Assessment of soil microbial functional diversity in a coppiced forest system

Among the bioindicators used to determine soil quality a vast interest is devoted to those related to soil biodiversity; in fact, the ability of a system to withstand stress and abiotic and biotic disturbances depends on its level of biodiversity which is the basis of the functionality of ecosystems. Functional diversity is widely used to gain insight into microbial performances, particularly in presence of a factor of disturbance. In this study we present the changes of microbial functional diversity and other soil chemical and biochemical properties following forest coppicing. The study was conducted in central Italy, in a natural reservation under Quercus cerris spp. plant cover; soils were sampled after three years from coppicing and in an aged coppice taken as control. Trees cutting provoked a decrease of soil total organic carbon (TOC) and a pH increase suggesting a priming effect on native organic matter and qualitative changes in soil solution composition. Microbial indicators (microbial biomass carbon, MBC), basal and cumulative respiration, and indexes (microbial and metabolic quotients) were significantly affected by forest management. Enzyme activities and microbial catabolic activity measured by means of community level physiological profile (CLPP) techniques (MicroResp and Biolog) increased in coppiced plots indicating higher decomposition processes promoted by plant debris and rhizodepositions released after cutting.The calculation of the diversity indexes using both techniques (enzyme activities and CLPP) suggested interesting speculations and perspectives on possible interpretations of these results.

► Forest coppicing modifies soil chemical, biochemical and microbiological properties.
► Microbial biomass and its activities were increased by trees cutting.
► Functional diversity measured with enzymes and CLPP was affected by management.
► Enzymes and CLPP may target different components of microbial functional diversity.