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Tennessee Wildlife Resources Agency
Ellington Agricultural Center
440 Hogan Road
Nashville, TN 37220
(615) 781-6500
Assessing the Status of Green Salamanders in Tennessee and Beyond

The Green Salamander (Aneides aeneus) is a cryptic species of lungless salamander that is rarely encountered in Tennessee. The species is a habitat specialist whose primary habitat is along sandstone rock outcroppings where they are found inside of narrow crevices. The species is occasionally found on limestone outcroppings and, more infrequently still, under logs and in trees.

This is the only species of salamander in eastern Northern America that has a green coloration, which makes excellent camouflage around the moss-covered, shady rock outcroppings it calls home. The coloration is an excellent adaption to conceal Green Salamanders from predators and researchers alike!

When a species is declining . . .

Unfortunately, Green Salamanders face a variety of anthropogenic threats and, overall, the species is thought to be declining across its range. Disease caused by the Chytrid fungus and Ranavirus are leading to mass extinctions of amphibian species across the world, and both diseases have been found in the Green Salamander. While disease is certainly a major threat, habitat loss and fragmentation is likely the greatest threat to amphibians, including the Green Salamander. Threats to habitat can isolate populations and inhibit the flow of genes which can lead to dramatic population declines.

In 2012, the U.S. Fish and Wildlife Service was petitioned to protect the Green Salamander under the Endangered Species Act. After an extensive review process, the U.S. Fish and Wildlife Service announced in 2015 that protection may be warranted. To make an accurate assessment of the species’ conservation status, knowledge gaps concerning many aspects of its demographics (population size, natural birth and death rates) and ecology must first be filled.

Research to fill knowledge gaps begins . . .

To fill these knowledge gaps, the Tennessee Wildlife Resources Agency (TWRA), in partnership with five other states representing the core of Green Salamander geographic distribution, applied for and received a competitive State Wildlife Grant from the U.S. Fish and Wildlife Service. The three primary objectives of the research are to: 1) survey historical occurrence records and document new occurrences of the species, 2) assess the prevalence of disease, and 3) evaluate the genetic structure of the species across its range. The TWRA then partnered with the University of Tennessee at Knoxville to conduct the disease aspect of the study and with the University of Alabama at Huntsville to conduct the genetic analyses.

During the spring and summer of 2018, TWRA biologists and their university partners surveyed numerous areas across the eastern two-thirds of the state including Wildlife Management Areas (WMAs), State Parks, State Natural Areas, State Forests, and private lands in search of the elusive Green Salamander. The basic method for finding the species involves walking along bluff lines and rock outcroppings, and peering into crevices with flashlights.

Once an individual is found, researchers use zip ties to coerce the salamanders out of the crevice and into a single use zip-lock bag. While in the bag, measurements are taken along with swab samples that will be sent to the University of Tennessee for disease testing. Also, a small section of the end of the tail is severed off for genetic sequencing at the University of Alabama. Finally, the salamanders are released back into their crevice.

Promising results begin coming in . . .

The research is ongoing, but the initial results of the first objective are promising. For example, prior to the initiation of this study, TWRA had seven occurrence records of Green Salamanders on Bear Hollow Mountain Wildlife Management Area in Franklin County, Tennessee. After searching transects along sandstone bluff lines for about 16 hours total over several months, we now have 61 new occurrences on Bear Hollow Mountain and many other potential areas to search. Green Salamanders were found in all but 3 of the areas that were searched on Bear Hollow Mountain.

A similar result is unfolding further north along the Cumberland Plateau. Prior to the initiation of this project, only one individual Green Salamander had been documented at Bridgestone-Firestone WMA in White County, Tennessee despite the area having some ideal habitat features. After searching transects for approximately 6 days over the summer, the TWRA now has 24 new occurrence records and, like Bear Hollow Mountain WMA, there are many, many more miles of bluff line to be surveyed.

New occurrences for Green Salamanders have not been limited to the Cumberland Plateau. Prior to this research only one record existed for Chuck Swann WMA in the Ridge and Valley physiographic region. Through efforts associated with this competitive state wildlife grant program, four additional records have been documented on the WMA. Also, four new occurrences were documented over the summer at North Cumberland WMA in the Cumberland Mountains physiographic region.

A pattern appears to be emerging with these surveys, and the results are surprising. Green salamanders are hard to find, for sure, but they are indeed present in most of the areas that have been searched. Moving forward with a better mental search image, researchers are optimistic that new occurrences will continue to be found.

Next step: designating monitoring sites . . .

The next step for TWRA biologists, in addition to searching for new occurrences, is to designate areas with relatively abundant populations as monitoring sites. In much the same way that individual zebras can be identified by the pattern of their stripes, green salamander individuals can be identified by the pattern of green blotches on their bodies.

Dr. Kevin Hamed at Virginia Highlands Community College found that by comparing photos of green salamanders from one trapping event with photos from subsequent trapping events, individuals can be reliably identified. This allows using a mark and recapture style monitoring program (which will identify but not actually mark the salamanders) to begin assessing the population size of a certain area, the survival rate, and the recruitment of juveniles to adulthood. This demographic information is critical to assessing the health of the species’ populations.

Ultimately, protecting a species under the Endangered Species Act is a costly and time consuming endeavor, and the primary goal of the State Wildlife Grant Program is to provide research that will keep species from being listed unless protection is absolutely critical. At the conclusion of this research, we will have a much better idea of how disease is impacting Green Salamanders across their range and if populations are being isolated enough to halt gene flow across populations. The fact that new occurrences are being found across the state is promising and it leaves us cautiously optimistic that populations are stable.

As the other objects of this research are fulfilled, we will be in a much better position to not only assess the conservation needs of Green Salamanders, but also focus our conservation strategies to best ensure the persistence of these colorful amphibians for generations to come.

View or download an illustrated Green Salamander factsheet with photos.

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