Plant diversity enhances moth diversity in an intensive forest management experiment

Intensive forest management (IFM) promises to help satisfy increasing global demand for wood, but may come at the cost of local reductions to forest biodiversity. IFM often reduces early seral plant diversity as a result of efforts to eliminate plant competition with crop trees. If diversity is a function of bottom-up drivers, theory predicts that specialists at lower trophic levels (e.g., insect herbivores) should be particularly sensitive to reductions in plant diversity. We conducted a stand-level experiment to test bottom-up controls on moth community structure, as mediated by degrees of forest management intensity. Using a dataset of 12,003 moths representing 316 moth species, moth richness decreased only slightly, if at all, as herbicide intensity increased (P = 0.062); the ’moderate’ treatment, which is most commonly applied in the northwestern USA, was estimated to have 4.72 (± 2.14 SE, P =0.039) fewer species than the control. Structural equation modeling revealed strong suppor...