Among all vertebrates globally, amphibians are at greatest risk of extinction (Luedtke et al. 2023). Declines in amphibian populations have been driven by habitat degradation and disease, notably amphibian chytridiomycosis (Lips 2016). Effective recovery planning for declining populations requires a better understanding of the impacts of these threats and how those impacts are, or will be, affected by climate change. Found across western North America in montane habitats, populations of the western (boreal) toad (Anaxyrus boreas boreas) have undergone significant declines, notably in the southern Rocky Mountains (Muths et al. 2003; Scherer et al. 2005) and New Mexico, where the species has been extirpated (IUCN SSC Amphibian Specialist Group 2022). In Utah, the western toad is one of five amphibians classified as in greatest need of conservation action. Recovery planning for the western toad in Utah has been hampered by lack of key data. Although some populations have been surveyed since 1994, wildlife managers have a limited understanding of how disease (e.g., chytridiomycosis), environmental factors, invasive species, climate change, and habitat disturbance affect dispersal, breeding, hibernation, habitat use, and disease prevalence in this species. To help close these data gaps and promote evidence-based decision-making, field-based monitoring of individual animals and populations is required. To date, survey data on the western toad have been acquired primarily using traditional field methods. These methods are, however, ill-suited to answer several key questions important to species recovery planning. Several key research questions, such as selection of overwintering microhabitat by toads, cannot be effectively conducted without biotelemetry. Biotelemetry: Overview Biotelemetry is a method that uses animal-borne devices (attached externally or internally) that remotely transmit information to receivers. Advances in biotelemetry have significantly bolstered scientific understanding of wildlife behavior, biology, and ecology. Using biotelemetry techniques, for example, scientists learned that basking sharks do not hibernate -- a misconception perpetuated for 50 years -- but instead migrate seasonally to warmer waters (Skomal et al. 2009), and that climate change is triggering early migration in the American robin (Oliver 2020). Biotelemetry also plays a crucial role in the conservation of threatened species (Cooke 2008). Data from tagged large carnivores have revealed dispersal corridors and sites where these dangerous predators and humans commonly co-occur (Cushman et al. 2018; Naha et al. 2021). Such information has contributed to policy and strategy development intended to reduce human-carnivore conflict. For species reintroductions and translocations, biotelemetry may be essential to effective post-release monitoring and can ultimately facilitate reintroduction success (e.g., Pettit et al. 2017; Hammond et al. 2021). Depending on the types of receivers, transmitters, and signals, biotelemetry can be categorized as PIT (passive integrated transponder), harmonic, radio, satellite, or acoustic. For decades, wildlife researchers and managers have tagged animals using subcutaneous PIT tags paired with radio frequency identification (RFID) receivers. Because PIT tags do not require a power source, they can serve as a lifetime ID tag. However, PIT tags transmit a signal only when they pass very near an RFID receiver: a few centimeters with standard handheld receivers or up to 50cm with long-range receivers (Hammond et al. 2021). Like PIT tags, harmonic devices do not use batteries. Harmonic devices are small, passive reflector (diode) tags paired with handheld receivers. Because harmonic tags are very small, they can be used to track insects and tiny amphibians. Like PIT telemetry, however, the range of harmonic signals is typically less than 15m, meaning receivers must be physically close to detect harmonic tags. Detecting animals at greater ranges requires radio- or satellite telemetry techniques. Radiotelemetry uses Very High Frequency (VHF; 30--300 MHz) or Ultra High Frequency (UHF; 300MHz--3GHz) signals and receivers. Satellite tracking of wildlife uses Global Positioning System (GPS) or ARGOS (Advanced Research and Global Observation Satellite) systems. Over time, radio- and satellite telemetry equipment has become increasingly reliable, smaller, and less expensive. These advancements have allowed scientists and wildlife managers to use this technology with small-bodied taxa. Biotelemetry: Considerations Although biotelemetry techniques have many beneficial applications in wildlife research and conservation, their use with wildlife raises important ethical questions. The potential rewards of biotelemetry are so promising that scientists and wildlife managers have tended to embrace this method without fully understanding the risks to focal species (Balmori 2024; Manville et al. 2024). Biotelemetry is known to cause deleterious changes in animal physiology, movement, reproduction, and behavior, and new concerns are surfacing, such as potential impacts on wildlife health from radiofrequency radiation emitted by telemetry devices (Balmori 2024; Manville et al. 2024). In general, scientists and wildlife managers have been slow to evaluate marking and tagging techniques. When such investigations are conducted, negative (and sometimes unexpected) effects of these techniques on wildlife are often exposed (Murray and Fuller 2000). A review of published research that used telemetry devices to track wildlife found that just a fraction (~10%) of 836 studies tested or directly addressed the impact of radio-transmitters on tagged animals (Godfrey and Bryant 2003). In another review, Altobelli et al. (2022) summarized important insights about amphibian behavior and ecology made with the help of biotelemetry, but also pointed out that transmitters can impair movement and cause pain and mortality in amphibians. They emphasized the importance of prioritizing animal welfare and understanding and minimizing negative impacts of transmitters and modes of attachment. Because researchers often do not reveal the status (e.g., survival) of tagged animals at the end of a study, the actual extent of harmful impacts may be much higher than reported in the literature (Altobelli et al. 2022). This lack of transparency means new studies are likely to continue to repeat prior mistakes. Telemetry has long been used to study and monitor amphibians, but its short- and long-term effects on sensitive species are not well known. Establishing taxon-specific best practices for the use of biotelemetry should involve, at a minimum, reviewing the literature for relevant findings regarding transmitters and attachments, seeking guidance from telemetry manufacturers and researchers with experience tracking the same or closely related species, and weighing whether the expected findings outweigh the risks involved. To date, few investigations of amphibians have evaluated the impact of transmitters and attachment methods on individual animals prior to full deployment in wild populations. Yet, the importance of assessing methodologies should not be overlooked. Global amphibian specialists have identified "methodological improvements for research and monitoring" as one of five emerging research priorities needed to advance amphibian conservation (Campbell Grant et al. 2023). Western (Boreal) Toad Biotelemetry is not new to western toad research. Although PIT telemetry has long been used with this species (e.g., Thompson 2004; Scherer et al. 2005; Schmetterling and Young 2008; Pilliod et al. 2010; Hossack et al. 2020), assessments of the impacts of PIT tagging on individual animals are still emerging. Scherer et al. (2005) found that marking western toads with PIT tags significantly reduced survival rates. They suggested that PIT-tag loss and the adverse effects of the PIT tag itself or the marking process were at least partly responsible for this result. In contrast, Rowley et al. (2024) found that PIT tagging had no deleterious effects on demographic rates in western toads. The authors compared two identification methods, PIT tags and pattern recognition, and evaluated the effects of PIT tagging on demographic rates in a reintroduced population. The study's major finding, combined with 100% PIT-tag retention after 5 years, led the authors to recommend PIT tagging as an identification method in monitoring programs. In a similar investigation, PIT tags and photos were compared as a means of identifying individual toads (Roberts et al. 2021). Initial toad handling time was higher with PIT tags, but the time required to handle previously PIT-tagged individuals was lower. Over a toad's lifetime, monitoring via PIT tags required significantly less handling time than with photo identification (Roberts et al. 2021). Studies such as these provide vital information regarding the pros and cons of methods and technologies for species monitoring programs. PIT tagging is still commonly used by scientists and wildlife managers, but its limitations (e.g., short detection distance) have encouraged the adoption of radiotelemetry in western toad research (e.g., Muths etal. 2003; Schmetterling and Young 2008; Browne and Paszkowski 2010, 2018; Long 2014; Barrile et al. 2021). Just a few of these studies, however, evaluated the effects of the method on individual animals. Often cited is a study by Bartlet and Peterson (2000), who evaluated how a radio-transmitter and belt attachment affected 3 captive and 38 wild western toads. Another study compared two attachment modes: waistband harness and surgical implantation (Long 2014). No studies benefited from working with a larger sample of captive individuals under controlled conditions. In 2008, declining populations of the western toad in Utah led stakeholders to establish a captive assurance colony for one particularly threatened and genetically distinct population (from the Paunsaugunt Plateau in southwestern Utah). This assurance colony is currently managed by five partner institutions, including Utah's Hogle Zoo, Omaha's Henry Doorly Zoo & Aquarium, Denver Zoo Conservation Alliance, Loveland Living Planet Aquarium, and Wahweap fish hatchery. Releases of tadpoles, juveniles, and adults bred in captivity have been, and will continue to be, conducted to support recovery of this species in the state. To date, however, limited monitoring data on released individuals impede a comprehensive evaluation of this reintroduction effort. Post-release monitoring outcomes are critical to understanding the efficacy of reintroductions and ultimately determining success or failure (Linhoff et al. 2021). Given the importance of establishing monitoring protocols for the study and conservation of the western toad, Utah's Hogle Zoo and Omaha's Henry Doorly Zoo propose systematic tests to evaluate the potential effects of biotelemetry in this species and develop best-practice standards for its use. Using the western toad colony at the Omaha Zoo's Amphibian Conservation Center, this project will evaluate how biotelemetry transmitters and attachment methods influence stress levels, mobility, and comfort. Regular monitoring by animal-care and veterinarian staff will ensure that animal wellbeing is prioritized. The design and findings of this study will also inform biotelemetry research on other related amphibian taxa. Literature Cited Altobelli, J.T., Dickinson, K.J.M., Godfrey, S.S., and Bishop, P.J. 2022. Methods in amphibian biotelemetry: two decades in review. Austral Ecology 47: 1382--1395. Balmori, A. 2024. Radio-tracking systems emit pulsed waves that could affect the health and alter the orientation of animals. Journal for Nature Conservation 77: 126520. Gabriel M. Barrile, Chalfoun, A.D., and Walters, A.W. 2021. Infection status as the basis for habitat choices in a wild amphibian. The American Naturalist 197: 128--137. Bartelt, P.E., and C.R. Peterson. 2000. A description and evaluation of a plastic belt for attaching radiotransmitters to western toads (Bufo boreas). Northwestern Naturalist 81: 122--128. Browne, C.I., and Paszkowski, C.A. 2010. Hibernation sites of western toads (Anaxyrus boreas): characterization and management implications. Herpetological Conservation and Biology 5: 49--63. Browne, C.I., and Paszkowski, C.A. 2018. Microhabitat selection by western toads (Anaxyrus boreas). Herpetological Conservation and Biology 13: 317--330. Campbell Grant, E.H., Amburgey, S.M., Gratwicke, B., Acosta-Chaves, V., Belasen, A. M., Bickford, D., et al. 2023. Priority research needs to inform amphibian conservation in the Anthropocene. Conservation Science and Practice 5: e12988. Cooke, S.J. 2008. Biotelemetry and biologging in endangered species research and animal conservation: relevance to regional, national, and IUCN Red List threat assessments. Endangered Species Research 4: 165--185. Cushman, S.A., Elliot, N.B., Bauer, D., Kesch, K., Bahaa-el-din, L., Bothwell, H., et al. 2018. Prioritizing core areas, corridors and conflict hotspots for lion conservation in southern Africa. PLoS ONE 13: e0196213. Godfrey, J.D., and Bryant, D.M. 2003. Effects of radio transmitters: review of recent radio-tracking studies. In: Conservation Applications of Measuring Energy Expenditure of New Zealand Birds: Assessing Habitat Quality and Costs of Carrying Radio Transmitters. Science for Conservation: 83--95. Hammond, T.T., Curtis, M.J., Jacobs, L.E., Tobler, M.W., Swaisgood, R.R., and Shier, D.M. 2021. Behavior and detection method influence detection probability of a translocated, endangered amphibian. Animal Conservation 24: 401--411. Hossack, B.R., Russell, R.E., and McCaffery, R. 2020. Contrasting demographic responses of toad populations to regionally synchronous pathogen (Batrachochytrium dendrobatidis) dynamics. Biological Conservation 241: 108373. IUCN SSC Amphibian Specialist Group. 2022. Anaxyrus boreas. The IUCN Red List of Threatened Species 2022: e.T181488862A197445871. Accessed 1 January 2025. Linhoff, L.J., Soorae, P.S., Harding, G., Donnelly, M.A., Germano, J.M., Hunter, D.A., McFadden, M., Mendelson III, J.R., Pessier, A.P., Sredl, M.J., and Eckstut, M.E. (eds.) 2021. IUCN Guidelines for Amphibian Reintroductions and Other Conservation Translocations, 1st edition. IUCN: Gland, Switzerland. Lips, K.R. 2016. Overview of chytrid emergence and impacts on amphibians. Philosophical Transactions of the Royal Society B 371: 20150465. Long, Z.L. 2014. Tracking Habitat Use by Boreal Toads in Disturbed Forest on the Boreal Plain in Alberta. Master's thesis. Lakehead University: Ontario, Canada. Luedtke, J.A., Chanson, J., Neam, K. et al. 2023. Ongoing declines for the world's amphibians in the face of emerging threats. Nature 622: 308--314. Manville, A.M. II, Levitt, B.B., and Lai, H.C. 2024. Health and environmental effects to wildlife from radio telemetry and tracking devices--state of the science and best management practices. Frontiers in Veterinary Science 11: 1283709. Murray, D.L., and Fuller, M.R. 2000. A critical review of the effects of marking on the biology of vertebrates. In: Research Techniques in Animal Ecology: Controversies and Consequences (L. Boitani and T.K. Fuller, eds.). Columbia University Press, New York: 15--64. Muths, E., Corn, P.S., Pessier, A.P., and Green, D.E. 2003. Evidence for disease related amphibian decline in Colorado. Biological Conservation 110: 357--365. Muths, E., Hossack, B.R., Campbell Grant, E.H., Pilliod, D.S., and Mosher, B.A. 2020. Effects of snowpack, temperature, and disease on demography in a wild population of amphibians. Herpetologica 76: 132--143. Naha, D., Dash, S.K., Kupferman, C., Beasley, J.C., and Sathyakumar, S. 2021. Movement behavior of a solitary large carnivore within a hotspot of human-wildlife conflicts in India. Scientific Reports 11: 3862. Oliver, R.Y., Mahoney, P.J., Gurarie, E., Krikun, N., Weeks, B.C., Hebblewhite, M., Liston, G., and Boelman, N. 2020. Behavioral responses to spring snow conditions contribute to long-term shift in migration phenology in American robins. Environmental Research Letters 15: 045003. Pettit, L., Greenlees, M., and Shine, R. 2017. The impact of transportation and translocation on dispersal behaviour in the invasive cane toad. Oecologia 184: 411--422. Pilliod, D.S., Muths, E., Scherer, R.D., Bartelt, P.E., Corn, P.S., Hossack, B.R., Lambert, B.A., Mccaffery, R., and Gaughan, C. 2010. Effects of amphibian chytrid fungus on individual survival probability in wild boreal toads. Conservation Biology 24: 1259--1267. Roberts, L.S., Feuka, A.B., Muths, E. Hardy, B.M., and Bailey, L.L. 2021. Trade-offs in initial and long-term handling efficiency of PIT-tag and photographic identification methods. Ecological Indicators 130: 108110. Rowley, L.R., Bailey, L.L., and Wright III, F.B. 2024. No measured effect of PIT-tagging on demographic estimates from a reintroduced western toad (Anaxyrus boreas) population. Ichthyology and Herpetology 112 444--451. Scherer, R.D., Muths, E., Noon, B.R., and Corn, P.S. 2005. An evaluation of weather and disease as causes of decline in two populations of boreal toads. Ecological Applications 15: 2150--2160. Schmetterling, D.A., and Young, M.K. 2008. Summer movements of boreal toads (Bufo boreas boreas) in two western Montana basins. Journal of Herpetology 42: 111--123. Skomal, G.B., Zeeman, S.I., Chisholm, J.H., Summers, E.L., Walsh, H.J., McMahon, K.W., and Thorrold, S.R. 2009. Transequatorial migrations by basking sharks in the western Atlantic Ocean. Current Biology 19: 1019--1022. Thompson, P.D. 2004. Observations of boreal toad (Bufo boreas) breeding populations in Northwestern Utah. Herpetological Review 35: 342--344.

The aims of this project are to establish best practices for the use of biotelemetry in western toad research and conservation and to emphasize the importance of animal welfare in studies involving biotelemetry, especially on imperiled amphibians. The objectives are to: * Determine if and how biotelemetry apparatuses affect the mobility of toads; * Determine if and how biotelemetry apparatuses affect stress levels of toads; * Determine if biotelemetry apparatuses cause abrasions or other irritation in toads and, if so, the type and severity of these abrasions; * Compare stress levels, mobility, and comfort between toads with and without biotelemetry apparatuses; * Identify unexpected negative or positive outcomes for toads equipped with biotelemetry apparatuses; * Develop and share widely best-practice guidelines for use of biotelemetry in western (boreal) toads.

This project will be conducted using the western toad colony at the Amphibian Conservation Center at Omaha's Henry Doorly Zoo and Aquarium in Nebraska. Omaha Zoo is one of the five partners in the captive propagation and management program for the Utah western toad. Omaha Zoo currently holds a sufficient number of adult and juvenile toads that can be used as test and control toads. To date, survey data on this species have been acquired primarily using traditional field methods, yet such methods are often ill-suited to answering key questions important to conservation planning. Biotelemetry will create opportunities to increase scientific understanding of this species to aid in its recovery, thus an evaluation of the effective and ethical use of this technique is well justified.

This project aligns with the goals and objectives of the most recent Conservation Agreement for the Western Toad (Anaxyrus boreas) in Utah. A species recovery plan for the western toad is expected in 2026. GOAL 1: Address, classify, and mitigate current and future threats to western toads, and identify new threats This project supports Goal 1 by testing new methodological techniques to promote responsible research of the western toad that helps to close data gaps. The resulting best-practice guidelines will be widely shared among partners. GOAL 2: Maintain, investigate, and implement workable long-term propagation and translocation strategies By testing biotelemetry with this species, this project prepares wildlife managers to effectively use this technique in post-release monitoring efforts. Long-term monitoring is needed to reliably measure the outcomes of reintroduction, supplementation, and translocation initiatives for the western toad. GOAL 3: Maintain existing interagency and Western Toad Conservation Team (WTCT) partnerships and seek out new collaborations The outcome of this project -- best practice standards for use of biotelemetry in the western toad -- will be shared among partners, including DWR regional biologists, the DWR administrative team, and others. Future collaborations on the design of projects using biotelemetry in the western toad strengthens relationships among stakeholders and facilitates communication.

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Not applicable. This project will be conducted following animal wellbeing guidelines of two institutions accredited by the American Association of Zoos and Aquariums (AZA). Utah's Hogle Zoo's Scientific Review Committee and Omaha Zoo's Institutional Animal Care and Use Committee will approve all protocols before the project commences.

This study will measure impacts caused by different biotelemetry transmitters (VHF and harmonic) and attachment methods and materials. The project team will develop health and wellbeing protocols related to behavioral, physical, and physiological impacts. Utah's Hogle Zoo's Scientific Review Committee and Omaha Zoo's Institutional Animal Care and Use Committee will approve all protocols before the project commences. Study toads will be kept in separate tubs designed using substrate materials that mimic the species' natural habitat as much as possible. To quantify and monitor stress, the team will use non-invasive dermal swabs to collect and measure glucocorticoid secretions. Study toads with and without transmitters will be regularly monitored by human observers and cameras. Toads without transmitters will serve as a comparative baseline by which to assess observations. This project will attempt to systematically test for differences between adults/juveniles and males/females. Research Questions Mobility: Does the biotelemetry apparatus appear to hinder movement? For example, do toads with transmitters become entangled in vegetation significantly more often than toads without transmitters? Do heavier or lighter transmitters result in significant differences in mobility? Do differences in antenna length have any notable effect on mobility? Stress: What is the average time required to affix the biotelemetry apparatus (handling time)? What impact does this process have on corticosterone levels? Are corticosterone levels in toads with transmitters significantly different than levels in toads without transmitters? Do corticosterone levels in toads with transmitters decrease, increase, or remain stable over time? Comfort: Does attachment type (belt, glue) or material type (polyethylene/silicon tubing, beaded chain) cause abrasions or lesions, and if so, to what extent? Does the tightness of the attachment influence whether abrasions occur and to what extent? Do loose-fitting attachments tend to slip down or slip off and thus hinder movement? The project team will develop metrics to assess abrasions and fit.

Project success is assessed by sample sizes and outcomes of tests that result in evidence-based guidelines for use of this technology in the western (boreal) toad (i.e., final publication and distribution of best-practice standards).

Declining populations of the western toad in Utah led to the establishment in 2008 of a captive assurance colony comprising individuals from a highly threatened population from the Paunsaugunt Plateau, southwestern Utah. The assurance colony is managed by five partner institutions, including Utah's Hogle Zoo, Omaha's Henry Doorly Zoo and Aquarium, Denver Zoo Conservation Alliance, Loveland Living Planet Aquarium, and Wahweap fish hatchery. These institutions collaborate in the captive management of this species, including breeding, husbandry, health, and reintroduction. For the past decade, Hogle Zoo has also partnered with the Utah Division of Wildlife Resources, Sageland Collaborative, Utah Geological Survey, U.S. Forest Service, and the Bureau of Land Management to monitor western toad populations and habitats and cooperate in recovery planning efforts for this species.

Over time, as biotelemetry is increasingly used to monitor the western toad and related taxa, we expect the best-practice protocols to be further evaluated in the field in natural conditions. New insights gained from the ongoing application of this technique can be integrated into revisions of the standards and shared among partners.

Not applicable