News & Stories
ARMI researchers work on innovative projects throughout the country. News & Stories offer insight into the work of wildlife biologists and the issues facing our nation's amphibians. Explore our site for news & stories about our latest research and how it's used in the management of wildlife and their habitats.
USGS neither sponsors nor endorses non-USGS web sites; per requirement "3.4.1 Prohibition of Commercial Endorsement."
News & Stories Race to save rare California frog beats coronavirus lockdown
Full article is available here: www.latimes.com/environment/story/2020-04-09/scientists-beat-coronavirus-lockdown-to-save-rare-california-frog
The official press release by the The San Diego Natural History Museum also covers this project (in which they play an important role): www.sdnhm.org/pressroom/pressroom_details/california-red-legged-frogs-returned-to-historic-range-in-southern-california/37/
We also earned a spot on the USGS Facebook page which can be seen here: www.facebook.com/USGeologicalSurvey/posts/3034689379910358
You can find the search tool here: doi.org/10.5066/P9GGPPF7
News & Stories Honoring the late Gary Fellers
Dr. Fellers was one of the Principal Investigators for ARMI. To download his obituary that was published in Herpetological Review, please visit: armi.usgs.gov/docs/Gary_Fellers_obit_in_HR.pdf
News & Stories ARMI scientist Michael Adams receives 2020 PARC honor
This award recognizes individuals in North America who exemplify extraordinary commitment to herpetofaunal conservation. The PARC Joint National Steering Committee (JNSC) was impressed with the multitude of examples that spanned local to global partnerships affecting international conservation efforts, such as serving as the Surveillance/Monitoring lead on the Bsal Task Force.
“Your ability to connect people and science at multiple levels and to facilitate key partnerships while providing rigorous science to meet local, regional, national, and international management needs in the field of amphibian ecology and conservation is indeed striking,” the JNSC letter stated.
In addition, Mike’s leadership and behind the scenes work as National Coordinator for the USGS Amphibian Research and Monitoring Initiative has been recognized as the sustaining force behind the national program, a program of excellence in science and conservation that is unparalleled by any other federal government effort and is a model for other nations.
Mike’s outstanding passion for, and dedication to, conservation of amphibians and reptiles was recognized by the JNSC through, “...your leadership, science, and collaborations. Your contributions to herpetofaunal conservation exemplifies all of our Core Values: Collaboration; Proactive Approaches; Scientific Integrity; Value in All Biodiversity; and Maintaining Optimism and fits our desire to acknowledge "unsung heroes" in herpetofaunal conservation.”
Mike will receive the award on March 20, 2020 at the North American Wildlife and Natural Resources Conference in Omaha, Nebraska.
News & Stories ARMI in the news - Recovery: Saving Mark Twain’s Famous Frog
The main character of Mark Twain’s first literary success, The Celebrated Jumping Frog of Calaveras County, was a California red-legged frog whose noted leaping ability was annulled by birdshot surreptitiously forced down its throat.
When The New York Saturday Press ran the story on November 18, 1865 California red-legged frogs were so abundant in and near the state’s coastal areas they provided a booming market for frog legs.
Today the West’s largest native frog is missing from 70 percent of its historic range and listed as federally threatened. Likely causes include an alien amphibian disease called chytrid fungus, development, urban runoff, water loss from diversions, drought and fire from climate change, past predation by humans and current predation by non-native fauna.
But recovery efforts by multiple partners, including The Nature Conservancy, are producing spectacular results.
View full article: blog.nature.org/science/2019/11/14/recovery-saving-mark-twains-famous-frog/
News & Stories ARMI scientists participate in International Symposium: Amphibian population declines – 30 years of progress in confronting a complex problem. Montreal, Canada
population declines, the Redpath Museum and McGill University in Montreal held an international symposium on amphibian ecology and conservation biology to bring together many of the principle researchers now making significant advances in the field. Evan Grant and Erin Muths, Principle Investigators for ARMI, were invited participants to the symposium held in September. Dr. Grant presented a lecture on lessons from broad-scale synthetic analyses about drivers of decline and Dr. Muths presented on the effects of disease, temperature, and community on demography and how analytical advances allow us to address more complex questions about decline. Both topics will be
featured manuscripts in the forthcoming special issue of the journal Herpetologica.
News & Stories Monterey salamander finding at San Diego National Wildlife Refuge prompts biologists to test for deadly fungus
Robert Fisher from the U.S. Geological Survey is one of those reptile experts, known as herpetologists. On a hunch and from his extensive knowledge of amphibians in Southern California, he set out in early February with a small team of biologists in search of a specific species; located in a closed area of the San Diego National Wildlife Refuge.
Fisher predicted that with the unique soil and plant types found on San Miguel Mountain, along with its higher elevation and longer exposure to moisture in the air, he might find the species he had in mind: the Monterey salamander (Ensatina eschscholtzii eschscholtzii). Then if any were found, they would come back to collect tissue samples to test for a deadly fungus specific to salamanders, called chytrid fungus.
Full text: www.fws.gov/cno/newsroom/highlights/2019/monterey_salamander/
News & Stories Exploring the amphibian exposome in an agricultural landscape using telemetry and passive sampling
Full article is available here: www.nature.com/articles/s41598-018-28132-3
News & Stories Invasive crayfish wreck havoc on amphibians in southern California, and now its clear they also increase mosquito larvae.
News & Stories 1000 Critically Endangered Mountain Yellow-legged Frogs released back into Los Angeles County!
Los Angeles Times news story at this link: www.latimes.com/local/california/la-me-rare-frog-release-20180627-story.html
Although most of the public associates vehicle strikes with mammals, reptiles and amphibians can also encounter cars on the road. These animals are often either too small for the driver to notice, or too slow to escape the car?s path. Some species also migrate long distances or have relatively large territories, and may need to risk crossing a roadway to access important habitat. Some species avoid roads altogether, which potentially reduces the amount of available habitat and separates populations that would otherwise mix and increase genetic diversity.
Currently, transportation planning agencies like the California Department of Transportation (Caltrans) use underpasses, overpasses, and physical barriers to reduce the negative effects of roadways on wildlife. However, they can?t manage these side-effects for every species because of limited funding or resources. Species at highest risk of negative road impacts are difficult to identify due to a lack of available data or research, particularly on reptiles and amphibians. As a result, resource managers had to identify high risk species by professional opinion or by the few studies related specifically to roads.
To help provide Caltrans and other transportation agencies with the information needed to prioritize species for management, USGS researchers used road ecology literature to develop an objective ranking system for 166 species and subspecies of native Californian reptiles and amphibians. In the ranking system, an animal?s vulnerability to vehicle strikes or habitat fragmentation depended on the way members of the species used the space around them, and on different aspects of their life history. For instance, species with large home ranges and seasonal migrations were more likely to encounter roads. Likewise, species that took time to reach sexual maturity and had fewer young were more likely to be affected by the loss of members of their population from vehicle strikes.
The scientists found that all turtle and tortoise species, 72% of snakes, 50% of frogs and toads, 18% of lizards, and 17% of salamander species in California ranked at ?high? or ?very high? risk from potential negative road impacts. Species at very high risk included listed Federal or State endangered or threatened species, like the California red-legged frog (Rana draytonii), Mohave desert tortoise (Gopherus agassizii), and the San Francisco gartersnake (Thamnophis sirtalis tetrataenia). Snakes, turtles, and tortoises tended to rank at higher risk for negative road impacts, since many migrate or have large home ranges, tend not to avoid roads, are long lived, and give birth to relatively few young.
Species that use both terrestrial and aquatic habitats may be particularly susceptible to reduced habitat connectivity. The giant gartersnake (Thamnophis gigas), for example, is a semi-aquatic species found in the Central Valley of California. After losing more than 90% of its historical wetland habitats to agriculture and other forms of human development, this federally and state-listed snake now relies on remaining wetlands, rice fields, and agricultural canals for aquatic habitat. Roads separating the species? terrestrial and aquatic habitat could affect its populations.
?Overall, this is meant to be a first step in identifying reptile and amphibian species that may be at highest risk from roads within their habitat. We hope this assessment will help transportation planning agencies and species managers by highlighting species that may need special attention. This can include considering further research and implementing terrestrial and aquatic mitigation solutions to reduce mortality and to maintain or enhance population connectivity,? says Cheryl Brehme, lead author and biologist with the USGS Western Ecological Research Center.
This research was funded by the USGS and Caltrans. For more information, read the paper online and explore the project webpage on WERC?s website. Amphibian research in this study falls within the national, USGS-led Amphibian Research and Monitoring Initiative (ARMI).
News & Stories ARMI scientist involved in workshop in Hyderabad, India: Long term Wildlife Monitoring, Ecological and Statistical Considerations.
The workshop focused on analytical methods, applications to particular datasets, field techniques, and examples of long-term monitoring programs (from organizational structure and methodology to data and products). The workshop material was rounded out with a variety of speakers including Dr. Arjun Gopalaswamy, Wildlife Conservation Research Unit, Oxford University, Dr. Kim McConkey, University of Nottingham-Malaysia, and Dr. Jagdish Krishnaswamy, Ashoka Trust for Research in Ecology and the Environment.
In addition to lecturing, Erin also spent time mentoring new graduate students and is, (along with Dr. David Miller, former ARMI post-doc, now at The Pennsylvania State University), a member of Gayathri Sreedharan's PhD committee (Jawaharlal Nehru Univesity, New Delhi / CCMB-LaCones). Ms Sreedharan's dissertation title is: Dynamics of enzootic/epizootic Batrachochytrium dendrobatidis infection in a community of stream amphibians from the Western Ghats.
This was a fantastic opportunity to help to build capacity in a country with stunning wildlife, but few resources for conservation. This effort illustrates ARMI's ability to address amphibian conservation needs, but also showcases the impact of USGS programs and leadership in the global community. Building partnerships and sharing information abroad deepens our understanding of the issues and increases our ability to effectively address partner science needs at home.
This loss is worrying. Amphibians are the environment's canaries in the coal mine. Their declines provide early warning signs to scientists that stressors like habitat loss, climate change, pollution and disease are making ecosystems unhealthy. Without amphibians, insect and algae populations multiply, causing cascading effects on other organisms ? including humans...
Read full article here: theconversation.com/saving-amphibians-from-a-deadly-fungus-means-acting-without-knowing-all-the-answers-81739
Associated ARMI publication: armi.usgs.gov/search/results.php
News & Stories Interpretive sign highlighting the federally threatened Chiricahua Leopard Frog debuts at Buenos Aires National Wildlife Refuge
This interpretive sign, the first highlighting an amphibian on BANWR, was originally designed to educate visitors about the Chiricahua Leopard Frog, but the sign has become a template and an inspiration for further educational efforts. Additional signs are in the works at BANWR to provide interpretive information along a planned nature walk near Refuge headquarters and at the flight pen for the federally endangered Masked Bobwhite Quail. Based on the design of the Chiricahua Leopard Frog sign, interpretive information is being created to highlight all of the diverse flora and fauna at BANWR and give the visitor a better idea of the complex and interconnected lives of the organisms they might encounter as they enjoy the scenery and arid landscape of the Refuge.
The Chiricahua Leopard Frog interpretive sign was a concept initiated during a stakeholder meeting in February 2017, at BANWR, where decision science methods were applied to discuss refuge priorities (e.g., Chiricahua Leopard Frog conservation, general refuge management). Stakeholders included personnel from U.S. Fish and Wildlife Service, Arizona Game and Fish Department, U.S. Geological Survey, and the University of Georgia. The sign was designed through collaborative effort among those entities and funded via Jones-Lovich grant in Southwestern Herpetology from
the Herpetologists' League. Work on declining amphibians at BANWR and the Borderlands was initiated by Cecil Schwalbe (USGS, ARMI-retired) and has been continued by Brent Sigafus, Blake Hossack and Erin Muths (Rocky Mountain and Southwest ARMI).
News & Stories New graduate student starts at Colorado State University, funded jointly by ARMI, Colorado State University, and Rocky Mountain National Park.
News & Stories The 2016 ARMI meeting was held at the National Wildlife Health Center (NWHC) in Madison, Wisconsin
News & Stories ARMI conducts national survey for salamander chytrid fungus
Between 2010 and 2014, 99% of the 750,000 salamanders imported into the U.S. were of Asian origin. Due to these obvious threats the U.S. Fish and Wildlife Service has halted importation of many salamanders, including the Asian species popular in the pet trade. However, we need to know if Bsal is already present. The introduction of Bsal into North American wild salamander populations could be particularly problematic given that North America is a global hotspot of salamander diversity being home to nearly half of all salamander species worldwide.
A current map of U.S. sites that have been surveyed to detect Bsal by the ARMI program is available on the ARMI website ( armi.usgs.gov/Bsal-studies/ ).
Those increases, occurring over a large landscape and across hundreds of populations, Knapp said, provide a rare example of amphibian recovery at an ecologically relevant scale. The findings appear in the early online edition of the Proceedings of the National Academy of Sciences.
“We now have a parkwide picture of what’s happening in Yosemite, and it shows convincingly that these frog populations are increasing dramatically, ” said Knapp. “These new results show that, given sufficient time and the availability of intact habitat, the frogs can recover despite the human-caused challenges they face.”
In this comprehensive new study, Knapp teamed with researchers Gary Fellers and Patrick Kleeman (U.S. Geological Survey), David Miller (Penn State University), Vance Vredenburg (San Francisco State University), Erica Rosenblum (UC Berkeley) and Cheryl Briggs (UCSB). Their study analyzed more than 7,000 frog surveys conducted by the USGS and UCSB researchers at hundreds of sites over more than 20 years.
“With this unprecedented, robust data set, we could look for patterns in frog population trends, and potential factors that might be influencing frogs in Yosemite,” Fellers said. “Fortunately, and unexpectedly, we found that in spite of a host of potential factors that could be working to depress or eliminate frog populations, the overall pattern has been for a slow, but widespread recovery of Sierra Nevada yellow-legged frogs.”
Chief among the culprits in Rana sierrae’s once-stark decline is deadly fungal disease called chytridiomycosis, which affects amphibians worldwide and has caused at least 200 species of frogs and salamanders to become extinct within the last 30 years.
To understand how frogs could have recovered in Yosemite despite ongoing chytridiomycosis, in addition to the extensive field surveys, the study also included a laboratory experiment that demonstrated that frogs in Yosemite that have been exposed to the disease for decades are less susceptible than are frogs from populations that are naïve to the disease.
Also a big factor in the original decline: fish introduced years ago into Yosemite waters in the name of recreational angling. According to Knapp, the new research provides clear evidence that efforts in Yosemite to reduce impacts caused by nonnative fish, such as the cessation of fish stocking 25 years ago to restore some lakes to their natural fishless condition, are succeeding.
Describing the group’s findings as “profoundly encouraging,” Kleeman said, “The fact that this is occurring at a landscape scale in the face of multiple stressors lends hope that recovery of the species may indeed be possible.” Still, he cautioned, “Significant population declines are still occurring in other parts of this species’ range, and more work remains to be done to ensure the survival of this emblematic frog of the Sierra Nevada.”
Added Knapp: “The observed recovery of frogs is particularly important because it is based on all of the yellow-legged frog populations in Yosemite. That provides a really strong foundation for the implementation of effective recovery measures.”
News & Stories ARMI scientists Blake Hossack (NOROCK), Brent Sigafus (SBSC) and Erin Muths (FORT), and ARMI post doc Thierry Chambert traveled to Sonora, Mexico, to survey for Sonoran Tiger Salamanders in May 2016
News & Stories New Research Confirms Continued, Unabated and Large-Scale Amphibian Declines: Local Action Key to Reversing Losses
“Implementing conservation plans at a local level will be key in stopping amphibian population losses, since global efforts to reduce or lessen threats have been elusive,” said Evan Grant, a USGS research wildlife biologist who led the study published in Scientific Reports today. “This research changes the way we need to think about amphibian conservation by showing that local action needs to be part of the global response to amphibian declines, despite remaining questions in what is causing local extinctions.”
Amphibian declines are a global phenomenon that this new research demonstrates has continued unabated in the United States since at least the 1960's, and which are occurring even in protected national parks and refuges. Scientists have broadly linked declines to environmental factors like climate, human influence such as land-use change, and contaminants and disease, but have not been able to use actual scientific data on a large scale to discern causes of the ongoing disappearance of amphibian populations.
The new study is the first to test this linkage at a continental scale, and finds that the presence and intensity of the four main threats – human influence, disease, pesticide application, and climate change varies substantially across the US. The causes of the declines are more variable – and more locally driven – across the United States than had been assumed.
For example, the research provides evidence that the average decline in overall amphibian populations is 3.79 percent per year, which supports previous USGS-led research findings from 2013 that showed a similar rate of loss, though the new research finds that the decline rate is more severe in some regions, such as the West Coast and the Rocky Mountains. If this rate remains unchanged, these species would disappear from half of the habitats they occupy in about 20 years.
"Losing 3 or 4 percent of amphibian populations might not sound like a big deal but small losses year in and year out quickly lead to dramatic and consequential declines,” said USGS ecologist Michael Adams, a study coauthor and the lead for the USGS Amphibian Research and Monitoring Initiative, which studies amphibian trends and causes of declines.
David Miller, a professor at Penn State University and the lead biometrician in the study, summarized the extent of the effort.
"This study involved a truly comprehensive and collaborative effort to bring together data from researchers across the United States,” Miller said. “We combined nearly half a million actual observations of 84 species across 61 study areas to answer questions about the causes of wide-scale amphibian declines.”
The research, “Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines,” was led by Evan Grant, USGS; David Miller, Penn State University; Erin Muths, USGS; and 22 others. The study was published in the open-access journal Scientific Reports. Read the full text version here: www.nature.com/articles/srep25625
News & Stories Amphibians in the news
The follow up article was posted online. You can view it here: www.scpr.org/news/2016/05/23/60926/california-s-amphibians-threatened-by-climate-chan/
Elsewhere, Evan Grant communicated with VOA News, Field and Stream magazine, and UPI.com in hope of reaching out to the public on the current state of Amphibians.
Their stories can be viewed here: www.voanews.com/content/mht-unabated-amphibian-decline-found-to-have-myriad-causes/3342617.html
And here: www.upi.com/Science_News/2016/05/23/Amphibians-in-continued-global-decline/8341464025350/
Update: One more article to add to the flurry of recent amphibian updates: www.natureworldnews.com/articles/22906/20160525/are-amphibians-about-to-go-extinct-the-amphibian-crisis-is-worse-than-you-think.htm
At a minimum, most U.S. amphibian species require wetlands to reproduce (6). However, as has happened in other countries, agricultural production, urban expansion, and other land uses have caused the loss or degradation of many U.S. wetlands (5, 10). Furthermore, persistent droughts in western states have caused extensive wetland desiccation recently (11) and increasingly non-stationary climate dynamics threaten to alter past patterns of wetland surface-water availability at even broader spatiotemporal scales, as well as to exacerbate effects from other global change factors (2, 12). More insidiously perhaps, the presence of pathogens that induce lethal amphibian diseases (13), or invasive species that harm native amphibians (14), essentially have caused the loss or degradation of some U.S. wetlands as viable amphibian habitat and could become more pervasive due to climate-induced changes in environmental conditions (12). Thus, assorted drivers of global change have impacted many U.S. wetlands deleteriously, with potentially widespread past, current, and future repercussions for the long-term persistence and conservation of amphibian populations (8, 9).
For these reasons, ARMI scientists and their collaborators have been assessing relations between factors associated with global change, wetland conditions, and the statuses of amphibian populations in each ARMI region across the United States. This research has been conducted most often, but not exclusively, on public lands managed by the Department of Interior and addressed questions regarding the impacts of agricultural land use, contamination due to non-agricultural chemical compounds, oil and gas production, emergent diseases, invasive species, fire, ultraviolet-B radiation (UV-B), and climate ( armi.usgs.gov/table1.php ). Results from these studies have shown the large extent to which the conversion of native land cover to agricultural crops resulted in wetland losses in Iowa, that wetlands in various regions often contain agricultural and non-agricultural contaminants and amphibian pathogens at levels sufficient to be injurious to amphibians or cause population declines, and that historically non-native species have invaded wetlands in some regions and effectively reduced habitat quality for populations of native amphibian species. ARMI researchers also described how effects of western wildfires on wetlands were highly variable and dependent upon wetland characteristics and burn severity whereas levels of dissolved organic carbon in most study wetlands were sufficient to attenuate UV-B rapidly and reduce threats to amphibians in the water. In addition, ARMI scientists studying the impacts of variable climate dynamics on wetland surface-water availability have characterized key relations that underlay the vulnerability of many wetlands and, in turn, amphibian populations to climate change.
Wetlands are fundamentally important natural resources that are vulnerable to the forces of global change (4, 5). As part of assessing the statuses of U.S. amphibian populations and causes of declines (15), ARMI scientists have measured how various drivers of global change have altered the quantity and quality of wetlands in different parts of the country. Results from such research provide resource managers and other stakeholders a unique set of information relevant for conserving wetlands and amphibians both regionally and nationally. They also help to address a larger national need for scientific information on the availability of surface waters for sustaining key ecological processes and providing vital ecosystem services in the face of global change. For more information on ARMI wetlands research in specific areas of the country, please contact the individuals listed in Table 1 ( armi.usgs.gov/table1.php ) or peruse relevant ARMI publications ( armi.usgs.gov/search/index.php ).
1. Gibbons JW. 2003. Terrestrial habitat: a vital component for herpetofauna of isolated wetlands. Wetlands 23(3):630-635.
2. Millennium Ecosystem Assessment. 2005. Ecosystems and Human Well-being: Wetlands and Water Synthesis. World Resources Institute. Washington, D.C. 68 pages.
3. Zedler JB. 2003. Wetlands at your service: reducing impacts of agriculture at the watershed scale. Frontiers in Ecology and the Environment 1(2):65-72.
4. Dudgeon D, Arthington AH, Gessner MO, Kawabata ZI, Knowler DJ, et al. 2006. Freshwater biodiversity: importance, threats, status and conservation challenges. Biological Review 81:163-182.
5. Zedler JB, Kercher S. 2005. Wetland resources: status, trends, ecosystem services, and restorability. Annual Review of Environmental Resources 30:39-74.
6. Lannoo ML, Gallant AL, Nanjappa P, Blackburn L, Hendricks R. 2005. Introduction. In: Amphibian Declines: The Conservation Status of United States Species. ML Lannoo (ed). University of California Press. Berkeley and Los Angeles, California. 1094 pages.
7. Gibbons JW, Winne CT, Scott DE, Willson JD, Glaudas X, et al. 2006. Remarkable amphibian biomass and abundance in an isolated wetland: implications for wetland conservation. Conservation Biology 20(5):1457-1465.
8. Hof C, Araujo, MB, Jetz W, Rahbek C. 2011. Additive threats from pathogens, climate, and land-use change for global amphibian diversity. Nature 480:515-519.
9. Wake DB. 2012. Facing extinction in real time. Science 335:1052-1053.
10. Gallant AL, Sadinski W, Roth MF, Rewa CA. 2011. Changes in historical Iowa land cover as context for assessing the environmental benefits of current and future conservation efforts on agricultural lands. Journal of Soil and Water Conservation 66(3):67A-77A.
11. McMenamin SK, Hadly EA, Wright CK. 2008. Climatic change and wetland desiccation cause amphibian decline in Yellowstone National Park. Proceedings of the National Academy of Sciences of the United States of America 105(44):16988-16993.
12. Rahel FJ, Olden JD. 2008. Assessing the effects of climate change on aquatic invasive species. Conservation Biology 22(3):521-533.
13. Muths E, Corn PS, Pessier AP, Green DE. 2003. Evidence for disease-related amphibian decline in Colorado. Biological Conservation 110:357-365.
14. D’Amore A, Kirby E, McNicholas M. 2009. Invasive species shifts ontogenetic resource partitioning and microhabitat use of a threatened native amphibian. Aquatic Conservation: Marine and Freshwater Ecosystems 19(5):534-541.
15. Adams MJ, Miller DAW, Muths E, Corn PS, Grant EHC, et al. 2013. Trends in amphibian occupancy in the United States. PLoS ONE 8(5): e64347.doi:10.1371/journal.pone.0064347.
The Department of the Interior is working proactively to protect the nation’s amphibians. The USGS report highlights cooperative research and management efforts needed to develop and implement effective pre-invasion and post-invasion disease-management strategies if Batrachochytrium salamandrivorans (Bsal) enters and affects salamanders within the United States. In January, the United States Fish and Wildlife Service published a rule listing 201 salamander species as injurious under the Lacey Act, which will reduce the likelihood of introduction of Bsal into the country.
Although Bsal has not yet been found in wild U.S. salamander populations, scientists caution it is likely to emerge here because of the popularity of captive salamanders as household pets, in classrooms and in zoos; the captive amphibian trade is a known source of salamanders afflicted with the fungus.
Amphibians are the most endangered groups of vertebrates worldwide, with another fungus closely related to Bsal(Bd) contributing to amphibian die-offs and extinctions globally over the last two decades.
“Based on the kinds of species affected and the fact that the United States has the highest salamander diversity in the world, this new pathogen is a major threat with the potential to exacerbate already severe amphibian declines,” said Evan Grant, ARMI biologist and lead author of the USGS report. “We have the unusual opportunity to develop and apply preventative management actions in advance.”
Bsal was first identified in 2013 as the cause of mass wild salamander die-offs in the Netherlands and Belgium. Captive salamander die-offs due to Bsal have occurred in the United Kingdom and Germany. Scientists believe Bsal originated in Asia and spread to wild European populations through the import and export of salamanders.
The USGS brought together scientists and managers from federal and state agencies that oversee resource conservation and management to identify research needs and management responses before Bsal arrives and becomes entrenched in the country. USGS, the USFWS, U.S. Forest Service, U.S. Department of Defense, National Park Service, zoos, and U.S. and international universities participated in the Bsal workshop.
Key findings in the report include:
1) Bsal is highly likely to emerge in U.S. populations of wild salamanders through imports of potentially infected salamanders.
2) Management actions targeted at Bsal containment after arrival in the United States may be relatively ineffective in reducing its spread.
3) A coordinated response, including rapid information sharing, is necessary to plan and respond to this potential crisis.
4) Early detection of Bsal at key amphibian import locations, in high-risk wild populations, and in field-collected samples is necessary to quickly and effectively implement management responses.
The workshop and Open-File Report were supported by USGS ARMI and the USGS Powell Center for Analysis and Synthesis.
To read the report, go to: dx.doi.org/10.3133/ofr20151233
News & Stories ARMI gave IGNITE talks in Washington D.C.
News & Stories Salamander chytrid fungus working group; June 2015
Over 28 million amphibians were imported in the US over a 6 year period during the last decade and that importation rate has not declined. Thus, there is serious concern that the disease may be introduced into the US in the near future, if it is not already present. This is particularly alarming because the eastern US is home to the highest diversity of salamanders in the world, including 141 species in the known susceptible family, Plethodontidae. Bsal is also known to be lethal to other US genera in the family Salamandridae (the rough skinned newt, Taricha granulosa, in the Pacific Northwest, and the Eastern newt Notophthalmus viridescens). This pathogen has the potential to have devastating consequences for native US salamanders, similar to extirpations observed in frog species in South America and Australia.
Therefore, a primary objective is to design a sampling strategy to detect the occurrence of the disease in the US (i.e., surveillance). Regardless of whether the disease already occurs in the US, a monitoring design must be developed to identify, with sufficient power, the probability the disease occurs in amphibian populations throughout the US, which must be assessed annually along with population estimates to understand the spread of Bsal and the fate of infected populations. A monitoring program in absence of a management plan is of limited use, and the design of a surveillance and monitoring program must consider possible management responses to monitoring results.
The threat of Bsal to US species provides a unique opportunity to address the introduction, spread, population effects, and control strategies for a novel infectious disease before we are dealing with widespread declines in native populations. By framing this crisis as an opportunity for learning and approaching the problem in a formal decision making context, we will increase the probabilities of early detection, containment, and successful mitigation of the Bsal pathogen. This working group will also provide a template for planning actions for future novel infectious diseases.
There is no coordinated effort to bring together scientists, managers, and policy makers to confront this crisis. In fact, such an approach to emerging infectious diseases is unprecedented, though this conceptual approach has been suggested in other disease outbreak contexts. We propose to bring together scientists, managers, and policy makers to develop an optimal surveillance and monitoring plan based on an adaptive management framework. The plan will also prescribe potential actions based on theoretical but likely scenarios develop from our experience with the amphibian chytrid fungus (Bd) in the US and other countries and the recent experience of our colleagues in Europe with Bsal. We will use a formal, structured working group with participation from scientists and managers from the US and Europe to frame an adaptive management and monitoring plan for this disease.
A formal working group, led by Amphibian Research and Monitoring Initiative (ARMI) scientists at the Patuxent Wildlife Research Center (Evan Grant), Fort Collins Science Center (Erin Muths) and Forest and Rangeland Ecosystem Science Center (Mike Adams) is scheduled to be held at the Powell Center for Analysis and Synthesis in Fort Collins, CO in June.
News & Stories 2015 ARMI annual meeting
News & Stories ARMI research on amphibian chytrid fungus occupancy and detection in wetlands featured in the Environmental Monitor
For more coverage from Environmental Monitor, follow the jump: www.fondriest.com/news/new-amphibian-chytrid-fungus-tests-ease-search-wide-ranging-frog-disease.htm
News & Stories ARMI recognized!
News & Stories ARMI recognized!
News & Stories Endangered Mountain Yellow-legged Frogs Released into Wild
While loss of habitat is the main reason behind amphibian decline, in the Des Moines Lobe, amphibians are further challenged by an environment potentially compromised by contaminants and their limited mobility exacerbates the effects of habitat fragmentation.
In response to observed ecosystem degradation in environmentally sensitive areas the USDA introduced the Conservation Reserve Enhancement Program (CREP) to target high-priority conservation issues. In the year 2001, the state of Iowa partnered with USDA and developed a CREP to strategically locate and restore wetlands on private land that receive run-off from multiple sub-surface tile drains to help reduce the export of nitrates from agricultural watersheds before the water reaches the Mississippi River and the Gulf of Mexico. Although CREP wetlands are intended primarily to reduce nitrogen to protect drinking water and reduce hypoxia in the Gulf of Mexico, they provide other ecosystem services such as providing wildlife habitat and recreational opportunities. For example, CREP wetlands and their adjoining grass buffers provide forage and cover for waterfowl and upland game.
For complete article, see here: www.fort.usgs.gov/science-feature/890
News & Stories A surprising find during amphibian research
ARMI uses automated recording units to monitor calling frogs and toads in the Picayune Strand State Forest of Southwest Florida. This state forest, once a failed residential development project known as the Southern Golden Gates Estates, is undergoing hydrological restoration as part of the Comprehensive Everglades Restoration Plan. Scientists from the Southeast and Southcentral ARMI Regions are testing the idea that amphibians are reliable indicators of restoration success. The sound you hear was confirmed by experts from Big Cypress National Preserve to be the yowling call of a female Florida Panther, possibly signalling to potential mates.
News & Stories 2013 ARMI Meeting
News & Stories ARMI project selected by The Powell Center - Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models
The proposal moves forward from the recently published paper describing the magnitude of amphibian declines in the U.S. (Adams et al. 2013), and will now examine the mechanisms of decline using a data driven, but model-based, approach. Though focused on North America, the insights will be applicable to other systems and will lay the foundation for a larger, perhaps international, assessment of mechanisms behind global amphibian declines.
The 15 member working group includes not only ARMI scientists and data collected over the last 10 years, but others with long-term data on amphibians including scientists from Canada, Mexico and Europe. The first working group meeting will be held in Fort Collins in January 2014. A hallmark of the Powell Center is that it is "a scientist-driven institution where leveraging existing research efforts produces powerful new insights and moves scientific understanding and its inclusion into management forward at an accelerated pace."
Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines across species and landscapes suggests that causal factors at a broader scale are also important. Elucidation of the mechanisms driving population change has lagged, mainly because data have been unavailable at continental scales.
We propose to address this need by assembling data to answer questions about broad-scale drivers of amphibian decline. We will examine alterations in timing and availability of surface-water habitat (driven principally by climate change), as first order variables that control the probabilities of breeding, successful metamorphosis, and return rates of amphibians. Climate change (and its influence on shifting temperatures) is also correlated with other agents of decline such as disease and amplification of cyclical population dynamics; we consider these second-order effects.
Furthermore, data on other causal mechanisms are not available at broad-scales. We will use monitoring data (core data from USGS Amphibian Research and Monitoring Initiative, supplemented by data from collaborators in Canada, the U.S., and Mexico) and state-of-the-art statistical techniques to examine broad-scale mechanisms associated with changes in amphibian occupancy.
We will develop hypotheses for climate-induced shifts in occupancy dynamics, and test these hypotheses using a dataset representing many individual projects and regions from across North America. We will formulate the problem in hierarchical Bayesian models to examine multi-scale processes affecting patterns of species occupancy. This analysis of population trends across multiple spatial scales will facilitate the first rigorous quantitative examination of mechanisms affecting occupancy of amphibians across North America, and provide a continent-wide assessment of the contribution of climate-related factors to declines in amphibian populations. Hypotheses and methods developed through this collaborative effort will be useful in other locations experiencing amphibian declines (e.g., Australia, Europe) and our modeling approach will be useful for assessments of other taxa.
Associated PDF: dx.plos.org/10.1371/journal.pone.0064347
News & Stories ARMI researchers interviewed on live radio show
Tune in to hear the show! news.wgcu.org/post/amphibians-decline
News & Stories Pesticide Accumulation in Chorus Frogs of the Sierra Nevada
News & Stories The Oregonian meets ARMI scientist Michael Adams
Adams, lead author of the recent paper on national declines in amphibian populations ( dx.plos.org/10.1371/journal.pone.0064347 ) discussed the findings of the paper and what it takes to acquire and analyze these kinds of data.
LINK to The Oregonian www.oregonlive.com/environment/index.ssf/2013/06/as_numbers_decline_hunting_for.html
News & Stories Endangered Frogs Get Helping Hands on Road to Recovery
Watched over by a team of Federal, State, and private scientists, the mountain yellow-legged frog continues to maintain a perilous toehold in the mountains of southern California. Mountain yellow-legged frogs in southern California live in perennial streams in portions of the San Gabriel, San Bernardino, and San Jacinto Mountains. The upper elevation stream segments inhabited by the frogs are generally 1,214 to 7,546 feet above sea level.
The U.S. Fish and Wildlife Service listed the mountain yellow-legged frog in southern California as endangered in 2002. Reduced to fewer than 200 individuals by 2003, efforts to boost the species’ population have included captive breeding, reintroducing captive offspring to historic habitat, and conducting scientific research into the causes of the species’ decline.
The froglets set free at the James San Jacinto Mountains Reserve today were raised by the San Diego Zoo Institute for Conservation Research. In addition, a female adult frog raised by the Los Angeles Zoo and outfitted with a transmitter will also be released at the site.
“It is truly a thrill to see the mountain yellow-legged frog once again in Indian Creek where until very recently, the mid-1990s, natural populations existed,” said Jennifer Gee, director of James San Jacinto Mountains Reserve.
“We are optimistic that the release of froglets will be successful and help re-establish a population within Hall Canyon,” said Mike Giusti, California Department of Fish and Wildlife senior environmental scientist. “The success of this effort will be used as a model for re-establishment of frogs in other streams within the frog’s historic range.”
Factors that impact this species include chytrid fungus, a serious threat to the frogs in the U.S. and around the world; large wildfires that may bury the species’ stream habitats in ash and debris; and recreational activities that may impact frog recovery by damaging egg sacs when people swim in or cross occupied streams.
“The mountain yellow legged frog lives completely within the Angeles and San Bernardino National Forests. The Forest Service identified the need to remove tadpoles from the forest during drought conditions, which subsequently jump-started the current captive breeding population,” said Anne Poopatanapong, district biologist for San Bernardino National Forest. “We continue to administer funds to conduct recovery actions, and the Forest Service is implementing management actions, including trout removal on the North Fork San Jacinto River and Fuller Mill Creek and hazardous fuels reduction on the North Fork, to help increase suitability of habitat for this fragile amphibian.”
“We often think of endangered species as something exotic in far-away countries,” says Adam Backlin, an ecologist with the U.S. Geological Survey Western Ecological Research Center who leads the field monitoring effort on the species. “But we’ve got this one right here in southern California, and what we learn from this reintroduction and monitoring effort will teach us a lot about how to help other declining amphibian species in the U.S. and around the world.”
The frog is one of three frog or toad species native to southern California that is protected under the Endangered Species Act – the other two species are the endangered arroyo toad and the threatened California red-legged frog.
Both the San Diego Zoo Institute for Conservation Research and the Los Angeles Zoo and Botanical Gardens are actively rearing the mountain yellow-legged frog in captivity for release to the wild. Funding for the captivity and reintroduction program has been provided by the California Department of Transportation, as mitigation for the State Route 330 emergency project. Since 2011, the San Diego Zoo Institute for Conservation Research has reared about 300 frogs and the Los Angeles Zoo and Botanical Gardens has produced 210.
“We have cared for hundreds of mountain yellow-legged frogs and watched as they metamorphosed from tiny tadpoles into juvenile frogs, and we are excited to release them into the wild,” said Frank Santana, research coordinator for San Diego Zoo’s Institute for Conservation Research. “With a dedicated post-release monitoring plan we expect to learn a great deal of information from this reintroduction as we work towards restoring this native species to southern California mountain streams.”
"The Los Angeles Zoo and Botanical Gardens is proud to participate in this program," states curator of reptiles & amphibians, Ian Recchio. “In 2011, the Los Angeles Zoo and Botanical Gardens’ reptile and amphibian staff released 160 mountain yellow-legged frog tadpoles into the San Jacinto Mountains, with the hope of significantly increasing the wild population of this species.”
In May of this year, this partnership effort to recover the mountain yellow-legged frog was recognized by the California Transportation Foundation as the Sustainable Environmental Enhancement Program/Project of the Year. The Announcement and video are available at: www.transportationfoundation.org/transportation-awards/
Efforts such as this are important to ensuring the conservation of our native amphibians which are in trouble. A nine-year effort to survey amphibians across the United States found that all species are declining, even those within wildlife refuges, national parks, and other protected areas. Researchers have not been able to identify all the potential factors causing the declines, which may include habitat loss, effects of pesticides, invasive species, and disease. A full copy of the report is available online at www.usgs.gov/newsroom
Photos and video of the release can be downloaded at from the San Diego Zoo Global website at sandiegozoo.box.com/s/nffi2p8g2wuynooh63zx
Additional photos of the frogs are available online at the USGS Photo Gallery gallery.usgs.gov/photos/05_19_2011_mQHt38Vjj1_05_19_2011_6
Short video of release: www.mydesert.com/article/20130612/NEWS07/306120029/Endangered-frogs-reintroduced-into-wilderness
Citation: Adams M.J., Miller D.A.W., Muths E., Corn P.S., Grant E.H.C., Bailey L.L., Fellers G.M., Fisher R.N., Sadinski W.J., Waddle H. & Walls S.C. (2013). Trends in amphibian occupancy in the United States. PLoS ONE. dx.plos.org/10.1371/journal.pone.0064347
Download answers to Frequently Asked Questions on this study (PDF): armi.usgs.gov/docs/Adams%20et%20al%202013%20PLoS%20Amphibian%20Decline%20USGS%20ARMI%20FAQ.pdf
Read the press release from USGS: www.usgs.gov/newsroom/article.asp
Walls and her colleagues synthesized what is known about current and possible future effects of extreme precipitation events on amphibians across the country; and then report findings from these actual weather events on mole salamanders (Ambystoma talpoideum) in St Marks National Wildlife Refuge, in Florida’s panhandle.
Further West, Waddle and his team reported the effect of restoring the hydrological flows to former agricultural lands in the Lower Mississippi Valley on species diversity and abundance of native frogs and toads. This voluntary restoration program is made possible through the U.S. Department of Agriculture’s Wetlands Reserve Program.
Waddle,J. H., B. M. Glorioso, and S. P. Faulkner. 2013. A Quantitative Assessment of the Conservation Benefits of the Wetlands Reserve Program to Amphibians. Restoration Ecology Vol. 21, pp. 200–206.
Walls, S. C., W. J. Barichivich, and M. E. Brown. 2013. Drought, Deluge and Declines: The Impact of Precipitation Extremes on Amphibians in a Changing Climate. Biology Vol. 2, pp. 399-418.
Walls, S. C., W. J. Barichivich, M. E. Brown, D. E. Scott, and Blake R. Hossack. 2013. Influence of Drought on Salamander Occupancy of Isolated Wetlands on the Southeastern Coastal Plain of the United States. Wetlands Vol.33, pp 345-354.
News & Stories e-DNA Technology. Keeping pace with your questions!
A new USGS Fact Sheet presents the basics of using eDNA as a tool and the questions you should be asking: pubs.usgs.gov/fs/2012/3146/
News & Stories Blackrock: Biological Hotspot and Hotbed of Collaboration
Amphibian decline is a problem of global importance, with over 40 percent of species considered at risk. This phenomenon is not limited to the tropics or to other countries; amphibian species in the United States are also declining, contributing to the larger global phenomenon. For example, in Wyoming, the Wyoming toad has been extirpated in the wild and the boreal toad is a species of special concern. Habitat loss (especially of wetlands) and disease are two examples of perturbations contributing to amphibian decline.
Wetlands harbor a variety of wildlife from large ungulates to amphibians the size of a U.S. quarter. Because many amphibians depend on wetlands for breeding, feeding, and rearing young, the availability of wetlands is important to maintaining amphibian diversity and presence across suitable habitat.
Amphibian Research in Wyoming
In northwestern Wyoming, scientist Erin Muths (U.S. Geological Survey, Fort Collins Science Center) has been leading a team of researchers investigating amphibian decline at a study site on the Blackrock Ranger Station compound on the Bridger-Teton National Forest. The work began in 2003, when Dr. Muths and David Pilliod (USGS Forest and Range Ecosystem Science Center) were awarded competitive funding from the USGS Amphibian Research and Monitoring Initiative (ARMI). The research team of Dr. Muths, Dr. Pilliod, and Drs. Steve Corn and Blake Hossack (USGS Northern Rocky Mountain Science Center) collaborates with the U.S. Forest Service (USFS) and other entities to study population demographics and disease ecology for the four species of amphibians that reside on the USFS Blackrock compound.
The Blackrock research site focused initially on an oxbow pond separated from the Buffalo Fork River by levees, where boreal toads (Anaxyrus boreas), Columbia spotted frogs (Rana luteivensis), chorus frogs (Pseudacris maculata), and tiger salamanders (Ambystoma tigrinum) were breeding. However, natural and human-made changes to the immediate landscape have caused concomitant changes to breeding habitat and increased the scope of the research.
Construction on Wyoming Highway 26/U.S. Highway 287, which disturbed existing wetlands, included establishing a mitigation site (as required by federal and state laws). The mitigation site, located on the USFS Blackrock compound near the existing research site, may prove more valuable to amphibians than first thought. Heavy, late-spring runoff in 2011 and 2012 breached the levees between the oxbow and the river. These natural events are thought to have wiped out amphibian breeding efforts at the oxbow, leaving reproduction at the mitigation site as the only viable effort in these years. As a result, after only two years since establishment, two of the four species of amphibians that bred in the oxbow are using the mitigation site to breed.
In the Rocky Mountains, the timing of amphibian reproduction is linked to the timing of snowmelt and subsequent spring runoff. These springtime events are likely to be affected by climate change, which in turn can influence wetland availability and persistence. Wetlands (both natural and constructed, like those established through mitigation efforts) are vital to the reproduction and persistence of amphibians across the landscape. Understanding climate dynamics in relation to wetland availability is an important component of managing landscapes that provide habitat for a wide diversity of wildlife, from large ungulates to toads to macroinvertebrates.
Collaboration Is Key:
Collaborative research among USGS scientists, the Northern Rockies Conservation Cooperative, and the USFS has been funded for 3 years by the Wyoming Highway Department (WYDOT). This research effort will assess mitigation sites and natural sites to compare differences in habitat (physical site characteristics), demographics of the amphibian species, insect communities, disease presence and impact, and amphibian occupancy across the immediate landscape. Our goals are to track multiple populations of amphibians over time to better understand population-level host-pathogen dynamics, assess potential shifts in occupancy across the landscape, and determine the efficacy of the mitigation efforts at Blackrock. Results of the investigation will support Forest Service management of the amphibians and help refine protocols for future mitigation efforts required of WYDOT.
USGS research over the last 10 years has contributed to our understanding of site characteristics and the population dynamics of the boreal toad, providing information that is critical to the expanded project detailed above. For example, our previous data indicate that the boreal toad population at Blackrock is declining at 5–6 percent per year, and that disease due to the amphibian chytrid fungus (Batrachochytrium dendrobatidis) is contributing to this decline (Muths et al. 2008, Pilliod et al. 2010, Murphy et al. 2009, 2011). This fungal disease is not unique to Wyoming but is affecting amphibian populations worldwide. However, we’ve also shown that the Blackrock toad population is not crashing as has been the fate of some other boreal toad populations in the western United States (e.g., Muths et al. 2003). In fact, at some level the population is compensating for poor survival by increasing recruitment (Muths et al. 2011).
In addition, the value of our early data on boreal toads and chorus frogs will be increased by complementary data on salamanders and Columbia spotted frogs. Including other amphibian species will allow us to unravel connections among species and examine disease resistance, the roles of species as vectors, and competition.
In a larger context, understanding how amphibians (1) use previous natural habitat and mitigation sites and (2) shift demographically in response to disease will inform their conservation. As climate change affects amphibian habitat, especially wetlands, detailed information about assemblages of amphibians in their natural habitat becomes even more important. The USGS research team’s work at the Blackrock site is poised to contribute to these efforts.
Corn, P.S., E. Muths, and D.S. Pilliod. 2011. Long-term observations of boreal toads at an ARMI apex site. Pages 101–104 in Andersen, C., ed. Questioning Greater Yellowstone’s future: Climate, land use, and invasive species. Proceedings of the 10th Biennial Scientific Conference on the Greater Yellowstone Ecosystem. October 11–13, 2010, Yellowstone National Park. Yellowstone National Park, WY, and Laramie, WY: Yellowstone Center for Resources and University of Wyoming William D. Ruckelshaus Institute of Environment and Natural Resources.
Murphy, P.J., S. St-Hilaire, S. Bruer, P.S. Corn, and C.R. Peterson. 2009. Distribution and pathogenicity of Batrachochytrium dendrobatidis in boreal toads from the Grand Teton area of western Wyoming. EcoHealth 6: 109–120.
Murphy, P.J., S. St-Hilaire and P.S. Corn. 2011. Temperature hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads. Diseases of Aquatic Organisms 95: 31–42, doi: 10.3354/dao02336.
Muths, E., P.S. Corn, A.P. Pessier and D.E. Green. 2003. Evidence for disease related amphibian decline in Colorado. Biological Conservation110 (2003): 357–365.
Muths, E., D.S. Pilliod, and L. Livo. 2008. Distribution and environmental limitations of an amphibian pathogen in the Rocky Mountains, USA. Biological Conservation 141: 1484–1492.
Muths, E., D.S. Pilliod, and R.D. Scherer. 2011. Compensatory effects of recruitment and survival on population persistence. Journal of Applied Ecology48: 873–879.
Pilliod, D.S., E. Muths, R.D. Scherer, P.E. Bartelt, P.S. Corn, B.R. Hossack, B.A. Lambert, R. McCaffery, and C. Gaughan. 2010. Effects of amphibian chytrid fungus on individual survival probability in wild boreal toads. Conservation Biology24: 1259 –1267
News & Stories Making better predictions: using multispecies models to inform habitat management for amphibians
Zipkin, EF, EH Campbell Grant, WF Fagan. Evaluating the predictive abilities of community occupancy models using AUC while accounting for imperfect detection. Ecological Applications Preprint www.esajournals.org/doi/pdf/10.1890/11-1936.1
News & Stories ARMI will be attending The World Congress of Herpetology
The World Congress focuses on quantifying, understanding and searching for solutions to ameliorate the impacts of what scientists believe is the current expression of the world’s sixth major extinction which has impacted amphibians, and possibly reptiles, disproportionately across the planet.
More on the World Congress of Herpetology
News & Stories Reptiles, Amphibians in US Succumbing to Deadly Ranavirus
Follow this link for full story: www.voanews.com/english/news/usa/Reptiles-Amphibians-in-US-Succumbing-to-Deadly-Ranavirus-147292065.html
News & Stories ARMI Pathologist Dr. David Green interviewed by National Public Radio on emerging disease of amphibians and turtles.
In addition to the site in Maryland, USGS scientists have already isolated ranaviruses from die-offs among more than 20 species of turtles and amphibians in mortality events ranging from one to thousands of individuals in over 25 states.
Die-offs of amphibians from ranavirus have occurred on private, State, and Federal lands, including several National Parks and Wildlife Refuges. Many of the amphibian species involved in die-offs are fairly common and widespread in the United States, but some are either declining in number or are already threatened or endangered.
Follow the link to hear the full report: wamu.org/programs/metro_connection/12/03/09/scientists_scramble_to_understand_a_mystery_virus
For more info on amphibian diseases, visit the USGS National Wildlife Health Center website here: www.nwhc.usgs.gov/
Just as in other countries, the effort in the United States requires collaboration and creative solutions.
In a recent interview conducted by Voice of America, reporter Rebecca Ward interviews several wildlife professionals about their research and management projects to reverse amphibian declines.
Dr. Evan Grant, Regional Coordinator of NE ARMI spoke with Rebecca about an adaptive management research project developed collaboratively by the ARMI program, Dr Larissa Bailey and Adam Green from Colorado State University and the US Fish and Wildlife
Service (Patuxent Research Refuge) on the manipulation of ponds to benefit wood frogs under predicted climate change scenarios. Check out the video link!
News & Stories Did you hear that right?
Two experiments conducted by ARMI researchers in the past 2 years highlight the need to account for false positive errors when interpreting survey results. We used an automated broadcast system to simulate typical conditions for call surveys (Frog Radio). Thirty-six observers who are involved with monitoring frogs and toads participated in the Frog Radio experiments, logging more than 100,000 observations. A major finding was that, when recording observations under typical field conditions that include multiple calling species, background noise, and repeated observations, even the most experienced observers made a significant number of false positive errors. Overall, we found 5-8% of recorded observations were for species that were not actually played.
False positive errors are a significant component of many ecological data sets, not only auditory surveys. Error rates such as those observed during the Frog Radio experiment, can lead to severe biases in conclusions about ecological systems if they are not accounted for. This motivated us to develop new statistical methods to account for false positive errors when estimating trends in species occurrence. We built on existing methods that account for missed detections, to jointly deal with both error types. We demonstrated the new methods using call survey and visual encounter data for frogs and toads in and around the C&O Canal National Historic Park.
Results published in:
McClintock, B.T., L.L. Bailey, K.H. Pollock, and T.R. Simons. 2010. Experimental investigation of observation error in anuran call surveys. Journal of Wildlife Management 74:1882-1893.
Miller, David A., James D. Nichols, Brett T. McClintock, Evan H. Campbell Grant, Larissa L. Bailey, and Linda A. Weir. 2011. Improving occupancy estimation when two types of observational error occur: non-detection and species misidentification. Ecology 92:1422–1428.
News & Stories Annual ARMI meeting held in St. Louis on November 13th 2011
management, hydrological modeling, emerging diseases, pesticides, invasive species, habitat restoration, and population monitoring. ARMI's research portfolio is diverse to correspond with the wide variety of stressors that impact amphibian populations. ARMI provides the essential scientific information to support management actions for the restoration and conservation of the nation's amphibians.
News & Stories Low-Cost DNA Technique Detects Stream Amphibians
Results were published in: Goldberg CS, Pilliod DS, Arkle RS, Waits LP (2011) Molecular Detection of Vertebrates in Stream Water: A Demonstration Using Rocky Mountain Tailed Frogs and Idaho Giant Salamanders. PLoS ONE 6(7): e22746. doi:10.1371/journal.pone.0022746.
The statistical modeling approach is reported in a recent issue of The Journal of Wildlife Management. The paper demonstrates how the flexibility and utility of occupancy models makes them such a valuable tool for asking the different kinds of questions that are relevant to resource managers.
Susan C. Walls, J. Hardin Waddle and Robert M. Dorazio. 2011. Estimating Occupancy Dynamics in an Anuran Assemblage from Louisiana, USA.
The Journal of Wildlife Management, 75(4):751-761. 2011.
News & Stories Dramatic Changes to Amphibian Habitat Across Iowa
A look at historical landscape conditions in Iowa can provide important background for understanding where amphibians and other species can live there today. We performed such a retrospective analysis to help us assess the environmental benefits from conservation programs supported by the U.S. Department of Agriculture. Our results illustrate widespread landscape and habitat changes in Iowa, including a statewide homogenization of formerly more diverse regional patterns of wetlands.
We first turned back the clock by examining digitized maps of archived land-cover information collected during the 1830s-1850s via surveys contracted by the Government Land Office. This information was intended to promote private ownership and settlement. Surveyors were required to measure and map the land cover they encountered along transects that became Iowa’s road system. Quilting the digitized maps provided a glimpse of the past across Iowa (Figure 1A), when the landscape was dominated by grasslands (covering 80% of the surface area) and woodlands (covering 18% of the surface area). Today, grasslands occur only on about 5% of the landscape and woodlands on about 7%, with the former replaced largely by cropland and the latter by pasture and hay fields (Figure 1B).
[CAPTION]Figure 1. Iowa land cover in the mid-1800s (A) and as of 2001 (B, mapped with data from the National Land Cover Database, www.mrlc.gov/nlcd.php). Figure used with permission from the Journal of Soil and Water Conservation, see Gallant et al. (2011).[/CAPTION]
Wetlands in the 1800s were distributed in regional patterns. Moderate to high densities of wetlands occurred in the Des Moines Lobe (the southern extent of the Prairie Potholes Region), Missouri Alluvial Plain, Iowan Surface, and Mississippi Alluvial Plain ecoregions (Figure 2A, C). Wetlands were naturally less abundant elsewhere in Iowa because the hydrogeologic characteristics of the landscape did not favor wetland formation. Wetlands are distributed more evenly across Iowa today (Figure 2B) due, for example, to humans draining prairie-pothole wetlands in the Des Moines Lobe to improve land for crops, and impounding water in other ecoregions to support livestock and recreation and to control flooding. Thus, in addition to altering upland habitat, humans dramatically changed surface-water habitat for amphibians and other species across Iowa.
[CAPTION]Figure 2. Distribution of wetlands mapped with data from the Government Land Office (A) and the U.S. Fish and Wildlife Service’s National Wetlands Inventory (B; www.fws.gov/wetlands ). Ecoregions (C; www.epa.gov/wed/pages/ecoregions/moia_eco.htm ) are: 40a=Loess Flats and Till Plains, 47a=Loess Prairies, 47b=Des Moines Lobe, 47c=Iowan Surface, 47d=Missouri Alluvial Plain, 47e=Steeply Rolling Loess Prairies, 47f=Rolling Loess Prairies, 47m=Western Loess Hills, 52b=Paleozoic Plateau/Coulee Section, 72d=Upper Mississippi Alluvial Plain. Figure modified and used with permission from the Journal of Soil and Water Conservation, see Gallant et al. (2011).[/CAPTION]
Patterns of soil characteristics across Iowa also provided evidence today’s wetlands are distributed differently from those of the past. We compiled a statewide map depicting soils formed under repeated seasonally wet conditions through time (hydric soils) and found wetlands would have been most common in the Des Moines Lobe, Missouri Alluvial Plain, Western Loess Hills, Iowan Surface, and Mississippi Alluvial Plain ecoregions (Figure 3) and less common in other ecoregions.
[CAPTION]Figure 3. Percent of local surface area covered by hydric soils mapped with data from the Soil Survey Geographic Database (soils.usda.gov/survey/geography/ssurgo ). Figure used with permission from the Journal of Soil and Water Conservation, see Gallant et al. (2011).[/CAPTION]
We obtained further evidence on the nature of changes in wetland distributions over time from the National Wetlands Inventory database (www.fws.gov/wetlands ). Distinguishing created wetlands from those more natural in origin (though, even these typically have been altered in various ways) showed the majority of created wetlands occurred in ecoregions that historically did not support many wetlands (Figure 4).
[CAPTION]Figure 4. Wetlands created through impoundments and excavation compared with wetlands of more natural origins, mapped from the U.S. Fish and Wildlife Service’s National Wetlands Inventory database (www.fws.gov/wetlands ). Figure used with permission from the Journal of Soil and Water Conservation, see Gallant et al. (2011).[/CAPTION]
We also learned wetlands in all Iowa ecoregions are smaller today than in the past, and their size ranges now are much more similar across ecoregions.
Our results help illustrate how humans have eliminated or altered much of the native upland and wetland habitat for amphibians in Iowa during the past 150 years. The agricultural practices responsible for many of these changes continue to pose challenges to the persistence of extant amphibian populations in the form of tilling, pesticide and fertilizer applications, livestock use of wetlands, habitat fragmentation, and effects on microclimates, among others. Understanding the array of stressors impinging upon current habitat and populations in Iowa relative to historical land cover and human activity provides us essential context for helping the U.S. Department of Agriculture determine the environmental benefits of their conservation programs in the State. Given the nature and extent of habitat loss, alteration, and fragmentation in Iowa, maximizing such benefits is an important goal.
For additional information:
Gallant, A.L., Sadinski, W., Roth, M.F., and Rewa, C.A., 2011, Changes in historical Iowa land cover as context for assessing the environmental benefits of current and future conservation efforts on agricultural lands: Journal of Soil and Water Conservation, v. 66, no. 3, p.67A-77A. (www.jswconline.org/content/66/3/67A.full.pdf+html ).
News & Stories Advanced Tools for Acoustic Sampling of Calling Amphibians
Ecologists long have imagined how advanced digital sound recorders and analytical software could improve amphibian research and conservation. First and foremost, perhaps, such tools would provide an unprecedented ability to collect more comprehensive data on calling activity and dynamics. These tools also would help reduce or eliminate limitations associated with commonly employed human surveys of calling amphibians. These limitations often include: insufficient numbers of surveyed sites or repeat surveys to accurately reflect the presence of target species or to satisfy statistical requirements; variable, but typically undocumented, errors among surveyors in identifying sounds; non-standardized sampling methods of insufficient rigor to promote comparative surveys across large spatial scales or permit straightforward integration with data collected via satellite and other ground-based sensors; and a complete lack of archived sounds from survey sites. Only recently have cost-effective, sophisticated, digital acoustic recorders necessary to record autonomously, and frequently, during extended field deployments become available commercially. And, very importantly, software required to meaningfully analyze voluminous quantities of digital call data has been developed.
Since 2005, scientists from ARMI’s Midwest Region (ARMI-MR) have worked specifically to facilitate improvements in the development and availability of cost-effective acoustic recorders and new analytical software. We needed these tools to enable us to build partnerships and leverage resources to study amphibian populations in ways and places we could not do alone. These are key ARMI objectives to help meet regional and national goals. The recent availability of improved acoustic recorders and analytical software has proven to be the cornerstone of our region’s success in leading the development and implementation of a growing network of partners and research sites. This network is focused on assessing the statuses of amphibian populations relative to global change and related variables along environmental gradients in the United States and Canada ( www.umesc.usgs.gov/twgcrn.html ). Since we implemented our first network field sites in 2008, our results from using improved recorders and analytical software clearly have demonstrated their value for surveying and monitoring populations of calling amphibians.
To briefly illustrate some of these results, first listen to this five-minute recording we made at a wetland in the St. Croix National Scenic Riverway ( www.nps.gov/sacn/index.htm ) in Minnesota at 11 p.m. on June 7, 2008:
The sounds are dominated by calls from eastern gray treefrogs (Hyla versicolor), with less frequent calls of Cope’s gray treefrogs (H. chrysoscelis) and American toads (Bufo americanus). Figure 1 shows the spectrogram from 0 minutes-11 seconds to 0 minutes-15 seconds of this recording. The calls of eastern gray treefrogs and an American toad are evident in the swath of green and yellow colors spanning approximately 800-4000 Hz on the left axis. The thin band of green color spanning approximately 1600-1800 Hz that first is visible about 12 seconds into the recording is the call of an American toad. The remainder of the sounds represented here are treefrogs. Note that within the broader frequency range of treefrog sounds, the greatest sound intensity (yellow) spanned approximately 2000-2500 Hz and the next most-intense band spanned approximately 800-1400 Hz.
Because we scheduled this recorder to record automatically for five minutes at the top of every hour from early April through early August, we can use a contour plot to examine the frog and toad calls on June 7th within the context of all or a portion of the typical calling season for these species at this site (Figure 2). The colors in this plot indicate relative decibel levels (0 highest, -87 lowest) of sound recorded across frequencies from May 1st through June 30th of 2008. This view illustrates that the calls recorded at 11 p.m. on June 7th occurred on one of the peak calling dates for gray treefrogs and American toads at this site in 2008. It also shows when other peaks occurred. Similarly, one can interpret decibel levels in other unique frequency ranges in terms of sound events for birds, insects, humans, and other sources to characterize the entire soundscape at and near this wetland.
Thus, this relatively simple example demonstrates that we can program digital recorders to record autonomously at regular times in remote locations over an entire season and obtain remarkable recordings of calling amphibians and other sounds. We also can use sophisticated analytical and graphics software to listen to recordings and analyze them to determine if and when amphibians were calling. Using such an integrated acoustic analysis, we can measure species presence and model occupancy over time, compare data with measurements from other sensors to compare calling activity, presence, and occupancy with environmental conditions at different scales, and retain the recordings as part of rich acoustic archives for a site that can be revisited at will. These are remarkable advances in our ability to assess the statuses of populations of calling amphibians at local, regional, and broader scales over time.
News & Stories Endangered Frog Eggs Released to Wild Stream
But these are tiny, gelatinous eggs that belong to Rana muscosa -- the mountain yellow-legged frog (also know as the Sierra Madre yellow-legged frog). And biologists are hiding these eggs in a chilly stream in the James San Jacinto Mountains Reserve near Idyllwild, California, in an ongoing, collaborative effort to preserve this endangered amphibian.
On April 14, researchers from USGS and the San Diego Zoo will release these eggs, which were laid by captive frogs at a zoo laboratory 90 miles away. This field expedition is part of a larger USGS-led partnership to study the Southern California population of the mountain yellow-legged frog, which is federally listed as endangered with only 200 adult frogs remaining in the wild.
USGS Western Ecological Research Center biologists Adam Backlin and Liz Gallegos lead the annual population monitoring and captures of the frogs, while the San Diego Zoo, Los Angeles Zoo and Fresno Chaffee Zoo manage captive breeding programs. The U.S. Fish and Wildlife Service and California Department of Fish and Game are responsible for the frog's management and recovery, and the University of California Reserve System protects some of their new stream homes.
"We're hoping that we also see some maturing frogs from last year's batch of released tadpoles, when we head out to release the eggs on Thursday," says Backlin, who has been preparing the eggs' new home in the 50-degrees-cold stream waters.
The eggs will be placed in a cage made of window screening, and should hatch out tadpoles over the coming weeks. The cage also helps researchers count how many tadpoles actually hatched, and protect them for a little while before they are released to their freedom -- hopefully to survive nature's hazards and grow into adult frogs that help repopulate this dwindling species.
"Researchers and managers know that the San Jacinto Reserve once had a yellow-legged frog population in the mid-1990's," says Backlin, who is based in Irvine. "This particular area is already protected land, closed off from human activities and is easy for us researchers to hike to and monitor. So it seemed a safe location to pick for a reintroduction effort."
Southern California mountain yellow-legged frogs are now only found in the San Gabriel, San Bernardino and San Jacinto mountains. A group of San Gabriels frogs were rescued after the 2009 Station Fire, and those are currently being cared for at the Fresno Chaffee Zoo.
Meanwhile, the Los Angeles Zoo also has a group of San Jacinto frogs, whose latest batch of 500 eggs will be hatched into tadpoles in preparation for a June release.
This project is one of many efforts under the USGS Amphibian Research and Monitoring Initiative, which was chartered by congressional mandate to study the troubling amphibian declines in the U.S. and around the world.
News & Stories Rice Field Herbicide Butachlor Is Toxic to Frog Tadpoles
A recent study published in Ecotoxicology (Liu et al. 2011) examined acute and chronic effects of butachlor on tadpoles of the alpine cricket frog (Fejervarya limnocharis), an Asian species that breeds in rice paddies when they are first flooded. The timing coincides with typical butachlor application regimes, and because of the timing of their breeding behavior cricket frogs can be exposed to higher concentrations of butachlor than other frogs.
Tadpoles were hatched from egg masses collected from paddy fields in Taiwan, and then assigned to treatments of zero, 0.05, 0.1, 0.2, 0.4, 0.8, 1.6 and 3.2 mg/l of butachlor. All concentrations were below the recommended application rate of 4.8 mg/l of butachlor in paddy water. The experiments showed that 0.87 mg/l of butachlor would kill 50% of the tadpoles after 96 hours of exposure -- a concentration far below the recommended application rate.
Although the results suggested that cricket frog tadpoles were less sensitive than other amphibians that breed in rice paddy fields -- such as the narrow-mouthed toad (Microhyla ornata; 0.53 mg/l) and Guenther’s frog (Rana guentheri; 0.74 mg/l) -- the surviving tadpoles still exhibited a range of impacts, including delayed metamorphosis. Also, butachlor was genotoxic to tadpoles; the number of DNA strand breaks in the red blood cells of cricket frog tadpoles increased with increasing butachlor concentrations.
Butachlor likely has widespread negative impacts on many species of amphibians, although the severity depends on each species’ sensitivity, butachlor's short half-life and the pattern and timing of its application. Staggered spraying in adjacent fields may create refugia with lower butachlor concentrations, which adult frogs may be able to detect.
This study was supported by a Taiwan National Science Council Grant. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government. The study is contribution 417 of the USGS Amphibian Research and Monitoring Initiative (ARMI).
For further reading:
Liu Wan-Yi, Wang Ching-Yuh, Wang Tsu-Shing, Gary M. Fellers, Lai Bo-Chi, Kam Yeong-Choy. 2011. Impacts of the Herbicide Butachlor on the Larvae of a Paddy Field Breeding Frog (Fejervarya limnocharis) in Subtropical Taiwan. Ecotoxicology 20(2): 377-394. doi: 10.1007/s10646-010-0589-6 USGS: www.werc.usgs.gov/ProductDetails.aspx
WERC Publication Brief: Rice Field Herbicide Butachlor Is Toxic to Taiwanese Frog Tadpoles. Updated April 2011. www.werc.usgs.gov/ProductDetails.aspx
WERC Point Reyes Field Station. www.werc.usgs.gov/pointreyes
News & Stories Management and monitoring an endangered high-elevation salamander under future climate change. A report from the Structured Decision Making Workshop, January 24-28, 2011, National Conservation Training Center, Shepherdstown, WV, USA
The federally endangered salamander P. shenandoah is found nowhere else on earth except within the boundaries of Shenandoah National Park, and its entire known range consists of approximately 6 square kilometers of high elevation (>900m) forested habitat, distributed across three mountain peaks. It is believed that P. shenandoah has become restricted by competition with the red backed salamander (Plethodon cinereus), which is believed to have expanded from the lowlands with a changing climate since the Pleistocene. P. shenandoah s presence is strongly influenced by elevation and aspect, presumably in relation to temperature and moisture gradients and associated central and southern Appalachian high elevation forest types.
Both temperature and humidity are expected to change in the Mid-Atlantic in the next few decades but the uncertainty among global climate models is large (Polsky et al., 2000). Global climate models generally predict warmer and wetter conditions in the Mid-Atlantic region with an increase in average temperature ranging from 1 to 5 C over the next 10 to 100 years (Hawkins et al., 2011). There is considerable uncertainty in downscaling global climate models to areas in complex mountainous terrain, and these projections need to be refined for the Shenandoah National Park.
We applied a formal, structured process for decision making, which can be summarized as comprised of 5 interrelated parts, addressed in succession, and driven by a focus on values-based objectives. Our objectives include ecological (e.g., P. shenandoah persistence) and procedural (e.g., adhere to park policy) objectives, which we treat as fundamental desires which must be considered simultaneously. For the rapid prototype, we considered four fundamental objectives:
1) Maintain Plethodon shenandoah persistence within Shenandoah National Park
2) Adhere to park policy
3) Maximize public acceptance of management of salamander habitats
4) Minimize cost of management
To link the objectives with a suite of potential management actions identified during the workshop, we are incorporating down-scaled climate data directly into models predicting P. shendandoah occupancy. This will enable us to provide an explicit link between habitat conditions, P. shenandoah and P. cinereus occupancy, and changes in the species’ distributions under future climate scenarios. The resulting model can then be used for assessing population viability under future climate scenarios, considering varying levels of environmental variation, environmental autocorrelation, and competition with P. cinereus. It will also be used to investigate the effects of different management actions and various intensities of these actions on the population persistence of P. shenandoah.
Uncertainty is present in all aspects of this decision problem. The ecology of the species and the expectation of future climate conditions under climate change were two major sources of uncertainty identified during the workshop. The relationship between P. Shenandoah occupancy and persistence, and the effects each management alternative on the persistence of P. shenandoah were identified during the workshop.
We plan to address uncertainty in four ways: first, we are designing a set of experiments which will elucidate the ecology of P. shenandoah, particularly with respect to our expectation about how climate variables (temperature and humidity) may influence competition with P. cinereus. Second, we will combine field observations of temperature and humidity to calibrate downscaled climate models, which will provide site-specific estimates of future climate conditions under a range of likely climate scenarios. Third, we plan to develop a population viability analysis to reduce the uncertainty about the relationship between occupancy and persistence. Finally, we will conduct additional surveys outside of the known distribution, to determine the true range limits of the species. Reducing these uncertainties will help inform the effect that the alternative management actions may have on P. shenandoah occupancy.
News & Stories Meeting Session Highlights ARMI
Presenters, followed by the title of their talks, included: Gary Fellers, Western Ecological Research Center, Point Reyes National Seashore, CA (Population size, survival, longevity, and movements of Rana draytonii, and R. sierrae at two closely monitored sites: tracking population trends); Mike Adams, Forest and Rangeland Ecosystem Science Center, Corvallis, OR (Does the probability of local extinction for northern red-legged frogs relate to introduced fish or bullfrogs?); Nate Chelgren, Forest and Rangeland Ecosystem Science Center, Corvallis, OR (Spatial and temporal variation in the demography of coastal tailed frogs (Ascaphus truei): isolating aquatic from terrestrial stage dynamics); Erin Muths, Fort Collins Science Center, Fort Collins, CO (Compensatory effects of recruitment and survival on population persistence); Tara Chestnut, Oregon Water Science Center, Portland, OR, (The ecology of the amphibian chytrid fungus, Batrachochytrium dendrobatidis in the aquatic environment); Blake Hossack, Northern Rocky Mountain Science Center, Missoula, MT (Wildfire and fragmentation: effects on amphibian populations and associated nematodes); David Pilliod, Forest and Rangeland Ecosystem Science Center, Boise, ID (Introducing an automated pattern recognition program for leopard frogs); and Steve Corn, Northern Rocky Mountain Science Center, Missoula, MT (How well do call indices represent abundance of breeding anurans?).
ARMI is dedicated to developing the next generation of managers and researchers, and has supported the Declining Amphibian Task Force’s seed grant program for several years. The Regional PIs work with technicians, college students and post-docs on projects that give the newer biologists opportunities to stretch their technical skills. ARMI has directly or indirectly supported 24 graduate students, resulting in 14 Ph.D. dissertations and 10 Master’s theses at universities across the country.
ARMI scientists have identified novel diseases, studied the effects of agricultural practices, forest management, invasive species, livestock grazing, and wildfires on the survival of individuals and species richness; predicted possible outcomes of climate change and diagnosed mass mortality events to name only a few of our research activities. ARMI has worked with partners across academia and State and Federal agencies to develop and evaluate management and conservation actions for amphibians. As a result of these projects, ARMI scientists have produced more than 375 publications, including several books, multiple book chapters, and peer reviewed articles in at least 74 different scientific journals.
ARMI looks forward to the next decade of innovative research and exciting collaborations.
After 4 years of surveys, disease testing, and planning specific to this effort, RMNP is collaborating with USGS and the Colorado Division of Wildlife to reintroduce boreal toads to a site on the west side of the Park. The site is typical of historical toad habitat in the park, has only a small population of chorus frogs (Pseudacris maculata), no evidence of the amphibian chytrid, and no fish. Although most of the wetland dries by the end of summer, deeper waters in the middle provide a refuge for late-developing amphibian larvae. Boreal toad tadpoles do not overwinter, and therefore must grow and metamorphose before the onset of freezing temperatures and snow, making this water refugia important.
This year over 14,000 tadpoles were released by a team of over 40 volunteers on June 25th. This exercise involved carrying plastic bags filled with water and about 300 tadpoles per bag up two miles of trail and into the site. The tadpoles were hatched at the Colorado Division of Wildlife’s Native Species Hatchery in Alamosa, Colorado. The parents of these tadpoles were wild caught boreal toads from RMNP.
This effort involved over 40 volunteers including representatives from the Park Service, U.S. Geological Survey, Bureau of Land Management, U.S. Forest Service, Colorado State University, the Colorado Division of Wildlife and non-governmental agencies.
This was Year 1 of the planned three years of tadpole releases for this site. Boreal toads, if they can survive the tadpole stage and successfully metamorphose, take three to four years to reach sexual maturity and return to their natal pond to breed. Tracking these tiny toads is extremely difficult between metamorphosis and their return to the pond. Multiple releases over several years increase the chances that some will survive and return to breed, and is patterned after a successful reintroduction of Natterjack toads in England.
In addition to the tadpoles, seven adult boreal toads, animals that were in excess of those needed for the captive breeding stock at the hatchery, were also released. These animals, four males and 3 females, were released in early summer after receiving a hormone injection to encourage breeding. Each animal was fitted with a radio transmitter and will be tracked 2 to 3 times per week over the summer until autumn when the batteries on the transmitters will be drained.
Tadpoles are generally considered the best lifestage to use for reintroduction efforts; however, releasing adults also can be advantageous. Released adults can act as “sentinels” to detect disease, particularly the amphibian chytrid fungus. Although the site was tested using non-invasive swabs from captured chorus frogs as well as a newer technique to test the water for this fungus, the lack of a positive test does not provide certainty that the site is disease-free. Having adult toads in the habitat gives researchers the opportunity to monitor susceptible animals for the disease over the course of time. Each animal will be tested every week for the amphibian chytrid fungus and, if the organism is found, this information will be used in determining the course of the reintroduction effort. In addition to serving as sentinels for disease, released animals are being followed closely to determine how they respond to their new habitat, how they make use of it, and how far they roam from it – all critical information for other reintroduction efforts with adult amphibians. Information collected on the released adults, such as body temperature and micro-habitat characteristics, is contributing to another collaborative study (Idaho State University and USGS) on boreal toads that is focusing on toad and site temperatures in relation to the amphibian chytrid fungus at sites in Colorado and Wyoming.
Overall, the multi-year reintroduction of tadpoles and adult boreal toads represents an extraordinary example of inter-agency cooperation in working towards the recovery of a state endangered amphibian.
For further reading:
Muths, E., Corn, P.S., Pessier, A.P., and Green, D.E., 2003, Evidence for disease related amphibian decline in Colorado: Biological Conservation, v. 110, p. 357–365.
Muths, E., 2003, Homerange and movements of boreal toads in undisturbed habitats: Copeia, v. 2003, no. 1, p. 161–165.
Denton, J.S., and Beebee, T.J.C., 1996, Habitat occupancy by juvenile natterjack toads (Bufo calamita) on grazed and ungrazed heathland: Herpetological Journal, v. 6, no. 2, p. 49–52.