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Harvard Forest REU Symposium Abstract 2008

• Title: Is glossy buckthorn (Frangula alnus) allelopathic to native New England wetland margin vegetation?
• Author: Amy Mays (Mount Holyoke College)
• Abstract:

  Glossy buckthorn, an exotic shrub from Eurasia, invades upland and mesic sites in New England, forming dense canopies that diminish species richness and reduce the growth and survival of native tree saplings. To test for allelopathy as one mechanism by which buckthorn deleteriously impacts indigenous plant communities, we experimentally propagated three species of native wetland margin shrub [speckled alder (Alnus incana ssp. rugosa), meadowsweet (Spiraea latifolia) and arrowwood viburnum (Viburnum dentatum)] in buckthorn root and leaf mulch as well as in mulch from the native shrub silky dogwood (Cornus amomum). After seven weeks, alder grown in buckthorn root mulch had significantly smaller basal diameter than alder grown in buckthorn leaf or dogwood root or leaf mulch. Therefore, buckthorn’s potential allelopathy to alder may occur primarily through root exudation as opposed to passive leaf drop. Meadowsweet and viburnum, in contrast, showed complex responses to the different mulch treatments, indicating that buckthorn’s effects on native wetland margin shrubs may be highly species-specific, thus altering the composition of plant communities as invasion proceeds.

• Research Category: Invasive Plants, Pests & Pathogens