Influence of clear-cutting, strip-cutting, and logging to construct strip roads on necrophagous silphid and dung beetle assemblages in a conifer plantation

Abstract

ABSTRACT To mitigate the impact of clear-cutting, strip-cutting has been prescribed in Japan. When harvesting trees, logging to construct strip roads is often conducted in adjacent forests. To evaluate the impacts of these logging practices, we collected necrophagous silphid and dung beetles in conifer plantation stands that were connected and partly harvested by strip-cuttings and clear-cuttings, with the construction of strip roads a few months before trapping. The abundances of two of the five species abundant in the uncut forests and the total beetle biomass (dry weight) were higher at the centers of 40-m-wide strip-cuts than near edges and/or at the centers of clear-cuts (≥ 60-m-wide). The beetle assemblages differed between the uncut forests and the uncut strips (unharvested areas of strip-cuttings). However, the abundances of four species abundant in the uncut forests and the biomass were higher in the uncut strips than the strip-cuts. Therefore, we concluded that strip-cutting is a better harvesting method than clear-cutting because strip-cutting mitigated the impact on the beetle assemblages in forests and the ecosystem service estimated from biomass, and the uncut strips retained the beetle assemblages and ecosystem services observed in the uncut forests. The abundances of four species abundant in the uncut forests and the biomass were lower beside the ~2.5-m-wide strip roads than in the uncut forests but were higher than in the strip-cuts, indicating that logging to construct strip roads negatively affected to the forest species and the services, but the negative effect was lower than that of 40-m-wide logging.