The first documented outbreak of the amphibian fungal pathogen, Bactrachytrium dendrobatidis (Bd), often simply referred to as "chytrid", first occurred in Australia in 1993 after a mass mortality event involving multiple anuran species. Since that initial outbreak, Bd has been detected in over 350 amphibian species worldwide and has been associated with severe population declines or extinctions. Bd infection rates vary based on species and life stages impacting the skin of adults and the mouthparts of tadpoles with some species not exhibiting clinical symptoms. The fungus spreads across the skin of the amphibian causing it to thicken and impedes the exchange of water, electrolytes and respiratory gases through the skin resulting in sloughing, lethargy, weight loss, and potentially death. Most outbreaks of Bd occur at higher elevations during the cooler months. In the United States, Bd has been detected in 46 out of 50 states with the western part of the country having the highest incidences. The Utah Division of Wildlife Resources (UDWR) has been screening for Bd since August 2001. Seven out of nine native amphibian species have tested positive for Bd between 2001 and 2024 Four species (Arizona toad, Anaxyrus microscaphus; western toad, Anaxyrus boreas; Columbia spotted frog, Rana luteiventris; northern leopard frog, Lithobates pipiens) that have tested positive are listed as Species of Greatest Conservation Need (SGCN) under the Utah Wildlife Action Plan (UWAP). The Columbia Spotted Frog/Least Chub Conservation Team and Western Toad Conservation Team have identified the need to prevent the decline of current breeding sites as well as expanding populations by increasing the number of additional breeding sites using historic breeding sites or finding sites with suitable habitat that could become new breeding sites for these species. Under the UWAP, Bd is identified as a threat to anuran populations in Utah and continued screening throughout the state is important for understanding the prevalence and spread of Bd. Translocations has been discussed as a conservation management tool in both conservation teams. Identifying source sites and recipient sites are important to meet the goals of maintaining current populations while increasing the number of sites on the landscape for SGCN amphibians. Before considering source sites, recipient sites or repatriation sites for translocation or reintroductions, we need to determine Bd status of those sites to be able to make effective management decisions for performing conservation actions that have the best chances of yielding successful results with disease management considerations. Currently, a repatriation plan is being developed by the Western Toad Repatriation Plan Team (WTRPT). The WTRPT have identified the Pausaungunt Plateau as a priority population for a captive breeding and release program. The Pausaungunt Plateau has experienced sharp declines from Bd since the 1990s and we are currently releasing captive bred individuals at a site that has historically tested positive for Bd. Finding a secondary release site that is Bd negative is important to try to maintain a population that consists of the genetics from the Paunsaugunt Plateau and increases the chances of successful repatriation efforts.

The goal of this project is to determine the disease status of 16 sites that have been identified as ideal candidates for translocation projects, source sites for those translocation projects or broodstock considerations, and potential release sites for repatriation efforts. Objective 1: Determine status of Bd at potential source and recipient sites for Columbia spotted frog, northern leopard frog, and western toad. Objective 2: Evaluate the status of Bd in potential secondary sites for the Paunsaugunt Plateau population. Objective 3: Consider if any source sites should be used for broodstocks in the captive breeding program. Objective 4: Develop a protocol for translocating amphibians between sites.

These locations have been identified as potential source, recipient, or repatriation sites that will benefit the populations in the state by using them to increase number of individuals at recipient sites or increase the number of breeding sites for repatriation efforts. There is also a need to identify a secondary release site for the western toad for the Paunsaugunt Plateau captive breeding program and those sites have been selected in areas that have been deemed suitable. Conducting chytrid sampling and testing at these sites now will allow for more effective management decisions for addressing amphibian population conservation efforts in the next couple years where projects have been identified for more immediate intervention.

Chytrid is listed as a potential threat to amphibian SGCNs listed in the UWAP. Maintaining and increasing populations for amphibian SGCNs are objectives in Conservation Strategies and Conservation Teams for Columbia spotted frogs and western toads. This project will result in developing a protocol for amphibian translocations that will be important to incorporate into Conservation Strategies for amphibian SGCNs and the Western Toad Repatriation Plan.

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Chytrid monitoring will be managed by the Utah Division of Wildlife Resources. Field sample collection will be performed by trained UDWR employees.

Objective 1 -- There are 16 sites that require sample collection: 5 potential repatriation sites (one in Central Region, two in Northern Region, and two in Southern Region); 4 potential source sites (two in Central Region, one in Northern Region, and one in Southern Region); 8 potential translocations or recipient sites (two in Central Region, three in Northern Region, and three in Southern Region; two of these sites are also being considered as translocation recipient sites and are not counted twice in total site number); and 1 site that is a new population of Columbia spotted frogs (Central Region). Task 1 --Collect adequate number of samples at each site to have confidence in a negative Bd test result for the entire site. This number has been determined from Skerratt et al. 2008 and Gray et al. 2017. Some sites may not have the focal SGCN present and may require the collection of swabs from non-SGCN amphibians present at the site to increase number of samples. Task 2 -- A fine rayon tipped swab will be passed over the ventral surfaces 20 to 30 times targeting the pelvis patch, toe webbing, and ventral surfaces of the thighs. Place the tip into a screwtop Eppendorf tube and break the tip off into the tube and close the lid. Label the tube with the species, animal ID number, date, and site. Recent studies have shown that nitrile gloves have fungicidal properties. This protocol will include updated recommendations to include the use of non-nitrile gloves. The samples are to be stored at -20 degrees Celsius until they are shipped frozen to Pisces Molecular for PCR. Direct shipping information for Pisces molecular will be included in the collection protocol. At the end of the season, the state herpetologist will request an inventory of samples collected during the spring, summer, and early fall field seasons. Samples may be transported to the Salt Lake Office to be pooled and shipped together or sent directly to Pisces Molecular after contacting the company in advance. Objective 2: Collect eDNA water samples at sites to test for Bd. Task 1 -- Sites that have none or very low number of amphibians for adequate Bd testing will consider collecting eDNA water samples. Task 2 -- Organize borrowing water pumps and associated equipment from the Rocky Mountain Research Station to collect samples at identified sites. The National Genomics Center (NGC) provide field kits with filter cups, supplies, and protocols to collect eDNA samples. The eDNA samples will have to analyzed by NGC in order to borrow eDNA sampling equipment or field kit supplies Objective 3: Develop a protocol for translocating amphibians between sites. Objective 4: Incorporate results into 2025 conservation team management discussions and repatriation planning. Literature Cited: Gray et al. 2017. Pathogen surveillance in herpetofaunal populations: guidance on study design, sample collection, biosecurity, and intervention strategies. Herpetological Review 48(2):334-351. Skerratt et al. 2008. Survey protocol for detecting chytridiomycosis in all Australian frog populations. Dis. Aquat. Org. 80:85-94.

Monitoring will be conducted by UDWR regional biologists and the UDWR native herpetology coordinator.

UDWR regional biologists and native herpetology coordinator, National Park Service, U.S. Forest Service, U.S. Fish and Wildlife Service, Utah's Hogle Zoo, Sageland Collaborative, and private landowners

Chytrid detection and population assessments will inform efforts for repatriation planning for at least three amphibian SGCNs. We will also develop protocols for translocating individuals between sites within the state.

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