Response of ground beetle (Carabidae) assemblages to logging history in northern hardwood–hemlock forests

We quantified differences in ground beetle (Coleoptera: Carabidae) communities in relation to forest management practices and historic forest cover changes in hardwood–hemlock forests of the north central United States. Beetles were sampled with pitfall traps in 1996 and 1997 and compared among three forest types: old-growth, and post-logging uneven- and even-aged forests. Non-metric multidimensional scaling ordination was used to assess compositional differences among forest types for 39 carabid species (43,483 individuals), which revealed distinct differences in beetle assemblages among forest types. Coarse woody debris, snag volume, gap area, understory vegetation and forest floor depth were significantly correlated with ordination axes suggesting that these variables are critical in structuring the beetle communities. Several of the species significantly associated with old-growth forests, like Carabus sylvosus, are known to favor forest habitats, whereas species commonly found in open habitats, such as Carabus nemoralis, had stronger affiliations with managed forests. Comparisons of northern hardwood–hemlock forest distribution from pre-Euroamerican settlement with current distributions reconstructed using the Forest Inventory and Analysis database indicate that old-growth habitat has declined to <1% of its original extent in this region. At the landscape level, these data suggest that the abundance of carabid species that prefer old-growth forest conditions has undergone broad-scale decline.