Reforestation processes, seasonality and soil characteristics influence arbuscular mycorrhizal fungi dynamics in Araucaria angustifolia forest

Intensive logging of Araucaria angustifolia has reduced the extension of Araucaria-dominated forests, causing a strong disturbance on the arbuscular mycorrhizal fungal (AMF) community. AMF play an important role in soil health and Araucaria forest establishment. However, the main drivers that determine the AMF dynamics in native and reforested areas remain poorly understood. Our study aimed at evaluating important factors (i.e. soil and litter characteristics, seasonality and reforestation practices) that can alter AMF community dynamics. We evaluated three regions of Araucaria forest located in Sao Paulo state, Brazil, including native and reforested sites. We evaluated the AMF community through soil spore extraction and identification and root colonization rates, and we compiled the data using correlations and diversity metrics (richness, abundance and diversity). Together, we recorded thirty-six AMF species during the two sampling periods at all sites. Genera with the greatest numbers of species were Gloms, Acaulospora, Scutellospora and Gigaspora. Soil macroporosity, K and P were always higher in native forests and moisture was higher in reforested sites. Root colonization, though also affected by seasonality, showed differential behavior for each region. In addition, AMF species abundance changed between native and reforested sites and according to the season. In region 1, when correlating AMF and physical-chemical soil and litter attributes in a Redundancy Analysis, there were few differences between native and reforested sites, both being very similar. However, native and reforested sites were clearly discriminated in the other two regions, mainly influenced by bulk density, litter N, pH, Al, total porosity and moisture. The main influence in AMF dynamics composition were litter physical and chemical attributes. However, the reforestation process and seasonality, especially in summer, contributed to discriminate regions, indicating the relevance of these aspects on the AMF profile, reinforcing the importance of integrating tools in the evaluation of the biological data set.