Effects of Competition, Disturbance, and Herbivory on Salicornia Europaea
1987
Ellison, Aaron M.
The effects of interspecific competition, physical disturbance, and insect herbivory on the distribution and abundance of Salicornia europaea in a New England salt marsh were studied using manipulative field experiments. In New England salt marsh plant communities, S. europaea is restricted to disturbance generated patches. S. europaea was unable to colonize successfully low—marsh habitats that were flooded daily by tides, because seedlings germinating in these areas could not anchor in soft substrate and were easily uprooted. In high—marsh habitats, S. europaea seeds reliably colonized recently created patches because the seed's hairy coat bound to the plant debris that created the patches. S. europaea was successful in naturally occurring and artificially maintained patches. However, it was rapidly outcompeted for light by perennials in undisturbed areas and eventually was overgrown by perennials growing into the patches. When the perennial canopy was removed, S. europaea increased in biomass and fecundity relative to conspecifics that were beneath the perennial canopy. S. europaea, however, was attacked by insect herbivores more frequently in patches than beneath the perennial canopy and this herbivore pressure reduced survivorship in patches to approximately the same level as beneath the perennial canopy. Interactions among physical disturbance, seed dispersal patterns, interspecific competition, and herbivory appear to be major factors controlling patterns of distribution and abundance of Salicornia in New England salt marsh plant communities.
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