Silvicultural management does not affect biotic communities in conifer plantations in the short-term: A multi-taxon assessment using a BACI approach

Biodiversity maintenance is a key strategy for sustainable forestry in both above-ground and below-ground biotic communities. However, few studies applied continuous monitoring to analyse the responses of different taxonomic groups to silvicultural treatments. We studied the short-term effects of three silvicultural treatments (no thinning, thinning from below, and selective thinning) on taxonomic richness and composition in two Pinus nigra J.F. Arnold plantations in Tuscany (Italy). We conducted a 1 year before-3 years after control-impact (BACI) experiment with a complete randomized design and analysed the responses of five different taxonomic groups (bacteria, nematodes, microarthropods, mushrooms and vascular plants (overstorey and understorey), along with the patterns of different structural variables. The silvicultural treatments induced a sudden decrease of many parameters such as number of trees per hectare, basal area, and standing volume, with a direct impact on the Photosynthetic Active Radiation on the ground. Despite this, biological communities showed a high resistance to the tree thinning intensities. Indeed, none of the thinning treatments significantly affected the different communities in the short-term, neither regarding taxonomic richness nor composition. The different taxonomic groups showed a similar, low or null, sensitivity to forest management, and thus a high congruence in their responses.