Soil nutrients and vegetation along a karst slope gradient affect arbuscular mycorrhizal fungi colonization of roots rather than bulk soil AMF diversity

AimsSlopeposition affects soil nutrients and plant diversity, thereby altering arbuscular mycorrhizal fungi (AMF) communities. However, the effect of slope position on the relationship between plant diversity, soil nutrients, and AMF communities remains unclear.MethodsWe characterized soil physicochemical properties, plant diversity, and the colonization, diversity, and composition of AMF on the upper, middle, and lower slopes of karst shrub ecosystems.ResultsA lower slope increased the availability of soil nutrients such as available nitrogen, phosphorus, and potassium in the rainy and warm seasons. Slope position influenced AMF colonization and plant diversity. Specifically, plant richness was higher on lower and middle slopes than on upper slopes. AMF colonization intensity was higher on the lower and middle slopes than on the upper slope, and increased in the rainy and warm seasons compared to the that in the dry and cool seasons. Greater nodes and edges among AMF taxa caused more connection and complexity in the co-occurrence networks on lower and middle slopes than on upper slopes. The lower slope had relatively high available nutrients, soil thickness, and strong water capacity that improved plant growth, which in turn enhanced AMF colonization because of the mutually beneficial relationship between AMF and plants.ConclusionsOur results demonstrated that lower and middle slopes increase AMF colonization and interactions among AMF taxa by inducing plant growth with high diversity under rich soil nutrient conditions. Therefore, strengthening the colonizing strategies of AMF may substantially improve nutrient uptake and transfer during the recovery of abandoned agricultural lands.