Fire and Acorn Predation Interact to Affect Oak Regeneration

Background Seed predators cause localized losses exceeding 90% in oak forests of the eastern US. Acorn predators such as acorn weevils, Conotrachelus posticatus, C. naso, and Barypeithes pellucidus (an introduced species), the sap beetle, Stelidota octomaculata, and the acorn moth, Valentinia glandulella, are primary (feeding and breeding in intact seed) and/or secondary pests (feeding and breeding in damaged seed), consuming acorn cotyledons and damaging radic1es. Depending on the predator involved, the acorn may produce a seedling, but with poor survival and growth. These insects are closely associated with soil and litter, and as such may vector and/or create infection courts for potentially pathogenic microorganisms. Additionally, soiVlitter arthropods are strongly affected by factors such as stand composition, litter depth, and soil type and depth, which influences their local distribution and significance, and which can be manipulated to some extent with prescription burning. In spite of their impact, little is known about the biology and ecology, life history, and host range of this herbivore guild. Furthermore, there is little information on species composition and distribution in the Appalachian region. This knowledge could facilitate development of sampling protocols which would enable us to determine the extent to which these insects are impacting acorn viability, and the extent to which prescribed fire impacts this herbivore guild. Objectives My objectives are to characterize the species composition and relative abundance of acorn predators as they relate to site characteristics and fire regime, using existing sites in the Morehead and Stanton Districts of the DBNF. My results will allow a better understanding of the impact of seed predators on oak regeneration in the region. On burned and non-burned sites, my specific objectives are to: I) determine the species composition of the herbivores responsible for acorn predation, 2) assess the extent to which these predators impact acorn germination, and 3) assess potential fire-induced, species-specific differences in acorn phytochemistry (specifically tannins and carbohydrates) which could influence susceptibility to predation.