Land-use legacy and tree age in continuous woodlands: weak effects on overall ground beetle assemblages, but strong effects on two threatened species

In woodlands, land use legacy, but also present habitat management can influence biodiversity and ecosystem functions in various ways. However, little is known about how former and current land use interact in woodlands with different habitat continuity and tree age. The aim of this study was to investigate the impact of both habitat continuity and tree age on ground beetles. We performed a field study in the nature reserve Luneburger Heide (Germany). The study area comprised ancient woodland embedded in a matrix of recent woodland. We defined four woodland types by combining ancient and recent woodland with young and old trees and analysed five replicate plots within each of the resulting four woodland types. Habitat continuity, tree age as well as the combination of both of these factors had no significant impact on ground beetle species diversity, abundance, biomass, and evenness with most woodland species occurring on near to all of the four types of woodland plots. Four species, however, showed a significant preference for one of the specified woodland types studied. Our findings provide evidence that all woodland-inhabiting ground beetles of this region are able to colonize new habitats in the continuous woodland matrix, at least, up until a distance of 2.3 km. We call for a heterogeneous woodland management and increasing habitat connectivity to protect both species with a preference for ancient woodland sites and/or old trees and those species which prefer early successional stages.