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Large scale use of even-aged silviculture (clear-cutting) commencing in the mid-20th century has had negative impacts on forest biodiversity. As a consequence, uneven-aged silviculture is currently being considered to help meet the ecological and social criteria required for sustainable forest management. Uneven-aged silviculture (e.g. selective felling) involves selective removal of some older trees in a stand which may to some extent mimics natural small scale stand dynamics and thus potentially benefit species associated with old forests. Here we test whether selective felling benefits beetle biodiversity by producing beetle assemblages that better resemble those of old growth stands than those found in uncut production stands. We conducted a field study in northern Sweden, comparing beetles assemblages collected with window traps in three spruce dominated stand types: (1) Stands recently (on average 7 years prior to the study) subjected to selective felling ( Selective felling ), (2) mature uneven-aged stands without recent history of management, resembling selective felling stands prior to management ( Uncut ), and (3) old-growth stands with high conservation values ( Old growth ). As predicted, we found that assemblage composition was similar in selective felling and old growth stands, and that assemblages of cambivores and obligate saproxylics (marginally significant) differed between these two stand types and uncut stands. The differences were largely explained by a higher abundance of saproxylic species presumably associated with old growth conditions and large volumes of deadwood. Thus, although overall assemblage composition did not differ between stand types, part of the beetle community seemingly benefited from selective felling. We therefore recommend that selective felling is considered as an alternative to clear-felling to maintain biodiversity values. [ABSTRACT FROM AUTHOR]

Topographic heterogeneity causes gradients in altitude, potential solar radiation and soil humidity on a range of scales from micro- to macro-habitat. These gradients are important determinants for the distribution of many organisms but have been largely neglected in studies of species associated with dead wood, a group of great conservation concern. In this study, we evaluated the effects of topography-related gradients (altitude, potential solar radiation and soil humidity) and habitat characteristics (bark cover, ground contact and dead wood volume) on saproxylic (wood-inhabiting) beetle assemblages. We sampled boreal saproxylic beetles hatching from 750 experimentally exposed spruce and birch logs in a regional scale field experiment including 10 landscapes and spanning gradients of altitude (range 85–510 m asl), potential solar radiation (based on slope and slope aspect and highest in equator-facing slopes, PADIR, range 0.24–0.71) and soil humidity (humidity index, range 2.3–3.1). The logs were placed in north Swedish forests and clear-cuts and beetles were sampled with emergence traps the 4th summer after the logs were introduced. Saproxylic assemblage composition varied considerably in response to altitude, potential solar radiation and soil humidity. The response was evident in both forests and clear-cuts and for both birch and spruce logs. Species density and abundance responses differed among trophic groups. For birch logs, fungivore species density increased significantly with increased potential solar radiation. For spruce logs, altitude affected total species density and density of cambium consumers positively and abundance of fungivores negatively, suggesting a delay in succession due to slower decomposition at higher altitudes. In addition to the topography-related gradients, ground contact and bark cover of logs as well as the availability of dead wood in the vicinity influenced the beetle assemblages. Our results clearly show that topography-related gradients affect assemblage composition of saproxylic beetles. These factors should be considered in the management of saproxylic biodiversity. To ensure the safeguarding of intact saproxylic assemblages it is important that the full range of dead wood habitats is conserved. Topographic heterogeneity may provide opportunities for landscape scale survival in response to rapid climate change but there is also a risk that some niches will disappear. Some of the negative effects of climate change could be mitigated by allocating set asides and restoration efforts in areas where gradient in altitude, solar radiation and soil humidity are particularly well developed over short distances. [ABSTRACT FROM AUTHOR]