Spatial and temporal variation of epigaeic beetle assemblages (Coleoptera, Carabidae, Staphylinidae) in aspen-dominated mixedwood forests across north-central Alberta.

Epigaeic beetle assemblages were surveyed using continuous pitfall trapping during the summers of 1992 and 1993 in six widely geographically distributed locations in Alberta's aspen-mixedwood forests prior to initial forest harvest. Species composition and turnover (β-diversity) were evaluated on several spatial scales ranging from Natural Regions (distance between samples 120-420 km) to pitfall traps (40-60 m). A total of 19,885 ground beetles (Carabidae) representing 40 species and 12,669 rove beetles (non-AleocharinaeStaphylinidae) representing 78 species was collected.

Natural succession and clearcutting as drivers of environmental heterogeneity and beta diversity in North American boreal forests.

Clear-cutting alters natural ecosystem processes by reducing landscape heterogeneity. It is the dominant harvesting technique across the boreal zone, yet understanding of how environmental heterogeneity and beta diversity are structured in forest ecosystems and post-clear cut is lacking. We use ground-dwelling arthropods as models to determine how natural succession (progression from deciduous to mixed to coniferous cover types) and clear-cutting change boreal forests, exploring the role of environmental heterogeneity in shaping beta diversity across multiple spatial scales (between-cover types and between-stands of the same cover type (1600 to 8500 m), between-plots (100 to 400 m) and within-plots (20 to 40 m)).

Three new South American species of genus Aphis (Hemiptera: Aphididae) living on species of Euphorbia (Euphorbiaceae).

Three species of Aphis living on species of Euphorbia in Argentina and Chile are described: Aphis tehuelchis Nieto Nafría & López Ciruelos, sp. n., from viviparous females collected in the Argentinean provinces of Santa Cruz and Neuquén, Aphis maulensis Mier Durante & García-Tejero, sp.