Scientists have studied living shoreline projects to determine how effective they are, particularly compared to bulkheads, at reducing erosion, increasing nearshore biodiversity, and improving coastal resilience. The recent scientific papers listed below are just a few that have proven both the harmful impacts of hardening our shorelines and the positive benefits of living shorelines. 

Morris, R. L., Bilkovic, D. M., Walles, B., & Strain, E. M. A. (2022). Nature-based coastal defence: Developing the knowledge needed for wider implementation of living shorelines. Ecological Engineering, 185, 106798. https://doi.org/10.1016/j.ecoleng.2022.106798

“Climate change and coastal urbanisation are accelerating the demand for protection against erosion and flooding (Kirezci et al., 2020). Rising sea levels and an increased frequency and/or magnitude of storm events has led to growing interest in alternative solutions to grey infrastructure (e.g., seawalls, revetments, dikes) due to unsustainable management costs (Hinkel et al., 2014) and environmental impacts (Bishop et al., 2017; Gittman et al., 2016). Living shorelines that use natural ecosystems either with (“hybrid approach”) or without (“soft approach”) hard stabilising structures for coastal protection may provide several benefits over traditional grey infrastructure (Bilkovic et al., 2017; Sutton-Grier et al., 2015). Topographically complex coastal ecosystems that include dunes, saltmarshes, mangroves, seagrasses and shellfish and coral reefs provide natural coastal protection through wave attenuation, depth-induced wave breaking, and sediment stabilization (Duarte et al., 2013; Narayan et al., 2016; Walles et al., 2015b). These ecosystems can adapt to changes in climate by growing or accreting at the rate of sea level rise (Rodriguez et al., 2014; Sasmito et al., 2016; Walles et al., 2015a), and self-repair after storm events (Gittman et al., 2014). Living shorelines can also provide multiple co-benefits such as supporting biodiversity and fisheries, water filtration, carbon sequestration, social amenity and cultural value (Guthrie et al., 2022; Moody et al., 2022; Smith et al., 2021; Tachas et al., 2021).”

Polk, M. A., Gittman, R. K., Smith, C. S., & Eulie, D. O. (2022). Coastal resilience surges as living shorelines reduce lateral erosion of salt marshes. Integrated Environmental Assessment and Management, 18(1), 82–98. https://doi.org/10.1002/ieam.4447

“A growing suite of research has demonstrated that nature-based shoreline stabilization methods can increase resilience of coastal ecosystems by improving their capacity to return to predisturbance states. Previous work suggests that during hurricanes, living shorelines promote vertical accretion and experience less damage than traditional shoreline stabilization alternatives. This study used in situ real-time kinematic (RTK)-GPS surveys to quantify the resilience (via the lateral change in shore position) of 17 living shoreline sites before and after a Category 1 hurricane event (Hurricane Florence, 2018). By doing so, this study seeks to understand the capacity of living shorelines (marsh with seaward breakwater or sill) to provide storm protection as compared to unaltered natural fringing salt marshes. After Hurricane Florence, living shorelines on average experienced significantly less lateral erosion compared to unprotected control segments (shoreline change rates of 0.015 and −0.31 m year−1, respectively). Living shorelines were found to reduce erosion of fringing marsh edge among projects with a range of installation ages, structural materials, sill widths, and sill heights, and they were able to provide protection from erosion across a range of fetch, scarp, and bottom sediment conditions. This study shows that living shorelines can increase resilience by reducing erosion of fringing salt marshes, promoting lateral building up of shoreline zones during short-term disturbance events, and from their long-term presence.”

Gittman, R. K., Link to external site, this link will open in a new window, Scyphers, S. B., Baillie, C. J., Brodmerkel, A., Grabowski, J. H., Livernois, M., Poray, A. K., Smith, C. S., & Fodrie, F. J. (2021). Reversing a tyranny of cascading shoreline protection decisions driving coastal habitat loss. Conservation Science and Practice, 3(9). https://doi.org/10.1111/csp2.490

“Shoreline hardening is a major driver of biodiversity and habitat loss in coastal ecosystems yet remains a common approach to coastal management globally. Using surveys of waterfront residents in North Carolina, USA, we sought to identify factors influencing individual shore-protection decisions and ultimately impacting coastal ecosystems, particularly coastal wetlands. We found that neighboring shore condition was the best predictor of respondent shore condition. Respondents with hardened shorelines were more likely to have neighbors with hardened shorelines, and to report that neighbors influenced their shore-protection choices than respondents with natural shorelines. Further, respondents who expressed climate-change skepticism and preference for shoreline hardening were opposed to shoreline-hardening restrictions. Despite preferring hardening, respondents ranked wetlands as highly valuable for storm protection and other ecosystem services, suggesting a disconnect between the ecological knowledge of individuals and social norms of shore-protection decisions. However, our results also suggest that efforts to increase the installation of living shorelines have the potential to conserve and restore important coastal habitats and support biodiversity along shorelines that may otherwise be degraded by hardening. Further, encouraging waterfront-property owners who have adopted living shorelines to recommend them to neighbors may be an effective strategy to initiate and reinforce pro-conservation social norms.”

Isdell, R. E., Bilkovic, D. M., Guthrie, A. G., Mitchell, M. M., Chambers, R. M., Leu, M., & Hershner, C. (2021). Living shorelines achieve functional equivalence to natural fringe marshes across multiple ecological metrics. PeerJ, 9, e11815. https://doi.org/10.7717/peerj.11815

“Nature-based shoreline protection provides a welcome class of adaptations to promote ecological resilience in the face of climate change. Along coastlines, living shorelines are among the preferred adaptation strategies to both reduce erosion and provide ecological functions. As an alternative to shoreline armoring, living shorelines are viewed favorably among coastal managers and some private property owners, but they have yet to undergo a thorough examination of how their levels of ecosystem functions compare to their closest natural counterpart: fringing marshes. Here, we provide a synthesis of results from a multi-year, large-spatial-scale study in which we compared numerous ecological metrics (including habitat provision for fish, invertebrates, diamondback terrapin, and birds, nutrient and carbon storage, and plant productivity) measured in thirteen pairs of living shorelines and natural fringing marshes throughout coastal Virginia, USA. Living shorelines were composed of marshes created by bank grading, placement of sand fill for proper elevations, and planting of S. alterniflora and S. patens, as well as placement of a stone sill seaward and parallel to the marsh to serve as a wave break. Overall, we found that living shorelines were functionally equivalent to natural marshes in nearly all measured aspects, except for a lag in soil composition due to construction of living shoreline marshes with clean, low-organic sands. These data support the prioritization of living shorelines as a coastal adaptation strategy.”

Polk, M. A., & Eulie, D. O. (2018). Effectiveness of Living Shorelines as an Erosion Control Method in North Carolina. Estuaries and Coasts, 41(8), 2212–2222. https://doi.org/10.1007/s12237-018-0439-y

“Living shorelines are a shoreline stabilization strategy encompassing a range of vegetative to structural materials and serve as an alternative approach to the use of structures like bulkheads, which are known to aggravate erosion. This study sought to assess the performance of living shorelines with sills, with respect to shoreline protection, by determining shoreline change rates (SCR) using geospatial analysis. Shoreline surveys were conducted using a real-time kinematic (RTK)-GPS unit at a total of 17 living shoreline projects and nine control segments at 12 sites along the coast of North Carolina. Of the 17 living shoreline project segments, 12 exhibited a reduction in the rate of erosion; of those 12, six were observed to be accreting. This study supports the convention that living shorelines can reduce the rate of erosion and potentially restore lost shore zone habitat.”

Gittman, R. K., Peterson, C. H., Currin, C. A., Joel Fodrie, F., Piehler, M. F., & Bruno, J. F. (2016). Living shorelines can enhance the nursery role of threatened estuarine habitats. Ecological Applications, 26(1), 249–263. https://doi.org/10.1890/14-0716

“Coastal ecosystems provide numerous services, such as nutrient cycling, climate change amelioration, and habitat provision for commercially valuable organisms. Ecosystem functions and processes are modified by human activities locally and globally, with degradation of coastal ecosystems by development and climate change occurring at unprecedented rates. The demand for coastal defense strategies against storms and sea-level rise has increased with human population growth and development along coastlines worldwide, even while that population growth has reduced natural buffering of shorelines. Shoreline hardening, a common coastal defense strategy that includes the use of seawalls and bulkheads (vertical walls constructed of concrete, wood, vinyl, or steel), is resulting in a “coastal squeeze” on estuarine habitats. In contrast to hardening, living shorelines, which range from vegetation plantings to a combination of hard structures and plantings, can be deployed to restore or enhance multiple ecosystem services normally delivered by naturally vegetated shores. We quantified the effectiveness of (1) sills with landward marsh (a type of living shoreline that combines marsh plantings with an offshore low-profile breakwater), (2) natural salt marsh shorelines (control marshes), and (3) unvegetated bulkheaded shores in providing habitat for fish and crustaceans (nekton). Sills supported higher abundances and species diversity of fishes than unvegetated habitat adjacent to bulkheads, and even control marshes. Sills also supported higher cover of filter-feeding bivalves (a food resource and refuge habitat for nekton) than bulkheads or control marshes. Sills provide added structure and may provide better refuges from predation and greater opportunity to use available food resources for nekton than unvegetated bulkheaded shores or control marshes. Our study shows that unlike shoreline hardening, living shorelines can enhance some ecosystem services provided by marshes, such as provision of nursery habitat.”

Rodriguez, A. B., Fodrie, F. J., Ridge, J. T., Lindquist, N. L., Theuerkauf, E. J., Coleman, S. E., Grabowski, J. H., Brodeur, M. C., Gittman, R. K., Keller, D. A., & Kenworthy, M. D. (2014). Oyster reefs can outpace sea-level rise. Nature Climate Change, 4(6), Article 6. https://doi.org/10.1038/nclimate2216

“In the high-salinity seaward portions of estuaries, oysters seek refuge from predation, competition and disease in intertidal areas1,2, but this sanctuary will be lost if vertical reef accretion cannot keep pace with sea-level rise (SLR). Oyster-reef abundance has already declined ∼85% globally over the past 100 years, mainly from over harvesting, making any additional losses due to SLR cause for concern. Before any assessment of reef response to accelerated SLR can be made, direct measures of reef growth are necessary. Here, we present direct measurements of intertidal oyster-reef growth from cores and terrestrial lidar-derived digital elevation models. On the basis of our measurements collected within a mid-Atlantic estuary over a 15-year period, we developed a globally testable empirical model of intertidal oyster-reef accretion. We show that previous estimates of vertical reef growth, based on radiocarbon dates and bathymetric maps, may be greater than one order of magnitude too slow. The intertidal reefs we studied should be able to keep up with any future accelerated rate of SLR and may even benefit from the additional subaqueous space allowing extended vertical accretion.”