In each of these successive interventions, the 19 m of forest lef

In each of these successive interventions, the 19 m of forest left intact in the prior intervention will be harvested, leaving 5 m of cut forest with 0% retention with adjacent 7 m partial cuts strips where retention is 66% (Fig. 1). We compared the effects of clear cuts (5% retention), shelterwood (50% retention) and multicohort harvests (66% retention) to uncut stands (100% retention) as a control. Each harvesting treatment was replicated 5 times. Beetles were collected using pitfall traps. We placed a total

of 9 pitfall traps within each experimental stand. In partial cut stands, we placed 3 traps along the machine corridor with 0% retention, 3 traps within partial cut retention strips (either 50% or 66% retention) SB431542 in vitro and 3 traps with uncut retention strip (100% retention). Within uncut and clearcut stands, we placed the 9 pitfall traps in an identical spatial pattern to that used in partial cut stands.

All traps were charged with approximately 200 ml of Prestone® trans-isomer molecular weight pet-safe antifreeze (propylene-glycol), which served as a preservative and new antifreeze was added as needed. Traps were covered with elevated plastic lids to prevent flooding from rain. Traps were collected approximately every three weeks between 5/23 and 8/17 in 2009 and between 5/25 and 7/25 in 2010. All ground beetle specimens were identified to species using keys developed by Lindroth (1961, 1963, 1966, 1968, 1969). We pooled the three traps located in each machine corridor, partial cut or uncut retention strip, resulting in 120 samples (3 aggregated samples of three pitfall

traps corresponding to within stand heterogeneity× 4 harvesting treatments× 5 replicates× 2 sampling years). We evaluated changes in overall catch rate Urease (beetles/day) using a linear mixed model where harvesting treatment, position within stand (machine corridor, partial cut retention strip or uncut retention strip) and sampling year were fixed, main effects. All two-way and three-way interactions were included in the model and experimental blocks and individual sampling site (subjects) were used as random effects. We compared all fixed effects in the model by using Wald t-tests to compare differences in individual betas (or slopes) for fixed effects with a statistical reference condition. For our comparison, we used uncut control stands and uncut vegetation corridors that were sampled in 2009 as the reference condition for the linear mixed model. We used the nlme package to analyze this mixed model in R.2.12 (R Development Core Team, 2011). Catch rates were transformed using a square-root transformation to meet assumptions of normality in the model. We used individual-based rarefaction to estimate species richness among specific treatment combinations based on results of the mixed model for catch rate.

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