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Habitat requirements of saproxylic beetles on aspen

implications for preservation

Sahlin, Erik (2009). Habitat requirements of saproxylic beetles on aspen. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2009:48
ISBN 978-91-86195-95-3
[Doctoral thesis]

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Abstract

In Fennoscandia, most of the forests have been under production management since the 19th or 20th century, which has resulted in decreasing amounts of dead wood (coarse woody debris, cwd). Populations of many saproxylic (wood–dependent)species have declined because of the reduction of cwd. Forestry is currently trying to increase cwd amounts on clearcuts by green–tree retention. As a result of increased mortality of retained trees this can be expected to enhance cwd amounts on clearcuts. This thesis evaluates whether this practice increases diversity of saproxylic beetles inhabiting aspen. One study compares the habitat availability of aspen–associated beetles (beetles preferring aspen cwd over cwd from other tree species) in clearcuts and forests. A second study focuses on how occupancy (proportion of occupied habitat patches) and density of aspen–associated beetles is influenced by habitat patch size and habitat connectivity. A third study evaluates the contribution aspen cwd on clearcuts makes to total beetle diversity. The results demonstrate that retention of living aspen at clearcutting favours aspen–associated species. Increased tree mortality of retained trees generates more cwd on clearcuts compared with in forests. Thus, a significant part of the beetle populations can be expected to occur on clearcuts. The spatial distribution of the cwd influenced beetle occurrence. Both occupancy and density of aspen–associated beetles was generally higher in larger than in smaller habitat patches. Thus, priority should be given to retain large patches of living and dead aspen. A majority (93 %) of the saproxylic beetle species recorded from aspen cwd in this study was not aspen–associated, i.e. they prefer other tree species than aspen. Also when considering all of these species, clearcuts provide a valuable contribution for maintaining the biodiversity in managed forest landscapes. Species richness was as high in clearcut as in forest sites. In addition, species composition differed between the two stand types which mean that they to some extent are complimentary. The thesis also includes two methodological studies. In one study the efficiency of three different beetle sampling methods (bark sieving, emergence trapping and window trapping) were compared. In another study the aim was to find an efficient odour bait for sampling of flying saproxylic aspen–associated beetles.

Authors/Creators:Sahlin, Erik
Title:Habitat requirements of saproxylic beetles on aspen
Subtitle:implications for preservation
Year of publishing :2009
Volume:2009:48
Number of Pages:48
Papers/manuscripts:
NumberReferences
ALLI. Lars–Ove Wikars, Erik Sahlin, Thomas Ranius (2005). A comparison of three methods to estimate species richness of saproxylic beetles (Coleoptera) in logs and high stumps of Norway spruce. Canadian Entomologist 137(3), 304–324. II. Erik Sahlin, Thomas Ranius (2009). Habitat availability in forests and clearcuts for saproxylic beetles associated with aspen. Biodiversity and Conservation 18(3), 621–638. III. Erik Sahlin, Leif Martin Schroeder. Importance of habitat patch size for occupancy and density of aspen–associated saproxylic beetles (submitted manuscript). IV. Erik Sahlin, Leif Martin Schroeder. Importance of stand type for saproxylic beetles on aspen – a comparison between clearcuts and forest stands (manuscript).
Place of Publication:Uppsala
ISBN for printed version:978-91-86195-95-3
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P01 Nature conservation and land resources
L Animal production > L20 Animal ecology
Subjects:Not in use, please see Agris categories
Agrovoc terms:coleoptera, habitats, boreal forests, populus tremula, deadwood, nature conservation, clear felling, surveys, methods, sweden
Keywords:cwd, aspen, beetles, coleoptera, conservation, methods, habitat availability, patch size, exposure
URN:NBN:urn:nbn:se:slu:epsilon-2947
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-2947
ID Code:2068
Department:(NL, NJ) > Dept. of Ecology
(S) > Dept. of Ecology
Deposited By: Erik Sahlin
Deposited On:19 Aug 2009 00:00
Metadata Last Modified:02 Dec 2014 10:16

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