Future of coastal marshes lies in the hands of private property owners

Findings from a study published this week in the online edition of the Proceedings of the National Academy of Sciences offer broad implications for how to best design programs to mitigate climate change effects. The study recognizes that private landowners will be critical partners in efforts to save coastal marshes in the face of climate change and rising sea levels.

Based on the results of a survey of more than 1,000 owners of Connecticut coastal properties, landowners harbor skeptical attitudes about granting easements, based on concerns that they will not be offered a fair price in exchange for keeping land as open space where marshes can migrate as sea levels rise. They also worry that environmental organizations that obtain the easements “might not act fairly or transparently in their efforts to encourage tidal marsh migration,” the researchers write.

“The findings strongly suggest that relying on education about sea-level rise and the ecosystem benefits of marshes alone will not protect land from changes brought on by storms and climate change,” said Ashley Dayer, assistant professor of human dimensions in the Virginia Tech College of Natural Resources and Environment’s Department of Fish and Wildlife Conservation. “Instead, conservation strategies for marsh migration inland in the face of sea-level rise will need to be attractive to private landowners and encourage their voluntary participation.”

In the study area — the Connecticut coast — there are an estimated 30,000 landowners in the zone projected to become tidal marsh by 2100, and millions of people globally live near tidal marshes. Whether landowners decide to leave room on their land for marshes to move inland or instead build seawalls that harden shorelines means either protecting tidal wetlands and their many ecological, economic, and recreational benefits, or losing them altogether.

“As both coastal communities and tidal marshes deal with increased flooding, the responses of landowners will likely constrain marsh migration across large swaths of coastline,” said lead author Christopher Field, a post-doctoral fellow in the University of Connecticut’s Department of Ecology and Evolutionary Biology. “This finding hints at big challenges ahead for a variety of coastal ecosystems that may not have many places left to go to escape accelerating sea-level rise.”

The survey was conducted following two major storms — Hurricane Irene in 2011 and Hurricane Sandy in 2012 — so the results are a valid measure of whether that experience influences attitudes about taking action to lessen future risks, according to researchers.

While landowners whose properties flooded during Hurricane Sandy were 1.4 times more likely to say they may be willing to sell their vulnerable land outright, this result may overstate what people would actually do. For example, although the study did not investigate past landowner behavior, the researchers note that fewer than 100 properties in the study area were acquired during federal buyout programs implemented after the recent hurricanes, though many more were eligible.

If land protection agreements with nonprofits and government agencies aren’t the answer, what offers more promise for the future of marshes?

Surveyed landowners responded favorably to the idea of restrictive covenants, even though they typically do not include financial incentives. Under restrictive covenants, an entire neighborhood agrees to forgo building seawalls and other shoreline armoring structures. These armoring strategies can be damaging in the long run, because they can divert erosion and flooding to adjoining properties and natural habitats.

Coastal landowners also liked the notion of future interest agreements. Under these programs, private landowners agree to accept fair market value of their property at the time of signing if future flooding reduces the value by more than half. That future flooding would allow dry upland to turn into coastal marsh.

“Coastal flooding is increasing in many places along the U.S. east coast, with repercussions not only for the people who live there, but for the natural resources that many people value,” said Chris Elphick, professor with the University of Connecticut’s Department of Ecology and Evolutionary Biology. “Several species of birds that live in coastal marshes, for example, have declined dramatically in recent years, and extinctions are likely if we don’t find ways to protect their habitat.”

“In sum, our findings indicate that current conservation strategies may not interest enough landowners to allow marsh migration at the scales needed to mitigate losses from sea-level rise,” concluded Dayer, who is affiliated with theGlobal Change Center, housed in Virginia Tech’s Fralin Life Science Institute. “Less common strategies that have more support from landowners will need to be considered. This is yet another example that incorporating information about human interests and behaviors into conservation planning is essential to securing conservation outcomes.”

This study was funded by Connecticut Sea Grant, the University of Connecticut, the Connecticut Department of Energy and Environmental Protection, and the Robert and Patricia Switzer Foundation Environmental Fellowship.

For a copy of the study, “Landowner behavior can determine the success of conservation strategies for ecosystem migration under sea-level rise,” send a request to [email protected].