Measuring impact of road salt on species

Team studying frogs, other amphibians for adapations

NEW HAVEN — As springtime begins in earnest, many residents in Connecticut have shelved their memories of the winter’s nor’easters.

For the wood frogs and spotted salamanders that live in vernal pools along the state’s roadsides, however, the runoff of winter road salt may be leaving an imprint on the future of the species.

To investigate this, Steven Brady, an assistant professor of biology at Southern Connecticut State University, researches how ecology mixes with evolutionary biology to find out how wildlife is adapting to environmental change.

“It’s one change in the landscape, but it brings a suite of effects,” he said.

Brady said not much research has been done on the evolutionary and adaptive impact road salt can have on roadside populations, but it’s possible the populations of these pools will begin to feature more saltfriendly species, or that wood frogs or salamanders may be endangered if its strongest jumpers have a lower rate of survival because of the salt.

Under Brady’s guidance, pre-med student Lauren Frymus and sophomore Faruk Senturk are running an experiment at the university to measure the impact salinity has on wood frog tadpoles, by raising the eggs in tanks with variable salinity. Senturk, who is interested in conservation biology and ecology, applied for

and received an undergraduate research grant to support his work in the lab.

Although the survival rate of tadpoles in high salinity is lower and the team has observed some mutations such as crooked spines, Frymus said the team has been surprised at how resilient some of the subjects have been.

A study co-led by scientists from Yale University and Rensselaer Polytechnic Institute, the results of which were released in 2016, found, among other results, that road salt makes the frog population more masculine. Male tadpole populations increased 10 percent when exposed to the salt, the release on that study said.

“The health and abundance of females is obviously critical for the sus- tainability of any population because they’re the ones that make the babies. So if you have a population that is becoming malebased, the population might be at risk,” the Yale/ RPI 2016 release said.

Brady said his initial concept for the experiment was to measure the growth and resiliency of wood frog tadpoles in salty water, but the students have collected data at the same level as doctoral students.

“As an undergrad, this is a lot of work,” Senturk said.

Frymus said the two are nearly constantly in the lab while also balancing a regular load of classes.

Brady said the convergence of evolutionary biology and ecology is a fairly recent development to both fields, although he concludes it makes sense to consider the relationship between competition and evolutionary adaptation.

With the reproductive schedule of wood frogs, Brady said, often times they begin to mate at the same moment vernal pools are at peak saltiness, sometimes including unnaturally warm days after a snowstorm.

The danger for the species, he said, is that frogs that make habitats in roadside pools are typically evolved from the farthest jumpers, as they must survive among road traffic. If salt in the water were to impairthe development or survival rate of some of the farthest jumpers in the species, it could have a deleterious effect on the entire species.

An alternative theory he has is that salty pools are already an “island of misfit toys,” where the weakest in the offspring are dumped, meaning the species as a whole could go farther into the woods.

Although the SCSU team has begun the work, Brady said it would be too soon to make conclusions about the impact road salt can have on amphibians when it reaches their mating habitat until the cycle has occurred several times.

“The health and abundance of females is obviously critical for the sustainability of any population because they’re the ones that make the babies. So if you have a population that is becoming male-based, the population might be at risk.”

2016 study by Yale/Rensselaer Polytechnic Institute

Peter Hvizdak / Hearst Connecticut Media Southern Connecticut State University professor Steven Brady shows a preserved spotted salamander. With him are students Faruk Senturk, left, and Lauren Frymus.