Hemlock Removal Experiment - Salamander Response

Despite reductions in prices, pre-emptive salvage logging of eastern hemlock stands has increased since the arrival of eastern hemlock woolly adelgid (Adelges tsugae, HWA) into this region. The microenvironmental changes associated with eastern hemlock loss have been found to be even more severe than when stands are lost to logging due to HWA infestation. This study assessed the effects of a commercial logging operation on two 90m x 90m (0.8 ha) plots, conducted in the winter of 2004-2005, on eastern redback salamander (Plethodon cinereus) relative abundance within the Simes tract at Harvard Forest. Over the past seven seasons (fall 2003 - fall 2005; excluding winter) I have been monitoring eastern redback salamander relative abundance using artificial cover objects (ACOs). The objectives of this study were 1) to assess whether logging has an impact on redback relative abundance at a plot level 2) to assess whether logging in isolated plots has an impact on relative abundance throughout the entire Simes tract 3) to assess whether redback relative abundance is stable over two years.Redback relative abundance in spring 2005 was 660% lower than in spring 2004 in logged plots, while in unlogged plots there was a 4% increase in redback relative abundance in spring 2005 versus spring 2004 (one-way ANOVA; df = 7, F = 6.21, p less than 0.05). Between fall 2004 and spring 2005 redback relative abundance decreased by 727% in the logged plots, compared to only a 29% decrease in unlogged plots (one-way ANOVA; df = 7, F = 10.51, p less than 0.05). Plots adjacent to logged plots had a significantly higher increase in redback relative abundance in spring 2005 versus spring 2004 than those not adjacent to the logged plots (one-way ANOVA; df = 5, F = 8.64, p less than 0.05). There was no significant difference in redback relative abundance in all plots in spring 2004 versus spring 2005 (one-way ANOVA; df = 15, F = 0.20, p = 0.665), or in fall 2004 versus spring 2005 (one-way ANOVA; df = 15, F = 0.03, p = 0.859). Further, the annual difference in redback relative abundance in the fall over three years indicates that the redback population has been extremely stable during this period (one-way ANOVA; df = 23, F = 0.05, p = 0.954)