Saproxylic beetles in managed and seminatural Scots pine forests: quality of dead wood matters

Abstract

Habitats of saproxylic species (species that are dependent on decaying wood) have been greatly changed during the last few decades. Due to intensive forest management, volume of dead wood has decreased and its quality is less diverse in managed than in naturally disturbed forests. There is an urgent need to develop and apply guidelines for forest management so that they also facilitate the survival of saproxylic species and mimic the natural dynamics of forests. This requires detailed information about how the differences in forest structure between managed and natural forests affect the occurrence of species and what are the real habitat requirements of species. Thus, we explored the richness of saproxylic beetles, composition of species assemblages and relationship between saproxylic beetles and their substrate in managed and seminatural pine dominated forests. Richness of saproxylic species tended to be higher in seminatural than in managed forests but the difference was not statistically significant. However, species assemblages in managed forests had differentiated from those on seminatural sites. Our results suggest that for the survival of saproxylic beetles, increasing the total volume of dead wood is an important task but more important one is to improve the diversity and continuity of dead wood in managed forests. This requires that the continuous production of dead wood is allowed also in managed forests to improve the continuity of dead wood and availability of recently dead wood. In green tree retention the main stress should be laid on the trees of large diameter to maintain the potential for large decaying wood.