'Re-wilded'— Transforming Massachusetts Cranberry Bogs Back Into Wetlands

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As the Massachusetts Division of Ecological Restoration’s Cranberry Bog Program released its report this month recounting a decade of restoring former cranberry bogs to wetlands, project research hydrogeologist Christine Hatch and her University of Massachusetts Amherst students are poised to continue collecting data and monitoring the “re-wilded” ecosystems’ progress for years to come. 

Students Alyssa Chase, Jeron LeBlanc and Lyn Watts measure soil moisture along a transect above fiber optic cables at Foothills Preserve, Plymouth, Mass. Photo courtesy: UMass Amherst/Hatch lab

The report was prepared by the Living Observatory, a public interest learning community founded in 2011 to communicate to the public as stages of stream and wetland restoration were completed at a former family-owned cranberry bog, Tidmarsh Farms. It is the largest freshwater ecological restoration ever completed in the Northeast, according to project partner MassAudubon, which created Tidmarsh Wildlife Sanctuary from the eastern part of the 600-acre farm.  

Restoration of the western section of the property, now owned by the Town of Plymouth and known as “Foothills Preserve,” is expected to be complete in January, Hatch points out. “The whole process of transforming Foothills back into a wetland has taken a full calendar year.” 

She adds, “Wetlands don’t form by accident, they form in the presence of very specific geologic constraints. We are exploring techniques and best practices to identify what works in order to turn cranberry bogs back into wetlands. It’s very exciting to see the transformation.”  

Hatch and her students spent the field season just ended – and several before that – locating cold, fresh groundwater and installing water and temperature sensors as four project bogs were reclaimed. The sensors will feed data to Hatch and other scientists who continue research on soil moisture, hydrology, geology and the interaction of surface and groundwater, among other things. One goal is to develop a set of best practices for site evaluation and restoration for future projects, she says. 

“Wetlands don’t form by accident, they form in the presence of very specific geologic constraints. We are exploring techniques and best practices to identify what works in order to turn cranberry bogs back into wetlands. It’s very exciting to see the transformation,” says Hatch.

Restoration leaders have taken results from Hatch and other researchers including fellow UMass Amherst hydrogeologist David Boutt plus researchers at Mount Holyoke College, UMass Boston, Bridgewater State, MIT and Woodwell Climate Research Center, among others. They study soil microbes, vegetation, water chemistry, wetland soil formation and function, invertebrates, wildlife and more. Results provide “a complete vision of the landscape transformations that can occur in these systems,” Hatch points out. 

As the Living Observatory explains, “The findings, many of which are described here for the first time, will help shape future projects. The report concludes with a proposal for a standard monitoring approach for new restoration sites, as well as topics for further research.” The state and its partners hope to eventually restore 900 acres of wetland and to permanently protect 1,800 acres.  

Hatch says, “Wetlands are slow – they sit around and accumulate organic muck, which takes time. They have rough terrain with micro-topography – hummocks with their own micro-climates that the cranberry growers had flattened and taken away. It is a complicated process to restore those ecozones.” For example, cranberry growers used a system of berms and ditches dug into the peat where they could float berries at harvest time, and they applied sand to control pests and anchor the plants.  

“Bulldozers with balloon tires start at one end and work their way across the site, undoing over a century of human land use. These interventions give the area a ‘jump start’ of about a hundred years toward recovery by filling ditches, making stream channels longer and more complex, and adding hummocks back in,” Hatch says. 

“Foothills already has the right mix of soils, and we expect the long-dormant wetland plant seeds to come bursting back to life in the spring, followed by reptiles, amphibians and birds – the whole community.”  

“What’s exciting right now for me and my students is creating experimental microtopography to test how water moves through these sites and cataloging what creatures and plants have returned,” she adds. “We have some initial observations that these techniques work, but this will be the first formal, large-scale controlled experiment with observations before and after, as well as above and below the ground over time.” 

In addition to UMass Amherst and the state’s ecological restoration division, contributing researchers came from dozens of other institutions, volunteers, conservation organizations and state and federal agencies including the Massachusetts Environmental Trust, the Gulf of Maine Council on Marine Environment, the Manomet Center for Conservation Science, The Nature Conservancy, MassWildlife and Ducks Unlimited. 

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