The legacy of timber harvest: Do patterns of species dominance suggest recovery of lepidopteran communities in managed hardwood stands?

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Patterns of local and regional dominance within species assemblages can be used to infer the legacy of disturbance in managed systems. Specifically, highly disturbed communities are expected to share the same dominant species across environmental gradients, while recovery from disturbance should be correlated with a differentiation among the dominant suite of species among sites. We tested this hypothesis using moth communities sampled from 20 forest stands within three watersheds managed for complete timber harvest 60 years prior. Specifically, we (1) compared the species-abundance distributions for all moths sampled from the forests, (2) used ordination and indicator species analysis to assess whether the same taxa were most dominant within each forest stand, and (3) tested whether dominant taxa were disproportionately niche generalists compared to all species sampled from the larger species pools within each watershed. With only a single significant exception, moth communities within the forest stands shared the log-normal species-abundance distribution. Ordination suggested some evidence of divergence in species dominance among individual forest stands, but differences were not based on watershed identity or spatial proximity. Few dominant species appeared to display a high level of fidelity to any particular stand or watershed in the region. Finally, dominant taxa were not disproportionately niche generalists, but this result was largely driven by the absence of niche specialists from the entire forested landscape. Thus, we suggest that the moth communities from this managed forest system still bear a clear legacy of timber management more than 60 years post-harvest. Shifts in dominant moth taxa among forest stands may be largely idiosyncratic in nature.