This collaborative research effort amongst multiple institutions addressed the interplay between natural and societal dynamics of estuarine shorescapes. Worldwide, the integrity of salt marsh ecosystems and the ecosystem services they provide to coastal communities has been compromised by shoreline hardening with structures like bulkheads, riprap revetment and seawalls to protect against property erosion.  With rising seas and coastal development intensification, property owners will likely demand more shoreline protection. Natural and nature-based shoreline protection approaches ? for our purposes, living shorelines ? are encouraged through various government policies as alternatives to armoring for several reasons.  In addition to providing erosion control and storm protection, they, unlike structures such as bulkheads, can adapt to rising seas.  They also provide numerous additional societal and ecosystem benefits, including carbon sequestration, water quality improvement, and critical habitat for fish, shellfish, and wildlife. Nature-based approaches include both conserving and restoring tidal marshes. Because much of the US coastline is privately owned, marsh sustainability along coasts and estuaries, such as Chesapeake Bay, will be greatly influenced by individual property owner decisions.

This  research examined the interplay between humans and nature that contribute to decision-making regarding whether a shoreline may be armored, restored with a living shoreline, or left unchanged?decisions that collectively dictate marsh ecosystem sustainability. Our investigation began with an assessment of the current trajectory of Virginia tidal marshes under sea level rise with the existing land use practices. Absent aggressive management interventions to maintain and enhance marsh resources in the landscape, we project Virginia will lose a significant proportion of current marshes in the coming decades.

Living shorelines may offset lost marsh ecosystem services if the created marshes provide equivalent services and can persist under rising seas.  A multi-year field evaluation of ecosystem function equivalency between living shorelines (created marsh with stone sill) and natural fringing marshes found that living shorelines could successfully sustain or create a suite of ecosystem services similar to natural marshes in both urban and rural settings.  

While implementation of living shorelines has increased over the past decade, armoring is still the most common choice of property owners. Multiple investigations into the decision-making processes that generate shoreline management actions found that individual shoreline property owners are the key determinant of outcomes. Their shoreline modification decisions (armor, living shoreline, do nothing) were primarily driven by their perceptions of risk, cost, and their social network interactions with marine contractors, neighbors, and non-profit organizations. An enhanced recognition of the value of outreach education for contractors and the role of nonprofit organizations in encouraging living shorelines were key takeaways.  Another was the challenge of effectively translating clear policy preferences for living shorelines through the regulatory network to property owners.

Investigation of policies and regulatory approaches from Delaware to Florida found those same needs and challenges everywhere.  Regulatory practices simply do not effectively encourage use of living shorelines. In addition, the common use of fixed jurisdictional boundaries for estuarine marshes exacerbates the difficulty of managing shoreline natural resources because the jurisdictional boundaries do not respond to changing shoreline conditions. 

Examination of possible Chesapeake Bay shoreline futures assuming increased property owner preferences for living shorelines indicates the current implementation rate of management actions is insufficient to meaningfully offset anticipated loss of marsh ecosystem services due to sea level rise, even if all actions were to install living shorelines where suitable.  To achieve sustainable marsh ecosystems, the scope and rate of marsh protection and restoration must dramatically increase. Stronger regulatory action combined with aggressive land use management is required to create the possibility for sustained marsh presence in the landscape.  The investigation also identified opportunities to enhance property owner preference for nature-based approaches by fully valuing benefits derived from marshes (e.g., carbon sequestration, water quality improvement, flood reduction), thus creating robust economic incentives for living shoreline implementation. If regulations and incentives resulted in increased and widespread use of living shorelines and land management policies preserved marsh migration opportunities, outcomes for marsh ecosystem services could be substantially improved.

This project directly addressed the current societal need to develop evidence-based policies and plans to preserve valuable marsh ecosystem services and enhance community resilience. To apply project findings, project team members have fostered strong networks of diverse stakeholders with a role in shoreline management, including local officials, state legislators, public interest groups, and property owners. Data developed for this project and analyses of natural system trajectories in the study area have been used to inform both policy development and management strategies for Virginia, specifically in regard to the climate change resilience planning in the coastal zone. This project provided invaluable transdisciplinary learning opportunities for multiple undergraduate, graduate, and law students, as well as early career scientists, to help prepare and encourage them to be future leaders who will holistically address the pressing and complex social and environmental issues arising from climate change.

Last Modified: 12/27/2021
Modified by: Randolph M Chambers