We summarized existing information on how nature-based solutions (NBS), actions working with nature to meet society’s and nature’s needs, help boost coastal resilience. We searched through 37,000 scientific articles published since 1980 on the performance of NBS for coastal protection in salt marsh, shellfish reef, coral reef, kelp, seagrass, and mangrove ecosystems. Synthesis findings highlight the current state of knowledge on NBS for coastal protection and help direct future NBS-related research.
Why We Care Impacts from human activities threaten the capacity of ecosystems to protect coastal communities from hazards like flooding and erosion. Human interventions aim to buffer or overcome these threats by providing physical protection for existing coastal infrastructure and communities. These interventions, which involve working with nature to achieve societal, biodiversity, and resilience benefits, are referred to as nature-based solutions (NBS). NBS for coastal protection include habitat restoration and creation, structure addition (artificial or natural), retrofitting gray infrastructure, or modifying morphology or sediment. Despite the popularity of NBS for coastal protection, gaps remain in our understanding of whether such interventions perform as intended.
What We Did To help fill these knowledge gaps, we synthesized existing evidence from primary literature since 1980 on how NBS for coastal protection perform across a suite of ecological, physical, social, and economic outcomes. Our state of the science assessment focused on six coastal ecosystems: salt marsh, shellfish reef, coral reef, seagrass, mangrove, and kelp.
We created an inventory of knowledge, “mapping” what is known and identifying information gaps. We used a method called “systematic mapping,” which is a technique that summarizes the distribution and abundance of evidence (e.g., published data or findings on a topic) from primary and secondary literature.
The project team included scientists from the NOAA Central Library, NOAA Office for Coastal Management, Duke University, North Carolina State University, and East Carolina University.
What We Did/Are Doing To help fill these knowledge gaps, we synthesized existing evidence from primary literature since 1980 on how NBS for coastal protection perform across a suite of ecological, physical, social, and economic outcomes. Our state of the science assessment focused on six coastal ecosystems: salt marsh, shellfish reef, coral reef, seagrass, mangrove, and kelp.
We created an inventory of knowledge, “mapping” what is known and identifying information gaps. We used a method called “systematic mapping,” which is a technique that summarizes the distribution and abundance of evidence (e.g., published data or findings on a topic) from primary and secondary literature.
The project team included scientists from the NOAA Central Library, NOAA Office for Coastal Management, Duke University, North Carolina State University, and East Carolina University.
What We Found NBS for coastal protection were most often implemented in salt marshes (45%), mangrove forests (26%), and shellfish reefs (20%), whereas there were fewer NBS studies in seagrass meadows (4%), coral reefs (4%), or kelp beds (< 1%). Performance evaluations of NBS were typically conducted using observational or experimental methods at local spatial scales and over short temporal scales (< 1 year to 5 years). Evidence clusters existed for several types of NBS interventions, including restoration and addition of structures (e.g., those consisting of artificial, hybrid, or natural materials), yet evidence gaps existed for NBS interventions like alteration of invasive species. Evaluations of NBS performance commonly focused on ecological (e.g., species and population, habitat, community) and physical (e.g., waves, sediment and morphology) outcomes, whereas pronounced evidence gaps existed for economic (e.g., living standards, capital) and social (e.g., basic infrastructure, health) outcomes.
Benefits of Our Work
This systematic map highlights evidence clusters and evidence gaps related to the performance of active NBS interventions for coastal protection in shallow, biogenic ecosystems. The synthesized evidence base will help guide future research and management of NBS for coastal protection so that active interventions can be designed, sited, constructed, monitored, and adaptively managed to maximize co-benefits. Promising avenues for future research and management initiatives include implementing broad-scale spatial and temporal monitoring of NBS in multidisciplinary teams to examine not only ecological and physical outcomes but also economic and social outcomes, as well as conducting further synthesis on evidence clusters that may reveal measures of effect for specific NBS interventions. Since NBS can deliver multiple benefits, measuring a diverse suite of response variables, especially those related to ecosystem function, as well as social and economic responses, may help justify and improve societal benefits of NBS. Such an approach can help ensure that NBS can be strategically harnessed and managed to meet coastal protection goals and provide co-benefits for nature and people.
Next Steps
- The findings from the systematic map will help guide future research directions to fill notable knowledge gaps, which may include:
- Monitoring of NBS performance over broad spatial (e.g., multiple projects over broad spatial scales) and temporal scales, since much of the current evidence base stems from local and short-term studies.
- Using the systematic map for a systematic review. There is likely sufficient evidence on the ecological and physical performance of NBS in salt marsh, mangrove, and shellfish reef ecosystems to conduct quantitative syntheses. There may also be sufficient evidence to compare performance across the three types of NBS with added structure (artificial, hybrid, natural), as well as restoration interventions.
- Filling the evidence gaps related to NBS performance for socioeocomic outcomes and/or in understudied ecosystems such as kelp, coral and seagrass.