Coastal ecosystems in Massachusetts provide many services to coastal communities, including critical habitat, carbon capture, floodwater retention, and storm buffering capacity. Salt marshes are particularly effective at buffering against storms—their vegetation lessens the force of waves (Iris et. al., Nature Geoscience, 2014). Salt marshes that are unable to adapt will eventually become mudflat habitat (MCCA, 2022, Volume II, p. 94).

In addition to the many ecosystem services, coastal wetlands store water that is then filtered and purified as it moves through the hydrological cycle. Wetlands and marshes serve as habitat for many birds – such as the saltmarsh sparrow which is of special concern in Massachusetts – and for juvenile fish before they enter open waters (MCCA, 2022, Volume II, p. 94). Residents of the state as well as visitors enjoy the recreational and cultural benefits provided by these ecosystems, such as hiking, boating, and birdwatching. 

Guided Exploration:
Identifying coastal ecosystems in your community, and which “services” those ecosystems might be providing, is an essential piece of local adaptation planning. This exploration provides mapping and questions for your consideration.

Open the GEAR Ecosystems Map and select a municipality. Expand the Ecological Resilience and Biodiversity Layers group and turn on the MassDEP Wetlands layer. (Please note, while some of the critical ecosystems in your community may be visible here, some may not be mapped). Consider the following questions:

• What might the main functions of these wetland ecosystems be in your community?
• Consider which ecosystems are more resilient to the changing climate by toggling on and off additional coastal ecological resilience biodiversity layers, including:
• BioMap Core Habitat Components
• BioMap Local Level Components

Turning on the Protected and Recreational Open Space layers, you can look at which sites already have some form of protection and who owns them, to consider:

• Which of these ecosystems are part of the public open space network, including trails and similar community assets?
• Which of these ecosystems would the community like to be part of that network?

Coastal ecosystems adjacent to developed areas are especially vulnerable to sea level rise and coastal flooding because there is limited space to migrate inland due to obstacles such as roads, lawns, and parking lots. While some coastal ecosystems, such as salt marshes, could adapt to sea level rise by increasing elevation through sediment capture or migrating inland, even coastal ecosystems adjacent to non-developed, natural open spaces face relatively rapid sea level rise and may not be able to adapt fast enough. All coastal ecosystems in Massachusetts are at risk of eventually transitioning to mudflats or open water in the long-term. Removing barriers allows marshes to migrate inland as a natural response to higher sea levels.

Transition of salt marshes to mudflats and open water is an example of ecosystem conversion. Rapid conversion results in a pronounced loss of ecosystem services, resulting in potential coastal erosion and flooding, saltwater intrusion into drinking water supplies, critical habitat loss (such as important nesting areas for birds), and less carbon sequestration. It is projected that 98% of the state’s high and low marsh habitats will transition to tidal flats by 2100 (MCCA, 2022, Volume II, p. 95).

Proactive planning, conservation, and preservation of vulnerable coastal ecosystems is critical to reduce further harm and negative consequences.

Guided Exploration:
This exploration will help you identify particularly vulnerable coastal ecosystems in your community, where ecosystems should be conserved, and where they might need restoration and protection.

Open the GEAR Ecosystems Map, select a municipality, and toggle on/off the Coastal Flooding layers under the Climate Hazard Data group– this includes Coastal Flooding Projections and Worst-Case Hurricane Surge Inundation Zones.

• Identify which areas are projected to be within areas of flooding - consider the extent of inundation of these ecosystems by 2030, 2050, and 2070.
• Consider whether there are coastal ecosystems currently providing flood protection to adjacent neighborhoods with high flood risk (i.e., where do wetlands and flood zones overlap)?

Now toggle on the layers in the Protected and Recreational Open Space group to consider:

• Is there land adjacent to these ecosystems that may allow them to migrate (or move inland) in response to rising waters?
• How can your community start planning for inland migration of coastal ecosystems? How can marsh-adjacent areas be protected or restored?
• Are there ways to plan for this as your community also meets demands for new, sustainable development?
• Explore layers in the EJ and Other Priority Populations group to help think about who might be most impacted by coastal flooding in your community.
• How might restoration of coastal ecosystems be planned to create benefits for environmental justice and other priority populations?
• What technical assistance is available as your start planning?
  
• The Massachusetts Office of Coastal Zone Managment (CZM), along with other agencies, such as the Department of Environmental Protection (DEP) and the Division of Ecological Restoration (DER), coordinate to promote and implement coastal wetland protection and restoration projects.
• Are there other local organizations or individuals you can identify?

Read More About Related Impacts in the Massachusetts Climate Change Assessment:

• Coastal Wetland Degradation page 94 (top impact Statewide; North & South Shores; Cape, Islands, & South Coast regions)
• Coastal Erosion page A95 (top impact Cape, Islands, & South Coast regions)
• Reduction in Clean Water Supply page A60 (top impact Berkshires & Hilltowns; Cape, Islands, & South Coast regions)