Differences in Soil Fauna Communities and Vertical Heterogeneity Between Winter Pre-Sealing and Sealing Periods in Plastic Greenhouse Vineyards

When cold waves occur in winter, the entire vineyard greenhouse is completely covered with plastic film to improve heat insulation. However, differences in vertical stratification of soil faunal communities between pre-sealing (PSP) and sealing periods (SP) have not been fully quantified. We compared soil fauna communities and hydrothermal nutrient conditions between PSP and SP in standardized protected vineyards, sampling 0–10, 10–20, and 20–30 cm soil layers. Community traits were analyzed via paired Wilcoxon tests and mixed-effects models, while compositional differentiation was assessed using PCoA/PERMANOVA, NMDS/ANOSIM, and redundancy analysis with hierarchical partitioning. Soil fauna abundance decreased significantly in SP, with sharp declines in 0–10 and 20–30 cm layers, whereas the 10–20 cm layer showed minimal shifts. Taxon richness and alpha-diversity indices exhibited no consistent stage-specific variations. Inter-layer compositional differentiation intensified in SP, indicating enhanced vertical community stratification. Depth-specific analysis revealed the main drivers of community shifts: SOC and C: N in 0–10 cm, pH and C: N in 10–20 cm, and moisture and temperature in 20–30 cm. Overall, we observed layer-dependent shifts in soil microenvironments and faunal communities between PSP and SP, suggesting that soil depth should be considered in protected vineyard management.