Group uses technology to track salamanders
LOUDONVILLE, Ohio — The group scanned the river, searching for signs of the slimy, dirt-colored salamanders from its muddy banks.
To actually see an elusive Eastern hellbender salamander, though, they’d have to flip the large, flat boulders that shield their underwater living spaces and plunge into the murky water of the Mohican River.
The process is labor-intensive and unlikely to yield results in areas where the state-endangered salamanders haven’t been spotted before.
But a new tool that tests water for tiny traces of animal DNA can help researchers figure out if they’re on the right track before they begin searching. The emerging science is called environmental DNA, or “eDNA” for short. Earlier this month, a team from The Wilds piloted a new kind of equipment that transforms a smartphone into an on-site eDNA detector to determine if a particular animal has recently been living in a waterway.
The Wilds folks will compare results with traditional lab tests conducted on larger, more complex equipment to see if they’re similar and to verify the accuracy of the new methodology. They’re testing multiple sites this month in the Muskingum River watershed.
“It’s cool, real-time technology for folks who maybe don’t have a lab, or who have a narrow time frame to evaluate multiple sites,” said Stephen Spear, director of wildlife ecology at The Wilds. “If they get a positive test, they can get right in the river and go do it.”
While water samples are mostly tested for eDNA in labs, it can be challenging when those labs are located far from the bodies of water being examined.
That’s the case for The Wilds, a 10,000-acre wildlife conservation center that the Columbus Zoo and Aquarium operates about 70 miles southeast of Columbus. Zoo staff members and other wildlife activists across Ohio have released hundreds of hand-reared hellbender salamanders into the state’s waterways since 2012, hoping to reintroduce the species in areas where human impact has reduced their populations to near-extinction.
But surveying past or potential release sites requires some planning, especially when time and heat can degrade DNA before it gets back to their lab.
The “two3” technology tested recently could eliminate those obstacles. Biomeme, a Philadelphia-based company, makes the device, a one-pound box that attaches to a smartphone, which acts as an interface to run the test and send results to a digital storage cloud.
It costs about $4,000, according to Biomeme’s website.
That’s just a fraction of the cost of machines in traditional labs, but the affordability and convenience still comes with some trade-offs, Spear said. The two3 can only run three samples at a time, for example, while a traditional lab can test nearly 100 at once. That test takes longer, though. The lab tests also typically use a mechanical centrifuge to filter the water.
The Wilds field group experienced a limitation related to that variation.
Its members readied a water sample for testing by sending it through a hand-pumped filtration system, syringes and substances used to wash off unwanted materials and capture any potential DNA on a filter. That process took almost as long as the 50-minute DNA test itself.
Yet the tests still came back inconclusive because of organic matter in the water that muddied the results.
Spear ended up taking the water back to the lab anyway to spin it in a centrifuge and clean it more. He learned the Mohican River site had officially tested negative for the presence of hellbenders.
Amelia Tomi, 26, of Ashville, an intern at The Wilds who helped with the tests, said it was encouraging to receive the results without trudging through the riverbed.
“It’s a way to create awareness without destruction of habitat,” Tomi said.
Tomi is also studying eDNA in controlled environments during her internship with The Wilds, including testing whether the DNA of other species of salamanders can be detected in soil.
As the technology continues to advance, Spear said he hopes it someday can detect more than just an animal’s presence. A test that confirms the number of animals present, or even tracks their unique genetic makeup, would be beneficial for monitoring a population’s overall health, he said.
A river with just one hellbender living in it, for example, wouldn’t be nearly as exciting a discovery as a river with dozens.
And a river with young hellbenders would be the most thrilling find yet. While researchers can find hellbender eggs and adults, they’re still struggling to find juveniles — a puzzle they’ve yet to solve, said John Navarro, the aquatic diversity program administrator for the Ohio Department of Natural Resources Division of Wildlife.
Though eDNA hasn’t advanced that far, Navarro has faith it could.
Navarro’s department is already using it to detect invasive species, including troublesome Asian carp. The Ohio Department of Transportation has used it to survey streams prior to bridge construction or repairs, to ensure that rare species, such as freshwater mussels, aren’t disturbed, he said.
“The technology is moving so fast, it’ll make your head spin,” Navarro said. “When it comes to the world of rare animals, it’s really breakthrough science. It’s only going to get better and better.”