Can Co-Occurring Secondary Foundation Species Increase Restoration Success?

Abstract

Salt marshes, some of the most productive environments in the world, are consistently threatened by anthropogenic disturbance. To conserve and restore salt marsh ecosystems more efficiently, we need to understand the context of, and harness, facilitative species interactions to increase their chance of success. We examined the effects of co-occurring secondary foundation species, (Crassostrea virginica and Geukensia demissa) on marsh plant restoration (Spartina alterniflora), seeking to test whether C. virginica provided associational predator defense to G. demissa thereby increasing survivorship and enhancing the overall beneficial effect on S. alterniflora. In our experimental transplantation, we show that an oyster shell canopy fails to produce this synergistic effect or meaningfully reduce predation on the benthic G demissa. We also present evidence of Littoraria irrorata preferentially grazing S. alterniflora associated with G. demissa while avoiding C. virginica associated treatments.