Comparison of moth communities following clear-cutting and wildfire disturbance in the southern boreal forest

Nocturnal macrolepidopteran fauna (moths) of the southern boreal forest of Ontario, Canada, were compared between forests clear-cut or burned by wildfire approximately 5 years previously to assess whether their assemblages differed following disturbance. Moths were light-trapped for 27 days during the summer in three burned and three clear-cut sites that had been formerly mature mixed jack pine (Pinusbanksiana) forest. The dominant species varied throughout the summer (Protorthodes oviducadominated in June, Orthodes cynica in July and Idia americalis in August), but they were similar between disturbance types. Diversity indices were similar although ordinations showed significant differences between the two disturbance types. Nine species were more significantly abundant in burn than clear-cut sites (Callopistra cordata, Cyclophora pendulinaria, Gluphisia septentrionis, Hyppa nr. xylinoides, Nemoria rubrifrontaria, Semiothisa neptaria, Spiramater lutra, and Tacparia detersata), whereas the converse was true for three species (Acronicta innotata, Phyllodesma Americana, and Euxoa comosa). Vegetation composition, disturbance age, percentage of jack pine pre-disturbance, and amount of downed woody debris and snags were the most important environmental correlates of moth community composition. Our study supports that of previous work on the effects of forest disturbance and biodiversity suggesting that clear-cutting may emulate wildfire for some organisms, but not for others. Thus, forest managers must consider multiple aspects of forest structure in attempting to use clear-cuts to mimic fire

Differences between forest type and vertical strata in the diversity and composition of hymenpteran families and mymarid genera in northeastern temperate forests

Most insects' assemblages differ with forest type and show vertical stratification. We tested for differences in richness, abundance and composition of hymenopteran families and mymarid genera between sugar maple (Acer saccharum) and white pine (Pinus strobus) stands and between canopy and understory in northeastern temperate forests in Canada. We used flight interception traps (modified malaise traps) suspended in the canopy and the understory in a split-split block design, with forest type as the main factor, forest stratum as the first split factor, and collection bottle location as the second split factor. Hymenopteran families and mymarid genera differed in their diversity depending on forest type and stratum. Both family and genera richness were higher in maple than in pine forests, whereas family richness was higher in the canopy and top bottles and generic richness was higher in the understory and bottom bottles. Multivariate analysis separated samples by forest type, vegetation stratum, and bottle location. Family composition showed 77% similarity between forest types and 73% between the canopy and understory. At the lower taxa level, mymarid genera showed only 47% similarity between forest types and 40% between forest strata, indicating vertical stratification and relatively high β-diversity. Our study suggests that hymenopteran diversity and composition is strongly dependent on forest type and structure, making flying members of this order particularly vulnerable to forest management practices. It also shows that insect assemblage composition (especially at low-taxon levels), rather than relative abundance and richness, is the community attribute most sensitive to forest type and vertical stratification. © 2007 Entomological Society of America.Fil:Bellocq, M.I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina