How removing a dam could save North Carolina's ‘lasagna lizard’

The best time for researchers to go for a salamander snorkel safari is in the middle of the night. Eastern hellbenders, a type of freshwater salamander found only in North America, are nocturnal. Hellbender salamanders hide beneath the crevices of large, smooth rocks in the riverbeds of the Appalachian Mountains, making finding them no easy feat.

“You’ve kind of got to get in the mind of the hellbender,” says Robert Adams, an aquatic conservation graduate student at Appalachian State University who studies hellbenders. “If you didn't see the two little eyes and nostrils, then you could easily pass it up as a rock.” 

In late June, Adams and a team of scientists equipped with snorkel masks and waterproof flashlights waded into the Watauga River in wetsuits and knee pads to begin their belly-down search. When someone spotted a hellbender, they raised a half-curled fist—a hellbender “claw” to mimic the lizards’ four-toed front feet—as a signal to the team. Then, the researchers lured the hellbender out from its cozy abode and into a mesh bag.

The researchers captured, tagged, and relocated these salamanders to a different part of the Watauga River in North Carolina while U.S. Fish and Wildlife biologists and engineers carefully deconstructed Shull’s Mill Dam, a defunct hydroelectric dam. The project, led by non-profits American Rivers and MountainTrue, is a two-pronged effort to restore the river’s water quality while creating better habitat for eastern hellbenders, whose populations have declined an estimated 70 percent since the 1980s. In the Watauga alone, scientists have noticed fewer young individuals, Adams says.

“We've seen a real decline in hellbender populations across the area,” says Andy Hill, who leads the Watauga Riverkeeper program for MountainTrue. “So it's really important to us to reclaim as much habitat as we have.”

The Watauga River winds through the cool, forested mountains of North Carolina and flows into eastern Tennessee. It’s ideal habitat for hellbenders, which need cold, clean, and heavily oxygenated water to thrive, Hill explains.

The rivers across southern Appalachia naturally flow fast, but as humans developed the area in the 1800s, dams were put in place to create reservoirs and power bygone industries like timber mills. In turn, water flow decreased, urban pollution increased, and sediment clogged up the crevices where hellbenders live and feed.

Sometimes nicknamed “snot otters” and “lasagna lizards” for their slimy, wrinkly skin, eastern hellbenders (Cryptobranchus alleganiensis alleganiensis) have beady eyes, muscular bodies, and can grow up to two and a half feet long. These large salamanders are important mid-range predators in the ecosystem, eating small prey like crayfish while feeding larger predators like trout, otters, and raccoons. Hellbenders are also highly sensitive to pollution because they breathe through the folds of their skin, which means pollutants and toxins more easily enter their bodies.

Restoring water quality, scientists say, is the key to protecting the salamanders and the rivers they inhabit.

Unclogging the rivers

Dam removals aren’t just happening on the Watauga. Across the country, defunct and unsafe dams are coming down to restore water quality, river flows, and fish migration patterns. The $700,000-project in North Carolina was partly funded through a larger $800-million allocation for dam removals nationwide from the federal 2021 Bipartisan Infrastructure Law. An estimated 540,000 dams exist across the country, according to the Southeast Aquatic Resources Partnership, with about 28,000 in North Carolina alone.  

Many of those dams no longer serve their original purpose. Shull’s Mill Dam was built in the early 1800s to power a timber mill, but the dam hasn’t operated since it breached in a 1940 flood. Breached dams are not only a safety concern, but the water flow is like spraying a hose with a nozzle straight into the ground, stirring up sediments, explained Erin McCombs, the Southeast conservation director at American Rivers.

Ward’s Mill Dam was the first dam removal on the Watauga in 2021. Eastern hellbenders hadn’t been documented near that dam in over 100 years, but they returned once it was removed. That got everyone thinking: “Can we keep working to reconnect the entire river basin?” McCombs says. “When you're able to remove that dam, it lets the river be a river again.”

You May Also Like

ANIMALS

Rare yet resilient salamander marks 16,000th species in Photo Ark project

ANIMALS

Love summer but hate pesky bugs? These predators are nature's pest control

ENVIRONMENT

What lurks beneath the surface of these forest pools? More than you can imagine.

To remove the dams, U.S. Fish and Wildlife construction crews rerouted a small portion of the river and used hydraulic hammers to take out the concrete and metal structures. Although it’s a messy process, the project leaders say the long-term benefits far outweigh the temporary disturbance.

As soon as a dam comes down, cold, oxygenated water rushes downstream. In response, fish swim upstream, river insects return, and hellbenders can stake out their historic territory.

“Removing dams is such an amazing tool for stream restoration because there's immediate and lasting benefit,” Hill says. “I think it's going to be utilized more and more in coming years, because dam removal’s kind of having a moment, certainly nationwide.”

(Read more: Hellbenders aren’t the only freshwater species under threat.)

Hell-bent on hellbenders

Scientists agree that restoring hellbender habitat is key to restoring populations.

Removing Shull’s Mill Dam has now reconnected 78 miles of the Watauga River. The team is also replanting the riverbanks with native vegetation—such as elderberry, silky dogwood and sycamore—to naturally filter stormwater and shade the river, keeping the habitat clean and cool.

“What’s happening with hellbenders here on the Watauga River is going to be good for hellbenders everywhere,” Hill says, adding that the relocation effort will help inform and inspire similar attempts elsewhere.

Eastern hellbenders live in rivers and streams across 15 states in Appalachia and parts of the Midwest, but the densest populations live in North Carolina, Virginia, Tennessee, and Georgia. Other populations haven’t fared as well.

Midwestern hellbender populations face a different set of threats — notably, more urbanization and agricultural runoff, creating siltation and hampering water quality. To preserve genetic diversity range-wide, it will be important to protect those populations too, says Rod Williams, a conservation biologist at Texas Tech University who studies hellbenders.

Williams previously led Purdue University’s pioneering wild “soft releases” of captive-reared hellbenders, a method the North Carolina team used. Soft releases allow the animals to acclimate to their new environment for a few days in an open cage resembling a lobster trap before they are finally released into the wild.  

On Indian Creek, a river in central Indiana, four dam removal projects are also underway to increase habitat and reintroduce eastern hellbenders by 2025, notes Williams.

The U.S. Fish and Wildlife Service will also reevaluate whether to add eastern hellbenders to the Endangered Species Act in December.   

As climate change continues to alter the environment, McCombs says, restoring existing habitat for hellbenders and other river-dwelling wildlife will become even more important. “With more severe drought and also more severe rain events and warming temperatures, I like to think a little bit about creating climate refugia: places for these species to be able to migrate,” McCombs says. “A dam is the end of the world for a lot of these species.”