Study Notes on Coastal Wetlands and Living Shorelines Valuation

Valuing Present and Future Benefits of Coastal Wetlands and Living Shorelines
Authors and Affiliations

  • Authors: Donna Marie Bilkovic, Andrew M. Scheld, Robert Isdell, Pamela Mason, Sarah Stafford, Molly Mitchell, Cirse Gonzalez-Dorantes, Randolph Chambers, Matthias Leu, Susanna Musick, Sean Gregory, Jessica Hendricks, Oluwakemi Dada, Gabriel Benson

  • Affiliations:

    • Virginia Institute of Marine Science, William & Mary, Gloucester Point, VA 23062, USA

    • William & Mary, Williamsburg, VA, USA

    • Chesapeake Bay National Estuarine Research Reserve in Virginia, Virginia Institute of Marine Science, Gloucester Point, VA 23062, USA

Keywords

  • Economic valuation

  • Natural capital

  • Marsh

  • Nature-based coastal protection

  • Ecosystem services

Abstract

  • Marshes serve as critical natural capital assets for coastal communities, playing an essential role in maintaining ecological balance and providing multiple benefits to humanity. They offer numerous ecosystem services such as coastal protection against storms and flooding, nutrient removal from water bodies, habitat provision for diverse flora and fauna, and recreational opportunities for communities.

  • This study thoroughly investigates the present and future distribution of tidal marsh ecosystem services in Virginia, employing an interdisciplinary mixed-methods approach and spatially explicit valuation techniques to analyze economic impacts. A benefit transfer analysis was conducted which utilized literature-derived values customized for specific site conditions. Stated preference surveys were designed to target recreational users, shoreline management decision-makers, and local communities to capture a holistic view of ecosystem service valuation.

  • The results reveal that the total economic value of marsh services is substantial, approximating $90 million annually, which translates to about 3.3% of the annual GDP for the region, indicating the significant economic reliance of local communities on these ecosystems. The study also forecasts slight projections of service value increases due to anticipated marsh migration and implementation of living shoreline strategies designed to enhance resilience against climate change.

  • Notable variability in service values based on local context reinforces the importance of tailored shoreline management decisions to bolster local economies and biodiversity conservation initiatives.

1. Introduction

  • Coastal environments are increasingly vulnerable to climate change, facing challenges such as habitat loss, property damage, and declining natural resource availability. These threats undermine the unique ecological functions that coastal wetlands provide, leading to significant economic and social costs.

  • Traditional shoreline hardening practices, like seawalls, often result in habitat loss, reduce biodiversity, and compromise the resilience of coastal ecosystems against extreme weather events. Moreover, the progressive degradation of coastal wetlands threatens their ability to deliver critical ecosystem services that are vital for human well-being.

    • Ecosystem Services (ES): Defined as the ecological characteristics, functions, or processes contributing to human well-being. Key roles of coastal wetlands encompass:

      • Provision of raw materials and food supply to local fishing communities

      • Coastal protection against storm surges and erosion

      • Erosion control to prevent property and habitat loss

      • Water purification, safeguarding public health and aquatic life

      • Maintenance of fisheries, which are crucial for food security and local economies

      • Carbon storage, playing a role in mitigating climate change

      • Recreational, tourism, and educational opportunities, enhancing quality of life and promoting environmental awareness

  • Coastal wetlands help mitigate the impacts of climate change through mechanisms such as:

    • Wave attenuation, which reduces the power of storm waves hitting shorelines

    • Erosion reduction through sediment stabilization

    • Adaptive strategies to increase resilience to sea-level rise

    • For instance, during Hurricane Sandy, wetlands effectively minimized annual flood losses by 16%, resulting in savings of $625 million in damage costs.

  • Protecting and restoring wetlands enhances vital processes like nitrogen removal and carbon sequestration, with efficiency rates in mangroves and tidal marshes exceeding that of tropical forests, emphasizing their importance in combating climate change.

  • Innovative nature-based coastal protection strategies focusing on the creation and restoration of vegetated wetland habitats, termed living shorelines, improve ecological functions while enhancing community resilience. Living shorelines are recognized for their capacity to maintain essential ecosystem processes, in contrast to traditional armoring methods that typically offer minimal ecological value.

  • Current research highlights the urgent need for increased understanding of ecosystem services to allocate limited conservation and restoration resources effectively.

1.1 Ecosystem Services Valuation

  • The average monetary value of coastal wetlands has been estimated at $193,845/ha/year (2007 US$), reflecting considerable variability between $300/ha/year and $887,828/ha/year, underscoring the diversity of conditions across different regions and types of wetlands.

  • The importance of quantifying and understanding these metrics is underscored, as many derived values come from a limited number of studies, necessitating further research.

2. Methods

2.1 Study Area

  • The study area focused on the Middle Peninsula, positioned on the western shore of the Chesapeake Bay, comprising six counties (Essex, Gloucester, King and Queen, King William, Mathews, and Middlesex) with an approximate population of 90,000 spread across 3,592 square kilometers.

  • Dominant industries in the region encompass agriculture, forestry, commercial fisheries, aquaculture, and tourism, all of which are significantly influenced by the health of coastal ecosystems.

  • In 2022, NOAA designated the Middle Peninsula as one of the ten “Habitat Focus Areas” (HFAs) to maximize restoration impact and bolster coastal community resilience against climate change.

2.2 Ecosystem Service Valuation Process

  • The ecosystem services valued in this study are:

    • Carbon sequestration, contributing to climate change mitigation

    • Nutrient removal, essential for water quality management

    • Fish habitat provision, supporting local fisheries

    • Storm risk reduction, crucial for protecting infrastructure and communities

    • Recreational opportunities, such as birdwatching, fishing, and boating, enhancing local tourism

  • Benefit Transfer: This process applies economic value estimates derived from past studies to evaluate the current study context, providing a cost-effective method for valuation.

  • Local conditions were integrated into the valuation analysis utilizing stakeholders' preferences through multi-criteria decision analysis and willingness-to-allocate assessments, ensuring community engagement throughout this process.

2.3 Benefit Transfer Methodology

  • A systematic literature review was conducted to identify dollar valuations associated with various ecosystem services, collecting critical data points such as:

    • Publication year

    • Study site description

    • Sample size and geographic representation

    • Valuation methods utilized

    • Value estimates normalized into common units of $ (2020) per hectare

  • Total benefits were computed by multiplying average ecosystem service values by the natural marsh and living shoreline areas.

2.4 Field Data Validation

  • Field verification of living shorelines took place between June 2022 and May 2023 using ArcGIS Field Maps and handheld GPS tools for accurate delineation of boundaries and condition assessment.

2.5 Adjustments for Local Conditions

  • Adjustments were made based on:

    • High-resolution data of marsh extent collected through remote sensing

    • Additional marsh characteristics including flora and fauna diversity

  • This localized approach resulted in varying implications for service values associated with storm risk reduction, fish habitat enhancement, and recreational services.

3. Results

3.1 Ecosystem Service Valuation Outcomes

  • The adjusted estimates indicate that annual benefits total approximately $87,643,096 for the Middle Peninsula, representing about 3.26% of the regional GDP

  • Key findings include:

    • Storm risk reduction services made a significant contribution, estimated at over $49 million annually

    • The benefits from recreational fishing were notably underrepresented in traditional assessments, reflecting stronger demands from local stakeholders and emphasizing the need for comprehensive evaluations of community preferences.

3.2 Spatial Variation Insights

  • The analysis revealed that storm risk reduction and other ecosystem services exhibited spatial variations owing to local environmental characteristics that shape differences in service values across the study area.

3.3 Future Service Value Projections

  • Projections indicate sustained increases in marsh habitats by 70% by 2050, predicated on planned restoration efforts via living shorelines that aim to enhance ecosystem functions and community resilience.

  • The study employed in-depth analysis of net changes in service values, adjusting projections for potential future distributions while considering discount factors that account for time-based valuations.

3.4 Community Engagement and Survey Outcomes

  • Engaged stakeholders expressed a higher preference for storm damage reduction services compared to other ecosystem services, highlighting community priorities toward disaster preparedness and resilience.

  • The qualitative insights gained from community input reflected significant factors influencing environmental policy formulation, showcasing the necessity for inclusive, community-oriented decision-making processes.

4. Discussion

4.1 Mixed Methods Approach

  • The application of a mixed-methods approach underscores the value added through interdisciplinary techniques in ecosystem service valuation, facilitating a broader framework for ecological management planning.

  • The findings underscore the critical economic benefits derived from marshes and living shorelines, warranting greater recognition in decision-making processes that often overlook the cumulative advantages when presented at an individual parcel scale.

4.2 Substitutability of Engineered Ecosystems

  • The study assesses the effectiveness of living shorelines relative to existing natural marshes, considering potential discrepancies in timing and service provision.

  • A central insight of the study is that future marsh conservation and restoration strategies hinge on enabling landward migration in response to rising sea levels to sustain crucial ecological functions.

4.3 Conclusory Recommendations

  • There is a pressing need for greater identification and appreciation of the diverse ecosystem service benefits that marshes provide. Alongside stakeholder education, this recognition is essential to fostering support for enhanced coastal resilience and the implementation of sustainable environmental policy measures.

This detailed approach serves to assess the implications and applications of living shorelines in coastal ecosystem management while highlighting the pronounced fiscal benefits associated with preserving and enhancing marsh ecosystems, ultimately aligning ecological, economic, and social welfare objectives effectively.