Salamanders

Some of the content below is excerpted from the articles cited below and USGS and Penn State news releases.

As I’ve mentioned, my house sits on a bit over 10 acres, about three of them lawn and ornamental gardens which turned into baby deer and doe pasture this summer. The remaining seven acres is woodland, and much of the woodland is part of the “resource protected area,” RPA of the Chesapeake Bay. 

For a number of years, I have been engaged in a project to restore the woodland and cut back the invasive species. The invasive vines especially the autumn olive and Japanese honeysuckle were choking out the natural renewal process. As we’ve cut back the invasive species inside the woods, we’ve been creating a woodland path to walk  down the hill towards the creek. Now the path ends at a constantly muddy area where there is a seep above Chestnut Lick creating vernal pools in the spring. The area is drier during the summer in the past two years when we have had droughts. Still the soil remains moist.

A seep is the low-pressure twin of spring and occurs where groundwater discharges to the surface. In my case the groundwater emerges where the hill cuts down to the creek. Usually, seeps are merely wet , but groundwater discharge flows at many seeps even through the driest summer months. I was walking in the woods with an eight-year-old and trying to see if the August rains had restored the seep when I saw a red backed salamander. I had not seen a salamander since I was a kid and the eight-year-old and I were both excited.

Salamanders (Amphibia: Caudata) are ancient vertebrates. The red-backed salamanders is  a native of the northeastern United States especially in moist forest leaf litter, headwater streams, riparian ecotones, swamps, and seasonally inundated pools. Pretty much my back yard.

Now a new study cited below (with the longest list of authors I have ever seen) highlights the ecological niche of red-backed salamanders in the northeastern United States. The article found that the salamander’s population densities and biomass across the region was much higher than expected, with the greatest abundance in Appalachia.

The study authors estimated an average of 5,300 salamanders in every patch of forest the size of a football field (1.32 acres) in the Northeast. Even though each salamander is only3 inches long, the  number of red-backed salamanders means that they also have some of the highest biomass estimated for animals other than insects in the Northeast, similar to or greater than the biomass of the white-tailed deer. Wow.

“Salamanders serve a vital function in forest ecosystems,” explained David Miller, professor of wildlife ecology at Penn State and one of the co-authors of the study. “They are at the top of the food chain on the forest floor, where everything is breaking down into the soil that sustains this entire network of life. In fact, salamanders are so important to this life cycle that we can use them as a barometer for forest health.”

Just as I was thinking that seeing a salamander was a positive sign of the forest health, they gave me something new to worry over. A lethal invasive fungal disease.  Batrachochytrium salamandrivorans, or Bsal for short, is a fungal disease closely related to the chytrid fungus that is already devastating amphibian populations around the world. It was first found in the Netherlands in 2013 and, since then, has decimated the salamander populations in central Europe and continues to spread across Europe.

Bsal hasn’t been detected in the U.S. yet, so scientists and wildlife managers are preparing for its arrival with the North American Bsal Task Force. Another study completed this week tested proactive measures to see if they are effective. The Bsal Task Force needed evidence that proactive management would be more effective than waiting to respond until the disease is detected in the wild. So, Grant co-authored another recent paper that tested a series of proactive and reactive management actions to forecast the impact on salamander populations over time.

The study, “Proactive management outperforms reactive actions for wildlife disease control,” used computer modeling to confirm what seems intuitively obvious: namely, initiating management of wild populations before Bsal arrives is, in fact, more successful at keeping salamanders from disappearing than waiting until after Bsal is detected or not doing anything at all.

 “If we do nothing to manage Bsal, the model forecasted that the disease would be catastrophic to North American salamander species,” said Molly Bletz, assistant professor of disease ecology at Penn State and lead author of the second study. “This study gives strong quantitative support to proactive management actions." Basically, if we want salamanders to be around in the future, doing something besides wringing your hands.

 In addition, in 2016, the US Fish and Wildlife Service issued a rule that prohibits the importation or interstate transport of 201species of salamander and samples derived from them unless a permit is issued. It's a start. 

Grant Evan H. Campbell, Fleming Jillian, Bastiaans Elizabeth, Brand Adrianne B., Brooks Jacey L., Devlin Catherine, Epp Kristen, Evans Matt, Fisher-Reid M. Caitlin, Gratwicke Brian, Grayson Kristine L., Haydt Natalie T., Hernández-Pacheco Raisa, Hocking Daniel J., Hyde Amanda, Losito Michael, MacKnight Maisie G., Matlaga Tanya J. H.,  Mead Louise, Muñoz David, Peterman William, Puza Veronica, Shafer Charles, Sterrett Sean C. Sutherland Chris, Thompson Lily M., Warwick Alexa R., Wright Alexander D., Yurewicz Kerry and Miller David A. W. 2024Range-wide salamander densities reveal a key component of terrestrial vertebrate biomass in eastern North American forestsBiol. Lett.2020240033 Range-wide salamander densities reveal a key component of terrestrial vertebrate biomass in eastern North American forests | Biology Letters (royalsocietypublishing.org)

Davic, Robert D.; Welsh Jr., Hartwell H. 2004. On the ecological role of salamanders. Annu. Rev. Ecol. Syst., Vol. 35: 405-434

Salamanders are surprisingly abundant in Northeastern forests, study finds | Penn State University (psu.edu)

Molly C. Bletz, Evan H. Campbell Grant, Graziella DiRenzo; Quantitative support for the benefits of proactive management for wildlife disease control; First published: 26 August 2024. The Society for Conservation Biology (wiley.com)