Soil biological activity in veredas under different stages of degradation

Veredas are hydromorphic ecosystems of the Cerrado and important carbon pool. In the semi-arid region of Minas Gerais, climate change and anthropogenic actions have altered carbon dynamics and soil microbial activity in dry and open areas of this environment. This study evaluated soil microbial biomass carbon (Cmic), basal soil respiration (BSR), and the soil metabolic quotient (qCO2) in three environments (hygrophilous forest, open areas, and dry areas) of two veredas, Amescla and Das Pedras, in northern Minas Gerais. In the Amescla vereda, higher Cmic values occurred in the hygrophilous forest (208.01 µg C g⁻¹ soil), differing from open areas (105.07 µg C g⁻¹ soil) and dry areas (125.81 µg C g⁻¹ soil). In the Das Pedras vereda, the hygrophilous forest (205.18 µg C g⁻¹ soil) and open areas (173.60 µg C g⁻¹ soil) showed higher values than dry areas (73.93 µg C g⁻¹ soil). BSR showed no significant differences among environments in both veredas. The soil metabolic quotient (qCO2) did not differ significantly; however, it showed an increasing trend in the drier zones of the Amescla vereda, with values of hygrophilous forest (1.17 µg CO2-C g⁻¹ Cmic h⁻¹), open areas (1.28 µg CO2-C g⁻¹ Cmic h⁻¹), and dry areas (1.79 µg CO2-C g⁻¹ Cmic h⁻¹), indicating metabolic stress. In Das Pedras, qCO2 values were more stable, suggesting greater microbial efficiency. Our findings indicate that hygrophilous forest areas preserve microbial biomass carbon (Cmic); however, they are particularly vulnerable to anthropogenic disturbances under progressive degradation scenarios.