TY - JOUR

T1 - Numerical responses of saproxylic beetles to rapid increases in dead wood availability following geometrid moth outbreaks in sub-arctic mountain birch forest

AU - Vindstad, Ole Petter Laksforsmo

AU - Schultze, Sabrina

AU - Jepsen, Jane Uhd

AU - Biuw, Martin

AU - Kapari, Lauri

AU - Sverdrup-Thygeson, Anne

AU - Ims, Rolf Anker

PY - 2014/6/9

Y1 - 2014/6/9

N2 - 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.

AB - 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.

KW - Biology

KW - 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 abunda

KW - Atheta taxiceroides

KW - betula pubescens

KW - Ecosystems Research

KW - beetle;

UR - http://www.scopus.com/inward/record.url?scp=84902602814&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/4ccd20d4-0f92-3b3a-b5e1-6adf4d884b12/

U2 - 10.1371/journal.pone.0099624

DO - 10.1371/journal.pone.0099624

M3 - Journal articles

C2 - 24911056

AN - SCOPUS:84902602814

VL - 9

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 6

M1 - e99624

ER -