The impact of forest management on soil microbial community functions in two forests of South Apennines (Italy)

Forest soils store large amounts of organic matter from aboveground litter. Consequently, practices that affect plant development and soil properties may have crucial impacts on forest ecosystem functions and C feedbacks. In Europe, thinning of forests is a commonly used management practice to promote natural trees regeneration through increasing the temperatures, microbial activity, nutrient availability and irradiance of soil. Forest management influences the occurrence of tree species, the maximum stand density, the organic matter input to the soil decomposer system and hence the availability and quality of microbial resources. Thus, forest management can alter soil microbial community and key ecosystem functions they perform affecting the related ecosystem services, although the functional redundancy of soil microbial communities may minimize these impacts.
Due to the importance of forest soils as both sink and potential source of carbon and their predicted sensitivity to climate change, they became in the last years, one of the key targets of microbial ecologists.
In the present study, we assess the effects of forest management (coppice and high forest) on soil properties and microbial community functions in two Italian forests (turkey oak and beech), in two different seasons, summer and autumn. We investigated functional diversity of microbial communities based on the carbon consumption patterns (by community-level physiological profile, CLPP, and derived average well color development AWCD) and several enzyme activities linked to biogeochemical cycles of C, N and P.
The soil microbial community showed higher metabolic activity in both beech and turkey oak under coppice management (1.32 and 1.54 AWCD, respectively) respect to high forest regime (1.09 and 1.32 AWCD, respectively), only in summer. Significant differences in AWCD values between seasons were found only in forests under high forest management.
Among the investigated soil enzyme activities, only hydrolase showed in summer higher value in beech under coppice respect to high forest management (0.41 vs 0.25 mg FDA g^-1soil d.w. h^-1). This enzyme activity, however, showed higher values in summer than autumn in both forest soils, regardless the management. Hydrolase activity measures the total microbial activity in soil and is a good general index of organic matter turnover in natural ecosystems.
The results will provide useful data for: improving the sustainability of ecosystems in a scenario of climate change; identifying new biological indicators of soil health and fertility to predict the effects of forest practices.