For almost two decades, state and federal partners have worked to rebuild Poplar Island in the Maryland waters of the Chesapeake Bay. Once home to a sawmill, a general store and a schoolhouse, the island succumbed to sea level rise, shrinking to a fraction of its size by 1996. Rebuilt using sand and sediment dredged up from the bottom of the Bay and hand-planted with native marsh grass, the island has become a refuge for 175 species of shorebirds, songbirds, waterfowl and raptors.
Eastern bluebirds, black ducks and snowy egrets are among the birds that nest on Poplar Island, but it is the osprey whose presence stands out. Their sprawling nests can be found on wooden platforms, abandoned barges and Bay-side rip-rap. Plentiful food and nesting space mean Poplar’s osprey population is healthy, and can give researchers like Rebecca Lazarus an idea of what the birds should look like under the best environmental circumstances.
Working with the U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (USFWS), Lazarus is studying contaminant exposure in osprey around the Bay. Because the birds sit at the top of the food chain, their health is an indicator of environmental problems. Tracking the buildup of chemical compounds in the eggs and blood of birds that Lazarus calls a “sentinel species” can tell us what toxics are present in our rivers and streams.
Lazarus started her season of research when ospreys returned to the Bay in mid-March. The University of Maryland doctoral candidate and USGS employee visited nests, counted eggs and watched the ospreys grow.
Once the chicks hatched, Lazarus used motion-activated game cameras to monitor their diets. The birds on Poplar eat almost exclusively striped bass and menhaden, reminding us that the management of these two fisheries has a big impact on the balance of the Bay ecosystem.
As the chicks grew, Lazarus tagged each one of them with a metal band. She measured their weight and culmen length, and took samples of blood to test for chemical contaminants.
The last large-scale study of contaminant exposure in osprey was conducted close to a decade ago, and found elevated concentrations of polychlorinated biphenyls (or PCBs) and flame retardants in egg samples from the Anacostia and middle Potomac rivers. Lazarus hopes her updated research will show us what contaminants persist in the watershed, posing potential threats to wildlife and human health.
The birds on Poplar are healthy and serve as a benchmark against which Lazarus can compare those that nest in more polluted parts of the Bay. Ospreys experienced such a strong population boom after the United States banned the insecticide DDT and other contaminants that they are now nesting along urbanized waterways where dense development, wastewater treatment plants and the flow of pharmaceuticals and other new toxics into our water have concern about their potential to thrive.
By monitoring the link between clean water, contaminant-free fish and healthy osprey, Lazarus has taken a holistic approach to her research. Once published, her findings could help state and federal agencies develop plans to mitigate pollution or prioritize contaminants of concern. And they will help improve the environmental quality, ecosystem integrity and sustainability of the Bay.
To view more photos, visit the Chesapeake Bay Program Flickr page.
Images by Steve Droter and Olivier Giron.
Captions by Catherine Krikstan.
Part construction site, part mud pit and part wildlife refuge, the Paul S. Sarbanes Ecosystem Restoration Project at Poplar Island, Md., tackles two unique challenges in the Chesapeake Bay.
First, sand and sediment accumulate in the Bay’s vital shipping channels—particularly during heavy rain events like Tropical Storm Lee in 2011—and threaten to block cargo ships that allow the Port of Baltimore to contribute $2 billion each year to the region’s economy.
On the other hand, sea level rise, sinking land and increasingly frequent strong storms are quickly eroding away the Bay’s few remaining islands, threatening the survival of iconic wildlife species and critical habitat.
Poplar Island, for example, spanned more than 1,100 acres in the mid-1800s and supported a small community of families, farmers and fishermen until it was abandoned in the 1930s. When restoration began in the 1990s, four scattered acres were all that remained—less than half a percent of the island’s historical size.
But the island that was nearly destroyed is now destined to be rebuilt using 65 million cubic yards of sedimentary silt—imagine a giant cube of mud a quarter mile long in each direction—dredged up from the bottom of the Bay.
In 1998, the U.S. Army Corps of Engineers began to construct stone “containment dykes.” The walls are 10 feet tall and surround Poplar Island’s former footprint, and the island has been divided into six massive containment cells for building island habitat.
The western half of the island, surrounded by an inner ring of 27-foot dykes, is being transformed into 570 acres of forested upland island habitat similar to that of neighboring Coaches Island.
Coaches Island, once vulnerable to the same forces that washed away its neighbor, supports upland species like bald eagles and provides a shallow inlet utilized by nesting diamondback terrapins in the summer and migratory waterfowl during winter.
The eastern half of Poplar Island is further divided into 14 “sub-cells” undergoing various stages of wetland construction and management.
Low-lying wetlands are created through a four-step process. First, dredged sediment is brought in on barges by the Maryland Port Administration, mixed into a watery slurry, and pumped into each cell at precise levels.
As the slurry dries, it forms a massive crust—a vast, other-worldly landscape—that is the base for building habitat.
Next, heavy machines carefully grade the crust and excavate ditches that will function as tidal creeks in the completed marsh.
Then a spillway is opened to expose the new landscape to tidal flow, and water is allowed to move between the Bay and the newly built marshland.
Finally, individual plugs of smooth and saltmeadow cordgrass are planted row upon row into the nutrient-rich soil.
These native plants are capable of withstanding strong storms while offering food and shelter to the 175 species of shorebirds, songbirds, waterfowl and raptors that now visit Poplar Island.
Poplar Island's marshes offer protection and isolation from human and mammalian predators, and the open waters along its perimeter provide feeding opportunities for diving ducks like buffleheads, scaups and long-tailed ducks.
The U.S. Fish and Wildlife Service (USFWS) manages the island’s vegetation and wildlife—including less welcome species like the Canada goose. Fences and fluttering pink flags help deter geese and prevent them from overfeeding on expensive marsh grass.
On our visit in January 2013, USFWS wildlife technician Robbie Callahan led a monitoring team to assess the density of muskrat huts in the marsh. The semiaquatic rodents, though a critical part of the wetland ecosystem, are controlled to prevent damage from overpopulation.
The USFWS also monitors avian predators—like the northern harriers that feed on small rodents—and migratory waterfowl, attracted to Poplar Island during their spring and fall trips along the Atlantic Flyway.
With the help of USFWS experts, Poplar Island is able to provide a range of Bay species with the safe nesting habitat that only a protected, well-managed island can.
Even sunken barges—placed here in the mid-1990s as “breakwaters” in an attempt to retain the island’s remnants—have become host to nesting ospreys and black-crowned night herons.
According to the USFWS, Poplar Island is well on its way to becoming a keystone wildlife refuge. “Poplar Island is an important refuge,” said USFWS biologist Pete McGowan, who specializes in waterfowl and island restoration. “There are species that are highly dependent on these remote island habitats. And this is a habitat type that is rapidly disappearing from the Chesapeake Bay. We need to do what we can to maximize the remaining island habitat that we have, and create new island habitat whenever possible.”
The Paul S. Sarbanes Ecosystem Restoration Project is scheduled for completion in 2041, with a final price tag estimated at $1.4 billion over 45 years. Rebuilding Poplar Island is an enormous, expensive and painstaking process—but its virtues of “beneficial use” have been extolled throughout the conservation and business communities alike, and it has become a "win-win" for the Bay and all the watershed provides.
View more photos on the Chesapeake Bay Program Flickr page.
“Everything you film today, everything on camera, everything you walk on, was created. None of it was here in 1998. We’d be in several feet of water right now a little more than a decade ago.” – U.S. Fish and Wildlife Service Biologist Chris Guy
It’s warm for a January morning. But out of habit, the team from the U.S. Fish & Wildlife Service Chesapeake Bay Field Office (FWS) is armed with coffee thermoses and dressed in construction-orange floatation gear. The hot coffee and “survival suits” gain importance as the winter wind stings our faces on the hour-long boat ride from Annapolis to Maryland’s Eastern Shore. The team embarks on this trip most mornings throughout the year, even in the coldest months.
In fact, today’s task must be completed in the first weeks of the new year. We’re hauling discarded Christmas trees to build waterfowl habitat on Poplar Island, a place where, ten years ago, wildlife habitat had nearly disappeared – because the land had disappeared. In 1997, just 10 acres of the original island remained.
Today, Poplar Island has grown to 1,140 acres, thanks to a partnership between FWS, the U.S. Army Corps of Engineers, Maryland Environmental Service and Maryland Port Administration that uses dredge material from the Port of Baltimore to rebuild the island. Many places (such as parts of Washington D.C. and Philadelphia International Airport) have been “built” using this technique, known as “fast-landing.” But Poplar Island is distinctive: it’s being constructed not for human use, but to provide the Chesapeake Bay’s wildlife with island habitat, a rarity in an era of quick-sinking shorelines and rising sea levels.
“What's unique about this project is the habitat aspect,” says FWS biologist Chris Guy, who’s helped run the project since 2005. “It's a win-win, because you get a dredge disposal site, which is hard to come by in the Chesapeake Bay, and it's long term, and you're getting much-needed habitat restoration.”
According to FWS biologist Peter McGowan, who began working on the project in the mid 1990s, wildlife are now flocking to Poplar Island. “Back in 1996, we had ten documented bird species using the island,” he says. “Now we have over 170 species that have been documented, and over 26 nesting species.”
Every January since 2005, residents of Easton, Maryland, have put their old Christmas trees on the curb for trash pickup, unaware of the fact that their discarded holiday greenery will soon become shelter and nesting habitat for black ducks, snowy egrets, red-winged blackbirds and diamondback terrapins.
Like so many Chesapeake Bay islands before it, Poplar Island fell victim to both rapid sea level rise and post-glacial rebound: the counteraction of glaciers during the last Ice Age that’s making the Bay’s islands sink. The combination of rising water and sinking land caused shorelines to quickly erode, and eventually vanish.
Here’s a summary of Poplar Island’s life, near death and revitalization:
How do scientists and engineers turn open water into land you can confidently step on? With dried and processed dredge material that’s used to build up the land over time.
Dredging is a process of clearing sediment (dredge) out of the bottom of waterways. Dredging is necessary on many rivers leading into major ports because sediment naturally builds up over time. This sediment must be excavated so large ships can pass in and out of ports.
Maintenance dredging of the Port of Baltimore is critical to Maryland’s economy: the port contributes $1.9 billion and 50,200 jobs to the state’s economy. It’s also the number one port in the U.S. for automobile exports.
It also contributes a lot of sediment. The port estimates that maintenance dredging in the next twenty years will generate 100 million cubic yards of sediment – enough material to fill the Louisiana Superdome 25 times. Finding a place to store this massive amount of dredge material has been a problem – that is, until the Poplar Island project came calling, requiring 68 million cubic yards of dredge.
When dredge material arrives at Poplar Island through large pipes, it spends a few years drying. Then bulldozers and heavy equipment move in to dig out channels for wetlands and streams. When the topography is set, the area is planted with grasses, trees and shrubs.
A first time visitor to Poplar Island may be surprised to see bulldozers and pipes gushing black dredge material at a site renowned as a world wonder of habitat restoration. Although it’s necessary to use this heavy equipment to rebuild the island, the staff has found a way to balance these activities and still attract wildlife.
“Let's call it a ‘dance,’” says Guy. “We have to work with the construction, obviously, but we have to be sensitive to the needs of the birds.”
The Christmas trees that Guy and McGowan have been bringing to the island since 2005 give black ducks a place to lay their eggs. Black duck populations have fallen dramatically in the Chesapeake Bay region, causing the bird to be listed as a species of concern.
One reason for the species’ decline is a lack of food, including bay grasses, aquatic plants and invertebrates that have dwindled as pollution increased. Development and other human activities have encroached on its wintering and breeding habitats.
“[When we began the project], we looked at what others around the country used to attract nesting birds,” explains McGowan. “Christmas trees were a good resource. Instead of going into landfills, they could be reused.”
Discarded Christmas trees imitate shrubs that black ducks typically seek out. They’re warm, sheltered spots to raise young. Since the first tree plantings on Poplar Island took place just ten years ago, none are mature enough to provide adequate nesting habitat. So until the real trees grow tall enough, Christmas trees will have to do.
“Black ducks like to nest in thickets in the marshes,” McGowan explains. “Christmas trees help provide the structure they need. It keeps them covered and safe from predators.”
And the trees seem to be working. As we take apart last year’s piles, we find a handful of eggs underneath the dead trees.
“Seeing that we have these leftover eggs demonstrates to us that ducks are using these nest piles successfully,” says Guy. “Just about every one of them we find a few eggs, so we think they’re having multiple clutches.”
The eggs we find in the six or seven piles that we disrupt belong to mallards, but McGowan and Guy claim that black ducks are nesting on Poplar Island as well.
“We've had six or seven black ducks nesting on the island,” says Guy. “You may say six or seven isn't a big deal, but when you're down to the last few hundred black ducks nesting in the Bay, going from 0 to 6, where they're used to be thousands, that's a big success story. That's not the only thing that these trees do, but it's one of the main drivers to get these trees out here.”
Guy and McGowan have long envisioned Poplar Island as prime habitat for black ducks.
“Back [in 2005], we went around the curbs in Anne Arundel County and threw the trees in the back of my pickup,” Guy tells me. It took the pair the entire month of January to collect the trees and transport them to Poplar Island.
Seven years later, the project is finished in just one day with help from Easton Public Works and volunteers and employees from FWS and Maryland Environmental Service.
Black ducks aren’t the only critters on Poplar. The island is home to hundreds of birds, reptiles and other species that now rely on the restored landmass for food and shelter.
For more information about Poplar Island and other wildlife habitat restoration projects around the Chesapeake Bay region, visit the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office website.