Analysis of ground beetle (Coleoptera: Carabidae) diversity in inland temperate rainforest habitats in British Columbia, Canada

Ground beetle (Coleoptera: Carabidae) diversity was measured in the Ancient Rainforest in northern British Columbia, Canada. This inland habitat is dominated by western redcedar, and shares many environmental features with coastal rainforests, making it an island habitat that may host different species than the surrounding area. The goal was to obtain an accurate estimation of the carabid species present in the ecosystem, and to construct a baseline for future bioindication surveys. Clear cuts were compared with both disturbed and undisturbed old growth sites, to determine biodiversity and species composition in those site types. There were three replicates of each site type, with ten trap rings per replicate. Each trap ring consisted of three modified Nordlander pitfall traps. The traps were dug in for two weeks, and propylene glycol was added when the traps were opened. Traps were emptied every two weeks, then sorted and identified as specifically as possible using morphological keys. Scaphinotus marginatus was dominant in all sites, especially the old growth. Trechus chalybeus and Pterostichus spp. were also present in all sites, though at a lower frequency. More beetles were caught per trap in old growth sites than in clear cut sites, but there was no observed difference between the disturbed and undisturbed old growth sites. Traps in clear cut sites had a larger proportion of bycatch, with slugs being common in these sites. Spiders were also present in large numbers in all treatment types. The dominance of the easily recognizable S. marginatus in the old growth sites may demonstrate its suitability as a bioindicator species. These results will be used for future bioindicative analysis.