Abstract: Aims Peat wetlands are globally significant carbon sinks and biodiversity hotspots, particularly sensitive to alien plant invasions. This study focuses on the subalpine peat wetland of Dajiuhu in Shennongjia, aiming to reveal the impact of the invasion of Erigeron annuus on the structure and diversity of plant communities, and to analyze its ecological effects and potential mechanisms. Medthods By setting up invasion and control plots, conducting plant community surveys, analyzing functional group composition and 11 soil factors, and integrating indicators such as α and β diversity, comprehensively assess the effects of invasion. Important findings The results showed that the invasion led to the decline of Poaceae and Juncaceae plants, while Asteraceae and Fabaceae plants expanded. The original dominant species in the invasive plots decreased and the abundance of community species was more uniformly distributed. With increasing dominance of E. annuus, Shannon diversity index, Pielou evenness index, and species richness of the invasion plots all decreased significantly, and the overall diversity level showed a substantial decrease. β diversity analysis showed that invasion significantly reduced species turnover rate and community spatial heterogeneity, leading to homogenization in species composition and functional structure. Soil environmental analysis showed that Erigeron annuus prefers low moisture and low nutrient habitats, possibly altering microenvironment conditions through plant-soil feedback mechanisms, further excluding wetland plants and affecting the direction of community succession. This study reveals the structural reorganization and functional degradation of subalpine peat wetland communities driven by E. annuus invasion, clarifies the necessity of establishing a long-term monitoring system and formulating targeted prevention and control strategies, and provides theoretical support for the management of subalpine peat wetland invasion.

Key words: Shennongjia, Dajiuhu, plant invasion, species diversity, species composition