1. Field Experiments and Meta-analysis Reveal Wetland Vegetation as a Crucial Element in the Coastal Protection Paradigm.
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Silliman, Brian R., He, Qiang, Angelini, Christine, Smith, Carter S., Kirwan, Matthew L., Daleo, Pedro, Renzi, Julianna J., Butler, Jack, Osborne, Todd Z., Nifong, James C., and van de Koppel, Johan
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SHORELINE monitoring , *WETLAND restoration , *SALT marsh plants , *TYPHA , *COASTAL changes , *WETLANDS , *PLANT biomass , *COASTAL wetlands - Abstract
Increasing rates of sea-level rise and wave action threaten coastal populations. Defense of shorelines by protection and restoration of wetlands has been invoked as a win-win strategy for humans and nature, yet evidence from field experiments supporting the wetland protection function is uncommon, as is the understanding of its context dependency. Here we provide evidence from field manipulations showing that the loss of wetland vegetation, regardless of disturbance size, increases the rate of erosion on wave-stressed shorelines. Vegetation removal (simulated disturbance) along the edge of salt marshes reveals that loss of wetland plants elevates the rate of lateral erosion and that extensive root systems, rather than aboveground biomass, are primarily responsible for protection against edge erosion in marshes. Meta-analysis further shows that disturbances that generate plant die-off on salt marsh edges generally hasten edge erosion in coastal marshes and that the erosion protection function of wetlands relates more to lateral than vertical edge-erosional processes and is positively correlated with the amount of belowground plant biomass lost. Collectively, our findings substantiate a coastal protection paradigm that incorporates preservation of shoreline vegetation, illuminate key context dependencies in this theory, and highlight local disturbances (e.g., oil spills) that kill wetland plants as agents that can accelerate coastal erosion. • Experimental removal of salt marsh vegetation enhances lateral erosion • Belowground biomass was the plant trait responsible for resisting erosion • Meta-analysis shows that plant die-off generally hastens erosion of salt marshes • Findings support a coastal protection paradigm that incorporates coastal wetlands Silliman et al. employ field experiments and meta-analysis to show that, contrary to recent lab work, salt marsh plants protect shorelines from erosion. This work substantiates a coastal protection paradigm that incorporates coastal wetlands and highlights disturbances that kill marsh plants as major forces that can indirectly drive coastal erosion. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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