Are microbial activity and arbuscular mycorrhizal fungal community influenced by regeneration stages? A case study in Southern Brazil coastal Atlantic Rain Forest

Abstract

Aiming to describe coastal Atlantic Rain Forest (ARF) regeneration dynamics, we evaluated attributes linked to soil biota and mycorrhizal symbiosis in two coastal ARF sites in Florianópolis, Southern Brazil. In each site, we selected forest transects in early regeneration (ER) and advanced regeneration (AR) stages, i.e., about 20 and 50 years without agricultural use, respectively. Soil total organic carbon (TOC) was higher in AR than in ER stage. Soil microbial biomass carbon (MBC) varied between sites and was higher in the AR than in the ER stage. Basal respiration and qCO2 rates differed between sites and were, respectively, higher and lower in advanced regeneration stage areas. Arbuscular mycorrhizal (AM) root colonization and AM fungal spore density were higher in the ER stage, with no difference between sites. Principal Component Analysis (PCA) for correlation between soil microbiological and chemical attributes showed that the variables with the most influence on sample separation for the first component were total spore number, soil MBC, root mycorrhizal colonization, and soil TOC. Soil pH, available P, and qCO2 had the highest influence on the second component. This analysis separated samples by regeneration stage, and sites differed only in AR stage. PCR-DGGE analysis on DNA extracted from soil samples showed that AMF community structure differed more between sites than between regeneration stages.