Research Brief: Salt tolerance in spotted salamanders

Spotted Salamander in a tidepool.

Courtesy of Dr. Steve Ressel

Steve Ressel, College of the Atlantic

What does your research hope to answer/investigate?

This project seeks to better understand how amphibians are able to cope with exposure to environmental salt, an environmental stressor that has long thought to be detrimental if not fatal to nearly all amphibians. In the Spotted Salamander population I am studying, individuals migrate to breeding pools close to the ocean's edge in spring, a highly atypical breeding habitat for this species. While there, individuals are exposed to salt spray and occasionally tidal surges associated with coastal storms. Whether this population is locally adapted to salt or not is the core question of my research.

Please describe your process for investigation? Are there clear stages or benchmarks that your research project will have along the way?

For the past seven years, I have been measuring salinity levels in the coastal breeding pools to document the extent to which salinity increases over inland freshwater pools that are usually used by Spotted Salamanders in the spring. I am also marking animals with a harmless fluorescent tag to study whether the same salamanders breed at this coastal site from year to year. In addition, I am measuring salt tolerance in coastal breeding salamanders vs inland freshwater breeding salamanders by examining and comparing salt concentrations in their blood and by observing how individual animals respond behaviorally to increased salt in their water; that is, do they flee experimentally altered water or not?

How does this research apply to what we might know about or how we might manage Acadia National Park?

This research holds promise to assist park biologists in their on-going efforts to determine the range of habitats used by the herpetofauna found within the park, and how these vertebrates may be impacted by rising sea levels.

How does this project help contribute to scientific understanding or management solutions beyond Acadia?

This research holds promise to assist park biologists in their on-going efforts to determine the range of habitats used by the herpetofauna found within the park, and how these vertebrates may be impacted by rising sea levels.