1
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Waddle AW, Clulow S, Aquilina A, Sauer EL, Kaiser SW, Miller C, Flegg JA, Campbell PT, Gallagher H, Dimovski I, Lambreghts Y, Berger L, Skerratt LF, Shine R. Hotspot shelters stimulate frog resistance to chytridiomycosis. Nature 2024; 631:344-349. [PMID: 38926575 DOI: 10.1038/s41586-024-07582-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 05/17/2024] [Indexed: 06/28/2024]
Abstract
Many threats to biodiversity cannot be eliminated; for example, invasive pathogens may be ubiquitous. Chytridiomycosis is a fungal disease that has spread worldwide, driving at least 90 amphibian species to extinction, and severely affecting hundreds of others1-4. Once the disease spreads to a new environment, it is likely to become a permanent part of that ecosystem. To enable coexistence with chytridiomycosis in the field, we devised an intervention that exploits host defences and pathogen vulnerabilities. Here we show that sunlight-heated artificial refugia attract endangered frogs and enable body temperatures high enough to clear infections, and that having recovered in this way, frogs are subsequently resistant to chytridiomycosis even under cool conditions that are optimal for fungal growth. Our results provide a simple, inexpensive and widely applicable strategy to buffer frogs against chytridiomycosis in nature. The refugia are immediately useful for the endangered species we tested and will have broader utility for amphibian species with similar ecologies. Furthermore, our concept could be applied to other wildlife diseases in which differences in host and pathogen physiologies can be exploited. The refugia are made from cheap and readily available materials and therefore could be rapidly adopted by wildlife managers and the public. In summary, habitat protection alone cannot protect species that are affected by invasive diseases, but simple manipulations to microhabitat structure could spell the difference between the extinction and the persistence of endangered amphibians.
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Affiliation(s)
- Anthony W Waddle
- Melbourne Veterinary School, University of Melbourne, Werribee, Victoria, Australia.
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia.
- Applied BioSciences, Macquarie University, Sydney, New South Wales, Australia.
| | - Simon Clulow
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Amy Aquilina
- Melbourne Veterinary School, University of Melbourne, Werribee, Victoria, Australia
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Erin L Sauer
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Shannon W Kaiser
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Claire Miller
- School of Mathematics and Statistics, University of Melbourne, Parkville, Victoria, Australia
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Jennifer A Flegg
- School of Mathematics and Statistics, University of Melbourne, Parkville, Victoria, Australia
| | - Patricia T Campbell
- Department of Infectious Diseases, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Harrison Gallagher
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Ivana Dimovski
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Yorick Lambreghts
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Lee Berger
- Melbourne Veterinary School, University of Melbourne, Werribee, Victoria, Australia
| | - Lee F Skerratt
- Melbourne Veterinary School, University of Melbourne, Werribee, Victoria, Australia
| | - Richard Shine
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
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2
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Chew A, West M, Berger L, Brannelly LA. The impacts of water quality on the amphibian chytrid fungal pathogen: A systematic review. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13274. [PMID: 38775382 PMCID: PMC11110485 DOI: 10.1111/1758-2229.13274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 04/06/2024] [Indexed: 05/25/2024]
Abstract
The pathogenic fungus Batrachochytrium dendrobatidis has caused declines of amphibians worldwide. Yet our understanding of how water quality influences fungal pathogenicity is limited. Here, we reviewed experimental studies on the effect of water quality on this pathogen to determine which parameters impacted disease dynamics consistently. The strongest evidence for protective effects is salinity which shows strong antifungal properties in hosts at natural levels. Although many fungicides had detrimental effects on the fungal pathogen in vitro, their impact on the host is variable and they can worsen infection outcomes. However, one fungicide, epoxiconazole, reduced disease effects experimentally and likely in the field. While heavy metals are frequently studied, there is weak evidence that they influence infection outcomes. Nitrogen and phosphorous do not appear to impact pathogen growth or infection in the amphibian host. The effects of other chemicals, like pesticides and disinfectants on infection were mostly unclear with mixed results or lacking an in vivo component. Our study shows that water chemistry does impact disease dynamics, but the effects of specific parameters require more investigation. Improving our understanding of how water chemistry influences disease dynamics will help predict the impact of chytridiomycosis, especially in amphibian populations affected by land use changes.
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Affiliation(s)
- Adeline Chew
- School of BiosciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Matt West
- School of BiosciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Lee Berger
- Melbourne Veterinary SchoolThe University of MelbourneWerribeeVictoriaAustralia
| | - Laura A. Brannelly
- Melbourne Veterinary SchoolThe University of MelbourneWerribeeVictoriaAustralia
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3
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Berger L, Skerratt LF, Kosch TA, Brannelly LA, Webb RJ, Waddle AW. Advances in Managing Chytridiomycosis for Australian Frogs: Gradarius Firmus Victoria. Annu Rev Anim Biosci 2024; 12:113-133. [PMID: 38358840 DOI: 10.1146/annurev-animal-021122-100823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Extensive knowledge gains from research worldwide over the 25 years since the discovery of chytridiomycosis can be used for improved management. Strategies that have saved populations in the short term and/or enabled recovery include captive breeding, translocation into disease refugia, translocation from resistant populations, disease-free exclosures, and preservation of disease refuges with connectivity to previous habitat, while antifungal treatments have reduced mortality rates in the wild. Increasing host resistance is the goal of many strategies under development, including vaccination and targeted genetic interventions. Pathogen-directed strategies may be more challenging but would have broad applicability. While the search for the silver bullet solution continues, we should value targeted local interventions that stop extinction and buy time for evolution of resistance or development of novel solutions. As for most invasive species and infectious diseases, we need to accept that ongoing management is necessary. For species continuing to decline, proactive deployment and assessment of promising interventions are more valid than a hands-off, do-no-harm approach that will likely allow further extinctions.
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Affiliation(s)
- Lee Berger
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Tiffany A Kosch
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Laura A Brannelly
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Rebecca J Webb
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Anthony W Waddle
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
- Applied Biosciences, Macquarie University, Sydney, New South Wales, Australia;
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4
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Callen A, Pizzatto L, Stockwell MP, Clulow S, Clulow J, Mahony MJ. The effect of salt dosing for chytrid mitigation on tadpoles of a threatened frog, Litoria aurea. J Comp Physiol B 2023; 193:239-247. [PMID: 36811723 PMCID: PMC9992028 DOI: 10.1007/s00360-023-01479-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/10/2023] [Accepted: 02/09/2023] [Indexed: 02/24/2023]
Abstract
The novel fungal pathogen Batrachochytrium dendrobatidis (chytrid) is one of the greatest threats to amphibians worldwide. Small increases in water salinity (up to ca. 4 ppt) have been shown to limit chytrid transmission between frogs, potentially providing a way to create environmental refugia to reduce its impact at a landscape scale. However, the effect of increasing water salinity on tadpoles, a life stage confined to water, is highly variable. Increased water salinity can lead to reduced size and altered growth patterns in some species, with flow-on effects to vital rates such as survival and reproduction. It is thus important to assess potential trade-offs caused by increasing salinity as a tool to mitigate chytrid in susceptible frogs. We conducted laboratory experiments to examine the effects of salinity on the survival and development of tadpoles of a threatened frog (Litoria aurea), previously demonstrated as a suitable candidate for trialling landscape manipulations to mitigate chytrid. We exposed tadpoles to salinity ranging from 1 to 6 ppt and measured survival, time to metamorphosis, body mass and locomotor performance of post-metamorphic frogs as a measure of fitness. Survival and time to metamorphosis did not differ between salinity treatments or controls reared in rainwater. Body mass was positively associated with increasing salinity in the first 14 days. Juvenile frogs from three salinity treatments also showed the same or better locomotor performance compared to rainwater controls, confirming that environmental salinity may influence life history traits in the larval stage, potentially as a hormetic response. Our research suggests that salt concentrations in the range previously shown to improve survival of frogs in the presence of chytrid are unlikely to impact larval development of our candidate threatened species. Our study lends support to the idea of manipulating salinity to create environmental refugia from chytrid for at least some salt-tolerant species.
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Affiliation(s)
- Alex Callen
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia.
| | - Ligia Pizzatto
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Michelle P Stockwell
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Simon Clulow
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, ACT, 2617, Australia
| | - John Clulow
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Michael J Mahony
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
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5
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Jones R, Bourn NAD, Maclean IMD, Wilson RJ. Landscape‐scale dynamics of a threatened species respond to local‐scale conservation management. OIKOS 2023. [DOI: 10.1111/oik.09334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Rachel Jones
- Environment & Sustainability Inst., Univ. of Exeter Cornwall UK
- Butterfly Conservation, Manor Yard East Lulworth Dorset UK
| | | | | | - Robert J. Wilson
- Environment & Sustainability Inst., Univ. of Exeter Cornwall UK
- Museo Nacional de Ciencias Naturales (MNCN‐CSIC) Madrid Spain
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6
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Bolom‐Huet R, Pineda E, Andrade‐Torres A, Díaz‐Fleischer F, Muñoz AL, Galindo‐González J. Chytrid prevalence and infection intensity in treefrogs from three environments with different degrees of conservation in Mexico. Biotropica 2022. [DOI: 10.1111/btp.13186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- René Bolom‐Huet
- Centro de Investigaciones en Ciencias Biológicas Aplicadas Universidad Autónoma del Estado de México Toluca Estado de México Mexico
- Universidad Veracruzana – Instituto de Biotecnología y Ecología Aplicada (INBIOTECA) Xalapa, Veracruz Mexico
| | - Eduardo Pineda
- Instituto de Ecologia – Red de Biología y Conservación de Vertebrados Xalapa, Veracruz Mexico
| | - Antonio Andrade‐Torres
- Universidad Veracruzana – Instituto de Biotecnología y Ecología Aplicada (INBIOTECA) Xalapa, Veracruz Mexico
| | - Francisco Díaz‐Fleischer
- Universidad Veracruzana – Instituto de Biotecnología y Ecología Aplicada (INBIOTECA) Xalapa, Veracruz Mexico
| | - Antonio L. Muñoz
- ECOSUR – Conservación de la Biodiversidad San Cristobal de las Casas, Chiapas Mexico
| | - Jorge Galindo‐González
- Universidad Veracruzana – Instituto de Biotecnología y Ecología Aplicada (INBIOTECA) Xalapa, Veracruz Mexico
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7
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Efficacy of Plant-Derived Fungicides at Inhibiting Batrachochytrium salamandrivorans Growth. J Fungi (Basel) 2022; 8:jof8101025. [PMID: 36294589 PMCID: PMC9605044 DOI: 10.3390/jof8101025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/23/2022] [Accepted: 09/27/2022] [Indexed: 11/21/2022] Open
Abstract
The emerging fungal amphibian pathogen, Batrachochytrium salamandrivorans (Bsal), is currently spreading across Europe and given its estimated invasion potential, has the capacity to decimate salamander populations worldwide. Fungicides are a promising in situ management strategy for Bsal due to their ability to treat the environment and infected individuals. However, antifungal drugs or pesticides could adversely affect the environment and non-target hosts, thus identifying safe, effective candidate fungicides for in situ treatment is needed. Here, we estimated the inhibitory fungicidal efficacy of five plant-derived fungicides (thymol, curcumin, allicin, 6-gingerol, and Pond Pimafix®) and one chemical fungicide (Virkon® Aquatic) against Bsal zoospores in vitro. We used a broth microdilution method in 48-well plates to test the efficacy of six concentrations per fungicide on Bsal zoospore viability. Following plate incubation, we performed cell viability assays and agar plate growth trials to estimate the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of each fungicide. All six fungicides exhibited inhibitory and fungicidal effects against Bsal growth, with estimated MIC concentrations ranging from 60 to 0.156 μg/mL for the different compounds. Allicin showed the greatest efficacy (i.e., lowest MIC and MFC) against Bsal zoospores followed by curcumin, Pond Pimafix®, thymol, 6-gingerol, and Virkon® Aquatic, respectively. Our results provide evidence that plant-derived fungicides are effective at inhibiting and killing Bsal zoospores in vitro and may be useful for in situ treatment. Additional studies are needed to estimate the efficacy of these fungicides at inactivating Bsal in the environment and treating Bsal-infected amphibians.
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8
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Scheele BC, Hollanders M, Hoffmann EP, Newell DA, Lindenmayer DB, McFadden M, Gilbert DJ, Grogan LF. Conservation translocations for amphibian species threatened by chytrid fungus: A review, conceptual framework, and recommendations. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.524] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Ben C. Scheele
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
| | - Matthijs Hollanders
- Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
| | - Emily P. Hoffmann
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
- School of Biological Sciences The University of Western Australia Crawley Western Australia Australia
| | - David A. Newell
- Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
| | - David B. Lindenmayer
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
| | - Michael McFadden
- Taronga Conservation Society Australia Mosman New South Wales Australia
| | - Deon J. Gilbert
- Wildlife Conservation and Science Zoos Victoria Parkville Victoria Australia
| | - Laura F. Grogan
- Centre for Planetary Health and Food Security, School of Environment and Science Griffith University Southport Queensland Australia
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9
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Beranek CT, Maynard C, McHenry C, Clulow J, Mahony M. Rapid population increase of the threatened Australian amphibian Litoria aurea in response to wetlands constructed as a refuge from chytrid-induced disease and introduced fish. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 291:112638. [PMID: 33962282 DOI: 10.1016/j.jenvman.2021.112638] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/24/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Amphibians have declined due to multiple impacts including invasive fish and the disease chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Wetland restoration can be used to increase amphibian populations. However the design of created wetlands must account for threats such as Bd and introduced fish. There have been no attempts on a landscape level to manage these threats with habitat design. Here we monitored the green and golden bell frog (Litoria aurea) in 2.6 ha of constructed wetlands designed to enhance breeding and increase survival through passive mitigation of Bd and exotic fish. We compared the fecundity, adult population sizes, introduced fish occupancy, Bd prevalence and survival rates of frogs in created wetlands (CW) to three control sites to determine if and why the habitat design was successful. Monitoring involved weekly capture-recapture during the austral spring and summer for three L. aurea breeding seasons. We hypothesised that (1) if the CWs were successful in passively limiting fish colonisation, a larger number of breeding events would be detected compared to control sites which are known to be widely colonised by introduced fish. (2) If the wetlands were successful in passively mitigating Bd, then we would observe an equal or greater survival rate and equal to or lower Bd prevalence compared to control wetlands. We observed a 3.3-fold increase in adult population size in CW from season 1 to 2, and the population increased further in season 3.We found strong support for hypothesis (1) and weak support for (2). Based on these results, we conclude that this design was beneficial shortly after their formation primarily due to fish exclusion, but further study is required to determine if these benefits extend long-term. Future amphibian restoration studies are needed to improve the design of wetlands to enhance suppression of Bd.
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Affiliation(s)
- Chad T Beranek
- Conservation Science Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia; FAUNA Research Alliance, PO Box 5092, Kahibah, NSW, 2290, Australia.
| | - Cassandra Maynard
- Conservation Science Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - Colin McHenry
- Conservation Science Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia; FAUNA Research Alliance, PO Box 5092, Kahibah, NSW, 2290, Australia
| | - John Clulow
- Conservation Science Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia; FAUNA Research Alliance, PO Box 5092, Kahibah, NSW, 2290, Australia
| | - Michael Mahony
- Conservation Science Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
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10
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TEMPERATURE AS A DRIVER OF THE PATHOGENICITY AND VIRULENCE OF AMPHIBIAN CHYTRID FUNGUS BATRACHOCHYTRIUM DENDROBATIDIS: A SYSTEMATIC REVIEW. J Wildl Dis 2021; 57:477-494. [PMID: 34019674 DOI: 10.7589/jwd-d-20-00105] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/10/2021] [Indexed: 11/20/2022]
Abstract
Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is a leading cause of global amphibian declines. Severe infections with Bd can lead to cardiac arrest, and mass deaths during epidemics have been reported. Temperature, pH, salinity, and moisture are important determinants of the survival, growth, reproduction, and pathogenicity of Bd, as well as its effect on amphibian populations. Here, we synthesize current knowledge on the role of temperature as a driver of the pathogenicity and virulence of Bd to better understand the effects of temperature on amphibian defense mechanisms against infection. This review advises on research direction and management approaches to benefit amphibian populations affected by Bd. We conclude by offering guidelines for four levels of temperature monitoring in amphibian field studies to improve consistency between studies: regional climate, habitat, microhabitat, and amphibian host.
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11
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HIGHER INFECTION PREVALENCE IN AMPHIBIANS INHABITING HUMAN-MADE COMPARED TO NATURAL WETLANDS. J Wildl Dis 2021; 56:823-836. [PMID: 33600598 DOI: 10.7589/2019-09-220] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/21/2020] [Indexed: 11/20/2022]
Abstract
It is unclear how suitable human-made wetlands are for supporting wildlife and how they impact wildlife disease risk. Natural wetlands (those that were created without human actions) can support more diverse and resilient communities that are at lower risk of disease outbreaks. We compared frog community composition and infection with the pathogenic fungus Batrachochytrium dendrobatidis (Bd) between human-made and natural wetlands in Tippecanoe County, Indiana, US. We conducted visual encounter surveys of frog communities and quantified Bd infection prevalence at four natural and five human-made wetlands. Water parameters associated with human practices (e.g., pH, salinity) and surrounding land use were also compared across sites. We found higher Bd infection prevalence at human-made sites than at natural sites, with monthly differences showing highest infection in spring and fall, and decreasing infection with increasing water temperature. However, we found no differences between human-made and natural sites regarding amphibian community composition, water quality, or surrounding land use. Further, we found frog density increased with distance to nearest roads among both human-made and natural sites. These findings might suggest that human-made wetlands can support frog communities similar to natural wetlands, but pose a greater risk of Bd infection.
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12
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Brannelly LA, McCallum HI, Grogan LF, Briggs CJ, Ribas MP, Hollanders M, Sasso T, Familiar López M, Newell DA, Kilpatrick AM. Mechanisms underlying host persistence following amphibian disease emergence determine appropriate management strategies. Ecol Lett 2020; 24:130-148. [PMID: 33067922 DOI: 10.1111/ele.13621] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/18/2020] [Accepted: 09/08/2020] [Indexed: 12/19/2022]
Abstract
Emerging infectious diseases have caused many species declines, changes in communities and even extinctions. There are also many species that persist following devastating declines due to disease. The broad mechanisms that enable host persistence following declines include evolution of resistance or tolerance, changes in immunity and behaviour, compensatory recruitment, pathogen attenuation, environmental refugia, density-dependent transmission and changes in community composition. Here we examine the case of chytridiomycosis, the most important wildlife disease of the past century. We review the full breadth of mechanisms allowing host persistence, and synthesise research on host, pathogen, environmental and community factors driving persistence following chytridiomycosis-related declines and overview the current evidence and the information required to support each mechanism. We found that for most species the mechanisms facilitating persistence have not been identified. We illustrate how the mechanisms that drive long-term host population dynamics determine the most effective conservation management strategies. Therefore, understanding mechanisms of host persistence is important because many species continue to be threatened by disease, some of which will require intervention. The conceptual framework we describe is broadly applicable to other novel disease systems.
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Affiliation(s)
- Laura A Brannelly
- Veterinary BioSciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Vic, 3030, Australia
| | - Hamish I McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Laura F Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia.,Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Maria P Ribas
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia.,Wildlife Conservation Medicine Research Group, Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Matthijs Hollanders
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Thais Sasso
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Mariel Familiar López
- School of Environment and Sciences, Griffith University, Gold Coast, Qld., 4215, Australia
| | - David A Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Auston M Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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13
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Zumbado‐Ulate H, García‐Rodríguez A, Searle CL. Species distribution models predict the geographic expansion of an enzootic amphibian pathogen. Biotropica 2020. [DOI: 10.1111/btp.12863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Adrián García‐Rodríguez
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de MéxicoUNAM Ciudad de México México
- Museo de Zoología Escuela de Biología Universidad de Costa Rica San José Costa Rica
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14
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Beukema W, Pasmans F, Van Praet S, Ferri-Yáñez F, Kelly M, Laking AE, Erens J, Speybroeck J, Verheyen K, Lens L, Martel A. Microclimate limits thermal behaviour favourable to disease control in a nocturnal amphibian. Ecol Lett 2020; 24:27-37. [PMID: 33022129 DOI: 10.1111/ele.13616] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/15/2020] [Accepted: 09/07/2020] [Indexed: 11/28/2022]
Abstract
While epizootics increasingly affect wildlife, it remains poorly understood how the environment shapes most host-pathogen systems. Here, we employ a three-step framework to study microclimate influence on ectotherm host thermal behaviour, focusing on amphibian chytridiomycosis in fire salamanders (Salamandra salamandra) infected with the fungal pathogen Batrachochytrium salamandrivorans (Bsal). Laboratory trials reveal that innate variation in thermal preference, rather than behavioural fever, can inhibit infection and facilitate salamander recovery under humidity-saturated conditions. Yet, a 3-year field study and a mesocosm experiment close to the invasive Bsal range show that microclimate constraints suppress host thermal behaviour favourable to disease control. A final mechanistic model, that estimates range-wide, year-round host body temperature relative to microclimate, suggests that these constraints are rule rather than exception. Our results demonstrate how innate host defences against epizootics may remain constrained in the wild, which predisposes to range-wide disease outbreaks and population declines.
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Affiliation(s)
- Wouter Beukema
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Frank Pasmans
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Sarah Van Praet
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Francisco Ferri-Yáñez
- Department of Community Ecology, Helmholtz Centre for Environmental Research (UFZ), Theodor-Lieser-Strasse 4, Halle, 06120, Germany
| | - Moira Kelly
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Alexandra E Laking
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Jesse Erens
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Jeroen Speybroeck
- Research Institute for Nature and Forest - INBO, Havenlaan 88 bus 73, Brussels, 1000, Belgium
| | - Kris Verheyen
- Forest & Nature Lab, Department of Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, Gontrode, 9090, Belgium
| | - Luc Lens
- Terrestrial Ecology Unit, Ghent University, K. L, Ledeganckstraat 35, Ghent, 9000, Belgium
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
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15
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A highly invasive chimeric ranavirus can decimate tadpole populations rapidly through multiple transmission pathways. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.108777] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Endemic Infection of Batrachochytrium dendrobatidis in Costa Rica: Implications for Amphibian Conservation at Regional and Species Level. DIVERSITY 2019. [DOI: 10.3390/d11080129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Batrachochytrium dendrobatidis (Bd) has been associated with the severe declines and extinctions of amphibians in Costa Rica that primarily occurred during the 1980s and 1990s. However, the current impact of Bd infection on amphibian species in Costa Rica is unknown. We aimed to update the list of amphibian species in Costa Rica and evaluate the prevalence and infection intensity of Bd infection across the country to aid in the development of effective conservation strategies for amphibians. We reviewed taxonomic lists and included new species descriptions and records for a total of 215 amphibian species in Costa Rica. We also sampled for Bd at nine localities from 2015–2018 and combined these data with additional Bd occurrence data from multiple studies conducted in amphibian communities across Costa Rica from 2005–2018. With this combined dataset, we found that Bd was common (overall infection rate of 23%) across regions and elevations, but infection intensity was below theoretical thresholds associated with mortality. Bd was also more prevalent in Caribbean lowlands and in terrestrial amphibians with an aquatic larval stage; meanwhile, infection load was the highest in direct-developing species (forest and stream-dwellers). Our findings can be used to prioritize regions and taxonomic groups for conservation strategies.
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17
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Briscoe NJ, Elith J, Salguero-Gómez R, Lahoz-Monfort JJ, Camac JS, Giljohann KM, Holden MH, Hradsky BA, Kearney MR, McMahon SM, Phillips BL, Regan TJ, Rhodes JR, Vesk PA, Wintle BA, Yen JDL, Guillera-Arroita G. Forecasting species range dynamics with process-explicit models: matching methods to applications. Ecol Lett 2019; 22:1940-1956. [PMID: 31359571 DOI: 10.1111/ele.13348] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/14/2019] [Accepted: 06/20/2019] [Indexed: 01/14/2023]
Abstract
Knowing where species occur is fundamental to many ecological and environmental applications. Species distribution models (SDMs) are typically based on correlations between species occurrence data and environmental predictors, with ecological processes captured only implicitly. However, there is a growing interest in approaches that explicitly model processes such as physiology, dispersal, demography and biotic interactions. These models are believed to offer more robust predictions, particularly when extrapolating to novel conditions. Many process-explicit approaches are now available, but it is not clear how we can best draw on this expanded modelling toolbox to address ecological problems and inform management decisions. Here, we review a range of process-explicit models to determine their strengths and limitations, as well as their current use. Focusing on four common applications of SDMs - regulatory planning, extinction risk, climate refugia and invasive species - we then explore which models best meet management needs. We identify barriers to more widespread and effective use of process-explicit models and outline how these might be overcome. As well as technical and data challenges, there is a pressing need for more thorough evaluation of model predictions to guide investment in method development and ensure the promise of these new approaches is fully realised.
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Affiliation(s)
- Natalie J Briscoe
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Jane Elith
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Roberto Salguero-Gómez
- Department of Zoology, University of Oxford, Oxford, UK.,School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia.,Max Planck Institute for Demographic Research, Rostock, Germany
| | | | - James S Camac
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | | | - Matthew H Holden
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Bronwyn A Hradsky
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Michael R Kearney
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Sean M McMahon
- Forest Global Earth Observatory, Smithsonian Environmental Research Center, Edgewater, MD, USA
| | - Ben L Phillips
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Tracey J Regan
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia.,The Arthur Rylah Institute for Environmental Research, Department of Environment, Land, Water and Planning, Heidelberg, Vic., Australia
| | - Jonathan R Rhodes
- School of Earth and Environmental Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Peter A Vesk
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Brendan A Wintle
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
| | - Jian D L Yen
- School of BioSciences, University of Melbourne, Melbourne, Vic., Australia
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18
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Thorpe CJ, Lewis TR, Fisher MC, Wierzbicki CJ, Kulkarni S, Pryce D, Davies L, Watve A, Knight ME. Climate structuring of Batrachochytrium dendrobatidis infection in the threatened amphibians of the northern Western Ghats, India. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180211. [PMID: 30110422 PMCID: PMC6030269 DOI: 10.1098/rsos.180211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/04/2018] [Indexed: 05/08/2023]
Abstract
Batrachochytrium dendrobatidis (Bd) is a pathogen killing amphibians worldwide. Its impact across much of Asia is poorly characterized. This study systematically surveyed amphibians for Bd across rocky plateaus in the northern section of the Western Ghats biodiversity hotspot, India, including the first surveys of the plateaus in the coastal region. These ecosystems offer an epidemiological model system since they are characterized by differing levels of connectivity, edaphic and climatic conditions, and anthropogenic stressors. One hundred and eighteen individuals of 21 species of Anura and Apoda on 13 plateaus ranging from 67 to 1179 m above sea level and 15.89 to 17.92° North latitude were sampled. Using qPCR protocols, 79% of species and 27% of individuals tested were positive for Bd. This is the first record of Bd in caecilians in India, the Critically Endangered Xanthophryne tigerina and Endangered Fejervarya cf. sahyadris. Mean site prevalence was 28.15%. Prevalence below the escarpment was 31.2% and 25.4% above. The intensity of infection (GE) showed the reverse pattern. Infection may be related to elevational temperature changes, thermal exclusion, inter-site connectivity and anthropogenic disturbance. Coastal plateaus may be thermal refuges from Bd. Infected amphibians represented a wide range of ecological traits posing interesting questions about transmission routes.
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Affiliation(s)
- Christopher J. Thorpe
- Ecology, Behaviour and Evolution Research Group, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK
| | - Todd R. Lewis
- Westfield, 4 Worgret Road, Wareham, Dorset BH20 4PJ, UK
| | - Matthew C. Fisher
- Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK
| | - Claudia J. Wierzbicki
- Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK
| | - Siddharth Kulkarni
- Department of Biological Sciences, George Washington University, 2121 I St NW, Washington, DC 20052, USA
| | - David Pryce
- Ecology, Behaviour and Evolution Research Group, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK
| | - Lewis Davies
- Ecology, Behaviour and Evolution Research Group, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK
| | - Aparna Watve
- Tata Institute of Social Sciences, Apsinga Road, PO Box No. 09, Tuljapur 413 601, District-Osmanabad, Maharashtra, India
| | - Mairi E. Knight
- Ecology, Behaviour and Evolution Research Group, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK
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