Canadian Forest Service Publications
Lepidoptera from the boreal mixedwood forest in east-central Alberta: comparison of assemblages from a mature stand and an old stand. 2004. Pohl, G.R.; Langor, D.W.; Landry, J.-F.; Spence, J.R. Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta. Information Report NOR-X-396. 20 p.
Issued by: Northern Forestry Centre
Catalog ID: 25002
The Lepidoptera specimens collected in light traps in two Populus-dominated stands in central Alberta, one mature (52 years old) and the other old (>120 years old), were compared. This represents the first detailed examination of these communities, and thus it adds considerable new information on the distribution of arthropods in the boreal forest. In total, 393 species were collected, from an overall regional forest assemblage estimated to contain 481 species. Comparisons of abundance, richness, and diversity were complicated by large year-to-year differences. The indicator value of each common species was assessed; 19 species were deemed to be mature-stand associates and 28 species were deemed to be old-stand associates. More of the old-stand associates were monophagous than was the case for the mature-stand associates. More species unique to a stand were captured in the old stand than in the mature stand. The more specialized community in the old stand is thought to reflect the higher structural complexity of that stand. Many mature-stand and old-stand associates fed on plants that were abundant in both stands, which suggests that they were not limited by host-plant availability. Common species were tested for evenness of distribution across sites, according to a formula developed and presented here; by this measure, 38 species were deemed to be stand generalists. The stand generalists included a greater proportion of polyphagous species than the mature-stand and old-stand specialists. On the basis of the evidence presented here, the macrolepidoptera show promise for use as biodiversity indicators. The Geometroidea and Drepanoidea in particular include many species with strong indicator value for old-growth specialization.