Rehabilitation promotes rapid recovery of arbuscular mycorrhizal fungi in iron mining areas

Abstract

Arbuscular mycorrhizal fungi (AMF) perform important ecological functions in the rehabilitation of degraded areas, acting through several mechanisms, such as the production of glomalin-related soil proteins (glomalin), which act as cementing agents and nutritional reserves and sequester carbon in soil. The aim of the present study was to determine whether a short rehabilitation time influenced the soil AMF community diversity and glomalin production in areas undergoing rehabilitation after iron mining. We analyzed the number of spores, mycorrhizal colonization, AMF species richness, and concentrations of easily extractable and total glomalin-related soil proteins. Species richness was reduced by approximately 50 % after mining activity. However, after the initial rehabilitation of degraded areas, we observed an increase in the number of spores, colonization, and AMF species. Families Glomeraceae and Acaulosporaceae were considered dominant in the studied areas. Glomus sp.1 and Acaulospora mellea were the most frequent morphotypes. The relationship between glomalin and the levels of dissolved organic carbon, total carbon, and total nitrogen in the soil was found to be an interesting and easily interpretable parameter of the influence of AMF on the storage of organic matter in the soil, indicating the degree of equilibrium and/or recovery of revegetated environments. Rehabilitation, even in early stages, favored improvements in AMF status and provided increases in total glomalin-related soil protein production, which may have contributed to the enrichment of carbon and nitrogen in the soil. These characteristics are indicative of the success of the rehabilitation actions carried out in these areas after mining activity.