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Habitat loss, fragmentation, and declining habitat quality have created an extinction debt in boreal forests, which could be partly reversed by deliberately improving the habitat quality in managed areas outside reserves. We studied the effects of green-tree retention and controlled burning on red-listed and rare, deadwood-dependent (saproxylic) beetles in a large-scale field experiment in eastern Finland. Our factorial study design included 24 sites dominated by Scots pine (Pinus sylvestris L.) and with three levels of green-tree retention (0, 10, and 50 m3/ha) and uncut controls. Twelve of the 24 sites were burned in 2001. We sampled beetles with 10 flight-intercept traps on each site during the years 2000-2002 (i.e., 1 pretreatment and 2 post-treatment years). A total sample of 153,449 individuals representing 1,160 beetle species yielded 2,107 specimens of 84 red-listed or rare saproxylic species. The richness of these species was higher on the burned than on the unburned sites, and higher levels of green-tree retention promoted species richness, but there were clear differences between the years. The richness of red-listed and rare saproxylic species increased in the first post-treatment year, evidently due to the treatments, continued to increase on the burned sites in the second post-treatment year, but decreased on the unburned sites. Our results showed that the living conditions of many red-listed and rare saproxylic species could be improved significantly with rather simple alterations to forest management methods. Controlled burning with high levels of green-tree retention creates resources for many saproxylic species, but increasing the levels of green-tree retention in unburned areas can also be beneficial.

Aim  Restoration of habitats may be used as a conservation tool when ecosystems have lost their natural structure, dynamics or functioning over large areas. Controlled and planned use of fire could be an effective way to restore habitats of many threatened species in boreal forests where fire suppression has been effective. We asked whether the large‐scale landscape context affects the occurrence of rare and threatened species in forest habitats that have been burned to restore their fire‐related structures. Location  Boreal forests in southern Finland. Methods  We designed a large‐scale field experiment that included nine Pinus sylvestris forests (5–10 ha each) in southern Finland. Sites were located in two regions: (1) in eastern region with shorter management history and (2) in western region where intensive forestry has continued longer. We evaluated whether restoration of dead/burned wood is beneficial for rare and conservation‐dependent species and measured the recovery of pyrophilous and red‐listed insects (beetles and flatbugs) in burned forests, using standardized sampling effort. Altogether, 956 individuals of 29 red‐listed and pyrophilous species were sampled. Results  Rare species colonized areas quickly, but there was a clear difference in species richness between the regions. The eastern forests harboured higher species richness after restoration. In these sites, the average species richness was 13.7 species per site, whereas in western forests it was 5.0 species per site. Similar pattern was also observed in subgroups: the corresponding numbers for pyrophilous species were 9.7 vs. 3.8, for red‐listed 8.7 vs. 2.3 and for red‐listed pyrophiles 4.7 vs. 1.2. Main conclusions  Introducing fire back to boreal forests can aid in the recovery of rare species, but the landscape context considerably affects the success of restoring species. If restored habitats are located in landscapes that have lost their natural properties long ago, the success of restoration seems to be more challenging than in landscapes where habitats have been modified more recently.

Abstract. Sampling of insect communities is very challenging and for reliable interpretation of results the effects of different sampling protocols and data processing on the results need to be fully understood. We compared three different commonly used methods for sampling forest beetles, freely hanging flight-intercept (window) traps (FWT), flight-intercept traps attached to trunks (TWT) and pitfall traps placed in the ground (PFT), in Scots pine dominated boreal forests in eastern Finland. Using altogether 960 traps, forming 576 sub-samples, at 24 study sites, 59760 beetles belonging to 814 species were collected over a period of a month. All of the material was identified to species, with the exception of a few species pairs, to obtain representative data for analyses. Four partly overlapping groups were used in the analyses: (1) all, (2) saproxylic, (3) rare and (4) red-listed species. In terms of the number of species collected TWTs were the most effective for all species groups and the rarer species the species group composed of (groups 1-2-3-4) the larger were the differences between the trap types. In particular, the TWTs caught most red-listed species. However, when sample sizes were standardized FWTs and TWTs caught similar number of species of all species groups. PFTs caught fewer species of all species groups, whether the sample sizes were standardized or not. In boreal forests they seem to be unsuitable for sampling saproxylic, rare and red-listed species. However, the PFTs clearly sampled different parts of species assemblages than the window traps and can be considered as a supplementary method. The abundance distribution of saproxylic species was truncated lognormal in TWT and pooled material, whereas unclassified material failed to reveal lognormal distribution in all the trap types and pooled material. The results show that even in boreal forests sample sizes of at least thousands, preferably tens of thousands of individuals, collected by a high number of traps are needed for community level studies. Relevant ecological classification of material is also very important for reliable comparisons. Differences in the performance of trap types should be considered when designing a study, and in particular when evaluating the results.