Objective This study investigates the structure and diversity of soil fungal communities in Larix gmelinii var. principis-rupprechtii plantations along a latitudinal gradient and examines their environmental drivers, aiming to provide a scientific basis for plantation ecosystem management and forest health assessment.

Method This study focused on Larix gmelinii var. principis-rupprechtii plantations. Eight typical sampling sites were selected along a latitudinal gradient, with three plots established at each site. Soil samples were collected from three depths of 0−10 cm, 10−20 cm, and 20−30 cm in each plot. Soil physicochemical properties were measured, and soil fungal community composition was determined using high-throughput sequencing. The variation patterns of soil fungal community composition and diversity along the latitudinal gradient and their relationships with environmental factors were then analyzed.

Result (1) The soil fungal communities in Larix gmelinii var. principis-rupprechtii plantations were mainly dominated by Ascomycota and Basidiomycota, with Inocybe as a common dominant genus. The composition and relative abundance of dominant genera varied markedly among soil depths and sampling sites, indicating strong spatial heterogeneity in community composition; (2) Fungal alpha diversity showed no significant latitudinal trend, whereas beta diversity exhibited significant latitudinal differences (P < 0.01); both displayed different patterns of variation among soil layers; (3) Correlation and redundancy analyses showed that mean annual precipitation, mean annual temperature, altitude, stand canopy closure, pH, and total phosphorus were among the main driving factors shaping fungal community structure. The alpha diversity indices of soil fungi were mainly affected by soil water content, altitude, clay content, and readily available potassium. Soil fungi in the 0−10 cm and 10−20 cm layers were more sensitive to soil physicochemical factors than those in the 20−30 cm layer.

Conclusion Mean annual precipitation, mean annual temperature, altitude, stand canopy closure, soil pH, total phosphorus, soil water content, clay content, and readily available potassium were the main environmental factors driving the spatial variation in soil fungal community structure and diversity in Larix gmelinii var. principis-rupprechtii plantations, and also represented important drivers of their latitudinal differentiation. These findings provide a theoretical reference for understanding the latitudinal response patterns of soil fungal communities in Larix gmelinii var. principis-rupprechtii plantations and their underlying environmental driving mechanisms.