wpengineViews:
David Hutto, Jr., has been a member of The Orianne Society since 2015. This summer, he spent time working with the United States Geological Survey and writes about his experience working to conserve amphibians in this guest article.
Authored by David Hutto, Jr.
Crawling through streams, wading in wetlands, hiking for miles over mountain ranges in a variety of weather conditions—this is pretty much where the similarities between the ARMI and the branch of the military with a similar name end. The Northeast Amphibian Research and Monitoring Initiative (NEARMI), is a division of the United States Geological Survey based out of the Patuxent Wildlife Research Center in Laurel, MD. This summer I had the opportunity to work for NEARMI conducting hands on work with amphibians throughout Maryland, Virginia, West Virginia and the District of Columbia area.
As many well know, amphibians are being threatened by habitat loss and degradation, changing climates, and disease. Ranavirus and two strains of chytrid fungus—(brace yourself for these names): batrachochytrium dendrobatidis (Bd) and batrachochytrium salamandrovirans (Bsal)—are devastating diseases that are either currently affecting or have the potential to affect amphibian populations in North America. Ranavirus is a virus that affects the host internally causing hemorrhaging and lethargy, whereas both strands of chytrid are funguses that take advantage of and grow within the moist, semipermeable skin of amphibians affecting their abilities to breathe and osmoregulate. Ranavirus and Bd have both been reported in wild U.S. populations of frogs and salamanders while Bsal currently only exists in captive salamanders within the U.S., although it is widespread and devastating in wild European salamander populations. In order to test for and monitor these diseases, scientists must sample wild populations of amphibians through “boots-on-the-ground” research, and this is where my work comes in!
Strapping on muck boots and chest waders and grabbing long-handled dip nets allowed us to capture tadpoles and larval salamanders that could be processed and sampled for disease occurrence. Vernal pools (those pools that only hold water for a few months out of the year, typically in the spring) were the main focus of our surveys because they serve as hot spot locations for frogs and salamanders to breed somewhat safely and to deposit eggs without the threat of fish or other predators that may be present in more permanent wetlands. We made note of all species that we caught, but three species were targeted for disease sampling: Wood Frogs (Lithobates sylvaticus), Spotted Salamanders (Ambystoma maculatum) and Eastern Red-spotted Newts (Notophthalmus viridescens). We attempted to capture at least 12 individuals of these species at each pool (providing the species were present) to give us a large enough sample size to send to the laboratory. To test for Bd each species is swabbed at the individual areas where the fungus congregates. Wood Frog tadpoles were swabbed at the mouthparts, and Spotted Salamander larvae were swabbed at each armpit, base of the legs and their vent. A small tail clipping was taken from each individual, ensuring that a significant amount of musculature was obtained in order to test for ranavirus.
The potential for these diseases to spread within wild populations is very high, especially when taking into account human factors such as the release of captive amphibians, movement for pet trade and even the use of amphibians as fishing bait (ranavirus has also been documented to affect turtles and other reptiles). According to my supervisor, Andrew Dietrich, in Maryland’s Patuxent Wildlife Refuge alone, approximately 40 percent of pools have tested positive for ranavirus, with nearly 20 percent of pools testing positive for Bd. As for Bsal, this fungus only affects salamanders, including newts, so in addition to searching vernal pools, we also surveyed streams for these enduring creatures. Newts have been found to be highly susceptible to Bsal, with those affected having extremely high mortality rates in lab tests making them the perfect candidate to test for this deadly fungus. By swabbing adults under each arm, leg and vent, we were able to gather samples that could be tested. Hopefully we can keep a leg up on this catastrophic disease so that it does not become a widespread problem in North American populations. We certainly don’t want to list more salamander species as Endangered.
A change of location is needed to set the stage for the next bit of research conducted with the NEARMI crew. In order to carry out this new work, I had to tap into my inner mountain goat as I scrabbled up and down talus, rocky slopes in search of a small terrestrial salamander. The setting: Shenandoah National Park. The species: the endangered Shenandoah Salamander (Plethodon shenandoah). These interesting little fellows only live on three mountain peaks within the park: Hawksbill, Pinnacle and Stony Man. They primarily inhabit moist microhabitats in the drier, talus areas that Red-backed salamanders (Plethodon cinereus) seem to find unsuitable. Their competition with Red-backs, which limits their range to these drier, somewhat cooler habitats, along with potential threats within their defined population appear to be the cause of their endangered status. Introduced insect pests that lead to an increase in tree defoliation, human use of the park and climate change, which could lead to higher temperatures than the species can handle, are additional threats facing the Shenandoah Salamander.
NEARMI has partnered with the National Park Service to provide better descriptions of the species’ range and overall abundance in an effort to better manage their habitat and minimize local human impacts. All Shenandoah and Red-backed Salamanders that were caught were identified to species (they look identical to the untrained eye), measured, sexed, assigned a ventral and dorsal stripe code, and released. I will spare you the details of setting up transects on each mountain peak, however field techs risked twisted ankles, broken bones and other injuries (including 13 stitches and a broken finger that is still healing as I type this) all in the name of science.
This past summer was a blast, and I had the experience of a lifetime getting up close and personal with some very interesting species. I am proud to say that the work I was able to put in is being used to further the understanding of these animals and the troubles that they face so that we may learn how to better manage the resources we have left. As long as we have biologists, boots-on-the-ground technicians and people in the lab willing to put in the work and fight for our species and natural resources, we have hope.
