Impacts of Canopy Disturbances by Tree Logging on Soil Biota Increase With Organism Size.

Soil biota is essential for forest ecosystems' functioning as it plays a key role in litter decomposition, nutrient recycling, and soil carbon sequestration. Since forest disturbances can have major impacts on soil biota and associated ecosystem services, there is an urgent need to provide evidence on its ecological responses to such disturbances. To this end, we established an experimental site to study the impacts of disturbance on soil biota abundance and properties resulting from tree-felling interventions of different intensity as well as from post-disturbance treatments (adding slash or not to the soil) in a Quercus faginea Lam. forest located in northern Spain. The experimental design consisted of a randomized block design that included five treatments: control, 50% canopy disturbance with and without slash, and 100% canopy disturbance with and without slash. Comprehensive inventories of soil biota, including microbes, microfauna, mesofauna, and macrofauna, were carried out after one, nine, and 21 months following the disturbance. Our results showed how body size determined the response of the soil community to canopy disturbance intensity and time since disturbance. Generally, the effects of the disturbance treatments were more severe as the size of the organisms increased and as the disturbance intensity increased. We conclude that while forests may show a certain capacity to absorb disturbances, assisting soils with slash addition after disturbances helps maintain habitats and the soil microclimatic conditions to conserve soil biota and functions. Moreover, organism body size emerges as a potential integrative functional trait indicative of responses to disturbance. Our results, derived from a quite unique multi-taxon study, have important implications not only for biodiversity conservation but also for forest managers and policymakers.