Eco-Restoration Journey Week 23: Plant surveys document the new green scene

When Harwich Conservation Trust’s Hinckleys Pond — Herring River Headwaters Eco-Restoration Project got going in March, it’s fair to say that the area looked a bit like a moonscape. Layers of sand built up over years of cranberry farming had been removed from the site, and the ground had been roughened in a process called microtopography.

But a green fuzz soon began to overspread the area, courtesy of a long dormant native seed bank that suddenly had the sun and water it needed to spring to life.

And over the next few months, this new growth began flourishing at an astonishing speed. Aided by hundreds of new plantings that were part of the project’s design, the Hinckleys Pond — Herring River Headwaters Preserve is now a green place, filled with a variety of native plants.

An important part of the project is knowing what plants were there before the project began, what is there now, and what changes we may see in the future. A team of plant ecologists from the Association to Preserve Cape Cod (APCC) and Inter-Fluve, the specialty engineering firm that is a key partner for the Hinckleys Pond project, have conducted plant surveys to document these changes. They were at the site last week conducting another survey.

We reached out to Sarah Klionsky, a Wetland Ecologist for Inter-Fluve, with some questions about the team’s work. Here are her replies, with some additions by Annie Spangenberger, an Ecologist for Inter-Fluve.

What is the scope of the plant survey work at the Hinckleys Pond — Herring River Eco-Restoration Project?

We surveyed the vegetation at the Hinckleys Pond bogs in 2024 before construction began on the restoration project. We returned this year to document the first growing season post-restoration, and we will return again next year to gather data on the second growing season. We survey vegetation using 3 x 3 m fixed plots, meaning that we return the same location each year. Because the Hinckley’s bogs each had one section in which sand was removed and another section with no sand removal, we purposely located plots in both sections. Across Jenkins and Warner Bogs, we have 45 vegetation survey plots.

What is the goal of the plant survey project?

There are several goals of survey vegetation at restored bog sites, including Hinckley’s. Pre- and post-restoration surveys allow us to monitor changes in the plant community as a result of the restoration project and over time and track whether and how restoration increases plant diversity.

Additionally, we are able to better understand the characteristics of the species that grow at the site after restoration. For instance, we can determine whether the plant community is more indicative of a wetland system or an upland system, and cranberry bog restoration projects often have a goal of restoring a wetland ecosystem. We can also look at whether plants are native or non-native, annual or perennial.

At Hinckleys in particular, we will be able to compare the plant community in the sand removal and non-sand removal sections. Although we would need more sites with paired removal and non-removal sections to make strong conclusions about the effect of sand removal, we can definitely see patterns of how vegetation differs in the two sections based on our Hinckley’s survey.

Finally, by collecting vegetation data using the same method that is being used at many retired and restored bogs on Cape Cod and in Southeast MA, we can add our data to a larger dataset that can be used to gain a more comprehensive understanding of the trajectory of plant communities in restored cranberry bogs.

What kinds of plants did you document on the most recent plant survey last week?

Some of the most common species we encountered included Canada rush (Juncus canadensis), toothed flatsedge (Cyperus dentatus), false water-pepper smartweed (Persicaria hydropiperoides), fall panicgrass (Panicum dichotomiflorum), poison ivy (Toxicodendron radicans) and common barnyard grass (Echinochloa crus-galli). The latter is a non-native species that I have rarely seen at other restoration sites. These are only a few of the many species that germinate quickly after restoration.

Some of the other species we encountered, which frequently germinate at restored sites included pointed broom sedge (Carex scoparia), swamp yellow-loosestrife (Lysimachia terrestris), switch panicgrass (Panicum virgatum), dwarf St. John’s-wort (Hypericum mutilum), lance-leaved violet (Viola lanceolata), and two species of dewberry (Rubus hispidus, R. flagellaris). Of course, there is still some cranberry present. It’s also worth noting that black chokeberry (Aronia melanocarpa) was one of the most commonly encountered species at Warner Bog.

Do you anticipate a “succession” pattern of growth at the Hinckleys Pond project area? Will other plants appear in the mix as time goes on?

Yes, I do anticipate that the plant community will continue to shift over time. At other sites, we haven’t found a lot of change until year 4 or 5 after restoration. Many species will remain, but there will also be some turnover and some changes in abundance.

For instance, Canada rush (Juncus canadensis) is often very abundant shortly following restoration, but after a couple years, it declines in abundance and common soft rush (Juncus effuses) increases in abundance.

Because cranberry bog restoration is so new, there is only one site in the state that has been restored for more than 10 years, so it is harder to predict what will happen over a long period of time. It will be very interesting to see how the vegetation at Hinckley’s Pond continues to change.

Project refresher

The Hinckleys Pond – Herring River Headwaters Eco-Restoration Project includes the restoration of two retired cranberry bogs that bookend 174-acre Hinckleys Pond in Harwich, located at the headwaters of the Herring River estuary. Hinckleys Pond is also connected by streams to river herring spawning habitat in Long Pond and Seymour Pond.

By the late 1990s, much larger off-Cape bogs were producing an extra supply of cranberries that caused the price to fall. This shift in the industry makes it more difficult for local growers to continue farming. Some are looking to exit the industry.

Farmers have a choice. They can either sell their properties for conversion of the upland to subdivisions which can cause water quality changes and end up closing off public access to the land. Or they can seek a conservation future by selling to local land trusts and towns. In 2021 at Hinckleys Pond, the Jenkins family finished their farming chapter and chose to sell their 31 acres to HCT for the next chapters of conservation and eco-restoration.

The Brown family, who owns a retired bog on the other side of the pond, is also partnering with HCT on the project. The collaborative eco-effort will increase biodiversity and restore freshwater wetland habitat as well as enhance opportunities for everyone to enjoy the trails, views and wildlife watching.

The eco-restoration project is funded by HCT donors, the Brown family, U.S. Environmental Protection Agency (EPA) Southeast New England Program (SNEP) Watershed grant, EPA National Estuary Program Coastal Watershed grant under cooperative agreement with Restore America’s Estuaries, Massachusetts Department of Conservation & Recreation MassTrails grant, foundation funds through the Association to Preserve Cape Cod, and a Transformational Habitat Restoration & Coastal Resilience grant through the National Oceanic & Atmospheric Administration.

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