Dominant species stability outweighs species asynchrony and diversity in regulating temperate forest regeneration

Climate change increasingly threatens forest regeneration by disrupting seedling dynamics, yet the stabilizing mechanisms underpinning these critical early life stages remain poorly understood. Using a 15-year seedling demographic dataset from a temperate forest in Northeast China, we quantified how vapor pressure deficit (VPD), snow depth, soil fertility, and neighboring tree density jointly influence the temporal stability of seedling survival and recruitment, and further disentangled the underlying stabilizing pathways mediated by dominant species stability, species asynchrony, and species richness. Our findings demonstrated that seedling temporal stability was associated more strongly with the degree of dominant species stability than with species asynchrony and richness. Seasonal drought (higher VPD) significantly reduced stability by weakening both dominant species stability and species asynchrony, while deeper snow enhanced stability by buffering climatic stress during winter. Dense neighborhood competition further decreased survival stability, whereas fertile soils suppressed asynchrony and reduced recruitment stability. These results indicate that the increasing seasonal drought in temperate forests may erode the compensatory mechanisms that maintain regeneration stability, while snowpack can serve as an important climatic buffer. Together, these findings highlight the pivotal role of dominant species in mitigating climate-induced stress during forest regeneration and underscore the importance of integrating stabilizing mechanisms into forest management and climate adaptation strategies.