Ecological equivalency of living shorelines and natural marshes for fish and crustacean communities

Donna Marie Bilkovic,Amanda G. Guthrie,Robert E. Isdell,Jessica S. Thompson,Molly Mitchell,Randolph Chambers

doi:10.1016/j.ecoleng.2021.106511

Donna Marie Bilkovic, Amanda G. Guthrie + Show 4 more

Open Access

https://doi.org/10.1016/j.ecoleng.2021.106511

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Abstract

Salt marshes provide valued services to coastal communities including nutrient cycling, erosion control, habitat provision for crustaceans and fish (including juvenile and forage fish), and energy transfer from the detrital based food web to the greater estuarine system. Living shorelines are erosion control structures that recreate natural shorelines, such as fringing marshes, while providing other beneficial ecosystem services. Living shorelines are expected to provide fish and crustacean (nekton) habitat, but few comprehensive studies have evaluated nekton habitat use across a range of living shoreline settings and ages. We sampled the intertidal marsh and subtidal shallow water nekton community at 13 paired living shoreline and reference marsh sites, with living shorelines ranging in age from 2 to 16 years from construction. We compared nekton diversity, nekton community abundance, nekton community biomass, forage abundance, and juvenile abundance at reference marshes and living shorelines. Our results indicate that living shorelines are providing suitable marsh habitat for nekton communities, including juveniles and forage base species. The difference in living shoreline construction (rock sill, soil composition) did not appear to diminish habitat quality in the marsh or in nearshore waters, and rock sills may provide enhanced structural shoreline habitat. Living shorelines have the potential to combat marsh habitat loss and provide resilient nekton nursery habitat.

Highlights

Coastal communities and environments are increasingly threatened by climate change due to loss or hardening of shorelines that results in property damages for coastal residents and reduced habitat availability for aquatic and estuarine species (Gittman et al, 2015; Nicholls et al, 1999)
We found that inundation duration, low marsh, and marsh distance explained some of the variation for juvenile species and that inundation duration, low marsh, and bay mouth distance explained some of the variation in forage base species abundance
Our work shows that living shoreline marsh creation and restoration efforts can supplement efforts to combat marsh habitat loss by providing essential habitat

Summary

Introduction

Coastal communities and environments are increasingly threatened by climate change due to loss or hardening of shorelines that results in property damages for coastal residents and reduced habitat availability for aquatic and estuarine species (Gittman et al, 2015; Nicholls et al, 1999). Coastal development and hard shoreline modifications for erosion control (e.g., bulkhead, riprap revetment) degrade coastal ecosystems and diminish the natural resilience and adaptive capacity of coastal environments (Gittman et al, 2015; Sutton-Grier et al, 2015) Coastal wetlands, such as salt marshes, are vulnerable to anthropogenic stressors, and their loss results in a corresponding reduction in ecosystem functioning and valued services (Gilby et al., 2020). Nekton that forage in the marsh can be prey for commer cially and recreationally valued fish species (Deegan et al, 2002; Kneib, 1986; Laffaille et al, 1998) These sociocultural benefits underscore the key role of salt marshes in supporting estuarine ecosystems, societal resilience, and coastal economies

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