The rehabilitation of mine-impacted areas through ecological restoration can ensure long-term ecosystem resilience by reestablishing at least part of the original biodiversity. In New Caledonia, large surfaces of mined land need to be restored. Arbuscular mycorrhizal fungi (AMF) are abundant in New Caledonian serpentine (ultramafic) ecosystems and play important roles in plant development and adaptation to environmental stresses. In a greenhouse experiment using the endemic shrub Metrosideros laurifolia, we compared the functional effects of AMF community extracted from a lateritic subsoil restored 20 years ago with that extracted from a reference soil corresponding to a bordering dense shrubby maquis. In the restored subsoil, deficient in major mineral elements, the two AMF communities did not improve plant growth, unlike in the reference soil, where a strong mycorrhizal growth response was observed. Moreover, in the reference soil, mineral nutrition was more stimulated by the AMF community from the same soil than that from the restored soil, and metal concentrations in plant organs were globally lower in plants inoculated with AMF from the reference soil. In the restored soil, global microbial activity was higher in the presence of the AMF community from the reference soil than in the restored soil. All these results suggest that the AMF community that evolved in the restored substrate was less efficient at promoting plant development than that in the reference soil.