness and Shannon–Wiener diversity were lower at the middle stage than at the late stage, whereas macrozoobenthos richness was higher at the late stage than at the initial and middle stages. Overall species richness was positively correlated between taxa, whereas stage- and season-specific congruence occurred only for Pielou’s evenness at the initial stage (negative) and Shannon–Wiener diversity in autumn (positive). Community composition varied among stages and exhibited significant cross-taxon congruence (p < 0.01). Environmental analyses indicated some shared associations but different overall response patterns between communities. Thus, the development of coal-mining subsidence wetlands involved asynchronous and context-dependent community reorganization rather than uniform cross-taxon convergence. These findings support stage-sensitive, multi-taxon monitoring to improve biodiversity assessment and provide a case-based reference for the science-based conservation, ecological restoration, and sustainable management of similar post-industrial wetland systems.