02732nas a2200301   4500008004100000245010000041210006900141300000900210490000800219520171100227653001801938653003401956653001601990653009502006653001902101653004602120653001302166653001802179653000902197653001902206100001802225700001902243700001802262700001802280700001802298700002002316856009402336       2005                        eng d00aRegional diversity of mycetophilids (Diptera: Sciaroidea) in Scandinavian oak-dominated forests0 aRegional diversity of mycetophilids Diptera Sciaroidea in Scandi  a9-200 v1213 aMycetophilids is a species-rich insect group for which the ecological requirements in temperate forests are poorly understood. This study of mycetophilids was based on trap samples from 15 oak-dominated sites in the boreonemoral zone of southern Sweden. Species richness and composition were analysed in relation to environmental variables at a local and at larger scales (multiple regression), and compared to results from similar studies in spruce-dominated sites in the boreal zone of Norway (PCA and two-sample t tests). Regressions showing a dominance of regional factors over local in-site variables agree with species-richness models assuming that local communities most often are unsaturated. Precipitation (inter-correlated with elevation) was the strongest factor for explaining the variation in species-richness, which is consistent with previous results indicating that mycetophilids are disfavoured by drought. In addition to precipitation, the area of mixed forest with high biodiversity values (woodland key habitats and protected areas) was a positive factor for species-richness, probably because such habitats combine elements of both coniferous and deciduous forests. PCA ordination revealed a clear separation of the species composition between boreal and boreonemoral forests. Species-richness in boreal forest was significantly higher than in boreonemoral forest, indicating a preference for boreal habitats in many of the species. For mycetophilids and other drought-sensitive insects, it is suggested that (partial) cutting in some dense successional oak stands should be avoided, and that some invading spruces should be tolerated. Copyright 2004 Elsevier Ltd. All rights reserved.10aAngiospermae-10aAnimalia-; [26070-] Fagaceae-10aArthropoda-10aBiodiversity-; Biogeography-: Population-Studies; Forestry-; Terrestrial-Ecology: Ecology-10aDicotyledones-10aEnvironmental-Sciences; [75314-] Diptera-10aInsecta-10aInvertebrata-10aPlan10aSpermatophyta-1 aOkland, Bjorn1 aGotmark, Frank1 aNorden, Bjorn1 aFranc, Niklas1 aKurina, Olavi1 aPolevoi, Alexei  uhttp://www.online-keys.net/sciaroidea/2000_/Okland_et_al_2005_regional_Mycetophilidae.pdf