11 july 2014

The largest salamander in the U.S. is vanishing and scientists are perplexed as to the reason why.

The hellbender— the largest salamander in North America— is vanishing and scientists do not know the reason why.

Hellbenders, also known as snot otters and devil dogs, can grow to more than two feet long and inhabit 16 states in the eastern U. S., including New York, Indiana, Arkansas, and North Carolina. In 2011, the Ozark hellbender— found only in Missouri and Arkansas- was put on the federal endangered species list after populations declined some 75 percent.

Scientists think the demise of the hellbender, which makes its home in streams and rivers, could be a result of declining water quality.

“These are animals that live up to 30 years in the wild, so if you have populations declining, that alerts us that there could be a problem with water quality,” said Rod Williams, an associate professor of herpetology at Purdue University, in a report by the Associated Press (AP). Because hellbenders breathe almost entirely through their skin, they are a living barometer of water quality, Williams said. He has been monitoring Indiana’s hellbenders for almost ten years.

Along with water contamination, scientists believe other factors could be contributing to the salamander’s decline. They point to dams, which slow down the swift currents this amphibian prefers, and development, which produces sediment runoff that fills the rocky nooks hellbenders use for shelter, the AP reported.

Because of the hellbender’s long life span, researchers were late to recognize the rate at which their numbers were dropping, the U.S. Fish and Wildlife Service (USFWS) said in a statement. Even in areas believed to have stable populations, the salamander’s numbers have plummeted. In addition, most populations contain mostly older individuals, showing that the rate of reproduction has been slowing drastically in recent years.

In an effort to boost the hellbender’s numbers, landowners are being encouraged to plant grasses and trees along river banks to improve water quality. Researchers also are raising hellbender babies to be released into the wild.

Source: http://www.sciencerecorder.com/news/salamander-disappearance-baffles-scientists/