Uncovering the complex relationship between plant diversity, soil properties, and mycorrhizal inoculum potential in threatened Miombo woodlands

Abstract

AbstractArbuscular mycorrhizal fungi (AMF) are key members of soil microbial communities and play a key role in regulating ecosystem processes. However, the mutual interdependence of plants and AMF in threatened Miombo woodlands has not yet been fully elucidated. In this study, we investigated the relationship between plant ecological indicators and soil mycorrhizal inoculum potential (MIP) in the Miombo forest fallow of Haut‐Katanga, Democratic Republic of Congo, and identified plant species that positively influence soil MIP. We conducted a floristic inventory on 32 plots and collected soil cores for physicochemical and AMF characterization. Trap cultures using Crotalaria juncea seedlings were performed to determine the soil MIP. We also tested the AMF colonization status of randomly collected living roots of mature woody and dominant herbaceous species to identify explanatory variables for MIP. Our results showed that MIP was twice as high in silty clay soils (63.13%) than in clay soils (30%). Furthermore, MIP increased accordingly with the relative abundance of a group of woody and herbaceous species (e.g., Albizia adianthifolia, Baphia bequaertii, and Setaria pumila) and decreased with others (e.g., Combretum collinum, Harungana madagascariensis and Hyparrhenia diplandra). Linear regressions showed that MIP increased significantly with the specific richness of woody species identified as indicators and with the amount of annual herbs. Woody legumes with high root colonization by AMF appeared to be refuge plants, and primary AMF dispersal vectors, increasing soil MIP. This study provides baseline data that can be used to formulate ecological restoration strategies, including soil and vegetation protection.