Fire and green-tree retention in conservation of red-listed and rare deadwood-dependent beetles in Finnish boreal forests

Published source details Hyvärinen E., Kouki J. & Martikainen P. (2006) Fire and green-tree retention in conservation of red-listed and rare deadwood-dependent beetles in Finnish boreal forests. Conservation Biology, 20, 1711-1719.
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Summary

Habitat loss, fragmentation and habitat degradation have led to declines in biodivesity which might be partly reversed by improving the habitat quality in adjacent areas outside reserves. This study described here looked at 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.

Study area: The study was undertaken in Lieksa and Ilomantsi in eastern Finland (approx. 63ºN, 30ºE) at 24 sites on the southern edge of the middle boreal vegetation zone within a 20 × 30 km block of state-owned land. This comprised mostly managed forests, fragmented by clearcut areas, mires, forest roads, streams and small lakes.

Experimental design and beetle sampling: The sites were dominated by Scots pine Pinus sylvestris and had three levels of green-tree retention (0, 10, and 50 m³/ha) and uncut controls. Twelve of the 24 sites were burned in 2001. The treatments were assigned to the sites randomly, except for the uncut sites, which were situated within the Patvinsuo National Park. Beetles were sampled with 10 flight-intercept traps on each site during the years 2000–2002 (i.e. 1 pretreatment and 2 post-treatment years).

A total of 153,449 individual beetles of 1,160 species were collected in the traps. Of these, 2,107 individuals represented 84 red-listed or rare saproxylic species (in a Finnish context). The richness of these saproxylic 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.

The results show that habitat conditions of many red-listed and rare saproxylic species in this region could be improved significantly with fairly simple alterations to current 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 is also beneficial.

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http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.2006.00511.x