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Harvard Forest Symposium Abstract 2005

• Title: Exotic plant invasion degrades local mycorrhizal association, alters community succession and limits restoration
• Primary Author: Kristina Stinson (University of Massachusetts - Amherst )
• Additional Authors: John Klironomos (University of Guelph)
• Abstract:

  Many ecosystems are susceptible to invasion by exotic organisms, but the consequences of the invasion process on the functioning of ecosystems are mostly unknown. Here, we report on a novel mechanism by which a common plant invader of eastern North American forests, Alliaria petiolata, can negatively impact native forest plants and can alter the trajectory of succession of the forest community. Once established, Alliaria degrades populations of mycorrhizal fungi in the soil and negatively affects plant growth (Fig. 1). Since late successional plants are highly mycorrhizal dependent, degradation of mycorrhizal fungi limits the ability of these plants to establish and grow. In contrast, early- and mid-successional weedy plants are less mycorrhizal dependent, and are less affected by Alliaria (Fig. 2). Attempts to restore the ecosystem by removing the invader and adding new mycorrhizal fungi does not reverse this effect, as the active compounds by Alliaria are highly persistent in soil (Fig. 3). Our results suggest that invasion by Alliaria could alter the successional dynamics of forest ecosystems by selectively promoting the growth of early successional weedy plants.

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