Knowledge Gaps and Research Priorities in Living Shorelines Science: Insights from Stakeholder Interviews Throughout the U.S. Pacific Coast

Living shorelines restoration is an increasingly important method of enhancing coastal resilience in the face of changing climate and rising sea levels, as it provides nature-based alternatives to shoreline armoring while maintaining biodiversity (Bilkovic et al. 2016; Gittman et al. 2016b; Smith et al. 2020). Coastal restoration using natural infrastructure furthermore presents opportunities for community engagement and collaboration among diverse groups of stakeholders (Bragg et al. 2021; Molino et al. 2020; Smith et al. 2020). These benefits to local ecosystems and communities demonstrate the value of utilizing living shorelines for coastal resilience on a larger scale. In order to broaden the use of living shorelines, however, several limitations to their widescale implementation must first be addressed.

First, a consistent definition of living shorelines is lacking; many types of coastal habitat restoration in different geographic locations are encompassed by the term “living shorelines” (Moosavi 2017; O'Donnell 2017; Smith et al. 2020). Furthermore, living shorelines are highly context-dependent, and extending their use to new coastal communities requires careful consideration of regional needs and management concerns. Compilations of case studies varying by landscape setting, energy level, and habitat type are a work in progress, but a more concentrated effort in developing these resources is needed (Beagle et al. 2019; SCC et al. 2010; Judge et al. 2017). The concept of using living shorelines is still relatively new, particularly on the Pacific coast of the United States (Bilkovic et al. 2016; Boudreau et al. 2018; Smith et al. 2020). Restoration designs on the U.S. west coast therefore often draw from East coast case studies and need to be adapted to Pacific shorelines, which are characterized by more open coast area and shoreline hardening (Boudreau et al. 2018; Gittman et al. 2015; Hanak and Moreno 2012). Demonstration projects testing new techniques and evaluating the likelihood of their success, especially along the Pacific coast, are limited (SCC et al. 2010; Russell and Griggs 2012; Saleh and Weinstein 2016). A central goal of our research was to investigate regional differences among approaches to living shorelines, highlighting projects on the Pacific coast through stakeholder interviews to gain a better understanding of the challenges specific to this region.

One particular area that merits attention is discussion with stakeholders about successes, perceptions, and limitations to implementing living shorelines restorations. Several studies have compiled information on different restoration methodologies through discussion with experts and literature review to identify restoration goals and guidelines (Baggett et al. 2015; Fitzsimons et al. 2020; O'Donnell 2017; Smith et al. 2020; Ridlon et al. 2021; Waltham et al. 2021; Zeigler et al. 2021). These studies have highlighted the need for greater discussion and data sharing among coastal restoration practitioners. Some research furthermore included a practitioner interview or survey component (Fitzsimons et al. 2020; Molino et al. 2020; Smith et al. 2020); however, direct interviews with interdisciplinary stakeholders have a very limited representation in living shorelines literature. Through both a literature review and interviews with coastal restoration practitioners from a variety of disciplines and communities, we identify scientific knowledge gaps, priorities for future research and opportunities for community engagement.

The first component of our study consisted of a review of relevant literature encompassing diverse perspectives in living shorelines science. The databases Academic Search Complete, ScienceDirect, Web of Science, and JSTOR were used in addition to Google Scholar to find peer-reviewed research articles on living shorelines science, from foundational discussions to recent studies incorporating novel methodologies. Several search terms were used to find literature, given the inconsistencies in living shorelines definitions and the variety of methods used by practitioners. “Living Shorelines,” “Nature-Based Infrastructure,” “Nature-Based Engineering,” “Coastal Resilience,” “Shoreline Hardening,” “Coastal Restoration,” “Coastal Management,” “Oyster Seagrass Restoration,” and “Multi-Habitat Coastal Restoration” were all searched in each database to find relevant literature, with secondary terms added including “stakeholders,” “interviews,” “practitioners,” “community,” and “community engagement.” In addition to the journal articles resulting from these searches, we furthermore reviewed publications from nonprofit organizations (e.g., The Nature Conservancy), state and local government agencies (e.g., the California State Coastal Conservancy), white papers, proceedings from academic society and local government meetings, and mission statements from funding organizations.

The second component of this study consisted of direct interviews with stakeholders involved in living shorelines restoration efforts, also referred to in this study as practitioners to reflect their active involvement with restoration projects. These living shorelines practitioners were selected with the goal of equally representing different disciplines and organization types along the Pacific coast. Some interviewees based in the East and Gulf coasts were included due to their familiarity with projects in the Pacific, or their specialized knowledge of techniques that could be applied to Pacific coast systems in the future. A list of potential contacts was created throughout the literature review process and was expanded through input solicited from several experts in the field of coastal restoration. Interviewees were selected from nonprofit and grassroots organizations, state and federal agencies, academia, consulting and engineering firms, and funding groups. Biologists, ecologists, oceanographers, engineers, policy specialists, and stakeholder engagement professionals all participated in interviews. Please refer to Table 1 for an overview of the organization types and disciplines represented among interviewees, in addition to their geographic distribution.

Interviewees took part in a phone or video call ranging from 25 mins to 1.5 hrs in length to discuss challenges and opportunities in living shorelines science. The following questions were asked to each practitioner:

1. What have you found to be the biggest challenges or barriers in advancing living shorelines research in your work?

2. What projects and programs do you think are most needed to help advance living shorelines and on-the-ground climate resilience measures?

3. What research topics or innovative restoration methodologies would you be interested in learning more about, both in your community and in other regions? Are there specific novel techniques for increasing coastal climate resilience that you think need more support or attention?

4. What are the needs to help enhance scalability of living shorelines projects beyond individual locations?

5. How is your living shorelines research being used by practitioners and communicated to the public, and how might this be improved upon?

6. Are you seeking any new partnerships or methods of community engagement that would be particularly valuable in accomplishing your project goals?

7. How can communication around advancements in living shorelines science and solutions be enhanced within the scientific community?

A total of 23 living shorelines practitioners participated in interviews between March and June 2020. While 34 practitioners were identified and contacted for interviews based on our literature review and additional input from experts, the 23 interviewees described here represent the subset of practitioners contacted who were responsive to our request and able to participate. Interviews were conducted between March and June 2020. After interviews were completed, individual responses to interview questions were reviewed and common themes were identified. The major challenges and opportunities discussed by practitioners were then compared to those documented in the literature.

Our literature review included a total of 50 sources, incorporating perspectives on living shorelines projects from the East, West, and Gulf coasts of the U.S. (Fig. 1). The sources reviewed included journal articles on small-scale living shorelines projects monitored primarily by academic researchers, as well as case study compilations for larger collaborative efforts between nonprofits and agencies at the State or Federal level. Pacific coast studies were more limited in scope; of the 50 sources reviewed, only 18 (36%) were specific to the Pacific coast. Among Pacific coast studies, projects were clustered in areas with low-energy back bays, including San Francisco Bay and Elkhorn Slough in northern California; Newport Bay and San Diego in southern California; and Puget Sound in Washington State. The geographic distribution of sources highlighted the relative lack of literature and case studies from West coast systems, a result of living restoration techniques being relatively newer to this region. Comparing sources from both regions allowed us to distinguish knowledge gaps unique to the Pacific coast from those that are overarching needs in living shorelines science.

The literature review identified a variety of challenges in living shorelines science, which are summarized in Table 2 and compared with practitioner-identified challenges. First, there is a critical need for quantitative assessments of long-term structural integrity of living shorelines, as well as research into their maintenance requirements and success in adapting to rising sea levels. Another widely cited knowledge gap is a lack of projects directly comparing the effects of “green” or natural versus “gray” or artificial structures. The incorporation of any artificial element into a living shorelines design is controversial among living shorelines practitioners (Boudreau et al. 2018; Moosavi 2017). While some advocates of hybrid green-gray approaches are encouraged by the durability of artificial elements in the face of high wave energy, many biologists are concerned that small-scale habitat restoration adjacent to armoring will add little ecological value and do nothing to address the problem of hardened shorelines.¹ Living shorelines themselves, when in the proper coastal setting, have been documented to be more effective in reducing the impacts of storms than armored structures (Bilkovic et al. 2016). However, in open coast, high energy environments, success is limited (Walker et al. 2011). More research into these high-energy coastal contexts, especially during extreme weather events, is needed (Gittman et al. 2015; Hanak and Moreno 2012; Saleh and Weinstein 2016). Detailed risk assessments and hazard modeling are imperative in understanding the durability of living shorelines into the future and assessing the role they will play in reducing flood risk (Aerts et al. 2018; Reguero et al. 2018; Russell and Griggs 2012).

Long-term monitoring of ecosystem services has been highlighted by numerous sources as another essential component to living shorelines success, especially regarding wave attenuation, faunal community response, and carbon sequestration (Benayas et al. 2009; Bilkovic et al. 2016; Davis et al. 2015; Gittman et al. 2016a; Patrick et al. 2016; Simenstad et al. 2006; Zeigler et al. 2018, Ridlon et al. 2021). These long-term data convey the success or failure of nature-based infrastructure at meeting its coastal resilience goals, and are needed to assure coastal property managers, landowners, and policymakers that their investment in natural alternatives to shoreline armoring is worthwhile (Baptist et al. 2019; Sutton-Grier et al. 2018). Next steps include streamlining communication between science and management and improving public perception of living shorelines (Bragg et al. 2021; Currin 2019; Smith et al. 2020; Waltham et al. 2021)². Clearer communication of living shoreline benefits to the public using specific examples will establish ground-up demand and lead to the institutional capacity building required for larger-scale implementation.³ In short, a number of logistical and sociological hurdles underlie the major knowledge gaps in living shorelines research, indicating areas where support is most needed.

Many of the major challenges and barriers to living shorelines advancement identified in the literature review corresponded with the findings of the interviews (Table 2). Practitioner responses to interview questions varied to some extent by discipline, but many responses were common or interconnected among interviewees. Fig. 1 indicates the geographical range of interview participants; most practitioners were from northern or southern California (Table 1), reflecting the clustered distribution of living shorelines projects observed in the literature review. The majority of interviewees and research articles consulted both indicated that one of the most pressing challenges is a lack of long-term data evaluating how living shorelines projects are meeting their specific goals, particularly along the Pacific coast given that living shorelines have historically been concentrated in East coast systems. Living shorelines projects are often monitored for a few years past their implementation, generally up to about five years with few exceptions. There is a simultaneous need for more demonstration projects to begin and for monitoring of existing projects to continue, a need that has been consistently identified over the past decades and prompted many suggestions from interviewees. West coast living shorelines studies require further research into project lifespan, standardized timelines and monitoring methods, and effective restoration materials in different coastal settings. A growing network of professionals and a collaborative effort to share data and methods is needed to guide future research and streamline restoration processes in the future. As is further described in the discussion, interviewees identified several approaches to increase community investment in restoration projects for long-term persistence and positive perceptions of new projects.

Interviewees across multiple disciplines and organization types identified a great need for capacity building when it comes to living shorelines restoration, especially professional training programs. Many practitioners mentioned a lack of engineers trained in nature-based infrastructure and familiar with its unique benefits and challenges, a limitation also identified various times within the literature review. For living shorelines to become a more widely used engineering practice, long-term studies of durability, adaptation, and maintenance needs are also essential, especially in high-energy environments. Specific regional design guidelines should be created to distinguish which techniques have succeeded and failed in a given coastal setting. These specifications can inform training and information sessions for interested practitioners and can refine the method selection process when designing future projects.

Improved communication with regulatory agencies was also identified by multiple practitioners and various literature sources as an area where further work is greatly needed. Policymakers rely on concrete evidence that living shorelines work as intended, and this is not achievable without ample scientific support and effective communication. Maintaining dialogue between science and management will improve regulatory agencies' understanding of living shorelines projects as well as researchers' understanding of permitting requirements. Streamlining the permitting process for future projects will enable new living shorelines projects to get off the ground more efficiently and will make them an accessible strategy for more communities and small nonprofits. Finally, increased community engagement and data sharing is needed to shift public perceptions of living shorelines and promote the concept of natural beaches and their benefits.

To address the challenges listed above, interviewees proposed a wide range of solutions from innovative restoration studies to educational programs and communications campaigns. The most commonly mentioned approaches are outlined in Table 3, as well as the prevalence of these approaches in living shorelines literature. The discussion and recommendation section overviews many of the most commonly referenced suggestions for specific project types, but several one-off suggestions are listed in Table 3 as well. Some of these include unconfined sediment placement from dredge material as a method of sea level rise mitigation, analysis of nature-based infrastructure in groundwater studies, where adaptability is a clear advantage over armoring, and research into natural irrigation techniques for restoration projects during drought periods. Other suggestions were specific to oyster restoration, including the development and use of natural reef balls, the implementation of shell recycling programs and networks, and the creation of higher-relief oyster beds for greater structural stability. Finally, increasing the accommodation space between coastlines and hardened structures to accommodate wave action was identified specifically in one interview as a valuable research area, though this echoed the needs outlined by many interviewees.

Both the literature review and stakeholder interview components of this study provided insight into current limitations in living shorelines science, as well as priority areas for future research. Interviewees suggested a variety of strategies, projects, and programs needed to address these challenges. They further identified areas where available funding can be effectively placed to create a scalable impact. These recommendations built upon many of the conclusions outlined within living shorelines literature and centered on the five following topics: supporting innovative demonstration projects, supporting engineer trainings and needs, funding long-term monitoring, investing in communications and media projects, and prioritizing community engagement. The focus areas identified through this analysis provide a guide for future restoration and funding efforts.

Supporting Demonstration Projects with Innovative Methods.—Supporting pilot projects in their early research and development stages was one of the most frequently suggested ways to make a scalable impact in living shorelines research. Lack of funding for initial implementation of new adaptation strategies remains a major barrier, especially in Northern and Central California (Moser et al. 2018). By funding preliminary research in its academic and/or early planning stages, strategically placed funding and community engagement can help demonstration projects get off the ground. With effective communication and documentation throughout the project, this initial support can then be used to leverage public funds on a larger scale (e.g., grants from state and federal agencies) (Fitzsimons et al. 2020). Furthermore, to encourage restoration efforts on privately owned lands, economic incentives should be promoted and publicized to attract the attention of private landowners who may otherwise not have interest in, or knowledge of, implementing a living shoreline on their property (Scyphers et al. 2020). The next few paragraphs detail several research areas that should be a priority in coastal restoration based on their innovative methodologies.

First, projects involving risk assessment and evaluating the potential for managed retreat are greatly needed. Many practitioners reiterated the challenge of a highly urbanized and developed Pacific coastline, especially in southern California, which requires restoration approaches that cannot be applied directly from case studies in other regions. Adding habitat value to these hardened coastlines is crucial, as is planning for managed retreat in the face of sea level rise. Interviewees consistently identified risk assessments as a way to increase scalability of living shorelines. Sea level rise modeling and incorporating extreme weather events will inform next steps, including site selection for future pilot projects. It will also aid in identifying “future habitat” where coastal habitat restoration efforts should be focused to transition to higher sea levels; this can range from efforts to convert agricultural land that will be unusable in the future or removing infrastructure currently in place that will not withstand sea level rise. These risk assessments will further aid in developing estimates of cost and shoreline protection value, a key piece of information for policymakers (SCC et al. 2010; Reguero et al. 2018).

Research assessing living shoreline success in high-energy environments is also needed to inform management strategies, specifically restoration site selection, project design, and expectations for structural persistence and maintenance. Living shorelines have generally been limited to low-energy areas such as back bays in order to introduce nature-based infrastructure in areas with greatest potential for success. The focus must now be extended to regions where wave energy and erosion are high, in order to further demonstrate their efficacy to engineers, policymakers, and other stakeholders involved in coastal management. In these high-energy areas, several methodologies must be considered and directly compared. This is especially true in systems where “gray” infrastructure is more commonly used, readily available, or easy to implement. Considering the use of hybrid “green-gray” structures may be a valuable first step in increasing resilience within highly urbanized communities, while simultaneously increasing visibility of and engagement with living shorelines (Moosavi 2017; Silvertooth et al. 2019). For example, revegetation efforts along a horizontal levee or habitat restoration adjacent to a seawall already in place will increase ecosystem services and present a first step in using natural structures as an alternative or draw attention to removing the armoring itself. Similarly, using a breakwall in conjunction with oyster restoration was found to enhance ecosystem recovery in a high-energy environment in Florida (Safak et al. 2020). These approaches must be considered very carefully, given that many researchers are well aware of the scant ecological value of projects closer to the “gray” end of the spectrum and caution that the habitat restoration is more of a disguise for armoring than an adaptive approach to coastal resilience (Smith et al. 2020)¹.

To better inform engineers, policymakers, and other stakeholders involved in coastal management, studies directly assessing benefits and drawbacks of green versus gray structures in different Pacific coast systems would be highly useful. Beyond establishing pilot projects and monitoring their success, a coordinated effort is needed across the Pacific coast to test green infrastructure in a series of high-energy coastal environments. This type of regional study would provide replicated data to engineers, geomorphologists, and policymakers that can inform which conditions are ideal for fully natural solutions such as dunes and, on the other hand, which conditions may require an understory of rock. It would furthermore help identify instances in which using durable hybrid elements as one component of a living shoreline might offer a better, or transitional solution. For example, Baycrete/ECOncrete (concrete mixed with natural materials such as shell or sand) may present an opportunity to construct high-relief oyster beds, considering the limited bed size of the native Olympia oyster. Projects that entail standardized monitoring metrics over an extended period (10+ years) and clearly communicate their results to scientists across the Pacific coast are a funding priority based on the findings of our interviews and literature review.

In addition to advocating for studies in high-energy environments, many practitioners and particularly engineers expressed that research on the open Pacific coast provides further opportunities for innovation. Most interviewees with this suggestion worked at the interface of science and management at relatively large scales, indicating that these projects are especially important next steps in the big picture of advancing coastal resilience. Some specific examples include restoration of offshore vegetation, including kelp and eelgrass; studying their impacts on sedimentation patterns and wave attenuation will become increasingly important with sea level rise and shoreward migration. Projects linking increased numbers of habitat types from upland to offshore should also be given priority, as they will provide a higher degree of structural diversity, thereby increasing habitat value and wave attenuation (Zeigler et al. 2018). These types of open coast studies are also important in better understanding engineering needs in higher-energy environments (Walker et al. 2011).⁴ Compiling a coordinated set of data to inform the restoration technique selection under a given set of physical and biological conditions should be a priority to fill this knowledge gap and provide resources for future practitioners.

Finally, demonstration projects with an experimental design, especially a randomized replicated design, are needed to reinforce scientific support behind living shorelines projects (Gellie et al. 2018). Replication along the Pacific coast will establish the settings in which different approaches are most effective as well as their projected likelihood of success. Data sharing among these projects and dialogue between the communities in which they take place should be facilitated. The results of these studies can be combined to contribute to a regional guide outlining different techniques and the best contexts in which to use them.

Supporting Engineer Trainings and Needs.—The low number of engineers working on living shorelines projects was identified in the literature review as a common challenge for restoration efforts across the U.S. (identified in 36% of sources reviewed; see Table 2). A need for more engineer involvement on Pacific coast projects in particular was emphasized by a majority of practitioners interviewed (57%; Table 2). In the context of the interviews, the definition of engineers included geomorphologists with expertise in the structural dynamics of coastal ecosystems, geologists studying shoreline processes, and GIS practitioners assessing structural changes over time. To increase engineer interest and involvement in living shorelines projects, more certified training programs in natural infrastructure are needed as well as targeted recruitment efforts through university interest groups, seminars, and collaboration with interdisciplinary professional societies. One program that may present an opportunity for collaboration is the Engineering with Nature® (EWN) program developed by the U.S. Army Corps of Engineers (USACE; Kurth et al. 2020). EWN has partnered with nonprofits such as The Nature Conservancy and its Natural Infrastructure Initiative, providing a model upon which recruitment and partnership efforts could be based. These partnerships also provide a unique opportunity for future collaboration on living shorelines projects; restoration practitioners can benefit from engineers' perspectives, and direct work with the USACE can help to streamline permitting and foster connections between coastal managers and engineering firms. Communications projects drawing attention to and building upon these existing resources could go a long way in generating interest and expanding training programs.

Two concerns raised in interviews with both engineers and policymakers were related to structural persistence of non-hardened structures and the efficacy of small-scale projects in achieving the desired restoration goals. Overall, these practitioners expressed a need for research that can provide data showing that nature-based approaches are both practical and feasible. First, engineers identified a need for projects documenting the ability of non-hardened structures to effectively persist over time and stabilize coasts, such as oyster restoration projects as a substitute for seawalls, or dune restoration using driftwood and cobble. Another area of interest among engineers interviewed was the influence of grain size on dune stability and vegetation growth and faunal communities. Second, both engineers and policymakers acknowledged that smaller-scale projects are considered valuable within their field, but only so as they lead to larger-scale projects that increased the area of restoration. This perception may overlook the importance of these pilot projects for demonstrating efficacy and usefulness of nature-based infrastructure. Finally, a major knowledge gap emphasized in both literature and stakeholder interviews was a lack of direct green vs. gray comparisons. In Kurth et al. (2020), scientists recommended conducting formal tradeoff analyses comparing shoreline armoring with natural infrastructure; this was supported by several other sources indicating a need for longer-term data on stability, cost, and maintenance over time for both hard and soft defenses from sea level rise (Bragg et al. 2021; O'Shaughnessy et al. 2020; Sutton-Grier et al. 2018)⁵. Targeting these questions and research gaps can answer important questions within the field of natural resources engineering and establish guidelines for long-term design.

Continuing to Fund Long-Term Monitoring.—The most frequently identified need among all practitioners interviewed (57%) and supported strongly by literature sources (62%; Table 2) was increased funding for long-term monitoring especially for Pacific coast projects. Datasets of 10+ years are integral to understanding living shorelines' success from cross-disciplinary perspectives (Bayraktarov et al. 2016; Waltham et al. 2021). The primary goal of engineers is to create long-lasting structures, and insufficient data on persistence of living shorelines is a barrier in recruiting engineers to work with nature-based infrastructure. From a biological standpoint, ecological communities fluctuate both seasonally and annually, and long-term monitoring data is needed to distinguish restoration effects from interannual variation. Maintenance requirements and costs over time are also important information for property owners, local governments, and potential mitigation funders, and cannot be properly assessed without long-term studies. Given this need for long-term data and the research priorities identified in our study, priority should be given to projects assessing the structural persistence of nature-based infrastructure, with a standardized set of metrics such as elevation, habitat cover, ecological community responses, and maintenance requirements. Potential funders should seek out restoration efforts with concrete communications goals or with coordinated projects in other geographic locations.

Small foundations are integral to funding monitoring programs, especially in partnership with universities and local nonprofits. Having a long-term dataset was often referenced by practitioners when discussing scalability, as it provides more concrete evidence of the efficacy of living shorelines to planners and managers. Providing funding for unique monitoring approaches (i.e., community science programs, volunteer data collection days, video and drone monitoring) would be a creative strategy to increase visibility of living shorelines projects and to incorporate community engagement. Because long-term monitoring requires continual efforts to secure funding, leveraging funds in this way is a strategic approach that will contribute to larger-scale research and secure support for smaller organizations that may not have time or capacity to continually apply for short-term funding.

Investing in Communications & Media Projects.—Communications campaigns were also recommended by a majority of interviewees (12 practitioners or 52%: Table 2). This need was identified in the literature review as well, within 14 sources or 28% of the literature reviewed (Table 2). The strong relative emphasis on communications campaigns in interviews highlights a need that may be underrepresented in published literature. While interviewees indicated that communication is progressing among scientists studying different habitats (dunes and oyster beds, for example) and between scientists and other professionals, improvement is still needed. Improved communication begins with better consensus on the definition of living shorelines themselves. The interdisciplinary nature of living shorelines work often means that different experts have different interpretations of which projects can be considered living shorelines. Scientists need to continue building a network to compile case studies regionally and to be aware of advances in disciplines not directly related to their own. The ability to compare methodologies, materials, coastal context, and successes or failures is needed for all types of living shorelines restoration (Baggett et al. 2015; Bayraktarov et al. 2016; Molino et al. 2020; Zeigler et al. 2021). Better communication is also especially needed in conveying the importance of living shorelines to the public (Bragg et al. 2021; Molino et al. 2020).

The ability of coastal communities to visualize proposed changes to their local beaches and properties is essential in gaining public support, whether it be through a projected image presented at a local meeting, a video project or virtual reality experience, or an example of a successful pilot project in a similar coastal context. Several practitioners suggested unique approaches to providing visualization for proposed or ongoing projects. Social media outreach is an important first step, and regularly providing educational information and project updates will shift public knowledge and perceptions. Other creative approaches to outreach include showing drone imagery of restored sites, models of proposed projects, or simulations of proposed changes on a phone app. These are all engaging examples of showing local communities, policymakers, and landowners how their local coastline will change and highlighting benefits of natural shorelines.

Communicating benefits to local management and communities is an important step in gathering more ground-up demand for living shorelines projects, and communications campaigns are particularly effective if economic incentives are highlighted. While the ecological value and ecosystem services of living shoreline restoration are important, it is essential to communicate the precise value of increased fish production, water quality improvements, wave attenuation, and other benefits. Projects translating ecosystem services into economic values, with specific plans for communicating these findings, should be considered for funding as they will drive increased demand and leverage future funds.

Prioritizing Community Engagement.—Practitioners agreed that community engagement is essential for living shorelines success and should continue to be a major focus in future restoration efforts. Increasing connection with local stakeholders, providing an outlet for them to express their concerns, keeping them informed about recent scientific findings, and demonstrating the services provided by restored habitats are all necessary steps in maintaining this connection. Community engagement has been identified to both increase stewardship of existing and restored habitats as well as to increase understanding and support for restoration and associated funding (Bragg et al. 2021; Chang et al. 2019; Scyphers et al. 2020)². Efforts to promote volunteer-based or community science also provide an opportunity for long-term data collection and increase engagement with restoration projects; such stakeholder engagement efforts have been shown to change the perceptions and views of community members regarding restoration projects (Boudreau et al. 2018; Josephs and Humphries 2018).

An increased focus on nature-based coastal resilience measures is especially needed in communities affected disproportionately by sea level rise and environmental degradation. In under-served communities, socioeconomic factors often limit access to environmental education and to nature itself. Public perception and community well-being can both be supported through educational measures, such as field trips to restored beaches for students or discussions with local fishermen about increased fish presence post-restoration. Agencies such as the California State Coastal Conservancy (SCC) have been working in recent years to re-center their mission on environmental justice and equity; these efforts are needed in all regions to increase scalability of public interest and collaboration.⁶ Building ground-up demand for living shorelines projects starts with building a connection to projects within communities, then enhancing dialogue between communities.

Fostering connections between communities and government in joint projects can have lasting positive impacts, especially when local knowledge enhances resource management. This can be seen in the collaboration between indigenous communities and local government in community-based subsistence areas and biocultural resource management in Hawaii (Chang et al. 2019; Winter et al. 2018). Indigenous fish ponds in Hawaii serve as a valuable example of community-based adaptive management and cross-disciplinary collaboration. They highlight the importance of supporting indigenous group autonomy and enhancing productive relationships between stakeholders within a community.

Lessons Learned for Future Efforts.—Both the literature review and interview portions of this study reaffirmed a need for continued outreach and discussion with stakeholders in living shorelines restoration, including local community members and volunteers, homeowners, students, scientists, engineers, members of state agencies and nonprofit organizations, and more. Engaging with stakeholders, including coastal landowners and other community members, early in the restoration process allows for priorities and community values to be established early on and persist throughout all project stages (Fitzsimons et al. 2020; Josephs and Humphries 2018). Taking advantage of every opportunity possible in bringing people together and enhancing dialogue between communities, from meetings and webinars to accessible regional conferences, is essential (Bragg et al. 2021; Toft et al. 2017). Many interviewees were very enthusiastic about continuing stakeholder outreach efforts, emphasizing the importance of diverse perspectives in discovering opportunities in coastal communities. Increased representation is particularly needed moving forward for native communities and communities of color. These groups should form a substantial part of discussions on living shorelines, as their involvement is needed to address their concerns and promote projects that advance their interests and well-being.

Our research and conversations also highlighted a need for increased communication and data sharing among West coast living shorelines practitioners. Our interviews primarily incorporated perspectives from the Pacific coast; many interviewees from this region agreed that local restorations are heavily informed by work done in the Gulf and East coasts, where living shorelines research, especially involving oyster restoration, is older. Less is still known about restoring certain Pacific coast species such as the Olympia oyster, or addressing challenges within unique coastal settings (i.e., open coast, higher energy environments). Supporting demonstration projects on the Pacific coast in new coastal contexts, collecting long-term data, and sharing findings effectively among stakeholders are all essential next steps in increasing the scale of living shorelines restoration in the future.

After reviewing recent literature on living shorelines and gathering insight from a varied group of cross-disciplinary practitioners, the following priorities were identified: (1) supporting pilot or demonstration projects in their early research stages, (2) increasing availability of training programs for engineers utilizing nature-based infrastructure, (3) monitoring ecological and structural properties of living shorelines in the long-term (5+ years), (4) communicating results, project significance, and visual resources to stakeholders within and between communities, and (5) advancing the causes of environmental justice and equity.

This work was supported by funding from the Honda Marine Science Foundation, which has since been absorbed by the American Honda Foundation. We would like to give special thanks to the Honda Marine Science Foundation board members Raminta Jautokas, Jessalyn Ishigo, and advisors Sarah Sikich and Chris Yates for their substantial input throughout all stages of this research. This would not have been possible without the interest and support of all stakeholders interviewed in this study, and we thank them for their time and insightful discussions.