Do seasonal temperatures, species traits and nearby timber harvest predict variation in moth species richness and abundance in unlogged deciduous forests?

Abstract

The present study aimed to determine whether the activity of lepidopteran communities in stands adjacent to timber harvest was more variable than that for communities in unlogged landscapes. Moths were sampled using light traps in 11 unlogged forest stands in Morgan-Monroe State Forest (Indiana, U.S.A.) in 2007 (before harvest) and then again from 2009 to 2012 (post-harvest within nearby stands). Mean winter low temperatures were correlated with higher levels of variation in species richness across all forest stands. Greater variation in species richness was also correlated with the occurrence of nearby harvests. Colder winters depressed species richness of forest moths across all forest stands. Unlogged stands within 100 m of patch cuts or shelterwood cuts gained and lost species at a greater rate than stands adjacent to unlogged forest. Species specialized to a single host were subject to the most significant variability and many specialists experienced ±50% change in abundance over 5 years. Timber harvest created a disturbance footprint that extended beyond the managed forest concession. Moth species with a specialized larval diet appeared to be most vulnerable to the indirect effects of timber harvest. Small logging concessions may change diversity at larger scales than presumed.