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Management of boreal forests for timber production has caused changes in forest structures and disturbance regimes, which have influenced a wide range of organisms. The aim of this study was to evaluate how composition of epigaeic (ground-living) beetle assemblages is influenced by stand age and management history in a heavily managed boreal forest landscape. We compared the epigaeic assemblages among stands of three ages: (1) young (8–25 years) and (2) middle-aged (40–58 years) stands regrown after clear-cutting, and mature stands (80–130 years) that had been selectively cut historically but never clear felled. We sampled epigaeic beetles in each of 42 stands, using 10 pitfall traps during seven summer weeks. More than 9000 specimens were collected and identified. The assemblages in young stands differed from those in middle-aged and mature stands, both for the Staphylinidae (rove beetles) and all beetle families combined. Carabidae (ground beetles) composition differed between young and middle aged stands only, and assemblages of Curculionidae (weevils, bark beetles and allies) differed between young and mature stands only. Assemblages of Leiodidae (round fungus beetles) had similar composition in all three stand types. Considering all families, young stands generally harbored fewer species and lower abundances compared with middle aged and mature stands. However, the Leiodidae had similar species richness in all three stand types. The lack of differences in assemblage composition, species richness and abundance between middle aged and mature stands suggests that epigaeic beetle assemblages recolonize following clear-felling. However, our collections included large numbers of unique and usually rare species in mature stands, indicating that old forest is important for the conservation of epigaeic beetles. Furthermore, the lower abundance of these beetles in young stands indicates that an increasing proportion of young stands on managed landscapes will reduce the overall abundances of epigaeic beetle species, with potentially negative impacts on recolonization. [ABSTRACT FROM AUTHOR]

Highlights: [•] We review environmental considerations in forestry with Sweden as a case study. [•] Environmental considerations in forestry have support in the scientific literature. [•] Retention levels in Sweden are low compared with ecological thresholds. [•] There is a need to better adjust the levels above thresholds from empirical studies. [•] The allocation of consideration in and among landscapes needs to be improved. [ABSTRACT FROM AUTHOR]

Abstract: Intensive forest management has dramatically reduced the area of old-growth forest in Fennoscandia. We examined if the proportion of old forest in a landscape affects species composition, richness and abundance of saproxylic beetles. We used tube-shaped window traps in five pairs of sites, selected so that the sites within each pair differed with respect to the proportion of old forest (>125years) in the surrounding landscape. A landscape level inventory of the wood fungi Fomitopsis rosea, as a proxy for forest with high conservation values, was used to complement the data on old forests. In addition, to testing whether mycelia-colonised wood may attract saproxylic beetles, the tube-shaped window traps were baited with wood colonised by Fomitopsis pinicola or F. rosea. Old-forest-rich landscapes supported significantly more species and a higher abundance of saproxylic beetles than old-forest-poor landscapes. The analysis revealed a clear connection between the community composition of saproxylic beetles and the proportion of old forest and number of F. rosea fruiting bodies in the surrounding landscape (radius 3km). The local landscape species pool thus appears to be important for the beetle species that are trapped since the composition of saproxylic beetles differed between the two landscape types. The effects of the different baits were less pronounced than the effect of landscape type, although species-specific responses to the two mycelia baits were observed. This indicates that volatiles from mycelia of wood-decaying fungi and the mycelial community may affect colonisation patterns of saproxylic beetles. Our results suggest that forest fragmentation and habitat loss have resulted in depauperate beetle faunas in old-forest-poor landscapes. Our results highlight the need to invoke a landscape scale approach for preserving biodiversity, in this case the need to maintain a sufficient proportion of forest with old growth characteristics in the managed landscape. [Copyright &y& Elsevier]

Abstract: Predatory beetles are important natural enemies of early successional cambium feeding beetles and knowledge about their ecology is of paramount importance for biological control and sustainable forest management. We used a large-scale experiment including 3 stand types (clear-cut, mature managed and old-growth stand) and 6 dead wood substrates (burned, shaded, white rot inoculated, brown rot inoculated, untreated control logs and created snags) to test substrate preferences of 10 common predatory beetle species. We collected insects in eclector traps and measured dead wood availability within 100m from the experimental logs at each site. We also tested the relationships between predators and prey at the trap level. Stand type was important for all predators; Nudobius lentus and Ampedus tristis were more abundant on clear-cuts while Phloeonomus sjoebergi, Quedius plagiatus, Epuraea boreella, Epuraea pygmaea, Epuraea angustula, Rhizophagus dispar and Epuraea laeviscula were more abundant in mature managed and old-growth stands. Snags differed most from the control logs supporting significantly more E. boreella and E. angustula and significantly less P. sjoebergi, E. pygmaea, A. tristis and R. dispar. Prey abundance proved to be more important than dead wood availability at the stand level for most species, although the response varied among species. At the trap level, the abundances of P. sjoebergi, E. laeviscula and Q. plagiatus were correlated with the abundances of their known prey species. P. sjoebergi, E. boreella, E. pygmaea, R. dispar and N. lentus were correlated with total bark beetle abundance suggesting that many predators might be less specific in their choice of prey than previously thought. The variable response of the 10 examined predatory beetles at different levels of scale suggests complex relationships with their prey and environment. The conservation of this group of beetles is important both to achieve environmental goals but also for biological control of potential pest species. Thus, conservation oriented measures needs to be performed aiming at improving both substrate and stand qualities. [Copyright &y& Elsevier]

Abstract: Different functional groups of beetles are likely to exhibit different responses to forest management and it is essential that we gain knowledge on these responses to understand and minimize the negative impacts of forestry in boreal ecosystems. In a large-scale manipulative experiment in nine sites (including 27 stands) in northern Sweden, we tested how saproxylic beetles, fire-favoured beetles and functional groups of beetles were affected by log treatment (shaded, burnt and fungi inoculated logs) and stand type (clear-cuts, mature managed and old-growth stands). All sites included one clear-cut, one mature managed stand and one old-growth stand, which give in total 27 stands. Fresh logs were placed out in the stands and exposed to different treatments. Insects were caught in eclector traps attached to the experimental logs. Log treatment, stand type and their interactions affected abundance, species richness and assemblages of saproxylic beetles, fire-favoured beetles and functional groups of beetles. Cambium consumers were less abundant on burnt logs compared with control logs. Furthermore, the assemblage composition differed between burnt logs and control logs for fire-favoured species and cambium consumers. On the clear-cuts burnt logs hosted lower abundance of all saproxylic beetles and fire-favoured species. For predators, the assemblage composition differed between burnt logs and control logs on clear-cuts. Shaded logs hosted lower abundance of wood borers compared to control logs. Shaded logs also supported different assemblages of saproxylic beetles and predators compared with the control logs on clear cuts. The effect of stand type was stronger than the effect of log treatment and for most of the examined groups; the clear-cuts differed from the mature managed and old-growth stands, while few differences was detected between mature managed and old-growth stands. The results indicate that in an area with intense forestry, both old-growth forest reserves and the creation of suitable substrates in managed forests are needed to conserve functionally intact beetle assemblages. [Copyright &y& Elsevier]

Abstract: Many saproxylic beetles do not feed on wood directly but on fungi colonizing the wood. The volume of decaying wood has decreased drastically in Scandinavian managed forest landscapes in recent years, so improved knowledge on the interactions between beetles and wood-decaying fungi is important for the long-term persistence of these trophic partners. Sporocarps of polypores are known to emit volatiles attracting both fungivorous and predatory beetles, but it is unknown whether some beetles are also attracted to odours from the mycelia. The aim of this experiment was to test the attraction of beetles to volatiles from the sporocarps and mycelia of wood-decaying fungi. In a randomized block design, six substrate types: Fomitopsis pinicola sporocarp, F. pinicola mycelium-infected wood, Fomitopsis rosea sporocarp, F. rosea mycelium-infected wood, Phellinus chrysoloma sporocarp and Phlebia centrifuga mycelium-infected wood were attached separately to specially designed window traps in four old-growth spruce forests in northern Sweden. Empty traps and traps with sterilised wood were used as controls. We found no significant differences in the species richness or abundance of saproxylic beetles between the control and sterilised wood and the fungal substrates. However, two abundant species showed significant preferences for one substrate type. The bark beetle Dryocoetes autographus preferred F. rosea mycelium-infected wood and the rove beetle Lordithon lunulatus preferred fruiting bodies of F. pinicola. The results indicate that some species do discriminate between volatiles emitted by different polypore species and also between volatiles emitted by the sporocarps and mycelia from the same species. Our data indicate a hitherto unknown interdependence between D. autographus and F. rosea. We conclude that present knowledge on interactions between beetles and wood-decaying fungi is limited and further studies are needed to enhance our ability to design appropriate conservation strategies in the forest landscape. [Copyright &y& Elsevier]