How to promote saproxylic communities in mountain coniferous forests of Switzerland?

Hauser, Gilles (University of Bern and Bern University of Applied Sciences)

Besides being of major importance for wood production, protection against natural hazards or leisure activities, forests are essential in supporting biodiversity. Yet, many of the forest species and especially deadwood associated ones (saproxylic) are threatened because of forest management. To mitigate these threats, different conservation measures are taken, such as the implementation of natural forests reserves excluding wood harvesting. Nonetheless, the effectiveness of this measure in preserving saproxylic communities remains poorly known in Switzerland. In the frame of a national monitoring in natural forest reserves, I investigated saproxylic beetles and fungi in four Swiss coniferous forests, following a pairwise comparison design between managed forests and natural forest reserves. Using a structural equation design, I confirmed the effectiveness of the forest reserve status in boosting species richness of both saproxylic beetles and fungi. This positive effect was identified as being facilitated by tree related micro- habitats. These results give new insights to forest managers willing to conserve effectively saproxylic biodiversity, both by increasing the density of tree related microhabitats, as well as setting aside forest reserves in coniferous forests.