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Researchers capture largest cave salamander in North America
Nicholas Gladstone had to crawl through a watery passage in a Tennessee cave to find the species he was looking for, but as it turned out, it found him first.
“I am usually recruited as the smaller person who can fit into the small cracks,” said Gladstone, a master’s student at the University of Tennessee-Knoxville. He climbed upstream through a small, wet area within the expansive cave system and awkwardly moved his head to maneuver through the tiny crevice.
“I turn around and there is this big behemoth before me,” he said. “I freaked out.”
Gladstone was helping capture and mark Berry Cave salamanders (Gyrinophilus gulolineatus), a species specifically adapted to live in caves that occupies only about 10 sites throughout eastern Tennessee, when the largest individual anyone had ever caught and recorded in North America appeared in front of him.
Usually, the team, which consisted of researchers from The University of Alabama in Huntsville and the University of Tennessee, would catch salamanders about the length of a pinky or index finger. This one measured in at about 8 inches — 5.7 inches without the tail. While this may seem small, this is one of the largest salamanders known from a cave. It might have been even longer, Gladstone said, but its tail was damaged, possibly from predation.
“We’ve seen them larger, but this is the one we could catch,” he said. The larger ones usually stay in deep pools, and when researchers shine a light on them, they quickly swim away never to be seen again. “It’s hard to catch these things in general and they almost always escape immediately,” he said. “I was fortunate to get to my senses and grab it quickly.”
Gladstone led the study published in Subterranean Biology, documenting the record-breaking individual. So far, researchers say, data on the species, which is a candidate for listing under the Endangered Species Act, is sparse.
“Unfortunately, we don’t have good data on how long individuals are living in populations, how fast-growing they are, their age structure, aspects of reproduction, survival — all metrics for a robust model to predict what happens to these populations in the future,” said Matthew Niemiller, an assistant professor at The University of Alabama in Huntsville and corresponding author on the study. “It’s tough to infer any type of trends for population declines or not with such limited data.”
He and his colleagues acquired funding from the U.S. Fish and Wildlife Service to survey the species and reassess their conservation status. The team was conducting mark-recapture studies when the discovery of the large salamander was made. They were going to the caves monthly to record data on the species.
The researchers plan to continue capturing the salamanders and recording data in an effort to create a model to help determine their status. So far, some things are already surprising them. “Preliminary data shows they’re growing much faster than we thought,” Niemiller said.
The study should help biologists better understand this species, which has evolved to live in areas without light, but it may also be important for their conservation.
“Cave systems are incredibly impacted by surface environmental runoff processes and their habitat can be destroyed with increased urbanization,” Gladstone said. “Understanding the way they live and how viable their populations are tells us more about where they are found, what needs to be prioritized and why.”