Objective Long-term research on the impact of snow disasters in southern China on temporal β-diversity in subtropical primary evergreen broad-leaved forests remains limited. This study aimed to investigate the effects of snow disasters on the characteristics, compositional patterns, and underlying drivers of temporal β-diversity in subtropical evergreen broad-leaved forests, thereby providing a scientific basis for post-disaster forest recovery and ecosystem management.

Method A 4-ha permanent plot was established in Jiulian Mountain, Longnan City, Jiangxi Province, following the 2008 snow disaster. A re-survey of tree species composition, diameter at breast height (DBH), and tree height was conducted in 2022. Temporal β-diversity (including species turnover and species nestedness components) was calculated for different forest layers (dominant, sub-dominant, and understory) and spatial scales (20 m × 20 m and 40 m × 40 m) between the two surveys. Combined with topographic data and soil physicochemical properties, two-way ANOVA and mixed-effects-based hierarchical partitioning were employed to analyze the mechanisms by which abiotic factors (topography, soil physical properties and soil chemical properties) influence temporal β-diversity across forest layers and spatial scales.

Result (1) Forest layer significantly affected all β-diversity indices, while spatial scale significantly influenced both species turnover and nestedness components. Only the interaction between layer and scale significantly affected species turnover. At both 20 m and 40 m scales, species turnover dominated temporal β-diversity across all layers, with minimal contributions from nestedness. At the 20 m scale, temporal β-diversity and turnover increased sequentially from the dominant to the understory layer, whereas the nestedness component showed a successive decrease. (2) Among topographic factors, altitude significantly influenced the temporal β-diversity of the dominant layer at the 40 m scale. Among soil physical factors, bulk density significantly affected temporal β-diversity across all forest layers at the 20 m scale. Among soil chemical factors, phosphorus (P) and potassium (K) significantly impacted on the temporal β-diversity of the dominant layer at the 20 m scale. (3) At the 20 m scale, soil chemical factors contributed more to the temporal β-diversity of the dominant layer, while soil physical factors contributed more to that of the sub-dominant layer. At the 40 m scale, topographic factors contributed more to the temporal β-diversity and turnover across all layers compared to the 20 m scale. Soil physical factors significantly influenced the temporal β-diversity of the understory layer at both scales.

Conclusion Following the severe snow disaster, temporal changes in species composition in Jiulian Mountain’s primary evergreen broad-leaved forest were primarily driven by species turnover in the sub-dominant and understory layers, rather than by nestedness. Soil chemical and physical factors impacts respectively on the temporal β-diversity of the dominant and sub-dominant layers, respectively, while topographic factors played a more critical role at larger scales. Soil physical factors consistently impacted the temporal β-diversity of the understory layer. This study provides critical insights for post-disaster forest conservation and ecosystem management in subtropical primary evergreen broad-leaved forests.