Effects of forest management and microbial diversity and community composition on soil respiration

Soil microbes are responsible for important ecosystem services such as nutrient cycling and decomposition, and as such their activity is an important contributor to GHG emissions from soils. However, while microbial biomass is known to affect soil C turnover, the role of community composition and diversity is less clear. It has been theorized that microbial functional diversity may be a useful predictor of decomposition rates, but empirical data from natural systems are ambiguous. In addition, the contribution of diversity to decomposition may be affected by the different sensitivity of various fungal and bacterial functional groups to land management. In this study we aim to disentangle the direct effect of forest management on decomposition rates via changes in soil moisture and temperature, from its indirect effects via changes in microbial community composition. We use empirical data collected from multiple forest management experiments across Europe by the HoliSoils consortium (Holistic management practices, modelling and monitoring for European forest soils; https://holisoils.eu/). Preliminary results indicate a significant correlation between microbial diversity and soil respiration, but with significant differences between fungi and bacteria. This suggests that identifying appropriate diversity indicators could improve microbially explicit C turnover models and inform forest management practices for climate impact mitigation.