New paper! Two Sierra frogs, different fates.
We are excited to share a new paper published today in the ESA’s open access journal Ecosphere! MLRG alum Kira Miller conducted this research project during her masters graduate work. In short, Kira surveyed a large number of lakes to capture Rana sierrae/muscosa (mountain yellow-legged frogs) and Pseudacris regilla (Pacific chorus frogs), and we compared the microbiome and Bd infection intensities of both hosts in sites where they co-occurred and where each occurred in isolation. Read more using the PDF or link below. Congratulations Kira!
Miller, Kira M., Thomas C. Smith, Andrea J. Jani, Andrew G. Zink, and Vance T. Vredenburg. 2026. Differential Skin Microbiomes and Disease Outcomes in Sympatric Hosts Despite Similar Infection Burdens. Ecosphere 17(10): e70794. [PDF] https://doi-org.proxy.library.ucsb.edu/10.1002/ecs2.70794
Shout out of gratitude to other MLRG members, alumni, and collaborators who contributed to various parts of this project: Alexa Lindauer, Sage Lee, Sara Dykman, and Sam Lapp, and to SNARL for logistical support and laboratory space. This project was partially funded through the RIBBiTR Biology Integration Institute.



2024 MLRG Annual Newsletter
Sierra Nevada yellow-legged frog recovery in the news!
Roland, Tom, and colleagues Max Joseph (Planet, CU Boulder ), Mark Wilber (U. Tennesee), and Rob Grasso (Yosemite National Park) are celebrating new work just published in Nature Communications! This article synthesizes decades of frog recovery work, including frog translocations, capture-mark-recapture population studies, disease quantification, and mathematical modeling. Take away: frogs in Yosemite have adapted to live with Batrachochytrium dendrobatidis, and that evolution can be leveraged to facilitate recovery on a landscape scale. Read the full article here:
https://www.nature.com/articles/s41467-024-53608-4

This article has captivated the press. Here are some examples:
– UCSB press release
– USA Today
– San Francisco Chronicle
This tremendous effort would not have been possible without our amazing field teams over the past two decades, and the recent support of Alexa Lindauer managing our laboratory and data! Thanks everyone!
2023 MLRG Annual Newsletter
Science and conservation together: why frog reintroductions work
After an 18 year study on reestablishing mountain yellow-legged frogs in the Sierra Nevada, we are proud to share a success story in amphibian conservation (covered by New Scientist [PDF]). The key to our success? Frog evolution and two decades of collaboration among academic, non-profit, and agency scientists.

Mountain yellow-legged (MYL) frogs are endangered due to (1) the introduction of non-native trout into their largely fishless habitat, and (2) the invasion of the novel amphibian fungal pathogen, Batrachochytrium dendrobatidis (Bd) in the Sierra. While trout can be removed from some MYL frog habitats, resulting in rapid recovery of frog populations, Bd cannot be removed from the landscape. As such, MYL frogs must overcome the pressures of this pathogen to recover.
Although most MYL frog populations experience local extinction after a Bd outbreak, some populations persist despite ongoing Bd infections. Frogs in these populations show increased resistance to Bd (i.e. the ability to limit the severity of Bd infection). In a new study, we show that a) this resistance is the result of evolution in frogs, and b) we can leverage this evolution of resistance to Bd to recover MYL frogs through reintroductions. By reintroducing resistant frogs into habitats they formerly occupied, we can reestablish MYL frogs in the presence of Bd across their historical range. Armed with this powerful recovery tool, we will require multi-agency collaboration, patience, and adequate funding to continue reestablishing MYL frogs throughout the Sierra.



2022 MLRG Annual Wrap-up and Newsletter
Our annual newsletter highlights our 2022 accomplishments in frog recovery, disease ecology research, and mentoring of next-generation scientists! This year, our newsletter shares their voices and views on working in wilderness, learning research skills, and being part of an ongoing conservation project. In short, it takes a village. You can learn how we fund mountain-yellow legged frog recovery, and how you can help (like donating your used smartphone!). A big thank you to our hard-working technicians, the staff at UC Santa Barbara Earth Research Institute and the Sierra Nevada Aquatic Research Lab, and all of our agency partners in frog conservation for a successful season!
<click here to read the newsletter>

Photo credit: Sara Dykman 2022
2022 Publications
Here are some of the papers that MLRG members contributed to in 2022:
[PDF] Host density has limited effects on pathogen invasion, disease-induced declines, and within-host infection dynamics across a landscape of disease. Journal of Animal Ecology.
Wilber, M. Q., R. A. Knapp, T. C. Smith, and C. J. Briggs.
[PDF] Rana sierrae (Sierra Nevada Yellow-legged Frog). Behavior and Diet. Herpetological Review. Smith, T. C., R. A. Knapp, J. Imperato, K. Miller, and D. Rose.
[link] Effectiveness of antifungal treatments during chytridiomycosis epizootics in populations of an endangered frog. PeerJ. Knapp, R. A., M. B. Joseph, T. C. Smith, E. E. Hegeman, V. T. Vredenburg, J. E. Erdman Jr, D. M. Boiano, A. J. Jani, and C. J. Briggs.
[PDF] Localized carry‐over effects of pond drying on survival, growth, and pathogen defenses in amphibians. Ecosphere. Le Sage, E.H., Ohmer, M.E., LaBumbard, B.C., Altman, K.A., Reinert, L.K., Bednark, J.G., Bletz, M.C., Inman, B., Lindauer, A., McDonnell, N.B., Parker, S.K. Skerlac S.M., Wantman, T., Rollins-Smith, L.A., Woodhams, D.C., Voyles, J., and Richards-Zawacki, C.L.
NSF-funded Biology Integration Institute to study amphibian resilience to disease
We are excited to be team members of a newly-funded National Science Foundation Biology Integration Institute called RIBBiTR (Resilience Institute Bridging Biological Training and Research). Working with a large and collaborative team of scientists and educators located around the country and conducting research around the globe, we will work toward uncovering mechanisms of amphibian resilience to infectious disease and global change. Read more on the RIBBiTR website and from The Current at UC Santa Barbara.
2021 Newsletter
Check out our 2021 field season accomplishments in our annual newsletter. In addition to summarizing our recovery activities, we also provide an in depth description of what a mountain yellow-legged frog reintroduction entails. In short, it takes a village. Read on in the newsletter to learn how we fund mountain-yellow legged frog recovery, and how you can help (like donating your used smartphone!). A big thank you to our hard-working technicians, the staff at UC Santa Barbara Earth Research Institute and the Sierra Nevada Aquatic Research Lab, and all of our partners in frog conservation for a successful season.

Happy Giving Tuesday, donate your unused smartphone!
Instead of sitting forgotten in a desk drawer, your old smartphone could play a critical role in endangered species recovery and mountain lakes research. The Mountain Lakes Research Group uses smartphones for recording data in the field. Compared to entering data on paper, entering data in smartphones increases efficiency and reduces errors, saving us time and money. Our current smartphones are still chugging along, but we are in need of updating and growing our fleet. Read instructions here to see if your old smartphone could be eligible for donation (spoiler alert, it probably is).

Two new papers published!
One paper (Jani et al. 2021) describes how infection of mountain yellow-legged frogs by the amphibian chytrid fungus causes long-term changes to the community of bacteria inhabiting the frogs’ skin (“microbiome”). Given the myriad roles played by the microbiome, including those related to immunity, changes to its structure could have additional impacts on frogs. The second paper (Joseph and Knapp 2021) shows how using the results of visual encounter surveys in analysis of mark-recapture data can improve estimates of population size. Links to the full text of both papers is available on the Publications page.
New publication: Sierra Lakes Inventory Project data.
Exciting news: we just pushed the Sierra Lakes Inventory Project data set to the Environmental Data Initiative data portal! Roland Knapp ran the SLIP project from 1995-2002 and collected data on >8,000 Sierra Nevada water bodies. We owe Claire Pavelka our gratitude for making this data publication a reality. Claire was a fellow with the Environmental Data Initiative summer data science fellowship program in 2020.
Link to the dataset here.
Citation:
Knapp, R.A., C. Pavelka, E.E. Hegeman, and T.C. Smith. 2020. The Sierra Lakes Inventory Project: Non-Native fish and community composition of lakes and ponds in the Sierra Nevada, California ver 2. Environmental Data Initiative. https://doi.org/10.6073/pasta/d835832d7fd00d9e4466e44eea87fab3
2020 Annual Newsletter
Read up on highlights from the field season and critical results from a long-term frog recovery project in our annual newsletter. Also learn how we fund mountain-yellow legged frog recovery, and how you can help. 2020 has been quite the year, and we send a big thank you to our partners who helped make our work possible during the COVID-19 pandemic and an historic wildfire season.

Mountain yellow-legged frog restoration amid a wildlife pandemic.
California’s mountain yellow-legged frogs are endangered. One reason is an ongoing wildlife pandemic (or, a panzootic). Worldwide, amphibians are threatened by a disease called chytridiomycosis, caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis. This disease has caused declines in frog and salamander species across six continents, including here in California. In a public seminar on Thursday 12 November 2020, our own Mountain Lakes Research Group Principal Investigator Tom Smith, PhD described some of the conservation tools that we study. Our goal is to help mountain yellow-legged frog populations persist in a landscape with widespread disease.
The recorded seminar is available to watch:
https://www.youtube.com/channel/UCRKf_rnxbSEvv_dp5lZtPBQ
This seminar was part of the UC Santa Barbara Natural Reserve System seminar series. Our research group is based out of the Sierra Nevada Aquatic Research Laboratory, which is part of the Natural Reserve System.
Researchers and agencies work together to stop Bd epizootics in wild mountain yellow-legged frog populations.
Our work on Bd mitigation and cooperation with California and U.S. wildlife agencies was recently described on U.S. Fish and Wildlife Service’s blog, in a series on conservation in action. Thanks to Meghan Snow for the write-up, and to Jill Seymour, Isaac Chellman, and many others for their collaboration on this project. See the link below:

Technology aids conservation: Observing frog behavior in frozen lakes using ROVs.
“What do frogs do in winter?” That is a question we hear frequently. Meters-thick ice covers high elevation Sierra Nevada lakes for about nine months of the year. For an animal that spends summer days lounging on rocks in the sun, winter imposes a radical shift in lifestyle. But historically, we could not document frog winter behavior through direct observation. Although scuba diving allows observation of some taxa, winter ice, elevation, and remoteness prevent us from diving in Sierra lakes.
Enter David Lang and his team, who developed the Trident underwater drone at OpenROV and Sofar Ocean Technologies. Over the past few years, our team used a Trident to search for frogs in a frozen lake. This technology allowed us to find frogs and tadpoles, and to capture video to document their overwintering behavior. David and some of his colleagues joined us at our study lake on two late winter expeditions and experienced our “eureka” moments in which we saw frogs and tadpoles as never before. Through the lens of the Trident and the VR goggles, we finally saw the frog’s eye view of life under the ice.
In his recent OneZero article, David describes how the Trident makes this project possible. More generally, he explores the potential for tech to enhance conservation projects. We are happy to see David’s story published, and honored that he focused on our project. Read his story here.

2018 Mountain Lakes Research Group newsletter
We recently sent out our annual Mountain Lakes Research Group newsletter in which we summarize the highlights from our our research and conservation-related activities in 2018. We also discuss the funding challenges that we face, exacerbated by the prolonged shutdown of the federal government, and our fundraising plans for the future. If you would like to receive future newsletters, please let us know.
Story on how scientists transport animals
The Conversation recently published a story about how scientists move butterflies, sea turtles, and frogs as part of conservation-related activities. The section on frogs features mountain yellow-legged frogs and was written by Mountain Lakes Research Group team member, Roland Knapp. Have a look.
New issue of Yosemite Nature Notes
The latest release in the Yosemite Nature Notes video series features the Sierra Nevada yellow-legged frog and describes ongoing efforts to recover this species in Yosemite National Park. Check it out.
