Résumé
Aims: Determining which abiotic and biotic factors influence soil aggregate stability (MWD) in tropical climates is often confounded by soil type, especially when large amounts of aluminium and iron oxides are present, such as in Ferralsols. We aimed at understanding the role of soil physical and chemical components, vegetation and fungal biomass influencing the aggregate stability of a Ferralsol along a successional gradient of vegetation in New Caledonia.Methods: Five plant communities, ranging from sedge dominated ecosystems to well-established mixed rainforest were studied. For each community, MWD, soil texture, soil organic carbon (SOC), iron and aluminium sesquioxides, root length density (RLD), specific root length (SRL), root mass density (RMD) and fungal biomass were measured.Results:The best prediction of MWD combined abiotic and biotic factors. Along the gradient, Fe increased MWD, while root traits, fungal abundance and SOC modified MWD. From the sedge-dominated community to Arillastrum forest, RMD and SOC increased MWD, while between Nothofagus and mixed rainforest, it was likely that floristic composition and fungal communities influenced MWD.Conclusion : Plant community, the intrinsic nature of Ferralsol and fungal abundance all modified MWD. However, the specific effect of microbial communities should be addressed through a metagenomics approach to elucidate microbial interactions with plant communities.