The influence of variable retention harvesting on forest structure, family-level insect abundance, and hover fly (Diptera: Syrphidae) communities in boreal peatland black spruce forest of north-eastern Ontario

This study analyzes the effect of variable retention harvesting on forest structure and its influence on the aerial insect communities of peatland black spruce forests in north-eastern Ontario. Insects were collected from 24 forest areas that represented a gradient of forest removal from little to no retention of forest basal area in clear-cuts to variable amounts of retention (20%, 27% and 42% basal area) in forest areas harvested with advanced regeneration protection (HARP) to unharvested forest areas. The abundance of Mycetophilidae and several parasitoid taxa including Diapriidae were ameliorated by retention of forest structure. Twenty-seven of 30 insect families and 27 of 28 common (found in 12 or more sites) hover fly (Syrphidae) species (105 in all) had a greatest mean abundance in a HARP treatment. Results suggest the influence of edge area created by HARP is important to the magnitude of species and insect families in peatland communities.