Foundation species enhance biodiversity and multifunctionality across many systems; however, whether foundation species patch configuration mediates their ecological effects is unknown. In a 6-month field experiment, we test which attributes of foundation species patch configuration - i.e. patch size, total patch area, perimeter, area-perimeter ratio, or connectivity - control biodiversity, stability and multifunctionality by adding a standardised density of mussel foundation species in patches of 1, 5, 10, 30, 60, 90 or 180 individuals to a southeastern US salt marsh. Over 67% of response variables increased with clustering of mussels, responses that were driven by increases in area-perimeter ratio (33%), decreases in perimeter (29%), or increases in patch size (5%), suggesting sensitivity to external stressors and/or dependence on foundation species-derived niche availability and segregation. Thus, mussel configuration - by controlling the relative distribution of multidimensional patch interior and edge niche space - critically modulates this foundation species' effects on ecosystem structure, stability and function.

Estuarine environments worldwide are among the most threatened habitats due to increased disturbances resulting from coastal infrastructure and rising population densities. Boating activity is a primary disturbance, as it induces biological stress and morphological changes along the coastline. This high-energy environment that boat wakes create has resulted in loss of surrounding oyster reefs and salt marsh vegetation, ultimately leading to shoreline and habitat erosion. Here, we characterize the boat wake climate in the Intracoastal Waterway, assess the bathymetry in this heavily trafficked area, and anticipate the effects of experimental living shorelines (natural breakwall and oyster restoration structures) on facilitating sediment deposition and slowing vegetation retreat. Field observations indicate that boat wakes suspend nearshore sediment and can reach heights greater than 40 cm. A numerical stability model of the breakwalls suggests that the optimal porosity is field-specific. The desired porosity for minimizing lateral displacement is 0.50, while it is 0.18 for maximum energy dissipation, which indicates a need to further investigate this complex problem. These findings demonstrate that boat wakes significantly and regularly disturb estuarine shorelines and may be altering their bathymetry as well as suggest that the design of the breakwalls may be optimized to best counteract this pervasive disturbance.