Stable Riverbanks Help Farmers Make Hay

Today we are hearing from Melanie Carter, a Partners for Fish and Wildlife Program Civil Engineer with the Virginia Field Office, stationed in Southwestern Virginia. I specialize in aquatic habitat restoration in the Upper Tennessee River Basin. 

We hear complaints from farmers when riverbanks erode into their hay fields. As the bank retreats, trees fall into the river and valuable productive land is lost. Animals like muskrats start burrowing into the vertical bare soil, creating holes in the field. Rainwater enters the holes, perpetuating bank instability. Land along the river becomes dangerous for farming equipment access. The worst part about bank erosion is that the river is now overwidened and can’t access its floodplain during high flows. Nourishing nutrients and fine sediments are no longer deposited in the field to replenish the soil and productivity declines.

On Copper Creek, this farmer had lost over 20 feet of his hay field from loss of riverbank and burrowing critters (Melanie Carter, USFWS Civil Engineer)

On Copper Creek, this farmer had lost over 20 feet of his hay field from loss of riverbank and burrowing critters (Melanie Carter, USFWS Civil Engineer)

The Partners for Fish and Wildlife Program collaborates with farmers in the Upper Tennessee River Basin to restore riverbanks using bioengineering techniques. In this watershed, there are over 30 fish and mussel species listed as endangered or threatened under the federal Endangered Species Act, making stable riverbanks essential to protect these species.

Our restoration projects begin with stabilizing the toe of the riverbank at is original location. We use a mix of materials such as boulders, coir logs, or large woody debris, in order to provide habitat along the river’s edge for fish and macroinvertebrates. Next, soil is added in lifts behind the toe protection to reduce sediment entering the river during construction. Riverbanks are returned to a more gentle angle to allow vegetation to establish. And riverbank height is adjusted to ensure a connection between the river and its floodplain.

Riverbank restoration in progress, showing boulder and coir log toe protection with soil lift installation. (Zack Edwards, USFWS Volunteer).

Native woody vegetation, such as willows and elderberry, are most effective at keeping banks in place, preventing erosion as well as providing habitat for birds and pollinating insects. We also encourage the farmer to create a riparian buffer along the river. You don’t need large hardwood trees to hold things together! Small shrubs and trees work just fine, reducing the shading effects on the field. Many of these species bear fruit and nuts that the farmer can harvest or enjoy the wildlife they attract.

After riverbank restoration, large woody debris and coir logs create aquatic habitat along the river’s edge, while native vegetation protects the bank from erosion and animal burrowing activities (Rose Agbalog, USFWS Biologist)

Saving the Horseshoe Crabs for the Birds

Sometime in mid-May, Beth Freiday hopes to see New Jersey’s bayside beaches turn a dusky olive color.

“At the peak of horseshoe crab spawning season, the beaches are almost green from the quantity of eggs and crabs covering the sand,” explains Freiday, a U.S. Fish and Wildlife Service biologist based in New Jersey.

While green beaches are an interesting sight in their own right, it’s what they signify that Freiday cares about – an abundance of crab eggs for migratory shorebirds like the threatened rufa red knot to feast on during their stopover in the Delaware Bay.

The beaches along Delaware Bay are some of the most critically important stopover sites for migratory shorebirds, many of which are undergoing alarming declines. Without a jumbo snack of horseshoe crab eggs, these birds might not make it on their long-distance migration.

To help, the U.S. Fish and Wildlife Service is working at numerous sites along the Delaware Bay to restore beaches and improve conditions for spawning horseshoe crabs, thereby helping support migratory shorebirds.

Horseshoe crabs spawning in Delaware Photo credit: Gregory Breese/USFWS

Fortifying Beaches

At one such site, Freiday is coordinating a partnership with the American Littoral Society and others to restore a 1.5-mile stretch of New Jersey shoreline severely damaged by Hurricane Sandy. These beaches saw a loss of 2 to 3 feet of sand, with the sand pushed so far above the high tide line that spawning crabs could no longer reach it.

To remedy this, the partners are trucking in sand from a local sand mine and moving it onto the beach with a bulldozer, using lightweight pieces of equipment to spread it. Work started at the end of March at Cooks and Kimbles Beaches in Cape May County and is expected to last until mid-April.

All told, approximately 12,000 cubic yards of sand will be spread across the two beaches, which together span 5.5 acres.

“We’re very careful of ecological and historical resources at the sites,” says Freiday, noting that the most environmentally appropriate methods are used for replacing the sand.

While Hurricane Sandy initially wiped out these beaches, Freiday says the problem is persistent.

“Since Sandy, we have had some destructive winter storms that move sand from the beach into the adjacent marsh,” she explains. “This leaves not enough sand on the beach for crabs to spawn, and the sand that is moved into the marsh is no longer accessible for crab spawning.”

It might be something to get used to with a changing climate. The mid-Atlantic Coast is expected to experience some of the fastest rates of sea-level rise in the United States, with more intense storms like Hurricane Sandy battering coastlines.

Restoring Cooks Beach in New Jersey Photo credit: Elizabeth Freiday

Connecting the Dots

Horseshoe crabs are not endangered, though they are under harvest restrictions in New Jersey and Delaware. They experienced a rapid decline from overharvesting in the 1990s. Then came Hurricane Sandy, which demolished 70 percent of New Jersey’s key horseshoe crab habitat.

Since horseshoe crabs don’t start breeding until at least 9 years of age, population increases might not be noticeable for a while. But the good news is they produce upwards of 100,000 eggs in a season – as long as they have access to the sand habitat they need.

Freiday’s team is planning to have all the sand spread and ready for spawning horseshoe crabs by April 15.

“We don’t know exactly when the horseshoe crabs will come up onto the beaches to lay eggs – it all depends on water temperature,” explains Freiday. “We usually estimate May 1, but this year the water is warmer so it could be sooner. We want to be ready.”

After the horseshoe crabs come in to lay eggs, the migratory shore birds will show up – hopefully by the thousands. And the tourists soon follow.

Ultimately, restoring these beaches will not just benefit horseshoe crabs and migratory shorebirds, but also the people who live, work and recreate here. Benefits to people include greater protection from storm surges, improved beach areas for public recreation, and the economic benefits of beach and wildlife-related ecotourism, valued at $522 million in New Jersey’s Cape May County alone.

Endangered rufa red knot at Mispillion Harbor, Delaware. Credit: Gregory Breese/USFWS

Horseshoe crab eggs provide a vital food source for rufa red knot and other shorebirds Photo credit: Gregory Breese/USFWS

This restoration work is being funded by the Department of the Interior through the Disaster Relief Supplemental Appropriations Act of 2013. Partners include the Fish and Wildlife Service, the American Littoral Society, the New Jersey Department of Environmental Protection and the Army Corps of Engineers. Additional work has been coordinated with the National Fish and Wildlife Foundation NFWF and the Conserve Wildlife Foundation of New Jersey.

Conserving Their Home and Ours

The aerial view of an Atlantic coast saltmarsh depicts an intricate labyrinth of marshland grass and sediment. From 20,000 feet the marsh appears static, unchanging. Yet at ground level, there is an evolving struggle for survival that happens twice a day during high tide.

As high tide flows into a Connecticut coastal marsh, young saltmarsh sparrows keep their heads above water. Credit: Jeanna Mielcarek/UConn SHARP

In a recent PBS documentary episode “Animal Homes: Location, Location, Location,” the drama plays out as a female saltmarsh sparrow is shown strategically weaving her nest into the top layer of marsh grass. Her goal is to build her nest high enough to protect offspring from the danger of high tide. But the combined forces of climate change, rising sea levels and increased storm intensity have caused nest flooding to become a very real threat. Hatchlings are unable to climb out of the nest until they are about five days old, according to Chris Elphick, a U.S. Fish and Wildlife Service partner and Associate Professor of Ecology and Evolutionary Biology at University of Connecticut. So many may not survive to see low tide or their mother’s return to the nest.

From Maine down to Virginia, salt marshes provide a home to species like the saltmarsh and seaside sparrow and act as a buffer to counter the effects of sea-level rise and storm surge. In Hurricane Sandy’s wake, many of these coastal areas have deteriorated, leaving both wildlife and people more vulnerable to the forces of future storms.

Newly hatched salt marsh sparrows nestle together in the temporary safety of their nest at Barn Island WMA. Credit: Margie Brenner/USFWS

Three projects included in a larger research study, A Stronger Coast, are supported through federal funding for Hurricane Sandy recovery and work together to pinpoint coastal refuge lands’ strengths and weaknesses along more than 70 miles of shoreline. A portion of these efforts will also determine the current stability of 30,000 acres of Atlantic coastal marshes. Staff and partners are using the latest monitoring technology and surveys to analyze current status, changes and trends for sandy beach shoreline, dunes, coastal marshes, and waterbird populations, which builds on data gathered more than a decade by the Refuge System’s Inventory and Monitoring (I&M) program. Collectively, this will provide critical scientific information to help manage refuge lands, waters, plants and wildlife for future conservation.

A Nelson’s sparrow and a saltmarsh sparrow at Barn Island in Conn. Credit: Chris Elphick/Associate Professor of Ecology and Evolutionary Biology

Elphick, who is a research partner in another Hurricane Sandy funded tidal marsh bird research project, says studying the saltmarsh sparrow can provide important information about the ecosystem as a whole. His work is connected to a program founded by a group of academic, governmental and non-profit collaborators known as SHARP – the Saltmarsh Habitat and Avian Research Program – which provides critical information for the conservation of tidal-marsh birds. Understanding saltmarsh ecology, Elphick says, also helps scientists understand how the resource contributes to a range of vital natural benefits, from human food consumption to recreation.

In the end, the simple truth is that the steps we take to conserve the saltmarsh sparrow’s home can help conserve our homes, too.

Read more about the SHARP program’s work

View photos from the Stronger Coast projects