Restoration has been elevated as an important strategy to reverse the decline of coastal wetlands worldwide. Current practice in restoration science emphasizes minimizing competition between out-planted propagules to maximize planting success. This paradigm persists despite the fact that foundational theory in ecology demonstrates that positive species interactions are key to organism success under high physical stress, such as recolonization of bare substrate. As evidence of how entrenched this restoration paradigm is, our survey of 25 restoration organizations in 14 states in the United States revealed that >95% of these agencies assume minimizing negative interactions (i.e., competition) between outplants will maximize propagule growth. Restoration experiments in both Western and Eastern Atlantic salt marshes demonstrate, however, that a simple change in planting configuration (placing propagules next to, rather than at a distance from, each other) results in harnessing facilitation and increased yields by 107% on average. Thus, small adjustments in restoration design may catalyze untapped positive species interactions, resulting in significantly higher restoration success with no added cost. As positive interactions between organisms commonly occur in coastal ecosystems (especially in more physically stressful areas like uncolonized substrate) and conservation resources are limited, transformation of the coastal restoration paradigm to incorporate facilitation theory may enhance conservation efforts, shoreline defense, and provisioning of ecosystem services such as fisheries production.
Salt marsh restoration based on two different designs of planting transplants: (1) In clumped treatments, nine transplant plugs were planted in the middle of each plot so that all plugs were touching. (2) In dispersed treatments, nine plugs were planted at equal distances from each other (50 cm in all directions). Trans- plant plugs were 10 × 10 × 10 cm and consisted of the dominant marsh grass Spartina alterniflora
|Climate change impacts||Effect of Nbs on CCI||Effect measures|
|Biomass cover loss||Positive||For the planted saltmarsh species: Aboveground biomass % survivorship mean total plot stem density (including all stems in original plantings and emergent runners and thus a measurement of clump expansion) maximum expansion / maximal runner length (reflecting dispersal potential)|
Gulf of Mexico at Fort DeSoto, Tampa, Florida (N 27°36′56′′, W 82°44′09′′)