Salamander Surveys at CWC Nature Preserves

Meet the Eastern Red-backed Salamander, Plethodon cinereus. This small woodland salamander is rarely seen, yet comprises a majority of the biomass of vertebrates in terrestrial ecosystems. Quite an impressive feat for a species that only weighs a few grams! Researchers are finding that this impressive density implies these salamanders play an integral role in the ecological health of the forest systems.

Eastern Red-backed Salamanders belong to the family of lungless salamanders known as Plethodontidae. Because these salamanders don’t have lungs, they breathe via cutaneous respiration (through the skin!) and gulping air. Lungless salamanders require a moist, mature forest habitat with ample leaf litter, which makes them a great indicator of ecological health.

Monitoring salamander populations can help us understand changes across the landscape and inform management plans. CWC established a study plot at Sylvan Solace Preserve in the spring of 2024 and began to collect initial count data later that fall. Soon after, we joined the Salamander Population and Adaptation Research Collaboration Network (SPARCnet). This regional initiative is designed to advance our understanding of environmental change on salamander ecology. Adjustments to our initial plot were made to meet the SPARCnet protocol, and an additional study site was placed at Hall’s Lake Natural Area. In 2025, CWC completed its first field season, collecting data.

The SPARCnet project focuses on the Eastern Red-backed Salamander, found in forests throughout the northeastern United States and into Canada. This regional collaborative network is designed to meet scientific and educational objectives associated with understanding the impacts of land use and climate change on salamander population dynamics.

While the abundance of the Eastern Red-backed Salamander has been documented previously (Burton and Likens, 1975), the SPARCnet project has updated population estimates and shed light on the importance of this species within the forest ecosystem. Grant et al (2024) estimated an average of 5,300 salamanders in every patch of forest the size of a football field in the Northeast. Even though each individual is a mere three inches long, the sheer number of salamanders indicates some of the highest biomass estimated for animals other than insects in the Northeast, similar to or greater than that of White-tailed Deer! While salamanders have many predators, they are at the top of the food chain on the forest floor. It’s safe to say that if these seldom-seen amphibians disappeared, there would likely be large consequences across the ecosystem.

CWC is currently collecting salamander count data at two study areas. Each plot consists of an array of 50 artificial coverboards arranged in a 5×10 meter grid. Untreated natural wood board is used to mimic the downed wood that salamanders seek for refuge. A minimum of three months prior to monitoring is needed for the boards to “season” and become attractive to the salamanders. However, we have found at our sites that additional time has been needed before occupancy is detected.

Three monitoring visits are conducted each spring and fall. Site covarities are documented, including start time, end time, sky code, wind code, air temperature, and soil temperature.  All the boards are carefully lifted and checked for salamanders. Each salamander is placed in a plastic bag and labeled with a board ID. They are held in a cooler to minimize stress. Once all the boards have been checked, we collect data on the salamanders. All individuals are processed on-site and returned to the boards where they were found. We hold a permit issued by the Michigan Department of Natural Resources (MDNR) to conduct these activities. Biosecurity measures are taken with the salamander’s safety in mind. Nitrile gloves are worn over clean hands free of any chemicals or lotions.

The salamanders are weighed, measured, and examined for sexual dimorphic characteristics with a technique called “candling.” By illuminating the salamander’s abdomen, you can see the eggs of gravid females or the testes and/or vas deferens of males. Male salamanders also have nasal protrusions called “cirri” that are visible by inspecting their faces, as shown below.

While only a single individual was found during spring survey efforts, seven salamanders of varying sex and age class were found in the fall. Was the lack of salamanders a result of drought conditions, or do they need more time to find the boards? Only time will tell. We have an idea of salamander abundance at each preserve from previous visual encounter surveys done by flipping natural cover objects. However, these were informal efforts with limited individual metrics documented apart from color phenotype and age class. This anecdotal information can be used to assess plot locations and help determine if they need to be moved. The salamander population data collected in the initial years of the SPARCnet project will serve as baseline numbers to help paint a picture of the overall forest health. The longer these surveys are conducted, the more insightful the data will become.

Now that the plots have been established, we look forward to expanding the project to include education opportunities. Last year, our intern, Avery, was able to participate in a monitoring visit during the spring. While no salamanders were found at the plot that day, Autumn located a nearby salamander under a log and demonstrated the processing steps. While we expect spring visits will be conducted by staff only, there will be limited opportunities available to assist during fall surveys. Keep an eye out for future communications on our usual media outlets for information on how to register.