Soil Microbial Biomass as an Edge Effect Indicator in Semi-Deciduous Seasonal Forest Fragments

ABSTRACT This work had the objective to evaluate the activity and microbial biomass of the soil as an indicator of edge effect in Semi-Deciduous Seasonal Forest fragments. Three fragments of different sizes (small, medium and large) located in the Southwest region of Bahia state were evaluated, in which three sampling ranges were defined in each, and soil samples were collected. The carbon and nitrogen contents of the microbial biomass were determined by the fumigation-extraction method and soil respiration. The microbial biomass carbon (MBC), metabolic carbon quotient (qCO2) and the microbial C:N and MBC:C ratios were discriminating indicators of the edge effect on the soil quality of the studied forest fragments. The integrated analysis of soil microbiological attributes is adequate to evaluate the edge effect in forest fragments. The size of the fragments and their isolation influence the MBC contents, showing greater vulnerability of the smaller fragments in relation to the actions of the external environment.