News & Stories

A new paper by Kissel et al shows how complex life cycles interacting with climate change can lead to counter-intuitive outcomes for amphibian populations: https://doi.org/10.1016/j.ecochg.2023.100081

The first widescale assessment of methylmercury in adult amphibians in the U.S. shows that this toxic compound is common, widespread and, at least for some populations, can reach very high levels. The ARMI-led publication brought together scientists from around the country to test more than 3,200 amphibians representing 14 species from 26 populations. Amphibians are the most endangered group of vertebrates worldwide, but prior to this study, little information was available on mercury bioaccumulation in amphibians across the U.S.

Mercury is a contaminant of global concern that can harm humans and wildlife. In aquatic ecosystems, microbes can convert elemental mercury to methylmercury, which increases risks because methylmercury is more bioavailable, more toxic, and it biomagnifies through food webs.

Study results showed that the amount of methylmercury in amphibians varied widely among sites and by life history characteristics, such as diet, size, and sex. Amphibian methylmercury concentrations ranged from barely detectible at some locations, to levels above wildlife health benchmarks in others. The study also evaluated using dragonfly larvae to estimate bioaccumulation for amphibians that can’t be sampled because they are rare or secretive. Scientists determined that the concentration found in these insects can provide insight into methylmercury bioaccumulation in amphibians.

Despite its toxicity, scientists only have a limited understanding of methylmercury’s effects on amphibians and these results can be used to inform future research on the health effects of methylmercury exposure on amphibians. The study also provides new methods and baseline data that can help scientists and managers assess the risk from mercury for species of management concern, including species listed as threatened and endangered under the Endangered Species Act.

To view the full article click this link: https://pubs.acs.org/doi/10.1021/acs.est.3c05549

As first appeared in USGS NTK:

My late fall trek to Lost Lake in Rocky Mountain National Park to look for evidence of toad breeding is beautiful. The aspen leaves are golden. The air is downright cold at the 7 am start. The ten-mile hike starts downhill but soon angles up and continues up for the next eight miles. That is a lot of time to think about the end of another summer field season and about how few toads we observed. I can’t help but wonder if our field techs somehow overlooked breeding and egg masses? Or was it because it didn’t happen? It was only early October, but I settled in to a decidedly grim and early Halloween-edgy mood that was resistant to the bright blue of the sky and clung to me like a veil the rest of the hike.

Not a soul was camping at Lost Lake. The lake was still with only a few ravens providing their opinions on campers and, no doubt, toad conservation. All senses narrowed to look for a toadlet or an adult toad as I poked through the drying grasses and shrubs around the lake, and hopefully scanned the water’s edge. I could feel, more than see, the daylight dwindling.

On the far side of the lake I saw her, sitting on the shoreline. I stopped short as I saw the stiffness of her body and the blank white stare of her eye. The toad was dead. But hadn’t been dead long. I pulled out the “tools of the trade” and measured her, checked her for an identifying passive integrated transponder tag, and swabbed her to test for the amphibian chytrid fungus. She was not marked, and I only assumed she was a female based on size. I recorded a few bits of environmental data, and although firm-ish, the toad was in no condition to travel for further examination. I felt a chill and realized that the sun was completely gone. I left her on the shore with a quick prayer to the amphibian goddess and a furtive look around for moose.

Boreal toads, like the one I found, have been on the decline in Rocky Mountain National Park (RMNP), and the southern Rocky Mountain region for a while. One contributor to these declines is the amphibian chytrid fungus that thickens the skin, blocks osmosis (water intake), and eventually leads to heart attack and death. As a research zoologist, my colleagues and I have been working on amphibians in RMNP in northern Colorado for three decades. Our work ranges from questions of immediate interest to the National Park Service, like “how are the wood frogs doing with the hydrological changes on the west side of the park,” or “why are boreal toads declining” to overall management questions like, “what is the status of the amphibian species in the park and what factors may affect persistence?”

Although there are some bad days like my autumn hike to Lost Lake, there are glimmers of hope, or at least of gains in information that we might use towards amphibian conservation. We are currently working on a paper using three decades of data on chorus frogs, salamanders, and wood frogs in RMNP to examine changes in persistence over time across the landscape of the park. This work also considers a variety of mechanisms (e.g., visitor use) that may affect the probability of persistence and thus provides RMNP with information that can contribute to conservation decisions about the management of the park’s amphibians.

Erin Muths is a research zoologist at the Fort Collins Science Center and is a principle investigator for the Amphibian Research and Monitoring Initiative for the Ecosystems Mission Area. Her lab has studied boreal toads and other amphibians in the Rocky Mountains for more than 25 years. She is going to be sorcerer for Halloween.

As first appeared in USGS NTK:

First of all, newts are not the villains, instead, they are often the victims.

Newts are at risk, along with many animals, from climate change and from disease. In fact, they could be poster animals for climate change: In southern California, recent record warm air temperatures along with peak drought conditions are linked with a 20% reduction in mean body condition (e.g., mass) in the California newt (Taricha torosa)*. The disease Batrachochytrium salamadrivorans (Bsal, literally eater of salamanders in Latin) has caused significant devastation to salamander populations in Europe. This fungal disease affects primarily newts and salamanders and the Northeastern U.S. is considered the salamander capital of the world. While Bsal is not present in the United States now**, there is serious potential for the disease to spread from Europe to the U.S. through the pet trade***.

Second, newts are quiet neighbors that contribute to society.

For example, newts eat a variety of insects, and they are eaten by birds, snakes, and some mammals.

Third, newts appreciate Halloween and keep it alive all year!

Newts have three distinct developmental life stages that are in effect, costume changes! They begin as aquatic larva, metamorphose into terrestrial juveniles (sometimes called efts), then metamorphose into adults.

And finally, newts value their eyes.

If you are really looking for some eye of newt, go look in your local grocery, “eye of newt” is actually a very un-scary and easily acquired mustard seed.

Erin Muths is a research zoologist at the Fort Collins Science Center and is a principle investigator for the Amphibian Research and Monitoring Initiative for the Ecosystems Mission Area. Her lab has studied boreal toads and other amphibians in the Rocky Mountains for more than 25 years. She is going to be sorcerer for Halloween.

Michael Adams is a supervisory research ecologist at the Forest and Rangeland Ecosystem Science Center and is the Lead for the Amphibian Research and Monitoring Initiative for the Ecosystems Mission Area. His lab has studied newts and other amphibians in the Pacific Northwest for the past 25 years. His Halloween plans are a mystery to everyone including himself.

References:

*Bucciarelli, G.M., Clark, M.A., Delaney, K.S. et al. Amphibian responses in the aftermath of extreme climate events. Sci Rep 10, 3409 (2020). https://doi.org/10.1038/s41598-020-60122-2

**Waddle, J.H., Grear, D.A., Mosher, B.A., Grant, E.H.C., Adams, M.J., Backlin, A.R., Barichivich, W.J., Brand, A.B., Bucciarelli, G.M., Calhoun, D.L. and Chestnut, T., 2020. Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians. Scientific reports 10(1), p.13012.

***Connelly, P.J., Ross, N., Stringham, O.C. and Eskew, E.A., 2023. United States amphibian imports pose a disease risk to salamanders despite Lacey Act regulations. Communications Earth & Environment, 4(1), p.351.

Recent ARMI-led research showed the removal of invasive American bullfrogs from livestock ponds and small lakes in southern Arizona also resulted in the apparent local extirpation of two pathogens associated with the bullfrogs. The American bullfrog is native eastern North America but has become widespread in the West, where it preys on many native species of conservation concern. Other recent ARMI-led research from the area suggested that American Bullfrogs could act as reservoirs for pathogens like amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) and ranaviruses, which are often lethal to native amphibians, but less so to American Bullfrogs.

In the early 2000s, American bullfrogs were eradicated from ponds in the Buenos Aires National Wildlife Refuge near the Arizona-Mexico border to assist with the reintroduction efforts for the federally threatened Chiricahua Leopard Frog. In 2015, the bullfrog reinvaded the refuge and was once again removed. This reinvasion from outside the refuge motivated funding for a multi-year, landscape-scale eradication program. In the fall-winter of 2016 and the winter of 2020-2021, the research team tested the water at bullfrog eradication and control (no eradication efforts occurred) sites for the DNA (environmental DNA or eDNA) of invasive bullfrogs, federally threatened Chiricahua Leopard Frogs, and Bd and ranaviruses.

Results from the eDNA sampling showed American Bullfrogs were eradicated successfully from most sites, and where bullfrogs were eradicated, the pathogens were also no longer detected. Chiricahua Leopard Frogs did not increase in occurrence after eradicating bullfrogs, possibly due to an exceptional drought that could have limited the ability of native amphibians to colonize sites.

To our knowledge, this is one of the few studies to link eradication of an invasive species to co-eradication of emerging pathogens. Our spatially replicated experimental approach provides strong evidence that management of invasive species can simultaneously reduce predation and disease risk for imperiled species.

To view the full article click this link: https://doi.org/10.1111/conl.12970

Introduction: Designs for safe and effective road crossing structures for small animals are typically under-road microtunnels and culverts which have varying levels of effectiveness reported in the scientific literature. Many species, particularly migratory amphibians, may have limited ability to find and use passages if they are too far apart, resulting in substantial barrier effects.

Methods: We designed a novel open elevated passage (elevated road segment: ERS), similar to a low terrestrial bridge, that could theoretically be built to any length based upon species needs and movement characteristics. A 30 m length prototype ERS was installed along a forest road with a history of amphibian road mortality in Sierra National Forest, Fresno County, CA, USA. From 2018 to 2021, we monitored small animal activity under the ERS in relation to surrounding roadside and forest habitats using active infrared cameras.

Results: We documented a total of 8,815 unique use events, using species specific independence criteria, across 22 species of amphibians (3), reptiles (4), and small mammals (15). Poisson regression modeling of taxonomic group activity under the ERS, roadside and forest, showed that amphibian activity was highest in the forest habitat, no differences were observed for reptiles, and small mammal activity was highest under the ERS. However, mean activity estimates under the ERS were equal to or greater than the open roadside habitat for all 22 species, suggesting that adding cover objects, such as downed logs and vegetation may further enhance passage use.

Discussion: Overall, results showed that the design of the ERS crossing has potential to provide high connectivity for a wide range of amphibian, reptile, and small mammal species while reducing road mortality. ERS systems can also be used in areas with challenging terrain and other hydrological and environmental constraints. Incorporating current road ecology science, we provide supplemental ERS concept designs for secondary roads, primary roads and highways to help increase the options available for road mitigation planning for small animals.

To view the full article click this link: https://doi.org/10.3389/fevo.2023.1145322

This is one of many research studies USGS is conducting to inform safe and effective road crossing systems for amphibians and reptiles. See https://www.usgs.gov/centers/werc/science/reptile-and-amphibian-road-ecology for more information.

Amphibian Research and Monitoring Initiative (ARMI) scientists and Federal agency collaborators interacted with over a thousand visitors during Amphibian Week (Amphibian Week 2023 | PARC (parcplace.org) activities in Washington D.C. between May 5th and 8th. Evan Grant, Erin Muths, Kelly Smalling and Mike Adams organized the ARMI-hosted event on the National Mall on May 8th. This mini festival to celebrate amphibians, and amphibian science and conservation, included the U.S. Forest Service (USFS), the Bureau of Land Management, and the U.S. Fish and Wildlife Service in addition to the U.S. Geological Survey (USGS).

USGS Director David Applegate attended as did Shannon Estenoz, Assistant Secretary for Fish and Wildlife and Parks (Department of the Interior). Associate Deputy Chief Greg Smith and Deputy Director of Biological and Physical Resources Staff Debbie Pressman (USFS) also attended. The locally-sourced live amphibians were popular, as was Phil the Frog, who could be spotted roaming the Mall enjoying the spring day directing folks to the event (with his handler). Several hundred people walked by stopping to spin the trivia wheel, pick up some swag or look at the live amphibians.

The ARMI scientists also participated in Amphibian Week events earlier in the week. The week kicked off on May 6th with a U.S. Forest Service-led event at the Smithsonian Natural History Museum in the Q?rious learning space at the Coralyn W. Whitney Science Education Center with games, lots of amphibian information, and live amphibians from the local area. Nearly 500 people attended this event, playing the salamander migration game, find the frog in the leaf-litter and communing with Phil the Frog who danced his way around the event and around the Rotunda of the Museum, inviting more frog fans to the Q?rious space to help him celebrate Amphibian Week.

On May 7th there was a Smithsonian-sponsored event at the National Zoological Park. ARMI scientists pitched in with that as well, from cleaning exhibit windows, to running the spin-the-wheel trivia game and talking “amphibian” to zoo goers. The trivia game was wildly popular, as were the stickers! Several hundred people participated in this event in just the short 2-hours when ARMI was at the zoo. Phil the Frog had the day off but plans to participate at the zoo next year.

These activities were part of nation-wide efforts, led by Partners in Amphibian and Reptile Conservation (PARC), to bring attention to the plight of amphibians worldwide. These events provided an opportunity to support the message of Amphibian Week, but also to promote and showcase over two decades of science conducted throughout the U.S. by ARMI scientists.

Also in D.C., but on a more serious note, ARMI scientists were invited to visit several U.S. Representatives and Senators, as well as staff from the Congressional Research Service, to share amphibian science information and outcomes and listen to concerns about amphibians in their respective states. The Hill visits, which included our ambassador amphibians, were encouraging and the reception was incredibly positive with staff asking many interesting and insightful questions.

Phil the Frog thought it was an exhilarating and worthwhile week, but he is exhausted. Phil and the ARMI scientists want to thank a few of the myriad of folks who made this possible: Charlie Shafer, Jo Werba, and Adrianne Brand (USGS staff); Kerry Wixted (Association of Fish and Wildlife Agencies), Kim Winter (U.S. Forest Service), Efrain Tejada, Matt Evans and Brian Gratwicke (Smithsonian), Leslie Frattaroli and Mike Litterst (National Park Service), Michelle Christman (PARC), Darren and the staff at the hotel where we stayed, and USGS outreach staff, Suzanna Soileau, Sally House, and especially Michelle Collier who ran the show.

The USGS Amphibian Research and Monitoring initiative met at the Aquarium of the Pacific in Long Beach, CA, during November 1-3, 2022. ARMI researchers and collaborators met in a hybrid meeting to discuss a full suite of topics about amphibian conservation and how to provide the most useful information for managers. Discussions included updates on current regional projects, and the initial wrap up of a 5-year national research effort to look at relationships among disease, contaminants, and demography (e.g., survival). A major topic of the meeting was the identification and development of new efforts to address connections among climate change (current and predicted), and potential changes in range for species broadly distributed across the United States. Such work would include the identification and examination of a suite of landscape-level data such as wetland and pond dynamics, and incorporate other relevant data such as human footprint indices. The modular organization of ARMI makes it uniquely suited to address these and other landscape-scale questions because it facilitates the collection of field data, in a statistically robust manner, and across a broad swath of the country. This capability, paired with the quantitative know-how to effectively use those data, sets ARMI apart. Goals for this project include addressing particular hypotheses about species range and potential drivers of change and developing new continental-scale models that integrate landscape changes, especially in water dynamics. Ultimately, these models can be used to provide better and more easily updated predictions of the presence and persistence of amphibians and other species across the landscape informing management and conservation.

ARMI scientists Kelly Smalling, Evan Grant, Erin Muths, and Mike Adams will be in Washington, D.C. in May to promote Amphibian Week (Amphibian Week 2023 | PARC (parcplace.org)) and showcase efforts by the Amphibian Research and Monitoring Initiative (ARMI) to support amphibian conservation. Events range from field trips to see amphibians in the urban wild areas around D.C. to exhibits at the Smithsonian’s Natural History Museum and National Zoo, and a multi-federal agency amphibian festival on the National Mall. ARMI will provide coloring sheets and kid-friendly games and activities (e.g., test your knowledge and win a sticker at the trivia wheel, and practice some science techniques searching for the hidden biodiversity of the forest floor!). There will be visits from Phil the Frog and, at the Mall, live amphibians to view. Amphibian Week is sponsored by Partners in Amphibian and Reptile Conservation (PARC) and many other international agencies like the Amphibian Conservation Alliance. ARMI participates year around with PARC and other federal agencies on the amphibian week planning committee to designate events and develop themes and foci for each year’s amphibian week. This year themes include “Hidden Biodiversity”, “Amphibian Communication” and “Action for Amphibians”.

Here are the events happening in D.C. with highlights of ARMI participation:

Saturday, May 6:

The Coralyn W. Whitney Science Education Center (also known as Q?rius) at the Natural History Museum – Smithsonian (10 am – 12:30 pm) (The World and Me Family Program: Amphibian Week Celebration with the USDA Forest Service and Friends! | Smithsonian National Museum of Natural History (si.edu))

ARMI scientists will be there with several interactive stations, including the salamander migration game – a thrilling game of survival and chance! We will have several ways to learn about amphibians through trivia, coloring sheets, and stickers. As a bonus, Phil the Frog will be making a special guest appearance! The goal of this collaborative event, including the Smithsonian, USDA Forest Service, the Bureau of Land Management and US Geological Survey, is to bring the coolness of amphibians to the public and especially kids, through different stations that focus on the many fascinating characteristics of amphibians.

Sunday, May 7:

The Reptile Discovery Center at the National Zoological Park – Smithsonian (10 am – 12 pm) (Reptile Discovery Center Exhibit | Smithsonian's National Zoo (si.edu))

ARMI scientists will assist herpetologists from the National Zoo with an event highlighting amphibians and kicking off Amphibian Week. Activities will include a scavenger hunt through the Reptile Discovery Center, live amphibian demonstrations, the Appalachian salamander exhibit, and the opportunity to observe feeding time for resident Japanese giant salamander.

Monday, May 8:

Constitution Gardens, the National Mall (Maps - Constitution Gardens (U.S. National Park Service) (nps.gov)) (11 am – 5 pm). This multi-agency Amphibian Week event is hosted by the National Park Service. Agencies, including FWS, BLM, USDA FS, and USGS will be participating in a festival setting with different stations to learn about amphibians. In addition to the activities mentioned for the Q?rius event, ARMI scientists will be showing off a diversity of live amphibians. While these amphibians will be in aquariums, they will afford the public an opportunity to get up close and observe salamanders, frogs, and toads. Phil the Frog will be onsite.

Tuesday, May 9:

Chesapeake and Ohio Canal National Historical Park (Chesapeake & Ohio Canal National Historical Park (U.S. National Park Service) (nps.gov)) – Carderock Recreation Area

From 5:30 to 7:00 pm National Park Service and ARMI scientists will lead the public through a quick information session on amphibians (life cycles, migration, diversity and conservation). Live amphibians will be on view and we will visit multiple wetlands to talk about habitats, disease, the role of amphibians in the ecosystem, and biosecurity. As dusk comes to the park, we will guide the public through calling surveys and talk about the soundscape of this urban park and how it relates to amphibian behavior and persistence. Space is limited for this event and registration is required. Please use this form (https://forms.office.com/g/7eFNFPKiS1) to start your registration process.

A new collaborative study provided evidence that invasive, non-native American Bullfrogs influence the occurrence of native amphibians and increase occurrence of pathogens, including ranaviruses and amphibian chytrid fungus (Bd). These pathogens can cause lethal diseases of amphibians and have been linked with widespread population declines. ARMI scientists partnered with collaborators from Arizona Game and Fish Department, US Fish and Wildlife Service, Turner Endangered Species Fund, University of Arizona, Washington State University, and National Autonomous University of Mexico (UNAM) to analyze water samples from 233 sites in the southwestern USA and northern Sonora, Mexico, for the presence of environmental DNA (eDNA). Federally threatened Chiricahua Leopard Frogs and Western Tiger Salamanders were 8 times and 2 times, respectively, less likely to occur at sites where bullfrogs occurred. Ranaviruses were 10 times and Bd was 2.5-times more likely to be present at sites with bullfrogs than without bullfrogs. These results provide evidence that bullfrogs reduce occurrence of native amphibians and can increase occurrence of pathogens. This information can clarify risks for native species and aid in the prioritization of conservation actions.

Paper:

Hossack, B. R., E. B. Oja, A. Owens, D. Hall, C. Cobos, C. L. Crawford, C. S. Goldberg, S. Hedwall, P. E. Howell, J. Lemos-Espinal, S. MacVean, M. McCaffery, E. Muths, A. H. McCall, C. Mosley, B. H. Sigafus, M. J. Sredl, and J. C. Rorabaugh. 2023. Empirical evidence for effects of invasive American Bullfrogs on occurrence of native amphibians and emerging pathogens. Ecological Applications e2785. https://doi.org/10.1002/eap.2785