Trophic cascades have been observed in numerous ecosystems and are known to have positive impacts on restoration outcomes. Yet, the role that trophic cascades and predators play in facilitating the recovery of coastal wetland ecosystem properties relative to bottom-up factors is unclear. Over a two-year period, I altered the presence/absence of a crustacean predator in New England coastal salt marshes to evaluate whether trophic cascades can lead to the restoration of altered ecosystem processes and used path analyses to determine the relative bottom-up and top-down contributions to observed changes (Moore & Schmitz, submitted to Restoration Ecology).
Predator removal led to an attendant change in aboveground biomass and the rate of soil nitrogen absorption at one study site while restoring this predator returned these properties to control conditions. Across all study sites, changes in ecosystem processes were driven by a combination of bottom-up and top-down factors. These results suggest that wetland restoration in southern New England may benefit from incorporating both top-down and bottom-up features for improved recovery of ecosystem functions. |