Responses of Syrphids, Elaterids and Bees to Single-tree Selection Harvesting in Algonquin Provincial Park, Ontario (original) (raw)
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Insect communities respond to microhabitat changes caused by forest management. Therefore, it could be used to examine ecological changes following management. Differences in abundance, richness and composition of different insect assemblages at two different taxon levels (Order and family) were assessed. This was undergone at Haliburton Forest, Ontario, Canada dominated by maple-beech trees by setting water-pan traps at five sites. One of the sites has never been harvested while the others have been harvested at different times through the last two decades. Sampling also included locations (edge and center of each harvested site). There were 2270 insects caught in traps, out of them 1206 hymenopteran dominated by Diapriidae. Order Diptera represented by 625 individuals and Muscidae was the most abundant family. Both orders Coleoptera and Hemiptera represented by 241 and 127 individuals. Different cutting dates showed no influence on the structure of selected insect assemblages at the high-taxa level, while few hymenopteran and dipteran families showed some significant change along the time following cutting represented by Diapriidae, Platygastridae and dipteran Muscidae. Regarding locations, there were no significant differences in abundance of different taxa levels. Jaccard index indicated relative similarity in hymenopteran family composition in the study sites and a high similarity (98%) among the two locations. Non-metric Multidimensional Scaling (NMDS) that used to perform ordinations has shown some evidence of segregation of hymenopteran families by site and location. The present study has shown that harvesting of forest tree has a little influence on the changes in associated insect community composition.
Journal of Applied Entomology
The ecology and management of boreal forest ecosystems are drawing greater attention worldwide as their importance is being increasingly recognized for carbon sequestration or for harbouring the world's largest remaining intact forests. Selection cuts have been introduced as a more socially acceptable silvicultural method to improve the maintenance of habitat structure and functions as they mimic aspects of boreal forest succession dynamics. Many studies have shown that selection cutting helps maintaining arthropod communities in mature forests, but few have examined the increased risks of damage by bark- and wood-boring insects in boreal forests of eastern North America. We used multidirectional flight-interception traps to quantify the response of these beetles to 25 and 40% selection cutting in a balsam fir–white birch forest of Québec, Canada. The abundance and species number of both cerambycid and scolytid beetles were 5–6 times larger in selectively cut stands than in cont...
Variable retention harvesting (VRH), in which trees are removed at variable intensity and spatial conÞguration across the landscape, retains greater forest structural heterogeneity than traditional clear-cut harvesting and is being recommended as an alternative for sustainable management of the boreal forest. Little is known about its effects on forest fauna; thus, we studied the inßuence of one type of VRH (harvesting with advanced regeneration [HARP]) on the Syrphidae (Diptera) community in northern Ontario forests of peatland black spruce (Picea mariana). We examined the effects of varying structural retention (from unharvested through partial retention to clear-cut) on syrphid species richness and abundance, and abundance of functional assemblages. Greater species richness and population abundances were found generally in harvested than in unharvested forests. Overall species richness and the abundance of four species (Platycheirus rosarum, Toxomerus marginatus, Xylota annulifera, and X. tuberculata) and larval predators were all higher in both clear-cut sites and those with structural retention than in unharvested sites. Similarly, overall species richness and the abundance of nine species were higher in clear-cut than in unharvested sites. Species responses are discussed in an ecological context. Differences among the levels of forest retention harvesting were relatively minor compared with those of the clear-cut and unharvested area, suggesting that local habitat characteristics may play a more important role in determining the syrphid community than the landscape conÞguration. However, a landscape level effect was evident, suggesting that syrphids may be useful in reßecting changes in stand structure at the landscape scale.
Potential impacts of insect-induced harvests in the mixed forests of New England
Forest insects and pathogens (FIPs) have significant impacts on U.S. forests, each year affecting an area nearly three times the area of wildfires and timber harvesting combined. We surveyed family forest owners (FFOs) in the northeastern U.S. and 84% of respondents indicated they would harvest in at least one of the presented FIP infestation scenarios. This harvest response represents a potentially significant shift in the timing, extent, and species selection of harvesting in the Northeast. Here we used the landowner survey, regional forest inventory data, and characteristics of the emerald ash borer (EAB, Agrilus planipennis) invasion to examine the potential for a rapidly spreading FIP to alter harvest regimes and affect regional forest conditions. Twenty-five percent of the FFO parcels in the Connecticut River Watershed in New England are likely to be harvested in response to EAB within 10 years. This prediction represents an increase in harvest frequencies, from 2.9%/yr (histo...