Higher Population Densities of the Abundant Specialist Gyrophaena boleti in Near Natural than Previously Clear-Cut Mature Forests

Abstract

Boreal forests are home to thousands of species, many of which are dependent on dead wood. In Norway, more than half of the known species live in the forest. Modern forestry in Norway has altered the characteristics of forests, creating homogenous forest stands of even aged trees with low volume and diversity of deadwood, risking the habitat of saproxylic organisms. In this study, I investigated the saproxylic beetle Gyrophaena boleti (L.) in previously clear-cut and near natural forests in South-eastern Norway by window traps and individual counts on the underside of Fomitopsis pinicola (Fr.) Karst. fruit bodies. A higher number of G. boleti was trapped in the near natural forests compared to the previously clear-cut forests. The difference could be explained by a higher volume of deadwood in early decay stages, facilitating for more F. pinicola which is the main habitat for G. boleti. There was no significant difference in the density of G. boleti on the hymenium of F. pinicola between the two forest types. However, as fruit bodies of F. pinicola occurred in higher numbers and were larger sized in the near natural forests, estimated population densities of G. boleti were higher in the near natural forests. This study shows that the abundance of even common forest species such as G. boleti can be reduced as a result of clear-cutting compared to near natural forests.