The effects of prescribed fire severity and time post-burn on beetle assemblages in a temperate deciduous forest.

Fire is increasingly used as a management tool in temperate deciduous forests, but the effects of fire on arthropods in these systems remain unclear. Here, we used flight-intercept traps to sample beetle assemblages (Coleoptera) in portions of a temperate deciduous forest of eastern North America subjected to either a higher-severity burn, a lower-severity burn, or no burn. We collected beetles immediately following the burns and for up to 2 yr post-burn. Average (±SE) beetle abundance did not differ between the higher-severity (45 ± 13) and lower-severity (55 ± 26) burns but was 2× higher in the burned sites vs. the unburned site (25 ± 6). Likewise, traps in the 2 burned sites captured a similar number of beetle species (17 ± 0.5 and 15 ± 0.5, respectively), and more species than in the unburned site (12 ± 0.4). These patterns were consistent over time post-burn in all sites. Beetle composition also consistently differed between the burned and unburned sites; bark and ambrosia beetles (Curculionidae: Scolytinae) were the most abundant groups in the burned sites. Species turnover (beta diversity) was highest in the unburned site. Eleven species were associated with specific combinations of burn treatment and time post-burn. The results suggest that fire severity and time post-burn play key roles in structuring local beetle assemblages and that longer fire intervals (≥3 yr) are required to facilitate recovery. Measuring beetle responses to fire in temperate deciduous forests improves our understanding of the effects of disturbance-based management on local biodiversity.