High Diversity of Saproxylic Beetles in a Hemiboreal Mixed Forest Reserve in the south of Norway
Altogether 335 species of saproxylic beetles were collected by Malaise, window and emergence traps in a 33 ha forest reserve in southern Norway, during the years 1992–1997. Most species are associated with deciduous trees, particularly oak, and the majority depend on decayed wood or fungi. The forest is a mixture of Norway spruce and deciduous trees and is characterized as being very close to a primeval forest. Sixty–two species of the collected beetles are assumed to be threatened or rare in Scandinavia, 52 species are on the Red Data List in Sweden and 43 species are suggested for a similar list in Norway. Fifteen species are on a list of species threatened in the Nordic region. Compared with other thoroughly sampled forest reserves in Fennoscandia, the forest investigated had one of the richest saproxylic beetle communities known to date. The main reasons for this are assumed to be the abundance of dead wood, the diverse tree composition and the fact that the area had been inaccessible for forest harvesting due to the lack of transportation for timber.