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Harvard Forest Symposium Abstract 2009

  • Title: Is invasive glossy buckthorn (Frangula alnus) allelopathic to native New England wetland margin vegetation?
  • Primary Author: Kristina Stinson (University of Massachusetts - Amherst )
  • Additional Authors: Amy Mays (Mount Holyoke College)
  • Abstract:

    Glossy buckthorn (Frangula alnus), an invasive shrub from Eurasia, colonizes both upland and mesic sites in New England, USA, reducing the growth and survival of native tree saplings and lowering species richness. Although a generalist, buckthorn thrives particularly well along river, pond, and wetland margins, which are traditional habitat for speckled alder (Alnus incana ssp. rugosa), a native nitrogen-fixing shrub. As buckthornís dense, monospecific growth is typical of allelopaths, we wondered whether it chemically suppresses the growth of alder and other indigenous shrubs. We thus propagated three native shrub species, including alder and meadowsweet (Spiraea latifolia), in invasive buckthorn and native dogwood (Cornus amomum) root and leaf mulch. After seven weeks, alder grown in buckthorn root demonstrated significantly smaller basal diameter than alder grown in buckthorn leaf or other mulches. Therefore, putative buckthorn allelopathy to alder likely occurs through root exudation instead of leaf litter effects. Meadowsweet grown in buckthorn mulch, in contrast, was taller, thicker, and had more numerous leaves than meadowsweet grown in native mulch. These species-specific effects point to allelopathy as a mechanism by which buckthorn changes the structure of native plant communities.

  • Research Category: Invasive Plants, Pests & Pathogens, Physiological Ecology, Population Dynamics, and Species Interactions