Seven years of follow-up of continuous-cover forestry: responses of saproxylic beetles

Abstract

Fennoscandian forest management has since 1950s been characterized by forest regeneration through clear cutting, with subsequent top-soil preparation, seeding or planting with conifers, and removals of legacy elements important for biodiversity, such as dead wood. According to national Red Lists, this structural simplification in most Fennoscandian forests has made hundreds of species threatened. One possible way to support these species is continuous-cover forestry, where at least half of a stand is covered by mature or near-mature trees throughout the logging rotation. Such forestry might secure both economic benefits and support specialized forest species, but empirical evidence is largely lacking. Therefore, we collected beetles in Eastern Finnish Scots pine forests that represent a continuum from clear-cuts to different continuous-cover forestry techniques, combined with large-sized dead-wood increment, and unharvested mature forest ("control"). We used flight-intercept window traps one year before (2010) and seven years after logging (2011-17) to collect beetle data. We will present comparisons of the overall community, and specialized groups of saproxylic beetles, and associate these patterns with structural features of forest stands, particularly volume and diversity of live and dead trees and size of cleared gaps. Our results will shed light on relative merits of continuous-cover forestry and legacy elements from an ecological point of view. Such information is crucial not only for conservation of biodiversity in managed forests but also for guidelines of forestry.