Importance of high quality early-successional habitats in managed forest landscapes to rare beetle species

Abstract

Species adapted to early-successional forest habitats are in managed landscapes largely confined to clearcuts. To improve habitat quality on clearcuts, green tree and dead wood retention is widely applied in forestry; however, its effects on rare early-successional species have rarely been shown. We repeatedly surveyed two red-listed beetle species (Upis ceramboides and Platysoma minus) on clearcuts in a managed boreal forest landscape. We found that U. ceramboides decreased its occupancy over time while P. minus increased, indicating that red-listed species vary in their ability to successfully utilise managed habitats. We found no effect of connectivity on probability of occurrence, colonisation or extinction per clearcut. Trees retained alive improved habitat quality of clearcuts, since both species were more frequent in dead wood of such trees, in comparison to logging residues. We suggest that retention can be improved by protecting and creating dead wood as intact trees during harvesting. Rare specialist species require habitat of high quality, and consequently it is impossible to meet the requirements of these species on every clearcut. To preserve all early-successional species at a regional scale, we recommend focusing retention of green trees and dead wood to one or a few trees species on each clearcut and in each landscape.