Response of carabid species and assemblages to forest practices of British Columbia in Engelmann spruce-subalpine fir and interior cedar-hemlock forests

The global extinction rate is currently accelerating at an alarming pace. Habitat loss through the processes of resource extraction, such as forestry are being blamed for much of the loss of biodiversity. In Canada timber extraction is extremely important economically, but modern silvicultural practices are impinging upon constituant and structural features of forest ecosystems, in particular, arthropods. It is important to characterize both the constituant arthropod species of our forests, and their response to forest practices in British Columbia. In this study the effects of clear and partial cutting and shrub removal, and the role of coarse woody debris were tested in Engelmann Spruce Subalpine Fir (ESSF) and Interior Cedar Hemlock (ICH) forests. Ground beetles (Coleoptera: Carabidae) were collected by pitfall traps, and the diversity of assemblages, and the abundance of individual species were described. Richness was calculated by rarefaction; rank abundance (Whittaker) plots and the log series alpha were calculated to characterize dominance structure; and the Shannon-Weiner and Simpson heterogeneity statistics were calculated. Intraspecific treatment effects were tested with the Kruskal-Wallis single-factor analysis of variance by rank and non-parametric multiple comparison tests. A dendrogram was generated to assess forest type and treatment differences. More than 36,000 carabid beetles consisting of 37 species were collected. A new species, now called Bembidion jocylyn Kavanaugh and Erwin, was collected. ESSF sites had more individuals, but fewer species than ICH sites. Logging had a positive effect on diversity but a negative impact on the total number of individuals. The impact of clear cutting in the ESSF endured longer than that in the ICH. Partial cutting reduced the abundance of individuals, but had little effect on overall diversity. Forest species decreased, but did not disappear in clear cuts; species typical of open habitats increased in clear cuts; habitat generalists were common in most sites. Most carabid species were either unaffected or responded favorably to the removal of shrubs: there was an increase in abundance in the ESSF, and in richness in the ICH. Carabid beetles appeared not to have a relationship to coarse woody debris, but there were problems with this third study.Science, Faculty ofZoology, Department ofGraduat