Capitol News

Michigan State University researchers contributed to a recent amphibian-focused study that highlighted the ecological importance of red-backed salamanders.

Scientists were aware that red-backed salamanders were abundant in eastern North America, but a recent study revealed their densities and biomass, or their total quantity across the region, were much higher than expected.

The study, conducted by the U.S. Geological Survey with contributions from Michigan State University and Penn State University, is the first to calculate the densities and biomass for this common but rarely seen species across its range.

The study authors estimated an average of 5,300 salamanders in every patch of forest the size of a football field in the Northeast. Despite each individual being only three inches long, the large number of red-backed salamanders means they have some of the highest biomass estimates for animals other than insects in the Northeast, comparable to or greater than white-tailed deer.

“The red-backed salamander, Plethodon cinereus, is a relatively common and small salamander,” said Louise Mead, a professor at MSU's College of Natural Science and Ecology, Evolution and Behavioral Program. “Given estimates of its density in forests across its range and extensive research already done on physiology, behavior, territoriality, and evolutionary history, the red-backed salamander provides a unique opportunity to study a small but mighty species further examining local adaptation and possible impacts of landscape and climate changes.”

The significant presence of red-backed salamanders captured in this study suggests that these amphibians play a more substantial role in terrestrial temperate ecosystems than previously thought.

“The very large biomass of red-backed salamanders tells us that they are likely ‘small but mighty’ in terms of their role in the ecological health of northeastern forests,” said Evan Grant, a research wildlife biologist at USGS and lead author on the paper. “If red-backed salamanders disappeared, there would probably be some pretty large ecosystem-level consequences.”

Many salamanders like the red-backed spend most of their time underground, making them easy to overlook. Grant refers to them as “hidden biodiversity” because they are often abundant yet well-hidden. Salamanders consume prey that larger animals cannot eat and serve as prey themselves for other animals, playing an essential role in an ecosystem’s food web.

“Salamanders serve a vital function in forest ecosystems,” explained David Miller, associate professor at Penn State and co-author of the study. “They are at the top of the food chain on the forest floor where everything breaks down into soil that sustains this entire network of life. In fact, we can use them as a barometer for forest health.”

However, just as scientists begin to understand their ecological importance better, a new wildlife disease poses a threat. Batrachochytrium salamandrivorans (Bsal) is a fungal disease related to chytrid fungus devastating amphibian populations worldwide since it was first found in 2013 in the Netherlands. Bsal has decimated central Europe's salamander populations and continues spreading.

Bsal has not been detected in the U.S., but scientists and wildlife managers are preparing for its potential arrival. The North American Bsal Task Force aims to limit invasion and reduce Bsal's impact in North America.

MSU’s involvement also provided opportunities for students.

“MSU joined SPARCnet (Salamander Population Adaptation Research Collaboration Network) in 2016; since 2017 students have been collecting data from six plots located at Rose Lake State Wildlife Research Area,” said Alexa Warwick, an assistant professor at MSU's College of Agriculture and Natural Resources. “We have integrated sampling into ecology labs taught by Mead engaging upwards of 200 students each year.”

Warwick also engages students in another project focused on mitigating disease spread through pet amphibian trade.

“With new understanding about how prevalent salamanders are within ecosystems alongside empirical justification for proactive management against threats like Bsal," said Bletz "it is more critical than ever to protect hidden biodiversity."

This research was recently published in Biology Letters.

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