Numerical responses of saproxylic beetles to rapid increases in dead wood availability following geometrid moth outbreaks in sub-arctic mountain birch forest

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Authors

  • Ole Petter Laksforsmo Vindstad
  • Sabrina Schultze
  • Jane Uhd Jepsen
  • Martin Biuw
  • Lauri Kapari
  • Anne Sverdrup-Thygeson
  • Rolf Anker Ims

Saproxylic insects play an important part in decomposing dead wood in healthy forest ecosystems, but little is known about their role in the aftermath of large-scale forest mortality caused by pest insect outbreaks. We used window traps to study short-term changes in the abundance and community structure of saproxylic beetles following extensive mortality of mountain birch in sub-arctic northern Norway caused by an outbreak of geometrid moths. Three to five years after the outbreak, the proportion of obligate saproxylic individuals in the beetle community was roughly 10% higher in forest damaged by the outbreak than in undamaged forest. This was mainly due to two early-successional saproxylic beetle species. Facultative saproxylic beetles showed no consistent differences between damaged and undamaged forest. These findings would suggest a weak numerical response of the saproxylic beetle community to the dead wood left by the outbreak. We suggest that species-specific preferences for certain wood decay stages may limit the number of saproxylic species that respond numerically to an outbreak at a particular time, and that increases in responding species may be constrained by limitations to the amount of dead wood that can be exploited within a given timeframe (i.e. satiation effects). Low diversity of beetle species or slow development of larvae in our cold sub-arctic study region may also limit numerical responses. Our study suggests that saproxylic beetles, owing to weak numerical responses, may so far have played a minor role in decomposing the vast quantities of dead wood left by the moth outbreak.

Original languageEnglish
Article numbere99624
JournalPLoS ONE
Volume9
Issue number6
Number of pages13
ISSN1932-6203
DOIs
Publication statusPublished - 09.06.2014

    Research areas

  • Biology - birch; community structure; dead wood; Denticollis borealis; Enicmus lundbladi; epidemic; Epirrita autumnata; forest; larval development; litter decomposition; mortality; moth; nonhuman; Norway; Operophtera brumata; organisms by habitat; population abundance; saproxylic species; species difference; species diversity; wood; animal; Arctic; ecosystem; forest; geography; moth; population density, Atheta taxiceroides, betula pubescens
  • Ecosystems Research - beetle;

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