Epigaeic Beetles Research Articles

Salvage Logging, Edge Effects, and Carabid Beetles: Connections to Conservation and Sustainable Forest Management

We used pitfall traps to study the effects of fire and salvage logging on distribution of carabid beetles over a forest disturbance gradient ranging from salvaged (naturally burned and subsequently harvested) to unsalvaged (naturally burned and left standing). Significantly more carabids were caught in the salvaged forest and the overall catch decreased steadily through the edge and into the unsalvaged forest. We also noted a strong negative correlation between carabid abundance and percent vegetation cover. Beetle diversity as measured through rarefaction was significantly greater at the edge relative to both the unsalvaged and salvaged forest. This stand level study suggests that the amount of edge habitat created by salvage logging has significant implications for recovery of epigaeic beetle assemblages in burned forests by inflating the abundance of “open habitat” species in the initial communities. Carabid beetle responses to salvage logging can differ from responses to harvesting in unburned boreal forest suggesting that management of postfire forests requires special consideration.

Fire residuals as habitat reserves for epigaeic beetles (Coleoptera: Carabidae and Staphylinidae)

We studied litter-dwelling beetles (Coleoptera: Carabidae and Staphylinidae) in residual patches of unburned forests (fire residuals) left by two natural wildfires in high-elevation coniferous forests in western Alberta, Canada. Fire residuals were wet, late-successional patches of fir and spruce stands, and served as refugia for populations of forest-dwelling beetle species. The largest fire residuals contained older living trees than the mature forest surrounding the burnt areas. Pterostichus empetricola, a glacial relict beetle species, was associated only with habitats provided by the fire residuals. Although there was no relationship between the size of fire residuals and beetle diversity or activity-abundance, more Nebria crassicornis were collected per trap in larger residuals, suggesting dependence of this species on late-seral attributes present within the largest residuals. Conservation of habitats equivalent to fire residuals in managed forests will likely contribute to landscape continuity and preservation of faunal elements common in wildfire-origin landscapes.

Landscape heterogeneity in relation to variations in epigaeic beetle diversity of a Mediterranean ecosystem. Implications for conservation.

Habitat heterogeneity is a determinant cause of biological diversity in natural ecosystems, and therefore its preservation should be a priority when planning conservation strategies. Sierra de Baza, in southern Spain, is a protected natural area in which biotopes of particular interest still remain, but extensive afforestation with pine species has been widespread in recent decades and, in some cases, continues. The aim of this paper is to test the role of habitat heterogeneity at the landscape scale in generating epigaeic beetle diversity in Sierra de Baza. After two-year-long cycles of sampling epigaeic beetles, differences in local diversity at nine sites, and differences in the pattern of species turnover between sites, have been measured. Local communities differed among sites, 74% of the species being scarce (less than 0.41% of total beetle abundance), and thus species replacement differed markedly between sites. Comparisons between habitat types showed that the planted pine forests support less diverse fauna. Our results identify habitat heterogeneity at the landscape scale as the main source of epigaeic beetle diversity at the landscape scale, practices such as extensive afforestation diminishing landscape heterogeneity and consequently local beetle diversity. Preservation of landscape heterogeneity should be encouraged for an adequate beetle biodiversity conservation.