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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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2
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Salla RF, Costa MJ, Abdalla FC, Oliveira CR, Tsukada E, Boeing GANS, Prado J, Carvalho T, Ribeiro LP, Rebouças R, Toledo LF. Estrogen contamination increases vulnerability of amphibians to the deadly chytrid fungus. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170337. [PMID: 38301782 DOI: 10.1016/j.scitotenv.2024.170337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/31/2023] [Accepted: 01/19/2024] [Indexed: 02/03/2024]
Abstract
Aquatic contaminants and infectious diseases are among the major drivers of global amphibian declines. However, the interaction of these factors is poorly explored and could better explain the amphibian crisis. We exposed males and females of the Brazilian Cururu Toad, Rhinella icterica, to an environmentally relevant concentration of the estrogen 17-alpha-ethinylestradiol (an emerging contaminant) and to the chytrid infection (Batrachochytrium dendrobatidis), in their combined and isolated forms, and the ecotoxicity was determined by multiple biomarkers: cutaneous, hematological, cardiac, hepatic, and gonadal analysis. Our results showed that Cururu toads had many physiological alterations in response to the chytrid infection, including the appearance of cutaneous Langerhans's cells, increased blood leukocytes, increased heart contraction force and tachycardia, increased hepatic melanomacrophage cells, which in turn led to gonadal atrophy. The estrogen, in turn, increased the susceptibility of the toads to the chytrid infection (higher Bd loads) and maximized the deleterious effects of the pathogen: reducing leukocytes, decreasing the contraction force, and causing greater tachycardia, increasing hepatic melanomacrophage cells, and leading to greater gonadal atrophy, which were more extreme in females. The exposure to estrogen also revealed important toxicodynamic pathways of this toxicant, as shown by the immunosuppression of exposed animals, and the induction of the first stages of feminization in males, which corroborates that the synthetic estrogen acts as an endocrine disruptor. Such an intricate relationship is unprecedented and reinforces the importance of studying the serious consequences that multiple environmental stressors can cause to aquatic populations.
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Affiliation(s)
- Raquel F Salla
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil; Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil.
| | - Monica Jones Costa
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil; Laboratório de Fisiologia da Conservação (LaFisC), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Fabio Camargo Abdalla
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil; Laboratório de Biologia Estrutural e Funcional (LaBEF), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Cristiane R Oliveira
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Elisabete Tsukada
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Guilherme Andrade Neto Schmitz Boeing
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil; Laboratório de Biologia Estrutural e Funcional (LaBEF), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Joelma Prado
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Tamilie Carvalho
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil; Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Luisa P Ribeiro
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Raoni Rebouças
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
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Martínez-Ruiz EB, Agha R, Spahr S, Wolinska J. Widely used herbicide metolachlor can promote harmful bloom formation by stimulating cyanobacterial growth and driving detrimental effects on their chytrid parasites. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123437. [PMID: 38272168 DOI: 10.1016/j.envpol.2024.123437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
Metolachlor (MET) is a widely used herbicide that can adversely affect phytoplanktonic non-target organisms, such as cyanobacteria. Chytrids are zoosporic fungi ubiquitous in aquatic environments that parasitize cyanobacteria and can keep their proliferation in check. However, the influence of organic pollutants on the interaction between species, including parasitism, and the associated ecological processes remain poorly understood. Using the host-parasite system consisting of the toxigenic cyanobacterium Planktothrix agardhii and its chytrid parasite Rhizophydium megarrhizum, we investigated the effects of environmentally relevant concentrations of MET on host-parasite interactions under i) continuous exposure of chytrids and cyanobacteria, and ii) pre-exposure of chytrids. During a continuous exposure, the infection prevalence and intensity were not affected, but chytrid reproductive structures were smaller at the highest tested MET concentration. In the parasite's absence, MET promoted cyanobacteria growth possibly due to a hormesis effect. In the pre-exposure assay, MET caused multi- and transgenerational detrimental effects on parasite fitness. Chytrids pre-exposed to MET showed reduced infectivity, intensity, and prevalence of the infection, and their sporangia size was reduced. Thus, pre-exposure of the parasite to MET resulted in a delayed decline of the cyanobacterial cultures upon infection. After several parasite generations without MET exposure, the parasite recovered its initial fitness, indicating that detrimental effects are transient. This study demonstrates that widely used herbicides, such as MET, could favor cyanobacterial bloom formation both directly, by promoting cyanobacteria growth, and indirectly, by inhibiting their chytrid parasites, which are known to play a key role as top-down regulators of cyanobacteria. In addition, we evidence the relevance of addressing multi-organism systems, such as host-parasite interactions, in toxicity assays. This approach offers a more comprehensive understanding of the effects of pollutants on aquatic ecosystems.
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Affiliation(s)
- Erika Berenice Martínez-Ruiz
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
| | - Ramsy Agha
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Stephanie Spahr
- Department of Ecohydrology and Biogeochemistry, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Justyna Wolinska
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Germany
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4
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Norris DO. Thyroid and reproduction in amphibians and reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:869-877. [PMID: 37522483 DOI: 10.1002/jez.2737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 08/01/2023]
Abstract
The relationship between the thyroid gland and reproduction in amphibians and reptiles has been studied for more than 100 years. Most studies suggest a positive involvement of thyroid hormones with some aspects of reproduction, but some studies support a negative role for thyroid hormones at certain life stages. Comprehensive studies of gene activation/suppression by thyroid hormones and their absence at various levels of the hypothalamo-pituitary-gonadal axis coupled with observations of adrenocorticoid activity, reproductive performance, and metabolic involvement are needed to understand this complex relationship.
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Affiliation(s)
- David O Norris
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
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Paetow LJ, Cue RI, Pauli BD, Marcogliese DJ. Effects of Herbicides and the Chytrid Fungus Batrachochytrium dendrobatidis on the growth, development and survival of Larval American Toads (Anaxyrus americanus). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 259:115021. [PMID: 37216860 DOI: 10.1016/j.ecoenv.2023.115021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 05/08/2023] [Accepted: 05/14/2023] [Indexed: 05/24/2023]
Abstract
Pesticides and pathogens adversely affect amphibian health, but their interactive effects are not well known. We assessed independent and combined effects of two agricultural herbicides and the fungal pathogen Batrachochytrium dendrobatidis (Bd) on the growth, development and survival of larval American toads (Anaxyrus americanus). Wild-caught tadpoles were exposed to four concentrations of atrazine (0.18, 1.8, 18.0, 180 μg/L) or glyphosate (7, 70, 700, 7000 µg a.e./L), respectively contained in Aatrex® Liquid 480 (Syngenta) or Vision® Silviculture Herbicide (Monsanto) for 14 days, followed by two doses of Bd. At day 14, atrazine had not affected survival, but it non-monotonically affected growth. Exposure to the highest concentration of glyphosate caused 100% mortality within 4 days, while lower doses had an increasing monotonic effect on growth. At day 65, tadpole survival was unaffected by atrazine and the lower doses of glyphosate. Neither herbicide demonstrated an interaction effect with Bd on survival, but exposure to Bd increased survival among both herbicide-exposed and herbicide-control tadpoles. At day 60, tadpoles exposed to the highest concentration of atrazine remained smaller than controls, indicating longer-term effects of atrazine on growth, but effects of glyphosate on growth disappeared. Growth was unaffected by any herbicide-fungal interaction but was positively affected by exposure to Bd following exposure to atrazine. Atrazine exhibited a slowing and non-monotonic effect on Gosner developmental stage, while exposure to Bd tended to speed up development and act antagonistically toward the observed effect of atrazine. Overall, atrazine, glyphosate and Bd all showed a potential to modulate larval toad growth and development.
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Affiliation(s)
- Linda J Paetow
- Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, Quebec H4B 1R6, Canada.
| | - Roger I Cue
- Department of Animal Science, McGill University, 21111 Lakeshore Rd., Ste. Anne-de-Bellevue, Quebec H9X 3V9, Canada
| | - Bruce D Pauli
- Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1A 0H3, Canada
| | - David J Marcogliese
- Aquatic Contaminants Research Division, Water Science and Technology Directorate, Science and Technology Branch, St. Lawrence Centre, Environment and Climate Change Canada, 105 McGill, 7th Floor, Montreal, Quebec H2Y 2E7, Canada
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6
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McQuigg JL, Kissner K, Boone MD. Exposure to Amphibian Chytrid Fungus Alters Terrestrial Growth and Feeding Rate in Metamorphic Anurans. J HERPETOL 2023. [DOI: 10.1670/21-048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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7
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Hocking S, Toop T, Jones D, Graham I, Eastwood D. Assessing the relative impacts and economic costs of Japanese knotweed management methods. Sci Rep 2023; 13:3872. [PMID: 36932085 PMCID: PMC10023688 DOI: 10.1038/s41598-023-30366-9] [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] [Received: 10/27/2022] [Accepted: 02/21/2023] [Indexed: 03/19/2023] Open
Abstract
Sustainable land management encompasses a range of activity that balance land use requirements with wider conservation and ecosystem impact considerations. Perennial invasive alien plants (IAPs), such as Japanese knotweed, cause severe ecological and socio-economic impacts, and methods to control their spread also come at a cost. Synthetic herbicides are generally viewed as less sustainable and more ecologically damaging than alternative approaches. Here we used a comparative Life Cycle Assessment to evaluate the sustainability of herbicide-based management approaches and physical alternatives, using a large-scale Japanese knotweed field study as a model IAP system. Glyphosate-based methods elicited the lowest environmental impacts and economic costs during production. Geomembrane covering and integrated physiochemical methods were the costliest and imposed the greatest impacts. We discuss the costs and benefits of chemical and physical approaches for the sustainable management of invaded land and question how sustainable environmental stewardship is defined for the control of IAPs.
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Affiliation(s)
- Sophie Hocking
- Department of Biosciences, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
| | - Trisha Toop
- Agri-EPI Centre, Poultry Lane, Edgmond, Newport, TF10 8JZ, England, UK
- Harper Adams University, Poultry Lane, Edgmond, Newport, TF10 8NB, England, UK
| | - Daniel Jones
- Department of Biosciences, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
- Advanced Invasives Ltd., Sophia House, 28 Cathedral Road, Cardiff, CF11 9LJ, UK
| | - Ian Graham
- Complete Weed Control Ltd., Unit 16, Hurworth Road, Newton Aycliffe, DL5 6UD, UK
| | - Daniel Eastwood
- Department of Biosciences, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
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8
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Delayed Effects of Nutrients in the Larval Environment on Cope's Gray Treefrogs (Hyla chrysoscelis) Exposed to Batrachochytrium dendrobatidis. J HERPETOL 2022. [DOI: 10.1670/21-058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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9
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Goessens T, De Baere S, Deknock A, De Troyer N, Van Leeuwenberg R, Martel A, Pasmans F, Goethals P, Lens L, Spanoghe P, Vanhaecke L, Croubels S. Agricultural contaminants in amphibian breeding ponds: Occurrence, risk and correlation with agricultural land use. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150661. [PMID: 34597541 DOI: 10.1016/j.scitotenv.2021.150661] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Anthropogenic pressure such as agricultural pollution globally affects amphibian populations. In this study, a total of 178 different compounds from five agrochemical groups (i.e. antimicrobial drugs residues (ADRs), coccidiostats and anthelmintics, heavy metals, mycotoxins and pesticides) were determined monthly, from March until June 2019 in 26 amphibian breeding ponds in Flanders, Belgium. Furthermore, a possible correlation between the number and concentration of selected contaminants that were found and the percentage of arable land within a 200 m radius was studied. Within each group, the highest detected concentrations were obtained for 4-epioxytetracycline (0.422 μg L-1), levamisole (0.550 μg L-1), zinc (333.1 μg L-1), 3-acetyldeoxynivalenol (0.013 μg L-1), and terbuthylazine (38.7 μg L-1), respectively, with detection frequencies ranging from 1 (i.e. 3-acetyldeoxynivalenol) to 26 (i.e. zinc) out of 26 ponds. Based on reported acute and chronic ecotoxicological endpoints, detected concentrations of bifenthrin, cadmium, copper, cypermethrin, hexachlorobenzene, mercury, terbuthylazine, and zinc pose a substantial ecological risk to aquatic invertebrates such as Daphnia magna and Ceriodaphnia dubia, which both play a role in the food web and potentially in amphibian disease dynamics. Additionally, the detected concentrations of copper were high enough to exert chronic toxicity in the gray treefrog (Hyla versicolor). The number of detected compounds per pond ranged between 0 and 5 (ADRs), 0 - 2 (coccidiostats and anthelmintics), 1 - 7 (heavy metals), 0 - 4 (mycotoxins), and 0 - 12 (pesticides) across the four months. Furthermore, no significant correlation was demonstrated between the number of detected compounds per pond, as well as the detected concentrations of 4-epioxytetracycline, levamisole, copper, zinc, enniatin B and terbuthylazine, and the percentage of arable land within a 200 m radius. For heavy metals and pesticides, the number of compounds per pond varied significantly between months. Conclusively, amphibian breeding ponds in Flanders were frequently contaminated with agrochemicals, yielding concentrations up to the high μg per liter level, regardless of the percentage surrounding arable land, however showing temporal variation for heavy metals and pesticides. This research also identifies potential hazardous substances which may be added to the European watch list (CD 2018/408/EC) in the future.
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Affiliation(s)
- T Goessens
- Ghent University, Department of Pharmacology, Toxicology and Biochemistry, Laboratory of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Merelbeke, Belgium.
| | - S De Baere
- Ghent University, Department of Pharmacology, Toxicology and Biochemistry, Laboratory of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Merelbeke, Belgium
| | - A Deknock
- Ghent University, Department of Biology, Animal Sciences and Aquatic Ecology, Aquatic Ecology Unit, Faculty of Bioscience Engineering, Ghent, Belgium
| | - N De Troyer
- Ghent University, Department of Biology, Animal Sciences and Aquatic Ecology, Aquatic Ecology Unit, Faculty of Bioscience Engineering, Ghent, Belgium
| | - R Van Leeuwenberg
- Ghent University, Department of Pathology, Bacteriology and Avian Diseases, Laboratory of Bacteriology and Mycology, Wildlife Health Ghent, Faculty of Veterinary Medicine, Merelbeke, Belgium
| | - A Martel
- Ghent University, Department of Pathology, Bacteriology and Avian Diseases, Laboratory of Bacteriology and Mycology, Wildlife Health Ghent, Faculty of Veterinary Medicine, Merelbeke, Belgium
| | - F Pasmans
- Ghent University, Department of Pathology, Bacteriology and Avian Diseases, Laboratory of Bacteriology and Mycology, Wildlife Health Ghent, Faculty of Veterinary Medicine, Merelbeke, Belgium
| | - P Goethals
- Ghent University, Department of Biology, Animal Sciences and Aquatic Ecology, Aquatic Ecology Unit, Faculty of Bioscience Engineering, Ghent, Belgium
| | - L Lens
- Ghent University, Department of Biology, Terrestrial Ecology Unit, Faculty of Sciences, Ghent, Belgium
| | - P Spanoghe
- Ghent University, Department of Plants and Crops, Laboratory of Crop Protection Chemistry, Faculty of Bioscience Engineering, Ghent, Belgium
| | - L Vanhaecke
- Ghent University, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, Faculty of Veterinary Medicine, Merelbeke, Belgium; Queen's University, School of Biological Sciences, Institute for Global Food Security, Belfast, Ireland
| | - S Croubels
- Ghent University, Department of Pharmacology, Toxicology and Biochemistry, Laboratory of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Merelbeke, Belgium
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Carrasco GH, de Souza MB, de Souza Santos LR. Effect of multiple stressors and population decline of frogs. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:59519-59527. [PMID: 34505245 DOI: 10.1007/s11356-021-16247-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
The ongoing decline in anuran populations is linked primarily to the effects of stressor agents such as pathogens, pesticides, alterations of natural landscapes, and the introduction of exotic species. Most studies that have evaluated the effects of these stressors have focused on a single component, which is the opposite of the reality of most natural environments, where anuran populations tend to suffer the influence of multiple agents simultaneously. Studies of the effects of the interaction between these components are extremely important, given that one agent may potentialize (synergistic effect) or weaken another (antagonistic effect) or, in some cases, have a neutral effect. The present study is based on the scientometric analysis of three bibliographic databases (ISI Web of Science, Scopus, and PubMed), which identified 1376 papers that reported on the global decline of anuran populations, although only 172 of these studies focused on the interactive effects of environmental stressors. Synergistic effects were the most frequent type of interaction, followed by antagonistic effects, and a small number of studies that found no clear interaction between the stressors. Pathogens and pesticides were the classes of stressor studied most frequently, while climate-pathogen and pathogen-pesticide interactions were the combinations that featured in the largest number of studies. Overall, we would recommend a more systematic focus on the dynamics of the interactions among the stressors that impact anuran populations, in particular for the elaboration of conservation programs, given that these agents tend to have complex combined effects.
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Affiliation(s)
- Guilherme Henrique Carrasco
- Laboratório de Ecotoxicologia e Sistemática Animal - Instituto Federal Goiano - IF Goiano, Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, GO, 75.901-970, Brazil.
| | - Marcelino Benvindo de Souza
- Laboratório de Mutagênese, Instituto de Ciências Biológicas, ICB I - Universidade Federal de Goiás, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Lia Raquel de Souza Santos
- Laboratório de Ecotoxicologia e Sistemática Animal - Instituto Federal Goiano - IF Goiano, Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, GO, 75.901-970, Brazil.
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11
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Smalling KL, Breitmeyer SE, Bunnell JF, Laidig KJ, Burritt PM, Sobel MC, Cohl JA, Hladik ML, Romanok KM, Bradley PM. Assessing the ecological functionality and integrity of natural ponds, excavated ponds and stormwater basins for conserving amphibian diversity. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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12
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Effects of Temperature and Glyphosate on Fatty Acid Composition, Antioxidant Capacity, and Lipid Peroxidation in the Gastropod Lymneae sp. WATER 2021. [DOI: 10.3390/w13081039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Little is known about the potential effects of glyphosate on freshwater gastropods and possible interactions between glyphosate and other stressors. A two-way factorial experiment was conducted to investigate the effects of temperature (20 °C/25 °C) and glyphosate (0 µg/L/200 µg/L) on Lymnaea sp. After 21 days, antioxidant capacity (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST)), malondialdehyde content (MDA), and fatty acid (FA) composition of Lymnaea sp. tissue were measured. Temperature had an effect on SOD activity and GPx activity. In contrast, an increase in GST activity was observed in glyphosate-exposed snails, highlighting the role of GST in the glyphosate detoxification process. Differences in temperature and glyphosate did not affect lipid peroxidation (MDA); however, we observed a trend suggesting the presence of higher MDA content in glyphosate-exposed snails at 20 °C. The FA groups were generally not strongly affected by the treatments, except for omega−9 (n-9) that was markedly lower at the higher temperature. Changes were also observed in individual FA as a response to glyphosate and/or temperature. For example, a significant decrease in 18:1n9 was observed at 25 °C. Our results showed that antioxidant capacity and FA profiles were mainly affected by temperature, while glyphosate seemed to have a lesser impact.
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Cusaac JPW, Carter ED, Woodhams DC, Robert J, Spatz JA, Howard JL, Lillard C, Graham AW, Hill RD, Reinsch S, McGinnity D, Reeves B, Bemis D, Wilkes RP, Sutton WB, Waltzek TB, Hardman RH, Miller DL, Gray MJ. Emerging Pathogens and a Current-Use Pesticide: Potential Impacts on Eastern Hellbenders. JOURNAL OF AQUATIC ANIMAL HEALTH 2021; 33:24-32. [PMID: 33590581 DOI: 10.1002/aah.10117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 08/15/2020] [Accepted: 10/05/2020] [Indexed: 06/12/2023]
Abstract
Populations of the eastern hellbender Cryptobranchus alleganiensis alleganiensis have been declining for decades, and emerging pathogens and pesticides are hypothesized to be contributing factors. However, few empirical studies have attempted to test the potential effects of these factors on hellbenders. We simultaneously exposed subadult hellbenders to environmentally relevant concentrations of either Batrachochytrium dendrobatidis (Bd) or a frog virus 3-like ranavirus (RV), a combination of the pathogens, or each pathogen following exposure to a glyphosate herbicide (Roundup). Additionally, we measured the ability of the skin mucosome to inactivate Bd and RV in growth assays. We found that mucosome significantly inactivated RV by an average of 40% but had no negative effects on Bd growth. All treatments that included RV exposure experienced reduced survival compared to controls, and the combination of RV and herbicide resulted in 100% mortality. Histopathology verified RV as the cause of mortality in all RV-exposed treatments. No animals were infected with Bd or died in the Bd-only treatment. Our results suggest that RV exposure may be a significant threat to the survival of subadult hellbenders and that Roundup exposure may potentially exacerbate this threat.
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Affiliation(s)
- J Patrick W Cusaac
- Center for Wildlife Health, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Edward Davis Carter
- Center for Wildlife Health, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, 02125, USA
| | - Jacques Robert
- University of Rochester Medical Center, Rochester, New York, 14642, USA
| | - Jennifer A Spatz
- Center for Wildlife Health, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Jennifer L Howard
- Center for Wildlife Health and College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Carson Lillard
- Center for Wildlife Health, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Allison W Graham
- Center for Wildlife Health and College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Rachel D Hill
- Center for Wildlife Health, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | | | | | - Bill Reeves
- Tennessee Wildlife Resources Agency, Nashville, Tennessee, 37220, USA
| | - David Bemis
- College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Rebecca P Wilkes
- Department of Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, 47907, USA
| | - William B Sutton
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, Tennessee, 37209, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, Florida, 32611, USA
| | - Rebecca H Hardman
- Center for Wildlife Health and College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Debra L Miller
- Center for Wildlife Health and College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee, Knoxville, Tennessee, 37996, USA
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Preuss JF, Greenspan SE, Rossi EM, Lucas Gonsales EM, Neely WJ, Valiati VH, Woodhams DC, Becker CG, Tozetti AM. Widespread Pig Farming Practice Linked to Shifts in Skin Microbiomes and Disease in Pond-Breeding Amphibians. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11301-11312. [PMID: 32845628 DOI: 10.1021/acs.est.0c03219] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Farming practices may reshape the structure of watersheds, water quality, and the health of aquatic organisms. Nutrient enrichment from agricultural pollution increases disease pressure in many host-pathogen systems, but the mechanisms underlying this pattern are not always resolved. For example, nutrient enrichment should strongly influence pools of aquatic environmental bacteria, which has the potential to alter microbiome composition of aquatic animals and their vulnerability to disease. However, shifts in the host microbiome have received little attention as a link between nutrient enrichment and diseases of aquatic organisms. We examined nutrient enrichment through the widespread practice of integrated pig-fish farming and its effects on microbiome composition of Brazilian amphibians and prevalence of the globally distributed amphibian skin pathogen Batrachochytrium dendrobatidis (Bd). This farming system drove surges in fecal coliform bacteria, disturbing amphibian skin bacterial communities such that hosts recruited higher proportions of Bd-facilitative bacteria and carried higher Bd prevalence. Our results highlight previously overlooked connections between global trends in land use change, microbiome dysbiosis, and wildlife disease. These interactions may be particularly important for disease management in the tropics, a region with both high biodiversity and continually intensifying anthropogenic pressures on aquatic wildlife habitats.
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Affiliation(s)
- Jackson F Preuss
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
- Departamento de Ciências da Vida, Universidade do Oeste de Santa Catarina, São Miguel do Oeste, SC 89900-000, Brazil
| | - Sasha E Greenspan
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Eliandra M Rossi
- Departamento de Ciências da Vida, Universidade do Oeste de Santa Catarina, São Miguel do Oeste, SC 89900-000, Brazil
| | - Elaine M Lucas Gonsales
- Departamento de Zootecnia e Ciências Biológicas, Universidade Federal de Santa Maria, RS 98300-000, Brazil
| | - Wesley J Neely
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Victor Hugo Valiati
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
| | - Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - C Guilherme Becker
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Alexandro M Tozetti
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
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15
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Bienentreu JF, Lesbarrères D. Amphibian Disease Ecology: Are We Just Scratching the Surface? HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.153] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - David Lesbarrères
- Department of Biology, Laurentian University, Sudbury, ON P3E 2C6, Canada
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16
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Rumschlag SL, Boone MD. High juvenile mortality in amphibians during overwintering related to fungal pathogen exposure. DISEASES OF AQUATIC ORGANISMS 2018; 131:13-28. [PMID: 30324911 DOI: 10.3354/dao03277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The result of pathogen exposures may depend upon trade-offs in energetic demands for immune responses against host growth and survival. Environmental conditions may influence these trade-offs by affecting host size, or trade-offs may change across seasons, altering impacts of pathogens. We exposed northern leopard frog Lithobates pipiens tadpoles to different larval environments (low leaf litter, high density of conspecifics, atrazine, caged fish, or controls) that influenced size at metamorphosis. Subsequently, we exposed metamorphs to Batrachochytrium dendrobatidis (Bd), a fungal pathogen, just after metamorphosis and/or prior to overwintering 12 wk later. Bd exposure dramatically reduced survival during overwintering, with the strongest effects when hosts were exposed at both time points. Larval environments resulted in differences in host size. Those exposed to caged fish were 2.5 times larger than the smallest (those exposed to high density of conspecifics), but larval environment did not influence Bd effects on growth and survival. The largest frogs exposed to caged fish had greater survival through overwintering, but in the absence of Bd. We built stage-structured models to evaluate if overwinter mortality from Bd is capable of having effects on host populations. Our models suggest that Bd exposure after metamorphosis or before overwintering can reduce population growth rates. Our study demonstrates that hosts suffer little effects of Bd exposures following metamorphosis and that small body size did not hamper growth and survival. Instead, we provide evidence that winter mortality from Bd exposure is capable of reducing population sizes, providing a plausible mechanism for amphibian declines in temperate regions.
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17
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Rohr JR, Brown J, Battaglin WA, McMahon TA, Relyea RA. A pesticide paradox: fungicides indirectly increase fungal infections. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:2290-2302. [PMID: 28763165 PMCID: PMC5711531 DOI: 10.1002/eap.1607] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 04/21/2017] [Accepted: 07/11/2017] [Indexed: 05/17/2023]
Abstract
There are many examples where the use of chemicals have had profound unintended consequences, such as fertilizers reducing crop yields (paradox of enrichment) and insecticides increasing insect pests (by reducing natural biocontrol). Recently, the application of agrochemicals, such as agricultural disinfectants and fungicides, has been explored as an approach to curb the pathogenic fungus, Batrachochytrium dendrobatidis (Bd), which is associated with worldwide amphibian declines. However, the long-term, net effects of early-life exposure to these chemicals on amphibian disease risk have not been thoroughly investigated. Using a combination of laboratory experiments and analysis of data from the literature, we explored the effects of fungicide exposure on Bd infections in two frog species. Extremely low concentrations of the fungicides azoxystrobin, chlorothalonil, and mancozeb were directly toxic to Bd in culture. However, estimated environmental concentrations of the fungicides did not reduce Bd on Cuban tree frog (Osteopilus septentrionalis) tadpoles exposed simultaneously to any of these fungicides and Bd, and fungicide exposure actually increased Bd-induced mortality. Additionally, exposure to any of these fungicides as tadpoles resulted in higher Bd abundance and greater Bd-induced mortality when challenged with Bd post-metamorphosis, an average of 71 d after their last fungicide exposure. Analysis of data from the literature revealed that previous exposure to the fungicide itraconazole, which is commonly used to clear Bd infections, made the critically endangered booroolong frog (Litoria booroolongensis) more susceptible to Bd. Finally, a field survey revealed that Bd prevalence was positively associated with concentrations of fungicides in ponds. Although fungicides show promise for controlling Bd, these results suggest that, if fungicides do not completely eliminate Bd or if Bd recolonizes, exposure to fungicides has the potential to do more harm than good. To ensure that fungicide applications have the intended consequence of curbing amphibian declines, researchers must identify which fungicides do not compromise the pathogen resistance mechanisms of amphibians.
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Affiliation(s)
- Jason R. Rohr
- University of South Florida, Department of Integrative Biology, Tampa, FL 33620, USA
| | - Jenise Brown
- University of South Florida, Department of Integrative Biology, Tampa, FL 33620, USA
- SWCA Environmental Consultants, Pittsburgh, PA, 15017, USA
| | | | | | - Rick A. Relyea
- Department of Biological Sciences, Rensselaer Polytechnic Inst., Troy, NY 12180, USA
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18
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Xu Y, Li AJ, Li K, Qin J, Li H. Effects of glyphosate-based herbicides on survival, development and growth of invasive snail (Pomacea canaliculata). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 193:136-143. [PMID: 29078071 DOI: 10.1016/j.aquatox.2017.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/14/2017] [Accepted: 10/16/2017] [Indexed: 06/07/2023]
Abstract
This study tests the hypotheses that whether environmental relevance of glyphosate would help control spread of the invasive snail Pomacea canaliculata, or benefit its population growth worldwide. Our results showed that glyphosate induced acute toxicity to the snail only at high concentrations (96h LC50 at 175mg/L) unlikely to occur in the environment. Long-term exposures to glyphosate at sublethal levels (20 and 120mg/L) caused inhibition of food intake, limitation of growth performance and alterations in metabolic profiles of the snail. It is worth noting that glyphosate at 2mg/L benefited growth performance in P. canaliculata. Chronic exposures of glyphosate significantly enhanced overall metabolic rate and altered catabolism from protein to carbohydrate/lipid mode. Cellular responses in enzyme activities showed that the exposed snails could increase tolerance by their defense system against glyphosate-induced oxidative stress, and adjustment of metabolism to mitigate energy crisis. Our study displayed that sublethal concentrations of glyphosate might be helpful in control of the invasive species by food intake, growth performance and metabolic interruption; whether environmental relevance of glyphosate (≤2mg/L) benefits population growth of P. canaliculata is still inconclusive, which requires further field study.
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Affiliation(s)
- Yanggui Xu
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture/Key Laboratory of Agroecology and Rural Environment of Guangzhou Regular Higher Education Institutions, Guangzhou, 510642, China
| | - Adela Jing Li
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture/Key Laboratory of Agroecology and Rural Environment of Guangzhou Regular Higher Education Institutions, Guangzhou, 510642, China.
| | - Kaibin Li
- Key Laboratory of Tropical and Subtropical Fish Breeding & Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Junhao Qin
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture/Key Laboratory of Agroecology and Rural Environment of Guangzhou Regular Higher Education Institutions, Guangzhou, 510642, China
| | - Huashou Li
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture/Key Laboratory of Agroecology and Rural Environment of Guangzhou Regular Higher Education Institutions, Guangzhou, 510642, China.
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19
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Burrow AK, Rumschlag SL, Boone MD. Host size influences the effects of four isolates of an amphibian chytrid fungus. Ecol Evol 2017; 7:9196-9202. [PMID: 29187961 PMCID: PMC5696404 DOI: 10.1002/ece3.3255] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 06/14/2017] [Accepted: 06/28/2017] [Indexed: 11/11/2022] Open
Abstract
Understanding factors that influence host–pathogen interactions is key to predicting outbreaks in natural systems experiencing environmental change. Many amphibian population declines have been attributed to an amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd). While this fungus is widespread, not all Bd‐positive populations have been associated with declines, which could be attributed to differences in pathogen virulence or host susceptibility. In a laboratory experiment, we examined the effects of Bd isolate origin, two from areas with Bd‐associated amphibian population declines (El Copé, Panama, and California, USA) and two from areas without Bd‐related population declines (Ohio and Maine, USA), on the terrestrial growth and survival of American toad (Anaxyrus americanus) metamorphs reared in larval environments with low or high intraspecific density. We predicted that (1) Bd isolates from areas experiencing declines would have greater negative effects than Bd isolates from areas without declines, and (2) across all isolates, growth and survival of smaller toads from high‐density larval conditions would be reduced by Bd exposure compared to larger toads from low‐density larval conditions. Our results showed that terrestrial survival was reduced for smaller toads exposed to Bd with variation in the response to different isolates, suggesting that smaller size increased susceptibility to Bd. Toads exposed to Bd gained less mass, which varied by isolate. Bd isolates from areas with population declines, however, did not have more negative effects than isolates from areas without recorded declines. Most strikingly, our study supports that host condition, measured by size, can be indicative of the negative effects of Bd exposure. Further, Bd isolates’ impact may vary in ways not predictable from place of origin or occurrence of disease‐related population declines. This research suggests that amphibian populations outside of areas experiencing Bd‐associated declines could be impacted by this pathogen and that the size of individuals could influence the magnitude of Bd's impact.
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20
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Rodeo™ Herbicide Negatively Affects Blanchard's Cricket Frogs (Acris blanchardi) Survival and Alters the Skin-Associated Bacterial Community. J HERPETOL 2017. [DOI: 10.1670/16-092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Bókony V, Mikó Z, Móricz ÁM, Krüzselyi D, Hettyey A. Chronic exposure to a glyphosate-based herbicide makes toad larvae more toxic. Proc Biol Sci 2017; 284:20170493. [PMID: 28679726 PMCID: PMC5524492 DOI: 10.1098/rspb.2017.0493] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/01/2017] [Indexed: 01/18/2023] Open
Abstract
Chemical pollutants can exert various sublethal effects on wildlife, leading to complex fitness consequences. Many animals use defensive chemicals as protection from predators and diseases, yet the effects of chemical contaminants on this important fitness component are poorly known. Understanding such effects is especially relevant for amphibians, the globally most threatened group of vertebrates, because they are particularly vulnerable to chemical pollution. We conducted two experiments to investigate how exposure to glyphosate-based herbicides, the most widespread agrochemicals worldwide, affects the production of bufadienolides, the main compounds of chemical defence in common toads (Bufo bufo). In both experiments, herbicide exposure increased the amount of bufadienolides in toad tadpoles. In the laboratory, individuals exposed to 4 mg a.e./L glyphosate throughout their larval development had higher bufadienolide content at metamorphosis than non-exposed tadpoles, whereas exposure for 9 days to the same concentration or to 2 mg a.e./L throughout larval development or for 9 days had no detectable effect. In outdoor mesocosms, tadpoles from 16 populations exhibited elevated bufadienolide content after three-weeks exposure to both concentrations of the herbicide. These results show that pesticide exposure can have unexpected effects on non-target organisms, with potential consequences for the conservation management of toxin-producing species and their predators.
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Affiliation(s)
- Veronika Bókony
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
| | - Zsanett Mikó
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
| | - Ágnes M Móricz
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
| | - Dániel Krüzselyi
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
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22
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Mikó Z, Ujszegi J, Hettyey A. Age-dependent changes in sensitivity to a pesticide in tadpoles of the common toad (Bufo bufo). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 187:48-54. [PMID: 28365461 DOI: 10.1016/j.aquatox.2017.03.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/17/2017] [Accepted: 03/19/2017] [Indexed: 06/07/2023]
Abstract
The worldwide en masse application of pesticides and the frequently reported malign effects on several non-target organisms underpin the importance of ecotoxicological research on these anthropogenic pollutants. Previous studies showed that sensitivity to herbicides can vary widely depending on additional stress factors, on the species and even on the population investigated. However, there is little information about how sensitivity changes during ontogeny, and how the duration of exposure is linked to the magnitude of malign effects, even though this knowledge would be important for the interpretation of toxicity test results and for formulating recommendations regarding the timing of pesticide application. We exposed tadpoles of the common toad (Bufo bufo) to three concentrations (0, 2 and 4mg a.e./L) of a glyphosate-based herbicide during the 1st, 2nd, 3rd, 4th, or 5th period of larval development or during the entire experiment, and measured survival, time until metamorphosis and body mass at metamorphosis to estimate fitness-consequences. Younger tadpoles were more sensitive to the herbicide in all measured traits than older ones, and this age-dependence was especially pronounced at the high herbicide concentration. Furthermore, tadpoles exposed to the herbicide during the entire experiment developed slower than tadpoles exposed only early on, but we did not observe a similar effect either on body mass or survival. The observed age-dependence of sensitivity to herbicides draws attention to the fact that results of toxicity tests obtained for one age-class are not necessarily generalizable across ontogeny. Also, the age of test animals has to be considered when planning ecotoxicological studies and interpreting their results. Finally, taking into account the temporal breeding habits of local amphibians when planning pesticide application would be highly favourable: if tadpoles would not get exposed to the herbicide during their most sensitive early development, they would sustain less anthropogenic damage from our efforts of controlling weeds.
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Affiliation(s)
- Zsanett Mikó
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary.
| | - János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary; Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest 1117, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
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23
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Robinson SA, Richardson SD, Dalton RL, Maisonneuve F, Trudeau VL, Pauli BD, Lee-Jenkins SSY. Sublethal effects on wood frogs chronically exposed to environmentally relevant concentrations of two neonicotinoid insecticides. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:1101-1109. [PMID: 28248437 DOI: 10.1002/etc.3739] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/14/2016] [Accepted: 01/12/2017] [Indexed: 06/06/2023]
Abstract
Neonicotinoids are prophylactically used globally on a variety of crops, and there is concern for the potential impacts of neonicotinoids on aquatic ecosystems. The intensive use of pesticides on crops has been identified as a contributor to population declines of amphibians, but currently little is known regarding the sublethal effects of chronic neonicotinoid exposure on amphibians. The objective of the present study was to characterize the sublethal effect(s) of exposure to 3 environmentally relevant concentrations (1 μg/L, 10 μg/L, and 100 μg/L) of 2 neonicotinoids on larval wood frogs (Lithobates sylvaticus) using outdoor mesocosms. We exposed tadpoles to solutions of 2 commercial formulations containing imidacloprid and thiamethoxam, and assessed survival, growth, and development. Exposure to imidacloprid at 10 μg/L and 100 μg/L increased survival and delayed completion of metamorphosis compared with controls. Exposure to thiamethoxam did not influence amphibian responses. There was no significant effect of any treatment on body mass or size of the metamorphs. The results suggest that current usage of imidacloprid and thiamethoxam does not pose a threat to wood frogs. However, further assessment of both direct and indirect effects on subtle sublethal endpoints, and the influence of multiple interacting stressors at various life stages, is needed to fully understand the effects of neonicotinoids on amphibians. Environ Toxicol Chem 2017;36:1101-1109. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.
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Affiliation(s)
- Stacey A Robinson
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Sarah D Richardson
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Rebecca L Dalton
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - France Maisonneuve
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Bruce D Pauli
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Stacey S Y Lee-Jenkins
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario, Canada
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Becker C, Greenspan S, Tracy K, Dash J, Lambertini C, Jenkinson T, Leite D, Toledo L, Longcore J, James T, Zamudio K. Variation in phenotype and virulence among enzootic and panzootic amphibian chytrid lineages. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2016.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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25
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Romansic JM, Johnson JE, Wagner RS, Hill RH, Gaulke CA, Vredenburg VT, Blaustein AR. Complex interactive effects of water mold, herbicide, and the fungus Batrachochytrium dendrobatidis on Pacific treefrog Hyliola regilla hosts. DISEASES OF AQUATIC ORGANISMS 2017; 123:227-238. [PMID: 28322209 DOI: 10.3354/dao03094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Infectious diseases pose a serious threat to global biodiversity. However, their ecological impacts are not independent of environmental conditions. For example, the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which has contributed to population declines and extinctions in many amphibian species, interacts with several environmental factors to influence its hosts, but potential interactions with other pathogens and environmental contaminants are understudied. We examined the combined effects of Bd, a water mold (Achlya sp.), and the herbicide Roundup® Regular (hereafter, Roundup®) on larval Pacific treefrog Hyliola regilla hosts. We employed a 2 wk, fully factorial laboratory experiment with 3 ecologically realistic levels (0, 1, and 2 mg l-1 of active ingredient) of field-formulated Roundup®, 2 Achlya treatments (present and absent), and 2 Bd treatments (present and absent). Our results were consistent with sublethal interactive effects involving all 3 experimental factors. When Roundup® was absent, the proportion of Bd-exposed larvae infected with Bd was elevated in the presence of Achlya, consistent with Achlya acting as a synergistic cofactor that facilitated the establishment of Bd infection. However, this Achlya effect became nonsignificant at 1 mg l-1 of the active ingredient of Roundup® and disappeared at the highest Roundup® concentration. In addition, Roundup® decreased Bd loads among Bd-exposed larvae. Our study suggests complex interactive effects of a water mold and a contaminant on Bd infection in amphibian hosts. Achlya and Roundup® were both correlated with altered patterns of Bd infection, but in different ways, and Roundup® appeared to remove the influence of Achlya on Bd.
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Affiliation(s)
- John M Romansic
- Department of Integrative Biology, 3029 Cordley Hall, Oregon State University, Corvallis, Oregon 97331, USA
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26
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Bach NC, Natale GS, Somoza GM, Ronco AE. Effect on the growth and development and induction of abnormalities by a glyphosate commercial formulation and its active ingredient during two developmental stages of the South-American Creole frog, Leptodactylus latrans. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:23959-23971. [PMID: 27638798 DOI: 10.1007/s11356-016-7631-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 09/07/2016] [Indexed: 06/06/2023]
Abstract
We evaluated the acute lethal and sublethal effects of technical-grade glyphosate (GLY) and the GLY-based commercial formulation Roundup ULTRA MAX® (RU) on two Gosner stages (Gss) 25 and 36 of the South-American Creole frog, Leptodactylus latrans. Bioassays were performed following standardized methods within a wide range of concentrations (0.0007-9.62 mg of acid equivalents per liter-a.e./L-of RU and 3-300 mg/L of GLY). The endpoints evaluated were mortality, swimming activity, growth, development, and the presence of morphologic abnormalities, especially in the mouthparts. No lethal effects were observed on larvae exposed to GLY during either Gs-25 or Gs-36. The concentrations inducing 50 % lethality in RU-exposed larvae at different exposure times and Gss ranged from 3.26 to 9.61 mg a.e./L. Swimming activity was affected by only RU. Effects on growth and development and the induction of morphologic abnormalities-like oral abnormalities and edema-were observed after exposure to either GLY or RU. Gs-25 was the most sensitive stage to both forms of the herbicide. The commercial formulation was much more toxic than the active ingredient on all the endpoints assessed. Effects on growth, development, and the induction of morphologic abnormalities observed in the range of environmental concentrations reported for agroecosystems of Argentina constitute an alert to the potential detrimental effects of the herbicide that could be affecting the fitness and survival of anurans in agroecosystems.
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Affiliation(s)
- Nadia Carla Bach
- Centro de Investigaciones del Medio Ambiente (CIMA), Facultad de Ciencias Exactas and CONICET, Universidad Nacional de La Plata, Calle 47 y 115. La Plata, 1900, Buenos Aires, Argentina
| | - Guillermo Sebastián Natale
- Centro de Investigaciones del Medio Ambiente (CIMA), Facultad de Ciencias Exactas and CONICET, Universidad Nacional de La Plata, Calle 47 y 115. La Plata, 1900, Buenos Aires, Argentina
| | - Gustavo Manuel Somoza
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (CONICET-UNSAM), Av. Intendente Marino Km. 8.2 (B7130IWA), Chascomús, Buenos Aires, Argentina
| | - Alicia Estela Ronco
- Centro de Investigaciones del Medio Ambiente (CIMA), Facultad de Ciencias Exactas and CONICET, Universidad Nacional de La Plata, Calle 47 y 115. La Plata, 1900, Buenos Aires, Argentina.
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Battaglin WA, Smalling KL, Anderson C, Calhoun D, Chestnut T, Muths E. Potential interactions among disease, pesticides, water quality and adjacent land cover in amphibian habitats in the United States. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:320-332. [PMID: 27232962 DOI: 10.1016/j.scitotenv.2016.05.062] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/06/2016] [Accepted: 05/06/2016] [Indexed: 05/21/2023]
Abstract
To investigate interactions among disease, pesticides, water quality, and adjacent land cover, we collected samples of water, sediment, and frog tissue from 21 sites in 7 States in the United States (US) representing a variety of amphibian habitats. All samples were analyzed for >90 pesticides and pesticide degradates, and water and frogs were screened for the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) using molecular methods. Pesticides and pesticide degradates were detected frequently in frog breeding habitats (water and sediment) as well as in frog tissue. Fungicides occurred more frequently in water, sediment, and tissue than was expected based upon their limited use relative to herbicides or insecticides. Pesticide occurrence in water or sediment was not a strong predictor of occurrence in tissue, but pesticide concentrations in tissue were correlated positively to agricultural and urban land, and negatively to forested land in 2-km buffers around the sites. Bd was detected in water at 45% of sites, and on 34% of swabbed frogs. Bd detections in water were not associated with differences in land use around sites, but sites with detections had colder water. Frogs that tested positive for Bd were associated with sites that had higher total fungicide concentrations in water and sediment, but lower insecticide concentrations in sediments relative to frogs that were Bd negative. Bd concentrations on frog swabs were positively correlated to dissolved organic carbon, and total nitrogen and phosphorus, and negatively correlated to pH and water temperature. Data were collected from a range of locations and amphibian habitats and represent some of the first field-collected information aimed at understanding the interactions between pesticides, land use, and amphibian disease. These interactions are of particular interest to conservation efforts as many amphibians live in altered habitats and may depend on wetlands embedded in these landscapes to survive.
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Affiliation(s)
- W A Battaglin
- U.S. Geological Survey, Colorado Water Science Center, Lakewood, CO, United States
| | - K L Smalling
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ, United States
| | - C Anderson
- U.S. Geological Survey, Oregon Water Science Center, Portland, OR, United States
| | - D Calhoun
- U.S. Geological Survey South Atlantic Water Science Center, Atlanta, GA, United States
| | - T Chestnut
- National Park Service, Mount Rainer National Park, Ashford, WA, United States
| | - E Muths
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, United States
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Terrestrial Growth in Northern Leopard Frogs Reared in the Presence or Absence of Predators and Exposed to the Amphibian Chytrid Fungus at Metamorphosis. J HERPETOL 2016. [DOI: 10.1670/15-102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hanlon SM, Lynch KJ, Kerby JL, Parris MJ. The effects of a fungicide and chytrid fungus on anuran larvae in aquatic mesocosms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:12929-12940. [PMID: 25913318 DOI: 10.1007/s11356-015-4566-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 04/19/2015] [Indexed: 06/04/2023]
Abstract
The amphibian disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), has been linked to significant amphibian declines over the past three decades. The most severe effects of the pathogen have been primarily observed in relatively pristine areas that are not affected by many anthropogenic factors.One hypothesis concerning improved amphibian persistence with Bd in disturbed landscapes is that contaminants may abate the effects of Bd on amphibians. Recent laboratory studies have shown that pesticides, specifically the fungicide thiophanate-methyl (TM), can kill Bd outside of hosts and clear Bd infections within hosts. Using aquatic mesocosms, we tested the hypothesis that TM (0.43 mg/L) would alter growth and development of Lithobates sphenocephalus (southern leopard frog) tadpoles and Bd-infection loads in infected individuals. We hypothesized that the scope of such alterations and infection clearing would be affected by aquatic community variables, specifically zooplankton. TM altered zooplankton diversity (reduced cladoceran and increased copepod and ostracod abundances) and caused mortality to all tadpoles in TM-exposed tanks. In TM-free tanks, Bd-exposed tadpoles in high-density treatments metamorphosed smaller than Bd-unexposed, effects that were reversed in low-density treatments. Our study demonstrates the potential adverse effects of a fungicide and Bd on tadpoles and aquatic systems.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, TN, 38152, USA,
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Rumschlag SL, Boone MD. How Time of Exposure to the Amphibian Chytrid Fungus AffectsHyla chrysoscelisin the Presence of an Insecticide1. HERPETOLOGICA 2015. [DOI: 10.1655/herpetologica-d-13-00070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Buck JC, Hua J, Brogan WR, Dang TD, Urbina J, Bendis RJ, Stoler AB, Blaustein AR, Relyea RA. Effects of Pesticide Mixtures on Host-Pathogen Dynamics of the Amphibian Chytrid Fungus. PLoS One 2015; 10:e0132832. [PMID: 26181492 PMCID: PMC4504700 DOI: 10.1371/journal.pone.0132832] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 06/19/2015] [Indexed: 01/22/2023] Open
Abstract
Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often co-occur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batrachochytrium dendrobatidis (Bd), a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas) from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan) or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D) or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs). Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load. This result could have broad implications for risk assessment of amphibians; the outcome of exposure to multiple stressors may be unpredictable and can differ between species and life stages.
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Affiliation(s)
- Julia C. Buck
- Texas Research Institute for Environmental Studies, Sam Houston State University, Huntsville, Texas, United States of America
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jessica Hua
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - William R. Brogan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Trang D. Dang
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jenny Urbina
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Randall J. Bendis
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Aaron B. Stoler
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Andrew R. Blaustein
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Rick A. Relyea
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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Smalling KL, Reeves R, Muths E, Vandever M, Battaglin WA, Hladik ML, Pierce CL. Pesticide concentrations in frog tissue and wetland habitats in a landscape dominated by agriculture. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 502:80-90. [PMID: 25244036 DOI: 10.1016/j.scitotenv.2014.08.114] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 05/04/2023]
Abstract
Habitat loss and exposure to pesticides are likely primary factors contributing to amphibian decline in agricultural landscapes. Conservation efforts have attempted to restore wetlands lost through landscape modifications to reduce contaminant loads in surface waters and providing quality habitat to wildlife. The benefits of this increased wetland area, perhaps especially for amphibians, may be negated if habitat quality is insufficient to support persistent populations. We examined the presence of pesticides and nutrients in water and sediment as indicators of habitat quality and assessed the bioaccumulation of pesticides in the tissue of two native amphibian species Pseudacris maculata (chorus frogs) and Lithobates pipiens (leopard frogs) at six wetlands (3 restored and 3 reference) in Iowa, USA. Restored wetlands are positioned on the landscape to receive subsurface tile drainage water while reference wetlands receive water from overland run-off and shallow groundwater sources. Concentrations of the pesticides frequently detected in water and sediment samples were not different between wetland types. The median concentration of atrazine in surface water was 0.2 μg/L. Reproductive abnormalities in leopard frogs have been observed in other studies at these concentrations. Nutrient concentrations were higher in the restored wetlands but lower than concentrations thought lethal to frogs. Complex mixtures of pesticides including up to 8 fungicides, some previously unreported in tissue, were detected with concentrations ranging from 0.08 to 1,500 μg/kg wet weight. No significant differences in pesticide concentrations were observed between species, although concentrations tended to be higher in leopard frogs compared to chorus frogs, possibly because of differences in life histories. Our results provide information on habitat quality in restored wetlands that will assist state and federal agencies, landowners, and resource managers in identifying and implementing conservation and management actions for these and similar wetlands in agriculturally dominated landscapes.
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Affiliation(s)
- Kelly L Smalling
- US Geological Survey New Jersey Water Science Center, Lawrenceville, NJ, USA.
| | - Rebecca Reeves
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA, USA
| | - Erin Muths
- US Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | - Mark Vandever
- US Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | | | - Michelle L Hladik
- US Geological Survey, California Water Science Center, Sacramento, CA, USA
| | - Clay L Pierce
- US Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit, Ames, IA, USA
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Rumschlag SL, Boone MD, Fellers G. The effects of the amphibian chytrid fungus, insecticide exposure, and temperature on larval anuran development and survival. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:2545-50. [PMID: 25098758 DOI: 10.1002/etc.2707] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/12/2014] [Accepted: 08/01/2014] [Indexed: 05/02/2023]
Abstract
Chytridiomycosis, a disease caused by Batrachochytrium dendrobatidis (Bd), has been implicated as a cause of amphibian declines. Susceptibility may be influenced by environmental factors that suppress the immune response. The authors conducted a laboratory study to examine the effect of temperature, insecticide exposure, and Bd exposure during larval anuran development. The authors examined the consequences of exposure to Bd, an insecticide (carbaryl or malathion), and static or fluctuating temperature (15 °C, 20 °C, 25 °C, or 15 °C to 25 °C 72-h flux) on larval development through metamorphosis of the Pacific treefrog (Pseudacris regilla). High and fluctuating temperature had negative effects on survival in the presence of Bd. Insecticides inhibited the effects of Bd; time to tail resorption of Pacific treefrogs decreased when tadpoles were exposed to carbaryl. The present study indicates that abiotic factors may play a role in the host-pathogen interactions in this system.
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Wise RS, Rumschlag SL, Boone MD. Effects of amphibian chytrid fungus exposure on American toads in the presence of an insecticide. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:2541-2544. [PMID: 25099070 DOI: 10.1002/etc.2709] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/02/2014] [Accepted: 08/01/2014] [Indexed: 06/03/2023]
Abstract
Abiotic factors such as pesticides may alter the impact of a pathogen on hosts, which could have implications for host-pathogen interactions and may explain variation in disease outbreaks in nature. In the present laboratory experiment, American toad (Anaxyrus americanus) metamorphs were exposed to the amphibian chytrid fungal pathogen Batrachochytrium dendrobatidis (Bd) and environmentally relevant concentrations of the insecticide malathion to determine whether malathion altered the effects of Bd exposure on growth and survival of toad metamorphs. Exposure to Bd significantly decreased survival over the 51 d of the experiment, suggesting that Bd could reduce recruitment into the terrestrial life stage when exposure occurs at metamorphosis. Malathion did not impact survival, but a 12-h exposure at metamorphosis significantly reduced terrestrial growth. Toads that were exposed to both Bd and malathion showed a nonsignificant trend toward the smallest growth compared with other treatments. The present study suggests that Bd may pose a threat to American toads even though population declines have not been observed for this species; in addition, the presence of both the insecticide malathion and Bd could reduce terrestrial growth, which could have implications for lifetime fitness and suggests that environmental factors could play a role in pathogen impacts in nature.
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Affiliation(s)
- Rayona S Wise
- Department of Biology, Miami University, Oxford, Ohio, USA
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35
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Edge C, Thompson D, Hao C, Houlahan J. The response of amphibian larvae to exposure to a glyphosate-based herbicide (Roundup WeatherMax) and nutrient enrichment in an ecosystem experiment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2014; 109:124-32. [PMID: 25173748 DOI: 10.1016/j.ecoenv.2014.07.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 07/25/2014] [Accepted: 07/27/2014] [Indexed: 06/03/2023]
Abstract
Herbicides and fertilizers are widely used throughout the world and pose a threat to aquatic ecosystems. Using a replicated, whole ecosystem experiment in which 24 small wetlands were split in half with an impermeable barrier we tested whether exposure to a glyphosate-based herbicide, Roundup WeatherMax™, alone or in combination with nutrient enrichment has an effect on the survival, growth or development of amphibians. The herbicide was applied at one of two concentrations (low=210 μg a.e./L, high=2880 μg a.e./L) alone and in combination with nutrient enrichment to one side of wetlands and the other was left as an untreated control. Each treatment was replicated with six wetlands, and the experiment was repeated over two years. In the high glyphosate and nutrient enrichment treatment the survival of wood frog (Lithobates sylvaticus) larvae was lower in enclosures placed in situ on the treated sides than the control sides of wetlands. However, these results were not replicated in the second year of study and they were not observed in free swimming wood frog larvae in the wetlands. In all treatments, wood frog larvae on the treated sides of wetlands were slightly larger (<10%) than those on the control side, but no effect on development was observed. The most dramatic finding was that the abundance of green frog larvae (Lithobates clamitans) was higher on the treated sides than the control sides of wetlands in the herbicide and nutrient treatments during the second year of the study. The results observed in this field study indicate that caution is necessary when extrapolating results from artificial systems to predict effects in natural systems. In this experiment, the lack of toxicity to amphibian larvae was probably due to the fact the pH of the wetlands was relatively low and the presence of sediments and organic surfaces which would have mitigated the exposure duration.
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Affiliation(s)
- Christopher Edge
- Biology Department, University of New Brunswick, 100 Tucker Park Rd, Saint John, NB, Canada E2L4L5; Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St, Toronto, ON, Canada M5S3G5(1).
| | - Dean Thompson
- Great Lakes Forestry Center, Canadian Forest Service, Sault Ste. Marie, ON, Canada P6A2E5
| | - Chunyan Hao
- Laboratory Services Branch, Ontario Ministry of the Environment, Etobicoke
| | - Jeff Houlahan
- Biology Department, University of New Brunswick, 100 Tucker Park Rd, Saint John, NB, Canada E2L4L5
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Gaietto KM, Rumschlag SL, Boone MD. Effects of pesticide exposure and the amphibian chytrid fungus on gray treefrog (Hyla chrysoscelis) metamorphosis. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:2358-2362. [PMID: 25044296 DOI: 10.1002/etc.2689] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/01/2014] [Accepted: 07/10/2014] [Indexed: 06/03/2023]
Abstract
Pesticides are detectable in most aquatic habitats and have the potential to alter host-pathogen interactions. The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), has been associated with amphibian declines around the world. However, Bd-associated declines are more prominent in some areas, despite nearly global distribution of Bd, suggesting other factors contribute to disease outbreaks. In a laboratory study, the authors examined the effects of 6 different isolates of Bd in the presence or absence of a pesticide (the insecticide carbaryl or the fungicide copper sulfate) to recently hatched Cope's gray treefrog (Hyla chrysoscelis) tadpoles reared through metamorphosis. The authors found the presence or absence of pesticides differentially altered the mass at metamorphosis of tadpoles exposed to different Bd isolates, suggesting that isolate could influence metamorphosis but not in ways expected based on origin of the isolate. Pesticide exposure had the strongest impact on metamorphosis of all treatment combinations. Whereas copper sulfate exposure reduced the length of the larval period, carbaryl exposure had apparent positive effects by increasing mass at metamorphosis and lengthening larval period, which adds to evidence that carbaryl can stimulate development in counterintuitive ways. The present study provides limited support to the hypothesis that pesticides can alter the response of tadpoles to isolates of Bd and that the insecticide carbaryl can alter developmental decisions.
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Navarro-Martín L, Lanctôt C, Jackman P, Park BJ, Doe K, Pauli BD, Trudeau VL. Effects of glyphosate-based herbicides on survival, development, growth and sex ratios of wood frogs (Lithobates sylvaticus) tadpoles. I: chronic laboratory exposures to VisionMax®. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:278-90. [PMID: 24878356 DOI: 10.1016/j.aquatox.2014.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 05/07/2014] [Accepted: 05/13/2014] [Indexed: 05/06/2023]
Abstract
The purpose of this study was to determine if chronic exposure to the glyphosate-based herbicide VisionMax(®) affects the survival, development, growth, sex ratios and expression of specific genes involved in metamorphosis of wood frog tadpoles (Lithobates sylvaticus). We hypothesized that exposure to this herbicide will affect developmental rates by disrupting hormone pathways, sex ratios and/or gonadal morphology. Tadpoles were chronically exposed in the laboratory from Gosner developmental stage 25 to 42 to four different concentrations of VisionMax(®) (ranging from 0.021 to 2.9 mg acid equivalents/L). Chronic exposures to VisionMax(®) had direct effects on the metamorphosis of L. sylvaticus tadpoles by decreasing development rates, however, there was a decrease in survival only in the group exposed to the highest dose of VisionMax(®) (2.9 mg a.e./L; from approximately 96% in the control group to 77% in the treatment group). There was a decrease in the number of tadpoles reaching metamorphic climax, from 78% in the control group to 42% in the VisionMax(®) (2.9 mg a.e./L) group, and a 7-day delay to reach metamorphic climax in the same treatment group. No effects of exposure on sex ratios or gonadal morphology were detected in tadpoles exposed to any of the concentrations of VisionMax(®) tested. Gene expression analyses in brain and tail tissues demonstrated that exposure to VisionMax(®) alters the expression of key genes involved in development. Results showed significant interaction (two-way ANOVA, P<0.05) between developmental Gosner stage and treatment in brain corticotropin-releasing factor, deiodinase type II (dio2) and glucocorticotiroid receptor (grII) and tail dio2 and grII. This demonstrates that mRNA levels may be differently affected by treatment depending on the developmental stage at which they are assessed. At the same time there was a clear dose-response effect for VisionMax(®) to increase thyroid hormone receptor β in tadpole brain (F(2,69)=3.475, P=0.037) and tail (F(2,69)=27.569, P<0.001), regardless of developmental stage. Interestingly, delays in development (or survival) were only observed in the group exposed to 2.9 mg a.e./L of VisionMax(®), suggesting that tadpoles need to be exposed to a "threshold" concentration of glyphosate-based herbicide to exhibit phenotypic observable effects. We suggest that the upregulation of genes that trigger metamorphosis following VisionMax(®) herbicide exposure might result from a compensatory response for the delays in development observed. Further studies are needed to determine if disruption of expression of these key genes leads to long-term effects when metamorphs reach adult stages.
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Affiliation(s)
- L Navarro-Martín
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
| | - C Lanctôt
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
| | - P Jackman
- Atlantic Laboratory for Environmental Testing, Atlantic Region Environmental Science Centre, Environment Canada, Corner Morton Ave. & University Ave., Moncton, NB E1A 6S8, Canada.
| | - B J Park
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB R3T 2N6, Canada.
| | - K Doe
- Atlantic Laboratory for Environmental Testing, Atlantic Region Environmental Science Centre, Environment Canada, Corner Morton Ave. & University Ave., Moncton, NB E1A 6S8, Canada.
| | - B D Pauli
- National Wildlife Research Centre, Environment Canada, Carleton University, Raven Road, Ottawa, ON K1A 0H3, Canada.
| | - V L Trudeau
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
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Lanctôt C, Navarro-Martín L, Robertson C, Park B, Jackman P, Pauli BD, Trudeau VL. Effects of glyphosate-based herbicides on survival, development, growth and sex ratios of wood frog (Lithobates sylvaticus) tadpoles. II: agriculturally relevant exposures to Roundup WeatherMax® and Vision® under laboratory conditions. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:291-303. [PMID: 24912403 DOI: 10.1016/j.aquatox.2014.05.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/12/2014] [Accepted: 05/20/2014] [Indexed: 06/03/2023]
Abstract
Glyphosate-based herbicides are currently the most commonly used herbicides in the world. They have been shown to affect survival, growth, development and sexual differentiation of tadpoles under chronic laboratory exposures but this has not been investigated under more environmentally realistic conditions. The purpose of this study is (1) to determine if an agriculturally relevant exposure to Roundup WeatherMax®, a relatively new and understudied formulation, influences the development of wood frog tadpoles (Lithobates sylvaticus) through effects on the mRNA levels of genes involved in the control of metamorphosis; (2) to compare results to the well-studied Vision® formulation (containing the isopropylamine salt of glyphosate [IPA] and polyethoxylated tallowamine [POEA] surfactant) and to determine which ingredient(s) in the formulations are responsible for potential effects on development; and (3) to compare results to recent field studies that used a similar experimental design. In the present laboratory study, wood frog tadpoles were exposed to an agriculturally relevant application (i.e., two pulses) of Roundup WeatherMax® and Vision® herbicides as well as the active ingredient (IPA) and the POEA surfactant of Vision®. Survival, development, growth, sex ratios and mRNA levels of genes involved in tadpole metamorphosis were measured. Results show that Roundup WeatherMax® (2.89 mg acid equivalent (a.e.)/L) caused 100% mortality after the first pulse. Tadpoles treated with a lower concentration of Roundup WeatherMax® (0.21 mg a.e./L) as well as Vision® (2.89 mg a.e./L), IPA and POEA had an increased condition factor (based on length and weight measures in the tadpoles) relative to controls at Gosner stage (Gs) 36/38. At Gs42, tadpoles treated with IPA and POEA had a decreased condition factor. Also at Gs42, the effect on condition factor was dependent on the sex of tadpoles and significant treatment effects were only detected in males. In most cases, treatment reduced the normal mRNA increase of key genes controlling development in tadpoles between Gs37 and Gs42, such as genes encoding thyroid hormone receptor beta in brain, glucocorticoid receptor in tail and deiodinase enzyme in brain and tail. We conclude that glyphosate-based herbicides have the potential to alter mRNA profiles during metamorphosis. However, studies in natural systems have yet to replicate these negative effects, which highlight the need for more ecologically relevant studies for risk assessment.
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Affiliation(s)
- C Lanctôt
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - L Navarro-Martín
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - C Robertson
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - B Park
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, Manitoba R3T 2N6, Canada.
| | - P Jackman
- Environment Canada, Atlantic Laboratory for Environmental Testing, Moncton , New Brunswick E1A 3E9, Canada.
| | - B D Pauli
- Environment Canada, National Wildlife Research Center, Carleton University, Ottawa, Ontario K1A 0H3, Canada.
| | - V L Trudeau
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
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Rohr JR, Raffel TR, Halstead NT, McMahon TA, Johnson SA, Boughton RK, Martin LB. Early-life exposure to a herbicide has enduring effects on pathogen-induced mortality. Proc Biol Sci 2014; 280:20131502. [PMID: 24266041 DOI: 10.1098/rspb.2013.1502] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Exposure to stressors at formative stages in the development of wildlife and humans can have enduring effects on health. Understanding which, when and how stressors cause enduring health effects is crucial because these stressors might then be avoided or mitigated during formative stages to prevent lasting increases in disease susceptibility. Nevertheless, the impact of early-life exposure to stressors on the ability of hosts to resist and tolerate infections has yet to be thoroughly investigated. Here, we show that early-life, 6-day exposure to the herbicide atrazine (mean ± s.e.: 65.9±3.48 µg l(-1)) increased frog mortality 46 days after atrazine exposure (post-metamorphosis), but only when frogs were challenged with a chytrid fungus implicated in global amphibian declines. Previous atrazine exposure did not affect resistance of infection (fungal load). Rather, early-life exposure to atrazine altered growth and development, which resulted in exposure to chytrid at more susceptible developmental stages and sizes, and reduced tolerance of infection, elevating mortality risk at an equivalent fungal burden to frogs unexposed to atrazine. Moreover, there was no evidence of recovery from atrazine exposure. Hence, reducing early-life exposure of amphibians to atrazine could reduce lasting increases in the risk of mortality from a disease associated with worldwide amphibian declines. More generally, these findings highlight that a better understanding of how stressors cause enduring effects on disease susceptibility could facilitate disease prevention in wildlife and humans, an approach that is often more cost-effective and efficient than reactive medicine.
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Hanlon SM, Parris MJ. The interactive effects of chytrid fungus, pesticides, and exposure timing on gray treefrog (Hyla versicolor) larvae. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:216-22. [PMID: 24259231 DOI: 10.1002/etc.2419] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 07/04/2013] [Accepted: 10/01/2013] [Indexed: 06/02/2023]
Abstract
Aquatic organisms are often exposed to a wide variety of perturbations in nature, including pathogens and chemical contaminants. Despite the co-occurrence of these 2 stressors, few studies have examined the effects of chemical contaminants on host-pathogen dynamics. The authors tested the individual and combined effects on gray treefrog (Hyla versicolor) tadpoles of 2 commonly used pesticides (Roundup® and Sevin®) and the pathogenic fungus Batrachochytrium dendrobatidis (Bd). A fully factorial design was used, and tadpoles were exposed to Bd, Roundup, or Sevin alone, or a combination of Bd and either pesticide at 3 points during larval development (early, mid, late). It was predicted that pesticides would mediate the effect of Bd on tadpoles and reduce the likelihood of negative consequences of infection and that timing of exposure would influence these effects. Tadpoles exposed to Bd at the mid point experienced higher survival through metamorphosis than those exposed to Bd at the early or late points, while tadpoles exposed to Sevin at the early point experienced reduced survival compared with those exposed to Roundup or no-pesticide control at the same exposure point. Roundup ameliorated the effects of Bd on survival compared with tadpoles exposed to Bd alone, while there was no interactive effect of Sevin on survival. In addition, Sevin reduced mass of new metamorphs compared with Roundup and reduced snout-vent length compared with all other treatments. The present study supports the hypothesis that pesticides can mitigate the effects of Bd on amphibian hosts and that such effects may depend on the timing of exposure.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, Tennessee, USA
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41
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Smalling KL, Fellers GM, Kleeman PM, Kuivila KM. Accumulation of pesticides in Pacific chorus frogs (Pseudacris regilla) from California's Sierra Nevada Mountains, USA. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2013; 32:2026-34. [PMID: 23893497 DOI: 10.1002/etc.2308] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/28/2013] [Accepted: 04/30/2013] [Indexed: 05/07/2023]
Abstract
Pesticides are receiving increasing attention as potential causes of amphibian declines, acting singly or in combination with other stressors, but limited information is available on the accumulation of current-use pesticides in tissue. The authors examined potential exposure and accumulation of currently used pesticides in pond-breeding frogs (Pseudacris regilla) collected from 7 high elevations sites in northern California. All sites sampled are located downwind of California's highly agricultural Central Valley and receive inputs of pesticides through precipitation and/or dry deposition. Whole frog tissue, water, and sediment were analyzed for more than 90 current-use pesticides and pesticide degradates using gas chromatography-mass spectrometry. Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected pesticides in tissue samples. Median pesticide concentration ranged from 13 µg/kg to 235 µg/kg wet weight. Tebuconazole and pyraclostrobin were the only 2 compounds observed frequently in frog tissue and sediment. Significant spatial differences in tissue concentration were observed, which corresponded to pesticide use in the upwind counties. Data generated indicated that amphibians residing in remote locations are exposed to and capable of accumulating current-use pesticides. A comparison of P. regilla tissue concentrations with water and sediment data indicated that the frogs are accumulating pesticides and are potentially a more reliable indicator of exposure to this group of pesticides than either water or sediment.
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Affiliation(s)
- Kelly L Smalling
- California Water Science Center, US Geological Survey, Sacramento, CA, USA.
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Wagner N, Reichenbecher W, Teichmann H, Tappeser B, Lötters S. Questions concerning the potential impact of glyphosate-based herbicides on amphibians. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2013; 32:1688-700. [PMID: 23637092 DOI: 10.1002/etc.2268] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/20/2013] [Accepted: 04/24/2013] [Indexed: 06/02/2023]
Abstract
Use of glyphosate-based herbicides is increasing worldwide. The authors review the available data related to potential impacts of these herbicides on amphibians and conduct a qualitative meta-analysis. Because little is known about environmental concentrations of glyphosate in amphibian habitats and virtually nothing is known about environmental concentrations of the substances added to the herbicide formulations that mainly contribute to adverse effects, glyphosate levels can only be seen as approximations for contamination with glyphosate-based herbicides. The impact on amphibians depends on the herbicide formulation, with different sensitivity of taxa and life stages. Effects on development of larvae apparently are the most sensitive endpoints to study. As with other contaminants, costressors mainly increase adverse effects. If and how glyphosate-based herbicides and other pesticides contribute to amphibian decline is not answerable yet due to missing data on how natural populations are affected. Amphibian risk assessment can only be conducted case-specifically, with consideration of the particular herbicide formulation. The authors recommend better monitoring of both amphibian populations and contamination of habitats with glyphosate-based herbicides, not just glyphosate, and suggest including amphibians in standardized test batteries to study at least dermal administration.
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Affiliation(s)
- Norman Wagner
- Biogeography Department, Trier University, Trier, Germany.
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43
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Paetow LJ, McLaughlin JD, Pauli BD, Marcogliese DJ. Mortality of American bullfrog tadpoles Lithobates catesbeianus infected by Gyrodactylus jennyae and experimentally exposed to Batrachochytrium dendrobatidis. JOURNAL OF AQUATIC ANIMAL HEALTH 2013; 25:15-26. [PMID: 23290030 DOI: 10.1080/08997659.2012.722170] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis in postmetamorphic amphibians, has been linked to amphibian population declines. Different amphibian species, however, exhibit different susceptibility to Bd pathogenicity. At the same time, agricultural pesticides commonly found contaminating aquatic habitats have been reported to increase the susceptibility of amphibians to pathogens. To investigate whether certain pesticides are able to alter the pathogenicity of Bd to larval amphibians, we exposed larval American bullfrogs Lithobates catesbeianus to end-use formulations of the herbicides atrazine or glyphosate, and then exposed them to Bd. Following the experimental exposures, a preexisting infection of the tadpoles by the monogenean ectoparasite Gyrodactylus jennyae was detected in all experimental and control tadpoles. Gyrodactylus jennyae infection intensity varied, and individuals with heavy G. jennyae infections suffered more skin erosion due to grazing by the parasite. Tadpoles experimentally exposed to Bd, or to Bd and either herbicide, had significantly reduced survival rates compared with untreated tadpoles that were only infected by G. jennyae. Increased mortality was also correlated with degree of skin erosion; survival of tadpoles with severe skin erosion was significantly reduced compared with that of tadpoles with no, or mild, skin erosion. While infected with G. jennyae, the group of tadpoles with the lowest survival rate (exposed only to Bd) included significantly more individuals exhibiting severe skin erosion and significantly fewer individuals without skin erosion, compared with the control group. These results emphasize the potential pathogenicity of gyrodactylid infections in larval amphibian hosts and suggest that concomitant exposures to Bd may enhance infections and effects of G. jennyae in bullfrog tadpoles.
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Affiliation(s)
- Linda J Paetow
- Department of Biology, Concordia University, Montreal, Canada.
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44
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Edge CB, Gahl MK, Thompson DG, Houlahan JE. Laboratory and field exposure of two species of juvenile amphibians to a glyphosate-based herbicide and Batrachochytrium dendrobatidis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 444:145-52. [PMID: 23262329 DOI: 10.1016/j.scitotenv.2012.11.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 10/22/2012] [Accepted: 11/10/2012] [Indexed: 06/01/2023]
Abstract
Herbicides are commonly used in agriculture and silviculture to reduce interspecific competition among plants and thereby enhance crop growth, quality, and volume. Internationally, formulations of glyphosate-based herbicides are the most widely used herbicides in both these sectors. A large amount of work has focused on the effects of these herbicides on amphibians. Several laboratory and mesocosm studies have demonstrated that various formulations of glyphosate herbicides can be acutely toxic to larval and juvenile amphibians at concentrations at the upper end of environmental realism. However, to date there has been little work done investigating such effects in natural systems, limited work on juvenile amphibians, and only a few studies have investigated interactions with other stressors. We conducted a 16 day field experiment in which juveniles of two amphibian species (Lithobates clamitans and Lithobates pipiens) were exposed to the herbicide Roundup WeatherMax™ at four application rates (0, 2.16, 4.32 and 8.64 kg a.e./ha) to investigate effects on survival, liver somatic index (LSI), body condition, and incidence of disease caused by Batrachochytrium dendrobatidis (Bd). In a separate 16 day laboratory experiment, we exposed juvenile L. clamitans to both the herbicide and Bd. Results of our studies showed that this particular herbicide formulation had no effect on juvenile survival, LSI, body condition, or disease incidence, nor was there an interaction between exposure to herbicide and exposure to the disease in tests which closely mimic real world exposure scenarios. These experiments suggest that Roundup WeatherMax as typically used in agriculture is unlikely to cause significant deleterious effects on juvenile amphibians under real world exposure conditions.
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Affiliation(s)
- Christopher B Edge
- Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada.
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45
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Moreira JC, Peres F, Simões AC, Pignati WA, Dores EDC, Vieira SN, Strüssmann C, Mott T. [Groundwater and rainwater contamination by pesticides in an agricultural region of Mato Grosso state in central Brazil]. CIENCIA & SAUDE COLETIVA 2012; 17:1557-68. [PMID: 22699646 DOI: 10.1590/s1413-81232012000600019] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 04/24/2012] [Indexed: 11/22/2022] Open
Abstract
This study sought to analyze groundwater and rainwater contamination by pesticides in two municipalities (Lucas do Rio Verde and Campo Verde) of Mato Grosso state. The area is Brazil's mid-west situated among the major soybean, corn and cotton producers in the state and the country. The analytical methodology combined chromatographic techniques on groundwater and rainwater samples with eco-toxicological analyses of the impacts of contamination by pesticide on bio-indicator species. The results revealed the presence of different pesticide residues in the groundwater and rainwater samples collected in the two municipalities. In conjunction with this data, results of the eco-toxicological tests revealed the presence of anomalies in a bio-indicator species collected in one of the two study sites compatible with exposure to pesticides. The results presented and discussed here highlight the degradation of water resources in the region, caused by the intensive use of pesticides in agriculture, including the contamination of drinking water sources and rain, broadening the risk of contamination beyond the cultivated areas.
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Affiliation(s)
- Josino Costa Moreira
- Centro de Estudos da Saúde do Trabalhador e Ecologia Humana, Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, 21041-210 Rio de Janeiro, RJ.
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46
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Edge CB, Thompson DG, Hao C, Houlahan JE. A silviculture application of the glyphosate-based herbicide VisionMAX to wetlands has limited direct effects on amphibian larvae. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:2375-83. [PMID: 22833320 DOI: 10.1002/etc.1956] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 06/12/2012] [Accepted: 06/15/2012] [Indexed: 06/01/2023]
Abstract
Herbicides are commonly used in agriculture and silviculture to reduce interspecific competition among plants and thereby enhance crop growth, quality, and volume. Internationally, glyphosate-based herbicides are the most widely used herbicides in both of these sectors. Laboratory and mesocosm studies have demonstrated that some formulations are toxic to amphibian larvae below concentrations that approximate predicted maximal or "worst-case" exposure scenarios. However, field studies have not found evidence of toxicity at these concentrations. The authors conducted a replicated field experiment involving 10 naturalized wetlands split in half with an impermeable plastic barrier to assess the direct toxicity of a glyphosate formulation commonly used in silviculture (VisionMAX™). The herbicide formulation was applied directly to the surface of one side of each wetland at one of two target aqueous exposure rates (high = 2,880, low = 550 µg acid equivalents [a.e.]/L), and the other side was left as an untreated control. The survival and growth of green frog larvae (Lithobates clamitans) were assessed for two years following herbicide treatment. The herbicide did not have a negative impact on survival or growth of L. clamitans larvae at either treatment level. In fact, mean larval abundance was typically greater in the treated sides than in control sides within the year of herbicide application. These results indicate that typical silviculture use of VisionMAX poses negligible risk to larval amphibians, likely because the combined effects of sorption and degradation in natural wetlands limit the exposure magnitude and duration.
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Affiliation(s)
- Christopher B Edge
- Biology Department, University of New Brunswick, Saint John, New Brunswick, Canada.
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47
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Greenspan SE, Longcore JE, Calhoun AJK. Host invasion by Batrachochytrium dendrobatidis: fungal and epidermal ultrastructure in model anurans. DISEASES OF AQUATIC ORGANISMS 2012; 100:201-10. [PMID: 22968788 DOI: 10.3354/dao02483] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The chytridiomycete fungus Batrachochytrium dendrobatidis (Bd) colonizes mouthparts of amphibian larvae and superficial epidermis of post-metamorphic amphibians, causing the disease chytridiomycosis. Fungal growth within host cells has been documented by light and transmission electron microscopy; however, entry of the fungus into host cells has not. Our objective was to document how Bd enters host cells in the wood frog Lithobates sylvaticus, a species at high mortality risk for chytridiomycosis, and the bullfrog L. catesbeianus, a species at low mortality risk for chytridiomycosis. We inoculated frogs and documented infection with transmission electron microscopy. Zoospores encysted on the skin surface and produced morphologically similar germination tubes in both host species that penetrated host cell membranes and enabled transfer of zoospore contents into host cells. Documenting fungal and epidermal ultrastructure during host invasion furthers our understanding of Bd development and the pathogenesis of chytridiomycosis.
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Affiliation(s)
- Sasha E Greenspan
- Ecology and Environmental Science Program, School of Biology and Ecology, University of Maine, Orono, Maine 04469, USA.
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48
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Hanlon SM, Parris MJ. The impact of pesticides on the pathogen Batrachochytrium dendrobatidis independent of potential hosts. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2012; 63:137-43. [PMID: 22228138 DOI: 10.1007/s00244-011-9744-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 12/19/2011] [Indexed: 05/31/2023]
Abstract
Amphibians around the world are experiencing the greatest organismal decline in recent history. Xenobiotics, such as pesticides, and pathogenic biotic perturbations, including the fungus Batrachochytrium dendrobatidis (Bd), have played major roles in amphibian decreases. We conducted laboratory culture studies to determine the effects of three pesticides {carbaryl, glyphosate, and thiophanate-methyl [TM; Topsin-M(R) (Cerexagri-Nisso LLC)]} on Bd zoospore production and zoosporangia growth. We applied Bd to pesticides mixed in an agar culture to simulate pathogen introduction to a system with pre-existing pesticides (Bd addition). Alternatively, pesticides were applied to pre-established Bd to simulate pesticide introduction after Bd establishment (pesticide addition). We then measured Bd zoosporangia and zoospore production. All pesticides significantly inhibited zoospore production; however, glyphosate and TM were more effective at doing so than carbaryl. In addition, only carbaryl and glyphosate inhibited zoosporangia production. Our data suggest that carbaryl and glyphosate are equally effective at inhibiting both zoosporangia and zoospore production; however, TM is selectively toxic to zoospores but not zoosporangia. One possible explanation for this observation could be that TM is toxic to zoospores but not the protective zoosporangia. In the case of pesticides applied to established Bd cultures, all pesticides caused significant mortality in both zoosporangia and zoospores, and no differences were found among pesticides. We conclude that examining pesticide and pathogen interactions independent of hosts provides mechanistic understanding of such interactions before and after host infection or contamination.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, TN 38152-3530, USA.
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49
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Paetow LJ, Daniel McLaughlin J, Cue RI, Pauli BD, Marcogliese DJ. Effects of herbicides and the chytrid fungus Batrachochytrium dendrobatidis on the health of post-metamorphic northern leopard frogs (Lithobates pipiens). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 80:372-80. [PMID: 22520452 DOI: 10.1016/j.ecoenv.2012.04.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 04/02/2012] [Accepted: 04/03/2012] [Indexed: 05/31/2023]
Abstract
Effects of exposure to contaminants such as pesticides along with exposure to pathogens have been listed as two major contributors to the global crisis of declining amphibian populations. These two factors have also been linked in explanations of the causes of these population declines. We conducted a combined exposure experiment to test the hypothesis that exposure to two agricultural herbicides would increase the susceptibility of post-metamorphic northern leopard frogs (Lithobates pipiens) to the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd). We assessed the independent and interactive effects of these exposures on the health and survival of the frogs. Wild-caught frogs underwent a 21-day exposure to a nominal concentration of either 2.1 μg/L atrazine (Aatrex(®) Liquid 480) or 100 μg a.e./L glyphosate (Roundup(®) Original), followed by Bd, and then were observed until 94 days post-initial exposure to the herbicides. Actual levels of atrazine were between 4.28 ± 0.04 μg/L and 1.70 ± 0.26 μg/L while glyphosate degraded from 100 μg a.e./L to approximately 7 μg a.e./L within 6 days of initial exposure to the herbicides. Compared to controls, the glyphosate formulation reduced the snout-vent length of frogs during the pesticide exposure (at Day 21), and the atrazine formulation reduced gain in mass up to Day 94. No treatment affected survival, splenosomatic or hepatosomatic indices, the densities and sizes of hepatic and splenic melanomacrophage aggregates, the density and size of hepatic granulomas, proportions of circulating leucocytes, the ratio of neutrophils to lymphocytes, or the ratio of leucocytes to erythrocytes. Histological assessment of samples collected at Day 94 revealed no evidence of Bd infection in any Bd-exposed frogs, while real-time PCR detected only one case of light infection in a single atrazine- and Bd-exposed frog. Frogs exposed to Bd shed their skin significantly more frequently than Bd-unexposed frogs, which may have helped them resist or clear infection, and could explain why no interaction between the herbicides and Bd was detected. The results suggest that these frogs were resistant to Bd infection and that pre-exposure to the herbicides did not alter this resistance. The effects seen on the growth following herbicide exposure is a concern, as reduced growth can lower the reproductive success and survival of the amphibians.
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Affiliation(s)
- Linda J Paetow
- Department of Biology, Concordia University, 7141 Sherbrooke St. W., Montreal, Quebec, Canada H4B 1R6
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50
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Gahl MK, Longcore JE, Houlahan JE. Varying responses of northeastern North American amphibians to the chytrid pathogen Batrachochytrium dendrobatidis. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2012; 26:135-41. [PMID: 22181933 DOI: 10.1111/j.1523-1739.2011.01801.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is widespread among amphibians in northeastern North America. It is unknown, however, whether Bd has the potential to cause extensive amphibian mortalities in northeastern North America as have occurred elsewhere. In the laboratory, we exposed seven common northeastern North American amphibian species to Bd to assess the likelihood of population-level effects from the disease. We exposed larval wood frogs (Lithobates sylvaticus) and postmetamorphic frogs of six other species to two different strains of Bd, a northeastern strain (JEL404) and a strain that caused die-offs of amphibians in Panama (JEL423), under ideal in vitro growth conditions for Bd. Exposed American toads (Anaxyrus americanus) all died; thus, this species may be the most likely to die from Bd-caused disease in the wild. Both Bd strains were associated with mortalities of wood frogs, although half the metamorphs survived. The Bd strain from Panama killed metamorphic green frogs (L. clamitans), whereas the northeastern strain did not, which means novel strains of Bd may lead to death even when local strains may not. No mortality was observed in four species (bullfrogs [L. catesbeianus], northern leopard frogs [L. pipiens], spring peepers [Pseudacris crucifer], and blue-spotted salamanders [Ambystoma laterale]) and in some individuals of green frogs and wood frogs that we exposed. This finding suggests these six species may be Bd vectors. Our results show that systematic exposures of amphibian species to Bd in the laboratory may be a good first step in the identification of species susceptible to Bd-caused declines and in directing regional conservation efforts aimed at susceptible species.
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Affiliation(s)
- Megan K Gahl
- Department of Biology, Canadian Rivers Institute, University of New Brunswick, P.O. Box 5050, St. John, New Brunswick, E2L 4L5, Canada.
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