Influence of canopy gaps on saproxylic beetles in primeval beech forests: a case study from the Uholka-Shyrokyi Luh forest, Ukraine

The distribution of canopy gaps has been studied intensively in primeval forest, but their role as keystone structure for biodiversity under natural conditions is still poorly understood. We investigated the effect of habitat properties on saproxylic beetles in the centre, at the edge of gaps and in closed stands in one of the last and largest primeval beech forest of Europe (Uholka‐Shyrokyi Luh forest, Ukraine). The abundance of saproxylic beetles was significantly higher in canopy gaps compared to the closed forest. The number of species did not differ significantly between gap centres and closed forest, but was higher in gap centres than at gap edges. Species composition in gap centres was clearly distinct from that in closed forests. The effects of biotic resources, such as the amount of dead wood or the density of big trees (DBH>70 cm), on diversity measures were weak, which might be caused by the abundance of these resources under natural conditions. Since our study site is embedded in a landscape dominated by primeval forest, the effects of habitat properties on saproxylic beetle fauna might differ from that in managed forests of Central Europe. Nevertheless, species assemblages in primeval beech forests play an important role as a reference for conservation efforts in managed beech forests of Europe.