Taking marsh restoration to a new level

The author at the project site. Credit: Dagny Leonard

As part of “Building a Stronger Coast” month, we’ve asked Erik Meyers, with The Conservation Fund, to share his thoughts on a marsh restoration project that the Fund is leading at Blackwater National Wildlife Refuge in Maryland. Erik is vice president for climate and water sustainability at the Fund.

“But it’s not Yosemite!” friends sometimes blurt out when I speak glowingly of Blackwater National Wildlife Refuge. “No,” I respond, “it’s better.”

Few places on Earth better convey nature’s timeless beauty, productivity … and fragility. Here at Blackwater, soft green marsh grasses spread toward a distant horizon; small salt-marsh birds dart in and out of view; tree islands and forest fringe frame views of the marsh and coastal rivers — all competing for attention with majestic eagles soaring in dramatic Chesapeake skyscapes. Not for nothing is Blackwater frequently called the “Everglades of the North.”

Seaside sparrows nest in the salt marsh at Blackwater Refuge. Credit: USFWS

I’ve learned to look closer, however, and see what’s changing as well. Sometimes the change comes gradually—a ghost forest where there was a healthy stand of pines five years ago. Sometimes change comes suddenly—last year’s solid salt marsh now pocked with small pools of open water. The evolution of this landscape, formed after the retreat of the last major glacier in North America some 10,000 years ago, is accelerating due to the rising level of the Chesapeake Bay and Atlantic Ocean.

Sea-level rise models predict that Blackwater will be dramatically altered over this century, much more than at any point in recent history. An assessment by The Conservation Fund and others signaled the need to act now to hold onto these marshes, including ensuring space for the marsh to relocate, or “migrate,” inland as sea level rises. As important as they are to wildlife, salt marshes also serve people, buffering storm surge and wave action and absorbing flood waters.

Blackwater National Wildlife Refuge, Maryland. Chesapeake Bay.

In addition to offering important wildlife habitat, salt marshes like the one at Blackwater absorb floodwaters and storm surge, protecting coastal property. Credit: Whitney Flanagan

A core project team of staff from the refuge, Audubon Maryland-DC, and The Conservation Fund, along with strong technical and citizens advisory groups, developed science-based, comprehensive strategies to help the marsh adapt. There were three objectives:

  • Hold the most-promising marsh-migration corridors in open-space uses.
  • Help former upland areas become new, high-quality marsh.
  • Slow the loss of existing high-quality salt marsh in strategically targeted areas.

A grant from the National Fish and Wildlife Foundation, supported by federal funds for Hurricane Sandy recovery and resilience, provided an unprecedented opportunity to apply and evaluate these strategies. The centerpiece of our project, completed in 2016, involved using Blackwater River sediment, which is mostly disintegrated upstream marsh, to raise the surface level of 40 acres of strategically located Refuge salt marsh.

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Depositing Blackwater River sediment on the marsh to raise its elevation. Credit: Dave Harp, Chesapeake Photos

Pioneering scientific research suggests that native marsh grasses are most productive at a higher point in the tide range. With the elevation of the marsh surface, we expect native grasses to increase root growth, or “biomass,” and “lift” themselves higher over time. Maintaining productive native marsh plants is key to helping marshes rise along with future sea level.

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While we will continue to monitor and evaluate the project, to date, the results have exceeded our expectations. Added sediment settled out to target levels. Existing native grasses have flourished, and new plants added over the summer have taken root. Breeding pairs of seaside sparrows are already back using the site.

These outcomes are due to incredible partners at the refuge, the Fish and Wildlife Service Northeast office, Audubon Maryland-DC, and other federal and state agencies — a social ecosystem nearly as vital as the natural system we’re all trying to conserve, enhance, and adapt.

So, no, it’s not Yosemite; it’s better.

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