Land use change mediated associations among soil environmental factors, microbial networks, and soil multifunctionality: A case study of the Changchong River small watershed in Chaohu Lake

Land use change (LUC) is a core driver of soil ecological function dynamics, yet critical knowledge gaps persist regarding soil multifunctionality (SMF) variation across LUC types, the relative contributions of soil environmental factors, microbial traits to SMF, and key driver identification. Here, we focused on the Chaohu Lake basin (middle-lower Yangtze River), selecting three land use types (grassland, cropland, forestland) to characterize LUC impacts on soil microbial traits (diversity, network complexity and stability), physicochemical properties, mineral elements, and enzyme activities. We then quantified SMF via 26 indicators and identified its key drivers. During cropland-to-forestland conversion, soil properties and microbial community composition recovered toward the grassland state (while microbial diversity decreased), with phosphorus driving microbial communities. Microbial network complexity and stability recovered, though only bacterial network stability increased significantly. Grassland bacterial assembly involved both deterministic and stochastic processes (other land uses relied on stochastic processes), with total potassium as the core assembly driver. Cropland had the highest SMF, and the SMF of forestland recovered toward grassland levels, SMF drivers differed by soil layer . Notably, microbial network complexity emerged as a key microbial factor regulating SMF. Overall, forestland SMF recovered with reduced anthropogenic disturbance. This study fills Chaohu basin SMF and LUC gaps, clarifies the pivotal role of microbial network complexity and the soil-layer-specific differentiation of key SMF drivers, and provides empirical insights for formulating ecological policies to optimize regional land use patterns.