Will Marshes Rise to the Challenge of Rapidly Rising Seas?

* All information presented by the National Estuarine Research Reserve Association

As the rate of sea level rise quickens around the country, a pioneering study published in Biological Conservation examines the ability of tidal marshes to keep pace. Conducted by the National Estuarine Research Reserve System, this first-in-the-nation assessment reveals that marshes along the Pacific Coast appear more likely to survive than those along the Atlantic. Two marshes in southern New England were found to be the most vulnerable of those evaluated.

Using data from the System-wide Monitoring Program, Research Reserves conducted this study at 16 sites in 13 coastal states. It was based on an innovative approach that evaluates the ability of tidal marshes to thrive as sea levels rise according to five categories of resilience: marsh elevation; change in elevation; sediment supply; tidal range; and rate of sea level rise.

“This study shows that not all tidal marshes are equally vulnerable to sea level rise,” says Rebecca Roth, executive director of the National Estuarine Research Reserve Association (NERRA). “It also gives coastal managers the capacity to understand and compare the ability of marshes to persist in the face of rising seas. This will inform decisions focused on protecting marshes for generations to come.”

Tidal marshes provide many benefits to nearby communities. They protect people and property against storm surges and flooding, improve water quality, and create habitat for commercially important fish and wildlife. For millennia, most marshes have kept pace with rising seas by increasing in elevation.

With sea levels projected to increase much faster in the future, the fate of many marshes is now uncertain. The ability to understand and compare the likelihood of marshes to persist in the face of rising seas can inform strategies to protect them. For example:

• Marshes found to be highly resilient are likely to thrive and provide value for a long time; ensuring that they are protected is a good investment for the future.
• Moderately resilient marshes can survive if actions are taken to help them thrive, such as reconnecting them to the rivers that nourish them with sediment.
• The least resilient may not survive in their current locations; they might be saved through intensive management strategies or by finding opportunities for them migrate to higher ground.

“We are committed to building on this study to deepen our understanding of marsh resilience across the nation,” says Cory Riley, NERRA president and manager of New Hampshire’s Great Bay Reserve. “Our network’s capacity to conduct consistent environmental monitoring across a network of sites allows Reserves to act incubators for new methodologies that scientists and decision makers can use to answer critical questions about how our coastal areas are responding to climate change and development.

From federal agencies managing national refuge networks to managers of individual sites, anyone with the relevant data can use this new approach to compare marsh resilience at the local, state, regional, or national levels.

Contacts

Rebecca K. Roth, Executive Director
National Estuarine Research Reserve Association
202.236.4819
roth@nerra.org

Cory Riley
Manager of Great Bay Reserve, can provide management perspective on significance of study
Great Bay Reserve, NH
Cell. 240.271.6740
Cory.Riley@wildlife.nh.go

Images available at https://www.flickr.com/photos/144565486@N08/collections/72157674643549790/