Reptiles as potential vectors and hosts of the amphibian pathogen Batrachochytrium dendrobatidis in Panama.

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Kilburn, Vanessa L; Ibáñez, Roberto; Green, David M

2011-12-06

Chytridiomycosis, the disease caused by Batrachochytrium dendrobatidis, is considered to be a disease exclusively of amphibians. However, B. dendrobatidis may also be capable of persisting in the environment, and non-amphibian vectors or hosts may contribute to disease transmission. Reptiles living in close proximity to amphibians and sharing similar ecological traits could serve as vectors or reservoir hosts for B. dendrobatidis, harbouring the organism on their skin without succumbing to disease. We surveyed for the presence of B. dendrobatidis DNA among 211 lizards and 8 snakes at 8 sites at varying elevations in Panama where the syntopic amphibians were at pre-epizootic, epizootic or post-epizootic stages of chytridiomycosis. Detection of B. dendrobatidis DNA was done using qPCR analysis. Evidence of the amphibian pathogen was present at varying intensities in 29 of 79 examined Anolis humilis lizards (32%) and 9 of 101 A. lionotus lizards (9%), and in one individual each of the snakes Pliocercus euryzonus, Imantodes cenchoa, and Nothopsis rugosus. In general, B. dendrobatidis DNA prevalence among reptiles was positively correlated with the infection prevalence among co-occurring anuran amphibians at any particular site (r = 0.88, p = 0.004). These reptiles, therefore, may likely be vectors or reservoir hosts for B. dendrobatidis and could serve as disease transmission agents. Although there is no evidence of B. dendrobatidis disease-induced declines in reptiles, cases of coincidence of reptile and amphibian declines suggest this potentiality. Our study is the first to provide evidence of non-amphibian carriers for B. dendrobatidis in a natural Neotropical environment.

Amphibians Testing Negative for Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans on the Qinghai-Tibetan Plateau, China

Institute of Scientific and Technical Information of China (English)

Supen WANG; Wei ZHU; Liqing FAN; Jiaqi LI; Yiming LI

2017-01-01

A disease caused by the fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) is responsible for recent worldwide declines and extinctions of amphibian populations.The Qinghai-Tibetan Plateau (QTP) is aglobal biodiversity hotspot,yet little is known about the prevalence of Bd and Bsal in this region.In this study,we collected 336 non-invasive skin swabs from wild amphibians (including an exotic amphibian species) on the QTP.In addition,to assess the historical prevalence of Bd and Bsal on the QTP,we collected 117 non-invasive skin swabs from museum-archived amphibian samples (from 1964-1982) originating from the QTP.Our results showed all samples to be negative for Bd and Bsal.The government should ban the potentially harmful introduction of non-native amphibian species to the QTP and educate the public about the impacts of releasing exotic amphibians from chytrid-infected areas into native environments of the QTP.

Inhibition of Fungal Pathogens across Genotypes and Temperatures by Amphibian Skin Bacteria

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Carly R. Muletz-Wolz

2017-08-01

Full Text Available Symbiotic bacteria may dampen the impacts of infectious diseases on hosts by inhibiting pathogen growth. However, our understanding of the generality of pathogen inhibition by different bacterial taxa across pathogen genotypes and environmental conditions is limited. Bacterial inhibitory properties are of particular interest for the amphibian-killing fungal pathogens (Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, for which probiotic applications as conservation strategies have been proposed. We quantified the inhibition strength of five putatively B. dendrobatidis-inhibitory bacteria isolated from woodland salamander skin against six Batrachochytrium genotypes at two temperatures (12 and 18°C. We selected six genotypes from across the Batrachochytrium phylogeny: B. salamandrivorans, B. dendrobatidis-Brazil and four genotypes of the B. dendrobatidis Global Panzootic Lineage (GPL1: JEL647, JEL404; GPL2: SRS810, JEL423. We performed 96-well plate challenge assays in a full factorial design. We detected a Batrachochytrium genotype by temperature interaction on bacterial inhibition score for all bacteria, indicating that bacteria vary in ability to inhibit Batrachochytrium depending on pathogen genotype and temperature. Acinetobacter rhizosphaerae moderately inhibited B. salamandrivorans at both temperatures (μ = 46–53%, but not any B. dendrobatidis genotypes. Chryseobacterium sp. inhibited three Batrachochytrium genotypes at both temperatures (μ = 5–71%. Pseudomonas sp. strain 1 inhibited all Batrachochytrium genotypes at 12°C and four Batrachochytrium genotypes at 18°C (μ = 5–100%. Pseudomonas sp. strain 2 and Stenotrophomonas sp. moderately to strongly inhibited all six Batrachochytrium genotypes at both temperatures (μ = 57–100%. All bacteria consistently inhibited B. salamandrivorans. Using cluster analysis of inhibition scores, we found that more closely related Batrachochytrium genotypes grouped together

Predicting the potential distribution of the amphibian pathogen Batrachochytrium dendrobatidis in East and Southeast Asia.

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Moriguchi, Sachiko; Tominaga, Atsushi; Irwin, Kelly J; Freake, Michael J; Suzuki, Kazutaka; Goka, Koichi

2015-04-08

Batrachochytrium dendrobatidis (Bd) is the pathogen responsible for chytridiomycosis, a disease that is associated with a worldwide amphibian population decline. In this study, we predicted the potential distribution of Bd in East and Southeast Asia based on limited occurrence data. Our goal was to design an effective survey area where efforts to detect the pathogen can be focused. We generated ecological niche models using the maximum-entropy approach, with alleviation of multicollinearity and spatial autocorrelation. We applied eigenvector-based spatial filters as independent variables, in addition to environmental variables, to resolve spatial autocorrelation, and compared the model's accuracy and the degree of spatial autocorrelation with those of a model estimated using only environmental variables. We were able to identify areas of high suitability for Bd with accuracy. Among the environmental variables, factors related to temperature and precipitation were more effective in predicting the potential distribution of Bd than factors related to land use and cover type. Our study successfully predicted the potential distribution of Bd in East and Southeast Asia. This information should now be used to prioritize survey areas and generate a surveillance program to detect the pathogen.

Differences in sensitivity to the fungal pathogen Batrachochytrium dendrobatidis among amphibian populations.

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Bradley, Paul W; Gervasi, Stephanie S; Hua, Jessica; Cothran, Rickey D; Relyea, Rick A; Olson, Deanna H; Blaustein, Andrew R

2015-10-01

Contributing to the worldwide biodiversity crisis are emerging infectious diseases, which can lead to extirpations and extinctions of hosts. For example, the infectious fungal pathogen Batrachochytrium dendrobatidis (Bd) is associated with worldwide amphibian population declines and extinctions. Sensitivity to Bd varies with species, season, and life stage. However, there is little information on whether sensitivity to Bd differs among populations, which is essential for understanding Bd-infection dynamics and for formulating conservation strategies. We experimentally investigated intraspecific differences in host sensitivity to Bd across 10 populations of wood frogs (Lithobates sylvaticus) raised from eggs to metamorphosis. We exposed the post-metamorphic wood frogs to Bd and monitored survival for 30 days under controlled laboratory conditions. Populations differed in overall survival and mortality rate. Infection load also differed among populations but was not correlated with population differences in risk of mortality. Such population-level variation in sensitivity to Bd may result in reservoir populations that may be a source for the transmission of Bd to other sensitive populations or species. Alternatively, remnant populations that are less sensitive to Bd could serve as sources for recolonization after epidemic events. © 2015 Society for Conservation Biology.

Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Wild Amphibian Populations in Madagascar

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Kolby, Jonathan E.; Smith, Kristine M.; Ramirez, Sara D.; Rabemananjara, Falitiana; Pessier, Allan P.; Brunner, Jesse L.; Goldberg, Caren S.; Berger, Lee; Skerratt, Lee F.

2015-01-01

We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by disease

Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis and Ranavirus in Wild Amphibian Populations in Madagascar.

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Jonathan E Kolby

Full Text Available We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by

Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Wild Amphibian Populations in Madagascar.

Science.gov (United States)

Kolby, Jonathan E; Smith, Kristine M; Ramirez, Sara D; Rabemananjara, Falitiana; Pessier, Allan P; Brunner, Jesse L; Goldberg, Caren S; Berger, Lee; Skerratt, Lee F

2015-01-01

We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by disease

Pathogenic fungus Batrachochytrium dendrobatidis in marbled water frog Telmatobius marmoratus: first record from Lake Titicaca, Bolivia.

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Cossel, John; Lindquist, Erik; Craig, Heather; Luthman, Kyle

2014-11-13

The pathogenic fungus Batrachochytrium dendrobatidis (Bd) has been associated with amphibian declines worldwide but has not been well-studied among Critically Endangered amphibian species in Bolivia. We sampled free-living marbled water frogs Telmatobius marmoratus (Anura: Leptodactylidae) from Isla del Sol, Bolivia, for Bd using skin swabs and quantitative polymerase chain reactions. We detected Bd on 44% of T. marmoratus sampled. This is the first record of Bd in amphibians from waters associated with Lake Titicaca, Bolivia. These results further confirm the presence of Bd in Bolivia and substantiate the potential threat of this pathogen to the Critically Endangered, sympatric Titicaca water frog T. culeus and other Andean amphibians.

Effects of an infectious fungus, Batrachochytrium dendrobatidis, on amphibian predator-prey interactions.

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Barbara A Han

2011-02-01

Full Text Available The effects of parasites and pathogens on host behaviors may be particularly important in predator-prey contexts, since few animal behaviors are more crucial for ensuring immediate survival than the avoidance of lethal predators in nature. We examined the effects of an emerging fungal pathogen of amphibians, Batrachochytrium dendrobatidis, on anti-predator behaviors of tadpoles of four frog species. We also investigated whether amphibian predators consumed infected prey, and whether B. dendrobatidis caused differences in predation rates among prey in laboratory feeding trials. We found differences in anti-predator behaviors among larvae of four amphibian species, and show that infected tadpoles of one species (Anaxyrus boreas were more active and sought refuge more frequently when exposed to predator chemical cues. Salamander predators consumed infected and uninfected tadpoles of three other prey species at similar rates in feeding trials, and predation risk among prey was unaffected by B. dendrobatidis. Collectively, our results show that even sub-lethal exposure to B. dendrobatidis can alter fundamental anti-predator behaviors in some amphibian prey species, and suggest the unexplored possibility that indiscriminate predation between infected and uninfected prey (i.e., non-selective predation could increase the prevalence of this widely distributed pathogen in amphibian populations. Because one of the most prominent types of predators in many amphibian systems is salamanders, and because salamanders are susceptible to B. dendrobatidis, our work suggests the importance of considering host susceptibility and behavioral changes that could arise from infection in both predators and prey.

Coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen Batrachochytrium dendrobatidis.

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Cheng, Tina L; Rovito, Sean M; Wake, David B; Vredenburg, Vance T

2011-06-07

Amphibians highlight the global biodiversity crisis because ∼40% of all amphibian species are currently in decline. Species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, Bufo periglenes, from Costa Rica). The emergence of a fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether Bd emergence was linked to earlier declines and extinctions. We describe a noninvasive PCR sampling technique that detects Bd in formalin-preserved museum specimens. We detected Bd by PCR in 83-90% (n = 38) of samples that were identified as positive by histology. We examined specimens collected before, during, and after major amphibian decline events at established study sites in southern Mexico, Guatemala, and Costa Rica. A pattern of Bd emergence coincident with decline at these localities is revealed-the absence of Bd over multiple years at all localities followed by the concurrent emergence of Bd in various species at each locality during a period of population decline. The geographical and chronological emergence of Bd at these localities also indicates a southbound spread from southern Mexico in the early 1970s to western Guatemala in the 1980s/1990s and to Monteverde, Costa Rica by 1987. We find evidence of a historical "Bd epidemic wave" that began in Mexico and subsequently spread to Central America. We describe a technique that can be used to screen museum specimens from other amphibian decline sites around the world.

Batrachochytrium dendrobatidis prevalence and haplotypes in domestic and imported pet amphibians in Japan.

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Tamukai, Kenichi; Une, Yumi; Tominaga, Atsushi; Suzuki, Kazutaka; Goka, Koichi

2014-05-13

The international trade in amphibians is believed to have increased the spread of Batrachochytrium dendrobatidis (Bd), the fungal pathogen responsible for chytridiomycosis, which has caused a rapid decline in amphibian populations worldwide. We surveyed amphibians imported into Japan and those held in captivity for a long period or bred in Japan to clarify the Bd infection status. Samples were taken from 820 individuals of 109 amphibian species between 2008 and 2011 and were analyzed by a nested-PCR assay. Bd prevalence in imported amphibians was 10.3% (58/561), while it was 6.9% (18/259) in those in private collections and commercially bred amphibians in Japan. We identified the genotypes of this fungus using partial DNA sequences of the internal transcribed spacer (ITS) region. Sequencing of PCR products of all 76 Bd-positive samples revealed 11 haplotypes of the Bd ITS region. Haplotype A (DNA Data Bank of Japan accession number AB435211) was found in 90% (52/58) of imported amphibians. The results show that Bd is currently entering Japan via the international trade in exotic amphibians as pets, suggesting that the trade has indeed played a major role in the spread of Bd.

Widespread presence of the pathogenic fungus Batrachochytrium dendrobatidis in wild amphibian communities in Madagascar

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Bletz, Molly C.; Rosa, Gonçalo M.; Andreone, Franco; Courtois, Elodie A.; Schmeller, Dirk S.; Rabibisoa, Nirhy H. C.; Rabemananjara, Falitiana C. E.; Raharivololoniaina, Liliane; Vences, Miguel; Weldon, Ché; Edmonds, Devin; Raxworthy, Christopher J.; Harris, Reid N.; Fisher, Matthew C.; Crottini, Angelica

2015-01-01

Amphibian chytridiomycosis, an emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), has been a significant driver of amphibian declines. While globally widespread, Bd had not yet been reported from within Madagascar. We document surveys conducted across the country between 2005 and 2014, showing Bd's first record in 2010. Subsequently, Bd was detected in multiple areas, with prevalence reaching up to 100%. Detection of Bd appears to be associated with mid to high elevation sites and to have a seasonal pattern, with greater detectability during the dry season. Lineage-based PCR was performed on a subset of samples. While some did not amplify with any lineage probe, when a positive signal was observed, samples were most similar to the Global Panzootic Lineage (BdGPL). These results may suggest that Bd arrived recently, but do not exclude the existence of a previously undetected endemic Bd genotype. Representatives of all native anuran families have tested Bd-positive, and exposure trials confirm infection by Bd is possible. Bd's presence could pose significant threats to Madagascar's unique “megadiverse” amphibians. PMID:25719857

Low prevalence of chytrid fungus (Batrachochytrium dendrobatidis) in amphibians of U.S

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Blake R. Hossack; Michael J. Adams; Evan H. Campbell Grant; Christopher A. Pearl; James B. Bettaso; William J. Barichivich; Winsor H. Lowe; Kimberly True; Joy L. Ware; Paul Stephen Corn

2010-01-01

Many declines of amphibian populations have been associated with chytridiomycosis, a disease caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd). Despite the relatively high prevalence of chytridiomycosis in stream amphibians globally, most surveys in North America have focused primarily on wetland-associated species, which are frequently infected. To...

Efficacy of SYBR 14/propidium iodide viability stain for the amphibian chytrid fungus Batrachochytrium dendrobatidis.

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Stockwell, M P; Clulow, J; Mahony, M J

2010-01-25

The amphibian chytrid fungus Batrachochytrium dendrobatidis is a recently described pathogen that has been implicated as a causal agent in the global decline in amphibians. Research into its biology and epidemiology has frequently involved in vitro experimentation. However, this research is currently limited by the inability to differentiate between viable and inviable zoospores. Stains are frequently used to determine cell viability, and this study tested a 2-colour fluorescence assay for the detection and quantification of viable B. dendrobatidis zoospores. The results show that the nucleic acid stains SYBR 14 and propidium iodide are effective in distinguishing live from dead zoospores, and a protocol has been optimized for their use. This viability assay provides an efficient and reliable tool that will have applications in B. dendrobatidis challenge and amphibian exposure experiments.

Projecting the Global Distribution of the Emerging Amphibian Fungal Pathogen, Batrachochytrium dendrobatidis, Based on IPCC Climate Futures.

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Gisselle Yang Xie

Full Text Available Projected changes in climate conditions are emerging as significant risk factors to numerous species, affecting habitat conditions and community interactions. Projections suggest species range shifts in response to climate change modifying environmental suitability and is supported by observational evidence. Both pathogens and their hosts can shift ranges with climate change. We consider how climate change may influence the distribution of the emerging infectious amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, a pathogen associated with worldwide amphibian population losses. Using an expanded global Bd database and a novel modeling approach, we examined a broad set of climate metrics to model the Bd-climate niche globally and regionally, then project how climate change may influence Bd distributions. Previous research showed that Bd distribution is dependent on climatic variables, in particular temperature. We trained a machine-learning model (random forest with the most comprehensive global compilation of Bd sampling records (~5,000 site-level records, mid-2014 summary, including 13 climatic variables. We projected future Bd environmental suitability under IPCC scenarios. The learning model was trained with combined worldwide data (non-region specific and also separately per region (region-specific. One goal of our study was to estimate of how Bd spatial risks may change under climate change based on the best available data. Our models supported differences in Bd-climate relationships among geographic regions. We projected that Bd ranges will shift into higher latitudes and altitudes due to increased environmental suitability in those regions under predicted climate change. Specifically, our model showed a broad expansion of areas environmentally suitable for establishment of Bd on amphibian hosts in the temperate zones of the Northern Hemisphere. Our projections are useful for the development of monitoring designs in these areas

Characterization of the Carbohydrate Binding Module 18 gene family in the amphibian pathogen Batrachochytrium dendrobatidis.

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Liu, Peng; Stajich, Jason E

2015-04-01

Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis responsible for worldwide decline in amphibian populations. Previous analysis of the Bd genome revealed a unique expansion of the carbohydrate-binding module family 18 (CBM18) predicted to be a sub-class of chitin recognition domains. CBM expansions have been linked to the evolution of pathogenicity in a variety of fungal species by protecting the fungus from the host. Based on phylogenetic analysis and presence of additional protein domains, the gene family can be classified into 3 classes: Tyrosinase-, Deacetylase-, and Lectin-like. Examination of the mRNA expression levels from sporangia and zoospores of nine of the cbm18 genes found that the Lectin-like genes had the highest expression while the Tyrosinase-like genes showed little expression, especially in zoospores. Heterologous expression of GFP-tagged copies of four CBM18 genes in Saccharomyces cerevisiae demonstrated that two copies containing secretion signal peptides are trafficked to the cell boundary. The Lectin-like genes cbm18-ll1 and cbm18-ll2 co-localized with the chitinous cell boundaries visualized by staining with calcofluor white. In vitro assays of the full length and single domain copies from CBM18-LL1 demonstrated chitin binding and no binding to cellulose or xylan. Expressed CBM18 domain proteins were demonstrated to protect the fungus, Trichoderma reeseii, in vitro against hydrolysis from exogenously added chitinase, likely by binding and limiting exposure of fungal chitin. These results demonstrate that cbm18 genes can play a role in fungal defense and expansion of their copy number may be an important pathogenicity factor of this emerging infectious disease of amphibians. Copyright © 2015 Elsevier Inc. All rights reserved.

Presence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) in rainwater suggests aerial dispersal is possible

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Kolby, Jonathan E.; Sara D. Ramirez,; Lee Berger,; Griffin, Dale W.; Merlijn Jocque,; Lee F. Skerratt,

2015-01-01

Abstract Global spread of the pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) may involve dispersal mechanisms not previously explored. Weather systems accompanied by strong wind and rainfall have been known to assist the dispersal of microbes pathogenic to plants and animals, and we considered a similar phenomenon might occur with Bd. We investigated this concept by sampling rainwater from 20 precipitation events for the presence of Bd in Cusuco National Park, Honduras: a site where high Bd prevalence was previously detected in stream-associated amphibians. Quantitative PCR analysis confirmed the presence of Bd in rainwater in one (5 %) of the weather events sampled, although viability cannot be ascertained from molecular presence alone. The source of the Bd and distance that the contaminated rainwater traveled could not be determined; however, this collection site was located approximately 600 m from the nearest observed perennial river by straight-line aerial distance. Although our results suggest atmospheric Bd dispersal is uncommon and unpredictable, even occasional short-distance aerial transport could considerably expand the taxonomic diversity of amphibians vulnerable to exposure and at risk of decline, including terrestrial and arboreal species that are not associated with permanent water bodies.

Correlates of virulence in a frog-killing fungal pathogen: evidence from a California amphibian decline

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Jonah Piovia-Scott; Karen Pope; S. Joy Worth; Erica Bree Rosenblum; Dean Simon; Gordon Warburton; Louise A. Rollins-Smith; Laura K. Reinert; Heather L. Wells; Dan Rejmanek; Sharon Lawler; Janet Foley

2015-01-01

The fungal pathogen Batrachochytrium dendrobatidis (Bd) has caused declines and extinctions in amphibians worldwide, and there is increasing evidence that some strains of this pathogen are more virulent than others. While a number of putative virulence factors have been identified, few studies link these factors to specific epizootic events. We...

Parallels in amphibian and bat declines from pathogenic fungi.

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Eskew, Evan A; Todd, Brian D

2013-03-01

Pathogenic fungi have substantial effects on global biodiversity, and 2 emerging pathogenic species-the chytridiomycete Batrachochytrium dendrobatidis, which causes chytridiomycosis in amphibians, and the ascomycete Geomyces destructans, which causes white-nose syndrome in hibernating bats-are implicated in the widespread decline of their vertebrate hosts. We synthesized current knowledge for chytridiomycosis and white-nose syndrome regarding disease emergence, environmental reservoirs, life history characteristics of the host, and host-pathogen interactions. We found striking similarities between these aspects of chytridiomycosis and white-nose syndrome, and the research that we review and propose should help guide management of future emerging fungal diseases.

Differential patterns of Batrachochytrium dendrobatidis infection in relict amphibian populations following severe disease-associated declines.

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Whitfield, Steven M; Alvarado, Gilbert; Abarca, Juan; Zumbado, Hector; Zuñiga, Ibrahim; Wainwright, Mark; Kerby, Jacob

2017-09-20

Global amphibian biodiversity has declined dramatically in the past 4 decades, and many amphibian species have declined to near extinction as a result of emergence of the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd). However, persistent or recovering populations of several amphibian species have recently been rediscovered, and such populations may illustrate how amphibian species that are highly susceptible to chytridiomycosis may survive in the presence of Bd. We conducted field surveys for Bd infection in 7 species of Costa Rican amphibians (all species that have declined to near extinction but for which isolated populations persist) to characterize infection profiles in highly Bd-susceptible amphibians post-decline. We found highly variable patterns in infection, with some species showing low prevalence (~10%) and low infection intensity and others showing high infection prevalence (>80%) and either low or high infection intensity. Across sites, infection rates were negatively associated with mean annual precipitation, and infection intensity across sites was negatively associated with mean average temperatures. Our results illustrate that even the most Bd-susceptible amphibians can persist in Bd-enzootic ecosystems, and that multiple ecological or evolutionary mechanisms likely exist for host-pathogen co-existence between Bd and the most Bd-susceptible amphibian species. Continued monitoring of these populations is necessary to evaluate population trends (continuing decline, stability, or population growth). These results should inform efforts to mitigate impacts of Bd on amphibians in the field.

Reduced itraconazole concentration and durations are successful in treating Batrachochytrium dendrobatidis infection in amphibians.

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Brannelly, Laura A

2014-03-14

Amphibians are experiencing the greatest decline of any vertebrate class and a leading cause of these declines is a fungal pathogen, Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis. Captive assurance colonies are important worldwide for threatened amphibian species and may be the only lifeline for those in critical threat of extinction. Maintaining disease free colonies is a priority of captive managers, yet safe and effective treatments for all species and across life stages have not been identified. The most widely used chemotherapeutic treatment is itraconazole, although the dosage commonly used can be harmful to some individuals and species. We performed a clinical treatment trial to assess whether a lower and safer but effective dose of itraconazole could be found to cure Bd infections. We found that by reducing the treatment concentration from 0.01-0.0025% and reducing the treatment duration from 11-6 days of 5 min baths, frogs could be cured of Bd infection with fewer side effects and less treatment-associated mortality.

Batrachochytrium dendrobatidis infection patterns among Panamanian amphibian species, habitats and elevations during epizootic and enzootic stages.

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Brem, Forrest M R; Lips, Karen R

2008-09-24

The pathogenic fungus Batrachochytrium dendrobatidis (Bd) has caused declines of many amphibian populations, yet the full course of the epizootic has rarely been observed in wild populations. We determined effects of elevation, habitat, and aquatic index (AI) on prevalence of infection among Panamanian amphibians sampled along 2 elevational transects. Amphibian populations on the Santa Fé transect (SFT) had declined in 2002, while those on the El Copé transect (ECT) were healthy until September 2004. In 2004 we sampled Bd along both transects, surveying the SFT 2 yr after decline, and surveying the ECT 4 mo prior to the arrival of Bd, during the epizootic, and 2 mo later. Overall prevalence of Bd along the ECT increased from 0.0 (95% CI 0.00-0.0003) to 0.51 (95% CI 0.48-0.55) over a 3 mo period, accompanied by significant decreases in amphibian abundance and species richness in all habitats. Prevalence of infection on the ECT was highest along riparian transects and at higher elevations, but not among levels of AI. Prevalence of infection on the SFT was highest in pool transects, and at higher elevations, but not among levels of AI. Riparian amphibian abundance and species richness also declined at SFT following detection of Bd in 2002. Variation among species, microenvironmental conditions, and the length of coexistence with Bd may contribute to observed differences in prevalence of Bd and in population response.

Do pathogens become more virulent as they spread? Evidence from the amphibian declines in Central America.

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Phillips, Ben L; Puschendorf, Robert

2013-09-07

The virulence of a pathogen can vary strongly through time. While cyclical variation in virulence is regularly observed, directional shifts in virulence are less commonly observed and are typically associated with decreasing virulence of biological control agents through coevolution. It is increasingly appreciated, however, that spatial effects can lead to evolutionary trajectories that differ from standard expectations. One such possibility is that, as a pathogen spreads through a naive host population, its virulence increases on the invasion front. In Central America, there is compelling evidence for the recent spread of pathogenic Batrachochytrium dendrobatidis (Bd) and for its strong impact on amphibian populations. Here, we re-examine data on Bd prevalence and amphibian population decline across 13 sites from southern Mexico through Central America, and show that, in the initial phases of the Bd invasion, amphibian population decline lagged approximately 9 years behind the arrival of the pathogen, but that this lag diminished markedly over time. In total, our analysis suggests an increase in Bd virulence as it spread southwards, a pattern consistent with rapid evolution of increased virulence on Bd's invading front. The impact of Bd on amphibians might therefore be driven by rapid evolution in addition to more proximate environmental drivers.

Estimating Herd Immunity to Amphibian Chytridiomycosis in Madagascar Based on the Defensive Function of Amphibian Skin Bacteria

OpenAIRE

Bletz, Molly C.; Myers, Jillian; Woodhams, Douglas C.; Rabemananjara, Falitiana C. E.; Rakotonirina, Angela; Weldon, Che; Edmonds, Devin; Vences, Miguel; Harris, Reid N.

2017-01-01

For decades, Amphibians have been globally threatened by the still expanding infectious disease, chytridiomycosis. Madagascar is an amphibian biodiversity hotspot where Batrachochytrium dendrobatidis (Bd) has only recently been detected. While no Bd-associated population declines have been reported, the risk of declines is high when invasive virulent lineages become involved. Cutaneous bacteria contribute to host innate immunity by providing defense against pathogens for numerous animals, inc...

Occurrence of Batrachochytrium dendrobatidis in an anuran community in the southeastern Talamanca Region of Costa Rica

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Daniel Saenz; Cory K. Adams; Josh B. Pierce; David Laurencio

2009-01-01

Soon after the discovery of the amphibian disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd, Longcore et al. 1999), it became apparent that Bd was a major threat to amphibians resulting in mass die-offs and population declines throughout the world (Berger et aI. 1998; Blaustein and Keisecker 2002; Daszak et aI. 2003; McCallum...

Amphibian commerce as a likely source of pathogen pollution.

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Picco, Angela M; Collins, James P

2008-12-01

The commercial trade of wildlife occurs on a global scale. In addition to removing animals from their native populations, this trade may lead to the release and subsequent introduction of nonindigenous species and the pathogens they carry. Emerging infectious diseases, such as chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), and ranaviral disease have spread with global trade in amphibians and are linked to amphibian declines and die-offs worldwide, which suggests that the commercial trade in amphibians may be a source of pathogen pollution. We screened tiger salamanders involved in the bait trade in the western United States for both ranaviruses and Bd with polymerase chain reaction and used oral reports from bait shops and ranavirus DNA sequences from infected bait salamanders to determine how these animals and their pathogens are moved geographically by commerce. In addition, we conducted 2 surveys of anglers to determine how often tiger salamanders are used as bait and how often they are released into fishing waters by anglers, and organized bait-shop surveys to determine whether tiger salamanders are released back into the wild after being housed in bait shops. Ranaviruses were detected in the tiger salamander bait trade in Arizona, Colorado, and New Mexico, and Bd was detected in Arizona bait shops. Ranaviruses were spread geographically through the bait trade. All tiger salamanders in the bait trade were collected from the wild, and in general they moved east to west and north to south, bringing with them their multiple ranavirus strains. Finally, 26-73% of anglers used tiger salamanders as fishing bait, 26-67% of anglers released tiger salamanders bought as bait into fishing waters, and 4% of bait shops released tiger salamanders back into the wild after they were housed in shops with infected animals. The tiger salamander bait trade in the western United States is a useful model for understanding the consequences of the

Unlocking the story in the swab: A new genotyping assay for the amphibian chytrid fungus Batrachochytrium dendrobatidis.

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Byrne, Allison Q; Rothstein, Andrew P; Poorten, Thomas J; Erens, Jesse; Settles, Matthew L; Rosenblum, Erica Bree

2017-11-01

One of the most devastating emerging pathogens of wildlife is the chytrid fungus, Batrachochytrium dendrobatidis (Bd), which affects hundreds of amphibian species around the world. Genomic data from pure Bd cultures have advanced our understanding of Bd phylogenetics, genomic architecture and mechanisms of virulence. However, pure cultures are laborious to obtain and whole-genome sequencing is comparatively expensive, so relatively few isolates have been genetically characterized. Thus, we still know little about the genetic diversity of Bd in natural systems. The most common noninvasive method of sampling Bd from natural populations is to swab amphibian skin. Hundreds of thousands of swabs have been collected from amphibians around the world, but Bd DNA collected via swabs is often low in quality and/or quantity. In this study, we developed a custom Bd genotyping assay using the Fluidigm Access Array platform to amplify 192 carefully selected regions of the Bd genome. We obtained robust sequence data for pure Bd cultures and field-collected skin swabs. This new assay has the power to accurately discriminate among the major Bd clades, recovering the basic tree topology previously revealed using whole-genome data. Additionally, we established a critical value for initial Bd load for swab samples (150 Bd genomic equivalents) above which our assay performs well. By leveraging advances in microfluidic multiplex PCR technology and the globally distributed resource of amphibian swab samples, noninvasive skin swabs can now be used to address critical spatial and temporal questions about Bd and its effects on declining amphibian populations. © 2017 John Wiley & Sons Ltd.

Unexpected rarity of the pathogen Batrachochytrium dendrobatidis in Appalachian Plethodon Salamanders: 1957-2011.

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Carly Muletz

Full Text Available Widespread population declines in terrestrial Plethodon salamanders occurred by the 1980s throughout the Appalachian Mountains, the center of global salamander diversity, with no evident recovery. We tested the hypothesis that the historic introduction and spread of the pathogenic fungus Batrachochytrium dendrobatidis (Bd into the eastern US was followed by Plethodon population declines. We expected to detect elevated prevalence of Bd prior to population declines as observed for Central American plethodontids. We tested 1,498 Plethodon salamanders of 12 species (892 museum specimens, 606 wild individuals for the presence of Bd, and tested 94 of those for Batrachochytrium salamandrivorans (Bs and for ranavirus. Field samples were collected in 2011 from 48 field sites across a 767 km transect. Historic samples from museum specimens were collected at five sites with the greatest number and longest duration of collection (1957-987, four of which were sampled in the field in 2011. None of the museum specimens were positive for Bd, but four P. cinereus from field surveys were positive. The overall Bd prevalence from 1957-2011 for 12 Plethodon species sampled across a 757 km transect was 0.2% (95% CI 0.1-0.7%. All 94 samples were negative for Bs and ranavirus. We conclude that known amphibian pathogens are unlikely causes for declines in these Plethodon populations. Furthermore, these exceptionally low levels of Bd, in a region known to harbor Bd, may indicate that Plethodon specific traits limit Bd infection.

Species-level correlates of susceptibility to the pathogenic amphibian fungus Batrachochytrium dendrobatidis in the United States

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Betsy A. Bancroft; Barbara A. Han; Catherine L. Searle; Lindsay M. Biga; Deanna H. Olson; Lee B. Kats; Joshua J. Lawler; Andrew R. Blaustein

2011-01-01

Disease is often implicated as a factor in population declines of wildlife and plants. Understanding the characteristics that may predispose a species to infection by a particular pathogen can help direct conservation efforts. Recent declines in amphibian populations world-wide are a major conservation issue and may be caused in part by a fungal pathogen, ...

Amphibian chytridiomycosis: a review with focus on fungus-host interactions.

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Van Rooij, Pascale; Martel, An; Haesebrouck, Freddy; Pasmans, Frank

2015-11-25

Amphibian declines and extinctions are emblematic for the current sixth mass extinction event. Infectious drivers of these declines include the recently emerged fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans (Chytridiomycota). The skin disease caused by these fungi is named chytridiomycosis and affects the vital function of amphibian skin. Not all amphibians respond equally to infection and host responses might range from resistant, over tolerant to susceptible. The clinical outcome of infection is highly dependent on the amphibian host, the fungal virulence and environmental determinants. B. dendrobatidis infects the skin of a large range of anurans, urodeles and caecilians, whereas to date the host range of B. salamandrivorans seems limited to urodeles. So far, the epidemic of B. dendrobatidis is mainly limited to Australian, neotropical, South European and West American amphibians, while for B. salamandrivorans it is limited to European salamanders. Other striking differences between both fungi include gross pathology and thermal preferences. With this review we aim to provide the reader with a state-of-the art of host-pathogen interactions for both fungi, in which new data pertaining to the interaction of B. dendrobatidis and B. salamandrivorans with the host's skin are integrated. Furthermore, we pinpoint areas in which more detailed studies are necessary or which have not received the attention they merit.

Potential influence of plant chemicals on infectivity of Batrachochytrium dendrobatidis.

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Davidson, Elizabeth W; Larsen, Andrew; Meins Palmer, Crystal

2012-11-08

We explored whether extracts of trees frequently found associated with amphibian habitats in Australia and Arizona, USA, may be inhibitory to the fungal pathogen Batrachochytrium dendrobatidis (Bd), which has been associated with global amphibian declines. We used salamanders Ambystoma tigrinum as the model system. Salamanders acquired significantly lower loads of Bd when exposed on leaves and extracts from the river red gum Eucalyptus camaldulensis, and loads were also low in some animals exposed on extracts of 2 oak species, Quercus emoryi and Q. turbinella. Some previously infected salamanders had their pathogen loads reduced, and some were fully cured, by placing them in leaf extracts, although some animals also self cured when housed in water alone. A significant number of animals cured of Bd infections 6 mo earlier were found to be resistant to reinfection. These results suggest that plants associated with amphibian habitats should be taken into consideration when explaining the prevalence of Bd in these habitats and that some amphibians may acquire resistance to the fungus if previously cured.

Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America.

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Tara Chestnut

Full Text Available Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd, is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L(-1. The highest density observed was ∼3 million zoospores L(-1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure to free

Whether the weather drives patterns of endemic amphibian chytridiomycosis: a pathogen proliferation approach.

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Kris A Murray

Full Text Available The pandemic amphibian disease chytridiomycosis often exhibits strong seasonality in both prevalence and disease-associated mortality once it becomes endemic. One hypothesis that could explain this temporal pattern is that simple weather-driven pathogen proliferation (population growth is a major driver of chytridiomycosis disease dynamics. Despite various elaborations of this hypothesis in the literature for explaining amphibian declines (e.g., the chytrid thermal-optimum hypothesis it has not been formally tested on infection patterns in the wild. In this study we developed a simple process-based model to simulate the growth of the pathogen Batrachochytrium dendrobatidis (Bd under varying weather conditions to provide an a priori test of a weather-linked pathogen proliferation hypothesis for endemic chytridiomycosis. We found strong support for several predictions of the proliferation hypothesis when applied to our model species, Litoria pearsoniana, sampled across multiple sites and years: the weather-driven simulations of pathogen growth potential (represented as a growth index in the 30 days prior to sampling; GI30 were positively related to both the prevalence and intensity of Bd infections, which were themselves strongly and positively correlated. In addition, a machine-learning classifier achieved ~72% success in classifying positive qPCR results when utilising just three informative predictors 1 GI30, 2 frog body size and 3 rain on the day of sampling. Hence, while intrinsic traits of the individuals sampled (species, size, sex and nuisance sampling variables (rainfall when sampling influenced infection patterns obtained when sampling via qPCR, our results also strongly suggest that weather-linked pathogen proliferation plays a key role in the infection dynamics of endemic chytridiomycosis in our study system. Predictive applications of the model include surveillance design, outbreak preparedness and response, climate change scenario

Whether the weather drives patterns of endemic amphibian chytridiomycosis: a pathogen proliferation approach.

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Murray, Kris A; Skerratt, Lee F; Garland, Stephen; Kriticos, Darren; McCallum, Hamish

2013-01-01

The pandemic amphibian disease chytridiomycosis often exhibits strong seasonality in both prevalence and disease-associated mortality once it becomes endemic. One hypothesis that could explain this temporal pattern is that simple weather-driven pathogen proliferation (population growth) is a major driver of chytridiomycosis disease dynamics. Despite various elaborations of this hypothesis in the literature for explaining amphibian declines (e.g., the chytrid thermal-optimum hypothesis) it has not been formally tested on infection patterns in the wild. In this study we developed a simple process-based model to simulate the growth of the pathogen Batrachochytrium dendrobatidis (Bd) under varying weather conditions to provide an a priori test of a weather-linked pathogen proliferation hypothesis for endemic chytridiomycosis. We found strong support for several predictions of the proliferation hypothesis when applied to our model species, Litoria pearsoniana, sampled across multiple sites and years: the weather-driven simulations of pathogen growth potential (represented as a growth index in the 30 days prior to sampling; GI30) were positively related to both the prevalence and intensity of Bd infections, which were themselves strongly and positively correlated. In addition, a machine-learning classifier achieved ~72% success in classifying positive qPCR results when utilising just three informative predictors 1) GI30, 2) frog body size and 3) rain on the day of sampling. Hence, while intrinsic traits of the individuals sampled (species, size, sex) and nuisance sampling variables (rainfall when sampling) influenced infection patterns obtained when sampling via qPCR, our results also strongly suggest that weather-linked pathogen proliferation plays a key role in the infection dynamics of endemic chytridiomycosis in our study system. Predictive applications of the model include surveillance design, outbreak preparedness and response, climate change scenario modelling and

Genetic evidence for a high diversity and wide distribution of endemic strains of the pathogenic chytrid fungus Batrachochytrium dendrobatidis in wild Asian amphibians.

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Bataille, Arnaud; Fong, Jonathan J; Cha, Moonsuk; Wogan, Guinevere O U; Baek, Hae Jun; Lee, Hang; Min, Mi-Sook; Waldman, Bruce

2013-08-01

Population declines and extinctions of amphibians have been attributed to the chytrid fungus Batrachochytrium dendrobatidis (Bd), especially one globally emerging recombinant lineage ('Bd-GPL'). We used PCR assays that target the ribosomal internal transcribed spacer region (ITS) of Bd to determine the prevalence and genetic diversity of Bd in South Korea, where Bd is widely distributed but is not known to cause morbidity or mortality in wild populations. We isolated Korean Bd strains from native amphibians with low infection loads and compared them to known worldwide Bd strains using 19 polymorphic SNP and microsatellite loci. Bd prevalence ranged between 12.5 and 48.0%, in 11 of 17 native Korean species, and 24.7% in the introduced bullfrog Lithobates catesbeianus. Based on ITS sequence variation, 47 of the 50 identified Korean haplotypes formed a group closely associated with a native Brazilian Bd lineage, separated from the Bd-GPL lineage. However, multilocus genotyping of three Korean Bd isolates revealed strong divergence from both Bd-GPL and the native Brazilian Bd lineages. Thus, the ITS region resolves genotypes that diverge from Bd-GPL but otherwise generates ambiguous phylogenies. Our results point to the presence of highly diversified endemic strains of Bd across Asian amphibian species. The rarity of Bd-GPL-associated haplotypes suggests that either this lineage was introduced into Korea only recently or Bd-GPL has been outcompeted by native Bd strains. Our results highlight the need to consider possible complex interactions among native Bd lineages, Bd-GPL and their associated amphibian hosts when assessing the spread and impact of Bd-GPL on worldwide amphibian populations. © 2013 John Wiley & Sons Ltd.

Low prevalence of chytrid fungus (Batrachochytrium dendrobatidis) in amphibians of U.S. headwater streams

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Hossack, Blake R.; Adams, Michael J.; Campbell Grant, Evan H.; Pearl, Chistopher A.; Bettaso, James B.; Barichivich, William J.; Lowe, Winsor H.; True, Kimberly; Ware, Joy L.; Corn, Paul Stephen

2010-01-01

Many declines of amphibian populations have been associated with chytridiomycosis, a disease caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd). Despite the relatively high prevalence of chytridiomycosis in stream amphibians globally, most surveys in North America have focused primarily on wetland-associated species, which are frequently infected. To better understand the distribution and prevalence of Bd in headwater amphibian communities, we sampled 452 tailed frogs (Ascaphus truei and Ascaphus montanus) and 304 stream salamanders (seven species in the Dicamptodontidae and Plethodontidae) for Bd in 38, first- to third-order streams in five montane areas across the United States. We tested for presence of Bd by using PCR on skin swabs from salamanders and metamorphosed tailed frogs or the oral disc of frog larvae. We detected Bd on only seven individuals (0.93%) in four streams. Based on our study and results from five other studies that have sampled headwater- or seep-associated amphibians in the United States, Bd has been detected on only 3% of 1,322 individuals from 21 species. These results differ strongly from surveys in Central America and Australia, where Bd is more prevalent on stream-breeding species, as well as results from wetland-associated anurans in the same regions of the United States that we sampled. Differences in the prevalence of Bd between stream- and wetland-associated amphibians in the United States may be related to species-specific variation in susceptibility to chytridiomycosis or habitat differences.

Fluorescent probes as a tool for labelling and tracking the amphibian chytrid fungus Batrachochytrium dendrobatidis.

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Herbert, Sarah M; Leung, Tommy L F; Bishop, Phillip J

2011-09-09

The dissemination of the virulent pathogen Batrachochytrium dendrobatidis (Bd) has contributed to the decline and extinction of many amphibian species worldwide. Several different strains have been identified, some of which are sympatric. Interactions between co-infecting strains of a pathogen can have significant influences on disease epidemiology and evolution; therefore the dynamics of multi-strain infections is an important area of research. We stained Bd cells with 2 fluorescent BODIPY fatty acid probes to determine whether these can potentially be used to distinguish and track Bd cell lines in multi-strain experiments. Bd cells in broth culture were stained with 5 concentrations of green-fluorescent BODIPY FL and red-fluorescent BODIPY 558/568 and visualised under an epifluorescent microscope for up to 16 d post-dye. Dyed strains were also assessed for growth inhibition. The most effective concentration for both dyes was 10 pM. This concentration of dye produced strong fluorescence for 12 to 16 d in Bd cultures held at 23 degrees C (3 to 4 generations), and did not inhibit Bd growth. Cells dyed with BODIPY FL and BODIPY 558/568 can be distinguished from each other on the basis of their fluorescence characteristics. Therefore, it is likely that this technique will be useful for research into multi-strain dynamics of Bd infections.

Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America

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Chestnut, Tara E.; Anderson, Chauncey; Popa, Radu; Blaustein, Andrew R.; Voytek, Mary; Olson, Deanna H.; Kirshtein, Julie

2014-01-01

Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd), is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L−1. The highest density observed was ∼3 million zoospores L−1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure

Epidemic disease decimates amphibian abundance, species diversity, and evolutionary history in the highlands of central Panama

OpenAIRE

Crawford, Andrew J.; Lips, Karen R.; Bermingham, Eldredge

2010-01-01

Amphibian populations around the world are experiencing unprecedented declines attributed to a chytrid fungal pathogen, Batrachochytrium dendrobatidis. Despite the severity of the crisis, quantitative analyses of the effects of the epidemic on amphibian abundance and diversity have been unavailable as a result of the lack of equivalent data collected before and following disease outbreak. We present a community-level assessment combining long-term field surveys and DNA barcode data describing...

Short-term exposure to warm microhabitats could explain amphibian persistence with Batrachochytrium dendrobatidis.

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Daskin, Joshua H; Alford, Ross A; Puschendorf, Robert

2011-01-01

Environmental conditions can alter the outcomes of symbiotic interactions. Many amphibian species have declined due to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), but many others persist despite high Bd infection prevalence. This indicates that Bd's virulence is lower, or it may even be a commensal, in some hosts. In the Australian Wet Tropics, chytridiomycosis extirpated Litoria nannotis from high-elevation rain forests in the early 1990 s. Although the species is recolonizing many sites, no population has fully recovered. Litoria lorica disappeared from all known sites in the early 1990 s and was thought globally extinct, but a new population was discovered in 2008, in an upland dry forest habitat it shares with L. nannotis. All frogs of both species observed during three population censuses were apparently healthy, but most carried Bd. Frogs perch on sun-warmed rocks in dry forest streams, possibly keeping Bd infections below the lethal threshold attained in cooler rain forests. We tested whether short-term elevated temperatures can hamper Bd growth in vitro over one generation (four days). Simulating the temperatures available to frogs on strongly and moderately warmed rocks in dry forests, by incubating cultures at 33°C for one hour daily, reduced Bd growth below that of Bd held at 15°C constantly (representing rain forest habitats). Even small decreases in the exponential growth rate of Bd on hosts may contribute to the survival of frogs in dry forests.

Short-term exposure to warm microhabitats could explain amphibian persistence with Batrachochytrium dendrobatidis.

Directory of Open Access Journals (Sweden)

Joshua H Daskin

Full Text Available Environmental conditions can alter the outcomes of symbiotic interactions. Many amphibian species have declined due to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd, but many others persist despite high Bd infection prevalence. This indicates that Bd's virulence is lower, or it may even be a commensal, in some hosts. In the Australian Wet Tropics, chytridiomycosis extirpated Litoria nannotis from high-elevation rain forests in the early 1990 s. Although the species is recolonizing many sites, no population has fully recovered. Litoria lorica disappeared from all known sites in the early 1990 s and was thought globally extinct, but a new population was discovered in 2008, in an upland dry forest habitat it shares with L. nannotis. All frogs of both species observed during three population censuses were apparently healthy, but most carried Bd. Frogs perch on sun-warmed rocks in dry forest streams, possibly keeping Bd infections below the lethal threshold attained in cooler rain forests. We tested whether short-term elevated temperatures can hamper Bd growth in vitro over one generation (four days. Simulating the temperatures available to frogs on strongly and moderately warmed rocks in dry forests, by incubating cultures at 33°C for one hour daily, reduced Bd growth below that of Bd held at 15°C constantly (representing rain forest habitats. Even small decreases in the exponential growth rate of Bd on hosts may contribute to the survival of frogs in dry forests.

Chironomidae bloodworms larvae as aquatic amphibian food.

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Fard, Mojdeh Sharifian; Pasmans, Frank; Adriaensen, Connie; Laing, Gijs Du; Janssens, Geert Paul Jules; Martel, An

2014-01-01

Different species of chironomids larvae (Diptera: Chironomidae) so-called bloodworms are widely distributed in the sediments of all types of freshwater habitats and considered as an important food source for amphibians. In our study, three species of Chironomidae (Baeotendipes noctivagus, Benthalia dissidens, and Chironomus riparius) were identified in 23 samples of larvae from Belgium, Poland, Russia, and Ukraine provided by a distributor in Belgium. We evaluated the suitability of these samples as amphibian food based on four different aspects: the likelihood of amphibian pathogens spreading, risk of heavy metal accumulation in amphibians, nutritive value, and risk of spreading of zoonotic bacteria (Salmonella, Campylobacter, and ESBL producing Enterobacteriaceae). We found neither zoonotic bacteria nor the amphibian pathogens Ranavirus and Batrachochytrium dendrobatidis in these samples. Our data showed that among the five heavy metals tested (Hg, Cu, Cd, Pb, and Zn), the excess level of Pb in two samples and low content of Zn in four samples implicated potential risk of Pb accumulation and Zn inadequacy. Proximate nutritional analysis revealed that, chironomidae larvae are consistently high in protein but more variable in lipid content. Accordingly, variations in the lipid: protein ratio can affect the amount and pathway of energy supply to the amphibians. Our study indicated although environmentally-collected chironomids larvae may not be vectors of specific pathogens, they can be associated with nutritional imbalances and may also result in Pb bioaccumulation and Zn inadequacy in amphibians. Chironomidae larvae may thus not be recommended as single diet item for amphibians. © 2014 Wiley Periodicals, Inc.

Correlates of virulence in a frog-killing fungal pathogen: evidence from a California amphibian decline.

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Piovia-Scott, Jonah; Pope, Karen; Worth, S Joy; Rosenblum, Erica Bree; Poorten, Thomas; Refsnider, Jeanine; Rollins-Smith, Louise A; Reinert, Laura K; Wells, Heather L; Rejmanek, Dan; Lawler, Sharon; Foley, Janet

2015-07-01

The fungal pathogen Batrachochytrium dendrobatidis (Bd) has caused declines and extinctions in amphibians worldwide, and there is increasing evidence that some strains of this pathogen are more virulent than others. While a number of putative virulence factors have been identified, few studies link these factors to specific epizootic events. We documented a dramatic decline in juvenile frogs in a Bd-infected population of Cascades frogs (Rana cascadae) in the mountains of northern California and used a laboratory experiment to show that Bd isolated in the midst of this decline induced higher mortality than Bd isolated from a more stable population of the same species of frog. This highly virulent Bd isolate was more toxic to immune cells and attained higher density in liquid culture than comparable isolates. Genomic analyses revealed that this isolate is nested within the global panzootic lineage and exhibited unusual genomic patterns, including increased copy numbers of many chromosomal segments. This study integrates data from multiple sources to suggest specific phenotypic and genomic characteristics of the pathogen that may be linked to disease-related declines.

Chytrid fungus acts as a generalist pathogen infecting species-rich amphibian families in Brazilian rainforests.

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Valencia-Aguilar, Anyelet; Ruano-Fajardo, Gustavo; Lambertini, Carolina; da Silva Leite, Domingos; Toledo, Luís Felipe; Mott, Tamí

2015-05-11

The fungus Batrachochytrium dendrobatidis (Bd) is among the main causes of declines in amphibian populations. This fungus is considered a generalist pathogen because it infects several species and spreads rapidly in the wild. To date, Bd has been detected in more than 100 anuran species in Brazil, mostly in the southern portion of the Atlantic forest. Here, we report survey data from some poorly explored regions; these data considerably extend current information on the distribution of Bd in the northern Atlantic forest region. In addition, we tested the hypothesis that Bd is a generalist pathogen in this biome. We also report the first positive record for Bd in an anuran caught in the wild in Amazonia. In total, we screened 90 individuals (from 27 species), of which 39 individuals (from 22 species) were Bd-positive. All samples collected in Bahia (2 individuals), Pernambuco (3 individuals), Pará (1 individual), and Minas Gerais (1 individual) showed positive results for Bd. We found a positive correlation between anuran richness per family and the number of infected species in the Atlantic forest, supporting previous observations that Bd lacks strong host specificity; of 38% of the anuran species in the Atlantic forest that were tested for Bd infection, 25% showed positive results. The results of our study exemplify the pandemic and widespread nature of Bd infection in amphibians.

Distribution limits of Batrachochytrium dendrobatidis: a case study in the Rocky Mountains, USA

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Hossack, Blake R.; Muths, Erin L.; Anderson, Chauncey W.; Kirshtein, Julie D.; Corn, P. Stephen

2009-01-01

Knowledge of the environmental constraints on a pathogen is critical to predicting its dynamics and effects on populations. Batrachochytrium dendrobatidis (Bd), an aquatic fungus that has been linked with widespread amphibian declines, is ubiquitous in the Rocky Mountains. As part of assessing the distribution limits of Bd in our study area, we sampled the water column and sediments for Bd zoospores in 30 high-elevation water bodies that lacked amphibians. All water bodies were in areas where Bd has been documented from neighboring, lower-elevation areas. We targeted areas lacking amphibians because existence of Bd independent of amphibians would have both ecologic and management implications. We did not detect Bd, which supports the hypothesis that it does not live independently of amphibians. However, assuming a detection sensitivity of 59.5% (based on sampling of water where amphibians tested positive for Bd), we only had 95% confidence of detecting Bd if it was in > or =16% of our sites. Further investigation into potential abiotic reservoirs is needed, but our results provide a strategic step in determining the distributional and environmental limitations of Bd in our study region.

Global amphibian declines: perspectives from the United States and beyond

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Densmore, Christine L.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

2011-01-01

Over recent decades, amphibians have experienced population declines, extirpations and species-level extinctions at an alarming rate. Numerous potential etiologies for amphibian declines have been postulated including climate and habitat degradation. Other potential anthropogenic causes including overexploitation and the frequent introductions of invasive predatory species have also been blamed for amphibian declines. Still other underlying factors may include infectious diseases caused by the chytrid fungus Batrachochytrium dendrobatidis, pathogenic viruses (Ranavirus), and other agents. It is nearly certain that more than one etiology is to blame for the majority of the global amphibian declines, and that these causal factors include some combination of climatological or physical habitat destabilization and infectious disease, most notably chytridiomycosis. Scientific research efforts are aimed at elucidating these etiologies on local, regional, and global scales that we might better understand and counteract the driving forces behind amphibian declines. Conservation efforts as outlined in the Amphibian Conservation Action Plan of 2005 are also being made to curtail losses and prevent further extinctions wherever possible.

Bd on the beach: high prevalence of Batrachochytrium dendrobatidis in the lowland forests of Gorgona Island (Colombia, South America).

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Flechas, Sandra Victoria; Sarmiento, Carolina; Amézquita, Adolfo

2012-09-01

The amphibian chytrid fungus, Batrachochytrium dendrobatidis, Bd, has been implicated in the decimation and extinction of many amphibian populations worldwide, especially at mid and high elevations. Recent studies have demonstrated the presence of the pathogen in the lowlands from Australia and Central America. We extend here its elevational range by demonstrating its presence at the sea level, in the lowland forests of Gorgona Island, off the Pacific coast of Colombia. We conducted two field surveys, separated by four years, and diagnosed Bd by performing polymerase chain reactions on swab samples from the skin of five amphibian species. All species, including the Critically Endangered Atelopus elegans, tested positive for the pathogen, with prevalences between 3.9 % in A. elegans (in 2010) and 52 % in Pristimantis achatinus. Clinical signs of chytridiomycosis were not detected in any species. To our knowledge, this is the first report of B. dendrobatidis in tropical lowlands at sea level, where temperatures may exceed optimal growth temperatures of this pathogen. This finding highlights the need to understand the mechanisms allowing the interaction between frogs and pathogen in lowland ecosystems.

Diversity of Andean amphibians of the Tamá National Natural Park in Colombia: a survey for the presence of Batrachochytrium dendrobatidis

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Acevedo, A.A.; Franco, R.; Carrero, D.A.

2016-07-01

Changes in diversity and possible decreases in populations of amphibians have not yet been determined in many areas in the Andes. This study aimed to develop an inventory of the biodiversity of amphibians in the Andean areas of the Tamá National Natural Park (Tamá NNP) and to evaluate the patterns of infection by Batrachochytrium dendrobatidis (Bd) in preserved and degraded areas. We performed samplings focused on three habitats (forest, open areas and streams) in four localities from 2,000 to 3,200 m in altitude. Fourteen species were recorded, 12 of which were positive for Bd. A total of 541 individuals were diagnosed and 100 were positive. Our analyses showed that preserved areas play an important role in keeping many individuals Bd–free as compared to those in degraded areas. This was the first study to evaluate diversity and infection by Bd in the northeast region of Colombia. Our findings may help improve our knowledge of the diversity of amphibian species in the area and facilitate the implementation of action plans to mitigate the causes associated with the decrease in amphibian populations. (Author)

Distribution and pathogenicity of Batrachochytrium dendrobatidis in boreal toads from the grand teton area of western wyoming

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Murphy, P.J.; St-Hilaire, S.; Bruer, S.; Corn, P.S.; Peterson, C.R.

2009-01-01

The pathogen Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis, has been linked to amphibian population declines and extinctions worldwide. Bd has been implicated in recent declines of boreal toads, Bufo boreas boreas, in Colorado but populations of boreal toads in western Wyoming have high prevalence of Bd without suffering catastrophic mortality. In a field and laboratory study, we investigated the prevalence of Bd in boreal toads from the Grand Teton ecosystem (GRTE) in Wyoming and tested the pathogenicity of Bd to these toads in several environments. The pathogen was present in breeding adults at all 10 sites sampled, with a mean prevalence of 67%. In an experiment with juvenile toadlets housed individually in wet environments, 106 zoospores of Bd isolated from GRTE caused lethal disease in all Wyoming and Colorado animals within 35 days. Survival time was longer in toadlets from Wyoming than Colorado and in toadlets spending more time in dry sites. In a second trial involving Colorado toadlets exposed to 35% fewer Bd zoospores, infection peaked and subsided over 68 days with no lethal chytridiomycosis in any treatment. However, compared with drier aquaria with dry refuges, Bd infection intensity was 41% higher in more humid aquaria and 81% higher without dry refuges available. Our findings suggest that although widely infected in nature, Wyoming toads may escape chytridiomycosis due to a slight advantage in innate resistance or because their native habitat hinders Bd growth or provides more opportunities to reduce pathogen loads behaviorally than in Colorado. ?? 2009 International Association for Ecology and Health.

Batrachochytrium salamandrivorans is the predominant chytrid fungus in Vietnamese salamanders

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Laking, Alexandra E.; Ngo, Hai Ngoc; Pasmans, Frank; Martel, An; Nguyen, Tao Thien

2017-01-01

The amphibian chytrid fungi, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), pose a major threat to amphibian biodiversity. Recent evidence suggests Southeast Asia as a potential cradle for both fungi, which likely resulted in widespread host-pathogen co-existence. We sampled 583 salamanders from 8 species across Vietnam in 55 locations for Bsal and Bd, determined scaled mass index as a proxy for fitness and collected environmental data. Bsal was found within 14 of the 55 habitats (2 of which it was detected in 2013), in 5 salamandrid species, with a prevalence of 2.92%. The globalized pandemic lineage of Bd was found within one pond on one species with a prevalence of 0.69%. Combined with a complete lack of correlation between infection and individual body condition and absence of indication of associated disease, this suggests low level pathogen endemism and Bsal and Bd co-existence with Vietnamese salamandrid populations. Bsal was more widespread than Bd, and occurs at temperatures higher than tolerated by the type strain, suggesting a wider thermal niche than currently known. Therefore, this study provides support for the hypothesis that these chytrid fungi may be endemic to Asia and that species within this region may act as a disease reservoir. PMID:28287614

Future potential distribution of the emerging amphibian chytrid fungus under anthropogenic climate change.

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Rödder, Dennis; Kielgast, Jos; Lötters, Stefan

2010-11-01

Anthropogenic climate change poses a major threat to global biodiversity with a potential to alter biological interactions at all spatial scales. Amphibians are the most threatened vertebrates and have been subject to increasing conservation attention over the past decade. A particular concern is the pandemic emergence of the parasitic chytrid fungus Batrachochytrium dendrobatidis, which has been identified as the cause of extremely rapid large-scale declines and species extinctions. Experimental and observational studies have demonstrated that the host-pathogen system is strongly influenced by climatic parameters and thereby potentially affected by climate change. Herein we project a species distribution model of the pathogen onto future climatic scenarios generated by the IPCC to examine their potential implications on the pandemic. Results suggest that predicted anthropogenic climate change may reduce the geographic range of B. dendrobatidis and its potential influence on amphibian biodiversity.

Elevated Corticosterone Levels and Changes in Amphibian Behavior Are Associated with Batrachochytrium dendrobatidis (Bd Infection and Bd Lineage.

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Caitlin R Gabor

Full Text Available Few studies have examined the role hormones play in mediating clinical changes associated with infection by the parasite Batrachochytrium dendrobatidis (Bd. Glucocorticoid (GC hormones such as corticosteroids (CORT regulate homeostasis and likely play a key role in response to infection in amphibians. We explore the relationship between CORT release rates and Bd infection in tadpoles of the common midwife toad, Alytes obstetricians, using a non-invasive water-borne hormone collection method across seven populations. We further examined whether tadpoles of A. muletensis infected with a hypervirulent lineage of Bd, BdGPL, had greater CORT release rates than those infected with a hypovirulent lineage, BdCAPE. Finally, we examined the relationship between righting reflex and CORT release rates in infected metamorphic toads of A. obstetricans. We found an interaction between elevation and Bd infection status confirming that altitude is associated with the overall severity of infection. In tandem, increasing elevation was associated with increasing CORT release rates. Tadpoles infected with the hypervirulent BdGPL had significantly higher CORT release rates than tadpoles infected with BdCAPE showing that more aggressive infections lead to increased CORT release rates. Infected metamorphs with higher CORT levels had an impaired righting reflex, our defined experimental endpoint. These results provide evidence that CORT is associated with an amphibian's vulnerability to Bd infection, and that CORT is also affected by the aggressiveness of infection by Bd. Together these results indicate that CORT is a viable biomarker of amphibian stress.

Distribution and risk factors for spread of amphibian chytrid fungus Batrachochytrium dendrobatidis in the Tasmanian Wilderness World Heritage Area, Australia.

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Pauza, Matthew D; Driessen, Michael M; Skerratt, Lee F

2010-11-01

Chytridiomycosis is an emerging infectious disease caused by the pathogen Batrachochytrium dendrobatidis (Bd) and is the cause of the decline and extinction of amphibian species throughout the world. We surveyed the distribution of Bd within and around the Tasmanian Wilderness World Heritage Area (TWWHA), a 1.38 million ha area of significant fauna conservation value, which provides the majority of habitat for Tasmania's 3 endemic frog species (Litoria burrowsae, Bryobatrachus nimbus and Crinia tasmaniensis). Bd was detected at only 1 (3%) of the 33 sites surveyed within the TWWHA and at 15 (52%) of the 29 sites surveyed surrounding the TWWHA. The relatively low incidence of the disease within the TWWHA suggests that the majority of the TWWHA is currently free of the pathogen despite the fact that the region provides what appears to be optimal conditions for the persistence of Bd. For all survey sites within and around the TWWHA, the presence of Bd was strongly associated with the presence of gravel roads, forest and < 1000 m altitude--factors that in this study were associated with human-disturbed landscapes around the TWWHA. Conversely, the presence of walking tracks was strongly associated with the absence of Bd, suggesting an association of absence with relatively remote locations. The wide distribution of Bd in areas of Tasmania with high levels of human disturbance and its very limited occurrence in remote wilderness areas suggests that anthropogenic activities may facilitate the dissemination of the pathogen on a landscape scale in Tasmania. Because the majority of the TWWHA is not readily accessible and appears to be largely free of Bd, and because Tasmanian frogs reproduce in ponds rather than streams, it may be feasible to control the spread of the disease in the TWWHA.

Selecting for extinction: nonrandom disease-associated extinction homogenizes amphibian biotas.

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Smith, Kevin G; Lips, Karen R; Chase, Jonathan M

2009-10-01

Studying the patterns in which local extinctions occur is critical to understanding how extinctions affect biodiversity at local, regional and global spatial scales. To understand the importance of patterns of extinction at a regional spatial scale, we use data from extirpations associated with a widespread pathogenic agent of amphibian decline, Batrachochytrium dendrobatidis (Bd) as a model system. We apply novel null model analyses to these data to determine whether recent extirpations associated with Bd have resulted in selective extinction and homogenization of diverse tropical American amphibian biotas. We find that Bd-associated extinctions in this region were nonrandom and disproportionately, but not exclusively, affected low-occupancy and endemic species, resulting in homogenization of the remnant amphibian fauna. The pattern of extirpations also resulted in phylogenetic homogenization at the family level and ecological homogenization of reproductive mode and habitat association. Additionally, many more species were extirpated from the region than would be expected if extirpations occurred randomly. Our results indicate that amphibian declines in this region are an extinction filter, reducing regional amphibian biodiversity to highly similar relict assemblages and ultimately causing amplified biodiversity loss at regional and global scales.

Batrachochytrium dendrobatidis not found in rainforest frogs along an altitudinal gradient of Papua New Guinea

Czech Academy of Sciences Publication Activity Database

Dahl, C.; Kiatik, I.; Baisen, I.; Bronikowski, E.; Fleischer, R. C.; Rotzel, N. C.; Lock, J.; Novotný, Vojtěch; Narayan, E.; Hero, J.-M.

2012-01-01

Roč. 22, č. 3 (2012), s. 183-186 ISSN 0268-0130 Institutional support: RVO:60077344 Keywords : altitude * amphibians * Batrachochytrium dendrobatidis Subject RIV: EH - Ecology, Behaviour Impact factor: 1.081, year: 2012

Dr Jekyll and Mrs Hyde: Risky hybrid sex by amphibian-parasitizing chytrids in the Brazilian Atlantic Forests.

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Ghosh, Pria; Fisher, Matthew C

2016-07-01

In their article in this issue of Molecular Ecology, Jenkinson et al. () and colleagues address a worrying question-how could arguably the most dangerous pathogen known to science, Batrachochytrium dendrobatidis (Bd), become even more virulent? The answer: start having sex. Jenkinson et al. present a case for how the introduction into Brazil of the globally invasive lineage of Bd, BdGPL, has disrupted the relationship between native amphibians and an endemic Bd lineage, BdBrazil. BdBrazil is hypothesized to be native to the Atlantic Forest and so have a long co-evolutionary history with biodiverse Atlantic Forest amphibian community. The authors suggest that this has resulted in a zone of hybrid Bd genotypes which are potentially more likely to cause fatal chytridiomycosis than either parent lineage. The endemic-nonendemic Bd hybrid genotypes described in this study, and the evidence for pathogen translocation via the global amphibian trade presented, highlights the danger of anthropogenic pathogen dispersal. This research emphasizes that biosecurity regulations may have to refocus on lineages within species if we are to mitigate against the danger of new, possibly hypervirulent genotypes of pathogens emerging as phylogeographic barriers are breached. © 2016 John Wiley & Sons Ltd.

Prevalence of Batrachochytrium dendrobatidis in a Nicaraguan, micro-endemic Neotropical salamander, Bolitoglossa mombachoensis

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Stark, Tariq; Laurijssens, Carlijn; Weterings, Martijn; Martel, An; Köhler, Gunther; Pasmans, Frank

2017-01-01

Amphibians are the most threatened terrestrial vertebrates on the planet and are iconic in the global biodiversity crisis. Their global decline caused by the fungal agent Batrachochytrium dendrobatidis (Bd) is well known. Declines of Mesoamerican salamanders of the family Plethodontidae, mainly

Amphibian decline and extinction: what we know and what we need to learn.

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Collins, James P

2010-11-01

For over 350 million yr, thousands of amphibian species have lived on Earth. Since the 1980s, amphibians have been disappearing at an alarming rate, in many cases quite suddenly. What is causing these declines and extinctions? In the modern era (post 1500) there are 6 leading causes of biodiversity loss in general, and all of these acting alone or together are responsible for modern amphibian declines: commercial use; introduced/exotic species that compete with, prey on, and parasitize native frogs and salamanders; land use change; contaminants; climate change; and infectious disease. The first 3 causes are historical in the sense that they have been operating for hundreds of years, although the rate of change due to each accelerated greatly after about the mid-20th century. Contaminants, climate change, and emerging infectious diseases are modern causes suspected of being responsible for the so-called 'enigmatic decline' of amphibians in protected areas. Introduced/exotic pathogens, land use change, and infectious disease are the 3 causes with a clear role in amphibian decline as well as extinction; thus far, the other 3 causes are only implicated in decline and not extinction. The present work is a review of the 6 causes with a focus on pathogens and suggested areas where new research is needed. Batrachochytrium dendrobatidis (Bd) is a chytrid fungus that is an emerging infectious disease causing amphibian population decline and species extinction. Historically, pathogens have not been seen as a major cause of extinction, but Bd is an exception, which is why it is such an interesting, important pathogen to understand. The late 20th and early 21st century global biodiversity loss is characterized as a sixth extinction event. Amphibians are a striking example of these losses as they disappear at a rate that greatly exceeds historical levels. Consequently, modern amphibian decline and extinction is a lens through which we can view the larger story of biodiversity

Epidemic disease decimates amphibian abundance, species diversity, and evolutionary history in the highlands of central Panama.

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Crawford, Andrew J; Lips, Karen R; Bermingham, Eldredge

2010-08-03

Amphibian populations around the world are experiencing unprecedented declines attributed to a chytrid fungal pathogen, Batrachochytrium dendrobatidis. Despite the severity of the crisis, quantitative analyses of the effects of the epidemic on amphibian abundance and diversity have been unavailable as a result of the lack of equivalent data collected before and following disease outbreak. We present a community-level assessment combining long-term field surveys and DNA barcode data describing changes in abundance and evolutionary diversity within the amphibian community of El Copé, Panama, following a disease epidemic and mass-mortality event. The epidemic reduced taxonomic, lineage, and phylogenetic diversity similarly. We discovered that 30 species were lost, including five undescribed species, representing 41% of total amphibian lineage diversity in El Copé. These extirpations represented 33% of the evolutionary history of amphibians within the community, and variation in the degree of population loss and decline among species was random with respect to the community phylogeny. Our approach provides a fast, economical, and informative analysis of loss in a community whether measured by species or phylogenetic diversity.

Widespread occurrence of Batrachochytrium dendrobatidis in contemporary and historical samples of the endangered Bombina pachypus along the Italian peninsula.

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Daniele Canestrelli

Full Text Available Batrachochytrium dendrobatidis is considered a main driver of the worldwide declines and extinctions of amphibian populations. Nonetheless, fundamental questions about its epidemiology, including whether it acts mainly as a "lone killer" or in conjunction with other factors, remain largely open. In this paper we analysed contemporary and historical samples of the endangered Apennine yellow-bellied toad (Bombina pachypus along the Italian peninsula, in order to assess the presence of the pathogen and its spreading dynamics. Once common throughout its range, B. pachypus started to decline after the mid-1990s in the northern and central regions, whereas no declines have been observed so far in the southern region. We show that Batrachochytrium dendrobatidis is currently widespread along the entire peninsula, and that this was already so at least as early as the late 1970s, that is, well before the beginning of the observed declines. This temporal mismatch between pathogen occurrence and host decline, as well as the spatial pattern of the declines, suggests that the pathogen has not acted as a "lone killer", but in conjunction with other factors. Among the potentially interacting factors, we identified two as the most probable, genetic diversity of host populations and recent climate changes. We discuss the plausibility of this scenario and its implications on the conservation of B. pachypus populations.

Chytridiomycosis: a global threat to amphibians.

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Pereira, P L L; Torres, A M C; Soares, D F M; Hijosa-Valsero, M; Bécares, E

2013-12-01

Chytridiomycosis, which is caused by Batrachochytrium dendrobatidis, is an emerging infectious disease of amphibians. The disease is one of the main causes of the global decline in amphibians. The aetiological agent is ubiquitous, with worldwide distribution, and affects a large number of amphibian species in several biomes. In the last decade, scientific research has substantially increased knowledge of the aetiological agent and the associated infection. However, important epidemiological aspects of the environment-mediated interactions between the aetiological agent and the host are not yet clear. The objective of the present review is to describe chytridiomycosis with regard to the major features of the aetiological agent, the host and the environment.

Survey of Pathogenic Chytrid Fungi (Batrachochytrium dendrobatidis and B. salamandrivorans) in Salamanders from Three Mountain Ranges in Europe and the Americas.

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Parrott, Joshua Curtis; Shepack, Alexander; Burkart, David; LaBumbard, Brandon; Scimè, Patrick; Baruch, Ethan; Catenazzi, Alessandro

2017-06-01

Batrachochytrium salamandrivorans (Bsal) is a virulent fungal pathogen that infects salamanders. It is implicated in the recent collapse of several populations of fire salamanders in Europe. This pathogen seems much like that of its sister species, Batrachochytrium dendrobatidis (Bd), the agent responsible for anuran extinctions and extirpations worldwide, and is considered to be an emerging global threat to salamander communities. Bsal thrives at temperatures found in many mountainous regions rich in salamander species; because of this, we have screened specimens of salamanders representing 17 species inhabiting mountain ranges in three continents: The Smoky Mountains, the Swiss Alps, and the Peruvian Andes. We screened 509 salamanders, with 192 representing New World salamanders that were never tested for Bsal previously. Bsal was not detected, and Bd was mostly present at low prevalence except for one site in the Andes.

Linking ecology and epidemiology to understand predictors of multi-host responses to an emerging pathogen, the amphibian chytrid fungus

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Stephanie S. Gervasi; Patrick R. Stephens; Jessica Hua; Catherine L. Searle; Gisselle Yang Xie; Jenny Urbina; Deanna H. Olson; Betsy A. Bancroft; Virginia Weis; John I. Hammond; Rick A. Relyea; Andrew R. Blaustein; Stefan Lötters

2017-01-01

Variation in host responses to pathogens can have cascading effects on populations and communities when some individuals or groups of individuals display disproportionate vulnerability to infection or differ in their competence to transmit infection. The fungal pathogen, Batrachochytrium dendrobatidis (Bd) has been detected in almost 700 different...

Reservoir-host amplification of disease impact in an endangered amphibian.

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Scheele, Ben C; Hunter, David A; Brannelly, Laura A; Skerratt, Lee F; Driscoll, Don A

2017-06-01

Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd; some species tolerate infection, whereas others experience rapid mortality. Reservoir hosts-species that carry infection while maintaining high abundance but are rarely killed by disease-can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We investigated the role of reservoir hosts in the decline of the threatened northern corroboree frog (Pseudophryne pengilleyi) in an amphibian community in southeastern Australia. In the laboratory, we characterized the response of a potential reservoir host, the (nondeclining) common eastern froglet (Crinia signifera), to Bd infection. In the field, we conducted frog abundance surveys and Bd sampling for both P. pengilleyi and C. signifera. We built multinomial logistic regression models to test whether Crinia signifera and environmental factors were associated with P. pengilleyi decline. C. signifera was a reservoir host for Bd. In the laboratory, many individuals maintained intense infections (>1000 zoospore equivalents) over 12 weeks without mortality, and 79% of individuals sampled in the wild also carried infections. The presence of C. signifera at a site was strongly associated with increased Bd prevalence in sympatric P. pengilleyi. Consistent with disease amplification by a reservoir host, P. pengilleyi declined at sites with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines of susceptible species may continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined

Evidence for acquisition of virulence effectors in pathogenic chytrids

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Summers Kyle

2011-07-01

Full Text Available Abstract Background The decline in amphibian populations across the world is frequently linked to the infection of the chytrid fungus Batrachochytrium dendrobatidis (Bd. This is particularly perplexing because Bd was only recently discovered in 1999 and no chytrid fungus had previously been identified as a vertebrate pathogen. Results In this study, we show that two large families of known virulence effector genes, crinkler (CRN proteins and serine peptidases, were acquired by Bd from oomycete pathogens and bacteria, respectively. These two families have been duplicated after their acquisition by Bd. Additional selection analyses indicate that both families evolved under strong positive selection, suggesting that they are involved in the adaptation of Bd to its hosts. Conclusions We propose that the acquisition of virulence effectors, in combination with habitat disruption and climate change, may have driven the Bd epidemics and the decline in amphibian populations. This finding provides a starting point for biochemical investigations of chytridiomycosis.

Fight Fungi with Fungi: Antifungal Properties of the Amphibian Mycobiome

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Patrick J. Kearns

2017-12-01

Full Text Available Emerging infectious diseases caused by fungal taxa are increasing and are placing a substantial burden on economies and ecosystems worldwide. Of the emerging fungal diseases, chytridomycosis caused by the fungus Batrachochytrium dendrobatidis (hereafter Bd is linked to global amphibian declines. Amphibians have innate immunity, as well as additional resistance through cutaneous microbial communities. Despite the targeting of bacteria as potential probiotics, the role of fungi in the protection against Bd infection in unknown. We used a four-part approach, including high-throughput sequencing of bacterial and fungal communities, cultivation of fungi, Bd challenge assays, and experimental additions of probiotic to Midwife Toads (Altyes obstetricans, to examine the overlapping roles of bacterial and fungal microbiota in pathogen defense in captive bred poison arrow frogs (Dendrobates sp.. Our results revealed that cutaneous fungal taxa differed from environmental microbiota across three species and a subspecies of Dendrobates spp. frogs. Cultivation of host-associated and environmental fungi realved numerous taxa with the ability to inhibit or facilitate the growth of Bd. The abundance of cutaneous fungi contributed more to Bd defense (~45% of the fungal community, than did bacteria (~10% and frog species harbored distinct inhibitory communities that were distinct from the environment. Further, we demonstrated that a fungal probiotic therapy did not induce an endocrine-immune reaction, in contrast to bacterial probiotics that stressed amphibian hosts and suppressed antimicrobial peptide responses, limiting their long-term colonization potential. Our results suggest that probiotic strategies against amphibian fungal pathogens should, in addition to bacterial probiotics, focus on host-associated and environmental fungi such as Penicillium and members of the families Chaetomiaceae and Lasiosphaeriaceae.

Riding the wave: reconciling the roles of disease and climate change in amphibian declines.

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Karen R Lips

2008-03-01

Full Text Available We review the evidence for the role of climate change in triggering disease outbreaks of chytridiomycosis, an emerging infectious disease of amphibians. Both climatic anomalies and disease-related extirpations are recent phenomena, and effects of both are especially noticeable at high elevations in tropical areas, making it difficult to determine whether they are operating separately or synergistically. We compiled reports of amphibian declines from Lower Central America and Andean South America to create maps and statistical models to test our hypothesis of spatiotemporal spread of the pathogen Batrachochytrium dendrobatidis (Bd, and to update the elevational patterns of decline in frogs belonging to the genus Atelopus. We evaluated claims of climate change influencing the spread of Bd by including error into estimates of the relationship between air temperature and last year observed. Available data support the hypothesis of multiple introductions of this invasive pathogen into South America and subsequent spread along the primary Andean cordilleras. Additional analyses found no evidence to support the hypothesis that climate change has been driving outbreaks of amphibian chytridiomycosis, as has been posited in the climate-linked epidemic hypothesis. Future studies should increase retrospective surveys of museum specimens from throughout the Andes and should study the landscape genetics of Bd to map fine-scale patterns of geographic spread to identify transmission routes and processes.

Riding the wave: reconciling the roles of disease and climate change in amphibian declines.

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Lips, Karen R; Diffendorfer, Jay; Mendelson, Joseph R; Sears, Michael W

2008-03-25

We review the evidence for the role of climate change in triggering disease outbreaks of chytridiomycosis, an emerging infectious disease of amphibians. Both climatic anomalies and disease-related extirpations are recent phenomena, and effects of both are especially noticeable at high elevations in tropical areas, making it difficult to determine whether they are operating separately or synergistically. We compiled reports of amphibian declines from Lower Central America and Andean South America to create maps and statistical models to test our hypothesis of spatiotemporal spread of the pathogen Batrachochytrium dendrobatidis (Bd), and to update the elevational patterns of decline in frogs belonging to the genus Atelopus. We evaluated claims of climate change influencing the spread of Bd by including error into estimates of the relationship between air temperature and last year observed. Available data support the hypothesis of multiple introductions of this invasive pathogen into South America and subsequent spread along the primary Andean cordilleras. Additional analyses found no evidence to support the hypothesis that climate change has been driving outbreaks of amphibian chytridiomycosis, as has been posited in the climate-linked epidemic hypothesis. Future studies should increase retrospective surveys of museum specimens from throughout the Andes and should study the landscape genetics of Bd to map fine-scale patterns of geographic spread to identify transmission routes and processes.

There is no evidence for a temporal link between pathogen arrival and frog extinctions in north-eastern Australia.

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Ben L Phillips

Full Text Available Pathogen spread can cause population declines and even species extinctions. Nonetheless, in the absence of tailored monitoring schemes, documenting pathogen spread can be difficult. In the case of worldwide amphibian declines the best present understanding is that the chytrid fungus Batrachochytrium dendrobatidis (Bd has recently spread, causing amphibian declines and extinction in the process. However, good evidence demonstrating pathogen arrival followed by amphibian decline is rare, and analysis of putative evidence is often inadequate. Here we attempt to examine the relationship between Bd arrival and amphibian decline across north-eastern Australia, using sites where a wave-like pattern of amphibian decline was first noticed and at which intensive research has since been conducted. We develop an analytical framework that allows rigorous estimation of pathogen arrival date, which can then be used to test for a correlation between the time of pathogen arrival and amphibian decline across sites. Our results show that, with the current dataset, the earliest possible arrival date of Bd in north-eastern Australia is completely unresolved; Bd could have arrived immediately before sampling commenced or may have arrived thousands of years earlier, the present data simply cannot say. The currently available data are thus insufficient to assess the link between timing of pathogen arrival and population decline in this part of the world. This data insufficiency is surprising given that there have been decades of research on chytridiomycosis in Australia and that there is a general belief that the link between Bd arrival and population decline is well resolved in this region. The lack of data on Bd arrival currently acts as a major impediment to determining the role of environmental factors in driving the global amphibian declines, and should be a major focus of future research.

Estimating Herd Immunity to Amphibian Chytridiomycosis in Madagascar Based on the Defensive Function of Amphibian Skin Bacteria

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Molly C. Bletz

2017-09-01

Full Text Available For decades, Amphibians have been globally threatened by the still expanding infectious disease, chytridiomycosis. Madagascar is an amphibian biodiversity hotspot where Batrachochytrium dendrobatidis (Bd has only recently been detected. While no Bd-associated population declines have been reported, the risk of declines is high when invasive virulent lineages become involved. Cutaneous bacteria contribute to host innate immunity by providing defense against pathogens for numerous animals, including amphibians. Little is known, however, about the cutaneous bacterial residents of Malagasy amphibians and the functional capacity they have against Bd. We cultured 3179 skin bacterial isolates from over 90 frog species across Madagascar, identified them via Sanger sequencing of approximately 700 bp of the 16S rRNA gene, and characterized their functional capacity against Bd. A subset of isolates was also tested against multiple Bd genotypes. In addition, we applied the concept of herd immunity to estimate Bd-associated risk for amphibian communities across Madagascar based on bacterial antifungal activity. We found that multiple bacterial isolates (39% of all isolates cultured from the skin of Malagasy frogs were able to inhibit Bd. Mean inhibition was weakly correlated with bacterial phylogeny, and certain taxonomic groups appear to have a high proportion of inhibitory isolates, such as the Enterobacteriaceae, Pseudomonadaceae, and Xanthamonadaceae (84, 80, and 75% respectively. Functional capacity of bacteria against Bd varied among Bd genotypes; however, there were some bacteria that showed broad spectrum inhibition against all tested Bd genotypes, suggesting that these bacteria would be good candidates for probiotic therapies. We estimated Bd-associated risk for sampled amphibian communities based on the concept of herd immunity. Multiple amphibian communities, including those in the amphibian diversity hotspots, Andasibe and Ranomafana, were

Estimating Herd Immunity to Amphibian Chytridiomycosis in Madagascar Based on the Defensive Function of Amphibian Skin Bacteria.

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Bletz, Molly C; Myers, Jillian; Woodhams, Douglas C; Rabemananjara, Falitiana C E; Rakotonirina, Angela; Weldon, Che; Edmonds, Devin; Vences, Miguel; Harris, Reid N

2017-01-01

For decades, Amphibians have been globally threatened by the still expanding infectious disease, chytridiomycosis. Madagascar is an amphibian biodiversity hotspot where Batrachochytrium dendrobatidis ( Bd ) has only recently been detected. While no Bd -associated population declines have been reported, the risk of declines is high when invasive virulent lineages become involved. Cutaneous bacteria contribute to host innate immunity by providing defense against pathogens for numerous animals, including amphibians. Little is known, however, about the cutaneous bacterial residents of Malagasy amphibians and the functional capacity they have against Bd . We cultured 3179 skin bacterial isolates from over 90 frog species across Madagascar, identified them via Sanger sequencing of approximately 700 bp of the 16S rRNA gene, and characterized their functional capacity against Bd . A subset of isolates was also tested against multiple Bd genotypes. In addition, we applied the concept of herd immunity to estimate Bd -associated risk for amphibian communities across Madagascar based on bacterial antifungal activity. We found that multiple bacterial isolates (39% of all isolates) cultured from the skin of Malagasy frogs were able to inhibit Bd . Mean inhibition was weakly correlated with bacterial phylogeny, and certain taxonomic groups appear to have a high proportion of inhibitory isolates, such as the Enterobacteriaceae, Pseudomonadaceae, and Xanthamonadaceae (84, 80, and 75% respectively). Functional capacity of bacteria against Bd varied among Bd genotypes; however, there were some bacteria that showed broad spectrum inhibition against all tested Bd genotypes, suggesting that these bacteria would be good candidates for probiotic therapies. We estimated Bd -associated risk for sampled amphibian communities based on the concept of herd immunity. Multiple amphibian communities, including those in the amphibian diversity hotspots, Andasibe and Ranomafana, were estimated to be

Synergism between UV-B radiation and pathogen magnifies amphibian embryo mortality in nature

International Nuclear Information System (INIS)

Kiesecker, J.M.; Blaustein, R.

1995-01-01

Previous research has shown that amphibians have differential sensitivity to ultraviolet-B (UV-B) radiation. In some species, ambient levels of UV-B radiation cause embryonic mortality in nature. The detrimental effects of UV-B alone or with other agents may ultimately affect amphibians at the population level. Here, we experimentally demonstrate a synergistic effect between UV-B radiation and a pathogenic fungus in the field that increases the mortality of amphibian embryos compared with either factor alone. Studies investigating single factors for causes of amphibian egg mortality or population declines may not reveal the complex factors involved in declines

Early action to address an emerging wildlife disease

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Adams, Michael J.; Harris, M. Camille; Grear, Daniel A.

2017-02-23

A deadly fungal pathogen, Batrachochytrium salamandrivorans (Bsal) that affects amphibian skin was discovered during a die-off of European fire salamanders (Salamandra salamandra) in 2014. This pathogen has the potential to worsen already severe worldwide amphibian declines. Bsal is a close relative to another fungal disease known as Batrachochytrium dendrobatidis (Bd). Many scientists consider Bd to be the greatest threat to amphibian biodiversity of any disease because it affects a large number of species and has the unusual ability to drive species and populations to extinction.Although not yet detected in the United States, the emergence of Bsal could threaten the salamander population, which is the most diverse in the world. The spread of Bsal likely will lead to more State and federally listed threatened or endangered amphibian species, and associated economic effects.Because of the concern expressed by resource management agencies, the U.S. Geological Survey (USGS) has made Bsal and similar pathogens a priority for research.

Unlikely remedy: fungicide clears infection from pathogenic fungus in larval southern leopard frogs (Lithobates sphenocephalus.

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Shane M Hanlon

Full Text Available Amphibians are often exposed to a wide variety of perturbations. Two of these, pesticides and pathogens, are linked to declines in both amphibian health and population viability. Many studies have examined the separate effects of such perturbations; however, few have examined the effects of simultaneous exposure of both to amphibians. In this study, we exposed larval southern leopard frog tadpoles (Lithobates sphenocephalus to the chytrid fungus Batrachochytrium dendrobatidis and the fungicide thiophanate-methyl (TM at 0.6 mg/L under laboratory conditions. The experiment was continued until all larvae completed metamorphosis or died. Overall, TM facilitated increases in tadpole mass and length. Additionally, individuals exposed to both TM and Bd were heavier and larger, compared to all other treatments. TM also cleared Bd in infected larvae. We conclude that TM affects larval anurans to facilitate growth and development while clearing Bd infection. Our findings highlight the need for more research into multiple perturbations, specifically pesticides and disease, to further promote amphibian heath.

Occurrence of Batrachochytrium dendrobatidis in anurans of the Mediterranean region of Baja California, México

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Peralta-Garcia, Anny; Adams, Andrea J.; Briggs, Cheryl J.; Galina-Tessaro, Patricia; Valdez-Villavicencio, Jorge H.; Hollingsworth, Bradford; Shaffer, H. Bradley; Fisher, Robert N.

2018-01-01

 Chytridiomycosis is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) and is regarded as one of the most significant threats to global amphibian populations. In México, Bd was first reported in 2003 and has now been documented in 13 states. We visited 33 localities and swabbed 199 wild-caught anurans from 7 species (5 native, 2 exotic) across the Mediterranean region of the state of Baja California. Using quantitative PCR, Bd was detected in 94 individuals (47.2% of samples) at 25 of the 33 survey localities for 5 native and 1 exotic frog species. The exotic Xenopus laevis was the only species that tested completely negative for Bd. We found that remoteness, distance to agricultural land, and elevation were the best predictors of Bd presence. These are the first Bd-positive results for the state of Baja California and its presence should be regarded as an additional conservation threat to the region’s native frog species. 

Citizen scientists monitor a deadly fungus threatening amphibian communities in northern coastal California, USA

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Karen L. Pope; Greta M. Wengert; Janet E. Foley; Donald T. Ashton; Richard G. Botzler

2016-01-01

Ecoclub youth and supervising family members conducted citizen science to assess regional prevalence and distribution of Batrachochytrium dendrobatidis (Bd) among amphibians at Humboldt Bay National Wildlife Refuge (Refuge) and Redwood National and State Parks (Parks), Humboldt County, California, US, May 2013 through December...

Effects of the amphibian chytrid fungus and four insecticides on Pacific treefrogs (Pseudacris regilla)

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Kleinhez, Peter; Boone, Michelle D.; Fellers, Gary

2012-01-01

Chemical contamination may influence host-pathogen interactions, which has implications for amphibian population declines. We examined the effects of four insecticides alone or as a mixture on development and metamorphosis of Pacific Treefrogs (Pseudacris regilla) in the presence or absence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]). Bd exposure had a negative impact on tadpole activity, survival to metamorphosis, time to metamorphosis, and time of tail absorption (with a marginally negative effect on mass at metamorphosis); however, no individuals tested positive for Bd at metamorphosis. The presence of sublethal concentrations of insecticides alone or in a mixture did not impact Pacific Treefrog activity as tadpoles, survival to metamorphosis, or time and size to metamorphosis. Insecticide exposure did not influence the effect of Bd exposure. Our study did not support our prediction that effects of Bd would be greater in the presence of expected environmental concentrations of insecticide(s), but it did show that Bd had negative effects on responses at metamorphosis that could reduce the quality of juveniles recruited into the population.

Sodium chloride inhibits the growth and infective capacity of the amphibian chytrid fungus and increases host survival rates.

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Michelle Pirrie Stockwell

Full Text Available The amphibian chytrid fungus Batrachochytrium dendrobatidis is a recently emerged pathogen that causes the infectious disease chytridiomycosis and has been implicated as a contributing factor in the global amphibian decline. Since its discovery, research has been focused on developing various methods of mitigating the impact of chytridiomycosis on amphibian hosts but little attention has been given to the role of antifungal agents that could be added to the host's environment. Sodium chloride is a known antifungal agent used routinely in the aquaculture industry and this study investigates its potential for use as a disease management tool in amphibian conservation. The effect of 0-5 ppt NaCl on the growth, motility and survival of the chytrid fungus when grown in culture media and its effect on the growth, infection load and survivorship of infected Peron's tree frogs (Litoria peronii in captivity, was investigated. The results reveal that these concentrations do not negatively affect the survival of the host or the pathogen. However, concentrations greater than 3 ppt significantly reduced the growth and motility of the chytrid fungus compared to 0 ppt. Concentrations of 1-4 ppt NaCl were also associated with significantly lower host infection loads while infected hosts exposed to 3 and 4 ppt NaCl were found to have significantly higher survival rates. These results support the potential for NaCl to be used as an environmentally distributed antifungal agent for the prevention of chytridiomycosis in susceptible amphibian hosts. However, further research is required to identify any negative effects of salt exposure on both target and non-target organisms prior to implementation.

Patterns of Batrachochytrium dendrobatidis transmission between tadpoles in a high-elevation rainforest stream in tropical Australia.

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Hagman, Mattias; Alford, Ross A

2015-08-20

The highly virulent fungal pathogen Batrachochytrium dendrobatidis (Bd) poses a global threat to amphibian biodiversity. Streams and other water bodies are central habitats in the ecology of the disease, particularly in rainforests where they may transport and transmit the pathogen and harbor infected tadpoles that serve as reservoir hosts. We conducted an experiment using larval green-eyed tree frogs Litoria serrata in semi-natural streamside channels to test the hypotheses that (1) the fungus can be transmitted downstream in stream habitats and (2) infection affects tadpole growth and mouthpart loss. Our results showed that transmission can occur downstream in flowing water with no contact between individuals, that newly infected tadpoles suffered increased mouthpart loss in comparison with controls that were never infected and that infected tadpoles grew at reduced rates. Although recently infected tadpoles showed substantial loss of mouthparts, individuals with longstanding infections did not, suggesting that mouthparts may re-grow following initial loss. Our study suggests that any management efforts that can reduce the prevalence of infections in tadpoles may be particularly effective if applied in headwater areas, as their effects are likely to be felt downstream.

Current extinction rates of reptiles and amphibians.

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Alroy, John

2015-10-20

There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats.

Evidence of disease-related amphibian decline in Colorado

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Muths, Erin; Corn, Paul Stephen; Pessier, Allan P.; Green, D. Earl

2003-01-01

The recent discovery of a pathogenic fungus (Batrachochytrium dendrobatidis) associated with declines of frogs in the American and Australian tropics, suggests that at least the proximate cause, may be known for many previously unexplained amphibian declines. We have monitored boreal toads in Colorado since 1991 at four sites using capturea??recapture of adults and counts of egg masses to examine the dynamics of this metapopulation. Numbers of male toads declined in 1996 and 1999 with annual survival rate averaging 78% from 1991 to 1994, 45% in 1995 and 3% between 1998 and 1999. Numbers of egg masses also declined. An etiological diagnosis of chytridiomycosis consistent with infections by the genus Batrachochytrium was made in six wild adult toads. Characteristic histomorphological features (i.e. intracellular location, shape of thalli, presence of discharge tubes and rhizoids) of chytrid organisms, and host tissue response (acanthosis and hyperkeratosis) were observed in individual toads. These characteristics were indistinguishable from previously reported mortality events associated with chytrid fungus. We also observed epizootiological features consistent with mortality events associated with chytrid fungus: an increase in the ratio of female:male toads captured, an apparent spread of mortalities within the metapopulation and mortalities restricted to post metamorphic animals. Eleven years of population data suggest that this metapopulation of toads is in danger of extinction, pathological and epizootiological evidence indicates that B. dendrobatidis has played a proximate role in this process

Imperfect pathogen detection from non-invasive skin swabs biases disease inference

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DiRenzo, Graziella V.; Grant, Evan H. Campbell; Longo, Ana; Che-Castaldo, Christian; Zamudio, Kelly R.; Lips, Karen

2018-01-01

1. Conservation managers rely on accurate estimates of disease parameters, such as pathogen prevalence and infection intensity, to assess disease status of a host population. However, these disease metrics may be biased if low-level infection intensities are missed by sampling methods or laboratory diagnostic tests. These false negatives underestimate pathogen prevalence and overestimate mean infection intensity of infected individuals. 2. Our objectives were two-fold. First, we quantified false negative error rates of Batrachochytrium dendrobatidis on non-invasive skin swabs collected from an amphibian community in El Copé, Panama. We swabbed amphibians twice in sequence, and we used a recently developed hierarchical Bayesian estimator to assess disease status of the population. Second, we developed a novel hierarchical Bayesian model to simultaneously account for imperfect pathogen detection from field sampling and laboratory diagnostic testing. We evaluated the performance of the model using simulations and varying sampling design to quantify the magnitude of bias in estimates of pathogen prevalence and infection intensity. 3. We show that Bd detection probability from skin swabs was related to host infection intensity, where Bd infections information in advance, we advocate that the most cautious approach is to assume all errors are possible and to accommodate them by adjusting sampling designs. The modeling framework presented here improves the accuracy in estimating pathogen prevalence and infection intensity.

Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease.

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Rohr, Jason R; Raffel, Thomas R

2010-05-04

The role of global climate change in the decline of biodiversity and the emergence of infectious diseases remains controversial, and the effect of climatic variability, in particular, has largely been ignored. For instance, it was recently revealed that the proposed link between climate change and widespread amphibian declines, putatively caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), was tenuous because it was based on a temporally confounded correlation. Here we provide temporally unconfounded evidence that global El Niño climatic events drive widespread amphibian losses in genus Atelopus via increased regional temperature variability, which can reduce amphibian defenses against pathogens. Of 26 climate variables tested, only factors associated with temperature variability could account for the spatiotemporal patterns of declines thought to be associated with Bd. Climatic predictors of declines became significant only after controlling for a pattern consistent with epidemic spread (by temporally detrending the data). This presumed spread accounted for 59% of the temporal variation in amphibian losses, whereas El Niño accounted for 59% of the remaining variation. Hence, we could account for 83% of the variation in declines with these two variables alone. Given that global climate change seems to increase temperature variability, extreme climatic events, and the strength of Central Pacific El Niño episodes, climate change might exacerbate worldwide enigmatic declines of amphibians, presumably by increasing susceptibility to disease. These results suggest that changes to temperature variability associated with climate change might be as significant to biodiversity losses and disease emergence as changes to mean temperature.

Host-pathogen metapopulation dynamics suggest high elevation refugia for boreal toads

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Mosher, Brittany A.; Bailey, Larissa L.; Muths, Erin L.; Huyvaert, Kathryn P

2018-01-01

Emerging infectious diseases are an increasingly common threat to wildlife. Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease that has been linked to amphibian declines around the world. Few studies exist that explore amphibian-Bd dynamics at the landscape scale, limiting our ability to identify which factors are associated with variation in population susceptibility and to develop effective in situdisease management. Declines of boreal toads (Anaxyrus boreas boreas) in the Southern Rocky Mountains are largely attributed to chytridiomycosis but variation exists in local extinction of boreal toads across this metapopulation. Using a large-scale historic dataset, we explored several potential factors influencing disease dynamics in the boreal toad-Bd system: geographic isolation of populations, amphibian community richness, elevational differences, and habitat permanence. We found evidence that boreal toad extinction risk was lowest at high elevations where temperatures may be sub-optimal for Bd growth and where small boreal toad populations may be below the threshold needed for efficient pathogen transmission. In addition, boreal toads were more likely to recolonize high elevation sites after local extinction, again suggesting that high elevations may provide refuge from disease for boreal toads. We illustrate a modeling framework that will be useful to natural resource managers striving to make decisions in amphibian-Bdsystems. Our data suggest that in the southern Rocky Mountains high elevation sites should be prioritized for conservation initiatives like reintroductions.

Assessing the Threat of Amphibian Chytrid Fungus in the Albertine Rift: Past, Present and Future

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Seimon, Tracie A.; Ayebare, Samuel; Sekisambu, Robert; Muhindo, Emmanuel; Mitamba, Guillain; Greenbaum, Eli; Menegon, Michele; Pupin, Fabio; McAloose, Denise; Ammazzalorso, Alyssa; Meirte, Danny; Lukwago, Wilbur; Behangana, Mathias; Seimon, Anton; Plumptre, Andrew J.

2015-01-01

Batrachochytrium dendrobatidis (Bd), the cause of chytridiomycosis, is a pathogenic fungus that is found worldwide and is a major contributor to amphibian declines and extinctions. We report results of a comprehensive effort to assess the distribution and threat of Bd in one of the Earth’s most important biodiversity hotspots, the Albertine Rift in central Africa. In herpetological surveys conducted between 2010 and 2014, 1018 skin swabs from 17 amphibian genera in 39 sites across the Albertine Rift were tested for Bd by PCR. Overall, 19.5% of amphibians tested positive from all sites combined. Skin tissue samples from 163 amphibians were examined histologically; of these two had superficial epidermal intracorneal fungal colonization and lesions consistent with the disease chytridiomycosis. One amphibian was found dead during the surveys, and all others encountered appeared healthy. We found no evidence for Bd-induced mortality events, a finding consistent with other studies. To gain a historical perspective about Bd in the Albertine Rift, skin swabs from 232 museum-archived amphibians collected as voucher specimens from 1925–1994 were tested for Bd. Of these, one sample was positive; an Itombwe River frog (Phrynobatrachus asper) collected in 1950 in the Itombwe highlands. This finding represents the earliest record of Bd in the Democratic Republic of Congo. We modeled the distribution of Bd in the Albertine Rift using MaxEnt software, and trained our model for improved predictability. Our model predicts that Bd is currently widespread across the Albertine Rift, with moderate habitat suitability extending into the lowlands. Under climatic modeling scenarios our model predicts that optimal habitat suitability of Bd will decrease causing a major range contraction of the fungus by 2080. Our baseline data and modeling predictions are important for comparative studies, especially if significant changes in amphibian health status or climactic conditions are

Composition of Micro-eukaryotes on the Skin of the Cascades Frog (Rana cascadae and Patterns of Correlation between Skin Microbes and Batrachochytrium dendrobatidis

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Jordan G. Kueneman

2017-12-01

Full Text Available Global amphibian decline linked to fungal pathogens has galvanized research on applied amphibian conservation. Skin-associated bacterial communities of amphibians have been shown to mediate fungal skin infections and the development of probiotic treatments with antifungal bacteria has become an emergent area of research. While exploring the role of protective bacteria has been a primary focus for amphibian conservation, we aim to expand and study the other microbes present in amphibian skin communities including fungi and other micro-eukaryotes. Here, we characterize skin-associated bacteria and micro-eukaryotic diversity found across life stages of Cascades frog (Rana cascadae and their associated aquatic environments using culture independent 16S and 18S rRNA marker-gene sequencing. Individuals of various life stages of Cascades frogs were sampled from a population located in the Trinity Alps in Northern California during an epidemic of the chytrid fungus, Batrachochytrium dendrobatidis. We filtered the bacterial sequences against a published database of bacteria known to inhibit B. dendrobatidis in co-culture to estimate the proportion of the skin bacterial community that is likely to provide defense against B. dendrobatidis. Tadpoles had a significantly higher proportion of B. dendrobatidis-inhibitory bacterial sequence matches relative to subadult and adult Cascades frogs. We applied a network analysis to examine patterns of correlation between bacterial taxa and B. dendrobatidis, as well as micro-eukaryotic taxa and B. dendrobatidis. Combined with the published database of bacteria known to inhibit B. dendrobatidis, we used the network analysis to identify bacteria that negatively correlated with B. dendrobatidis and thus could be good probiotic candidates in the Cascades frog system.

Disease risk in temperate amphibian populations is higher at closed-canopy sites.

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C Guilherme Becker

Full Text Available Habitat loss and chytridiomycosis (a disease caused by the chytrid fungus Batrachochytrium dendrobatidis - Bd are major drivers of amphibian declines worldwide. Habitat loss regulates host-pathogen interactions by altering biotic and abiotic factors directly linked to both host and pathogen fitness. Therefore, studies investigating the links between natural vegetation and chytridiomycosis require integrative approaches to control for the multitude of possible interactions of biological and environmental variables in spatial epidemiology. In this study, we quantified Bd infection dynamics across a gradient of natural vegetation and microclimates, looking for causal associations between vegetation cover, multiple microclimatic variables, and pathogen prevalence and infection intensity. To minimize the effects of host diversity in our analyses, we sampled amphibian populations in the Adirondack Mountains of New York State, a region with relatively high single-host dominance. We sampled permanent ponds for anurans, focusing on populations of the habitat generalist frog Lithobates clamitans, and recorded various biotic and abiotic factors that potentially affect host-pathogen interactions: natural vegetation, canopy density, water temperature, and host population and community attributes. We screened for important explanatory variables of Bd infections and used path analyses to statistically test for the strength of cascading effects linking vegetation cover, microclimate, and Bd parameters. We found that canopy density, natural vegetation, and daily average water temperature were the best predictors of Bd. High canopy density resulted in lower water temperature, which in turn predicted higher Bd prevalence and infection intensity. Our results confirm that microclimatic shifts arising from changes in natural vegetation play an important role in Bd spatial epidemiology, with areas of closed canopy favoring Bd. Given increasing rates of anthropogenic

Extremely low prevalence of Batrachochytrium dendrobatidis in frog populations from neotropical dry forest of Costa Rica supports the existence of a climatic refuge from disease.

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Zumbado-Ulate, Héctor; Bolaños, Federico; Gutiérrez-Espeleta, Gustavo; Puschendorf, Robert

2014-12-01

Population declines and extinctions of numerous species of amphibians, especially stream-breeding frogs, have been linked to the emerging infectious disease chytridiomycosis, caused by the chytrid fungus, Batrachochytrium dendrobatidis. In Central America, most of the 34 species of the Craugastor punctariolus species group have disappeared in recent years in high- and low-elevation rainforests. Distribution models for B. dendrobatidis and the continuous presence of the extirpated stream-dwelling species, Craugastor ranoides, in the driest site of Costa Rica (Santa Elena Peninsula), suggest that environmental conditions might restrict the growth and development of B. dendrobatidis, existing as a refuge from chytridiomycosis-driven extinction. We conducted field surveys to detect and quantify the pathogen using Real-time PCR in samples from 15 species of frogs in two locations of tropical dry forest. In Santa Elena Peninsula, we swabbed 310 frogs, and only one sample of the species, C. ranoides, tested positive for B. dendrobatidis (prevalence dry and hot environments of tropical dry forest. This study supports the existence of climatic refuges from chytridiomycosis and highlights the importance of tropical dry forest conservation for amphibians in the face of epidemic disease.

Swabbing often fails to detect amphibian Chytridiomycosis under conditions of low infection load.

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Jaehyub Shin

Full Text Available The pathogenic chytrid fungus, Batrachochytrium dendrobatidis (denoted Bd, causes large-scale epizootics in naïve amphibian populations. Intervention strategies to rapidly respond to Bd incursions require sensitive and accurate diagnostic methods. Chytridiomycosis usually is assessed by quantitative polymerase chain reaction (qPCR amplification of amphibian skin swabs. Results based on this method, however, sometimes yield inconsistent results on infection status and inaccurate scores of infection intensity. In Asia and other regions where amphibians typically bear low Bd loads, swab results are least reliable. We developed a Bd-sampling method that collects zoospores released by infected subjects into an aquatic medium. Bd DNA is extracted by filters and amplified by nested PCR. Using laboratory colonies and field populations of Bombina orientalis, we compare results with those obtained on the same subjects by qPCR of DNA extracted from swabs. Many subjects, despite being diagnosed as Bd-negative by conventional methods, released Bd zoospores into collection containers and thus must be considered infected. Infection loads determined from filtered water were at least 1000 times higher than those estimated from swabs. Subjects significantly varied in infection load, as they intermittently released zoospores, over a 5-day period. Thus, the method might be used to compare the infectivity of individuals and study the periodicity of zoospore release. Sampling methods based on water filtration can dramatically increase the capacity to accurately diagnose chytridiomycosis and contribute to a better understanding of the interactions between Bd and its hosts.

Batrachochytrium salamandrivorans: The North American response and a call for action

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Matthew J. Gray; James P. Lewis; Priya Nanjappa; Blake Klocke; Frank Pasmans; An Martel; Craig Stephen; Gabriela Parra Olea; Scott A. Smith; Allison Sacerdote-Velat; Michelle R. Christman; Jennifer M. Williams; Deanna H. Olson; Deborah A. Hogan

2015-01-01

Batrachochytrium salamandrivorans (Bsal) is an emerging fungal pathogen that has caused recent die-offs of native salamanders in Europe and is known to be lethal to at least some North American species in laboratory trials [1]. Bsal appears to have originated in Asia, and may have been introduced by humans...

Additive threats from pathogens, climate and land-use change for global amphibian diversity

DEFF Research Database (Denmark)

Hof, Christian; Bastos Araujo, Miguel; Jetz, Walter

2011-01-01

Amphibian population declines far exceed those of other vertebrate groups, with 30% of all species listed as threatened by the International Union for Conservation of Nature. The causes of these declines are a matter of continued research, but probably include climate change, land-use change...... to be found in Africa, parts of northern South America and the Andes. Regions with the highest projected impact of land-use and climate change coincide, but there is little spatial overlap with regions highly threatened by the fungal disease. Overall, the areas harbouring the richest amphibian faunas...... and spread of the pathogenic fungal disease chytridiomycosis. Here we assess the spatial distribution and interactions of these primary threats in relation to the global distribution of amphibian species. We show that the greatest proportions of species negatively affected by climate change are projected...

The Emerging Amphibian Fungal Disease, Chytridiomycosis: A Key Example of the Global Phenomenon of Wildlife Emerging Infectious Diseases.

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Kolby, Jonathan E; Daszak, Peter

2016-06-01

The spread of amphibian chytrid fungus, Batrachochytrium dendrobatidis, is associated with the emerging infectious wildlife disease chytridiomycosis. This fungus poses an overwhelming threat to global amphibian biodiversity and is contributing toward population declines and extinctions worldwide. Extremely low host-species specificity potentially threatens thousands of the 7,000+ amphibian species with infection, and hosts in additional classes of organisms have now also been identified, including crayfish and nematode worms.Soon after the discovery of B. dendrobatidis in 1999, it became apparent that this pathogen was already pandemic; dozens of countries and hundreds of amphibian species had already been exposed. The timeline of B. dendrobatidis's global emergence still remains a mystery, as does its point of origin. The reason why B. dendrobatidis seems to have only recently increased in virulence to catalyze this global disease event remains unknown, and despite 15 years of investigation, this wildlife pandemic continues primarily uncontrolled. Some disease treatments are effective on animals held in captivity, but there is currently no proven method to eradicate B. dendrobatidis from an affected habitat, nor have we been able to protect new regions from exposure despite knowledge of an approaching "wave" of B. dendrobatidis and ensuing disease.International spread of B. dendrobatidis is largely facilitated by the commercial trade in live amphibians. Chytridiomycosis was recently listed as a globally notifiable disease by the World Organization for Animal Health, but few countries, if any, have formally adopted recommended measures to control its spread. Wildlife diseases continue to emerge as a consequence of globalization, and greater effort is urgently needed to protect global health.

CRN13 candidate effectors from plant and animal eukaryotic pathogens are DNA-binding proteins which trigger host DNA damage response.

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Ramirez-Garcés, Diana; Camborde, Laurent; Pel, Michiel J C; Jauneau, Alain; Martinez, Yves; Néant, Isabelle; Leclerc, Catherine; Moreau, Marc; Dumas, Bernard; Gaulin, Elodie

2016-04-01

To successfully colonize their host, pathogens produce effectors that can interfere with host cellular processes. Here we investigated the function of CRN13 candidate effectors produced by plant pathogenic oomycetes and detected in the genome of the amphibian pathogenic chytrid fungus Batrachochytrium dendrobatidis (BdCRN13). When expressed in Nicotiana, AeCRN13, from the legume root pathogen Aphanomyces euteiches, increases the susceptibility of the leaves to the oomycete Phytophthora capsici. When transiently expressed in amphibians or plant cells, AeCRN13 and BdCRN13 localize to the cell nuclei, triggering aberrant cell development and eventually causing cell death. Using Förster resonance energy transfer experiments in plant cells, we showed that both CRN13s interact with nuclear DNA and trigger plant DNA damage response (DDR). Mutating key amino acid residues in a predicted HNH-like endonuclease motif abolished the interaction of AeCRN13 with DNA, the induction of DDR and the enhancement of Nicotiana susceptibility to P. capsici. Finally, H2AX phosphorylation, a marker of DNA damage, and enhanced expression of genes involved in the DDR were observed in A. euteiches-infected Medicago truncatula roots. These results show that CRN13 from plant and animal eukaryotic pathogens promotes host susceptibility by targeting nuclear DNA and inducing DDR. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Introduced bullfrogs are associated with increased Batrachochytrium dendrobatidis prevalence and reduced occurrence of Korean treefrogs.

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Amaël Borzée

Full Text Available Bullfrogs, Lithobates catesbeianus, have been described as major vectors of the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd. Bd is widespread throughout the range of amphibians yet varies considerably within and among populations in prevalence and host impact. In our study, the presence of L. catesbeianus is correlated with a 2.5 increase in Bd prevalence in treefrogs, and the endangered Dryophytes suweonensis displays a significantly higher Bd prevalence than the more abundant D. japonicus for the 37 sites surveyed. In addition, the occurrence of L. catesbeianus was significantly correlated with a decrease in presence of D. suweonensis at sites. We could not determine if it is the presence of bullfrogs as competitors or predators that is limiting the distribution of D. suweonensis or whether this is caused by bullfrogs acting as a reservoir for Bd. However, L. catesbeianus can now be added to the list of factors responsible for the decline of D. suweonensis populations.

The Effect of Human Impact on Batrachochytrium dendrobatidis prevalence in Taricha torosa

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Deng, V.; Macario, E.; Tumey, C.

2014-12-01

Batrachochytrium dendrobatidis (Bd) is emerging as a major cause of the amphibian extinction. As amphibians serve an important role as indicator species in their ecosystem and play a vital role in the food chain, Bd will not only affect the amphibian population but also the health of the environment. Bd is an aquatic fungus that blocks the porous skin of amphibians which interrupts electrolyte, gas and water transfer. This imbalances the electrolyte system which causes cells and organs to malfunction, therefore killing the amphibian. While frogs are more common for Bd, it is not often found in newts. However, Dr. Vance Vredenburg recently found an outbreak of Bd in Taricha torosa in Marin Headlands, California. This location was used in the research as the sample site with most human impact and was expected to have the highest prevalence according to the proposed hypothesis that more human impact will correspond with a higher prevalence of Bd. Decreasing the level of human impact, Fairfield Osborn Preserve and Galbreath Preserve were picked as the other sample sites. After the samples went through qPCR, all of them came back negative for Bd. These results did not support the hypothesis, however, it contributed data to explaining the dynamics of Bd when combined with Dr. Vance Vredenburg's data from 2 months earlier. Within the two months, there was a huge difference in the prevalence of Bd as it dropped from 88% to 0%. This shows that Taricha torosa does in fact get Bd. However, it is rarely detected because Bd is fast-acting and has high mortality rates. Therefore, it is least likely for current nonspecific surveys to swab the newts during a short but lethal Bd outbreak.

Salamander chytrid fungus (Batrachochytrium salamandrivorans) in the United States—Developing research, monitoring, and management strategies

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Grant, Evan H. Campbell; Muths, Erin L.; Katz, Rachel A.; Canessa, Stefano; Adams, Michael J.; Ballard, Jennifer R.; Berger, Lee; Briggs, Cheryl J.; Coleman, Jeremy; Gray, Matthew J.; Harris, M. Camille; Harris, Reid N.; Hossack, Blake R.; Huyvaert, Kathryn P.; Kolby, Jonathan E.; Lips, Karen R.; Lovich, Robert E.; McCallum, Hamish I.; Mendelson, Joseph R.; Nanjappa, Priya; Olson, Deanna H.; Powers, Jenny G.; Richgels, Katherine L. D.; Russell, Robin E.; Schmidt, Benedikt R.; Spitzen-van der Sluijs, Annemarieke; Watry, Mary Kay; Woodhams, Douglas C.; White, C. LeAnn

2016-01-20

The recently (2013) identified pathogenic chytrid fungus, Batrachochytrium salamandrivorans (Bsal), poses a severe threat to the distribution and abundance of salamanders within the United States and Europe. Development of a response strategy for the potential, and likely, invasion of Bsal into the United States is crucial to protect global salamander biodiversity. A formal working group, led by Amphibian Research and Monitoring Initiative (ARMI) scientists from the U.S. Geological Survey (USGS) Patuxent Wildlife Research Center, Fort Collins Science Center, and Forest and Rangeland Ecosystem Science Center, was held at the USGS Powell Center for Analysis and Synthesis in Fort Collins, Colorado, United States from June 23 to June 25, 2015, to identify crucial Bsal research and monitoring needs that could inform conservation and management strategies for salamanders in the United States. Key findings of the workshop included the following: (1) the introduction of Bsal into the United States is highly probable, if not inevitable, thus requiring development of immediate short-term and long-term intervention strategies to prevent Bsal establishment and biodiversity decline; (2) management actions targeted towards pathogen containment may be ineffective in reducing the long-term spread of Bsal throughout the United States; and (3) early detection of Bsal through surveillance at key amphibian import locations, among high-risk wild populations, and through analysis of archived samples is necessary for developing management responses. Top research priorities during the preinvasion stage included the following: (1) deployment of qualified diagnostic methods for Bsal and establishment of standardized laboratory practices, (2) assessment of susceptibility for amphibian hosts (including anurans), and (3) development and evaluation of short- and long-term pathogen intervention and management strategies. Several outcomes were achieved during the workshop, including development

Effects of amphibian phylogeny, climate and human impact on the occurrence of the amphibian-killing chytrid fungus.

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Bacigalupe, Leonardo D; Soto-Azat, Claudio; García-Vera, Cristobal; Barría-Oyarzo, Ismael; Rezende, Enrico L

2017-09-01

Chytridiomycosis, due to the fungus Batrachochytrium dendrobatidis (Bd), has been associated with the alarming decline and extinction crisis of amphibians worldwide. Because conservation programs are implemented locally, it is essential to understand how the complex interactions among host species, climate and human activities contribute to Bd occurrence at regional scales. Using weighted phylogenetic regressions and model selection, we investigated geographic patterns of Bd occurrence along a latitudinal gradient of 1500 km within a biodiversity hot spot in Chile (1845 individuals sampled from 253 sites and representing 24 species), and its association with climatic, socio-demographic and economic variables. Analyses show that Bd prevalence decreases with latitude although it has increased by almost 10% between 2008 and 2013, possibly reflecting an ongoing spread of Bd following the introduction of Xenopus laevis. Occurrence of Bd was higher in regions with high gross domestic product (particularly near developed centers) and with a high variability in rainfall regimes, whereas models including other bioclimatic or geographic variables, including temperature, exhibited substantially lower fit and virtually no support based on Akaike weights. In addition, Bd prevalence exhibited a strong phylogenetic signal, with five species having high numbers of infected individuals and higher prevalence than the average of 13.3% across all species. Taken together, our results highlight that Bd in Chile might still be spreading south, facilitated by a subset of species that seem to play an important epidemiological role maintaining this pathogen in the communities, in combination with climatic and human factors affecting the availability and quality of amphibian breeding sites. This information may be employed to design conservation strategies and mitigate the impacts of Bd in the biodiversity hot spot of southern Chile, and similar studies may prove useful to disentangle the

BIOTIC FACTORS IN AMPHIBIAN POPULATION DECLINES

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Amphibians evolved in, and continue to exist in, habitats that are replete with many other organisms. Some of these organisms serve as prey for amphibians and others interact with amphibians as predators, competitors, pathogens, or symbionts. Still other organisms in their enviro...

76 FR 61956 - Endangered and Threatened Wildlife and Plants; Endangered Status for the Ozark Hellbender Salamander

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2011-10-06

... stated that animals infected with Batrachochytrium dendrobatidis (the pathogen which causes amphibian... seq.) is a law that was passed to prevent extinction of species by providing measures to help alleviate the loss of species and their habitats. Before a plant or animal species can receive the...

Effects of pesticide exposure and the amphibian chytrid fungus on gray treefrog (Hyla chrysoscelis) metamorphosis.

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Gaietto, Kristina M; Rumschlag, Samantha L; Boone, Michelle D

2014-10-01

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. © 2014 SETAC.

Historical amphibian declines and extinctions in Brazil linked to chytridiomycosis.

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Carvalho, Tamilie; Becker, C Guilherme; Toledo, Luís Felipe

2017-02-08

The recent increase in emerging fungal diseases is causing unprecedented threats to biodiversity. The origin of spread of the frog-killing fungus Batrachochytrium dendrobatidis ( Bd ) is a matter of continued debate. To date, the historical amphibian declines in Brazil could not be attributed to chytridiomycosis; the high diversity of hosts coupled with the presence of several Bd lineages predating the reported declines raised the hypothesis that a hypervirulent Bd genotype spread from Brazil to other continents causing the recent global amphibian crisis. We tested for a spatio-temporal overlap between Bd and areas of historical amphibian population declines and extinctions in Brazil. A spatio-temporal convergence between Bd and declines would support the hypothesis that Brazilian amphibians were not adapted to Bd prior to the reported declines, thus weakening the hypothesis that Brazil was the global origin of Bd emergence. Alternatively, a lack of spatio-temporal association between Bd and frog declines would indicate an evolution of host resistance in Brazilian frogs predating Bd 's global emergence , further supporting Brazil as the potential origin of the Bd panzootic. Here, we Bd -screened over 30 000 museum-preserved tadpoles collected in Brazil between 1930 and 2015 and overlaid spatio-temporal Bd data with areas of historical amphibian declines. We detected an increase in the proportion of Bd -infected tadpoles during the peak of amphibian declines (1979-1987). We also found that clusters of Bd -positive samples spatio-temporally overlapped with most records of amphibian declines in Brazil's Atlantic Forest. Our findings indicate that Brazil is post epizootic for chytridiomycosis and provide another piece to the puzzle to explain the origin of Bd globally. © 2017 The Author(s).

Historical amphibian declines and extinctions in Brazil linked to chytridiomycosis

Science.gov (United States)

Carvalho, Tamilie; Becker, C. Guilherme

2017-01-01

The recent increase in emerging fungal diseases is causing unprecedented threats to biodiversity. The origin of spread of the frog-killing fungus Batrachochytrium dendrobatidis (Bd) is a matter of continued debate. To date, the historical amphibian declines in Brazil could not be attributed to chytridiomycosis; the high diversity of hosts coupled with the presence of several Bd lineages predating the reported declines raised the hypothesis that a hypervirulent Bd genotype spread from Brazil to other continents causing the recent global amphibian crisis. We tested for a spatio-temporal overlap between Bd and areas of historical amphibian population declines and extinctions in Brazil. A spatio-temporal convergence between Bd and declines would support the hypothesis that Brazilian amphibians were not adapted to Bd prior to the reported declines, thus weakening the hypothesis that Brazil was the global origin of Bd emergence. Alternatively, a lack of spatio-temporal association between Bd and frog declines would indicate an evolution of host resistance in Brazilian frogs predating Bd's global emergence, further supporting Brazil as the potential origin of the Bd panzootic. Here, we Bd-screened over 30 000 museum-preserved tadpoles collected in Brazil between 1930 and 2015 and overlaid spatio-temporal Bd data with areas of historical amphibian declines. We detected an increase in the proportion of Bd-infected tadpoles during the peak of amphibian declines (1979–1987). We also found that clusters of Bd-positive samples spatio-temporally overlapped with most records of amphibian declines in Brazil's Atlantic Forest. Our findings indicate that Brazil is post epizootic for chytridiomycosis and provide another piece to the puzzle to explain the origin of Bd globally. PMID:28179514

Amphibian Chytrid Fungus in Madagascar neither Shows Widespread Presence nor Signs of Certain Establishment.

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Kolby, Jonathan E; Skerratt, Lee F

2015-01-01

The global spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) is associated with amphibian mass mortality, population decline, and extinction. Over the past decade, concern has been expressed for the potential introduction of Bd to Madagascar, a global hotspot of amphibian biodiversity. Following years without detection, widespread Bd presence in Madagascar has now been reported (Bletz et al. 2015a), raising international conservation concern. Before reacting to this finding with a significant management response, the accuracy and context of the data warrant cautious review. Re-examination of a 10-year dataset together with results from more recent surveillance (Kolby et al. 2015) does not yet demonstrate widespread Bd presence. Detection of Bd at "positive" locations in Madagascar has been inconsistent for unknown reasons. Whether Bd is established in Madagascar (i.e. populations are self-sustaining) or instead requires continued introduction to persist also remains uncertain. The deployment of emergency conservation rescue initiatives is expected to target areas where the distribution of Bd and the risk of chytridiomycosis endangering amphibians is believed to overlap. Thus, erroneous description of Bd presence would misdirect limited conservation resources. Standardized surveillance and confirmatory surveys are now imperative to reliably characterize the distribution, potential spread, virulence and overall risk of Bd to amphibians in Madagascar.

Amphibian Chytrid Fungus in Madagascar neither Shows Widespread Presence nor Signs of Certain Establishment.

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Jonathan E Kolby

Full Text Available The global spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd is associated with amphibian mass mortality, population decline, and extinction. Over the past decade, concern has been expressed for the potential introduction of Bd to Madagascar, a global hotspot of amphibian biodiversity. Following years without detection, widespread Bd presence in Madagascar has now been reported (Bletz et al. 2015a, raising international conservation concern. Before reacting to this finding with a significant management response, the accuracy and context of the data warrant cautious review. Re-examination of a 10-year dataset together with results from more recent surveillance (Kolby et al. 2015 does not yet demonstrate widespread Bd presence. Detection of Bd at "positive" locations in Madagascar has been inconsistent for unknown reasons. Whether Bd is established in Madagascar (i.e. populations are self-sustaining or instead requires continued introduction to persist also remains uncertain. The deployment of emergency conservation rescue initiatives is expected to target areas where the distribution of Bd and the risk of chytridiomycosis endangering amphibians is believed to overlap. Thus, erroneous description of Bd presence would misdirect limited conservation resources. Standardized surveillance and confirmatory surveys are now imperative to reliably characterize the distribution, potential spread, virulence and overall risk of Bd to amphibians in Madagascar.

The role of 'atypical' Brucella in amphibians: are we facing novel emerging pathogens?

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Mühldorfer, K; Wibbelt, G; Szentiks, C A; Fischer, D; Scholz, H C; Zschöck, M; Eisenberg, T

2017-01-01

To discuss together the novel cases of Brucella infections in frogs with the results of published reports to extend our current knowledge on 'atypical' brucellae isolated from amphibians and to discuss the challenges we face on this extraordinary emerging group of pathogens. Since our first description, an additional 14 isolates from four different frog species were collected. Novel isolates and a subset of Brucella isolates previously cultured from African bullfrogs were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), Fourier transform-infrared (FT-IR) spectroscopy and broth microdilution susceptibility testing. MALDI-TOF MS worked very efficiently for an accurate bacterial identification to the genus level. Within the cluster analysis, 'atypical' brucellae grouped distant from Brucella melitensis and were even more separated by FT-IR spectroscopy with respect to their geographical origin. Minimum inhibitory concentrations of 14 antimicrobial substances are provided as baseline data on antimicrobial susceptibility. The case history of Brucella infections in amphibians reveals a variety of pathologies ranging from localized manifestations to systemic infections. Some isolates seem to be capable of causing high mortality in zoological exhibitions putting higher demands on the management of endangered frog species. There is considerable risk in overlooking and misidentifying 'atypical' Brucella in routine diagnostics. Brucella have only recently been described in cold-blooded vertebrates. Their presence in frog species native to Africa, America and Australia indicates a more common occurrence in amphibians than previously thought. This study provides an extensive overview of amphibian brucellae by highlighting the main features of their clinical significance, diagnosis and zoonotic potential. © 2016 The Society for Applied Microbiology.

Culture Media and Individual Hosts Affect the Recovery of Culturable Bacterial Diversity from Amphibian Skin.

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Medina, Daniel; Walke, Jenifer B; Gajewski, Zachary; Becker, Matthew H; Swartwout, Meredith C; Belden, Lisa K

2017-01-01

One current challenge in microbial ecology is elucidating the functional roles of the large diversity of free-living and host-associated bacteria identified by culture-independent molecular methods. Importantly, the characterization of this immense bacterial diversity will likely require merging data from culture-independent approaches with work on bacterial isolates in culture. Amphibian skin bacterial communities have become a recent focus of work in host-associated microbial systems due to the potential role of these skin bacteria in host defense against the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which is associated with global amphibian population declines and extinctions. As there is evidence that some skin bacteria may inhibit growth of Bd and prevent infection in some cases, there is interest in using these bacteria as probiotic therapy for conservation of at-risk amphibians. In this study, we used skin swabs from American toads ( Anaxyrus americanus ) to: (1) assess the diversity and community structure of culturable amphibian skin bacteria grown on high and low nutrient culture media, (2) determine which culture media recover the highest proportion of the total skin bacterial community of individual toads relative to culture-independent data, and (3) assess whether the plated communities from the distinct media types vary in their ability to inhibit Bd growth in in-vitro assays. Overall, we found that culture media with low nutrient concentrations facilitated the growth of more diverse bacterial taxa and grew distinct communities relative to media with higher nutrient concentrations. Use of low nutrient media also resulted in culturing proportionally more of the bacterial diversity on individual toads relative to the overall community defined using culture-independent methods. However, while there were differences in diversity among media types, the variation among individual hosts was greater than variation among media types, suggesting

Interventions for reducing extinction risk in chytridiomycosis-threatened amphibians.

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Scheele, Ben C; Hunter, David A; Grogan, Laura F; Berger, Lee; Kolby, Jon E; McFadden, Michael S; Marantelli, Gerry; Skerratt, Lee F; Driscoll, Don A

2014-10-01

Wildlife diseases pose an increasing threat to biodiversity and are a major management challenge. A striking example of this threat is the emergence of chytridiomycosis. Despite diagnosis of chytridiomycosis as an important driver of global amphibian declines 15 years ago, researchers have yet to devise effective large-scale management responses other than biosecurity measures to mitigate disease spread and the establishment of disease-free captive assurance colonies prior to or during disease outbreaks. We examined the development of management actions that can be implemented after an epidemic in surviving populations. We developed a conceptual framework with clear interventions to guide experimental management and applied research so that further extinctions of amphibian species threatened by chytridiomycosis might be prevented. Within our framework, there are 2 management approaches: reducing Batrachochytrium dendrobatidis (the fungus that causes chytridiomycosis) in the environment or on amphibians and increasing the capacity of populations to persist despite increased mortality from disease. The latter approach emphasizes that mitigation does not necessarily need to focus on reducing disease-associated mortality. We propose promising management actions that can be implemented and tested based on current knowledge and that include habitat manipulation, antifungal treatments, animal translocation, bioaugmentation, head starting, and selection for resistance. Case studies where these strategies are being implemented will demonstrate their potential to save critically endangered species. © 2014 Society for Conservation Biology.

The cause of global amphibian declines: a developmental endocrinologist's perspective.

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Hayes, T B; Falso, P; Gallipeau, S; Stice, M

2010-03-15

Greater than 70% of the world's amphibian species are in decline. We propose that there is probably not a single cause for global amphibian declines and present a three-tiered hierarchical approach that addresses interactions among and between ultimate and proximate factors that contribute to amphibian declines. There are two immediate (proximate) causes of amphibian declines: death and decreased recruitment (reproductive failure). Although much attention has focused on death, few studies have addressed factors that contribute to declines as a result of failed recruitment. Further, a great deal of attention has focused on the role of pathogens in inducing diseases that cause death, but we suggest that pathogen success is profoundly affected by four other ultimate factors: atmospheric change, environmental pollutants, habitat modification and invasive species. Environmental pollutants arise as likely important factors in amphibian declines because they have realized potential to affect recruitment. Further, many studies have documented immunosuppressive effects of pesticides, suggesting a role for environmental contaminants in increased pathogen virulence and disease rates. Increased attention to recruitment and ultimate factors that interact with pathogens is important in addressing this global crisis.

First record of Saprolegnia sp. in an amphibian population in Colombia

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Luis Daniel Prada-Salcedo

2011-12-01

Full Text Available Most research related to the decline of amphibians has been focused on the detection of the pathogenic fungus Batrachochytriumdendrobatidis. This fungus is the main pathogen detected around the world. However, research has shown the presence of another fungus,Saprolegnia ferax, as a cause of mortality in amphibians in North America. Our study suggests a possible interspecific transmissioncaused by the presence of rainbow trout; thus, amphibian declines may not be attributable only to the presence of a single pathogen, butto other organisms and factors. Materials and methods. Our study revealed the presence of Saprolegnia sp. in the Andean frog Atelopusmittermeieri using the imprinting technique with lactophenol blue staining, which allowed the typical structures of this fungus to beobserved. Results. The importance of this discovery is the presence of two pathogenic fungi, B. dendrobatidis and Saprolegnia, whichaffecting simultaneously a population of amphibians. This finding brings attention to the eventual presence of other microorganismsthat might be involved individually or collectively in the decline of amphibian species. Conclusions. This record suggests a possibletransmission between rainbow trout (Oncorhynchus mykiss, an introduced species in the highlands of Colombia, which shares thesame habitats with different species of amphibians in the Sanctuary of Flora and Fauna Guanentá in the upper river Fonce in the midCordillera Oriental of Colombia.

Nothing a hot bath won't cure: infection rates of amphibian chytrid fungus correlate negatively with water temperature under natural field settings.

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Forrest, Matthew J; Schlaepfer, Martin A

2011-01-01

Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd). Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis), from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10-50°C), including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75-100% in water 30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications.There must be quite a few things a hot bath won't cure, but I don't know many of them--Sylvia Plath, "The Bell Jar" (1963).

Nothing a hot bath won't cure: infection rates of amphibian chytrid fungus correlate negatively with water temperature under natural field settings.

Directory of Open Access Journals (Sweden)

Matthew J Forrest

Full Text Available Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd. Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis, from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10-50°C, including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75-100% in water 30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications.There must be quite a few things a hot bath won't cure, but I don't know many of them--Sylvia Plath, "The Bell Jar" (1963.

Spatial variation in risk and consequence of Batrachochytrium salamandrivorans introduction in the USA

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Richgels, Katherine L. D.; Russell, Robin E.; Adams, Michael J.; White, C. LeAnn; Campbell Grant, Evan H.

2016-01-01

A newly identified fungal pathogen, Batrachochytrium salamandrivorans (Bsal), is responsible for mass mortality events and severe population declines in European salamanders. The eastern USA has the highest diversity of salamanders in the world and the introduction of this pathogen is likely to be devastating. Although data are inevitably limited for new pathogens, disease-risk assessments use best available data to inform management decisions. Using characteristics of Bsal ecology, spatial data on imports and pet trade establishments, and salamander species diversity, we identify high-risk areas with both a high likelihood of introduction and severe consequences for local salamanders. We predict that the Pacific coast, southern Appalachian Mountains and mid-Atlantic regions will have the highest relative risk from Bsal. Management of invasive pathogens becomes difficult once they are established in wildlife populations; therefore, import restrictions to limit pathogen introduction and early detection through surveillance of high-risk areas are priorities for preventing the next crisis for North American salamanders.

Emerging Ranaviral Infectious Diseases and Amphibian Decline

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Jacques Robert

2010-02-01

Full Text Available Infectious diseases caused by ranaviruses (RV, family Iridoviridae not only affect wild amphibian populations but also agriculture and international animal trade. Although, the prevalence of RV infections and die offs has markedly increased over the last decade, it is still unclear whether these viruses are direct causal agents of extinction or rather are the resulting (secondary consequences of weakened health of amphibian populations leading to increased susceptibility to viral pathogens. In either case, it is important to understand the critical role of host immune defense in controlling RV infections, pathogenicity, and transmission; this is the focus of this review.

Mitigating amphibian chytridiomycosis in nature

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Garner, Trenton W. J.; Schmidt, Benedikt R.; Martel, An; Pasmans, Frank; Muths, Erin L.; Cunningham, Andrew A.; Weldon, Che; Fisher, Matthew C.; Bosch, Jaime

2016-01-01

Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems.

Ecopathology of Ranaviruses Infecting Amphibians

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Andrew Storfer

2011-11-01

Full Text Available Ranaviruses are capable of infecting amphibians from at least 14 families and over 70 individual species. Ranaviruses infect multiple cell types, often culminating in organ necrosis and massive hemorrhaging. Subclinical infections have been documented, although their role in ranavirus persistence and emergence remains unclear. Water is an effective transmission medium for ranaviruses, and survival outside the host may be for significant duration. In aquatic communities, amphibians, reptiles and fish may serve as reservoirs. Controlled studies have shown that susceptibility to ranavirus infection and disease varies among amphibian species and developmental stages, and likely is impacted by host-pathogen coevolution, as well as, exogenous environmental factors. Field studies have demonstrated that the likelihood of epizootics is increased in areas of cattle grazing, where aquatic vegetation is sparse and water quality is poor. Translocation of infected amphibians through commercial trade (e.g., food, fish bait, pet industry contributes to the spread of ranaviruses. Such introductions may be of particular concern, as several studies report that ranaviruses isolated from ranaculture, aquaculture, and bait facilities have greater virulence (i.e., ability to cause disease than wild-type isolates. Future investigations should focus on the genetic basis for pathogen virulence and host susceptibility, ecological and anthropogenic mechanisms contributing to emergence, and vaccine development for use in captive populations and species reintroduction programs.

Evaluating the links between climate, disease spread, and amphibian declines.

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Rohr, Jason R; Raffel, Thomas R; Romansic, John M; McCallum, Hamish; Hudson, Peter J

2008-11-11

Human alteration of the environment has arguably propelled the Earth into its sixth mass extinction event and amphibians, the most threatened of all vertebrate taxa, are at the forefront. Many of the worldwide amphibian declines have been caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), and two contrasting hypotheses have been proposed to explain these declines. Positive correlations between global warming and Bd-related declines sparked the chytrid-thermal-optimum hypothesis, which proposes that global warming increased cloud cover in warm years that drove the convergence of daytime and nighttime temperatures toward the thermal optimum for Bd growth. In contrast, the spatiotemporal-spread hypothesis states that Bd-related declines are caused by the introduction and spread of Bd, independent of climate change. We provide a rigorous test of these hypotheses by evaluating (i) whether cloud cover, temperature convergence, and predicted temperature-dependent Bd growth are significant positive predictors of amphibian extinctions in the genus Atelopus and (ii) whether spatial structure in the timing of these extinctions can be detected without making assumptions about the location, timing, or number of Bd emergences. We show that there is spatial structure to the timing of Atelopus spp. extinctions but that the cause of this structure remains equivocal, emphasizing the need for further molecular characterization of Bd. We also show that the reported positive multi-decade correlation between Atelopus spp. extinctions and mean tropical air temperature in the previous year is indeed robust, but the evidence that it is causal is weak because numerous other variables, including regional banana and beer production, were better predictors of these extinctions. Finally, almost all of our findings were opposite to the predictions of the chytrid-thermal-optimum hypothesis. Although climate change is likely to play an important role in worldwide amphibian declines

Does physiological response to disease incur cost to reproductive ecology in a sexually dichromatic amphibian species?

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Kindermann, Christina; Narayan, Edward J; Hero, Jean-Marc

2017-01-01

It is well known that the disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) has contributed to amphibian declines worldwide. The impact of Bd varies, with some species being more susceptible to infection than others. Recent evidence has shown that Bd can have sub-lethal effects, whereby increases in stress hormones have been associated with infection. Could this increased stress response, which is a physiological adaptation that provides an increased resilience against Bd infection, potentially be a trade-off with important life-history traits such as reproduction? We studied this question in adult male frogs of a non-declining species (Litoria wilcoxii). Frogs were sampled for (1) seasonal hormone (testosterone and corticosterone), color and disease profiles, (2) the relationship between disease infection status and hormone levels or dorsal color, (3) subclinical effects of Bd by investigating disease load and hormone level, and (4) reproductive and stress hormone relationships independent of disease. Testosterone levels and color score varied seasonally (throughout the spring/summer months) while corticosterone levels remained stable. Frogs with high Bd prevalence had significantly higher corticosterone levels and lower testosterone levels compared to uninfected frogs, and no differences in color were observed. There was a significant positive correlation between disease load and corticosterone levels, and a significant negative relationship between disease load and testosterone. Our field data provides novel evidence that increased physiological stress response associated with Bd infection in wild frogs, could suppress reproduction by down-regulating gonadal hormones in amphibians, however the impacts on reproductive output is yet to be established. Copyright © 2016 Elsevier Inc. All rights reserved.

Trouble in the aquatic world: How wildlife professionals are battling amphibian declines

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Olson, Deanna H.; Chestnut, Tara E.

2014-01-01

A parasitic fungus, similar to the one that caused the extinction of numerous tropical frog and toad species, is killing salamanders in Europe. Scientists first identified the fungus, Batrachochytrium salamandrivorans, in 2013 as the culprit behind the death of fire salamanders (Salamandra salamandra) in the Netherlands (Martel et al. 2013) and are now exploring its potential impact to other species. Although the fungus, which kills the amphibians by infecting their skin, has not yet spread to the United States, researchers believe it’s only a matter of time before it does and, when that happens, the impact on salamander populations could be devastating (Martel et al. 2014).Reports of worldwide declines of amphibians began a quarter of a century ago (Blaustein & Wake 1990). Globally, some amphibian population declines occurred in the late 1950s and early 1960s, and declining trends continued in North America (Houlahan et al. 2000). In the earlier years, population declines were attributed primarily to overharvest due to unregulated supply of species such as the northern leopard frog (Lithobates pipiens) for educational use (Dodd 2013). In later years, however, causes of declines were less evident. In 1989, herpetologists at the First World Congress of Herpetology traded alarming stories of losses across continents and in seemingly protected landscapes, making it clear that amphibian population declines were a “global phenomenon.” In response to these reports, in 1991, the International Union for Conservation of Nature (IUCN) established the Declining Amphibian Populations Task Force to better understand the scale and scope of global amphibian declines. Unfortunately, the absence of long-term monitoring data and targeted studies made it difficult for the task force to compile information.Today, according to AmphibiaWeb.org, there are 7,342 amphibian species in the world — double the number since the first alerts of declines — making the situation

Diseases of amphibian eggs and embryos

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Green, D.E.; Converse, K.A.; Majumdar, S.K.; Huffman, J.E.; Brenner, F.J.; Panah, A.I.

2005-01-01

Amphibians generally are prolific egg producers. In tropical and semi-tropical regions, deposition of eggs may occur year-round or may coincide with rainy seasons, while in temperate regions, deposition of eggs usually occurs immediately after emergence from hibernation. Numbers of eggs produced by each species may vary from a few dozen to thousands. Accordingly, some eggs may be infertile and wastage of embryos is to be expected. Fertility, viability and decomposition of eggs and embryos must be considered before it is assumed that diseases are present. An important consideration in the evaluation of egg masses is the fact that some will contain infertile and non-viable eggs. These infertile and nonviable eggs will undergo decomposition and they may appear similar to eggs that are infected by a pathogen. Evaluation of egg masses and embryos for the presence of disease may require repeated observations in a given breeding season as well as continued monitoring of egg masses during their growth and development and over successive breeding seasons. Amphibian eggs rarely are subjected to a comprehensive health (diagnostic) examination; hence, there is scant literature on the diseases of this life stage. Indeed, the eggs of some North American amphibians have yet to be described. Much basic physiology and normal biomedical baseline data on amphibian eggs is lacking. For example, it is known that the aquatic eggs of some species of shrimp quickly are coated by a protective and commensal bacterium that effectively impedes invasion of the eggs by other environmental organisms and potential pathogens. In the absence of this bacterium, shrimp eggs are rapidly killed by other bacteria and fungi (Green, 2001). The possibility that amphibian eggs also have important symbiotic or commensal bacteria needs to be investigated. Furthermore, the quantity and types of chemicals in the normal gelatinous capsules of amphibian eggs have scarcely been examined. Abnormalities of the

Rapid extirpation of a North American frog coincides with an increase in fungal pathogen prevalence: Historical analysis and implications for reintroduction.

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Adams, Andrea J; Pessier, Allan P; Briggs, Cheryl J

2017-12-01

As extinctions continue across the globe, conservation biologists are turning to species reintroduction programs as one optimistic tool for addressing the biodiversity crisis. For repatriation to become a viable strategy, fundamental prerequisites include determining the causes of declines and assessing whether the causes persist in the environment. Invasive species-especially pathogens-are an increasingly significant factor contributing to biodiversity loss. We hypothesized that Batrachochytrium dendrobatidis (Bd), the causative agent of the deadly amphibian disease chytridiomycosis, was important in the rapid (herpetological experts, analysis of archived field notes and museum specimen collections, and field sampling of the extant amphibian assemblage to examine (1) historical relative abundance of R. boylii ; (2) potential causes of R. boylii declines; and (3) historical and contemporary prevalence of Bd. We found that R. boylii were relatively abundant prior to their rapid extirpation, and an increase in Bd prevalence coincided with R. boylii declines during a time of rapid change in the region, wherein backcountry recreation, urban development, and the amphibian pet trade were all on the rise. In addition, extreme flooding during the winter of 1969 coincided with localized extirpations in R. boylii populations observed by interview respondents. We conclude that Bd likely played an important role in the rapid extirpation of R. boylii from southern California and that multiple natural and anthropogenic factors may have worked in concert to make this possible in a relatively short period of time. This study emphasizes the importance of recognizing historical ecological contexts in making future management and reintroduction decisions.

Zoonotic diseases associated with reptiles and amphibians: an update.

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Mitchell, Mark A

2011-09-01

Reptiles and amphibians are popular as pets. There are increased concerns among public health officials because of the zoonotic potential associated with these animals. Encounters with reptiles and amphibians are also on the rise in the laboratory setting and with wild animals; in both of these practices, there is also an increased likelihood for exposure to zoonotic pathogens. It is important that veterinarians remain current with the literature as it relates to emerging and reemerging zoonotic diseases attributed to reptiles and amphibians so that they can protect themselves, their staff, and their clients from potential problems.

Direct and Indirect Effects of Climate Change on Amphibian Populations

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Stephanie S. Gervasi

2010-02-01

Full Text Available As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.

Effects of amphibian chytrid fungus on individual survival probability in wild boreal toads

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Pilliod, D.S.; Muths, E.; Scherer, R. D.; Bartelt, P.E.; Corn, P.S.; Hossack, B.R.; Lambert, B.A.; Mccaffery, R.; Gaughan, C.

2010-01-01

Chytridiomycosis is linked to the worldwide decline of amphibians, yet little is known about the demographic effects of the disease. We collected capture-recapture data on three populations of boreal toads (Bufo boreas [Bufo = Anaxyrus]) in the Rocky Mountains (U.S.A.). Two of the populations were infected with chytridiomycosis and one was not. We examined the effect of the presence of amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]; the agent of chytridiomycosis) on survival probability and population growth rate. Toads that were infected with Bd had lower average annual survival probability than uninfected individuals at sites where Bd was detected, which suggests chytridiomycosis may reduce survival by 31-42% in wild boreal toads. Toads that were negative for Bd at infected sites had survival probabilities comparable to toads at the uninfected site. Evidence that environmental covariates (particularly cold temperatures during the breeding season) influenced toad survival was weak. The number of individuals in diseased populations declined by 5-7%/year over the 6 years of the study, whereas the uninfected population had comparatively stable population growth. Our data suggest that the presence of Bd in these toad populations is not causing rapid population declines. Rather, chytridiomycosis appears to be functioning as a low-level, chronic disease whereby some infected individuals survive but the overall population effects are still negative. Our results show that some amphibian populations may be coexisting with Bd and highlight the importance of quantitative assessments of survival in diseased animal populations. Journal compilation. ?? 2010 Society for Conservation Biology. No claim to original US government works.

Are outbreaks of emerging pathogens correlated with construction of wetlands? Report 2 : amphibian breeding and disease outbreaks during 2014-2015 and possible correlates with environmental variables : research report.

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2016-10-01

A study of wetlands near the Intercounty Connector construction site (now a toll facility MD 200) in Maryland, : found that an emerging pathogen known as Ranavirus was having a significant impact on at least two species of : amphibians as well as...

75 FR 56975 - Injurious Wildlife Species; Review of Information Concerning a Petition To List All Live...

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2010-09-17

..., amphibians, and reptiles are the only organisms that can be added to the injurious wildlife list. The lists... Petition To List All Live Amphibians in Trade as Injurious Unless Free of Batrachochytrium dendrobatidis... Wildlife Service (Service), are reviewing a petition to list, under the Lacey Act, all live amphibians or...

Potential interactions among disease, pesticides, water quality and adjacent land cover in amphibian habitats in the United States.

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Battaglin, W A; Smalling, K L; Anderson, C; Calhoun, D; Chestnut, T; Muths, E

2016-10-01

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

Potential interactions among disease, pesticides, water quality and adjacent land cover in amphibian habitats in the United States

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Battaglin, William A.; Smalling, Kelly L.; Anderson, Chauncey; Calhoun, Daniel L.; Chestnut, Tara E.; Muths, Erin L.

2016-01-01

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

Epizootic to enzootic transition of a fungal disease in tropical Andean frogs: Are surviving species still susceptible?

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Alessandro Catenazzi

Full Text Available The fungal pathogen Batrachochytrium dendrobatidis (Bd, which causes the disease chytridiomycosis, has been linked to catastrophic amphibian declines throughout the world. Amphibians differ in their vulnerability to chytridiomycosis; some species experience epizootics followed by collapse while others exhibit stable host/pathogen dynamics where most amphibian hosts survive in the presence of Bd (e.g., in the enzootic state. Little is known about the factors that drive the transition between the two disease states within a community, or whether populations of species that survived the initial epizootic are stable, yet this information is essential for conservation and theory. Our study focuses on a diverse Peruvian amphibian community that experienced a Bd-caused collapse. We explore host/Bd dynamics of eight surviving species a decade after the mass extinction by using population level disease metrics and Bd-susceptibility trials. We found that three of the eight species continue to be susceptible to Bd, and that their populations are declining. Only one species is growing in numbers and it was non-susceptible in our trials. Our study suggests that some species remain vulnerable to Bd and exhibit ongoing population declines in enzootic systems where Bd-host dynamics are assumed to be stable.

Field evidence for leech-borne transmission of amphibian Ichthyophonus sp.

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Raffel, Thomas R; Dillard, James R; Hudson, Peter J

2006-12-01

Parasites have been implicated in mass mortality events and population declines of amphibians around the world. One pathogen associated with mortality events in North America is an Ichthyophonus sp.-like organism that affects red-spotted newts (Notophthalmus viridescens) and several frog species, yet little is known about the distribution of this pathogen in wild populations or the mechanism of transmission. In an effort to identify factors influencing the distribution and abundance of this pathogen, we measured Ichthyophonus sp. prevalence and a series of factors that could contribute to transmission in 16 newt populations during spring 2004. In contrast to our initial hypotheses of trophic transmission, several lines of evidence suggested a role for the amphibian leech (Placobdella picta) in Ichthyophonus sp. transmission. We propose the mechanistic hypothesis that a leech acquires Ichthyophonus sp. infection when inserting its proboscis into the muscles beneath the skin of infected newts and transmits the infection to other newts in subsequent feeding bouts. We also found effects of host sex, body mass, and breeding condition on Ichthyophonus sp. prevalence and the number of attached leeches. The number of leeches attached to newts was strongly related to the proportion of newt habitat containing emergent vegetation, suggesting that anthropogenic eutrophication might lead to more frequent or severe outbreaks of Ichthyophonus sp. infection in amphibians.

Ecophysiology meets conservation: understanding the role of disease in amphibian population declines

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Blaustein, Andrew R.; Gervasi, Stephanie S.; Johnson, Pieter T. J.; Hoverman, Jason T.; Belden, Lisa K.; Bradley, Paul W.; Xie, Gisselle Y.

2012-01-01

Infectious diseases are intimately associated with the dynamics of biodiversity. However, the role that infectious disease plays within ecological communities is complex. The complex effects of infectious disease at the scale of communities and ecosystems are driven by the interaction between host and pathogen. Whether or not a given host–pathogen interaction results in progression from infection to disease is largely dependent on the physiological characteristics of the host within the context of the external environment. Here, we highlight the importance of understanding the outcome of infection and disease in the context of host ecophysiology using amphibians as a model system. Amphibians are ideal for such a discussion because many of their populations are experiencing declines and extinctions, with disease as an important factor implicated in many declines and extinctions. Exposure to pathogens and the host's responses to infection can be influenced by many factors related to physiology such as host life history, immunology, endocrinology, resource acquisition, behaviour and changing climates. In our review, we discuss the relationship between disease and biodiversity. We highlight the dynamics of three amphibian host–pathogen systems that induce different effects on hosts and life stages and illustrate the complexity of amphibian–host–parasite systems. We then review links between environmental stress, endocrine–immune interactions, disease and climate change. PMID:22566676

Antibacterial therapeutics for the treatment of chytrid infection in amphibians: Columbus's egg?

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Muijsers, Mariska; Martel, An; Van Rooij, Pascale; Baert, Kris; Vercauteren, Griet; Ducatelle, Richard; De Backer, Patrick; Vercammen, Francis; Haesebrouck, Freddy; Pasmans, Frank

2012-09-25

The establishment of safe and effective protocols to treat chytridiomycosis in amphibians is urgently required. In this study, the usefulness of antibacterial agents to clear chytridiomycosis from infected amphibians was evaluated. Florfenicol, sulfamethoxazole, sulfadiazine and the combination of trimethoprim and sulfonamides were active in vitro against cultures of five Batrachochytrium dendrobatidis strains containing sporangia and zoospores, with minimum inhibitory concentrations (MIC) of 0.5-1.0 μg/ml for florfenicol and 8.0 μg/ml for the sulfonamides. Trimethoprim was not capable of inhibiting growth but, combined with sulfonamides, reduced the time to visible growth inhibition by the sulfonamides. Growth inhibition of B. dendrobatidis was not observed after exposure to clindamycin, doxycycline, enrofloxacin, paromomycin, polymyxin E and tylosin. Cultures of sporangia and zoospores of B. dendrobatidis strains JEL423 and IA042 were killed completely after 14 days of exposure to 100 μg/ml florfenicol or 16 μg/ml trimethoprim combined with 80 μg/ml sulfadiazine. These concentrations were, however, not capable of efficiently killing zoospores within 4 days after exposure as assessed using flow cytometry. Florfenicol concentrations remained stable in a bathing solution during a ten day period. Exposure of Discoglossus scovazzi tadpoles for ten days to 100 μg/ml but not to 10 μg florfenicol /ml water resulted in toxicity. In an in vivo trial, post metamorphic Alytes muletensis, experimentally inoculated with B. dendrobatidis, were treated topically with a solution containing 10 μg/ml of florfenicol during 14 days. Although a significant reduction of the B. dendrobatidis load was obtained, none of the treated animals cleared the infection. We thus conclude that, despite marked anti B. dendrobatidis activity in vitro, the florfenicol treatment used is not capable of eliminating B. dendrobatidis infections from amphibians.

Using a Bayesian network to clarify areas requiring research in a host-pathogen system.

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Bower, D S; Mengersen, K; Alford, R A; Schwarzkopf, L

2017-12-01

Bayesian network analyses can be used to interactively change the strength of effect of variables in a model to explore complex relationships in new ways. In doing so, they allow one to identify influential nodes that are not well studied empirically so that future research can be prioritized. We identified relationships in host and pathogen biology to examine disease-driven declines of amphibians associated with amphibian chytrid fungus (Batrachochytrium dendrobatidis). We constructed a Bayesian network consisting of behavioral, genetic, physiological, and environmental variables that influence disease and used them to predict host population trends. We varied the impacts of specific variables in the model to reveal factors with the most influence on host population trend. The behavior of the nodes (the way in which the variables probabilistically responded to changes in states of the parents, which are the nodes or variables that directly influenced them in the graphical model) was consistent with published results. The frog population had a 49% probability of decline when all states were set at their original values, and this probability increased when body temperatures were cold, the immune system was not suppressing infection, and the ambient environment was conducive to growth of B. dendrobatidis. These findings suggest the construction of our model reflected the complex relationships characteristic of host-pathogen interactions. Changes to climatic variables alone did not strongly influence the probability of population decline, which suggests that climate interacts with other factors such as the capacity of the frog immune system to suppress disease. Changes to the adaptive immune system and disease reservoirs had a large effect on the population trend, but there was little empirical information available for model construction. Our model inputs can be used as a base to examine other systems, and our results show that such analyses are useful tools for

Widespread Elevational Occurrence of Antifungal Bacteria in Andean Amphibians Decimated by Disease: A Complex Role for Skin Symbionts in Defense Against Chytridiomycosis.

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Catenazzi, Alessandro; Flechas, Sandra V; Burkart, David; Hooven, Nathan D; Townsend, Joseph; Vredenburg, Vance T

2018-01-01

Emerging infectious disease is a growing threat to global health, and recent discoveries reveal that the microbiota dwelling on and within hosts can play an important role in health and disease. To understand the capacity of skin bacteria to protect amphibian hosts from the fungal disease chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd), we isolated 192 bacterial morphotypes from the skin of 28 host species of frogs (families Bufonidae, Centrolenidae, Hemiphractidae, Hylidae, Leptodactylidae, Strabomantidae, and Telmatobiidae) collected from the eastern slopes of the Peruvian Andes (540-3,865 m a.s.l.) in the Kosñipata Valley near Manu National Park, a site where we previously documented the collapse of montane frog communities following chytridiomycosis epizootics. We obtained isolates through agar culture from skin swabs of wild frogs, and identified bacterial isolates by comparing 16S rRNA sequences against the GenBank database using BLAST. We identified 178 bacterial strains of 38 genera, including 59 bacterial species not previously reported from any amphibian host. The most common bacterial isolates were species of Pseudomonas, Paenibacillus, Chryseobacterium, Comamonas, Sphingobacterium , and Stenotrophomonas . We assayed the anti-fungal abilities of 133 bacterial isolates from 26 frog species. To test whether cutaneous bacteria might inhibit growth of the fungal pathogen, we used a local Bd strain isolated from the mouthparts of stream-dwelling tadpoles ( Hypsiboas gladiator , Hylidae). We quantified Bd-inhibition in vitro with co-culture assays. We found 20 bacterial isolates that inhibited Bd growth, including three isolates not previously known for such inhibitory abilities. Anti-Bd isolates occurred on aquatic and terrestrial breeding frogs across a wide range of elevations (560-3,695 m a.s.l.). The inhibitory ability of anti-Bd isolates varied considerably. The proportion of anti-Bd isolates was lowest at mid-elevations (6%), where

Widespread Elevational Occurrence of Antifungal Bacteria in Andean Amphibians Decimated by Disease: A Complex Role for Skin Symbionts in Defense Against Chytridiomycosis

Directory of Open Access Journals (Sweden)

Alessandro Catenazzi

2018-03-01

Full Text Available Emerging infectious disease is a growing threat to global health, and recent discoveries reveal that the microbiota dwelling on and within hosts can play an important role in health and disease. To understand the capacity of skin bacteria to protect amphibian hosts from the fungal disease chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd, we isolated 192 bacterial morphotypes from the skin of 28 host species of frogs (families Bufonidae, Centrolenidae, Hemiphractidae, Hylidae, Leptodactylidae, Strabomantidae, and Telmatobiidae collected from the eastern slopes of the Peruvian Andes (540–3,865 m a.s.l. in the Kosñipata Valley near Manu National Park, a site where we previously documented the collapse of montane frog communities following chytridiomycosis epizootics. We obtained isolates through agar culture from skin swabs of wild frogs, and identified bacterial isolates by comparing 16S rRNA sequences against the GenBank database using BLAST. We identified 178 bacterial strains of 38 genera, including 59 bacterial species not previously reported from any amphibian host. The most common bacterial isolates were species of Pseudomonas, Paenibacillus, Chryseobacterium, Comamonas, Sphingobacterium, and Stenotrophomonas. We assayed the anti-fungal abilities of 133 bacterial isolates from 26 frog species. To test whether cutaneous bacteria might inhibit growth of the fungal pathogen, we used a local Bd strain isolated from the mouthparts of stream-dwelling tadpoles (Hypsiboas gladiator, Hylidae. We quantified Bd-inhibition in vitro with co-culture assays. We found 20 bacterial isolates that inhibited Bd growth, including three isolates not previously known for such inhibitory abilities. Anti-Bd isolates occurred on aquatic and terrestrial breeding frogs across a wide range of elevations (560–3,695 m a.s.l.. The inhibitory ability of anti-Bd isolates varied considerably. The proportion of anti-Bd isolates was lowest at mid-elevations (6

West Africa - A Safe Haven for Frogs? A Sub-Continental Assessment of the Chytrid Fungus (Batrachochytrium dendrobatidis)

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Penner, Johannes; Adum, Gilbert B.; McElroy, Matthew T.; Doherty-Bone, Thomas; Hirschfeld, Mareike; Sandberger, Laura; Weldon, Ché; Cunningham, Andrew A.; Ohst, Torsten; Wombwell, Emma; Portik, Daniel M.; Reid, Duncan; Hillers, Annika; Ofori-Boateng, Caleb; Oduro, William; Plötner, Jörg; Ohler, Annemarie; Leaché, Adam D.; Rödel, Mark-Oliver

2013-01-01

A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd). While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species) for the presence of Bd. The samples originated from seven West African countries - Bénin, Burkina Faso, Côte d'Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds) environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni (“Vulnerable”) and Petropedetes natator (“Near Threatened”)) as well as the “Critically Endangered” viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis). PMID:23426141

West Africa - a safe haven for frogs? A sub-continental assessment of the chytrid fungus (Batrachochytrium dendrobatidis.

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Johannes Penner

Full Text Available A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd. While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species for the presence of Bd. The samples originated from seven West African countries - Bénin, Burkina Faso, Côte d'Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni ("Vulnerable" and Petropedetes natator ("Near Threatened" as well as the "Critically Endangered" viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis.

Over-wintering tadpoles of Mixophyes fasciolatus act as reservoir host for Batrachochytrium dendrobatidis.

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Edward J Narayan

Full Text Available Batrachochytrium dendrobatidis (Bd, a cutaneous amphibian fungus that causes the lethal disease chytridiomycosis, has been implicated as a cause of many amphibian declines. Bd can tolerate low temperatures with an optimum thermal range from 17-24°C. It has been shown that Bd infection may result in species extinction, avoiding the transmission threshold presented by density dependent transmission theory. Prevalence of Bd during autumn and winter has been shown to be as low as 0% in some species. It is currently unclear how Bd persists in field conditions and what processes result in carry-over between seasons. It has been hypothesised that overwintering tadpoles may host Bd between breeding seasons. The Great Barred Frog (Mixophyes fasciolatus is a common, stable and widespread species in Queensland, Australia, and is known to carry Bd. Investigation into Bd infection of different life stages of M. fasciolatus during seasonally low prevalence may potentially reveal persistence and carry-over methods between seasons. Metamorphs, juveniles, and adults were swabbed for Bd infection over three months (between March and May, 2011 at 5 sites of varying altitude (66 m-790 m. A total of 93 swabs were analysed using Polymerase Chain Reaction (PCR real-time analysis. PCR analysis showed 6 positive (1 excluded, 4 equivocal and 83 negative results for infection with Bd. Equivocal results were assumed to be negative using the precautionary principle. The 5 positive results consisted of 4 emerging (Gosner stage 43-45 metamorphs and 1 adult M. fasciolatus. Fisher's exact test on prevalence showed that the prevalence was significantly different between life stages. All positive results were sampled at high altitudes (790 m; however prevalence was not significantly different between altitudes. Infection of emerging metamorphs suggests that individuals were infected as tadpoles. We hypothesise that M. fasciolatus tadpoles carry Bd through seasons. Thus

Antibacterial therapeutics for the treatment of chytrid infection in amphibians: Columbus’s egg?

Science.gov (United States)

2012-01-01

Background The establishment of safe and effective protocols to treat chytridiomycosis in amphibians is urgently required. In this study, the usefulness of antibacterial agents to clear chytridiomycosis from infected amphibians was evaluated. Results Florfenicol, sulfamethoxazole, sulfadiazine and the combination of trimethoprim and sulfonamides were active in vitro against cultures of five Batrachochytrium dendrobatidis strains containing sporangia and zoospores, with minimum inhibitory concentrations (MIC) of 0.5-1.0 μg/ml for florfenicol and 8.0 μg/ml for the sulfonamides. Trimethoprim was not capable of inhibiting growth but, combined with sulfonamides, reduced the time to visible growth inhibition by the sulfonamides. Growth inhibition of B. dendrobatidis was not observed after exposure to clindamycin, doxycycline, enrofloxacin, paromomycin, polymyxin E and tylosin. Cultures of sporangia and zoospores of B. dendrobatidis strains JEL423 and IA042 were killed completely after 14 days of exposure to 100 μg/ml florfenicol or 16 μg/ml trimethoprim combined with 80 μg/ml sulfadiazine. These concentrations were, however, not capable of efficiently killing zoospores within 4 days after exposure as assessed using flow cytometry. Florfenicol concentrations remained stable in a bathing solution during a ten day period. Exposure of Discoglossus scovazzi tadpoles for ten days to 100 μg/ml but not to 10 μg florfenicol /ml water resulted in toxicity. In an in vivo trial, post metamorphic Alytes muletensis, experimentally inoculated with B. dendrobatidis, were treated topically with a solution containing 10 μg/ml of florfenicol during 14 days. Although a significant reduction of the B. dendrobatidis load was obtained, none of the treated animals cleared the infection. Conclusions We thus conclude that, despite marked anti B. dendrobatidis activity in vitro, the florfenicol treatment used is not capable of eliminating B. dendrobatidis infections

Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan.

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Andoh, Masako; Sakata, Akiko; Takano, Ai; Kawabata, Hiroki; Fujita, Hiromi; Une, Yumi; Goka, Koichi; Kishimoto, Toshio; Ando, Shuji

2015-01-01

One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the presence of Rickettsia and Ehrlichia spp. genes in ticks associated with reptiles and amphibians originating from outside Japan. Ninety-three ticks representing nine tick species (genera Amblyomma and Hyalomma) were isolated from at least 28 animals spanning 10 species and originating from 12 countries (Ghana, Jordan, Madagascar, Panama, Russia, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Uzbekistan, and Zambia). None of the nine tick species are indigenous in Japan. The genes encoding the common rickettsial 17-kDa antigen, citrate synthase (gltA), and outer membrane protein A (ompA) were positively detected in 45.2% (42/93), 40.9% (38/93), and 23.7% (22/93) of the ticks, respectively, by polymerase chain reaction (PCR). The genes encoding ehrlichial heat shock protein (groEL) and major outer membrane protein (omp-1) were PCR-positive in 7.5% (7/93) and 2.2% (2/93) of the ticks, respectively. The p44 gene, which encodes the Anaplasma outer membrane protein, was not detected. Phylogenetic analysis showed that several of the rickettsial and ehrlichial sequences isolated in this study were highly similar to human pathogen genes, including agents not previously detected in Japan. These data demonstrate the global transportation of pathogenic Rickettsia and Ehrlichia through reptile- and amphibian-associated ticks. These imported animals have potential to transfer pathogens into human life. These results highlight the need to control the international transportation of known and

Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan.

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Masako Andoh

Full Text Available One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the presence of Rickettsia and Ehrlichia spp. genes in ticks associated with reptiles and amphibians originating from outside Japan. Ninety-three ticks representing nine tick species (genera Amblyomma and Hyalomma were isolated from at least 28 animals spanning 10 species and originating from 12 countries (Ghana, Jordan, Madagascar, Panama, Russia, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Uzbekistan, and Zambia. None of the nine tick species are indigenous in Japan. The genes encoding the common rickettsial 17-kDa antigen, citrate synthase (gltA, and outer membrane protein A (ompA were positively detected in 45.2% (42/93, 40.9% (38/93, and 23.7% (22/93 of the ticks, respectively, by polymerase chain reaction (PCR. The genes encoding ehrlichial heat shock protein (groEL and major outer membrane protein (omp-1 were PCR-positive in 7.5% (7/93 and 2.2% (2/93 of the ticks, respectively. The p44 gene, which encodes the Anaplasma outer membrane protein, was not detected. Phylogenetic analysis showed that several of the rickettsial and ehrlichial sequences isolated in this study were highly similar to human pathogen genes, including agents not previously detected in Japan. These data demonstrate the global transportation of pathogenic Rickettsia and Ehrlichia through reptile- and amphibian-associated ticks. These imported animals have potential to transfer pathogens into human life. These results highlight the need to control the international transportation of known

Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar

OpenAIRE

Bletz, Molly C.; Archer, Holly; Harris, Reid N.; McKenzie, Valerie J.; Rabemananjara, Falitiana C. E.; Rakotoarison, Andolalao; Vences, Miguel

2017-01-01

Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Usin...

Microevolution due to pollution in amphibians: A review on the genetic erosion hypothesis

International Nuclear Information System (INIS)

Fasola, E.; Ribeiro, R.; Lopes, I.

2015-01-01

The loss of genetic diversity, due to exposure to chemical contamination (genetic erosion), is a major threat to population viability. Genetic erosion is the loss of genetic variation: the loss of alleles determining the value of a specific trait or set of traits. Almost a third of the known amphibian species is considered to be endangered and a decrease of genetic variability can push them to the verge of extinction. This review indicates that loss of genetic variation due to chemical contamination has effects on: 1) fitness, 2) environmental plasticity, 3) co-tolerance mechanisms, 4) trade-off mechanisms, and 5) tolerance to pathogens in amphibian populations. - Highlights: • Effects of environmental stressors on the genetic diversity of natural populations of amphibians have usually been underestimated. • Environmental pollution may reduce the genetic diversity of exposed amphibian populations. • Genetic erosion can lead to reduced fitness and lack of adaptability to a changing environment. - Contaminant-driven genetic erosion is a major threat to population viability in amphibians

The link between rapid enigmatic amphibian decline and the globally emerging chytrid fungus.

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Lötters, Stefan; Kielgast, Jos; Bielby, Jon; Schmidtlein, Sebastian; Bosch, Jaime; Veith, Michael; Walker, Susan F; Fisher, Matthew C; Rödder, Dennis

2009-09-01

Amphibians are globally declining and approximately one-third of all species are threatened with extinction. Some of the most severe declines have occurred suddenly and for unknown reasons in apparently pristine habitats. It has been hypothesized that these "rapid enigmatic declines" are the result of a panzootic of the disease chytridiomycosis caused by globally emerging amphibian chytrid fungus. In a Species Distribution Model, we identified the potential distribution of this pathogen. Areas and species from which rapid enigmatic decline are known significantly overlap with those of highest environmental suitability to the chytrid fungus. We confirm the plausibility of a link between rapid enigmatic decline in worldwide amphibian species and epizootic chytridiomycosis.

Cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.

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Joshua H Daskin

Full Text Available Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd, is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians' skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd's optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata. All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8 °C to 33 °C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to

Cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.

Science.gov (United States)

Daskin, Joshua H; Bell, Sara C; Schwarzkopf, Lin; Alford, Ross A

2014-01-01

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians' skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd's optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata). All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8 °C to 33 °C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs) from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to avoid

Inhibition of Caused by Bacteria Isolated from the Skin of Boreal Toads, , from Grand Teton National Park, Wyoming, USA

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Shawna T. Park

2014-01-01

Full Text Available The chytrid fungus Batrachochytrium dendrobatidis is a significant cause of the worldwide decline in amphibian populations; however, various amphibian species are capable of coexisting with B. dendrobatidis. Among them are boreal toads ( Anaxyrus ( Bufo boreas boreas located in Grand Teton National Park (GTNP in Wyoming, USA. The purpose of this study was to identify cultivable bacterial isolates from the skin microbiota of boreal toads from GTNP and determine if they were capable of inhibiting B. dendrobatidis in vitro, and therefore might be a factor in the toad's coexistence with this pathogen. Isolates from 6 of 21 genera tested were found to inhibit the growth of B. dendrobatidis. These bacteria represent diverse lineages such as the Gammaproteobacteria, the Betaproteobacteria, and the Bacteroidetes/Chlorobium groups. We propose that these bacteria compete via microbial antagonism with B. dendrobatidis.

Amphibians at risk? Susceptibility of terrestrial amphibian life stages to pesticides.

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Brühl, Carsten A; Pieper, Silvia; Weber, Brigitte

2011-11-01

Current pesticide risk assessment does not specifically consider amphibians. Amphibians in the aquatic environment (aquatic life stages or postmetamorphic aquatic amphibians) and terrestrial living juvenile or adult amphibians are assumed to be covered by the risk assessment for aquatic invertebrates and fish, or mammals and birds, respectively. This procedure has been evaluated as being sufficiently protective regarding the acute risk posed by a number of pesticides to aquatic amphibian life stages (eggs, larvae). However, it is unknown whether the exposure and sensitivity of terrestrial living amphibians are comparable to mammalian and avian exposure and sensitivity. We reviewed the literature on dermal pesticide absorption and toxicity studies for terrestrial life stages of amphibians, focusing on the dermal exposure pathway, that is, through treated soil or direct overspray. In vitro studies demonstrated that cutaneous absorption of chemicals is significant and that chemical percutaneous passage, P (cm/h), is higher in amphibians than in mammals. In vivo, the rapid and substantial uptake of the herbicide atrazine from treated soil by toads (Bufo americanus) has been described. Severe toxic effects on various amphibian species have been reported for field-relevant application rates of different pesticides. In general, exposure and toxicity studies for terrestrial amphibian life stages are scarce, and the reported data indicate the need for further research, especially in light of the global amphibian decline. Copyright © 2011 SETAC.

Global Amphibian Extinction Risk Assessment for the Panzootic Chytrid Fungus

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Matthew C. Fisher

2009-09-01

Full Text Available Species are being lost at increasing rates due to anthropogenic effects, leading to the recognition that we are witnessing the onset of a sixth mass extinction. Emerging infectious disease has been shown to increase species loss and any attempts to reduce extinction rates need to squarely confront this challenge. Here, we develop a procedure for identifying amphibian species that are most at risk from the effects of chytridiomycosis by combining spatial analyses of key host life-history variables with the pathogen's predicted distribution. We apply our rule set to the known global diversity of amphibians in order to prioritize pecies that are most at risk of loss from disease emergence. This risk assessment shows where limited conservation funds are best deployed in order to prevent further loss of species by enabling ex situ amphibian salvage operations and focusing any potential disease mitigation projects.

Antibacterial therapeutics for the treatment of chytrid infection in amphibians: Columbus’s egg?

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Muijsers Mariska

2012-09-01

Full Text Available Abstract Background The establishment of safe and effective protocols to treat chytridiomycosis in amphibians is urgently required. In this study, the usefulness of antibacterial agents to clear chytridiomycosis from infected amphibians was evaluated. Results Florfenicol, sulfamethoxazole, sulfadiazine and the combination of trimethoprim and sulfonamides were active in vitro against cultures of five Batrachochytrium dendrobatidis strains containing sporangia and zoospores, with minimum inhibitory concentrations (MIC of 0.5-1.0 μg/ml for florfenicol and 8.0 μg/ml for the sulfonamides. Trimethoprim was not capable of inhibiting growth but, combined with sulfonamides, reduced the time to visible growth inhibition by the sulfonamides. Growth inhibition of B. dendrobatidis was not observed after exposure to clindamycin, doxycycline, enrofloxacin, paromomycin, polymyxin E and tylosin. Cultures of sporangia and zoospores of B. dendrobatidis strains JEL423 and IA042 were killed completely after 14 days of exposure to 100 μg/ml florfenicol or 16 μg/ml trimethoprim combined with 80 μg/ml sulfadiazine. These concentrations were, however, not capable of efficiently killing zoospores within 4 days after exposure as assessed using flow cytometry. Florfenicol concentrations remained stable in a bathing solution during a ten day period. Exposure of Discoglossus scovazzi tadpoles for ten days to 100 μg/ml but not to 10 μg florfenicol /ml water resulted in toxicity. In an in vivo trial, post metamorphic Alytes muletensis, experimentally inoculated with B. dendrobatidis, were treated topically with a solution containing 10 μg/ml of florfenicol during 14 days. Although a significant reduction of the B. dendrobatidis load was obtained, none of the treated animals cleared the infection. Conclusions We thus conclude that, despite marked anti B. dendrobatidis activity in vitro, the florfenicol treatment used is not capable of eliminating B

Concurrent ranavirus and Batrachochytrium dendrobatidis infection in captive frogs (Phyllobates and Dendrobates species), The Netherlands, 2012: a first report.

Science.gov (United States)

Kik, Marja; Stege, Marisca; Boonyarittichaikij, Roschong; van Asten, Alphons

2012-11-01

A ranavirus infection with concurrent Batrachochytrium dendrobatidis infection and mortality in captive Phyllobates and Dendrobates species is reported. Greyish skin with hepato- and reno-megaly were evident. Microscopically, Batrachochytrium dendrobatidis was present in the stratum corneum of the hyperkeratotic skin. Intracytoplasmic inclusion bodies were present in erythrocytes and multiple organs. All samples examined tested positive using PCR for the major capsid protein (MCP) gene of ranavirus and the ITS-1-5.8S region of B. dendrobatidis. The sequence obtained showed a 99% identity with the deposited sequence of the MCP gene of the common midwife toad virus (CMTV). This is the first report of mortality in captivity in poison dart frogs caused by a ranavirus, CMTV or like virus, and Batrachochytrium dendrobatidis infection. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Search for Violacein-Producing Microbes to Combat Batrachochytrium dendrobatidis: A Collaborative Research Project between Secondary School and College Research Students

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Larra Agate

2015-10-01

Full Text Available In this citizen science–aided, college laboratory–based microbiology research project, secondary school students collaborate with college research students on an investigation centered around bacterial species in the local watershed. This study specifically investigated the prevalence of violacein-producing bacterial isolates, as violacein has been demonstrated as a potential bioremediation treatment for outbreaks of the worldwide invasive chytrid, Batrachochytrium dendrobatidis (Bd. The impact of this invasion has been linked to widespread amphibian decline, and tracking of the spread of Bd is currently ongoing. Secondary school students participated in this research project by sterilely collecting water samples from a local watershed, documenting the samples, and completing the initial sample plating in a BSL1 environment. In the second phase of this project, trained college students working in courses and as research assistants in the academic year and summer term in a BSL2 laboratory facility were able to use physiological, biochemical, and molecular techniques to further identify individual isolates as well as characterize their properties. Collaboration between these learning spaces provides an increased interest in the community for environmentally relevant research projects and allows for an expansion of the research team to increase study robustness.

Toward immunogenetic studies of amphibian chytridiomycosis: Linking innate and acquired immunity

Science.gov (United States)

Richmond, J.Q.; Savage, Anna E.; Zamudio, Kelly R.; Rosenblum, E.B.

2009-01-01

Recent declines in amphibian diversity and abundance have contributed significantly to the global loss of biodiversity. The fungal disease chytridiomycosis is widely considered to be a primary cause of these declines, yet the critical question of why amphibian species differ in susceptibility remains unanswered. Considerable evidence links environmental conditions and interspecific variability of the innate immune system to differential infection responses, but other sources of individual, population, or species-typical variation may also be important. In this article we review the preliminary evidence supporting a role for acquired immune defenses against chytridiomycosis, and advocate for targeted investigation of genes controlling acquired responses, as well as those that functionally bridge the innate and acquired immune systems. Immunogenetic data promise to answer key questions about chytridiomycosis susceptibility and host-pathogen coevolution, and will draw much needed attention to the importance of considering evolutionary processes in amphibian conservation management and practice. ?? 2009 by American Institute of Biological Sciences.

No evidence for effects of infection with the amphibian chytrid fungus on populations of yellow-bellied toads.

Science.gov (United States)

Wagner, Norman; Neubeck, Claus; Guicking, Daniela; Finke, Lennart; Wittich, Martin; Weising, Kurt; Geske, Christian; Veith, Michael

2017-02-08

The parasitic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause the lethal disease chytridiomycosis in amphibians and therefore may play a role in population declines. The yellow-bellied toad Bombina variegata suffered strong declines throughout western and northwestern parts of its range and is therefore listed as highly endangered for Germany and the federal state of Hesse. Whether chytridiomycosis may play a role in the observed local declines of this strictly protected anuran species has never been tested. We investigated 19 Hessian yellow-bellied toad populations for Bd infection rates, conducted capture-mark-recapture studies in 4 of them over 2 to 3 yr, examined survival histories of recaptured infected individuals, and tested whether multi-locus heterozygosity of individuals as well as expected heterozygosity and different environmental variables of populations affect probabilities of Bd infection. Our results show high prevalence of Bd infection in Hessian yellow-bellied toad populations, but although significant decreases in 2 populations could be observed, no causative link to Bd as the reason for this can be established. Mass mortalities or obvious signs of disease in individuals were not observed. Conversely, we show that growth of Bd-infected populations is possible under favorable habitat conditions and that most infected individuals could be recaptured with improved body indices. Neither genetic diversity nor environmental variables appeared to affect Bd infection probabilities. Hence, genetically diverse amphibian specimens and populations may not automatically be less susceptible for Bd infection.

First record of chytridiomycosis in Bolivia (Rhinella quechua; Anura: Bufonidae).

Science.gov (United States)

Barrionuevo, J Sebastián; Aguayo, Rodrigo; Lavilla, Esteban O

2008-11-20

The finding of tadpoles of Rhinella quechua (Huayramayu River, Carrasco National Park, Cochabamba, Bolivia) with oral abnormalities caused by Batrachochytrium dendrobatidis constitutes the first record of this fungal infection reported for Bolivian amphibians.

Sex Reversal in Amphibians.

Science.gov (United States)

Flament, Stéphane

2016-01-01

Amphibians have been widely used to study developmental biology due to the fact that embryo development takes place independently of the maternal organism and that observations and experimental approaches are easy. Some amphibians like Xenopus became model organisms in this field. In the first part of this article, the differentiation of the gonads in amphibians and the mechanisms governing this process are reviewed. In the second part, the state of the art about sex reversal, which can be induced by steroid hormones in general and by temperature in some species, is presented. Also information about pollutants found in the environment that could interfere with the development of the amphibian reproductive apparatus or with their reproductive physiology is given. Such compounds could play a part in the amphibian decline, since in the wild, many amphibians are endangered species. © 2016 S. Karger AG, Basel.

Micro-Eukaryote Diversity in Freshwater Ponds That Harbor the Amphibian Pathogen "Batrachochytrium Dendrobatidis" ("Bd")

Science.gov (United States)

Lauer, Antje; McConnel, Lonnie; Singh, Navdeep

2012-01-01

We designed a microbiology project that fully engaged undergraduate biology students, high school students, and their teachers in a summer research program as part of the Research Education Vitalizing Science University Program conducted at California State University Bakersfield. Modern molecular biological methods and microscopy were used to…

Antifungal Bacteria on Woodland Salamander Skin Exhibit High Taxonomic Diversity and Geographic Variability.

Science.gov (United States)

Muletz-Wolz, Carly R; DiRenzo, Graziella V; Yarwood, Stephanie A; Campbell Grant, Evan H; Fleischer, Robert C; Lips, Karen R

2017-05-01

Diverse bacteria inhabit amphibian skin; some of those bacteria inhibit growth of the fungal pathogen Batrachochytrium dendrobatidis Yet there has been no systematic survey of anti- B. dendrobatidis bacteria across localities, species, and elevations. This is important given geographic and taxonomic variations in amphibian susceptibility to B. dendrobatidis Our collection sites were at locations within the Appalachian Mountains where previous sampling had indicated low B. dendrobatidis prevalence. We determined the numbers and identities of anti- B. dendrobatidis bacteria on 61 Plethodon salamanders (37 P. cinereus , 15 P. glutinosus , 9 P. cylindraceus ) via culturing methods and 16S rRNA gene sequencing. We sampled co-occurring species at three localities and sampled P. cinereus along an elevational gradient (700 to 1,000 meters above sea level [masl]) at one locality. We identified 50 anti- B. dendrobatidis bacterial operational taxonomic units (OTUs) and found that the degree of B. dendrobatidis inhibition was not correlated with relatedness. Five anti- B. dendrobatidis bacterial strains occurred on multiple amphibian species at multiple localities, but none were shared among all species and localities. The prevalence of anti- B. dendrobatidis bacteria was higher at Shenandoah National Park (NP), VA, with 96% (25/26) of salamanders hosting at least one anti- B. dendrobatidis bacterial species compared to 50% (7/14) at Catoctin Mountain Park (MP), MD, and 38% (8/21) at Mt. Rogers National Recreation Area (NRA), VA. At the individual level, salamanders at Shenandoah NP had more anti- B. dendrobatidis bacteria per individual (μ = 3.3) than those at Catoctin MP (μ = 0.8) and at Mt. Rogers NRA (μ = 0.4). All salamanders tested negative for B. dendrobatidis Anti- B. dendrobatidis bacterial species are diverse in central Appalachian Plethodon salamanders, and their distribution varied geographically. The antifungal bacterial species that we identified may play a

Climate change and amphibians

Science.gov (United States)

Corn, P.S.

2005-01-01

Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines in Central America to climate relies solely on correlations, and the mechanisms underlying the declines are not understood. Connections between embryo mortality and declines in abundance have not been demonstrated. Analyses of existing data have generally failed to find a link between climate and amphibian declines. It is likely, however, that future climate change will cause further declines of some amphibian species. Reduced soil moisture could reduce prey species and eliminate habitat. Reduced snowfall and increased summer evaporation could have dramatic effects on the duration or occurrence of seasonal wetlands, which are primary habitat for many species of amphibians. Climate change may be a relatively minor cause of current amphibian declines, but it may be the biggest future challenge to the persistence of many species

Climate change and amphibians

Directory of Open Access Journals (Sweden)

Corn, P. S.

2005-01-01

Full Text Available Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines in Central America to climate relies solely on correlations, and the mechanisms underlying the declines are not understood. Connections between embryo mortality and declines in abundance have not been demonstrated. Analyses of existing data have generally failed to find a link between climate and amphibian declines. It is likely, however, that future climate change will cause further declines of some amphibian species. Reduced soil moisture could reduce prey species and eliminate habitat. Reduced snowfall and increased summer evaporation could have dramatic effects on the duration or occurrence of seasonal wetlands, which are primary habitat for many species of amphibians. Climate change may be a relatively minor cause of current amphibian declines, but it may be the biggest future challenge to the persistence of many species

Amphibians of Olympic National Park

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,

2000-01-01

Amphibians evolved from fishes about 360 million years ago and were the first vertebrates adapted to life on land. The word amphibian means "double life." It refers to the life history of many amphibians, which spend part of their life in water and part on land. There are three major groups of amphibians: salamanders, frogs, and toads, and caecilians. Salamanders, frogs, and toads can be found in Olympic National Park (ONP), but caecilians live only in tropical regions. Many amphibians are generalist predators, eating almost any prey they can fit into their mouths.

The use of singleplex and nested PCR to detect Batrachochytrium dendrobatidis in free-living frogs.

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Coutinho, Selene Dall'Acqua; Burke, Julieta Catarina; de Paula, Catia Dejuste; Rodrigues, Miguel Trefaut; Catão-Dias, José Luiz

2015-06-01

Many microorganisms are able to cause diseases in amphibians, and in the past few years one of the most reported has been Batrachochytrium dendrobatidis. This fungus was first reported in Brazil in 2005; following this, other reports were made in specimens deposited in museum collections, captive and free-living frogs. The aim of this study was to compare singleplex and nested-PCR techniques to detect B. dendrobatidis in free-living and apparently healthy adult frogs from the Brazilian Atlantic Forest. The sample collection area was a protected government park, with no general entrance permitted and no management of the animals there. Swabs were taken from the skin of 107 animals without macroscopic lesions and they were maintained in ethanol p.a. Fungal DNA was extracted and identification of B. dendrobatidis was performed using singleplex and nested-PCR techniques, employing specific primers sequences. B. dendrobatidis was detected in 61/107 (57%) and 18/107 (17%) animals, respectively by nested and singleplex-PCR. Nested-PCR was statistically more sensible than the conventional for the detection of B. dendrobatidis (Chi-square = 37.1; α = 1%) and the agreement between both techniques was considered just fair (Kappa = 0.27). The high prevalence obtained confirms that these fungi occur in free-living frogs from the Brazilian Atlantic Forest with no macroscopic lesions, characterizing the state of asymptomatic carrier. We concluded that the nested-PCR technique, due to its ease of execution and reproducibility, can be recommended as one of the alternatives in epidemiological surveys to detect B. dendrobatidis in healthy free-living frog populations.

Phylogeny and differentiation of reptilian and amphibian ranaviruses detected in Europe.

Science.gov (United States)

Stöhr, Anke C; López-Bueno, Alberto; Blahak, Silvia; Caeiro, Maria F; Rosa, Gonçalo M; Alves de Matos, António Pedro; Martel, An; Alejo, Alí; Marschang, Rachel E

2015-01-01

Ranaviruses in amphibians and fish are considered emerging pathogens and several isolates have been extensively characterized in different studies. Ranaviruses have also been detected in reptiles with increasing frequency, but the role of reptilian hosts is still unclear and only limited sequence data has been provided. In this study, we characterized a number of ranaviruses detected in wild and captive animals in Europe based on sequence data from six genomic regions (major capsid protein (MCP), DNA polymerase (DNApol), ribonucleoside diphosphate reductase alpha and beta subunit-like proteins (RNR-α and -β), viral homolog of the alpha subunit of eukaryotic initiation factor 2, eIF-2α (vIF-2α) genes and microsatellite region). A total of ten different isolates from reptiles (tortoises, lizards, and a snake) and four ranaviruses from amphibians (anurans, urodeles) were included in the study. Furthermore, the complete genome sequences of three reptilian isolates were determined and a new PCR for rapid classification of the different variants of the genomic arrangement was developed. All ranaviruses showed slight variations on the partial nucleotide sequences from the different genomic regions (92.6-100%). Some very similar isolates could be distinguished by the size of the band from the microsatellite region. Three of the lizard isolates had a truncated vIF-2α gene; the other ranaviruses had full-length genes. In the phylogenetic analyses of concatenated sequences from different genes (3223 nt/10287 aa), the reptilian ranaviruses were often more closely related to amphibian ranaviruses than to each other, and most clustered together with previously detected ranaviruses from the same geographic region of origin. Comparative analyses show that among the closely related amphibian-like ranaviruses (ALRVs) described to date, three recently split and independently evolving distinct genetic groups can be distinguished. These findings underline the wide host range of

Phylogeny and differentiation of reptilian and amphibian ranaviruses detected in Europe.

Directory of Open Access Journals (Sweden)

Anke C Stöhr

Full Text Available Ranaviruses in amphibians and fish are considered emerging pathogens and several isolates have been extensively characterized in different studies. Ranaviruses have also been detected in reptiles with increasing frequency, but the role of reptilian hosts is still unclear and only limited sequence data has been provided. In this study, we characterized a number of ranaviruses detected in wild and captive animals in Europe based on sequence data from six genomic regions (major capsid protein (MCP, DNA polymerase (DNApol, ribonucleoside diphosphate reductase alpha and beta subunit-like proteins (RNR-α and -β, viral homolog of the alpha subunit of eukaryotic initiation factor 2, eIF-2α (vIF-2α genes and microsatellite region. A total of ten different isolates from reptiles (tortoises, lizards, and a snake and four ranaviruses from amphibians (anurans, urodeles were included in the study. Furthermore, the complete genome sequences of three reptilian isolates were determined and a new PCR for rapid classification of the different variants of the genomic arrangement was developed. All ranaviruses showed slight variations on the partial nucleotide sequences from the different genomic regions (92.6-100%. Some very similar isolates could be distinguished by the size of the band from the microsatellite region. Three of the lizard isolates had a truncated vIF-2α gene; the other ranaviruses had full-length genes. In the phylogenetic analyses of concatenated sequences from different genes (3223 nt/10287 aa, the reptilian ranaviruses were often more closely related to amphibian ranaviruses than to each other, and most clustered together with previously detected ranaviruses from the same geographic region of origin. Comparative analyses show that among the closely related amphibian-like ranaviruses (ALRVs described to date, three recently split and independently evolving distinct genetic groups can be distinguished. These findings underline the wide host

Using omics and integrated multi-omics approaches to guide probiotic selection to mitigate chytridiomycosis and other emerging infectious diseases

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Eria Alaide Rebollar

2016-02-01

Full Text Available Emerging infectious diseases in wildlife are responsible for massive population declines. In amphibians, chytridiomycosis caused by Batrachochytrium dendrobatidis, Bd, has severely affected many amphibian populations and species around the world. One promising management strategy is probiotic bioaugmentation of antifungal bacteria on amphibian skin. In vivo experimental trials using bioaugmentation strategies have had mixed results, and therefore a more informed strategy is needed to select successful probiotic candidates. Metagenomic, transcriptomic, and metabolomic methods, colloquially called omics, are approaches that can better inform probiotic selection and optimize selection protocols. The integration of multiple omic data using bioinformatic and statistical tools and in silico models that link bacterial community structure with bacterial defensive function can allow the identification of species involved in pathogen inhibition. We recommend using 16S rRNA gene amplicon sequencing and methods such as indicator species analysis, the K-S Measure, and co-occurrence networks to identify bacteria that are associated with pathogen resistance in field surveys and experimental trials. In addition to 16S amplicon sequencing, we recommend approaches that give insight into symbiont function such as shotgun metagenomics, metatranscriptomics or metabolomics to maximize the probability of finding effective probiotic candidates, which can then be isolated in culture and tested in persistence and clinical trials. An effective mitigation strategy to ameliorate chytridiomycosis and other emerging infectious diseases is necessary; the advancement of omic methods and the integration of multiple omic data provide a promising avenue toward conservation of imperiled species.

Understanding Amphibian Declines Through Geographic Approaches

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Gallant, Alisa

2006-01-01

Growing concern over worldwide amphibian declines warrants serious examination. Amphibians are important to the proper functioning of ecosystems and provide many direct benefits to humans in the form of pest and disease control, pharmaceutical compounds, and even food. Amphibians have permeable skin and rely on both aquatic and terrestrial ecosystems during different seasons and stages of their lives. Their association with these ecosystems renders them likely to serve as sensitive indicators of environmental change. While much research on amphibian declines has centered on mysterious causes, or on causes that directly affect humans (global warming, chemical pollution, ultraviolet-B radiation), most declines are the result of habitat loss and habitat alteration. Improving our ability to characterize, model, and monitor the interactions between environmental variables and amphibian habitats is key to addressing amphibian conservation. In 2000, the U.S. Geological Survey (USGS) initiated the Amphibian Research and Monitoring Initiative (ARMI) to address issues surrounding amphibian declines.

Marginal Bayesian nonparametric model for time to disease arrival of threatened amphibian populations.

Science.gov (United States)

Zhou, Haiming; Hanson, Timothy; Knapp, Roland

2015-12-01

The global emergence of Batrachochytrium dendrobatidis (Bd) has caused the extinction of hundreds of amphibian species worldwide. It has become increasingly important to be able to precisely predict time to Bd arrival in a population. The data analyzed herein present a unique challenge in terms of modeling because there is a strong spatial component to Bd arrival time and the traditional proportional hazards assumption is grossly violated. To address these concerns, we develop a novel marginal Bayesian nonparametric survival model for spatially correlated right-censored data. This class of models assumes that the logarithm of survival times marginally follow a mixture of normal densities with a linear-dependent Dirichlet process prior as the random mixing measure, and their joint distribution is induced by a Gaussian copula model with a spatial correlation structure. To invert high-dimensional spatial correlation matrices, we adopt a full-scale approximation that can capture both large- and small-scale spatial dependence. An efficient Markov chain Monte Carlo algorithm with delayed rejection is proposed for posterior computation, and an R package spBayesSurv is provided to fit the model. This approach is first evaluated through simulations, then applied to threatened frog populations in Sequoia-Kings Canyon National Park. © 2015, The International Biometric Society.

Climate change and amphibians

OpenAIRE

Corn, P. S.

2005-01-01

Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines i...

Effect of road deicing salt on the susceptibility of amphibian embryos to infection by water molds.

Science.gov (United States)

Karraker, Nancy E; Ruthig, Gregory R

2009-01-01

Some causative agents of amphibian declines act synergistically to impact individual amphibians and their populations. In particular, pathogenic water molds (aquatic oomycetes) interact with environmental stressors and increase mortality in amphibian embryos. We documented colonization of eggs of three amphibian species, the wood frog (Rana sylvatica), the green frog (Rana clamitans), and the spotted salamander (Ambystoma maculatum), by water molds in the field and examined the interactive effects of road deicing salt and water molds, two known sources of mortality for amphibian embryos, on two species, R. clamitans and A. maculatum in the laboratory. We found that exposure to water molds did not affect embryonic survivorship in either A. maculatum or R. clamitans, regardless of the concentration of road salt to which their eggs were exposed. Road salt decreased survivorship of A. maculatum, but not R. clamitans, and frequency of malformations increased significantly in both species at the highest salinity concentration. The lack of an effect of water molds on survival of embryos and no interaction between road salt and water molds indicates that observations of colonization of these eggs by water molds in the field probably represent a secondary invasion of unfertilized eggs or of embryos that had died of other causes. Given increasing salinization of freshwater habitats on several continents and the global distribution of water molds, our results suggest that some amphibian species may not be susceptible to the combined effects of these factors, permitting amphibian decline researchers to devote their attention to other potential causes.

Chemosignals, hormones, and amphibian reproduction.

Science.gov (United States)

Woodley, Sarah

2015-02-01

This article is part of a Special Issue "Chemosignals and Reproduction". Amphibians are often thought of as relatively simple animals especially when compared to mammals. Yet the chemosignaling systems used by amphibians are varied and complex. Amphibian chemosignals are particularly important in reproduction, in both aquatic and terrestrial environments. Chemosignaling is most evident in salamanders and newts, but increasing evidence indicates that chemical communication facilitates reproduction in frogs and toads as well. Reproductive hormones shape the production, dissemination, detection, and responsiveness to chemosignals. A large variety of chemosignals have been identified, ranging from simple, invariant chemosignals to complex, variable blends of chemosignals. Although some chemosignals elicit straightforward responses, others have relatively subtle effects. Review of amphibian chemosignaling reveals a number of issues to be resolved, including: 1) the significance of the complex, individually variable blends of courtship chemosignals found in some salamanders, 2) the behavioral and/or physiological functions of chemosignals found in anuran "breeding glands", 3) the ligands for amphibian V2Rs, especially V2Rs expressed in the main olfactory epithelium, and 4) the mechanism whereby transdermal delivery of chemosignals influences behavior. To date, only a handful of the more than 7000 species of amphibians has been examined. Further study of amphibians should provide additional insight to the role of chemosignals in reproduction. Copyright © 2014 Elsevier Inc. All rights reserved.

Phylogeny and differentiation of reptilian and amphibian ranaviruses detected in Europe

OpenAIRE

Stöhr, Anke C.; López-Bueno, Alberto; Blahak, Silvia; Caeiro, Maria F.; De Matos, António Pedro Alves; Martel, An; Alejo, Alí; Marschang, Rachel E.; Rosa, Gonçalo M.

2015-01-01

Ranaviruses in amphibians and fish are considered emerging pathogens and several isolates have been extensively characterized in different studies. Ranaviruses have also been detected in reptiles with increasing frequency, but the role of reptilian hosts is still unclear and only limited sequence data has been provided. In this study, we characterized a number of ranaviruses detected in wild and captive animals in Europe based on sequence data from six genomic regions (major capsid protein (M...

Phylogeny, life history, and ecology contribute to differences in amphibian susceptibility to ranaviruses.

Science.gov (United States)

Hoverman, Jason T; Gray, Matthew J; Haislip, Nathan A; Miller, Debra L

2011-09-01

Research that identifies the potential host range of generalist pathogens as well as variation in host susceptibility is critical for understanding and predicting the dynamics of infectious diseases within ecological communities. Ranaviruses have been linked to amphibian die-off events worldwide with the greatest number of reported mortality events occurring in the United States. While reports of ranavirus-associated mortality events continue to accumulate, few data exist comparing the relative susceptibility of different species. Using a series of laboratory exposure experiments and comparative phylogenetics, we compared the susceptibilities of 19 amphibian species from two salamander families and five anurans families for two ranavirus isolates: frog virus 3 (FV3) and an FV3-like isolate from an American bullfrog culture facility. We discovered that ranaviruses were capable of infecting 17 of the 19 larval amphibian species tested with mortality ranging from 0 to 100%. Phylogenetic comparative methods demonstrated that species within the anuran family Ranidae were generally more susceptible to ranavirus infection compared to species from the other five families. We also found that susceptibility to infection was associated with species that breed in semi-permanent ponds, develop rapidly as larvae, and have limited range sizes. Collectively, these results suggest that phylogeny, life history characteristics, and habitat associations of amphibians have the potential to impact susceptibility to ranaviruses.

DNA barcoding amphibians and reptiles.

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Vences, Miguel; Nagy, Zoltán T; Sonet, Gontran; Verheyen, Erik

2012-01-01

Only a few major research programs are currently targeting COI barcoding of amphibians and reptiles (including chelonians and crocodiles), two major groups of tetrapods. Amphibian and reptile species are typically old, strongly divergent, and contain deep conspecific lineages which might lead to problems in species assignment with incomplete reference databases. As far as known, there is no single pair of COI primers that will guarantee a sufficient rate of success across all amphibian and reptile taxa, or within major subclades of amphibians and reptiles, which means that the PCR amplification strategy needs to be adjusted depending on the specific research question. In general, many more amphibian and reptile taxa have been sequenced for 16S rDNA, which for some purposes may be a suitable complementary marker, at least until a more comprehensive COI reference database becomes available. DNA barcoding has successfully been used to identify amphibian larval stages (tadpoles) in species-rich tropical assemblages. Tissue sampling, DNA extraction, and amplification of COI is straightforward in amphibians and reptiles. Single primer pairs are likely to have a failure rate between 5 and 50% if taxa of a wide taxonomic range are targeted; in such cases the use of primer cocktails or subsequent hierarchical usage of different primer pairs is necessary. If the target group is taxonomically limited, many studies have followed a strategy of designing specific primers which then allow an easy and reliable amplification of all samples.

Survival, gene and metabolite responses of Litoria verreauxii alpina frogs to fungal disease chytridiomycosis

Science.gov (United States)

Grogan, Laura F.; Mulvenna, Jason; Gummer, Joel P. A.; Scheele, Ben C.; Berger, Lee; Cashins, Scott D.; McFadden, Michael S.; Harlow, Peter; Hunter, David A.; Trengove, Robert D.; Skerratt, Lee F.

2018-03-01

The fungal skin disease chytridiomycosis has caused the devastating decline and extinction of hundreds of amphibian species globally, yet the potential for evolving resistance, and the underlying pathophysiological mechanisms remain poorly understood. We exposed 406 naïve, captive-raised alpine tree frogs (Litoria verreauxii alpina) from multiple populations (one evolutionarily naïve to chytridiomycosis) to the aetiological agent Batrachochytrium dendrobatidis in two concurrent and controlled infection experiments. We investigated (A) survival outcomes and clinical pathogen burdens between populations and clutches, and (B) individual host tissue responses to chytridiomycosis. Here we present multiple interrelated datasets associated with these exposure experiments, including animal signalment, survival and pathogen burden of 355 animals from Experiment A, and the following datasets related to 61 animals from Experiment B: animal signalment and pathogen burden; raw RNA-Seq reads from skin, liver and spleen tissues; de novo assembled transcriptomes for each tissue type; raw gene expression data; annotation data for each gene; and raw metabolite expression data from skin and liver tissues. These data provide an extensive baseline for future analyses.

Identifying species conservation strategies to reduce disease-associated declines

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Gerber, Brian D.; Converse, Sarah J.; Muths, Erin L.; Crockett, Harry J.; Mosher, Brittany A.; Bailey, Larissa L.

2018-01-01

Emerging infectious diseases (EIDs) are a salient threat to many animal taxa, causing local and global extinctions, altering communities and ecosystem function. The EID chytridiomycosis is a prominent driver of amphibian declines, which is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). To guide conservation policy, we developed a predictive decision-analytic model that combines empirical knowledge of host-pathogen metapopulation dynamics with expert judgment regarding effects of management actions, to select from potential conservation strategies. We apply our approach to a boreal toad (Anaxyrus boreas boreas) and Bd system, identifying optimal strategies that balance tradeoffs in maximizing toad population persistence and landscape-level distribution, while considering costs. The most robust strategy is expected to reduce the decline of toad breeding sites from 53% to 21% over 50 years. Our findings are incorporated into management policy to guide conservation planning. Our online modeling application provides a template for managers of other systems challenged by EIDs.

Effects of road salt on larval amphibian susceptibility to parasitism through behavior and immunocompetence.

Science.gov (United States)

Milotic, Dino; Milotic, Marin; Koprivnikar, Janet

2017-08-01

Large quantities of road salts are used for de-icing in temperate climates but often leach into aquatic ecosystems where they can cause harm to inhabitants, including reduced growth and survival. However, the implications of road salt exposure for aquatic animal susceptibility to pathogens and parasites have not yet been examined even though infectious diseases can significantly contribute to wildlife population declines. Through a field survey, we found a range of NaCl concentrations (50-560mg/L) in ponds known to contain larval amphibians, with lower levels found in sites close to gravel- rather than hard-surfaced roads. We then investigated how chronic exposure to environmentally-realistic levels of road salt (up to 1140mg/L) affected susceptibility to infection by trematode parasites (helminths) in larval stages of two amphibian species (Lithobates sylvaticus - wood frogs, and L. pipiens - northern leopard frogs) by considering effects on host anti-parasite behavior and white blood cell profiles. Wood frogs exposed to road salt had higher parasite loads, and also exhibited reduced anti-parasite behavior in these conditions. In contrast, infection intensity in northern leopard frogs had a non-monotonic response to road salts even though lymphocytes were only elevated at the highest concentration. Our results indicate the potential for chronic road salt exposure to affect larval amphibian susceptibility to pathogenic parasites through alterations of behavior and immunocompetence, with further studies needed at higher concentrations, as well as that of road salts on free-living parasite infectious stages. Copyright © 2017 Elsevier B.V. All rights reserved.

Climate forcing of an emerging pathogenic fungus across a montane multi-host community.

Science.gov (United States)

Clare, Frances C; Halder, Julia B; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S; Cunningham, Andrew A; Rowcliffe, Marcus; Garner, Trenton W J; Bosch, Jaime; Fisher, Matthew C

2016-12-05

Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Authors.

Natural disturbance reduces disease risk in endangered rainforest frog populations.

Science.gov (United States)

Roznik, Elizabeth A; Sapsford, Sarah J; Pike, David A; Schwarzkopf, Lin; Alford, Ross A

2015-08-21

Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11-28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

Bacterial flora on Cascades frogs in the Klamath Mountains of California

Science.gov (United States)

Karen Pope

2013-01-01

Amphibians are experiencing global declines due in part to the infectious disease chytridiomycosis. Some symbiotic bacteria residents on frog skin have been shown to inhibit the growth of Batrachochytrium dendrobatitis (Bd) but few studies have attempted to fully describe the resident bacterial flora of frog skin. We cultured and sequenced 130...

Amphibian Engineers in the Southwest Pacific

Science.gov (United States)

2017-03-08

too dangerous. The 1st Engineer Amphibian Brigade was relegated to truck duty in England instead of preparing for the cross-channel invasion.21 Before...and dumps through the swamp.93 91 Office of the Chief Engineer , Amphibian Engineer ...inland, whereas the DUKW (and LVT) could drive direct from ship to dump site. 116 Office of the Chief Engineer , Amphibian Engineer Operations, 320-21

Chytrid Fungus, Batrachochytrium dendrobatidis , in Wild Populations of the Lake Titicaca Frog, Telmatobius culeus, in Peru.

Science.gov (United States)

Berenguel, Raul A; Elias, Roberto K; Weaver, Thomas J; Reading, Richard P

2016-10-01

The Lake Titicaca frog (Telmatobius culeus) is critically endangered, primarily from overexploitation. However, additional threats, such as chytrid fungus ( Batrachochytrium dendrobatidis ), are poorly studied. We found moderate levels of chytrid infection using quantitative PCR. Our results enhance our understanding of chytrid tolerance to high pH and low water temperature.

Efficacy of chemical disinfectants for the containment of the salamander chytrid fungus Batrachochytrium salamandrivorans

OpenAIRE

Van Rooij, Pascale; Pasmans, Frank; Coen, Yanaïka; Martel, An

2017-01-01

The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal) causes European salamander declines. Proper hygiene protocols including disinfection procedures are crucial to prevent disease transmission. Here, the efficacy of chemical disinfectants in killing Bsal was evaluated. At all tested conditions, Biocidal (R), Chloramine-T (R), Dettol medical (R), Disolol (R), ethanol, F10 (R), Hibiscrub (R), potassium permanganate, Safe4 (R), sodium hypochlorite, and Virkon S (R), were ...

The state of amphibians in the United States

Science.gov (United States)

Muths, E.; Adams, M.J.; Grant, E.H.C.; Miller, D.; Corn, P.S.; Ball, L.C.

2012-01-01

More than 25 years ago, scientists began to identify unexplained declines in amphibian populations around the world. Much has been learned since then, but amphibian declines have not abated and the interactions among the various threats to amphibians are not clear. Amphibian decline is a problem of local, national, and international scope that can affect ecosystem function, biodiversity, and commerce. This fact sheet provides a snapshot of the state of the amphibians and introduces examples to illustrate the range of issues in the United States.

Altered Reproductive Function and Amphibian Declines

OpenAIRE

Gallipeau, Sherrie

2014-01-01

Agrochemical exposure is one of the factors that contributes to worldwide amphibian declines. Most studies that examine agrochemicals and amphibian declines focus on toxicity. However, declines are more likely caused by the sub-lethal effects of agrochemical exposure. Past emphases on the lethal effects of agrochemical exposure have overshadowed the contribution of decreased recruitment in amphibian declines. Additionally, studies that examine agrochemicals and reproductive function tend to f...

Overview of chytrid emergence and impacts on amphibians

Science.gov (United States)

2016-01-01

Chytridiomycosis is an emerging infectious disease of amphibians that affects over 700 species on all continents where amphibians occur. The amphibian–chytridiomycosis system is complex, and the response of any amphibian species to chytrid depends on many aspects of the ecology and evolutionary history of the amphibian, the genotype and phenotype of the fungus, and how the biological and physical environment can mediate that interaction. Impacts of chytridiomycosis on amphibians are varied; some species have been driven extinct, populations of others have declined severely, whereas still others have not obviously declined. Understanding patterns and mechanisms of amphibian responses to chytrids is critical for conservation and management. Robust estimates of population numbers are needed to identify species at risk, prioritize taxa for conservation actions, design management strategies for managing populations and species, and to develop effective measures to reduce impacts of chytrids on amphibians. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’. PMID:28080989

Effects of pond salinization on survival rate of amphibian hosts infected with the chytrid fungus.

Science.gov (United States)

Stockwell, Michelle Pirrie; Storrie, Lachlan James; Pollard, Carla Jean; Clulow, John; Mahony, Michael Joseph

2015-04-01

The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of amphibian populations worldwide, but management options are limited. Recent studies show that sodium chloride (NaCl) has fungicidal properties that reduce the mortality rates of infected hosts in captivity. We investigated whether similar results can be obtained by adding salt to water bodies in the field. We increased the salinity of 8 water bodies to 2 or 4 ppt and left an additional 4 water bodies with close to 0 ppt and monitored salinity for 18 months. Captively bred tadpoles of green and golden bell frog (Litoria aurea) were released into each water body and their development, levels of B. dendrobatidis infection, and survival were monitored at 1, 4, and 12 months. The effect of salt on the abundance of nontarget organisms was also investigated in before and after style analyses. Salinities remained constant over time with little intervention. Hosts in water bodies with 4 ppt salt had a significantly lower prevalence of chytrid infection and higher survival, following metamorphosis, than hosts in 0 ppt salt. Tadpoles in the 4 ppt group were smaller in length after 1 month in the release site than those in the 0 and 2 ppt groups, but after metamorphosis body size in all water bodies was similar . In water bodies with 4 ppt salt, the abundance of dwarf tree frogs (Litoria fallax), dragonfly larvae, and damselfly larvae was lower than in water bodies with 0 and 2 ppt salt, which could have knock-on effects for community structure. Based on our results, salt may be an effective field-based B. dendrobatidis mitigation tool for lentic amphibians that could contribute to the conservation of numerous susceptible species. However, as in all conservation efforts, these benefits need to be weighed against negative effects on both target and nontarget organisms. © 2014 Society for Conservation Biology.

Efficacy of chemical disinfectants for the containment of the salamander chytrid fungus Batrachochytrium salamandrivorans.

Science.gov (United States)

Van Rooij, Pascale; Pasmans, Frank; Coen, Yanaika; Martel, An

2017-01-01

The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal) causes European salamander declines. Proper hygiene protocols including disinfection procedures are crucial to prevent disease transmission. Here, the efficacy of chemical disinfectants in killing Bsal was evaluated. At all tested conditions, Biocidal®, Chloramine-T®, Dettol medical®, Disolol®, ethanol, F10®, Hibiscrub®, potassium permanganate, Safe4®, sodium hypochlorite, and Virkon S®, were effective at killing Bsal. Concentrations of 5% sodium chloride or lower, 0.01% peracetic acid and 0.001-1% copper sulphate were inactive against Bsal. None of the conditions tested for hydrogen peroxide affected Bsal viability, while it did kill Batrachochytrium dendrobatidis (Bd). For Bsal, enzymatic breakdown of hydrogen peroxide by catalases and specific morphological features (clustering of sporangia, development of new sporangia within the original sporangium), were identified as fungal factors altering susceptibility to several of the disinfectants tested. Based on the in vitro results we recommend 1% Virkon S®, 4% sodium hypochlorite and 70% ethanol for disinfecting equipment in the field, lab or captive setting, with a minimal contact time of 5 minutes for 1% Virkon S® and 1 minute for the latter disinfectants. These conditions not only efficiently target Bsal, but also Bd and Ranavirus.

Efficacy of chemical disinfectants for the containment of the salamander chytrid fungus Batrachochytrium salamandrivorans.

Directory of Open Access Journals (Sweden)

Pascale Van Rooij

Full Text Available The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal causes European salamander declines. Proper hygiene protocols including disinfection procedures are crucial to prevent disease transmission. Here, the efficacy of chemical disinfectants in killing Bsal was evaluated. At all tested conditions, Biocidal®, Chloramine-T®, Dettol medical®, Disolol®, ethanol, F10®, Hibiscrub®, potassium permanganate, Safe4®, sodium hypochlorite, and Virkon S®, were effective at killing Bsal. Concentrations of 5% sodium chloride or lower, 0.01% peracetic acid and 0.001-1% copper sulphate were inactive against Bsal. None of the conditions tested for hydrogen peroxide affected Bsal viability, while it did kill Batrachochytrium dendrobatidis (Bd. For Bsal, enzymatic breakdown of hydrogen peroxide by catalases and specific morphological features (clustering of sporangia, development of new sporangia within the original sporangium, were identified as fungal factors altering susceptibility to several of the disinfectants tested. Based on the in vitro results we recommend 1% Virkon S®, 4% sodium hypochlorite and 70% ethanol for disinfecting equipment in the field, lab or captive setting, with a minimal contact time of 5 minutes for 1% Virkon S® and 1 minute for the latter disinfectants. These conditions not only efficiently target Bsal, but also Bd and Ranavirus.

Suitability of amphibians and reptiles for translocation.

Science.gov (United States)

Germano, Jennifer M; Bishop, Phillip J

2009-02-01

Translocations are important tools in the field of conservation. Despite increased use over the last few decades, the appropriateness of translocations for amphibians and reptiles has been debated widely over the past 20 years. To provide a comprehensive evaluation of the suitability of amphibians and reptiles for translocation, we reviewed the results of amphibian and reptile translocation projects published between 1991 and 2006. The success rate of amphibian and reptile translocations reported over this period was twice that reported in an earlier review in 1991. Success and failure rates were independent of the taxonomic class (Amphibia or Reptilia) released. Reptile translocations driven by human-wildlife conflict mitigation had a higher failure rate than those motivated by conservation, and more recent projects of reptile translocations had unknown outcomes. The outcomes of amphibian translocations were significantly related to the number of animals released, with projects releasing over 1000 individuals being most successful. The most common reported causes of translocation failure were homing and migration of introduced individuals out of release sites and poor habitat. The increased success of amphibian and reptile translocations reviewed in this study compared with the 1991 review is encouraging for future conservation projects. Nevertheless, more preparation, monitoring, reporting of results, and experimental testing of techniques and reintroduction questions need to occur to improve translocations of amphibians and reptiles as a whole.

Impending conservation crisis for Southeast Asian amphibians.

Science.gov (United States)

Rowley, Jodi; Brown, Rafe; Bain, Raoul; Kusrini, Mirza; Inger, Robert; Stuart, Bryan; Wogan, Guin; Thy, Neang; Chan-Ard, Tanya; Trung, Cao Tien; Diesmos, Arvin; Iskandar, Djoko T; Lau, Michael; Ming, Leong Tzi; Makchai, Sunchai; Truong, Nguyen Quang; Phimmachak, Somphouthone

2010-06-23

With an understudied amphibian fauna, the highest deforestation rate on the planet and high harvesting pressures, Southeast Asian amphibians are facing a conservation crisis. Owing to the overriding threat of habitat loss, the most critical conservation action required is the identification and strict protection of habitat assessed as having high amphibian species diversity and/or representing distinctive regional amphibian faunas. Long-term population monitoring, enhanced survey efforts, collection of basic biological and ecological information, continued taxonomic research and evaluation of the impact of commercial trade for food, medicine and pets are also needed. Strong involvement of regional stakeholders, students and professionals is essential to accomplish these actions.

The metamorphosis of amphibian toxicogenomics

Directory of Open Access Journals (Sweden)

Caren eHelbing

2012-03-01

Full Text Available Amphibians are important vertebrates in toxicology often representing both aquatic and terrestrial forms within the life history of the same species. Of the thousands of species, only two have substantial genomics resources: the recently published genome of the Pipid, Xenopus (Silurana tropicalis, and transcript information (and ongoing genome sequencing project of Xenopus laevis. However, many more species representative of regional ecological niches and life strategies are used in toxicology worldwide. Since Xenopus species diverged from the most populous frog family, the Ranidae, ~200 million years ago, there are notable differences between them and the even more distant Caudates (salamanders and Caecilians. These differences include genome size, gene composition, and extent of polyploidization. Application of toxicogenomics to amphibians requires the mobilization of resources and expertise to develop de novo sequence assemblies and analysis strategies for a broader range of amphibian species. The present mini-review will present the advances in toxicogenomics as pertains to amphibians with particular emphasis upon the development and use of genomic techniques (inclusive of transcriptomics, proteomics, and metabolomics and the challenges inherent therein.

Dramatic Declines of Montane Frogs in a Central African Biodiversity Hotspot

Science.gov (United States)

Hirschfeld, Mareike; Blackburn, David C.; Doherty-Bone, Thomas M.; Gonwouo, LeGrand Nono; Ghose, Sonia; Rödel, Mark-Oliver

2016-01-01

Amphibian populations are vanishing worldwide. Declines and extinctions of many populations have been attributed to chytridiomycosis, a disease induced by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). In Africa, however, changes in amphibian assemblages were typically attributed to habitat change. We conducted a retrospective study utilizing field surveys from 2004–2012 of the anuran faunas on two mountains in western Cameroon, a hotspot of African amphibian diversity. The number of species detected was negatively influenced by year, habitat degradation, and elevation, and we detected a decline of certain species. Because another study in this region revealed an emergence of Bd in 2008, we screened additional recent field-collected samples and also pre-decline preserved museum specimens for the presence of Bd supporting emergence before 2008. When comparing the years before and after Bd detection, we found significantly diminished frog species richness and abundance on both mountains after Bd emergence. Our analyses suggest that this may be the first disease-driven community-level decline in anuran biodiversity in Central Africa. The disappearance of several species known to tolerate habitat degradation, and a trend of stronger declines at higher elevations, are consistent with Bd-induced declines in other regions. Not all species decreased; populations of some species remained constant, and others increased after the emergence of Bd. This variation might be explained by species-specific differences in infection probability. Increased habitat protection and Bd-mitigation strategies are needed for sustaining diverse amphibian communities such as those on Mt. Manengouba, which contains nearly half of Cameroon’s frog diversity. PMID:27149624

Dramatic Declines of Montane Frogs in a Central African Biodiversity Hotspot.

Directory of Open Access Journals (Sweden)

Mareike Hirschfeld

Full Text Available Amphibian populations are vanishing worldwide. Declines and extinctions of many populations have been attributed to chytridiomycosis, a disease induced by the pathogenic fungus Batrachochytrium dendrobatidis (Bd. In Africa, however, changes in amphibian assemblages were typically attributed to habitat change. We conducted a retrospective study utilizing field surveys from 2004-2012 of the anuran faunas on two mountains in western Cameroon, a hotspot of African amphibian diversity. The number of species detected was negatively influenced by year, habitat degradation, and elevation, and we detected a decline of certain species. Because another study in this region revealed an emergence of Bd in 2008, we screened additional recent field-collected samples and also pre-decline preserved museum specimens for the presence of Bd supporting emergence before 2008. When comparing the years before and after Bd detection, we found significantly diminished frog species richness and abundance on both mountains after Bd emergence. Our analyses suggest that this may be the first disease-driven community-level decline in anuran biodiversity in Central Africa. The disappearance of several species known to tolerate habitat degradation, and a trend of stronger declines at higher elevations, are consistent with Bd-induced declines in other regions. Not all species decreased; populations of some species remained constant, and others increased after the emergence of Bd. This variation might be explained by species-specific differences in infection probability. Increased habitat protection and Bd-mitigation strategies are needed for sustaining diverse amphibian communities such as those on Mt. Manengouba, which contains nearly half of Cameroon's frog diversity.

[Jaws of amphibians and reptiles].

Science.gov (United States)

Tanimoto, Masahiro

2005-04-01

Big jaws of amphibians and reptiles are mainly treated in this article. In amphibians enlarged skulls are for the big jaw in contrast with human's skulls for the brain. For example, famous fossils of Homo diluvii testis are ones of salamanders in fact. In reptiles, mosasaur jaws and teeth and their ecology are introduced for instance.

The North American Amphibian Monitoring Program. [abstract

Science.gov (United States)

Griffin, J.

1998-01-01

The North American Amphibian Monitoring Program has been under development for the past three years. The monitoring strategy for NAAMP has five main prongs: terrestrial salamander surveys, calling surveys, aquatic surveys, western surveys, and atlassing. Of these five, calling surveys were selected as one of the first implementation priorities due to their friendliness to volunteers of varying knowledge levels, relative low cost, and the fact that several groups had already pioneered the techniques involved. While some states and provinces had implemented calling surveys prior to NAAMP, like WI and IL, most states and provinces had little or no history of state/provincewide amphibian monitoring. Thus, the majority of calling survey programs were initiated in the past two years. To assess the progress of this pilot phase, a program review was conducted on the status of the NAAMP calling survey program, and the results of that review will be presented at the meeting. Topics to be discussed include: who is doing what where, extent of route coverage, the continuing random route discussions, quality assurance, strengths and weaknesses of calling surveys, reliability of data, and directions for the future. In addition, a brief overview of the DISPro project will be included. DISPro is a new amphibian monitoring program in National Parks, funded by the Demonstration of Intensive Sites Program (DISPro) through the EPA and NPS. It will begin this year at Big Bend and Shenandoah National Parks. The purpose of the DISPro Amphibian Project will be to investigate relationships between environmental factors and stressors and the distribution, abundance, and health of amphibians in these National Parks. At each Park, amphibian long-term monitoring protocols will be tested, distributions and abundance of amphibians will be mapped, and field research experiments will be conducted to examine stressor effects on amphibians (e.g., ultraviolet radiation, contaminants, acidification).

Effectiveness of amphibians as biodiversity surrogates in pond conservation.

Science.gov (United States)

Ilg, Christiane; Oertli, Beat

2017-04-01

Amphibian decline has led to worldwide conservation efforts, including the identification and designation of sites for their protection. These sites could also play an important role in the conservation of other freshwater taxa. In 89 ponds in Switzerland, we assessed the effectiveness of amphibians as a surrogate for 4 taxonomic groups that occur in the same freshwater ecosystems as amphibians: dragonflies, aquatic beetles, aquatic gastropods, and aquatic plants. The ponds were all of high value for amphibian conservation. Cross-taxon correlations were tested for species richness and conservation value, and Mantel tests were used to investigate community congruence. Species richness, conservation value, and community composition of amphibians were weakly congruent with these measures for the other taxonomic groups. Paired comparisons for the 5 groups considered showed that for each metric, amphibians had the lowest degree of congruence. Our results imply that site designation for amphibian conservation will not necessarily provide protection for freshwater biodiversity as a whole. To provide adequate protection for freshwater species, we recommend other taxonomic groups be considered in addition to amphibians in the prioritization and site designation process. © 2016 Society for Conservation Biology.

Occurrence of pesticides in water and sediment collected from amphibian habitats located throughout the United States, 2009-10

Science.gov (United States)

Smalling, Kelly L.; Orlando, James L.; Calhoun, Daniel; Battaglin, William A.; Kuivila, Kathryn

2012-01-01

Water and bed-sediment samples were collected by the U.S. Geological Survey (USGS) in 2009 and 2010 from 11 sites within California and 18 sites total in Colorado, Georgia, Idaho, Louisiana, Maine, and Oregon, and were analyzed for a suite of pesticides by the USGS. Water samples and bed-sediment samples were collected from perennial or seasonal ponds located in amphibian habitats in conjunction with research conducted by the USGS Amphibian Research and Monitoring Initiative and the USGS Toxic Substances Hydrology Program. Sites selected for this study in three of the states (California, Colorado, and Orgeon) have no direct pesticide application and are considered undeveloped and remote. Sites selected in Georgia, Idaho, Louisiana, and Maine were in close proximity to either agricultural or suburban areas. Water and sediment samples were collected once in 2009 during amphibian breeding seasons. In 2010, water samples were collected twice. The first sampling event coincided with the beginning of the frog breeding season for the species of interest, and the second event occurred 10-12 weeks later when pesticides were being applied to the surrounding areas. Additionally, water was collected during each sampling event to measure dissolved organic carbon, nutrients, and the fungus, Batrachochytrium dendrobatidis, which has been linked to amphibian declines worldwide. Bed-sediment samples were collected once during the beginning of the frog breeding season, when the amphibians are thought to be most at risk to pesticides. Results of this study are reported for the following two geographic scales: (1) for a national scale, by using data from the 29 sites that were sampled from seven states, and (2) for California, by using data from the 11 sampled sites in that state. Water samples were analyzed for 96 pesticides by using gas chromatography/mass spectrometry. A total of 24 pesticides were detected in one or more of the 54 water samples, including 7 fungicides, 10

Colloquium paper: are we in the midst of the sixth mass extinction? A view from the world of amphibians.

Science.gov (United States)

Wake, David B; Vredenburg, Vance T

2008-08-12

Many scientists argue that we are either entering or in the midst of the sixth great mass extinction. Intense human pressure, both direct and indirect, is having profound effects on natural environments. The amphibians--frogs, salamanders, and caecilians--may be the only major group currently at risk globally. A detailed worldwide assessment and subsequent updates show that one-third or more of the 6,300 species are threatened with extinction. This trend is likely to accelerate because most amphibians occur in the tropics and have small geographic ranges that make them susceptible to extinction. The increasing pressure from habitat destruction and climate change is likely to have major impacts on narrowly adapted and distributed species. We show that salamanders on tropical mountains are particularly at risk. A new and significant threat to amphibians is a virulent, emerging infectious disease, chytridiomycosis, which appears to be globally distributed, and its effects may be exacerbated by global warming. This disease, which is caused by a fungal pathogen and implicated in serious declines and extinctions of >200 species of amphibians, poses the greatest threat to biodiversity of any known disease. Our data for frogs in the Sierra Nevada of California show that the fungus is having a devastating impact on native species, already weakened by the effects of pollution and introduced predators. A general message from amphibians is that we may have little time to stave off a potential mass extinction.

Electron microscopy of Chytridiomycosis and the need to re-examine the disease from the gene to the cell

International Nuclear Information System (INIS)

Hyatt, A.; Siddon, N.; Speare, R.

2003-01-01

Full text: Over the past three decades there has been a global decline of amphibian populations. A variety of causative factors, including increased ultra violet radiation, habitat destruction and chemical pollution have been proposed; these, however, have not been correlated with all amphibian declines in the protected areas of Australia or overseas. During the past five years a network of electron microscopists, veterinary pathologists, molecular biologists and ecologists have been working on identifying the etiological agent. Examination of skin from a large number of dead and moribund frogs revealed 'a fungus belonging to the phylum Chytridiomycota and order Chytridiales. The fungus has been demonstrated to cause the disease chytridiomycosis which is now recognised as a fatal disease of amphibians and is the most common disease of Australian frogs. The fungus (Batrachochytrium dendrobatidis) was originally identified by electron microscopy, and is the only member of the Chytridiomycota that causes disease in vertebrates. The fungus has a broad amphibian host range and occurs worldwide. A total of 94 amphibian species from 15 families have been found infected with B. dendrobatidis, from Australia, South America, Central America, North America, Europe, New Zealand and Africa. Electron microscopy (transmission, scanning, immuno and cryo) provided pivotal information on pathogen identification and understanding of the life cycle of the organism. However, what light and electron microscopy has not been able to elucidate is the cause of death within the infected animals. Many veterinary pathologists have examined the 'pathology' of the disease but are unable to agree on the probable causes (physiological processes) associated with the death of the infected animals. Two hypotheses exist the chytrid irreversibly affects the osmoregulatory ability of the amphibians and the chytrid releases a toxin that over time leads to the death of the animals. The cause of death

Louisiana ESI: REPTILES (Reptile and Amphibian Polygons)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for reptiles and amphibians in coastal Louisiana. Vector polygons represent reptile and amphibian habitats,...

Modeling effects of conservation grassland losses on amphibian habitat

Science.gov (United States)

Mushet, David M.; Neau, Jordan L.; Euliss, Ned H.

2014-01-01

Amphibians provide many ecosystem services valued by society. However, populations have declined globally with most declines linked to habitat change. Wetlands and surrounding terrestrial grasslands form habitat for amphibians in the North American Prairie Pothole Region (PPR). Wetland drainage and grassland conversion have destroyed or degraded much amphibian habitat in the PPR. However, conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining grasslands on agricultural lands. We used an ecosystem services model (InVEST) parameterized for the PPR to quantify amphibian habitat over a six-year period (2007–2012). We then quantified changes in availability of amphibian habitat under various land-cover scenarios representing incremental losses (10%, 25%, 50%, 75%, and 100%) of CRP grasslands from 2012 levels. The area of optimal amphibian habitat in the four PPR ecoregions modeled (i.e., Northern Glaciated Plains, Northwestern Glaciated Plains, Lake Agassiz Plain, Des Moines Lobe) declined by approximately 22%, from 3.8 million ha in 2007 to 2.9 million ha in 2012. These losses were driven by the conversion of CRP grasslands to croplands, primarily for corn and soybean production. Our modeling identified an additional 0.8 million ha (26%) of optimal amphibian habitat that would be lost if remaining CRP lands are returned to crop production. An economic climate favoring commodity production over conservation has resulted in substantial losses of amphibian habitat across the PPR that will likely continue into the future. Other regions of the world face similar challenges to maintaining amphibian habitats.

Diversity of aquatic Pseudomonas species and their activity against the fish pathogenic oomycete Saprolegnia

NARCIS (Netherlands)

Liu, Y.; Rzeszutek, E.; Voort, van der M.; Wu, C.H.; Thoen, E.; Skaar, I.; Bulone, V.; Dorrestein, P.C.; Raaijmakers, J.M.; Bruijn, de I.

2015-01-01

Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of

Amphibians and reptiles of the state of Hidalgo, Mexico

OpenAIRE

Lemos-Espinal, Julio; Smith, Geoffrey

2015-01-01

We compiled a checklist of the amphibians and reptiles of the state of Hidalgo, Mexico. The herpetofauna of Hidalgo consists of a total of 175 species: 54 amphibians (14 salamanders and 40 anurans); and 121 reptiles (one crocodile, five turtles, 36 lizards, 79 snakes). These taxa represent 32 families (12 amphibian families, 20 reptile families) and 87 genera (24 amphibian genera, 63 reptile genera). Two of these species are non-native species (Hemidactylus frenatus Duméril and Bibron, 1836 a...

Countryside biogeography of Neotropical reptiles and amphibians.

Science.gov (United States)

Mendenhall, Chase D; Frishkoff, Luke O; Santos-Barrera, Georgina; Pacheco, Jesús; Mesfun, Eyobed; Mendoza Quijano, Fernando; Ehrlich, Paul R; Ceballos, Gerardo; Daily, Gretchen C; Pringle, Robert M

2014-04-01

The future of biodiversity and ecosystem services depends largely on the capacity of human-dominated ecosystems to support them, yet this capacity remains largely unknown. Using the framework of countryside biogeography, and working in the Las Cruces system of Coto Brus, Costa Rica, we assessed reptile and amphibian assemblages within four habitats that typify much of the Neotropics: sun coffee plantations (12 sites), pasture (12 sites), remnant forest elements (12 sites), and a larger, contiguous protected forest (3 sites in one forest). Through analysis of 1678 captures of 67 species, we draw four primary conclusions. First, we found that the majority of reptile (60%) and amphibian (70%) species in this study used an array of habitat types, including coffee plantations and actively grazed pastures. Second, we found that coffee plantations and pastures hosted rich, albeit different and less dense, reptile and amphibian biodiversity relative to the 326-ha Las Cruces Forest Reserve and neighboring forest elements. Third, we found that the small ribbons of "countryside forest elements" weaving through farmland collectively increased the effective size of a 326-ha local forest reserve 16-fold for reptiles and 14-fold for amphibians within our 236-km2 study area. Therefore, countryside forest elements, often too small for most remote sensing techniques to identify, are contributing -95% of the available habitat for forest-dependent reptiles and amphibians in our largely human-dominated study region. Fourth, we found large and pond-reproducing amphibians to prefer human-made habitats, whereas small, stream-reproducing, and directly developing species are more dependent on forest elements. Our investigation demonstrates that tropical farming landscapes can support substantial reptile and amphibian biodiversity. Our approach provides a framework for estimating the conservation value of the complex working landscapes that constitute roughly half of the global land surface

Partners in amphibian and reptile conservation 2013 annual report

Science.gov (United States)

Conrad, Paulette M.; Weir, Linda A.; Nanjappa, Priya

2014-01-01

Partners in Amphibian and Reptile Conservation (PARC) was established in 1999 to address the widespread declines, extinctions, and range reductions of amphibians and reptiles, with a focus on conservation of taxa and habitats in North America. Amphibians and reptiles are affected by a broad range of human activities, both as incidental effects of habitat alteration and direct effect from overexploitation; these animals are also challenged by the perception that amphibians and reptiles are either dangerous or of little environmental or economic value. However, PARC members understand these taxa are important parts of our natural an cultural heritage and they serve important roles in ecosystems throughout the world. With many amphibians and reptiles classified as threatened with extinction, conservation of these animals has never been more important.

Are we in the midst of the sixth mass extinction? A view from the world of amphibians

Science.gov (United States)

Wake, David B.; Vredenburg, Vance T.

2008-01-01

Many scientists argue that we are either entering or in the midst of the sixth great mass extinction. Intense human pressure, both direct and indirect, is having profound effects on natural environments. The amphibians—frogs, salamanders, and caecilians—may be the only major group currently at risk globally. A detailed worldwide assessment and subsequent updates show that one-third or more of the 6,300 species are threatened with extinction. This trend is likely to accelerate because most amphibians occur in the tropics and have small geographic ranges that make them susceptible to extinction. The increasing pressure from habitat destruction and climate change is likely to have major impacts on narrowly adapted and distributed species. We show that salamanders on tropical mountains are particularly at risk. A new and significant threat to amphibians is a virulent, emerging infectious disease, chytridiomycosis, which appears to be globally distributed, and its effects may be exacerbated by global warming. This disease, which is caused by a fungal pathogen and implicated in serious declines and extinctions of >200 species of amphibians, poses the greatest threat to biodiversity of any known disease. Our data for frogs in the Sierra Nevada of California show that the fungus is having a devastating impact on native species, already weakened by the effects of pollution and introduced predators. A general message from amphibians is that we may have little time to stave off a potential mass extinction. PMID:18695221

Amphibian recovery after a decrease in acidic precipitation.

Science.gov (United States)

Dolmen, Dag; Finstad, Anders Gravbrøt; Skei, Jon Kristian

2018-04-01

We here report the first sign of amphibian recovery after a strong decline due to acidic precipitation over many decades and peaking around 1980-90. In 2010, the pH level of ponds and small lakes in two heavily acidified areas in southwestern Scandinavia (Aust-Agder and Østfold in Norway) had risen significantly at an (arithmetic) average of 0.14 since 1988-89. Parallel with the general rise in pH, amphibians (Rana temporaria, R. arvalis, Bufo bufo, Lissotriton vulgaris, and Triturus cristatus) had become significantly more common: the frequency of amphibian localities rose from 33% to 49% (n = 115), and the average number of amphibian species per locality had risen from 0.51 to 0.88. In two other (reference) areas, one with better buffering capacity (Telemark, n = 21) and the other with much less input of acidic precipitation (Nord-Trøndelag, n = 106), there were no significant changes in pH or amphibians.

Amphibian haematology: Metamorphosis-related changes in blood cells

DEFF Research Database (Denmark)

Rosenkilde, Per; Sørensen, Inger; Ussing, Anne Phaff

1995-01-01

Zoofysiologi, Amphibian metamorphosis, Haematology, Immunosuppression, Immunological Tolerance, Protozoan Infection, metamorfose, springpadder, ontogenese, halepadder.......Zoofysiologi, Amphibian metamorphosis, Haematology, Immunosuppression, Immunological Tolerance, Protozoan Infection, metamorfose, springpadder, ontogenese, halepadder....

Invasive reptiles and amphibians.

Science.gov (United States)

Moutou, F; Pastoret, P P

2010-08-01

Although they are frequently lumped together, reptiles and amphibians belong to two very different zoological groups. Nevertheless, one fact is clear: while numerous reptile and amphibian species on Earth are in decline, others have taken advantage of trade or human movements to become established in new lands, adopting different, and sometimes unusual, strategies. The authors have taken a few examples from these two zoological groups that illustrate the majority of cases. A brief analysis of the causes and effects of their introductions into new areas reveals connections with economic interests, trade in companion animals, medical research and public health.

Book review: The ecology and behavior of amphibians

Science.gov (United States)

Walls, Susan C.

2008-01-01

This state‐of‐the‐art book has made its timely emergence amid a crisis of global magnitude: that of population declines, range reductions, and extinctions of numerous species of amphibians. A clear understanding of the fundamental concepts in amphibian biology is crucial to the success of any conservation effort. This volume compiles the information necessary to acquire that basic understanding. It is a comprehensive synthesis of both traditional and contemporary facets of amphibian biology, spanning a breadth of topics ranging from phylogeny, physiology, behavior, population and community ecology, and conservation. As such, it undoubtedly takes its place among contemporary volumes as the single, authoritative source for basic topics relevant to amphibian life.

Predation of Ladybird Beetles (Coleoptera: Coccinellidae) by Amphibians.

Science.gov (United States)

Sloggett, John J

2012-07-18

Studies of predation of ladybird beetles (Coccinellidae) have focused on a limited number of predator taxa, such as birds and ants, while other potential predators have received limited attention. I here consider amphibians as predators of ladybirds. Published amphibian gut analyses show that ladybirds are quite often eaten by frogs and toads (Anura), with recorded frequencies reaching up to 15% of dietary items. Salamanders (Caudata) eat ladybirds less frequently, probably as their habits less often bring them into contact with the beetles. Amphibians do not appear to be deleteriously affected by the potentially toxic alkaloids that ladybirds possess. Amphibians, especially frogs and toads, use primarily prey movement as a release cue to attack their food; it is thus likely that their ability to discriminate against ladybirds and other chemically defended prey is limited. Because of this poor discriminatory power, amphibians have apparently evolved non-specific resistance to prey defensive chemicals, including ladybird alkaloids. Although amphibian-related ladybird mortality is limited, in certain habitats it could outweigh mortality from more frequently studied predators, notably birds. The gut analyses from the herpetological literature used in this study, suggest that in studying predation of insects, entomologists should consider specialized literature on other animal groups.

amphibian_biomarker_data

Data.gov (United States)

U.S. Environmental Protection Agency — Amphibian metabolite data used in Snyder, M.N., Henderson, W.M., Glinski, D.G., Purucker, S. T., 2017. Biomarker analysis of american toad (Anaxyrus americanus) and...

Global patterns of amphibian phylogenetic diversity

DEFF Research Database (Denmark)

Fritz, Susanne; Rahbek, Carsten

2012-01-01

Aim  Phylogenetic diversity can provide insight into how evolutionary processes may have shaped contemporary patterns of species richness. Here, we aim to test for the influence of phylogenetic history on global patterns of amphibian species richness, and to identify areas where macroevolutionary...... processes such as diversification and dispersal have left strong signatures on contemporary species richness. Location  Global; equal-area grid cells of approximately 10,000 km2. Methods  We generated an amphibian global supertree (6111 species) and repeated analyses with the largest available molecular...... phylogeny (2792 species). We combined each tree with global species distributions to map four indices of phylogenetic diversity. To investigate congruence between global spatial patterns of amphibian species richness and phylogenetic diversity, we selected Faith’s phylogenetic diversity (PD) index...

Direct and Indirect Effects of Climate Change on Amphibian Populations

OpenAIRE

Blaustein, Andrew R.; Walls, Susan C.; Bancroft, Betsy A.; Lawler, Joshua J.; Searle, Catherine L.; Gervasi, Stephanie S.

2010-01-01

As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth...

Trends in amphibian occupancy in the United States

Science.gov (United States)

Adams, Michael J.; Miller, David A.W.; Muths, Erin; Corn, Paul Stephen; Grant, Evan H. Campbell; Bailey, Larissa L.; Fellers, Gary M.; Fisher, Robert N.; Sadinski, Walter J.; Waddle, Hardin; Walls, Susan C.

2013-01-01

Though a third of amphibian species worldwide are thought to be imperiled, existing assessments simply categorize extinction risk, providing little information on the rate of population losses. We conducted the first analysis of the rate of change in the probability that amphibians occupy ponds and other comparable habitat features across the United States. We found that overall occupancy by amphibians declined 3.7% annually from 2002 to 2011. Species that are Red-listed by the International Union for Conservation of Nature (IUCN) declined an average of 11.6% annually. All subsets of data examined had a declining trend including species in the IUCN Least Concern category. This analysis suggests that amphibian declines may be more widespread and severe than previously realized.

Trends in amphibian occupancy in the United States.

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Michael J Adams

Full Text Available Though a third of amphibian species worldwide are thought to be imperiled, existing assessments simply categorize extinction risk, providing little information on the rate of population losses. We conducted the first analysis of the rate of change in the probability that amphibians occupy ponds and other comparable habitat features across the United States. We found that overall occupancy by amphibians declined 3.7% annually from 2002 to 2011. Species that are Red-listed by the International Union for Conservation of Nature (IUCN declined an average of 11.6% annually. All subsets of data examined had a declining trend including species in the IUCN Least Concern category. This analysis suggests that amphibian declines may be more widespread and severe than previously realized.

Status and trends of amphibian declines and extinctions worldwide.

Science.gov (United States)

Stuart, Simon N; Chanson, Janice S; Cox, Neil A; Young, Bruce E; Rodrigues, Ana S L; Fischman, Debra L; Waller, Robert W

2004-12-03

The first global assessment of amphibians provides new context for the well-publicized phenomenon of amphibian declines. Amphibians are more threatened and are declining more rapidly than either birds or mammals. Although many declines are due to habitat loss and overutilization, other, unidentified processes threaten 48% of rapidly declining species and are driving species most quickly to extinction. Declines are nonrandom in terms of species' ecological preferences, geographic ranges, and taxonomic associations and are most prevalent among Neotropical montane, stream-associated species. The lack of conservation remedies for these poorly understood declines means that hundreds of amphibian species now face extinction.

Amphibian Population Sensitivity to Environmental and ...

Science.gov (United States)

Anticipating chronic effects of contaminant exposure on amphibian species is complicated both by toxicological and ecological uncertainty. Data for both chemical exposures and amphibian vital rates, including altered growth, are sparse. Developmental plasticity in amphibians further complicates evaluation of chemical impacts as metamorphosis is also influenced by other biotic and abiotic stressors, such as temperature, hydroperiod, predation, and conspecific density. Determining the effect of delayed tadpole development on survival through metamorphosis and subsequent recruitment must include possible effects of pond drying accelerating metamorphosis near the end of the larval stage. This model considers the combined influence of delayed onset of metamorphosis in a cohort as well as accelerated metamorphosis toward the end of the hydroperiod and determines the net influence of counteracting forces on tadpole development and survival. Amphibian populations with greater initial density dependence have less capacity for developmental plasticity and are therefore more vulnerable to delayed development and reduced hydroperiod. The consequential reduction in larval survival has a relatively greater impact on species with a shorter lifespan, allowing for fewer breeding seasons during which to successfully produce offspring. In response to risk assessment approaches that consider only survival and reproductive endpoints in population evaluation, we calculate conta

Restored agricultural wetlands in Central Iowa: habitat quality and amphibian response

Science.gov (United States)

Reeves, Rebecca A.; Pierce, Clay; Smalling, Kelly L.; Klaver, Robert W.; Vandever, Mark W.; Battaglin, William A.; Muths, Erin L.

2016-01-01

Amphibians are declining throughout the United States and worldwide due, partly, to habitat loss. Conservation practices on the landscape restore wetlands to denitrify tile drainage effluent and restore ecosystem services. Understanding how water quality, hydroperiod, predation, and disease affect amphibians in restored wetlands is central to maintaining healthy amphibian populations in the region. We examined the quality of amphibian habitat in restored wetlands relative to reference wetlands by comparing species richness, developmental stress, and adult leopard frog (Lithobates pipiens) survival probabilities to a suite of environmental metrics. Although measured habitat variables differed between restored and reference wetlands, differences appeared to have sub-lethal rather than lethal effects on resident amphibian populations. There were few differences in amphibian species richness and no difference in estimated survival probabilities between wetland types. Restored wetlands had more nitrate and alkaline pH, longer hydroperiods, and were deeper, whereas reference wetlands had more amphibian chytrid fungus zoospores in water samples and resident amphibians exhibited increased developmental stress. Restored and reference wetlands are both important components of the landscape in central Iowa and maintaining a complex of fish-free wetlands with a variety of hydroperiods will likely contribute to the persistence of amphibians in this landscape.

Red List of amphibians and reptiles of the Wadden Sea area

Science.gov (United States)

Fog, K.; Podloucky, R.; Dierking, U.; Stumpel, A. H. P.

1996-10-01

In the Wadden Sea, in total, 8 species of amphibians and 4 species of reptiles are threatened in at least one subregion. Of these, 7 species of amphibians and all 4 species of reptiles are threatened in the entire area and are therefore placed on the trilateral Red List. 1 species of the listed reptiles is (probably) extinct in the entire Wadden Sea area. The status of 1 species of amphibians is endangered, the status of (probably) 4 species of amphibians and 3 species of reptiles are vulnerable and of 2 species of amphibians susceptible.

Invasive and introduced reptiles and amphibians: Chapter 28

Science.gov (United States)

Reed, Robert N.; Krysko, Kenneth L.; Mader, Douglas R.; Divers, Stephen J.

2014-01-01

Why is there a section on introduced amphibians and reptiles in this volume, and why should veterinarians care about this issue? Globally, invasive species are a major threat to the stability of native ecosystems,1,2 and amphibians and reptiles are attracting increased attention as potential invaders. Some introduced amphibians and reptiles have had a major impact (e.g., Brown Tree Snakes [Boiga irregularis] wiping out the native birds of Guam3 or Cane Toads [Rhinella marina] poisoning native Australian predators).4 For the vast majority of species, however, the ecological, economic, and sociopolitical effects of introduced amphibians and reptiles are generally poorly quantified, largely because of a lack of focused research effort rather than because such effects are nonexistent. This trend is alarming given that rates of introduction have increased exponentially in recent decades.

Ecotoxicology of Amphibians and Reptiles

Science.gov (United States)

2000-01-01

For many years, ecological research on amphibians and reptiles has lagged behind that of other vertebrates such as fishes, birds, and mammals, despite the known importance of these animals in their environments. The lack of study has been particularly acute in the he area of ecotoxicology where the number of published scientific papers is a fraction of that found for the other vertebrate classes. Recently, scientists have become aware of severe crises among amphibian populations, including unexplained and sudden extinctions, worldwide declines, and hideous malformations. In many of these instances, contaminants have been listed as probable contributors. Data on the effects of contaminants on reptiles are so depauperate that even the most elementary interpretations are difficult. This state-of-the-science review and synthesis of amphibian and reptile ecotoxicology demonstrates the inter-relationships among distribution, ecology, physiology, and contaminant exposure, and interprets these topics as they pertain to comparative toxicity, population declines, malformations, and risk assessment . In this way, the book identifies and serves as a basis for the most pressing research needs in the coming years. The editors have invited 27 other internationally respected experts to examine the state of existing data in specific areas, interpret it in light of current problems, and identify research gaps and needs. Through its emphasis on recent research, extensive reviews and synthesis, Ecotoxicology of Amphibians and Reptiles will remain a definitive reference work well into the new century.

Developments in amphibian captive breeding and reintroduction programs.

Science.gov (United States)

Harding, Gemma; Griffiths, Richard A; Pavajeau, Lissette

2016-04-01

Captive breeding and reintroduction remain high profile but controversial conservation interventions. It is important to understand how such programs develop and respond to strategic conservation initiatives. We analyzed the contribution to conservation made by amphibian captive breeding and reintroduction since the launch of the International Union for Conservation of Nature (IUCN) Amphibian Conservation Action Plan (ACAP) in 2007. We assembled data on amphibian captive breeding and reintroduction from a variety of sources including the Amphibian Ark database and the IUCN Red List. We also carried out systematic searches of Web of Science, JSTOR, and Google Scholar for relevant literature. Relative to data collected from 1966 to 2006, the number of species involved in captive breeding and reintroduction projects increased by 57% in the 7 years since release of the ACAP. However, there have been relatively few new reintroductions over this period; most programs have focused on securing captive-assurance populations (i.e., species taken into captivity as a precaution against extinctions in the wild) and conservation-related research. There has been a shift to a broader representation of frogs, salamanders, and caecilians within programs and an increasing emphasis on threatened species. There has been a relative increase of species in programs from Central and South America and the Caribbean, where amphibian biodiversity is high. About half of the programs involve zoos and aquaria with a similar proportion represented in specialist facilities run by governmental or nongovernmental agencies. Despite successful reintroduction often being regarded as the ultimate milestone for such programs, the irreversibility of many current threats to amphibians may make this an impractical goal. Instead, research on captive assurance populations may be needed to develop imaginative solutions to enable amphibians to survive alongside current, emerging, and future threats. © 2015

Amphibian populations in the terrestrial environment: Is there evidence of declines of terrestrial forest amphibians in northwestern California?

Science.gov (United States)

Hartwell H. Welsh Jr.; Gary M. Fellers; Amy J. Lind

2007-01-01

Amphibian declines have been documented worldwide; however the vast majority are species associated with aquatic habitats. Information on the status and trends of terrestrial amphibians is almost entirely lacking. Here we use data collected across a 12-yr period (sampling from 1984–86 and from 1993–95) to address the question of whether evidence exists for declines...

Vulnerability of amphibians to climate change: implications for rangeland management

Science.gov (United States)

Karen E. Bagne; Deborah M. Finch; Megan M. Friggens

2011-01-01

Many amphibian populations have declined drastically in recent years due to a large number of factors including the emerging threat of climate change (Wake 2007). Rangelands provide important habitat for amphibians. In addition to natural wetlands, stock tanks and other artificial water catchments provide habitat for many amphibian species (Euliss et al. 2004).

Possibilties of using amphibians and reptiles to indicate environmental pollution

Energy Technology Data Exchange (ETDEWEB)

Petrov, V.S.; Sharygin, S.A.

1981-01-01

Data on the presence of certain toxic elements in organisms of amphibians and reptiles are reported. Differences in chemical composition of organisms of amphibians and reptiles living in wild biotopes and in settlements are shown. Analysis of microelement concentration in organisms of amphibians and reptiles can be used to detect pollution in urban areas.

Sperm motility of externally fertilizing fish and amphibians.

Science.gov (United States)

Browne, R K; Kaurova, S A; Uteshev, V K; Shishova, N V; McGinnity, D; Figiel, C R; Mansour, N; Agney, D; Wu, M; Gakhova, E N; Dzyuba, B; Cosson, J

2015-01-01

We review the phylogeny, sperm competition, morphology, physiology, and fertilization environments of the sperm of externally fertilizing fish and amphibians. Increased sperm competition in both fish and anurans generally increases sperm numbers, sperm length, and energy reserves. The difference between the internal osmolarity and iconicity of sperm cells and those of the aquatic medium control the activation, longevity, and velocity of sperm motility. Hypo-osmolarity of the aquatic medium activates the motility of freshwater fish and amphibian sperm and hyperosmolarity activates the motility of marine fish sperm. The average longevity of the motility of marine fish sperm (~550 seconds) was significantly (P amphibian sperm in general and anurans reversion from internal to external fertilization. Our findings provide a greater understanding of the reproductive biology of externally fertilizing fish and amphibians, and a biological foundation for the further development of reproduction technologies for their sustainable management.

First parasitological study of the African clawed frog (Xenopus laevis, Amphibia in Chile

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Cristóbal Castillo

Full Text Available Abstract Introduced species can arrive into new territories with parasites; however, these species are expected to face lower parasite richness than in their original regions. Both introduced hosts and parasites can affect native fauna. Since their release into the wild in Chile following laboratory use, Xenopus laevis Daudin, 1802 has widely spread throughout central Chile. The only pathogen described on the host is the fungus Batrachochytrium dendrobatidis Longcore, Pessier, Nichols, 1999; thus, this is the first parasitological study of this species in Chile. In 10 localities in central Chile, 179 specimens of X. laevis were captured and examined for parasites in the gastrointestinal tube, cavities, lungs, liver, and skin. Only nine specimens of the genus Contracaecum Railliet, Henry, 1912 were found in six specimens of X. laevis from a private dam in La Patagua. It is likely that these parasites originated from species of native birds. This is the first record of Contracaecum sp. in Chilean amphibians.

Microhabitat use and spatial distribution in Picado’s Bromeliad Treefrog, Isthmohyla picadoi (Anura, Hylidae

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Adam M. M. Stuckert

2009-12-01

Full Text Available Isthmohyla picadoi is a Neotropical hylid frog found in upper humid montane forests of Costa Rica and Panama. The species is of particular interest because it continues to persist in an area in which the amphibian community has otherwise been decimated by the pathogenic fungus, Batrachochytrium dendrobatidis. Ground search, ladder climbing, and tree climbing techniques were used to locate 32 individuals; including adult males and females, juveniles, andmetamorphosing frogs. The majority of frogs were found in bromeliads, although some individuals were found on plants of the Euphorbiaceae, Musaceae, and Heliconiaceae families. Most frogs were found in larger bromeliads (45 cm or wider. There was a positive correlation between SUL and bromeliad width within the population but not within maturity classes (adult males, adult females, all adults, nonmetamorphosingjuveniles, suggesting that juvenile and adult frogs differ in bromeliad usage. Ranges of SUL and body weight in this particular population are much greater than those reported in previous species accounts.

Gridded Species Distribution, Version 1: Global Amphibians Presence Grids

Data.gov (United States)

National Aeronautics and Space Administration — The Global Amphibians Presence Grids of the Gridded Species Distribution, Version 1 is a reclassified version of the original grids of amphibian species distribution...

Amphibians of the northern Great Plains

Science.gov (United States)

Larson, Diane L.; Euliss, Ned H.; Lannoo, Michael J.; Mushet, David M.; Mac, M.J.; Opler, P.A.; Puckett Haecker, C. E.; Doran, P.D.

1998-01-01

No cry of alarm has been sounded over the fate of amphibian populations in the northern grasslands of North America, yet huge percentages of prairie wetland habitat have been lost, and the destruction continues. Scarcely 30% of the original mixedgrass prairie remains in Nebraska, South Dakota, and North Dakota (See Table 1 in this chapter). If amphibian populations haven’t declined, why haven’t they? Or, have we simply failed to notice? Amphibians in the northern grasslands evolved in a boom-or-bust environment: species that were unable to survive droughts lasting for years died out long before humans were around to count them. Species we find today are expert at seizing the rare, wet moment to rebuild their populations in preparation for the next dry season. When numbers can change so rapidly, who can say if a species is rare or common? A lot depends on when you look.

Reptiles and Amphibians of Fairchild Air Force Base, WA

Science.gov (United States)

2013-05-10

Reptiles and Amphibians of Fairchild Air Force Base, WA C on st ru ct io n E n gi n ee ri n g R es ea rc...online library at http://acwc.sdp.sirsi.net/client/default. ERDC/CERL TR-13-5 May 2013 Reptiles and Amphibians of Fairchild Air Force Base, WA...Washington, DC 20314-1000 ERDC/CERL TR-13-5 ii Abstract Many reptile and amphibian (collectively termed “herpetofauna”) populations are declining at

Genome-wide transcriptional response of Silurana (Xenopus tropicalis to infection with the deadly chytrid fungus.

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Erica Bree Rosenblum

Full Text Available Emerging infectious diseases are of great concern for both wildlife and humans. Several highly virulent fungal pathogens have recently been discovered in natural populations, highlighting the need for a better understanding of fungal-vertebrate host-pathogen interactions. Because most fungal pathogens are not fatal in the absence of other predisposing conditions, host-pathogen dynamics for deadly fungal pathogens are of particular interest. The chytrid fungus Batrachochytrium dendrobatidis (hereafter Bd infects hundreds of species of frogs in the wild. It is found worldwide and is a significant contributor to the current global amphibian decline. However, the mechanism by which Bd causes death in amphibians, and the response of the host to Bd infection, remain largely unknown. Here we use whole-genome microarrays to monitor the transcriptional responses to Bd infection in the model frog species, Silurana (Xenopus tropicalis, which is susceptible to chytridiomycosis. To elucidate the immune response to Bd and evaluate the physiological effects of chytridiomycosis, we measured gene expression changes in several tissues (liver, skin, spleen following exposure to Bd. We detected a strong transcriptional response for genes involved in physiological processes that can help explain some clinical symptoms of chytridiomycosis at the organismal level. However, we detected surprisingly little evidence of an immune response to Bd exposure, suggesting that this susceptible species may not be mounting efficient innate and adaptive immune responses against Bd. The weak immune response may be partially explained by the thermal conditions of the experiment, which were optimal for Bd growth. However, many immune genes exhibited decreased expression in Bd-exposed frogs compared to control frogs, suggesting a more complex effect of Bd on the immune system than simple temperature-mediated immune suppression. This study generates important baseline data for ongoing

Climate change and amphibian diversity patterns in Mexico

DEFF Research Database (Denmark)

Ochoa-Ochoa, Leticia M.; Rodríguez, Pilar; Mora, Franz

2012-01-01

The aim of this article is to characterize at fine scale alpha and beta diversity patterns for Mexican amphibians and analyze how these patterns might change under a moderate climate-change scenario, highlighting the overall consequences for amphibian diversity at the country level. We used a geo...

Seasonal Variation in Population Abundance and Chytrid Infection in Stream-Dwelling Frogs of the Brazilian Atlantic Forest.

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Joice Ruggeri

Full Text Available Enigmatic amphibian declines were first reported in southern and southeastern Brazil in the late 1980s and included several species of stream-dwelling anurans (families Hylodidae and Cycloramphidae. At that time, we were unaware of the amphibian-killing fungus Batrachochytrium dendrobatidis (Bd; therefore, pollution, habitat loss, fragmentation and unusual climatic events were hypothesized as primary causes of these declines. We now know that multiple lineages of Bd have infected amphibians of the Brazilian Atlantic forest for over a century, yet declines have not been associated specifically with Bd outbreaks. Because stream-dwelling anurans occupy an environmental hotspot ideal for disease transmission, we investigated temporal variation in population and infection dynamics of three stream-adapted species (Hylodes asper, H. phyllodes, and Cycloramphus boraceiensis on the northern coast of São Paulo state, Brazil. We surveyed standardized transects along streams for four years, and show that fluctuations in the number of frogs correlate with specific climatic variables that also increase the likelihood of Bd infections. In addition, we found that Bd infection probability in C. boraceiensis, a nocturnal species, was significantly higher than in Hylodes spp., which are diurnal, suggesting that the nocturnal activity may either facilitate Bd zoospore transmission or increase susceptibility of hosts. Our findings indicate that, despite long-term persistence of Bd in Brazil, some hosts persist with seasonally variable infections, and thus future persistence in the face of climate change will depend on the relative effect of those changes on frog recruitment and pathogen proliferation.

Questions concerning the potential impact of glyphosate-based herbicides on amphibians.

Science.gov (United States)

Wagner, Norman; Reichenbecher, Wolfram; Teichmann, Hanka; Tappeser, Beatrix; Lötters, Stefan

2013-08-01

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. Copyright © 2013 SETAC.

Oral chytridiomycosis in the mountain yellow-legged frog (Rana muscosa)

Science.gov (United States)

Fellers, G.M.; Green, E.D.; Longcore, J.E.

2001-01-01

The chytrid fungus Batrachochytrium dendrobatidis was originally reported in wild frog populations in Panama and Australia, and from captive frogs in the U.S. National Zoological Park (Washington, DC). This recently described fungus affects the keratinized epidermis of amphibians and has been implicated as a causative factor in the declines of frog populations. We report here the presence of B. dendrobatidis in larval and recently metamorphosed mountain yellow-legged frogs (Rana muscosa) in or near the Sierra Nevada Mountains of California, an area where declines have been documented in all five species of native anurans. Forty-one percent (158 of 387) of larval R. muscosa examined in the field with a hand lens and 18% (14 of 79) of preserved larvae had abnormalities of the oral disc. Twenty-eight larvae were collected from 10 sites where tadpoles had been observed with missing or abnormally keratinized mouthparts, and 24 of these were examined for infection. Sixty-seven percent (16 of 24) of these tadpoles were infected with B. dendrobatidis. Batrachochytrium dendrobatidis was cultured from both tadpoles and recent metamorphs from one of these sites. Tadpoles with mouthpart abnormalities or confirmed chytrid fungus infections were collected at 23 sites spanning a distance of > 440 km and an elevational range from 1658-3550 m. Life-history traits of R. muscosa may make this species particularly susceptible to infection by Batrachochytrium. We recommend that biologists examine tadpoles for oral disc abnormalities as a preliminary indication of chytridiomycosis. Further, we believe that biologists should take precautions to prevent spreading this and other amphibian diseases from one site to another.

[Strategies for Conservation of Endangered Amphibian and Reptile Species].

Science.gov (United States)

Anan'eva, N B; Uteshev, V K; Orlova, N L; Gakhova, E N

2015-01-01

Strategies for conservation of endangered amphibian and reptile species are discussed. One-fifth of all vertebrates belongs to the category of "endangered species," and amphibians are first on the list (41%). Every fifth reptile species is in danger of extinction, and insufficient information is characteristic of every other fifth. As has been demonstrated, efficient development of a network of nature conservation areas, cryopreservation, and methods for laboratory breeding and reintroduction play.the key roles in adequate strategies for preservation of amphibians and reptiles.

Amphibian molecular ecology and how it has informed conservation.

Science.gov (United States)

McCartney-Melstad, Evan; Shaffer, H Bradley

2015-10-01

Molecular ecology has become one of the key tools in the modern conservationist's kit. Here we review three areas where molecular ecology has been applied to amphibian conservation: genes on landscapes, within-population processes, and genes that matter. We summarize relevant analytical methods, recent important studies from the amphibian literature, and conservation implications for each section. Finally, we include five in-depth examples of how molecular ecology has been successfully applied to specific amphibian systems. © 2015 John Wiley & Sons Ltd.

An alternative framework for responding to the amphibian crisis

Science.gov (United States)

Muths, Erin L.; Fisher, Robert N.

2017-01-01

Volumes of data illustrate the severity of the crisis affecting amphibians, where > 32% of amphibians worldwide are threatened with declining populations. Although there have been isolated victories, the current approach to the issue is unsuccessful. We suggest that a radically different approach, something akin to human emergency response management (i.e. the Incident Command System), is one alternative to addressing the inertia and lack of cohesion in responding to amphibian issues. We acknowledge existing efforts and the useful research that has been conducted, but we suggest that a change is warranted and that the identification of a new amphibian chytrid provides the impetus for such a change. Our goal is to recognize that without a centralized effort we (collectively) are likely to fail in responding to this challenge.

Amphibian monitoring in the Atchafalaya Basin

Science.gov (United States)

Waddle, Hardin

2011-01-01

Amphibians are a diverse group of animals that includes frogs, toads, and salamanders. They are adapted to living in a variety of habitats, but most require water for at least one life stage. Amphibians have recently become a worldwide conservation concern because of declines and extinctions even in remote protected areas previously thought to be safe from the pressures of habitat loss and degradation. Amphibians are an important part of ecosystem dynamics because they can be quite abundant and serve both as a predator of smaller organisms and as prey to a suite of vertebrate predators. Their permeable skin and aquatic life history also make them useful as indicators of ecosystem health. Since 2002, the U.S. Geological Survey has been studying the frog and toad species inhabiting the Atchafalaya Basin to monitor for population declines and to better understand how the species are potentially affected by disease, environmental contaminants, and climate change.

Pseudacris triseriata (western chorus frog) and Rana sylvatica (wood frog) chytridiomycosis

Science.gov (United States)

Rittman, S.E.; Muths, E.; Green, D.E.

2003-01-01

The chytrid fungus Batrachochytrium dendrobatidis is a known pathogen of anuran amphibians, and has been correlated with amphibian die-offs worldwide (Daszak et. al. 1999. Emerging Infectious Diseases 5:735-748). In Colorado, B. dendrobatidis has infected Boreal toads (Bufo boreas) (Muths et. al., in review) and has been identified on museum specimens of northern leopard frogs (Rana pipiens) (Carey et. al. 1999. Develop. Comp. Immunol. 23:459-472). We report the first verified case of chytrid fungus in chorus frogs (Pseudacris triseriata) and wood frogs (Rana sylvatica) in the United States. We collected seven P. triseriata, and two adult and two juvenile R. sylvatica in the Kawuneeche Valley in Rocky Mountain National Park (RMNP) during June 2001. These animals were submitted to the National Wildlife Health Center (NWHC) as part of an amphibian health evaluation in RMNP. Chorus frogs were shipped in one container. Wood frog adults and juveniles were shipped in two separate containers. Histological examinations of all chorus frogs and 3 of 4 wood frogs were positive for chytrid fungus infection. The fourth (adult) wood frog was too decomposed for meaningful histology. Histological findings consisted of multifocally mild to diffusely severe infections of the epidermis of the ventrum and hindlimb digital skin. Chytrid thalli were confined to the thickened epidermis (hyperkeratosis), were spherical to oval, and occasional thalli contained characteristic discharge pores or zoospores (Green and Kagarise Sherman 1999. J. Herpetol 35:92-103; Fellers et al. 2001. Copeia 2001:945-953). We cannot confirm that all specimens carried the fungus at collection, because infection may have spread from one individual to all other individuals in each container during transport. Further sampling of amphibians in Kawuneeche Valley is warranted to determine the rate of infection and mortality in these populations.

Widespread occurrence of bd in French Guiana, South America.

Directory of Open Access Journals (Sweden)

Elodie A Courtois

Full Text Available The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd is a purported agent of decline and extinction of many amphibian populations worldwide. Its occurrence remains poorly documented in many tropical regions, including the Guiana Shield, despite the area's high amphibian diversity. We conducted a comprehensive assessment of Bd in French Guiana in order to (1 determine its geographical distribution, (2 test variation of Bd prevalence among species in French Guiana and compare it to earlier reported values in other South American anuran species (http://www.bd-maps.net; 123 species from 15 genera to define sentinel species for future work, (3 track changes in prevalence through time and (4 determine if Bd presence had a negative effect on one selected species. We tested the presence of Bd in 14 species at 11 sites for a total of 1053 samples (306 in 2009 and 747 in 2012. At least one Bd-positive individual was found at eight out of 11 sites, suggesting a wide distribution of Bd in French Guiana. The pathogen was not uniformly distributed among the studied amphibian hosts, with Dendrobatidae species displaying the highest prevalence (12.4% as compared to Bufonidae (2.6 % and Hylidae (1.5%. In contrast to earlier reported values, we found highest prevalence for three Dendrobatidae species and two of them displayed an increase in Bd prevalence from 2009 to 2012. Those three species might be the sentinel species of choice for French Guiana. For Dendrobates tinctorius, of key conservation value in the Guiana Shield, smaller female individuals were more likely to be infected, suggesting either that frogs can outgrow their chytrid infections or that the disease induces developmental stress limiting growth. Generally, our study supports the idea that Bd is more widespread than previously thought and occurs at remote places in the lowland forest of the Guiana shield.

Female sexual arousal in amphibians.

Science.gov (United States)

Wilczynski, Walter; Lynch, Kathleen S

2011-05-01

Rather than being a static, species specific trait, reproductive behavior in female amphibians is variable within an individual during the breeding season when females are capable of reproductive activity. Changes in receptivity coincide with changes in circulating estrogen. Estrogen is highest at the point when females are ready to choose a male and lay eggs. At this time female receptivity (her probability of responding to a male vocal signal) is highest and her selectivity among conspecific calls (measured by her probability of responding to a degraded or otherwise usually unattractive male signal) is lowest. These changes occur even though females retain the ability to discriminate different acoustic characteristics of various conspecific calls. After releasing her eggs, female amphibians quickly become less receptive and more choosy in terms of their responses to male sexual advertisement signals. Male vocal signals stimulate both behavior and estrogen changes in amphibian females making mating more probable. The changes in female reproductive behavior are the same as those generally accepted as indicative of a change in female sexual arousal leading to copulation. They are situationally triggered, gated by interactions with males, and decline with the consummation of sexual reproduction with a chosen male. The changes can be triggered by either internal physiological state or by the presence of stimuli presented by males, and the same stimuli change both behavior and physiological (endocrine) state in such a way as to make acceptance of a male more likely. Thus amphibian females demonstrate many of the same general characteristics of changing female sexual state that in mammals indicate sexual arousal. Copyright © 2010 Elsevier Inc. All rights reserved.

All about Amphibians. Animal Life for Children. [Videotape].

Science.gov (United States)

2000

This videotape teaches children about their favorite amphibious creatures, as well as amphibians' nearest cousins--toads, newts, and salamanders. Young students discover how these amazing creatures can live both in and out of water, learn about the amphibious life cycle, and compare the differences between amphibians and reptiles. This videotape…

A Place to Call Home: Amphibian Use of Created and Restored Wetlands

OpenAIRE

Brown, Donald J.; Street, Garrett M.; Nairn, Robert W.; Forstner, Michael R. J.

2012-01-01

Loss and degradation of wetland habitats are major contributing factors to the global decline of amphibians. Creation and restoration of wetlands could be a valuable tool for increasing local amphibian species richness and abundance. We synthesized the peer-reviewed literature addressing amphibian use of created and restored wetlands, focusing on aquatic habitat, upland habitat, and wetland connectivity and configuration. Amphibian species richness or abundance at created and restored wetland...

Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar

Science.gov (United States)

Bletz, Molly C.; Archer, Holly; Harris, Reid N.; McKenzie, Valerie J.; Rabemananjara, Falitiana C. E.; Rakotoarison, Andolalao; Vences, Miguel

2017-01-01

Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs) and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation) explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae) was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae) was enriched on aquatic frogs, and Agrobacterium (Rhizobiaceae

Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar

Directory of Open Access Journals (Sweden)

Molly C. Bletz

2017-08-01

Full Text Available Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae was enriched on aquatic frogs, and Agrobacterium

Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar.

Science.gov (United States)

Bletz, Molly C; Archer, Holly; Harris, Reid N; McKenzie, Valerie J; Rabemananjara, Falitiana C E; Rakotoarison, Andolalao; Vences, Miguel

2017-01-01

Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs) and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation) explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae) was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae) was enriched on aquatic frogs, and Agrobacterium (Rhizobiaceae

Amphibian and reptile declines over 35 years at La Selva, Costa Rica.

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Whitfield, Steven M; Bell, Kristen E; Philippi, Thomas; Sasa, Mahmood; Bolaños, Federico; Chaves, Gerardo; Savage, Jay M; Donnelly, Maureen A

2007-05-15

Amphibians stand at the forefront of a global biodiversity crisis. More than one-third of amphibian species are globally threatened, and over 120 species have likely suffered global extinction since 1980. Most alarmingly, many rapid declines and extinctions are occurring in pristine sites lacking obvious adverse effects of human activities. The causes of these "enigmatic" declines remain highly contested. Still, lack of long-term data on amphibian populations severely limits our understanding of the distribution of amphibian declines, and therefore the ultimate causes of these declines. Here, we identify a systematic community-wide decline in populations of terrestrial amphibians at La Selva Biological Station, a protected old-growth lowland rainforest in lower Central America. We use data collected over 35 years to show that population density of all species of terrestrial amphibians has declined by approximately 75% since 1970, and we show identical trends for all species of common reptiles. The trends we identify are neither consistent with recent emergence of chytridiomycosis nor the climate-linked epidemic hypothesis, two leading putative causes of enigmatic amphibian declines. Instead, our data suggest that declines are due to climate-driven reductions in the quantity of standing leaf litter, a critical microhabitat for amphibians and reptiles in this assemblage. Our results raise further concerns about the global persistence of amphibian populations by identifying widespread declines in species and habitats that are not currently recognized as susceptible to such risks.

Amphibians and Reptiles from Paramakatoi and Kato, Guyana

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MacCulloch, Ross D.; Reynolds, Robert P.

2012-01-01

We report the herpetofauna of two neighboring upland locations in west-central Guyana. Twenty amphibian and 24 reptile species were collected. Only 40% of amphibians and 12.5% of reptiles were collected in both locations. This is one of the few collections made at upland (750–800 m) locations in the Guiana Shield.

Toxicity of road salt to Nova Scotia amphibians

International Nuclear Information System (INIS)

Collins, Sara J.; Russell, Ronald W.

2009-01-01

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC 50 ) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. - Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands

Perspectives from the Aldo Leopold Wilderness Research Institute: Amphibians and wilderness

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Corn, Paul Stephen

2001-01-01

The decline of amphibian species has emerged as a major global conservation issue in the last decade. Last year, the Department of the Interior (DOI) initiated a major national initiative to detect trends in amphibian populations and research the causes of declines. The program, conducted principally by the U.S. Geological Survey (USGS), emphasizes lands managed by DOI, but collaboration with the Forest Service is encouraged to increase the scope of inference about population trends. Although amphibians are not usually the first group of animals that comes to mind when one thinks of wilderness, conservation of amphibian populations is clearly a wilderness issue.

Spatial Biodiversity Patterns of Madagascar's Amphibians and Reptiles.

Science.gov (United States)

Brown, Jason L; Sillero, Neftali; Glaw, Frank; Bora, Parfait; Vieites, David R; Vences, Miguel

2016-01-01

Madagascar has become a model region for testing hypotheses of species diversification and biogeography, and many studies have focused on its diverse and highly endemic herpetofauna. Here we combine species distribution models of a near-complete set of species of reptiles and amphibians known from the island with body size data and a tabulation of herpetofaunal communities from field surveys, compiled up to 2008. Though taxonomic revisions and novel distributional records arose since compilation, we are confident that the data are appropriate for inferring and comparing biogeographic patterns among these groups of organisms. We observed species richness of both amphibians and reptiles was highest in the humid rainforest biome of eastern Madagascar, but reptiles also show areas of high richness in the dry and subarid western biomes. In several amphibian subclades, especially within the Mantellidae, species richness peaks in the central eastern geographic regions while in reptiles different subclades differ distinctly in their richness centers. A high proportion of clades and subclades of both amphibians and reptiles have a peak of local endemism in the topographically and bioclimatically diverse northern geographic regions. This northern area is roughly delimited by a diagonal spanning from 15.5°S on the east coast to ca. 15.0°S on the west coast. Amphibian diversity is highest at altitudes between 800-1200 m above sea-level whereas reptiles have their highest richness at low elevations, probably reflecting the comparatively large number of species specialized to the extended low-elevation areas in the dry and subarid biomes. We found that the range sizes of both amphibians and reptiles strongly correlated with body size, and differences between the two groups are explained by the larger body sizes of reptiles. However, snakes have larger range sizes than lizards which cannot be readily explained by their larger body sizes alone. Range filling, i.e., the amount of

Spatial Biodiversity Patterns of Madagascar's Amphibians and Reptiles

Science.gov (United States)

Brown, Jason L.; Sillero, Neftali; Glaw, Frank; Bora, Parfait; Vieites, David R.; Vences, Miguel

2016-01-01

Madagascar has become a model region for testing hypotheses of species diversification and biogeography, and many studies have focused on its diverse and highly endemic herpetofauna. Here we combine species distribution models of a near-complete set of species of reptiles and amphibians known from the island with body size data and a tabulation of herpetofaunal communities from field surveys, compiled up to 2008. Though taxonomic revisions and novel distributional records arose since compilation, we are confident that the data are appropriate for inferring and comparing biogeographic patterns among these groups of organisms. We observed species richness of both amphibians and reptiles was highest in the humid rainforest biome of eastern Madagascar, but reptiles also show areas of high richness in the dry and subarid western biomes. In several amphibian subclades, especially within the Mantellidae, species richness peaks in the central eastern geographic regions while in reptiles different subclades differ distinctly in their richness centers. A high proportion of clades and subclades of both amphibians and reptiles have a peak of local endemism in the topographically and bioclimatically diverse northern geographic regions. This northern area is roughly delimited by a diagonal spanning from 15.5°S on the east coast to ca. 15.0°S on the west coast. Amphibian diversity is highest at altitudes between 800–1200 m above sea-level whereas reptiles have their highest richness at low elevations, probably reflecting the comparatively large number of species specialized to the extended low-elevation areas in the dry and subarid biomes. We found that the range sizes of both amphibians and reptiles strongly correlated with body size, and differences between the two groups are explained by the larger body sizes of reptiles. However, snakes have larger range sizes than lizards which cannot be readily explained by their larger body sizes alone. Range filling, i.e., the amount

Control of respiration in fish, amphibians and reptiles

Directory of Open Access Journals (Sweden)

E.W. Taylor

Full Text Available Fish and amphibians utilise a suction/force pump to ventilate gills or lungs, with the respiratory muscles innervated by cranial nerves, while reptiles have a thoracic, aspiratory pump innervated by spinal nerves. However, fish can recruit a hypobranchial pump for active jaw occlusion during hypoxia, using feeding muscles innervated by anterior spinal nerves. This same pump is used to ventilate the air-breathing organ in air-breathing fishes. Some reptiles retain a buccal force pump for use during hypoxia or exercise. All vertebrates have respiratory rhythm generators (RRG located in the brainstem. In cyclostomes and possibly jawed fishes, this may comprise elements of the trigeminal nucleus, though in the latter group RRG neurons have been located in the reticular formation. In air-breathing fishes and amphibians, there may be separate RRG for gill and lung ventilation. There is some evidence for multiple RRG in reptiles. Both amphibians and reptiles show episodic breathing patterns that may be centrally generated, though they do respond to changes in oxygen supply. Fish and larval amphibians have chemoreceptors sensitive to oxygen partial pressure located on the gills. Hypoxia induces increased ventilation and a reflex bradycardia and may trigger aquatic surface respiration or air-breathing, though these latter activities also respond to behavioural cues. Adult amphibians and reptiles have peripheral chemoreceptors located on the carotid arteries and central chemoreceptors sensitive to blood carbon dioxide levels. Lung perfusion may be regulated by cardiac shunting and lung ventilation stimulates lung stretch receptors.

Control of respiration in fish, amphibians and reptiles.

Science.gov (United States)

Taylor, E W; Leite, C A C; McKenzie, D J; Wang, T

2010-05-01

Fish and amphibians utilise a suction/force pump to ventilate gills or lungs, with the respiratory muscles innervated by cranial nerves, while reptiles have a thoracic, aspiratory pump innervated by spinal nerves. However, fish can recruit a hypobranchial pump for active jaw occlusion during hypoxia, using feeding muscles innervated by anterior spinal nerves. This same pump is used to ventilate the air-breathing organ in air-breathing fishes. Some reptiles retain a buccal force pump for use during hypoxia or exercise. All vertebrates have respiratory rhythm generators (RRG) located in the brainstem. In cyclostomes and possibly jawed fishes, this may comprise elements of the trigeminal nucleus, though in the latter group RRG neurons have been located in the reticular formation. In air-breathing fishes and amphibians, there may be separate RRG for gill and lung ventilation. There is some evidence for multiple RRG in reptiles. Both amphibians and reptiles show episodic breathing patterns that may be centrally generated, though they do respond to changes in oxygen supply. Fish and larval amphibians have chemoreceptors sensitive to oxygen partial pressure located on the gills. Hypoxia induces increased ventilation and a reflex bradycardia and may trigger aquatic surface respiration or air-breathing, though these latter activities also respond to behavioural cues. Adult amphibians and reptiles have peripheral chemoreceptors located on the carotid arteries and central chemoreceptors sensitive to blood carbon dioxide levels. Lung perfusion may be regulated by cardiac shunting and lung ventilation stimulates lung stretch receptors.

Control of respiration in fish, amphibians and reptiles

Directory of Open Access Journals (Sweden)

E.W. Taylor

2010-05-01

Full Text Available Fish and amphibians utilise a suction/force pump to ventilate gills or lungs, with the respiratory muscles innervated by cranial nerves, while reptiles have a thoracic, aspiratory pump innervated by spinal nerves. However, fish can recruit a hypobranchial pump for active jaw occlusion during hypoxia, using feeding muscles innervated by anterior spinal nerves. This same pump is used to ventilate the air-breathing organ in air-breathing fishes. Some reptiles retain a buccal force pump for use during hypoxia or exercise. All vertebrates have respiratory rhythm generators (RRG located in the brainstem. In cyclostomes and possibly jawed fishes, this may comprise elements of the trigeminal nucleus, though in the latter group RRG neurons have been located in the reticular formation. In air-breathing fishes and amphibians, there may be separate RRG for gill and lung ventilation. There is some evidence for multiple RRG in reptiles. Both amphibians and reptiles show episodic breathing patterns that may be centrally generated, though they do respond to changes in oxygen supply. Fish and larval amphibians have chemoreceptors sensitive to oxygen partial pressure located on the gills. Hypoxia induces increased ventilation and a reflex bradycardia and may trigger aquatic surface respiration or air-breathing, though these latter activities also respond to behavioural cues. Adult amphibians and reptiles have peripheral chemoreceptors located on the carotid arteries and central chemoreceptors sensitive to blood carbon dioxide levels. Lung perfusion may be regulated by cardiac shunting and lung ventilation stimulates lung stretch receptors.

Helminth parasites of amphibians from a rainforest reserve in ...

African Journals Online (AJOL)

Contrary to the earlier assumption that monogeneans in Nigeria were preferentially parasites of amphibians in drier environments such as the savanna, this study has shown that these parasites also infect amphibians in highly humid environments such as the rainforest. Monogeneans recorded included Metapolystoma ...

Annual Report: 2014: Partners in Amphibian and Reptile Conservation (PARC)

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Weir, Linda A.; Nanjappa, P.; Apodaca, J.J.; Williams, J.

2015-01-01

Partners in Amphibian and Reptile Conservation (PARC) was established in 1999 to address the widespread declines, extinctions, and range reductions of amphibians and reptiles, with a focus on conservation of taxa and habitats in North America. Amphibians and reptiles are affected by a broad range of human activities, both as incidental effects of habitat alteration and direct effects from overexploitation; these animals are also burdened by humans attitudes – that amphibians and reptiles are either dangerous or of little environmental or economic value. However, PARC members understand these taxa are important parts of our natural and cultural heritage and they serve important roles in ecosystems throughout the world. With many amphibians and reptiles classified as threatened with extinction, conservation to ensure healthy populations of these animals has never been more important. As you will see herein, PARC’s 15th anniversary has been marked with major accomplishments and an ever-increasing momentum. With your help, PARC can continue to build on its successes and protect these vital species.

Amphibian decline: an integrated analysis of multiple stressor effects

Energy Technology Data Exchange (ETDEWEB)

Linder, G.; Krest, S.K.; Sparkling, D.W. (eds.)

2003-07-01

Environmental effects of stressors on amphibians have received increased attention but little is known about the effects of these stressors on amphibian populations. The workshop addressed this issue. The proceedings contain 15 chapters, two of which mention effects of coal combustion wastes. These are: Chapter 4: Chemical stressors, by J.H. Burkhart, J.R. Bidwell, D.J. Fort, S.R. Sheffield, and Chapter 8E: Anthropogenic activities producing sink habitats for amphibians in the local landscape: a case study of lethal and sublethal effects of coal combustion residues in the aquatic environment by C.L. Rose and W.A. Hopkins.

Citation rate and perceived subject bias in the amphibian-decline literature.

Science.gov (United States)

Ohmer, Michel E; Bishop, Phillip J

2011-02-01

As a result of global declines in amphibian populations, interest in the conservation of amphibians has grown. This growth has been fueled partially by the recent discovery of other potential causes of declines, including chytridiomycosis (the amphibian chytrid, an infectious disease) and climate change. It has been proposed that researchers have shifted their focus to these novel stressors and that other threats to amphibians, such as habitat loss, are not being studied in proportion to their potential effects. We tested the validity of this proposal by reviewing the literature on amphibian declines, categorizing the primary topic of articles within this literature (e.g., habitat loss or UV-B radiation) and comparing citation rates among articles on these topics and impact factors of journals in which the articles were published. From 1990 to 2009, the proportion of papers on habitat loss remained fairly constant, and although the number of papers on chytridiomycosis increased after the disease was described in 1998, the number of published papers on amphibian declines also increased. Nevertheless, papers on chytridiomycosis were more highly cited than papers not on chytridiomycosis and were published in journals with higher impact factors on average, which may indicate this research topic is more popular in the literature. Our results were not consistent with a shift in the research agenda on amphibians. We believe the perception of such a shift has been supported by the higher citation rates of papers on chytridiomycosis. ©2010 Society for Conservation Biology.

Amphibian diversity in Shimba Hills National Reserve, Kenya: A ...

African Journals Online (AJOL)

We present the first annotated amphibian checklist of Shimba Hills National Reserve (SHNR). The list comprises of 30 currently known amphibians (28 anurans and two caecilians), which includes 11 families and 15 genera. In addition, individual records per species, distribution in the reserve and brief remarks about the ...

Diversity and dynamics of amphibians in floodplain ecosystems of the Samara river

Directory of Open Access Journals (Sweden)

O. V. Zhukov

2015-04-01

Full Text Available High emphasis is placed on amphibian importance as a buffer system, which has inhibiting effect on technogenic transformation of biogeocoenoses. Issues of the animals’ use in biological restoration, ecological rehabilitation of technogenic landscapes and in bioindication of environmental conditions are covered. Сhange in any component of the ecosystem leads to changing of the whole ecosystem. Anuran amphibians are extremely vulnerable to harmful effects of many factors of natural and anthropogenic origin. That is why, the destruction of forests, draining of wetlands, global climate change, global and local environmental pollution lead to complete disappearance or drastic decrease in numbers of many species of amphibians, reduction and fragmentation of their habitats, increased diversity and overall proportion of morphological anomalies in the natural populations of this group of animals. Recent studies of morphological changes in amphibians are increasingly being used to assess the state of the natural state of their populations and quality of their environment. In the biogeocenoses which are in the conditions of transformation amphibians have a number of advantages relative to their activity, the rate of reproduction, and euribiont character. Practical recommendations on protection and enrichment of the regional herpetofauna are given. The impact of the number and species diversity of amphibians on forest ecosystems of the steppe Dnieperin various conditions is assessed. Parametric entropy factors, the coefficient of biodiversity helped to identify the dominant species of amphibians. Taking into account the influence of predictors, there is the possibility to determine the number and species diversity of amphibians in the conditions of floodplain lime-ash forest. As a result of recording, the following species were caught: Pelobates fuscus (Laurenti, 1768, Rana arvalis Nilsson, 1842, Bufo bufo (Linnaeus, 1758, Bombina bombina (Linnaeus, 1758

Uses and Doses of Local Anesthetics in Fish, Amphibians, and Reptiles.

Science.gov (United States)

Chatigny, Frederic; Kamunde, Collins; Creighton, Catherine M; Stevens, E Don

2017-05-01

Local anesthetics are an integral part of routine pain management in mammals, yet their use is relatively limited in fish, amphibians and reptiles. These animals frequently undergo potentially painful surgical procedures and therefore could possibly benefit from those drugs. Some recommendations are currently available in the literature concerning analgesic use in these animals. However the pharmacological properties, safety and often efficacy of local anesthetic drugs have not been investigated yet in fish, amphibians, or reptiles. This review compiled current information concerning the use of those agents in fish, reptiles and amphibians to help clinicians make an informed decision as to which dose and drug to use. The resulting literature search showed that the literature concerning use of local analgesics in fish and amphibians is very limited while the literature for reptiles is more extensive. We found few experimental studies evaluating the efficacy of local anesthetics. Further studies would provide additional information for developing guidelines to improve the welfare of fish, amphibians and reptiles.

Amphibians and Reptiles of Los Alamos County

Energy Technology Data Exchange (ETDEWEB)

Teralene S. Foxx; Timothy K. Haarmann; David C. Keller

1999-10-01

Recent studies have shown that amphibians and reptiles are good indicators of environmental health. They live in terrestrial and aquatic environments and are often the first animals to be affected by environmental change. This publication provides baseline information about amphibians and reptiles that are present on the Pajarito Plateau. Ten years of data collection and observations by researchers at Los Alamos National Laboratory, the University of New Mexico, the New Mexico Department of Game and Fish, and hobbyists are represented.

Conservation, duplication, and loss of the Tor signaling pathway in the fungal kingdom

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Heitman Joseph

2010-09-01

Full Text Available Abstract Background The nutrient-sensing Tor pathway governs cell growth and is conserved in nearly all eukaryotic organisms from unicellular yeasts to multicellular organisms, including humans. Tor is the target of the immunosuppressive drug rapamycin, which in complex with the prolyl isomerase FKBP12 inhibits Tor functions. Rapamycin is a gold standard drug for organ transplant recipients that was approved by the FDA in 1999 and is finding additional clinical indications as a chemotherapeutic and antiproliferative agent. Capitalizing on the plethora of recently sequenced genomes we have conducted comparative genomic studies to annotate the Tor pathway throughout the fungal kingdom and related unicellular opisthokonts, including Monosiga brevicollis, Salpingoeca rosetta, and Capsaspora owczarzaki. Results Interestingly, the Tor signaling cascade is absent in three microsporidian species with available genome sequences, the only known instance of a eukaryotic group lacking this conserved pathway. The microsporidia are obligate intracellular pathogens with highly reduced genomes, and we hypothesize that they lost the Tor pathway as they adapted and streamlined their genomes for intracellular growth in a nutrient-rich environment. Two TOR paralogs are present in several fungal species as a result of either a whole genome duplication or independent gene/segmental duplication events. One such event was identified in the amphibian pathogen Batrachochytrium dendrobatidis, a chytrid responsible for worldwide global amphibian declines and extinctions. Conclusions The repeated independent duplications of the TOR gene in the fungal kingdom might reflect selective pressure acting upon this kinase that populates two proteinaceous complexes with different cellular roles. These comparative genomic analyses illustrate the evolutionary trajectory of a central nutrient-sensing cascade that enables diverse eukaryotic organisms to respond to their natural

Do effects of mercury in larval amphibians persist after metamorphosis?

Science.gov (United States)

Todd, Brian D; Willson, John D; Bergeron, Christine M; Hopkins, William A

2012-01-01

Despite widespread concern about the role of environmental contaminants in global amphibian declines, and evidence that post-metamorphic life stages contribute disproportionately to amphibian population dynamics, most studies in amphibian ecotoxicology focus on larval life stages. Studies that focus solely on early life stages may miss important effects of contaminant exposure, such as latent effects that manifest some time after previous exposure. Moreover, it is often assumed that effects observed in amphibian larvae will persist to affect survival or reproduction later in life. We used terrestrial enclosures to determine whether exposure to mercury (Hg) through maternal transfer and/or larval diet had any adverse effects in post-metamorphic American toads (Bufo americanus). We found a 5% difference in size at metamorphosis that was attributed to maternal Hg exposure persisted for 1 year in the terrestrial environment, resulting in a 7% difference at the conclusion of the study. Although patterns of survival differed among treatments through time, we found no overall difference in survival after 1 year. We also found no evidence of emergent latent effects in the terrestrial toads that could be attributed to earlier exposure. Our results indicate that adverse effects of maternal Hg exposure that were observed in larval amphibians may persist to affect later terrestrial life stages but that no novel adverse effects developed when animals were raised in a semi-natural environment. Moreover, we found no evidence of persistent effects of dietary Hg exposure in larvae, highlighting a need for greater focus on maternal effects in amphibian ecotoxicology. Finally, we suggest an increase in the use of longitudinal studies to better understand contaminant impacts to amphibian populations via effects in both aquatic and terrestrial life stages.

New distributional records of amphibians and reptiles from northern Oaxaca, México

OpenAIRE

González, Cynthia; Brenis, Ángel; Arrazola, Teresa

2014-01-01

During 2011 we performed a microregional inventory of amphibians and reptiles from the south-central region of the Papaloapan basin in northern Oaxaca. We recorded one amphibian species previously unknown in the state, and recorded range extensions for two additional amphibian and four reptile species. This increases the known herpetofauna of Oaxaca to 378 species.

Does fire affect amphibians and reptiles in eastern U.S. oak forests?

Science.gov (United States)

Rochelle B. Renken

2006-01-01

Current information about the effect of fire on amphibians and reptiles in oak forests of the Eastern and Central United States is reviewed. Current data suggest that fire results in little direct mortality of amphibians and reptiles. Fire has no effect on overall amphibian abundance, diversity, and number of species in comparisons of burned and unburned plots, though...

Common procedures in reptiles and amphibians.

Science.gov (United States)

de la Navarre, Byron J S

2006-05-01

Reptiles and amphibians continue to be popular as pets in the United States and throughout the world. It therefore behooves veterinarians interested in caring for these exotic species to continually gather knowledge concerning both their proper husbandry and the conditions that require medical and/or surgical intervention. This article covers husbandry, physical examination, and clinical and diagnostic techniques in an effort to present guidelines for the evaluation of the reptile or amphibian patient. Gathering clinical data will aid veterinarians in arriving at the proper diagnosis,increasing the chances of success with treatment protocols, and educating the clients in proper nutrition and husbandry for their pets.

Effects of experimental canopy manipulation on amphibian egg deposition

Science.gov (United States)

Zachary I. Felix; Yong Wang; Callie J. Schweitzer

2010-01-01

Although effects of forest management on amphibians are relatively well studied, few studies have examined how these practices affect egg deposition by adults, which can impact population recruitment. We quantified the effects of 4 canopy tree-retention treatments on amphibian oviposition patterns in clusters of 60-L aquatic mesocosms located in each treatment. We also...

[Nested species subsets of amphibians and reptiles in Thousand Island Lake].

Science.gov (United States)

Wang, Xi; Wang, Yan-Ping; Ding, Ping

2012-10-01

Habitat fragmentation is a main cause for the loss of biological diversity. Combining line-transect methods to survey the amphibians and reptiles on 23 islands on Thousand Island Lake in Zhejiang province, along with survey data on nearby plant species and habitat variables collected by GIS, we used the"BINMATNEST (binary matrix nestedness temperature calculator)" software and the Spearman rank correlation to examine whether amphibians and reptiles followed nested subsets and their influencing factors. The results showed that amphibians and reptiles were significantly nested, and that the island area and habitat type were significantly associated with their nested ranks. Therefore, to effectively protect amphibians and reptiles in the Thousand Islands Lake area we should pay prior attention to islands with larger areas and more habitat types.

A Place to Call Home: Amphibian Use of Created and Restored Wetlands

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Donald J. Brown

2012-01-01

Full Text Available Loss and degradation of wetland habitats are major contributing factors to the global decline of amphibians. Creation and restoration of wetlands could be a valuable tool for increasing local amphibian species richness and abundance. We synthesized the peer-reviewed literature addressing amphibian use of created and restored wetlands, focusing on aquatic habitat, upland habitat, and wetland connectivity and configuration. Amphibian species richness or abundance at created and restored wetlands was either similar to or greater than reference wetlands in 89% of studies. Use of created and restored wetlands by individual species was driven by aquatic and terrestrial habitat preferences, as well as ability to disperse from source wetlands. We conclude that creating and restoring wetlands can be valuable tools for amphibian conservation. However, the ecological needs and preferences of target species must be considered to maximize the potential for successful colonization and long-term persistence.

Population dynamics of the critically endangered toad Atelopus cruciger and the fungal disease chytridiomycosis

Science.gov (United States)

Señaris, Celsa; García, Carmen Zulay

2017-01-01

Harlequin toads (Atelopus) are among the most severely impacted amphibians by the emergence of chytridiomycosis, a fungal disease caused by the pathogen Batrachochytrium dendrobatidis (Bd). Many species disappeared while others suffered drastic contractions of their geographic distribution to lower altitudes. A diminished virulence of Bd in warm habitats was proposed to explain the survival of lowland populations of harlequin toads (i.e. thermal refuge hypothesis). To understand the mechanisms that allow some populations to reach an endemic equilibrium with this pathogen, we estimated demographic and epidemiological parameters at one remnant population of Atelopus cruciger in Venezuela using mark-recapture data from 2007–2013. We demonstrated that Bd is highly virulent for A. cruciger, increasing the odds of dying of infected adults four times in relation to uninfected ones and reducing the life expectancy of reproductive toads to a few weeks. Despite an estimated annual loss of 18% of the reproductive population due to Bd-induced mortality, this population has persisted in an endemic equilibrium for the last decade through the large recruitment of healthy adults every year. Given the high vulnerability of harlequin toads to Bd in lowland populations, thermal refuges need to be redefined as habitats of reduced transmission rather than attenuated virulence. PMID:28570689

Measuring the meltdown: drivers of global amphibian extinction and decline.

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Navjot S Sodhi

Full Text Available Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545 or had increased (n = 28. These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

Measuring the meltdown: drivers of global amphibian extinction and decline.

Science.gov (United States)

Sodhi, Navjot S; Bickford, David; Diesmos, Arvin C; Lee, Tien Ming; Koh, Lian Pin; Brook, Barry W; Sekercioglu, Cagan H; Bradshaw, Corey J A

2008-02-20

Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

Advective and diffusive dermal processes for estimating terrestrial amphibian pesticide exposure

Science.gov (United States)

Background/Question/Methods Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Historically, evaluation of pesticide risk to both amphibians and reptiles has been achieved by comparing ingestion and inhalat...

Amphibians of the Simbruini Mountains (Latium, Central Italy

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Pierangelo Crucitti

2010-07-01

Full Text Available Little attention has been paid to the herpetological fauna of the Simbruini Mountains Regional Park, Latium (Central Italy. In this study, we surveyed 50 sites in the course of about ten years of field research, especially during the period 2005-2008. Nine amphibian species, four Caudata and five Anura, 60.0% out of the 15 amphibian species so far observed in Latium, were discovered in the protected area: Salamandra salamandra, Salamandrina perspicillata, Lissotriton vulgaris, Triturus carnifex, Bombina pachypus, Bufo balearicus, Bufo bufo, Rana dalmatina, Rana italica. Physiography of sites has been detailed together with potential threatening patterns. For each species the following topics have been discussed; ecology of sites, altitudinal distribution, phenology, sintopy. Salamandra salamandra and Bombina pachypus are at higher risk. The importance of the maintenance of artificial/natural water bodies for the conservation management of amphibian population of this territory is discussed.

Amphibians and Reptiles of the state of Nuevo Le?n, Mexico

OpenAIRE

Lemos-Espinal, Julio A.; Smith, Geoffrey R.; Cruz, Alexander

2016-01-01

Abstract We compiled a check list of the herpetofauna of Nuevo Le?n. We documented 132 species (23 amphibians, 109 reptiles), representing 30 families (11 amphibians, 19 reptiles) and 73 genera (17 amphibians, 56 reptiles). Only two species are endemic to Nuevo Le?n. Nuevo Le?n contains a relatively high richness of lizards in the genus Sceloporus . Overlap in the herpetofauna of Nuevo Le?n and states it borders is fairly extensive. Of 130 native species, 102 are considered species of Least C...

Amphibians and reptiles of the state of Coahuila, Mexico, with comparison with adjoining states

OpenAIRE

Lemos-Espinal, Julio A.; Smith, Geoffrey R.

2016-01-01

Abstract We compiled a checklist of the amphibians and reptiles of the state of Coahuila, Mexico. The list comprises 133 species (24 amphibians, 109 reptiles), representing 27 families (9 amphibians, 18 reptiles) and 65 genera (16 amphibians, 49 reptiles). Coahuila has a high richness of lizards in the genus Sceloporus . Coahuila has relatively few state endemics, but has several regional endemics. Overlap in the herpetofauna of Coahuila and bordering states is fairly extensive. Of the 132 sp...

Vast underestimation of Madagascar's biodiversity evidenced by an integrative amphibian inventory.

Science.gov (United States)

Vieites, David R; Wollenberg, Katharina C; Andreone, Franco; Köhler, Jörn; Glaw, Frank; Vences, Miguel

2009-05-19

Amphibians are in decline worldwide. However, their patterns of diversity, especially in the tropics, are not well understood, mainly because of incomplete information on taxonomy and distribution. We assess morphological, bioacoustic, and genetic variation of Madagascar's amphibians, one of the first near-complete taxon samplings from a biodiversity hotspot. Based on DNA sequences of 2,850 specimens sampled from over 170 localities, our analyses reveal an extreme proportion of amphibian diversity, projecting an almost 2-fold increase in species numbers from the currently described 244 species to a minimum of 373 and up to 465. This diversity is widespread geographically and across most major phylogenetic lineages except in a few previously well-studied genera, and is not restricted to morphologically cryptic clades. We classify the genealogical lineages in confirmed and unconfirmed candidate species or deeply divergent conspecific lineages based on concordance of genetic divergences with other characters. This integrative approach may be widely applicable to improve estimates of organismal diversity. Our results suggest that in Madagascar the spatial pattern of amphibian richness and endemism must be revisited, and current habitat destruction may be affecting more species than previously thought, in amphibians as well as in other animal groups. This case study suggests that worldwide tropical amphibian diversity is probably underestimated at an unprecedented level and stresses the need for integrated taxonomic surveys as a basis for prioritizing conservation efforts within biodiversity hotspots.

Impact of forestry practices at a landscape scale on the dynamics of amphibian populations.

Science.gov (United States)

Harper, Elizabeth B; Patrick, David A; Gibbs, James P

2015-12-01

Forest loss is a primary cause of worldwide amphibian decline. Timber harvesting in the United States has caused dramatic changes in quality and extent of forest ecosystems, and intensive forest management still occurs. Although numerous studies have documented substantial reductions in amphibian densities related to timber harvest, subsequent extinctions are rare. To better understand the population dynamics that have allowed so many amphibian species to persist in the face of widespread forest disturbance, we developed spatially explicit metapopulation models for four forest-dependent amphibian species (Lithobates sylvaticus, Ambystoma opacum, A. talpoideum, and A. maculatum) that incorporated demographic and habitat selection data derived from experiments conducted as part of the Land Use Effects on Amphibian Populations Project (LEAP). We projected local and landscape-scale population persistence under 108 different forestry practice scenarios, varying treatment (partial cut, clear-cut with coarse woody debris [CWD] removed, and clearcut with CWD retained), cut patch size (1, 10, or 50 ha), total area cut (10, 20, or 30%), and initial amphibian population size (5, 50, or 500 adult females per local breeding population). Under these scenarios, landscape-scale extinction was highly unlikely, occurring in amphibian populations in the United States should focus not on questions of landscape-scale extinction but on the ecological consequences of dramatic reductions in amphibian biomass, including changes in trophic interactions, nutrient cycling, and energy transfer. Additionally, we conclude that amphibian declines and extinctions are far more likely to occur as a result of permanent habitat loss resulting from development than from the temporary degradation of habitat caused by current forestry practices.

The Maryland Amphibian and Reptile Atlas: A Volunteer-Based Distributional Survey

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Heather R. Cunningham

2012-01-01

Full Text Available Declines of amphibian and reptile populations are well documented. Yet a lack of understanding of their distribution may hinder conservation planning for these species. The Maryland Amphibian and Reptile Atlas project (MARA was launched in 2010. This five-year, citizen science project will document the distribution of the 93 amphibian and reptile species in Maryland. During the 2010 and 2011 field seasons, 488 registered MARA volunteers collected 13,919 occurrence records that document 85 of Maryland's amphibian and reptile species, including 19 frog, 20 salamander, five lizard, 25 snake, and 16 turtle species. Thirteen of these species are of conservation concern in Maryland. The MARA will establish a baseline by which future changes in the distribution of populations of native herpetofauna can be assessed as well as provide information for immediate management actions for rare and threatened species. As a citizen science project it has the added benefit of educating citizens about native amphibian and reptile diversity and its ecological benefits—an important step in creating an informed society that actively participates in the long-term conservation of Maryland's nature heritage.

Demonstration and Certification of Amphibian Ecological Risk Assessment Protocol

Science.gov (United States)

2009-04-01

pools observed on site persist through the breeding season and long enough for the larvae to metamorphose, suitable amphibian breeding habitat exists in...frog (R. palustris): vocalizations • Fairy shrimp (Eubranchipus sp.): dip net • Isopoda: dip net • Unknown water beetle (Coleoptera): dip net...oxygen-lacking) conditions that favor the growth and regeneration of hydrophytic vegetation)) to amphibians. This test procedure uses larvae of the

Climate warming and the decline of amphibians and reptiles in Europe

DEFF Research Database (Denmark)

Araújo, Miguel B.; Thuiller, W.; Pearson, R. G.

2006-01-01

deleterious than previously postulated; indeed, climate cooling would be more deleterious for the persistence of amphibian and reptile species than warming. The ability of species to cope with climate warming may, however, be offset by projected decreases in the availability of water. This should......-east are projected to gain suitable climate. This is because dry conditions in the south-west are projected to increase, approaching the levels found in North Africa, where few amphibian species are able to persist. Main conclusions The impact of increasing temperatures on amphibian and reptile species may be less...

Amphibians and plant-protection products: what research and action is needed?

Science.gov (United States)

Aldrich, Annette; Junghans, Marion; Aeberli, Caroline; Brühl, Carsten A; Streissl, Franz; Schmidt, Benedikt R

2016-01-01

The majority of Swiss amphibians are threatened. There is a range of factors which have been discussed as possible causes for their decline, including plant protection products (PPPs). The influence of PPPs on amphibian populations has not yet been studied to any great extent, neither for active ingredients nor for the wetting agents, breakdown products or tank mixtures. A further topic of discussion was how to better protect amphibians by reducing their exposure to PPPs in agricultural fields. Experts at a workshop concluded that further research is needed.

Helminth parasites of amphibians and reptiles from the Ucayali Region, Peru.

Science.gov (United States)

McAllister, Chris T; Bursey, Charles R; Freed, Paul S

2010-04-01

Twenty individual amphibians representing 9 species within 6 families and 44 individual reptiles representing 15 species within 8 families from the Ucayali Region, Peru, were examined for helminths. Seven (35%) of the amphibian species and 15 (34%) of the reptiles were found to harbor at least 1 species of helminth; 5 (25%) of the amphibians and 4 (9%) of the reptiles harbored multiple infections. A cyclophyllidean cestode and 14 taxa of nematodes within 7 families were found in the herpetofauna surveyed. Thirteen new host and 6 new geographic distribution records are documented.

Non-native fish introductions and the reversibility of amphibian declines in the Sierra Nevada

Science.gov (United States)

Roland A. Knapp

2004-01-01

Amphibians are declining worldwide for a variety of reasons, including habitat alteration, introduction of non-native species, disease, climate change, and environmental contaminants. Amphibians often play important roles in structuring ecosystems, and, as a result, amphibian population declines or extinctions are likely to affect other trophic levels (Matthews and...

Rainforest: Reptiles and Amphibians

Science.gov (United States)

Olson, Susanna

2006-01-01

Rainforest reptiles and amphibians are a vibrantly colored, multimedia art experience. To complete the entire project one may need to dedicate many class periods to production, yet in each aspect of the project a new and important skill, concept, or element is being taught or reinforced. This project incorporates the study of warm and cool color…

Sampling methods for amphibians in streams in the Pacific Northwest.

Science.gov (United States)

R. Bruce Bury; Paul Stephen. Corn

1991-01-01

Methods describing how to sample aquatic and semiaquatic amphibians in small streams and headwater habitats in the Pacific Northwest are presented. We developed a technique that samples 10-meter stretches of selected streams, which was adequate to detect presence or absence of amphibian species and provided sample sizes statistically sufficient to compare abundance of...

First case report on pathogenic fungus Fonsecaea sp. Negroni from skin of Pelophylax kl. esculentus L. in Serbia

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Stupar Miloš Č.

2017-01-01

Full Text Available Non-harmful adhesive tape method was applied directly on the skin surface of edible frog (Pelophylax kl. esculentus, captured in vernal ponds on the locality “Stevanove ravnice” within the Special Nature Reserve „Deliblatska peščara“, in order to detect fungal dwellers of frogs’ skin. Light microscopy analyses of Lactophenol Cotton Blue mounted adhesive tape samples taken from frog’s ventrum revealed the presence of melanized septate hyphae, branched conidiophores with chains of single-celled ovoid conidia, arising directly from the skin, which corresponds to morphological features of dematiaceous hyphomycete - Fonsecaea sp. Since members of genus Fonsecaea are frequently cited as causative agents of chromomycosis in amphibians, as well as human phaeohyphomycosis, world­wide, it is of great significance to study the presence of this fungal pathogen on amphibians in Serbia in order to make the basic reference data of the incidence of these pathogens in this region. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 173032

Fish kidney cells show higher tolerance to hyperosmolality than amphibian

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Lang Gui

2018-05-01

Full Text Available In contrast to fish, amphibians inhabit both aquatic and terrestrial environments. To better understand osmoregulation in fish and amphibian, we have investigated the morphological changes in kidney cells to osmotic stress. To address this, kidney cell line isolated from the freshwater grass carp (CIK and Chinese giant salamander (GSK were challenged to different mediums with distinct osmotic pressures (100, 300 and 700 mOsm. Morphological alterations of the fish and amphibian cells were compared by optical and electron microscopy. Following hyposmotic treatment (100 mOsm, both CIK and GSK cells became unhealthy and show condensed chromatin, swollen mitochondria and cytoplasmic vacuole. Meanwhile, after hyperosmotic treatment (700 mOsm, shrunken CIK cells with multipolar shape, pale or lightly stained cytoplasm, condensed chromatin, vacuoles and swollen mitochondria were detected. GSK cells were seriously damaged and most were completely lysed. The results suggest that fish kidney cells show a higher degree of tolerance to hyperosmoticity by comparing to amphibians and provide novel insights on the osmoregulatory capacity and adaptability of kidney cells between the two animal groups.

An unprecedented role reversal: ground beetle larvae (Coleoptera: Carabidae lure amphibians and prey upon them.

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Gil Wizen

Full Text Available Amphibians often feed on beetle larvae, including those of ground beetles (Carabidae. Preliminary reports have detailed an unusual trophic interaction in which, in contrast, larvae of the ground beetle Epomis prey upon juvenile and adult amphibians. While it is known that these larvae feed exclusively on amphibians, how the predator-prey encounter occurs to the advantage of the beetle larvae had been unknown to date. Using laboratory observations and controlled experiments, we recorded the feeding behavior of Epomis larvae, as well as the behavior of their amphibian prey. Here we reveal that larvae of two species of Epomis (E. circumscriptus and E. dejeani lure their potential predator, taking advantage of the amphibian's predation behavior. The Epomis larva combines a sit-and-wait strategy with unique movements of its antennae and mandibles to draw the attention of the amphibian to the presence of a potential prey. The intensity of this enticement increases with decreasing distance between the larva and the amphibian. When the amphibian attacks, the larva almost always manages to avoid the predator's protracted tongue, exploiting the opportunity to attach itself to the amphibian's body and initiate feeding. Our findings suggest that the trophic interaction between Epomis larvae and amphibians is one of the only natural cases of obligatory predator-prey role reversal. Moreover, this interaction involves a small insect larva that successfully lures and preys on a larger vertebrate. Such role reversal is exceptional in the animal world, extending our perspective of co-evolution in the arms race between predator and prey, and suggesting that counterattack defense behavior has evolved into predator-prey role reversal.

Understanding of the impact of chemicals on amphibians: a meta-analytic review.

Science.gov (United States)

Egea-Serrano, Andrés; Relyea, Rick A; Tejedo, Miguel; Torralva, Mar

2012-07-01

Many studies have assessed the impact of different pollutants on amphibians across a variety of experimental venues (laboratory, mesocosm, and enclosure conditions). Past reviews, using vote-counting methods, have described pollution as one of the major threats faced by amphibians. However, vote-counting methods lack strong statistical power, do not permit one to determine the magnitudes of effects, and do not compare responses among predefined groups. To address these challenges, we conducted a meta-analysis of experimental studies that measured the effects of different chemical pollutants (nitrogenous and phosphorous compounds, pesticides, road deicers, heavy metals, and other wastewater contaminants) at environmentally relevant concentrations on amphibian survival, mass, time to hatching, time to metamorphosis, and frequency of abnormalities. The overall effect size of pollutant exposure was a medium decrease in amphibian survival and mass and a large increase in abnormality frequency. This translates to a 14.3% decrease in survival, a 7.5% decrease in mass, and a 535% increase in abnormality frequency across all studies. In contrast, we found no overall effect of pollutants on time to hatching and time to metamorphosis. We also found that effect sizes differed among experimental venues and among types of pollutants, but we only detected weak differences among amphibian families. These results suggest that variation in sensitivity to contaminants is generally independent of phylogeny. Some publication bias (i.e., selective reporting) was detected, but only for mass and the interaction effect size among stressors. We conclude that the overall impact of pollution on amphibians is moderately to largely negative. This implies that pollutants at environmentally relevant concentrations pose an important threat to amphibians and may play a role in their present global decline.

Development of a mobile application for amphibian species recognition

International Nuclear Information System (INIS)

Parveen, B; Chew T H; Shamsir, M S; Ahmad, N

2014-01-01

The smartphones mobility and its pervasiveness are beginning to transform practices in biodiversity conservation. The integrated functionalities of a smartphone have created for the public and biodiversity specialists means to identify, gather and record biodiversity data while simultaneously creating knowledge portability in the digital forms of mobile guides. Smartphones enable beginners to recreate the delight of species identification usually reserved for specialist with years of experience. Currently, the advent of Android platform has enabled stakeholders in biodiversity to harness the ubiquity of this platform and create various types of mobile application or ''apps'' for use in biodiversity research and conservation. However, there is an apparent lack of application devoted to the identification in herpetofauna or amphibian science. Amphibians are a large class of animals with many different species still unidentified under this category. Here we describe the development of an app called Amphibian Recognition Android Application (ARAA) to identify frog amphibian species as well as an accompanying field guide. The app has the amphibian taxonomic key which assists the users in easy and rapid species identification, thus facilitating the process of identification and recording of species occurrences in conservation work. We will also present an overview of the application work flow and how it is designed to meet the needs a conservationist. As this application is still in its beta phase, further research is required to improve the application to include tools such automatic geolocation and geotagging, participative sensing via crowdsourcing and automated identification via image capture. We believe that the introduction of this app will create an impetus to the awareness of nature via species identification

Development of a mobile application for amphibian species recognition

Science.gov (United States)

Parveen, B.; H, Chew T.; Shamsir, M. S.; Ahmad, N.

2014-02-01

The smartphones mobility and its pervasiveness are beginning to transform practices in biodiversity conservation. The integrated functionalities of a smartphone have created for the public and biodiversity specialists means to identify, gather and record biodiversity data while simultaneously creating knowledge portability in the digital forms of mobile guides. Smartphones enable beginners to recreate the delight of species identification usually reserved for specialist with years of experience. Currently, the advent of Android platform has enabled stakeholders in biodiversity to harness the ubiquity of this platform and create various types of mobile application or "apps" for use in biodiversity research and conservation. However, there is an apparent lack of application devoted to the identification in herpetofauna or amphibian science. Amphibians are a large class of animals with many different species still unidentified under this category. Here we describe the development of an app called Amphibian Recognition Android Application (ARAA) to identify frog amphibian species as well as an accompanying field guide. The app has the amphibian taxonomic key which assists the users in easy and rapid species identification, thus facilitating the process of identification and recording of species occurrences in conservation work. We will also present an overview of the application work flow and how it is designed to meet the needs a conservationist. As this application is still in its beta phase, further research is required to improve the application to include tools such automatic geolocation and geotagging, participative sensing via crowdsourcing and automated identification via image capture. We believe that the introduction of this app will create an impetus to the awareness of nature via species identification.

A test of the substitution-habitat hypothesis in amphibians.

Science.gov (United States)

Martínez-Abraín, Alejandro; Galán, Pedro

2017-12-08

Most examples that support the substitution-habitat hypothesis (human-made habitats act as substitutes of original habitat) deal with birds and mammals. We tested this hypothesis in 14 amphibians by using percentage occupancy as a proxy of habitat quality (i.e., higher occupancy percentages indicate higher quality). We classified water body types as original habitat (no or little human influence) depending on anatomical, behavioral, or physiological adaptations of each amphibian species. Ten species had relatively high probabilities (0.16-0.28) of occurrence in original habitat, moderate probability of occurrence in substitution habitats (0.11-0.14), and low probability of occurrence in refuge habitats (0.05-0.08). Thus, the substitution-habitat hypothesis only partially applies to amphibians because the low occupancy of refuges could be due to the negligible human persecution of this group (indicating good conservation status). However, low occupancy of refuges could also be due to low tolerance of refuge conditions, which could have led to selective extinction or colonization problems due to poor dispersal capabilities. That original habitats had the highest probabilities of occupancy suggests amphibians have a good conservation status in the region. They also appeared highly adaptable to anthropogenic substitution habitats. © 2017 Society for Conservation Biology.

Risk assessment considerations for plant protection products and terrestrial life-stages of amphibians.

Science.gov (United States)

Weltje, Lennart; Ufer, Andreas; Hamer, Mick; Sowig, Peter; Demmig, Sandra; Dechet, Friedrich

2018-04-28

Some amphibians occur in agricultural landscapes during certain periods of their life cycle and consequently might be exposed to plant protection products (PPPs). While the sensitivity of aquatic life-stages is considered to be covered by the standard assessment for aquatic organisms (especially fish), the situation is less clear for terrestrial amphibian life-stages. In this paper, considerations are presented on how a risk assessment for PPPs and terrestrial life-stages of amphibians could be conducted. It discusses available information concerning the toxicity of PPPs to terrestrial amphibians, and their potential exposure to PPPs in consideration of aspects of amphibian biology. The emphasis is on avoiding additional vertebrate testing as much as possible by using exposure-driven approaches and by making use of existing vertebrate toxicity data, where appropriate. Options for toxicity testing and risk assessment are presented in a flowchart as a tiered approach, progressing from a non-testing approach, to simple worst-case laboratory testing, to extended laboratory testing, to semi-field enclosure tests and ultimately to full-scale field testing and monitoring. Suggestions are made for triggers to progress to higher tiers. Also, mitigation options to reduce the potential for exposure of terrestrial life-stages of amphibians to PPPs, if a risk were identified, are discussed. Finally, remaining uncertainties and research needs are considered by proposing a way forward (road map) for generating additional information to inform terrestrial amphibian risk assessment. Copyright © 2018 Elsevier B.V. All rights reserved.

Can myxosporean parasites compromise fish and amphibian reproduction?

Science.gov (United States)

Sitjà-Bobadilla, Ariadna

2009-08-22

Research into fish and amphibian reproduction has increased exponentially in recent years owing to the expansion of the aquaculture industry, the need to recover fishery populations, the impact of endocrine disruptors on the aquatic environment and the global decline of amphibian populations. This review focuses on a group of parasites, the Myxozoa, that affect fish and amphibian reproduction. Lists of the myxosporeans that specifically infect gonads are provided. Most of these are parasitic of freshwater hosts, and most amphibian cases are reported from testes. Sex specificity and sex reversal are discussed in relation to gonadal parasitism. The immune response of the fish to the infection is described, and the contribution of the immunoprivilege of gonads to host invasion is emphasized. The pathological effect of these parasites can be significant, especially in aquacultured broodstocks, on some occasions, leading to parasitic castration. Although myxosporean parasites are currently not very frequent in gonads, their impact could increase in the future owing to the transactions in the global market. Their easy release into the aquatic environment with spawning could make their spreading even more feasible. In the absence of commercial drugs or vaccines to treat and prevent these infections, there is an urgent need to develop specific, rapid and reliable diagnostic tools to control and manage animal movements. In addition, much effort is still to be made on deciphering the life cycle of these organisms, their invasion strategies and their immune evasion mechanisms.

Mitogenomic perspectives on the origin and phylogeny of living amphibians.

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Zhang, Peng; Zhou, Hui; Chen, Yue-Qin; Liu, Yi-Fei; Qu, Liang-Hu

2005-06-01

Establishing the relationships among modern amphibians (lissamphibians) and their ancient relatives is necessary for our understanding of early tetrapod evolution. However, the phylogeny is still intractable because of the highly specialized anatomy and poor fossil record of lissamphibians. Paleobiologists are still not sure whether lissamphibians are monophyletic or polyphyletic, and which ancient group (temnospondyls or lepospondyls) is most closely related to them. In an attempt to address these problems, eight mitochondrial genomes of living amphibians were determined and compared with previously published amphibian sequences. A comprehensive molecular phylogenetic analysis of nucleotide sequences yields a highly resolved tree congruent with the traditional hypotheses (Batrachia). By using a molecular clock-independent approach for inferring dating information from molecular phylogenies, we present here the first molecular timescale for lissamphibian evolution, which suggests that lissamphibians first emerged about 330 million years ago. By observing the fit between molecular and fossil times, we suggest that the temnospondyl-origin hypothesis for lissamphibians is more credible than other hypotheses. Moreover, under this timescale, the potential geographic origins of the main living amphibian groups are discussed: (i) advanced frogs (neobatrachians) may possess an Africa-India origin; (ii) salamanders may have originated in east Asia; (iii) the tropic forest of the Triassic Pangaea may be the place of origin for the ancient caecilians. An accurate phylogeny with divergence times can be also helpful to direct the search for "missing" fossils, and can benefit comparative studies of amphibian evolution.

Evaluation of episodic acidification and amphibian declines in the Rocky Mountains

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Frank A. Vertucci; Paul Stephen Corn

1996-01-01

We define criteria for documenting episodic acidification of amphibian breeding habitats and examine whether episodic acidification is responsible for observed declines of amphibian populations in the Rocky Mountains. Anthropogenic episodic acidification, caused by atmospheric deposition of sulfate and nitrate, occurs when the concentration of acid anions increases...

Assessing the links among environmental contaminants, endocrinology, and parasites to understand amphibian declines in montane regions of Costa Rica.

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Leary, Christopher J; Ralicki, Hannah F; Laurencio, David; Crocker-Buta, Sarah; Malone, John H

2018-01-01

Amphibians inhabiting montane riparian zones in the Neotropics are particularly vulnerable to decline, but the reasons are poorly understood. Because environmental contaminants, endocrine disruption, and pathogens often figure prominently in amphibian declines it is imperative that we understand how these factors are potentially interrelated to affect montane populations. One possibility is that increased precipitation associated with global warming promotes the deposition of contaminants in montane regions. Increased exposure to contaminants, in turn, potentially elicits chronic elevations in circulating stress hormones that could contribute to montane population declines by compromising resistance to pathogens and/or production of sex steroids regulating reproduction. Here, we test this hypothesis by examining contaminant levels, stress and sex steroid levels, and nematode abundances in male drab treefrogs, Smilisca sordida, from lowland and montane populations in Costa Rica. We found no evidence that montane populations were more likely to possess contaminants (i.e., organochlorine, organophosphate and carbamate pesticides or benzidine and chlorophenoxy herbicides) than lowland populations. We also found no evidence of elevational differences in circulating levels of the stress hormone corticosterone, estradiol or progesterone. However, montane populations possessed lower androgen levels, hosted more nematode species, and had higher nematode abundances than lowland populations. Although these results suggested that nematodes contributed to lower androgens in montane populations, we were unable to detect a significant inverse relationship between nematode abundance and androgen level. Our results suggest that montane populations of this species are not at greater risk of exposure to contaminants or chronic stress, but implicate nematodes and compromised sex steroid levels as potential threats to montane populations.

Assessing the links among environmental contaminants, endocrinology, and parasites to understand amphibian declines in montane regions of Costa Rica.

Directory of Open Access Journals (Sweden)

Christopher J Leary

Full Text Available Amphibians inhabiting montane riparian zones in the Neotropics are particularly vulnerable to decline, but the reasons are poorly understood. Because environmental contaminants, endocrine disruption, and pathogens often figure prominently in amphibian declines it is imperative that we understand how these factors are potentially interrelated to affect montane populations. One possibility is that increased precipitation associated with global warming promotes the deposition of contaminants in montane regions. Increased exposure to contaminants, in turn, potentially elicits chronic elevations in circulating stress hormones that could contribute to montane population declines by compromising resistance to pathogens and/or production of sex steroids regulating reproduction. Here, we test this hypothesis by examining contaminant levels, stress and sex steroid levels, and nematode abundances in male drab treefrogs, Smilisca sordida, from lowland and montane populations in Costa Rica. We found no evidence that montane populations were more likely to possess contaminants (i.e., organochlorine, organophosphate and carbamate pesticides or benzidine and chlorophenoxy herbicides than lowland populations. We also found no evidence of elevational differences in circulating levels of the stress hormone corticosterone, estradiol or progesterone. However, montane populations possessed lower androgen levels, hosted more nematode species, and had higher nematode abundances than lowland populations. Although these results suggested that nematodes contributed to lower androgens in montane populations, we were unable to detect a significant inverse relationship between nematode abundance and androgen level. Our results suggest that montane populations of this species are not at greater risk of exposure to contaminants or chronic stress, but implicate nematodes and compromised sex steroid levels as potential threats to montane populations.

What we know and don't know about amphibian declines in the West

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Corn, Paul Stephen

1994-01-01

The problem of declining amphibian species is thought to be particularly acute in western North America, but there are many gaps in our knowledge. Although several declines have been well-documented, other declines are anecdotal or hypothesized. Most documented declines are of ranid frogs or toads (Bufo). Species from montane habitats and those occurring in California have been best studied. Status of many desert species is unknown. Habitat destruction and introduced predators are the most common threats to amphibian populations. Some declines may represent natural variation in population size. Causes have not been determined for several cases where common species have declined over large areas. There are important considerations for ecosystem management, whether changes in amphibian populations are natural or caused by human activities. Causes for declines must be known so that management can be prescribed (or proscribed) to eliminate or minimize these causes. The natural variability of amphibian population numbers and the complexity of metapopulation structure emphasize the necessity of considering multiple temporal and spatial scales in ecosystem management. The decline of amphibian species throughout the world has received considerable recent attention (e.g., Blaustein and Wake 1990, Griffiths and Beebee 1992, Yoffe 1992). Much of this attention derives from a workshop held in February, 1990 on declining amphibians sponsored by the National Research Council Board (NRC) on Biology in Irvine, California (Barinaga 1990, Borchelt 1990). Because of media attention in the aftermath of this conference, it is a popular perception that amphibian declines are a new phenomenon that herpetologists have been slow to recognize (Griffiths and Beebee 1992, Quammen 1993). However, concern about amphibian populations in the United States dates back over 20 years. Beginning in the 1960s, a large, well-documented decline of northern leopard frogs (Rana pipiens) occurred in the

Has the time come for big science in wildlife health?

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Sleeman, Jonathan M.

2013-01-01

The consequences of wildlife emerging diseases are global and profound with increased burden on the public health system, negative impacts on the global economy, declines and extinctions of wildlife species, and subsequent loss of ecological integrity. Examples of health threats to wildlife include Batrachochytrium dendrobatidis, which causes a cutaneous fungal infection of amphibians and is linked to declines of amphibians globally; and the recently discovered Pseudogymnoascus (Geomyces) destructans, the etiologic agent of white nose syndrome which has caused precipitous declines of North American bat species. Of particular concern are the novel pathogens that have emerged as they are particularly devastating and challenging to manage. A big science approach to wildlife health research is needed if we are to make significant and enduring progress in managing these diseases. The advent of new analytical models and bench assays will provide us with the mathematical and molecular tools to identify and anticipate threats to wildlife, and understand the ecology and epidemiology of these diseases. Specifically, new molecular diagnostic techniques have opened up avenues for pathogen discovery, and the application of spatially referenced databases allows for risk assessments that can assist in targeting surveillance. Long-term, systematic collection of data for wildlife health and integration with other datasets is also essential. Multidisciplinary research programs should be expanded to increase our understanding of the drivers of emerging diseases and allow for the development of better disease prevention and management tools, such as vaccines. Finally, we need to create a National Fish and Wildlife Health Network that provides the operational framework (governance, policies, procedures, etc.) by which entities with a stake in wildlife health cooperate and collaborate to achieve optimal outcomes for human, animal, and ecosystem health.

Interactions between amphibians’ symbiotic bacteria cause the production of emergent anti-fungal metabolites

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Andrew Howard Loudon

2014-08-01

Full Text Available Amphibians possess beneficial skin bacteria that protect against the disease chytridiomycosis by producing secondary metabolites that inhibit the pathogen Batrachochytrium dendrobatidis (Bd. Metabolite production may be a mechanism of competition between bacterial species that results in host protection as a by-product. We expect that some co-cultures of bacterial species or strains will result in greater Bd inhibition than mono-cultures. To test this, we cultured four bacterial isolates (Bacillus sp., Janthinobacterium sp., Pseudomonas sp. and Chitinophaga arvensicola from red-backed salamanders (Plethodon cinereus and cultured isolates both alone and together to collect their cell-free supernatants (CFS. We challenged Bd with CFSs from four bacterial species in varying combinations. This resulted in three experimental treatments: 1 CFSs of single isolates; 2 combined CFSs of two isolates; and 3 CFSs from co-cultures. Pair-wise combinations of four bacterial isolates CFSs were assayed against Bd and revealed additive Bd inhibition in 42.2% of trials, synergistic inhibition in 42.2% and no effect in 16.6% of trials. When bacteria isolates were grown in co-cultures, complete Bd inhibition was generally observed, and synergistic inhibition occurred in four out of six trials. A metabolite profile of the most potent co-culture, Bacillus sp. and Chitinophaga arvensicola, was determined with LC-MS and compared with the profiles of each isolate in mono-culture. Emergent metabolites appearing in the co-culture were inhibitory to Bd, and the most potent inhibitor was identified as tryptophol. Thus mono-cultures of bacteria cultured from red-backed salamanders interacted synergistically and additively to inhibit Bd, and such bacteria produced emergent metabolites when cultured together, with even greater pathogen inhibition. Knowledge of how bacterial species interact to inhibit Bd can be used to select probiotics to provide amphibians with protection

Acute oral toxicity of chemicals in terrestrial life stages of amphibians: Comparisons to birds and mammals.

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Crane, Mark; Finnegan, Meaghean; Weltje, Lennart; Kosmala-Grzechnik, Sylwia; Gross, Melanie; Wheeler, James R

2016-10-01

Amphibians are currently the most threatened and rapidly declining group of vertebrates and this has raised concerns about their potential sensitivity and exposure to plant protection products and other chemicals. Current environmental risk assessment procedures rely on surrogate species (e.g. fish and birds) to cover the risk to aquatic and terrestrial life stages of amphibians, respectively. Whilst a recent meta-analysis has shown that in most cases amphibian aquatic life stages are less sensitive to chemicals than fish, little research has been conducted on the comparative sensitivity of terrestrial amphibian life stages. Therefore, in this paper we address the questions "What is the relative sensitivity of terrestrial amphibian life stages to acute chemical oral exposure when compared with mammals and birds?" and "Are there correlations between oral toxicity data for amphibians and data for mammals or birds?" Identifying a relationship between these data may help to avoid additional vertebrate testing. Acute oral amphibian toxicity data collected from the scientific literature and ecotoxicological databases were compared with toxicity data for mammals and birds. Toxicity data for terrestrial amphibian life stages are generally sparse, as noted in previous reviews. Single-dose oral toxicity data for terrestrial amphibian life stages were available for 26 chemicals and these were positively correlated with LD50 values for mammals, while no correlation was found for birds. Further, the data suggest that oral toxicity to terrestrial amphibian life stages is similar to or lower than that for mammals and birds, with a few exceptions. Thus, mammals or birds are considered adequate toxicity surrogates for use in the assessment of the oral exposure route in amphibians. However, there is a need for further data on a wider range of chemicals to explore the wider applicability of the current analyses and recommendations. Copyright © 2016 Elsevier Inc. All rights reserved.

Validity of fish, birds and mammals as surrogates for amphibians and reptiles in pesticide toxicity assessment.

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Ortiz-Santaliestra, Manuel E; Maia, Joao P; Egea-Serrano, Andrés; Lopes, Isabel

2018-02-28

Amphibians and reptiles are the two most endangered groups of vertebrates. Environmental pollution by pesticides is recognised as one of the major factors threatening populations of these groups. However, the effects of pesticides on amphibians and reptiles have been studied for few substances, which is partly related to the fact that these animals are not included in the mandatory toxicity testing conducted as part of environmental risk assessments of pesticides. Whether risks of pesticides to amphibians and reptiles are addressed by surrogate taxa used in risk assessment is currently under debate. In order to develop a scientifically sound and robust risk assessment scheme, information needs to be gathered to examine whether fish, birds and mammals are valid surrogates for amphibians and reptiles. We updated a systematic review of scientific literature that was recently published compiling toxicity data on amphibians and reptiles. The outcome of this review was analysed with the purposes to (1) compare endpoints from amphibians and reptiles with the available information from fish, birds and mammals, and (2) develop species sensitivity distributions (SSDs) for those substances tested in at least six amphibian species (no substances were found tested in at least six reptile species) to identify a candidate amphibian model species to be used as surrogate in risk assessment. A positive correlation was found between toxicity recorded on fish and amphibians, the former revealing, in general, to be more sensitive than the latter to waterborne pollutants. In the terrestrial environment, although birds and mammals were more sensitive than amphibians and reptiles to at least 60% of tested substances, just a few weak significant correlations were observed. As a general rule, homoeothermic vertebrates are not good surrogates for reptiles and terrestrial amphibians in pesticide risk assessment. However, some chemical-dependent trends were detected, with pyrethroids and

Global patterns of evolutionary distinct and globally endangered amphibians and mammals.

Science.gov (United States)

Safi, Kamran; Armour-Marshall, Katrina; Baillie, Jonathan E M; Isaac, Nick J B

2013-01-01

Conservation of phylogenetic diversity allows maximising evolutionary information preserved within fauna and flora. The "EDGE of Existence" programme is the first institutional conservation initiative that prioritises species based on phylogenetic information. Species are ranked in two ways: one according to their evolutionary distinctiveness (ED) and second, by including IUCN extinction status, their evolutionary distinctiveness and global endangerment (EDGE). Here, we describe the global patterns in the spatial distribution of priority ED and EDGE species, in order to identify conservation areas for mammalian and amphibian communities. In addition, we investigate whether environmental conditions can predict the observed spatial pattern in ED and EDGE globally. Priority zones with high concentrations of ED and EDGE scores were defined using two different methods. The overlap between mammal and amphibian zones was very small, reflecting the different phylo-biogeographic histories. Mammal ED zones were predominantly found on the African continent and the neotropical forests, whereas in amphibians, ED zones were concentrated in North America. Mammal EDGE zones were mainly in South-East Asia, southern Africa and Madagascar; for amphibians they were in central and south America. The spatial pattern of ED and EDGE was poorly described by a suite of environmental variables. Mapping the spatial distribution of ED and EDGE provides an important step towards identifying priority areas for the conservation of mammalian and amphibian phylogenetic diversity in the EDGE of existence programme.

The potential influence of environmental pollution on amphibian development and decline

Energy Technology Data Exchange (ETDEWEB)

Jung, R.E.

1996-12-31

Globally, amphibians are reportedly declining. Environmental pollution has been hypothesized to be associated with declines. Because of their aquatic development and permeable eggs, skin and gills, amphibians, like fishes, may be particularly susceptible to poor water quality or waterborne pollutants. This dissertation addresses effects of global pollutants such as pesticides, acid rain and associated metal toxicity, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and polychlorinated biphenyls (PCBs) on the development, behavior, and physiology of amphibian early life stages. This report contains only chapter six and conclusions. Chapter 6 reports on a field experiment in which green frogs from two clutches were exposed from egg to 107 days of age to water and sediments in enclosures along a PCB and metal contamination gradient in the Fox River and wetlands near Green Bay, Wisconsin. Green frogs showed lower hatching success and survival at sites with higher contaminant levels compared to cleaner wetland sites along Green Bay. Hatching success in the green frog was most significantly negatively correlated with sediment PCB levels. It can be concluded that environmental pollution and toxicants in aquatic environments can cause problems for amphibian early development. Sometimes the effects are subtle, and sometimes they are dramatic. In general, amphibian early life stages seem particularly sensitive to environmentally-realistic levels of low pH and metals, but appear more tolerant of TCDD and PCBs.

Applied reproductive technologies and genetic resource banking for amphibian conservation.

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Kouba, Andrew J; Vance, Carrie K

2009-01-01

As amphibian populations continue to decline, both government and non-government organisations are establishing captive assurance colonies to secure populations deemed at risk of extinction if left in the wild. For the most part, little is known about the nutritional ecology, reproductive biology or husbandry needs of the animals placed into captive breeding programs. Because of this lack of knowledge, conservation biologists are currently facing the difficult task of maintaining and reproducing these species. Academic and zoo scientists are beginning to examine different technologies for maintaining the genetic diversity of founder populations brought out of the wild before the animals become extinct from rapidly spreading epizootic diseases. One such technology is genetic resource banking and applied reproductive technologies for species that are difficult to reproduce reliably in captivity. Significant advances have been made in the last decade for amphibian assisted reproduction including the use of exogenous hormones for induction of spermiation and ovulation, in vitro fertilisation, short-term cold storage of gametes and long-term cryopreservation of spermatozoa. These scientific breakthroughs for a select few species will no doubt serve as models for future assisted breeding protocols and the increasing number of amphibians requiring conservation intervention. However, the development of specialised assisted breeding protocols that can be applied to many different families of amphibians will likely require species-specific modifications considering their wide range of reproductive modes. The purpose of this review is to summarise the current state of knowledge in the area of assisted reproduction technologies and gene banking for the conservation of amphibians.

Agrochemicals increase trematode infections in a declining amphibian species.

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Rohr, Jason R; Schotthoefer, Anna M; Raffel, Thomas R; Carrick, Hunter J; Halstead, Neal; Hoverman, Jason T; Johnson, Catherine M; Johnson, Lucinda B; Lieske, Camilla; Piwoni, Marvin D; Schoff, Patrick K; Beasley, Val R

2008-10-30

Global amphibian declines have often been attributed to disease, but ignorance of the relative importance and mode of action of potential drivers of infection has made it difficult to develop effective remediation. In a field study, here we show that the widely used herbicide, atrazine, was the best predictor (out of more than 240 plausible candidates) of the abundance of larval trematodes (parasitic flatworms) in the declining northern leopard frog Rana pipiens. The effects of atrazine were consistent across trematode taxa. The combination of atrazine and phosphate--principal agrochemicals in global corn and sorghum production--accounted for 74% of the variation in the abundance of these often debilitating larval trematodes (atrazine alone accounted for 51%). Analysis of field data supported a causal mechanism whereby both agrochemicals increase exposure and susceptibility to larval trematodes by augmenting snail intermediate hosts and suppressing amphibian immunity. A mesocosm experiment demonstrated that, relative to control tanks, atrazine tanks had immunosuppressed tadpoles, had significantly more attached algae and snails, and had tadpoles with elevated trematode loads, further supporting a causal relationship between atrazine and elevated trematode infections in amphibians. These results raise concerns about the role of atrazine and phosphate in amphibian declines, and illustrate the value of quantifying the relative importance of several possible drivers of disease risk while determining the mechanisms by which they facilitate disease emergence.

Amphibians and reptiles of South Ossetia

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Boris S. Tuniyev

2017-05-01

Full Text Available For the first time we have summarised the results of the study of batraho- and herpetofauna of the Republic of South Ossetia. We present an Annotated List of species as authentically living in the region, as well as ever mentioned for it in literature, field notebooks, museum collections and our own expeditions in South Ossetia. The batrachofauna of the Republic of South Ossetia counts nine species and the herpetofauna 19 species. It provides a complete inventory of all finds (65 localities. A number of confirmed species have been assigned for the first time in scientific literature for the territory of South Ossetia: Emys orbicularis, Darevskia mixta, Natrix megalocephala, Hierophis schmidti, Pelias dinniki, P. kaznakovi. We detected the morphological specificity of the South Ossetia' populations of Darevskia praticola, D. brauneri and D. caucasica. The Assessment of conservation status has been evaluated for all forms of amphibians and reptiles in the region. According to its results, five amphibian species and ten reptile species are recommended for inclusion into the Red Data Book of the Republic of South Ossetia. The central problem of environmental activities in the Region is the lack of a network of different rank protected areas covering all natural zones and altitudinal belts. The South Ossetian State Nature Reserve is the single protected area of South Ossetia, which provides protection only for three endangered species of amphibians and three species of reptiles.

Amphibians and reptiles of the state of Coahuila, Mexico, with comparison with adjoining states.

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Lemos-Espinal, Julio A; Smith, Geoffrey R

2016-01-01

We compiled a checklist of the amphibians and reptiles of the state of Coahuila, Mexico. The list comprises 133 species (24 amphibians, 109 reptiles), representing 27 families (9 amphibians, 18 reptiles) and 65 genera (16 amphibians, 49 reptiles). Coahuila has a high richness of lizards in the genus Sceloporus. Coahuila has relatively few state endemics, but has several regional endemics. Overlap in the herpetofauna of Coahuila and bordering states is fairly extensive. Of the 132 species of native amphibians and reptiles, eight are listed as Vulnerable, six as Near Threatened, and six as Endangered in the IUCN Red List. In the SEMARNAT listing, 19 species are Subject to Special Protection, 26 are Threatened, and three are in Danger of Extinction. Coahuila is home to several species of conservation concern, especially lizards and turtles. Coahuila is an important state for the conservation of the native regional fauna.

Rapid increases and time-lagged declines in amphibian occupancy after wildfire.

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Hossack, Blake R; Lowe, Winsor H; Corn, Paul Stephen

2013-02-01

Climate change is expected to increase the frequency and severity of drought and wildfire. Aquatic and moisture-sensitive species, such as amphibians, may be particularly vulnerable to these modified disturbance regimes because large wildfires often occur during extended droughts and thus may compound environmental threats. However, understanding of the effects of wildfires on amphibians in forests with long fire-return intervals is limited. Numerous stand-replacing wildfires have occurred since 1988 in Glacier National Park (Montana, U.S.A.), where we have conducted long-term monitoring of amphibians. We measured responses of 3 amphibian species to fires of different sizes, severity, and age in a small geographic area with uniform management. We used data from wetlands associated with 6 wildfires that burned between 1988 and 2003 to evaluate whether burn extent and severity and interactions between wildfire and wetland isolation affected the distribution of breeding populations. We measured responses with models that accounted for imperfect detection to estimate occupancy during prefire (0-4 years) and different postfire recovery periods. For the long-toed salamander (Ambystoma macrodactylum) and Columbia spotted frog (Rana luteiventris), occupancy was not affected for 6 years after wildfire. But 7-21 years after wildfire, occupancy for both species decreased ≥ 25% in areas where >50% of the forest within 500 m of wetlands burned. In contrast, occupancy of the boreal toad (Anaxyrus boreas) tripled in the 3 years after low-elevation forests burned. This increase in occupancy was followed by a gradual decline. Our results show that accounting for magnitude of change and time lags is critical to understanding population dynamics of amphibians after large disturbances. Our results also inform understanding of the potential threat of increases in wildfire frequency or severity to amphibians in the region. ©2012 Society for Conservation Biology.

Optimizing protection efforts for amphibian conservation in Mediterranean landscapes

Science.gov (United States)

García-Muñoz, Enrique; Ceacero, Francisco; Carretero, Miguel A.; Pedrajas-Pulido, Luis; Parra, Gema; Guerrero, Francisco

2013-05-01

Amphibians epitomize the modern biodiversity crisis, and attract great attention from the scientific community since a complex puzzle of factors has influence on their disappearance. However, these factors are multiple and spatially variable, and declining in each locality is due to a particular combination of causes. This study shows a suitable statistical procedure to determine threats to amphibian species in medium size administrative areas. For our study case, ten biological and ecological variables feasible to affect the survival of 15 amphibian species were categorized and reduced through Principal Component Analysis. The principal components extracted were related to ecological plasticity, reproductive potential, and specificity of breeding habitats. Finally, the factor scores of species were joined in a presence-absence matrix that gives us information to identify where and why conservation management are requires. In summary, this methodology provides the necessary information to maximize benefits of conservation measures in small areas by identifying which ecological factors need management efforts and where should we focus them on.

Amphibians and reptiles of the Calakmul Biosphere Reserve, México, with new records

OpenAIRE

Colston, Timothy; Barão-Nóbrega, José António; Manders, Ryan; Lett, Alice; Wilmott, Jamie; Cameron, Gavin; Hunter, Sidony; Radage, Adam; Littlefair, Etienne; Williams, Robert; Lopez Cen, Antonio; Slater, Kathy

2015-01-01

We provide a list of amphibians and reptiles of the Calakmul Biosphere Reserve in the southern half of the Mexican Yucatan, in the state of Campeche. The study area was sampled through opportunistic, transect and pitfall trap surveys conducted for three successive years. These surveys resulted in a total of 2,359 amphibian and reptile encounters, belonging to 20 amphibian and 69 reptile species from 24 total families. We present herein the records for one snake, one chelonian and two salamand...

The Current and Historical Distribution of Special Status Amphibians at the Livermore Site and Site 300

Energy Technology Data Exchange (ETDEWEB)

Hattem, M V; Paterson, L; Woollett, J

2008-08-20

65 surveys were completed in 2002 to assess the current distribution of special status amphibians at the Lawrence Livermore National Laboratory's (LLNL) Livermore Site and Site 300. Combined with historical information from previous years, the information presented herein illustrates the dynamic and probable risk that amphibian populations face at both sites. The Livermore Site is developed and in stark contrast to the mostly undeveloped Site 300. Yet both sites have significant issues threatening the long-term sustainability of their respective amphibian populations. Livermore Site amphibians are presented with a suite of challenges inherent of urban interfaces, most predictably the bullfrog (Rana catesbeiana), while Site 300's erosion issues and periodic feral pig (Sus scrofa) infestations reduce and threaten populations. The long-term sustainability of LLNL's special status amphibians will require active management and resource commitment to maintain and restore amphibian habitat at both sites.

The Effects of Ammonium Perchlorate on Reproduction and Development of Amphibians

Science.gov (United States)

2008-01-01

Mitigating Ammonium Perchlorate (AP) Exposure........................................................................18 Table 5-1. Funding History and...amphibian species were reared on perchlorate-laden food (e.g., hydroponically grown lettuce ) and their growth and development monitored. Thyroid...of Perchlorate Derived from Food Sources on Amphibian Development 8 Table 3.1 (Continued) 3.1 Initiate Lettuce Growth 3.2 Tests with Native

Long-term observations of Boreal Toads at an ARMI apex site

Science.gov (United States)

Corn, Paul Stephen; Muths, Erin L.; Pilliod, David S.

2011-01-01

The U.S. Geological Survey’s Amphibian Research and Monitoring Initiative (ARMI) is a national project with goals to monitor the status and trends of amphibians, conduct research on causes of declines, and provide information and support to management agencies for conservation of amphibian populations. ARMI activities are organized around extensive inventories and place-based monitoring (such as collaboration with the Greater Yellowstone Inventory and Monitoring Network), and intensive population studies and research at selected locations (apex sites). One such site is an oxbow pond on the Buffalo Fork near the Black Rock Ranger Station east of Grand Teton National Park. We have been conducting mark-recapture of boreal toads (Anaxyrus boreas) at Black Rock since 2002. In concert with studies of other toad populations in the Rocky Mountains, we have documented a high rate of incidence of the chytrid fungus Batrachochytrium dendrobatidis (Bd) and a negative rate of growth of the toad population, but not the population crash or extinction observed in other populations with high prevalence of Bd. Long-term observations at other ARMI apex sites have proven invaluable for studying effects of climate change on amphibian behavior, and the Black Rock site has been upgraded with onsite recording of weather data and auditory monitoring of other amphibian species. Continued research at Black Rock will be critical for understanding the interrelated effects of climate and disease on amphibians in the Greater Yellowstone Ecosystem.

Global patterns of evolutionary distinct and globally endangered amphibians and mammals.

Directory of Open Access Journals (Sweden)

Kamran Safi

Full Text Available BACKGROUND: Conservation of phylogenetic diversity allows maximising evolutionary information preserved within fauna and flora. The "EDGE of Existence" programme is the first institutional conservation initiative that prioritises species based on phylogenetic information. Species are ranked in two ways: one according to their evolutionary distinctiveness (ED and second, by including IUCN extinction status, their evolutionary distinctiveness and global endangerment (EDGE. Here, we describe the global patterns in the spatial distribution of priority ED and EDGE species, in order to identify conservation areas for mammalian and amphibian communities. In addition, we investigate whether environmental conditions can predict the observed spatial pattern in ED and EDGE globally. METHODS AND PRINCIPAL FINDINGS: Priority zones with high concentrations of ED and EDGE scores were defined using two different methods. The overlap between mammal and amphibian zones was very small, reflecting the different phylo-biogeographic histories. Mammal ED zones were predominantly found on the African continent and the neotropical forests, whereas in amphibians, ED zones were concentrated in North America. Mammal EDGE zones were mainly in South-East Asia, southern Africa and Madagascar; for amphibians they were in central and south America. The spatial pattern of ED and EDGE was poorly described by a suite of environmental variables. CONCLUSIONS: Mapping the spatial distribution of ED and EDGE provides an important step towards identifying priority areas for the conservation of mammalian and amphibian phylogenetic diversity in the EDGE of existence programme.

Joint effects of pesticides and ultraviolet-B radiation on amphibian larvae

International Nuclear Information System (INIS)

Yu, Shuangying; Wages, Mike; Willming, Morgan; Cobb, George P.; Maul, Jonathan D.

2015-01-01

A combination of multiple stressors may be linked to global amphibian declines. Of these, pesticides and UVB radiation co-exposures were examined on the African clawed frog (Xenopus laevis) to provide information that may be useful for amphibian conservation. The independent action model and inferential statistics were used to examine interactions between pesticides (malathion, endosulfan, α-cypermethrin, or chlorothalonil) and environmentally relevant UVB exposures. UVB radiation alone caused 35–68% mortality and nearly 100% of malformations. Pesticides and UVB had additive effects on larval mortality; however, several non-additive effects (antagonistic and synergistic interactions) were observed for total body length. Insecticides mainly affected axial development, whereas UVB radiation caused high incidence of edema, gut malformations, and abnormal tail tips. These results suggest that sublethal developmental endpoints were more sensitive for detecting joint effects. This work has implications for amphibian risk assessments for ecosystems where pesticides and high UVB radiation may co-occur. - Highlights: • Interactive effects of UVB radiation-pesticide co-exposures were examined in frogs. • UVB radiation alone caused 35–68% mortality and nearly 100% of malformations. • Pesticides and UVB had additive effects on larval mortality. • Several non-additive effects were observed for total body length. • Amphibian risk assessments should consider UVB radiation exposure as a co-stressor. - Possible interactions between pesticides and UVB radiation support the idea that amphibian risk assessments should consider these co-stressors when high UVB radiation exposure is high.

Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

Science.gov (United States)

Puglis, Holly J.; Boone, Michelle D.

2012-01-01

A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians. PMID:22761833

Speciation and zoogeography of amphibian in Sundaland

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Nia Kurniawan

2015-12-01

Full Text Available Sundaland is an interesting area to be explored based on its geological history, topography, and climate. Sundaland consists of Penisular Malaysia, Sumatra, Borneo, and Java which experienced some emergence and submergence process in the past. During 1981-2015, most of research in Sundaland found that amphibian family in Sundaland was dominated by Bufonidae, Ranidae, Microhylidae, Megophrydae, Rachophoridae, and Dicroglossidae which experienced lot of speciation in its history. Among of 4 major islands in Sundaland, Borneo has the highest number of species diversity, then Peninsular Malaysia, Sumatra, and Java. During those years, Sumatra and Java got least concern by researcher. Therefore, it is suggested for further study to explore more in Sumatra and Java. Keywords: Sundaland, amphibian, speciation, zoogeography.

Diversity and habitat preferences of amphibians and reptiles in Pakistan: a review

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Waqas Ali

2018-06-01

Full Text Available Geographical position of Pakistan is unique, and country harbors two out of six zoogeographical regions. The country can be divided into 15 habitat types in three major divisions: the mountainous region, foothills, and Indus plains. Overall, 219 species including 24 amphibians and 195 reptiles have been reported so far. Out of these, nine amphibian and 13 reptilian species are endemic to Pakistan. Despite this richness, there is paucity of knowledge regarding diversity of amphibians and reptiles as very few species have been thoroughly studied and very small area has been explored. This has led to the uncertainties regarding distribution and taxonomy of these taxa in the country. The herpetofauna is not protected by law in the country, and their conservation status is yet to be evaluated. Furthermore, distribution ranges of amphibians and reptiles have been changed and systemized survey work is required to update baseline information in the country.

Competency of reptiles and amphibians for eastern equine encephalitis virus.

Science.gov (United States)

White, Gregory; Ottendorfer, Christy; Graham, Sean; Unnasch, Thomas R

2011-09-01

Eastern equine encephalitis virus (EEEV) is endemic throughout most of the eastern United States. Although it is transmitted year round in Florida, transmission elsewhere is seasonal. The mechanism that enables EEEV to overwinter in seasonal foci remains obscure. In previous field studies, early season EEEV activity was detected in mosquito species that feed primarily upon ectothermic hosts, suggesting that reptiles and amphibians might represent overwintering reservoir hosts for EEEV. To determine if this might be possible, two commonly fed upon amphibian and reptile species were evaluated as hosts for the North American subtype I strain of EEEV. Neither amphibian species was a competent host. However, circulating viremias were detected in both reptile species examined. Hibernating infected garter snakes remained viremic after exiting hibernation. These data suggest that snakes may represent an overwintering host for North American EEEV.

Amphibian distribution patterns in western Europe

NARCIS (Netherlands)

Zuiderwijk, Annie

1980-01-01

Mechanisms controlling the distribution of amphibians in western Europe have been studied in France where related species, isolated from each other at least during the last glacial period, are now sympatric. Occurrences and biotope preferences of the various species were investigated in several

Factors contributing to amphibian road mortality in a wetland

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Haijun GU, Qiang DAI, Qian WANG, Yuezhao WANG

2011-12-01

Full Text Available To understand road characteristics and landscape features associated with high road mortality of amphibians in Zoige Wetland National Nature Reserve, we surveyed road mortality along four major roads after rainfall in May and September 2007. Road mortality of three species, Rana kukunoris, Nanorana pleskei and Bufo minshanicus, was surveyed across 225 transects (115 in May and 110 in September. Transects were 100 m long and repeated every two kilometers along the four major roads. We used model averaging to assess factors that might determine amphibian road mortality. We recorded an average of 24.6 amphibian road mortalities per kilometer in May and 19.2 in September. Among road characteristics, road width was positively associated with road morality for R. kukunori and B. minshanicus. Traffic volume also increased the road mortality of B. minshanicus in September. Of the landscape features measured, area proportions of three types of grassland (wet, mesic and dry within 1 km of the roads, particularly that of wet grassland, significantly increased road mortality for R. kukunori and total mortality across all three species. To most effectively reduce road mortality of amphibians in the Zoige wetlands, we suggest better road design such as avoiding wet grasslands, minimizing road width, underground passes and traffic control measures. The implementation of public transit in the area would reduce traffic volume, and hence mortality [Current Zoology 57 (6: 768–774, 2011].

Effects of Roads on Amphibian Populations

DEFF Research Database (Denmark)

Hels, T.

is the result of my three year PhD study at the National Environmental Research Institute, Kalø, and University of Copenhagen. Funded by NERI, the Danish Research Academy, and the Danish Road Directorate, it has dealt mainly with the effects of traffic and roads on amphibian populations. The Spadefoot toad...... of Spadefoot toads (Pelobates fuscus Laur.) II The effect of road kills on amphibian populations III Simulating viability of a Spadefoot toad (P. fuscus) metapopulation in a landscape fragmented by a road The manuscripts are preceded by a synopsis which sums up the work and puts it into a broader perspective......, Johan Elmberg, Andreas Seiler, and Per Sjögren-Gulve, for sharing your knowledge and enthusiasm for science with me. Constructive ideas, different approaches, and elaborate discussions are crucial parts of any scientific process: I thank Lenore Fahrig for dedicated and original teaching and discussions...

Riparian Habitat Management for Reptiles and Amphibians on Corps of Engineers Projects

National Research Council Canada - National Science Library

Dickerson, Dena

2001-01-01

... important taxonomic groups such as reptiles and amphibians. This note provides an overview of the importance of riparian habitat at Corps projects for reptiles and amphibians, identifies riparian zone functions and habitat characteristics, provides examples of representative taxa and regional comparisons, and describes impacts of riparian habitat modification.

Conserving Prairie Pothole Region wetlands and surrounding grasslands: evaluating effects on amphibians

Science.gov (United States)

Mushet, David M.; Neau, Jordan L.

2014-01-01

The maintenance of viable and genetically diverse populations of amphibians in the Prairie Pothole Region of the United States depends on upland as well as wetland over-wintering and landscape level habitat features.Prairie pothole wetlands provide important amphibian breeding habitat while grasslands surrounding these wetlands provide foraging habitat for adults, overwintering habitat for some species, and important connectivity among breeding wetlands.Grasslands surrounding wetlands were found to be especially important for wood frogs and northern leopard frogs, while croplands dominated habitat utilized by Great Plains toads and Woodhouse’s toads.Habitat suitability mapping highlighted (1) the influence of deep-water overwintering wetlands on suitable habitat for four of five anuran species encountered; (2) the lack of overlap between areas of core habitat for both the northern leopard frog and wood frog compared to the core habitat for both toad species; and (3) the importance of conservation programs in providing grassland components of northern leopard frog and wood frog habitat.Currently, there are approximately 7.2 million acres (2.9 million hectares, ha) of habitat in the PPR identified as suitable for amphibians. WRP and CRP wetland and grassland habitats accounted for approximately 1.9 million acres (0.75 million ha) or 26 percent of this total area.Continued loss of amphibian habitat resulting from an ongoing trend of returning PPR conservation lands to crop production, will likely have significant negative effects on the region’s ability to maintain amphibian biodiversity. Conversely, increases in conservation wetlands and surrounding grasslands on the PPR landscape have great potential to positively influence the region’s amphibian populations.

Ticks infesting amphibians and reptiles in Pernambuco, Northeastern Brazil.

Science.gov (United States)

Dantas-Torres, Filipe; Oliveira-Filho, Edmilson F; Soares, Fábio Angelo M; Souza, Bruno O F; Valença, Raul Baltazar P; Sá, Fabrício B

2008-01-01

Ticks infesting amphibians and reptiles in the State of Pernambuco are reviewed, based on the current literature and new collections recently carried out by the authors. To date, three tick species have been found on amphibians and reptiles in Pernambuco. Amblyomma fuscum appears to be exclusively associated with Boa constrictor, its type host. Amblyomma rotundatum has a relatively low host-specificity, being found on toads, snakes, and iguana. Amblyomma dissimile has been found on a lizard and also small mammals (i.e., rodents and marsupials). New tick-host associations and locality records are given.

Small Mammals, Reptiles, and Amphibians

Science.gov (United States)

Bryce Rickel

2005-01-01

This chapter focuses on small mammals, reptiles, and amphibians that inhabit the grasslands within the Southwestern Region of the USDA Forest Service. The chapter is not intended to be an all inclusive list of species, but rather to address the species that play important roles in grassland ecosystems and that often are associated with the management of grasslands....

Developmental responses of amphibians to solar and artificial UVB sources: a comparative study

International Nuclear Information System (INIS)

Hays, J.B.; Hoffman, P.D.; Pandelova, Iovanna; Coyle, Daniel

1996-01-01

Many amphibian species, in widely scattered locations, currently show population declines and/or reductions in range, but other amphibian species show no such declines. There is no known single cause for these declines. Differential sensitivity to UVB radiation among species might be one contributing factor. We have focused on amphibian eggs, potentially the most UVB-sensitive stage, and compared their resistance to UVB components of sunlight with their levels of photolyase, typically the most important enzyme for repair of the major UV photoproducts in DNA, cyclobutane pyrimidine dimers. (Author)

The Amphibian Research and Monitoring Initiative (ARMI): 5-year report

Science.gov (United States)

Muths, Erin; Gallant, Alisa L.; Campbell Grant, Evan H.; Battaglin, William A.; Green, David E.; Staiger, Jennifer S.; Walls, Susan C.; Gunzburger, Margaret S.; Kearney, Rick F.

2006-01-01

The Amphibian Research and Monitoring Initiative (ARMI) is an innovative, multidisciplinary program that began in 2000 in response to a congressional directive for the Department of the Interior to address the issue of amphibian declines in the United States. ARMI’s formulation was cross-disciplinary, integrating U.S. Geological Survey scientists from Biology, Water, and Geography to develop a course of action (Corn and others, 2005a). The result has been an effective program with diverse, yet complementary, expertise.

Initial diversification of living amphibians predated the breakup of Pangaea

OpenAIRE

San Mauro, D.; Vences, M.; Alcobendas, M.; Zardoya, R.; Meyer, A.

2005-01-01

The origin and divergence of the three living orders of amphibians (Anura, Caudata, Gymnophiona) and their main lineages are one of the most hotly debated topics in vertebrate evolution. Here, we present a robust molecular phylogeny based on the nuclear RAG1 gene as well as results from a variety of alternative independent molecular clock calibrations. Our analyses suggest that the origin and early divergence of the three living amphibian orders dates back to the Palaeozoic or early Mesozoic,...

Monitoring strategy for eight amphibian species in French Guiana, South America.

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Elodie A Courtois

Full Text Available Although dramatic amphibian declines have been documented worldwide, only few of such events have been quantitatively documented for the tropical forests of South America. This is due partly to the fact that tropical amphibians are patchily distributed and difficult to detect. We tested three methods often used to monitor population trends in amphibian species in a remote lowland tropical forest of French Guiana. These methods are capture-mark-recapture (CMR, estimation of the number of calling males with repeated counts data and distance sampling, and rates of occupancy inferred by presence/absence data. We monitored eight diurnal, terrestrial amphibian species including five Dendrobatidae and three Bufonidae. We found that CMR, the most precise way of estimating population size, can be used only with two species in high density patches where the recapture rate is high enough. Only for one of the species (Dendrobates tinctorius, a low coefficient of variation (CV = 0.19 can be achieved with 15 to 20 capture events. For dendrobatid species with day-calling males, audio surveys yield a better probability of detection with only 8 audio surveys needed; quantitative estimates can be achieved by computing the number of calling males inferred from audio counts or distance sampling analysis. We therefore suggest that an efficient monitoring protocol for Neotropical amphibian species should include a combination of sighting and audio techniques, and we discuss the need of implementing a large-scale monitoring in order to provide a baseline for comparison with future changes.

A statistical assessment of population trends for data deficient Mexican amphibians

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Esther Quintero

2014-12-01

Full Text Available Background. Mexico has the world’s fifth largest population of amphibians and the second country with the highest quantity of threatened amphibian species. About 10% of Mexican amphibians lack enough data to be assigned to a risk category by the IUCN, so in this paper we want to test a statistical tool that, in the absence of specific demographic data, can assess a species’ risk of extinction, population trend, and to better understand which variables increase their vulnerability. Recent studies have demonstrated that the risk of species decline depends on extrinsic and intrinsic traits, thus including both of them for assessing extinction might render more accurate assessment of threats.Methods. We harvested data from the Encyclopedia of Life (EOL and the published literature for Mexican amphibians, and used these data to assess the population trend of some of the Mexican species that have been assigned to the Data Deficient category of the IUCN using Random Forests, a Machine Learning method that gives a prediction of complex processes and identifies the most important variables that account for the predictions.Results. Our results show that most of the data deficient Mexican amphibians that we used have decreasing population trends. We found that Random Forests is a solid way to identify species with decreasing population trends when no demographic data is available. Moreover, we point to the most important variables that make species more vulnerable for extinction. This exercise is a very valuable first step in assigning conservation priorities for poorly known species.

A statistical assessment of population trends for data deficient Mexican amphibians.

Science.gov (United States)

Quintero, Esther; Thessen, Anne E; Arias-Caballero, Paulina; Ayala-Orozco, Bárbara

2014-01-01

Background. Mexico has the world's fifth largest population of amphibians and the second country with the highest quantity of threatened amphibian species. About 10% of Mexican amphibians lack enough data to be assigned to a risk category by the IUCN, so in this paper we want to test a statistical tool that, in the absence of specific demographic data, can assess a species' risk of extinction, population trend, and to better understand which variables increase their vulnerability. Recent studies have demonstrated that the risk of species decline depends on extrinsic and intrinsic traits, thus including both of them for assessing extinction might render more accurate assessment of threats. Methods. We harvested data from the Encyclopedia of Life (EOL) and the published literature for Mexican amphibians, and used these data to assess the population trend of some of the Mexican species that have been assigned to the Data Deficient category of the IUCN using Random Forests, a Machine Learning method that gives a prediction of complex processes and identifies the most important variables that account for the predictions. Results. Our results show that most of the data deficient Mexican amphibians that we used have decreasing population trends. We found that Random Forests is a solid way to identify species with decreasing population trends when no demographic data is available. Moreover, we point to the most important variables that make species more vulnerable for extinction. This exercise is a very valuable first step in assigning conservation priorities for poorly known species.

Skin microbiota in frogs from the Brazilian Atlantic Forest: Species, forest type, and potential against pathogens.

Science.gov (United States)

Assis, Ananda Brito de; Barreto, Cristine Chaves; Navas, Carlos Arturo

2017-01-01

The cutaneous microbiota of amphibians can be defined as a biological component of protection, since it can be composed of bacteria that produce antimicrobial compounds. Several factors influence skin microbial structure and it is possible that environmental variations are among one of these factors, perhaps through physical-chemical variations in the skin. This community, therefore, is likely modified in habitats in which some ecophysiological parameters are altered, as in fragmented forests. Our research goal was to compare the skin bacterial community of four anuran species of the Atlantic Forest of Brazil in landscapes from two different environments: continuous forest and fragmented forest. The guiding hypotheses were: 1) microbial communities of anuran skin vary among sympatric frog species of the Atlantic forest; 2) the degree to which forested areas are intact affects the cutaneous bacterial community of amphibians. If the external environment influences the skin microbiota, and if such influences affect microorganisms capable of inhibiting the colonization of pathogens, we expect consequences for the protection of host individuals. We compared bacterial communities based on richness and density of colony forming units; investigated the antimicrobial potential of isolated strains; and did the taxonomic identification of isolated morphotypes. We collected 188 individual frogs belonging to the species Proceratophrys boiei, Dendropsophus minutus, Aplastodiscus leucopygius and Phyllomedusa distincta, and isolated 221 bacterial morphotypes. Our results demonstrate variation in the skin microbiota of sympatric amphibians, but only one frog species exhibited differences in the bacterial communities between populations from fragmented and continuous forest. Therefore, the variation we observed is probably derived from both intrinsic aspects of the host amphibian species and extrinsic aspects of the environment occupied by the host. Finally, we detected

Endemic infection of the amphibian chytrid fungus in a frog community post-decline.

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Richard W R Retallick

2004-11-01

Full Text Available The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of numerous frog species worldwide. In Queensland, Australia, it has been proposed as the cause of the decline or apparent extinction of at least 14 high-elevation rainforest frog species. One of these, Taudactylus eungellensis, disappeared from rainforest streams in Eungella National Park in 1985-1986, but a few remnant populations were subsequently discovered. Here, we report the analysis of B. dendrobatidis infections in toe tips of T. eungellensis and sympatric species collected in a mark-recapture study between 1994 and 1998. This longitudinal study of the fungus in individually marked frogs sheds new light on the effect of this threatening infectious process in field, as distinct from laboratory, conditions. We found a seasonal peak of infection in the cooler months, with no evidence of interannual variation. The overall prevalence of infection was 18% in T. eungellensis and 28% in Litoria wilcoxii/jungguy, a sympatric frog that appeared not to decline in 1985-1986. No infection was found in any of the other sympatric species. Most importantly, we found no consistent evidence of lower survival in T. eungellensis that were infected at the time of first capture, compared with uninfected individuals. These results refute the hypothesis that remnant populations of T. eungellensis recovered after a B. dendrobatidis epidemic because the pathogen had disappeared. They show that populations of T. eungellensis now persist with stable, endemic infections of B. dendrobatidis.

Endemic infection of the amphibian chytrid fungus in a frog community post-decline.

Science.gov (United States)

Retallick, Richard W R; McCallum, Hamish; Speare, Rick

2004-11-01

The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of numerous frog species worldwide. In Queensland, Australia, it has been proposed as the cause of the decline or apparent extinction of at least 14 high-elevation rainforest frog species. One of these, Taudactylus eungellensis, disappeared from rainforest streams in Eungella National Park in 1985-1986, but a few remnant populations were subsequently discovered. Here, we report the analysis of B. dendrobatidis infections in toe tips of T. eungellensis and sympatric species collected in a mark-recapture study between 1994 and 1998. This longitudinal study of the fungus in individually marked frogs sheds new light on the effect of this threatening infectious process in field, as distinct from laboratory, conditions. We found a seasonal peak of infection in the cooler months, with no evidence of interannual variation. The overall prevalence of infection was 18% in T. eungellensis and 28% in Litoria wilcoxii/jungguy, a sympatric frog that appeared not to decline in 1985-1986. No infection was found in any of the other sympatric species. Most importantly, we found no consistent evidence of lower survival in T. eungellensis that were infected at the time of first capture, compared with uninfected individuals. These results refute the hypothesis that remnant populations of T. eungellensis recovered after a B. dendrobatidis epidemic because the pathogen had disappeared. They show that populations of T. eungellensis now persist with stable, endemic infections of B. dendrobatidis.

Drought, deluge and declines: the impact of precipitation extremes on amphibians in a changing climate

Science.gov (United States)

Walls, Susan C.; Barichivich, William J.; Brown, Mary E.

2013-01-01

The Class Amphibia is one of the most severely impacted taxa in an on-going global biodiversity crisis. Because amphibian reproduction is tightly associated with the presence of water, climatic changes that affect water availability pose a particularly menacing threat to both aquatic and terrestrial-breeding amphibians. We explore the impacts that one facet of climate change—that of extreme variation in precipitation—may have on amphibians. This variation is manifested principally as increases in the incidence and severity of both drought and major storm events. We stress the need to consider not only total precipitation amounts but also the pattern and timing of rainfall events. Such rainfall “pulses” are likely to become increasingly more influential on amphibians, especially in relation to seasonal reproduction. Changes in reproductive phenology can strongly influence the outcome of competitive and predatory interactions, thus potentially altering community dynamics in assemblages of co-existing species. We present a conceptual model to illustrate possible landscape and metapopulation consequences of alternative climate change scenarios for pond-breeding amphibians, using the Mole Salamander, Ambystoma talpoideum, as an example. Although amphibians have evolved a variety of life history strategies that enable them to cope with environmental uncertainty, it is unclear whether adaptations can keep pace with the escalating rate of climate change. Climate change, especially in combination with other stressors, is a daunting challenge for the persistence of amphibians and, thus, the conservation of global biodiversity.

Testing the impact of miniaturization on phylogeny: Paleozoic dissorophoid amphibians.

Science.gov (United States)

Fröbisch, Nadia B; Schoch, Rainer R

2009-06-01

Among the diverse clade of Paleozoic dissorophoid amphibians, the small, terrestrial amphibamids and the neotenic branchiosaurids have frequently been suggested as possible antecedents of either all or some of the modern amphibian clades. Classically, amphibamids and branchiosaurids have been considered to represent distinct, but closely related clades within dissorophoids, but despite their importance for the controversial lissamphibian origins, a comprehensive phylogenetic analysis of small dissorophoids has thus far not been attempted. On the basis of an integrated data set, the relationships of amphibamids and branchiosaurids were analyzed using parsimony and Bayesian approaches. Both groups represent miniaturized forms and it was tested whether similar developmental pathways, associated with miniaturization, lead to an artificial close relationship of branchiosaurids and amphibamids. Moreover, the fit of the resulting tree topologies to the distribution of fossil taxa in the stratigraphic rock record was assessed as an additional source of information. The results show that characters associated with a miniaturized morphology are not responsible for the close clustering of branchiosaurids and amphibamids. Instead, all analyses invariably demonstrate a monophyletic clade of branchiosaurids highly nested within derived amphibamids, indicating that branchiosaurids represent a group of secondarily neotenic amphibamid dissorophoids. This understanding of the phylogenetic relationships of small dissorophoid amphibians provides a new framework for the discussion of their evolutionary history and the evolution of characters shared by branchiosaurids and/or amphibamids with modern amphibian taxa.

Phylogenetically-informed priorities for amphibian conservation.

Science.gov (United States)

Isaac, Nick J B; Redding, David W; Meredith, Helen M; Safi, Kamran

2012-01-01

The amphibian decline and extinction crisis demands urgent action to prevent further large numbers of species extinctions. Lists of priority species for conservation, based on a combination of species' threat status and unique contribution to phylogenetic diversity, are one tool for the direction and catalyzation of conservation action. We describe the construction of a near-complete species-level phylogeny of 5713 amphibian species, which we use to create a list of evolutionarily distinct and globally endangered species (EDGE list) for the entire class Amphibia. We present sensitivity analyses to test the robustness of our priority list to uncertainty in species' phylogenetic position and threat status. We find that both sources of uncertainty have only minor impacts on our 'top 100' list of priority species, indicating the robustness of the approach. By contrast, our analyses suggest that a large number of Data Deficient species are likely to be high priorities for conservation action from the perspective of their contribution to the evolutionary history.

Phylogenetically-informed priorities for amphibian conservation.

Directory of Open Access Journals (Sweden)

Nick J B Isaac

Full Text Available The amphibian decline and extinction crisis demands urgent action to prevent further large numbers of species extinctions. Lists of priority species for conservation, based on a combination of species' threat status and unique contribution to phylogenetic diversity, are one tool for the direction and catalyzation of conservation action. We describe the construction of a near-complete species-level phylogeny of 5713 amphibian species, which we use to create a list of evolutionarily distinct and globally endangered species (EDGE list for the entire class Amphibia. We present sensitivity analyses to test the robustness of our priority list to uncertainty in species' phylogenetic position and threat status. We find that both sources of uncertainty have only minor impacts on our 'top 100' list of priority species, indicating the robustness of the approach. By contrast, our analyses suggest that a large number of Data Deficient species are likely to be high priorities for conservation action from the perspective of their contribution to the evolutionary history.

Two-stage recovery of amphibian assemblages following selective logging of tropical forests.

Science.gov (United States)

Adum, Gilbert Baase; Eichhorn, Markus Peter; Oduro, William; Ofori-Boateng, Caleb; Rödel, Mark-Oliver

2013-04-01

There is a lack of quantitative information on the effectiveness of selective-logging practices in ameliorating effects of logging on faunal communities. We conducted a large-scale replicated field study in 3 selectively logged moist semideciduous forests in West Africa at varying times after timber extraction to assess post logging effects on amphibian assemblages. Specifically, we assessed whether the diversity, abundance, and assemblage composition of amphibians changed over time for forest-dependent species and those tolerant of forest disturbance. In 2009, we sampled amphibians in 3 forests (total of 48 study plots, each 2 ha) in southwestern Ghana. In each forest, we established plots in undisturbed forest, recently logged forest, and forest logged 10 and 20 years previously. Logging intensity was constant across sites with 3 trees/ha removed. Recently logged forests supported substantially more species than unlogged forests. This was due to an influx of disturbance-tolerant species after logging. Simultaneously Simpson's index decreased, with increased in dominance of a few species. As time since logging increased richness of disturbance-tolerant species decreased until 10 years after logging when their composition was indistinguishable from unlogged forests. Simpson's index increased with time since logging and was indistinguishable from unlogged forest 20 years after logging. Forest specialists decreased after logging and recovered slowly. However, after 20 years amphibian assemblages had returned to a state indistinguishable from that of undisturbed forest in both abundance and composition. These results demonstrate that even with low-intensity logging (≤3 trees/ha) a minimum 20-year rotation of logging is required for effective conservation of amphibian assemblages in moist semideciduous forests. Furthermore, remnant patches of intact forests retained in the landscape and the presence of permanent brooks may aid in the effective recovery of amphibian

Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors

Science.gov (United States)

Knapp, Roland A.; Fellers, Gary M.; Kleeman, Patrick M.; Miller, David A. W.; Vrendenburg, Vance T.; Rosenblum, Erica Bree; Briggs, Cheryl J.

2016-01-01

Amphibians are one of the most threatened animal groups, with 32% of species at risk for extinction. Given this imperiled status, is the disappearance of a large fraction of the Earth’s amphibians inevitable, or are some declining species more resilient than is generally assumed? We address this question in a species that is emblematic of many declining amphibians, the endangered Sierra Nevada yellow-legged frog (Rana sierrae). Based on >7,000 frog surveys conducted across Yosemite National Park over a 20-y period, we show that, after decades of decline and despite ongoing exposure to multiple stressors, including introduced fish, the recently emerged disease chytridiomycosis, and pesticides, R. sierrae abundance increased sevenfold during the study and at a rate of 11% per year. These increases occurred in hundreds of populations throughout Yosemite, providing a rare example of amphibian recovery at an ecologically relevant spatial scale. Results from a laboratory experiment indicate that these increases may be in part because of reduced frog susceptibility to chytridiomycosis. The disappearance of nonnative fish from numerous water bodies after cessation of stocking also contributed to the recovery. The large-scale increases in R. sierrae abundance that we document suggest that, when habitats are relatively intact and stressors are reduced in their importance by active management or species’ adaptive responses, declines of some amphibians may be partially reversible, at least at a regional scale. Other studies conducted over similarly large temporal and spatial scales are critically needed to provide insight and generality about the reversibility of amphibian declines at a global scale.

Radioactive contamination of amphibian in the Chernobyl zone

International Nuclear Information System (INIS)

Bondar'kov, M.D.; Gashchak, S.P.; Goryanaya, Yu.A.

2002-01-01

In result of our investigations there was found out, that though there are great variations of accumulation indices of 90 Sr and 137 Cs, there are certain species differences between amphibians. Basing on general ideas, it can be caused by features of nutrition, behavior and ecology of the species. Terrestrial forms accumulate 137 Cs more than water one, and toads have more high indices of 90 Sr accumulation than frogs. It can been expected, that larvae stages of the terrestrial amphibians, due to water living, will have lower parameters of the radionuclide accumulation, than individuals came on dry land. They also must have and more low variation coefficient of TF values. However, it demands to be checked

Special Issue: Viruses Infecting Fish, Amphibians, and Reptiles

Directory of Open Access Journals (Sweden)

V. Gregory Chinchar

2011-09-01

Full Text Available Although viruses infecting and affecting humans are the focus of considerable research effort, viruses that target other animal species, including cold-blooded vertebrates, are receiving increased attention. In part this reflects the interests of comparative virologists, but increasingly it is based on the impact that many viruses have on ecologically and commercially important animals. Frogs and other amphibians are sentinels of environmental health and their disappearance following viral or fungal (chytrid infection is a cause for alarm. Likewise, because aquaculture and mariculture are providing an increasingly large percentage of the “seafood” consumed by humans, viral agents that adversely impact the harvest of cultured fish and amphibians are of equal concern. [...

Chytridiomycosis and seasonal mortality of tropical stream-associated frogs 15 years after introduction of Batrachochytrium dendrobatidis.

Science.gov (United States)

Phillott, Andrea D; Grogan, Laura F; Cashins, Scott D; McDonald, Keith R; Berger, Lee; Skerratt, Lee F

2013-10-01

Assessing the effects of diseases on wildlife populations can be difficult in the absence of observed mortalities, but it is crucial for threat assessment and conservation. We performed an intensive capture-mark-recapture study across seasons and years to investigate the effect of chytridiomycosis on demographics in 2 populations of the threatened common mist frog (Litoria rheocola) in the lowland wet tropics of Queensland, Australia. Infection prevalence was the best predictor for apparent survival probability in adult males and varied widely with season (0-65%). Infection prevalence was highest in winter months when monthly survival probabilities were low (approximately 70%). Populations at both sites exhibited very low annual survival probabilities (12-15%) but high recruitment (71-91%), which resulted in population growth rates that fluctuated seasonally. Our results suggest that even in the absence of observed mortalities and continued declines, and despite host-pathogen co-existence for multiple host generations over almost 2 decades, chytridiomycosis continues to have substantial seasonally fluctuating population-level effects on amphibian survival, which necessitates increased recruitment for population persistence. Similarly infected populations may thus be under continued threat from chytridiomycosis which may render them vulnerable to other threatening processes, particularly those affecting recruitment success. © 2013 Society for Conservation Biology.

Amphibians and reptiles of the state of Chihuahua, Mexico, with comparisons with adjoining states

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Julio A. Lemos-Espinal

2017-02-01

Full Text Available Chihuahua is Mexico’s largest state, and its physiographic complexity affects the distribution of its herpetofauna. We list amphibians and reptiles for the state of Chihuahua, with their conservation status. We also compare this list to those of six adjoining states in the United States and Mexico (New Mexico, Texas, Coahuila, Durango, Sinaloa, and Sonora. A total of 175 species of amphibians and reptiles is found in Chihuahua. Thirty-eight are amphibians, and 137 reptiles. Chihuahuan amphibians and reptiles represent just over 37% of such species from Chihuahua and neighboring states. Chihuahua shares the highest proportion of its herpetofauna with Sonora and Durango. Most of the herpetofauna of Chihuahua falls in IUCNs least concern category and is not listed by SEMARNAT. However, turtles in Chihuahua are a group of particular conservation concern.

Amphibians and reptiles of the state of Chihuahua, Mexico, with comparisons with adjoining states.

Science.gov (United States)

Lemos-Espinal, Julio A; Smith, Geoffrey R; Woolrich-Piña, Guillermo A; Cruz, Alexander

2017-01-01

Chihuahua is Mexico's largest state, and its physiographic complexity affects the distribution of its herpetofauna. We list amphibians and reptiles for the state of Chihuahua, with their conservation status. We also compare this list to those of six adjoining states in the United States and Mexico (New Mexico, Texas, Coahuila, Durango, Sinaloa, and Sonora). A total of 175 species of amphibians and reptiles is found in Chihuahua. Thirty-eight are amphibians, and 137 reptiles. Chihuahuan amphibians and reptiles represent just over 37% of such species from Chihuahua and neighboring states. Chihuahua shares the highest proportion of its herpetofauna with Sonora and Durango. Most of the herpetofauna of Chihuahua falls in IUCNs least concern category and is not listed by SEMARNAT. However, turtles in Chihuahua are a group of particular conservation concern.

Physical habitat and its alteration: A common ground for exposure of amphibians to environmental stressors

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Bishop, Christine A.; Cunnington, David C.; Fellers, Gary M.; Gibbs, James P.; Pauli, Bruce D.; Rothermel, Betsie B.; Linder, Greg L.; Krest, Sherry K.; Sparling, Donald W.

2003-01-01

Amphibians as a class of vertebrates have persisted for hundreds of millions of years (Stebbins and Cohen 1995), but they are currently threatened by a variety of stressors, many resulting from human-related alterations of the environment. Most species of amphibians live closely associated with moist environments throughout their life and have evolved specialized adaptations that conserve water and reduce desiccation (Stebbins and Cohen 1995; Henry 2000; Chapter 2A). Amphibians are ectotherms, so their body temperatures fluctuate with the local environment. Latitude, elevation, and habitat affect environmental temperature and have a strong influence on amphibian distributions. Despite these physiological and habitat constraints, the 4750 species of amphibians in the world today have exploited a wide variety of habitats that range from dry deserts to tropical rain forests and from sea level to elevations above 4000 m (McDairmid and Mitchell 2000).The direct loss of suitable habitat has had a profound effect on amphibian populations (Johnson 1992), as it has on nearly all species of wildlife. In the U.S., 53% of wetlands have been lost to human development in the last 200 years (Dahl 1990). Similar loss of wetlands has occurred throughout much of the world, especially in developing countries (Miller 1993). In many regions, deforestation has reduced or eliminated suitable terrestrial habitats, and this may prove to be the largest global threat to amphibian populations (Johnson 1992). Eight thousand years ago, forests covered approximately 40% of the world’s land (6 billion hectares), but by 1997, the world’s forests had been reduced to 3.5 billion hectares, a 42% loss worldwide (CIDA 2001). The effect of habitat loss is generally both obvious and predictable; with increasing restriction of suitable habitat, amphibian populations will probably not survive. The anthropogenic effects on the quality of the habitat that remains are often less obvious.

Count data, detection probabilities, and the demography, dynamics, distribution, and decline of amphibians.

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Schmidt, Benedikt R

2003-08-01

The evidence for amphibian population declines is based on count data that were not adjusted for detection probabilities. Such data are not reliable even when collected using standard methods. The formula C = Np (where C is a count, N the true parameter value, and p is a detection probability) relates count data to demography, population size, or distributions. With unadjusted count data, one assumes a linear relationship between C and N and that p is constant. These assumptions are unlikely to be met in studies of amphibian populations. Amphibian population data should be based on methods that account for detection probabilities.

Acute toxicity tests and meta-analysis identify gaps in tropical ecotoxicology for amphibians.

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Ghose, Sonia L; Donnelly, Maureen A; Kerby, Jacob; Whitfield, Steven M

2014-09-01

Amphibian populations are declining worldwide, particularly in tropical regions where amphibian diversity is highest. Pollutants, including agricultural pesticides, have been identified as a potential contributor to decline, yet toxicological studies of tropical amphibians are very rare. The present study assesses toxic effects on amphibians of 10 commonly used commercial pesticides in tropical agriculture using 2 approaches. First, the authors conducted 8-d toxicity assays with formulations of each pesticide using individually reared red-eyed tree frog (Agalychnis callidryas) tadpoles. Second, they conducted a review of available data for the lethal concentration to kill 50% of test animals from the US Environmental Protection Agency's ECOTOX database to allow comparison with their findings. Lethal concentration estimates from the assays ranged over several orders of magnitude. The nematicides terbufos and ethoprophos and the fungicide chlorothalonil were very highly toxic, with evident effects within an order of magnitude of environmental concentrations. Acute toxicity assays and meta-analysis show that nematicides and fungicides are generally more toxic than herbicides yet receive far less research attention than less toxic herbicides. Given that the tropics have a high diversity of amphibians, the findings emphasize the need for research into the effects of commonly used pesticides in tropical countries and should help guide future ecotoxicological research in tropical regions. © 2014 SETAC.

Independent evolution of the sexes promotes amphibian diversification

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De Lisle, Stephen P.; Rowe, Locke

2015-01-01

Classic ecological theory predicts that the evolution of sexual dimorphism constrains diversification by limiting morphospace available for speciation. Alternatively, sexual selection may lead to the evolution of reproductive isolation and increased diversification. We test contrasting predictions of these hypotheses by examining the relationship between sexual dimorphism and diversification in amphibians. Our analysis shows that the evolution of sexual size dimorphism (SSD) is associated with increased diversification and speciation, contrary to the ecological theory. Further, this result is unlikely to be explained by traditional sexual selection models because variation in amphibian SSD is unlikely to be driven entirely by sexual selection. We suggest that relaxing a central assumption of classic ecological models—that the sexes share a common adaptive landscape—leads to the alternative hypothesis that independent evolution of the sexes may promote diversification. Once the constraints of sexual conflict are relaxed, the sexes can explore morphospace that would otherwise be inaccessible. Consistent with this novel hypothesis, the evolution of SSD in amphibians is associated with reduced current extinction threat status, and an historical reduction in extinction rate. Our work reconciles conflicting predictions from ecological and evolutionary theory and illustrates that the ability of the sexes to evolve independently is associated with a spectacular vertebrate radiation. PMID:25694616

Engineering a future for amphibians under climate change

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Shoo, L.P.; Olson, D.H.; Mcmenamin, S.K.; Murray, K.A.; Van Sluys, M.; Donnelly, M.A.; Stratford, D.; Terhivuo, J.; Merino-Viteri, A.; Herbert, S.M.; Bishop, P.J.; Corn, P.S.; Dovey, L.; Griffiths, R.A.; Lowe, K.; Mahony, M.; McCallum, H.; Shuker, J.D.; Simpkins, C.; Skerratt, L.F.; Williams, S.E.; Hero, J.-M.

2011-01-01

1. Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. 2. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were grouped under three thematic areas of intervention: (i) installation of microclimate and microhabitat refuges; (ii) enhancement and restoration of breeding sites; and (iii) manipulation of hydroperiod or water levels at breeding sites. 3. Synthesis and applications. There are currently few meaningful management actions that will tangibly impact the pervasive threat of climate change on amphibians. A host of potentially useful but poorly tested actions could be incorporated into local or regional management plans, programmes and activities for amphibians. Examples include: installation of irrigation sprayers to manipulate water potentials at breeding sites; retention or supplementation of natural and artificial shelters (e.g. logs, cover boards) to reduce desiccation and thermal stress; manipulation of canopy cover over ponds to reduce water temperature; and, creation of hydrologoically diverse wetland habitats capable of supporting larval development under variable rainfall regimes. We encourage researchers and managers to design, test and scale up new initiatives to respond to this emerging crisis.

DNA barcoding applied to ex situ tropical amphibian conservation programme reveals cryptic diversity in captive populations.

Science.gov (United States)

Crawford, Andrew J; Cruz, Catalina; Griffith, Edgardo; Ross, Heidi; Ibáñez, Roberto; Lips, Karen R; Driskell, Amy C; Bermingham, Eldredge; Crump, Paul

2013-11-01

Amphibians constitute a diverse yet still incompletely characterized clade of vertebrates, in which new species are still being discovered and described at a high rate. Amphibians are also increasingly endangered, due in part to disease-driven threats of extinctions. As an emergency response, conservationists have begun ex situ assurance colonies for priority species. The abundance of cryptic amphibian diversity, however, may cause problems for ex situ conservation. In this study we used a DNA barcoding approach to survey mitochondrial DNA (mtDNA) variation in captive populations of 10 species of Neotropical amphibians maintained in an ex situ assurance programme at El Valle Amphibian Conservation Center (EVACC) in the Republic of Panama. We combined these mtDNA sequences with genetic data from presumably conspecific wild populations sampled from across Panama, and applied genetic distance-based and character-based analyses to identify cryptic lineages. We found that three of ten species harboured substantial cryptic genetic diversity within EVACC, and an additional three species harboured cryptic diversity among wild populations, but not in captivity. Ex situ conservation efforts focused on amphibians are therefore vulnerable to an incomplete taxonomy leading to misidentification among cryptic species. DNA barcoding may therefore provide a simple, standardized protocol to identify cryptic diversity readily applicable to any amphibian community. © 2012 John Wiley & Sons Ltd.

Inventory of Amphibians and Reptiles at Mojave National Preserve: Final Report

Science.gov (United States)

Persons, Trevor B.; Nowak, Erika M.

2007-01-01

As part of the National Park Service Inventory and Monitoring Program in the Mojave Network, we conducted an inventory of amphibians and reptiles at Mojave National Preserve in 2004-2005. Objectives for this inventory were to use fieldwork, museum collections, and literature review to document the occurrence of reptile and amphibian species occurring at MOJA. Our goals were to document at least 90% of the species present, provide one voucher specimen for each species identified, provide GIS-referenced distribution information for sensitive species, and provide all deliverables, including NPSpecies entries, as outlined in the Mojave Network Biological Inventory Study Plan. Methods included daytime and nighttime visual encounter surveys and nighttime road driving. Survey effort was concentrated in predetermined priority sampling areas, as well as in areas with a high potential for detecting undocumented species. We recorded 31 species during our surveys. During literature review and museum specimen database searches, we found records for seven additional species from MOJA, elevating the documented species list to 38 (two amphibians and 36 reptiles). Based on our surveys, as well as literature and museum specimen review, we estimate an overall inventory completeness of 95% for Mojave National Preserve herpetofauna; 67% for amphibians and 97% for reptiles.

Can we enhance amphibians? habitat restoration in the post-mining areas?

OpenAIRE

Klimaszewski, Krzysztof; Pacholik, Ewa; Snopek, Adam

2015-01-01

The study was aimed to evaluate the selected improvements of nature restoration in a depleted gravel pit. The study site consisted of four water reservoirs of different shapes and sizes, flooded after the gravel extraction ended. Ecological succession monitoring, conducted by the Warsaw University of Life Sciences students associated in the Student Scientific Association of Animal Sciences Faculty since the completion of mining, have focused on amphibians. A twofold approach upheld amphibian ...

Habitat split and the global decline of amphibians.

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Becker, Carlos Guilherme; Fonseca, Carlos Roberto; Haddad, Célio Fernando Baptista; Batista, Rômulo Fernandes; Prado, Paulo Inácio

2007-12-14

The worldwide decline in amphibians has been attributed to several causes, especially habitat loss and disease. We identified a further factor, namely "habitat split"-defined as human-induced disconnection between habitats used by different life history stages of a species-which forces forest-associated amphibians with aquatic larvae to make risky breeding migrations between suitable aquatic and terrestrial habitats. In the Brazilian Atlantic Forest, we found that habitat split negatively affects the richness of species with aquatic larvae but not the richness of species with terrestrial development (the latter can complete their life cycle inside forest remnants). This mechanism helps to explain why species with aquatic larvae have the highest incidence of population decline. These findings reinforce the need for the conservation and restoration of riparian vegetation.

Using monitoring data to map amphibian breeding hotspots and describe wetland vulnerability in Yellowstone and Grand Teton National Parks

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Ray, Andrew M.; Legg, Kristin; Sepulveda, Adam; Hossack, Blake R.; Patla, Debra

2015-01-01

Amphibians have been selected as a “vital sign” by several National Park Service (NPS) Inventory and Monitoring (I&M) networks. An eight-year amphibian monitoring data set provided opportunities to examine spatial and temporal patterns in amphibian breeding richness and wetland desiccation across Yellowstone and Grand Teton National Parks. Amphibian breeding richness was variable across both parks and only four of 31 permanent monitoring catchments contained all four widely distributed species. Annual breeding richness was also variable through time and fluctuated by as much as 75% in some years and catchments. Wetland desiccation was also documented across the region, but alone did not explain variations in amphibian richness. High annual variability across the region emphasizes the need for multiple years of monitoring to accurately describe amphibian richness and wetland desiccation dynamics.

Estrogens can disrupt amphibian mating behavior.

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Frauke Hoffmann

Full Text Available The main component of classical contraceptives, 17α-ethinylestradiol (EE2, has high estrogenic activity even at environmentally relevant concentrations. Although estrogenic endocrine disrupting compounds are assumed to contribute to the worldwide decline of amphibian populations by adverse effects on sexual differentiation, evidence for EE2 affecting amphibian mating behaviour is lacking. In this study, we demonstrate that EE2 exposure at five different concentrations (0.296 ng/L, 2.96 ng/L, 29.64 ng/L, 2.96 µg/L and 296.4 µg/L can disrupt the mating behavior of adult male Xenopus laevis. EE2 exposure at all concentrations lowered male sexual arousal, indicated by decreased proportions of advertisement calls and increased proportions of the call type rasping, which characterizes a sexually unaroused state of a male. Additionally, EE2 at all tested concentrations affected temporal and spectral parameters of the advertisement calls, respectively. The classical and highly sensitive biomarker vitellogenin, on the other hand, was only induced at concentrations equal or higher than 2.96 µg/L. If kept under control conditions after a 96 h EE2 exposure (2.96 µg/L, alterations of male advertisement calls vanish gradually within 6 weeks and result in a lower sexual attractiveness of EE2 exposed males toward females as demonstrated by female choice experiments. These findings indicate that exposure to environmentally relevant EE2 concentrations can directly disrupt male mate calling behavior of X. laevis and can indirectly affect the mating behavior of females. The results suggest the possibility that EE2 exposure could reduce the reproductive success of EE2 exposed animals and these effects might contribute to the global problem of amphibian decline.

Amphibians and reptiles of C. E. Miller Ranch and the Sierra Vieja, Chihuahuan Desert, Texas, USA

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Drew R. Davis

2018-02-01

Full Text Available We report the occurrence of 50 species of amphibians and reptiles recently collected on C. E. Miller Ranch and the Sierra Vieja in the Chihuahuan Desert of Texas, USA and describe their perceived distribution and abundance across various habitat associations of the region. Our recent surveys follow intense, historic sampling of amphibians and reptiles from this region in 1948. Of the 50 species detected in recent surveys, six were not collected in 1948 and an additional three species documented in 1948 have yet to be detected in a 14-year period of recent surveys. Combining data from both historic and recent surveys, a total of 53 species of amphibians and reptiles are known from the ranch (11 amphibians, 42 reptiles. Land stewardship and conservation practices have likely contributed to the persistence of the majority of these species through time. Additionally, we discuss the status of amphibians and reptiles not collected during recent surveys and comment on potential species that have not yet been detected.

Amphibians and reptiles of C. E. Miller Ranch and the Sierra Vieja, Chihuahuan Desert, Texas, USA.

Science.gov (United States)

Davis, Drew R; LaDuc, Travis J

2018-01-01

We report the occurrence of 50 species of amphibians and reptiles recently collected on C. E. Miller Ranch and the Sierra Vieja in the Chihuahuan Desert of Texas, USA and describe their perceived distribution and abundance across various habitat associations of the region. Our recent surveys follow intense, historic sampling of amphibians and reptiles from this region in 1948. Of the 50 species detected in recent surveys, six were not collected in 1948 and an additional three species documented in 1948 have yet to be detected in a 14-year period of recent surveys. Combining data from both historic and recent surveys, a total of 53 species of amphibians and reptiles are known from the ranch (11 amphibians, 42 reptiles). Land stewardship and conservation practices have likely contributed to the persistence of the majority of these species through time. Additionally, we discuss the status of amphibians and reptiles not collected during recent surveys and comment on potential species that have not yet been detected.

Terrestrial pesticide exposure of amphibians: an underestimated cause of global decline?

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Brühl, Carsten A; Schmidt, Thomas; Pieper, Silvia; Alscher, Annika

2013-01-01

Amphibians, a class of animals in global decline, are present in agricultural landscapes characterized by agrochemical inputs. Effects of pesticides on terrestrial life stages of amphibians such as juvenile and adult frogs, toads and newts are little understood and a specific risk assessment for pesticide exposure, mandatory for other vertebrate groups, is currently not conducted. We studied the effects of seven pesticide products on juvenile European common frogs (Rana temporaria) in an agricultural overspray scenario. Mortality ranged from 100% after one hour to 40% after seven days at the recommended label rate of currently registered products. The demonstrated toxicity is alarming and a large-scale negative effect of terrestrial pesticide exposure on amphibian populations seems likely. Terrestrial pesticide exposure might be underestimated as a driver of their decline calling for more attention in conservation efforts and the risk assessment procedures in place do not protect this vanishing animal group.

Geomorphology Drives Amphibian Beta Diversity in Atlantic Forest Lowlands of Southeastern Brazil

OpenAIRE

Luiz, Amom Mendes; Le?o-Pires, Thiago Augusto; Sawaya, Ricardo J.

2016-01-01

Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorph...

Terrestrial exposure and effects of Headline AMP(®) Fungicide on amphibians.

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Cusaac, J Patrick W; Mimbs, William H; Belden, Jason B; Smith, Loren M; McMurry, Scott T

2015-08-01

Recent studies have demonstrated that a pyraclostrobin-containing fungicide (Headline(®) Fungicide--Headline(®) Fungicide and Headline AMP(®) Fungicide are registered trademarks of BASF) is toxic to amphibians at environmentally relevant concentrations. However, these studies were performed in a laboratory setting of a worst-case direct exposure in clean media. Interception of spray by the crop canopy and ground cover used by animals for security cover will influence exposure. Thus, risk to amphibians is unclear in an environmentally realistic field environment. We tested exposure and toxicity of Headline AMP(®) Fungicide to amphibians in multiple agricultural habitat scenarios (e.g., within treated crop vs. grassy areas adjacent to crop) and at two rates during routine aerial application. Specifically, we placed Woodhouse's toads (Bufo woodhousii) and Blanchard's cricket frogs (Acris blanchardi) in enclosures located within treated and untreated corn (VT stage, approximate height = 3 m), and in the potential drift area (adjacent to treated corn) during aerial application of Headline AMP Fungicide at either 731 or 1052 ml/ha (70 and 100 % the maximum application rate in corn, respectively). Mean concentrations of pyraclostrobin measured at ground level were ≤19 % of nominal application rate in all areas. Overall, mean mortality of recovered individuals of both species was ≤15 %, and mortality within Headline AMP Fungicide-treated corn (where risk was anticipated to be highest) was <10 %. It is important to understand that application timing, interception by the crop canopy (which varies both within and between crop systems), and timing of amphibian presence in the crop field influences risk of exposure and effects; however, our results demonstrate that amphibians inhabiting VT stage corn during routine aerial application of Headline AMP Fungicide are at low risk for acute mortality, matching existing laboratory results from acute toxicity studies of

Phylogenic aspects of the amphibian dual olfactory system.

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Taniguchi, Kazumi; Saito, Shouichiro; Oikawa, Toshihiro; Taniguchi, Kazuyuki

2008-01-01

The phylogenic significance of the subdivision of dual olfactory system is reviewed mainly on the basis of our findings by electron microscopy and lectin histochemistry in the three amphibian species. The dual olfactory system is present in common in these species and consists of the projection from the olfactory epithelium (OE) to the main olfactory bulb (MOB) and that from the vomeronasal epithelium (VNE) to the accessory olfactory bulb (AOB). The phylogenic significance of subdivisions in the dual olfactory system in the amphibian must differently be interpreted. The subdivision of the MOB into its dorsal region (D-MOB) and ventral region (V-MOB) in Xenopus laevis must be attributed to the primitive features in their olfactory receptors. The middle cavity epithelium lining the middle cavity of this frog possesses both ciliated sensory cells and microvillous sensory cells, reminding the OE in fish. The subdivision of the AOB into the rostral (R-AOB) and caudal part (C-AOB) in Bufo japonicus formosus must be regarded as an advanced characteristic. The lack of subdivisions in both MOB and AOB in Cynops pyrrhogaster may reflect their phylogenic primitiveness. Since our lectin histochemistry to detect glycoconjugates expressed in the olfactory pathway reveals the subdivisions in the dual olfactory system in the amphibian, the glycoconjugates may deeply participate in the organization and function of olfactory pathways in phylogeny.

Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

Science.gov (United States)

Kim, Eunsoo; Lin, Yuan; Kerney, Ryan; Blumenberg, Lili; Bishop, Cory

2014-01-01

Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

Directory of Open Access Journals (Sweden)

Eunsoo Kim

Full Text Available Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille, which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

Initial diversification of living amphibians predated the breakup of Pangaea.

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San Mauro, Diego; Vences, Miguel; Alcobendas, Marina; Zardoya, Rafael; Meyer, Axel

2005-05-01

The origin and divergence of the three living orders of amphibians (Anura, Caudata, Gymnophiona) and their main lineages are one of the most hotly debated topics in vertebrate evolution. Here, we present a robust molecular phylogeny based on the nuclear RAG1 gene as well as results from a variety of alternative independent molecular clock calibrations. Our analyses suggest that the origin and early divergence of the three living amphibian orders dates back to the Palaeozoic or early Mesozoic, before the breakup of Pangaea, and soon after the divergence from lobe-finned fishes. The resulting new biogeographic scenario, age estimate, and the inferred rapid divergence of the three lissamphibian orders may account for the lack of fossils that represent plausible ancestors or immediate sister taxa of all three orders and the heretofore paradoxical distribution of some amphibian fossil taxa. Furthermore, the ancient and rapid radiation of the three lissamphibian orders likely explains why branch lengths connecting their early nodes are particularly short, thus rendering phylogenetic inference of implicated relationships especially difficult.

Managing Amphibian Disease with Skin Microbiota.

Science.gov (United States)

Woodhams, Douglas C; Bletz, Molly; Kueneman, Jordan; McKenzie, Valerie

2016-03-01

The contribution of emerging amphibian diseases to the sixth mass extinction is driving innovative wildlife management strategies, including the use of probiotics. Bioaugmentation of the skin mucosome, a dynamic environment including host and microbial components, may not provide a generalized solution. Multi-omics technologies and ecological context underlie effective implementation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Amphibian and reptile records from around the Betsiboka Delta area in North-Western Madagascar

NARCIS (Netherlands)

Rakotoarison, Andolalao; Erens, Jesse; Ratsoavina, Fanomezana M.; Vences, Miguel

2015-01-01

This study summarises amphibian and reptile records from ad hoc surveys in a series of localities in the North-West of Madagascar, largely centred on the delta of the Betsiboka River. Eleven amphibian and approximately 32 reptile species were found, with taxonomic uncertainties remaining for some

Analysis of three amphibian populations with quarter-century long time-series.

OpenAIRE

Meyer, A H; Schimidt, B R; Grossenbacher, K

1998-01-01

Amphibians are in decline in many parts of the world. Long tme-series of amphibian populations are necessary to distinguish declines from the often strong fluctuations observed in natural populations. Time-series may also help to understand the causes of these declines. We analysed 23-28-year long time-series of the frog Rana temporaria. Only one of the three studied populations showed a negative trend which was probably caused by the introduction of fish. Two populations appeared to be densi...

The pituitary-skin connection in amphibians. Reciprocal regulation of melanotrope cells and dermal melanocytes.

Science.gov (United States)

Vaudry, H; Chartrel, N; Desrues, L; Galas, L; Kikuyama, S; Mor, A; Nicolas, P; Tonon, M C

1999-10-20

In amphibians, alpha-MSH secreted by the pars intermedia of the pituitary plays a pivotal role in the process of skin color adaptation. Reciprocally, the skin of amphibians contains a number of regulatory peptides, some of which have been found to regulate the activity of pituitary melanotrope cells. In particular, the skin of certain species of amphibians harbours considerable amounts of thyrotropin-releasing hormone, a highly potent stimulator of alpha-MSH release. Recently, we have isolated and sequenced from the skin of the frog Phyllomedusa bicolor--a novel peptide named skin peptide tyrosine tyrosine (SPYY), which exhibits 94% similarity with PYY from the frog Rana ridibunda. For concentrations ranging from 5 x 10(-10) to 10(-7) M, SPYY induces a dose-related inhibition of alpha-MSH secretion. At a dose of 10(-7) M, SPYY totally abolished alpha-MSH release. These data strongly suggest the existence of a regulatory loop between the pars intermedia of the pituitary and the skin in amphibians.

South African red data book - Reptiles and Amphibians

CSIR Research Space (South Africa)

Mclachlan, GR

1978-02-01

Full Text Available Data sheets are provided for 46 threatened South African reptiles and amphibians, two being endangered (leatherback turtle, geometric tortoise) ten vulnerable (loggerhead turtle, Nile crocodile, veld monitor, water monitor, giant girdled lizard...

Can a Single Amphibian Species Be a Good Biodiversity Indicator?

Directory of Open Access Journals (Sweden)

David Sewell

2009-11-01

Full Text Available Although amphibians have been widely promoted as indicators of biodiversity and environmental change, rigorous tests are lacking. Here key indicator criteria are distilled from published papers, and a species that has been promoted as a bioindicator, the great crested newt, is tested against them. Although a link was established between the presence of great crested newts and aquatic plant diversity, this was not repeated with the diversity of macroinvertebrates. Equally, amphibians do not meet many of the published criteria of bioindicators. Our research suggests that a suite of indicators, rather than a single species, will usually be required.

Amphibians in the Environmental Park Chico Mendes, Rio Branco – Acre, Brazil

Directory of Open Access Journals (Sweden)

Nathocley Mendes Venâncio

2016-02-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2016v29n1p85 Acre’s amphibian fauna, although poorly known, is regarded as one of the most diversified. This study aimed to inventory the amphibian fauna in the Environmental Park Chico Mendes, a 57 ha forest fragment, located 7 km far from downtown Rio Branco. The study was conducted between August 2008 and July 2010, by using a visual and auditory search methodology. All tracks and temporary forest pools in the park were inventoried, where the individuals visualized or those using vocalization were registered. A total of 51 taxa were found, distributed into the orders: Anura, with 50 species, and Caudata, with 1 species. Amphibians in the park showed seasonality in reproduction, where the rainiest months were those with the highest number of species in reproductive activity.

Hurricane storm surge and amphibian communities in coastal wetlands of northwestern Florida

Science.gov (United States)

Gunzburger, M.S.; Hughes, W.B.; Barichivich, W.J.; Staiger, J.S.

2010-01-01

Isolated wetlands in the Southeastern United States are dynamic habitats subject to fluctuating environmental conditions. Wetlands located near marine environments are subject to alterations in water chemistry due to storm surge during hurricanes. The objective of our study was to evaluate the effect of storm surge overwash on wetland amphibian communities. Thirty-two wetlands in northwestern Florida were sampled over a 45-month period to assess amphibian species richness and water chemistry. During this study, seven wetlands were overwashed by storm surge from Hurricane Dennis which made landfall 10 July 2005 in the Florida panhandle. This event allowed us to evaluate the effect of storm surge overwash on water chemistry and amphibian communities of the wetlands. Specific conductance across all wetlands was low pre-storm (marine habitats are resistant to the effects of storm surge overwash. ?? 2010 Springer Science+Business Media B.V.

Photo-identification in amphibian studies: a test of I3S Pattern

Directory of Open Access Journals (Sweden)

Marco Sannolo

2016-06-01

Full Text Available Photo-identification is used for individual recognition of several animal species. It gives the possibility to take photos of large species from a distance or to avoid invasive marking techniques in small animals. For amphibians, the use of non-invasive marking methods is even more relevant in the light of their global decline. Here we use the photo-identification data from a population of Triturus carnifex to validate the photo-identification software I3S Pattern. This recently developed utility has never been applied to amphibians. The software proved to be efficient and accurate for individual recognition for this species. Contrarily to the previous releases of the I3S family, I3S Pattern is particularly suitable for amphibians characterized by a complex individual pattern of large blotches or irregular spots, which are not readily identified by eye.

Death in the clouds: ranavirus associated mortality in assemblage of cloud forest amphibians in Nicaragua

NARCIS (Netherlands)

Stark, T.; Laurijssens, C.; Weterings, M.J.A.; Spitzen-van der Sluis, A.; Martel, A.; Pasmans, F.

2014-01-01

Amphibian diseases are acknowledged as significant contributors to the decline and extinction of amphibian species. The main culprits currently considered are chytridiomycosis and Ranavirus. In Central America, highly endemic and geographical restricted terrestrial species may be at risk from these

Mine spoil prairies expand critical habitat for endangered and threatened amphibian and reptile species

Science.gov (United States)

Lannoo, Michael J.; Kinney, Vanessa C.; Heemeyer, Jennifer L.; Engbrecht, Nathan J.; Gallant, Alisa L.; Klaver, Robert W.

2009-01-01

Coal extraction has been occurring in the Midwestern United States for over a century. Despite the pre-mining history of the landscape as woodlands, spent surface coalfields are often reclaimed to grasslands. We assessed amphibian and reptile species on a large tract of coal spoil prairie and found 13 species of amphibians (nine frog and four salamander species) and 19 species of reptiles (one lizard, five turtle, and 13 snake species). Two state-endangered and three state species of special concern were documented. The amphibian diversity at our study site was comparable to the diversity found at a large restored prairie situated 175 km north, within the historic prairie peninsula.

Amphibians from Liberia and the Gold Coast

NARCIS (Netherlands)

Parker, H.W.

1936-01-01

Thanks to the courtesy of Drs. Boschma and Brongersma the author has been privileged to examine a large series of West African amphibians from the collections of the Royal Museum of Natural History in Leiden. Of the comparatively easily accessible parts of Africa, Liberia is probably the least

Detecting the effects of environmentally relevant concentrations of thyroid hormone disrupting compounds on amphibian development

NARCIS (Netherlands)

Gutleb, A.C.

2006-01-01

Persistent organic pollutants such as PCBs have been hypothesized to contribute to the observed global decline of amphibian populations. Thyroid hormone (TH) disruption is one of the possible mechanisms for effects of xenobiotics on amphibian development. In addition to the important functions

What's Slithering around on Your School Grounds? Transforming Student Awareness of Reptile & Amphibian Diversity

Science.gov (United States)

Tomasek, Terry M.; Matthews, Catherine E.; Hall, Jeff

2005-01-01

The protocols used in a research project on amphibian and reptile diversity at Cool Springs Environmental Education Center near New Bern, North Carolina is described. An increasing or stable number of amphibians and reptiles would indicate that the forest has a balance of invertebrates, leaf litter, moisture, pH, debris, burrows and habitat…

Prevalence and pathogen load estimates for the fungus Batrachochytrium dendrobatidis are impacted by ITS DNA copy number variation

DEFF Research Database (Denmark)

Rebollar, Eria A.; Woodhams, Douglas C.; LaBumbard, Brandon

2017-01-01

The ribosomal gene complex is a multi-copy region that is widely used for phylogenetic analyses of organisms from all 3 domains of life. In fungi, the copy number of the internal transcribed spacer (ITS) is used to detect abundance of pathogens causing diseases such as chytridiomycosis in amphibi...

From tails to toes: developing nonlethal tissue indicators of mercury exposure in five amphibian species.

Science.gov (United States)

Pfleeger, Adam Z; Eagles-Smith, Collin A; Kowalski, Brandon M; Herring, Garth; Willacker, James J; Jackson, Allyson K; Pierce, John R

2016-04-01

Exposure to environmental contaminants has been implicated as a factor in global amphibian decline. Mercury (Hg) is a particularly widespread contaminant that biomagnifies in amphibians and can cause a suite of deleterious effects. However, monitoring contaminant exposure in amphibian tissues may conflict with conservation goals if lethal take is required. Thus, there is a need to develop non-lethal tissue sampling techniques to quantify contaminant exposure in amphibians. Some minimally invasive sampling techniques, such as toe-clipping, are common in population-genetic research, but it is unclear if these methods can adequately characterize contaminant exposure. We examined the relationships between mercury (Hg) concentrations in non-lethally sampled tissues and paired whole-bodies in five amphibian species. Specifically, we examined the utility of three different tail-clip sections from four salamander species and toe-clips from one anuran species. Both tail and toe-clips accurately predicted whole-body THg concentrations, but the relationships differed among species and the specific tail-clip section or toe that was used. Tail-clips comprised of the distal 0-2 cm segment performed the best across all salamander species, explaining between 82 and 92% of the variation in paired whole-body THg concentrations. Toe-clips were less effective predictors of frog THg concentrations, but THg concentrations in outer rear toes accounted for up to 79% of the variability in frog whole-body THg concentrations. These findings suggest non-lethal sampling of tails and toes has potential applications for monitoring contaminant exposure and risk in amphibians, but care must be taken to ensure consistent collection and interpretation of samples.

Spatial and temporal variation in radiation exposure of amphibians - Implications for environmental risk assessment

Energy Technology Data Exchange (ETDEWEB)

Stark, K. [Stockholm University (Sweden)

2014-07-01

Although amphibians are threatened world-wide, many amphibian species are protected in national legislation. Thus, amphibians need special attention in many environmental risk assessments for releases of contaminants such as radionuclides. In fact, amphibians' ecology and physiology (including, for example, a complex life-cycle with both aquatic and terrestrial life stages, and a thin skin) makes them sensitive to radiation exposure. In current dose models for wildlife, homogenous distribution of radionuclides in soil is assumed. However, soils are heterogeneous environments and radionuclide contamination can be very unevenly distributed. As a consequence, bioaccumulation of radionuclides in biota may vary on a local scale. Specifically, organisms' spatial location and movement within habitats may affect both their external and internal exposure pattern to radionuclides. Therefore, measuring the spatial location of individual amphibians within ecosystems and understanding why they use these different locations is essential for predicting potential effects of released radionuclides on these populations. The aim of this study was to investigate amphibians' spatial distribution in a {sup 137}Cs contaminated wetland area and their body content of {sup 137}Cs at the beginning and end of the summer period. The study site was a wetland nature reserve called Bladmyra near Gaevle in the central-eastern part of Sweden. This area received fallout of {sup 137}Cs after the Chernobyl accident in 1986. This study measured the spatial distributions of two amphibian species (Rana arvalis and Bufo bufo) with Passive Integrated Transponder (PIT) tags in a mark-and-recapture study during 2012-2014. In addition, {sup 137}Cs body content in the two species was measured by whole body counting in spring and autumn of 2013. The results showed differences between years in how marked animals used the study area: More individuals stayed in a small area during 2012 than in 2013

Salmonella diversity associated with wild reptiles and amphibians in Spain.

Science.gov (United States)

Briones, Víctor; Téllez, Sonia; Goyache, Joaquín; Ballesteros, Cristina; del Pilar Lanzarot, María; Domínguez, Lucas; Fernández-Garayzábal, José F

2004-08-01

During the spring and summer of 2001, faeces from 166 wild reptiles (94 individuals) and amphibians (72 individuals) from 21 different species found in central Spain were examined for the presence of Salmonella. Thirty-nine reptiles (41.5%) yielded 48 Salmonella isolates, whereas all the amphibians examined were negative. Subspecies Salmonella enterica enterica (I) accounted for up to 50% of isolates. Fourteen isolates (29.2%) belonged to subspecies diarizonae (IIIb), six isolates (12.5%) to subspecies salamae (II), and four isolates (8.3%) to subspecies arizonae (IIIa). Twenty-seven different serotypes were identified. Serotypes Anatum (12.5%), Herzliya (8.3%), Abony, 18:l,v:z, 9,12:z29:1,5 and 38:z10:z53 (6.2%/each) were the most frequently isolated. A high percentage (39.6%) of isolates belonged to serotypes previously associated with environmental sources. Also, 37.5% of isolates belonged to serotypes which had been related to human cases of salmonellosis. From these data, it is concluded that wild reptiles, but apparently not amphibians, may represent an important reservoir of Salmonella in nature and have potential implications for public health.

19 CFR 12.26 - Importations of wild animals, fish, amphibians, reptiles, mollusks, and crustaceans; prohibited...

Science.gov (United States)

2010-04-01

..., reptiles, mollusks, and crustaceans; prohibited and endangered and threatened species; designated ports of..., Birds, and Insects § 12.26 Importations of wild animals, fish, amphibians, reptiles, mollusks, and... crustacea), amphibians, reptiles, or the offspring or eggs of any of the foregoing which the Secretary of...

Dynamics of radionuclide accumulation at amphibians and reptiles in the Poles'e state radioecological reserve

International Nuclear Information System (INIS)

Novitskij, R.V.

1998-01-01

It was studied the peculiarity of the radionuclide intake to organism of amphibians and reptiles in the Poles'e radioecological reserve in 1997. The radioactive contamination level of investigated area was from 15 to 40 Ci/km 2 . It was measured 38 samples (26 for amphibians and 12 for reptiles) from points with background gamma-irradiation from 35 to 800 micro R/h. For the last eleven years of investigation it was revealed the total tendency to reduction of level of gamma-radioactive accumulation in 18,8-42,6 times for amphibians and in 2,8-52,5 times for reptiles

A conceptual model to facilitate amphibian conservation in the northern Great Plains

Science.gov (United States)

Mushnet, David M.; Euliss, Ned H.; Stockwell, Craig A.

2012-01-01

As pressures on agricultural landscapes to meet worldwide resource needs increase, amphibian populations face numerous threats including habitat destruction, chemical contaminants, disease outbreaks, wetland sedimentation, and synergistic effects of these perturbations. To facilitate conservation planning, we developed a conceptual model depicting elements critical for amphibian conservation in the northern Great Plains. First, we linked upland, wetland, and landscape features to specific ecological attributes. Ecological attributes included adult survival; reproduction and survival to metamorphosis; and successful dispersal and recolonization. Second, we linked ecosystem drivers, ecosystem stressors, and ecological effects of the region to each ecological attribute. Lastly, we summarized information on these ecological attributes and the drivers, stressors, and effects that work in concert to influence the maintenance of viable and genetically diverse amphibian populations in the northern Great Plains. While our focus was on the northern Great Plains, our conceptual model can be tailored to other geographic regions and taxa.

Effects of pollution on freshwater fish and amphibians

International Nuclear Information System (INIS)

Pickering, Q.H.; Hunt, E.P.; Phipps, G.L.; Roush, T.H.; Smith, W.E.; Spehar, D.L.; Stephan, C.E.; Tanner, D.K.

1983-01-01

A literature review is presented dealing with studies on the effects of pollution on freshwater fish and amphibians. The pollutants studied included acid mine drainage, PCBs, cadmium, lead, naphthalene, plutonium, in addition to several studies dealing with pH effects

A strategy for monitoring and managing declines in an amphibian community.

Science.gov (United States)

Grant, Evan H Campbell; Zipkin, Elise F; Nichols, James D; Campbell, J Patrick

2013-12-01

Although many taxa have declined globally, conservation actions are inherently local. Ecosystems degrade even in protected areas, and maintaining natural systems in a desired condition may require active management. Implementing management decisions under uncertainty requires a logical and transparent process to identify objectives, develop management actions, formulate system models to link actions with objectives, monitor to reduce uncertainty and identify system state (i.e., resource condition), and determine an optimal management strategy. We applied one such structured decision-making approach that incorporates these critical elements to inform management of amphibian populations in a protected area managed by the U.S. National Park Service. Climate change is expected to affect amphibian occupancy of wetlands and to increase uncertainty in management decision making. We used the tools of structured decision making to identify short-term management solutions that incorporate our current understanding of the effect of climate change on amphibians, emphasizing how management can be undertaken even with incomplete information. Estrategia para Monitorear y Manejar Disminuciones en una Comunidad de Anfibios. © 2013 Society for Conservation Biology.

Pentastomiasis and other parasitic zoonoses from reptiles and amphibians.

Science.gov (United States)

Pantchev, Nikola; Tappe, Dennis

2011-01-01

Reptiles are growing in popularity as pets.The colonization of reptiles and amphibians by parasites and the resulting disease conditions are the most common problems seen in captive animals.This review focuses on pentastomiasis and sparganosis, important parasitic zoonoses of reptiles and amphibians, respectively, and free living-amoebae. Humans are suitable accidental hosts for some pentastomid species (particularly Armillifer and Porocephalus). In geographical areas with special ethnics, such as in West and Central Africa, and East Asia, 8-45% of the human population can be affected. Usually the larvae are coincidentally found during abdominal surgeries. However, fatalities have been described. Extreme caution is necessary when handling infected reptiles. Ocular or cerebral sparganosis is not uncommonly found in humans in East Asia. This disease is caused by spargana, tapeworm larvae (plerocercoids) of Spirometra sp. The infection occurs when uncooked meat from reptiles or amphibians is applied to wounds or eyes and the parasites migrate directly to human tissue, or by consumption of contaminated food or water. As a consequence of the reptile's predatory behaviour, the full spectrum of endo- and ectoparasites from potential prey animals can be found as transiting parasites in the intestinal tract, e. g. Hymenolepis nana, Cryptosporidium (C.) muris, C parvum or Capillaria hepatica. Occasionally, free-living amoebae are also found in reptile faeces (Acanthamoeba, Naegleria, Hartmanella, Vahlkampfia or Echinamoeba sp.).

AMPHIBIAN DECLINE, ULTRAVIOLET RADIATION AND LOCAL POPULATION ADAPTATION

Science.gov (United States)

Amphibian population declines have been noted on both local and global scales. Causes for these declines are unknown although many hypotheses have been offered. In areas adjacent to human development, loss of habitat is a fairly well accepted cause. However in isolated, seemingl...

OPTICAL CHARACTERISTICS OF NATURAL WATERS PROTECT AMPHIBIAN POPULATIONS FROM UV-B IN THE US PACIFIC NORTHWEST

Science.gov (United States)

Increased exposure to ultraviolet-B (UV-B) radiation has been proposed as a major environmental stressor leading to global amphibian declines. Prior experimental evidence from the US Pacific Northwest (PNW) indicating the acute embryonic sensitivity of at least 4 amphibian specie...

Sampling methods for terrestrial amphibians and reptiles.

Science.gov (United States)

Paul Stephen Corn; R. Bruce. Bury

1990-01-01

Methods described for sampling amphibians and reptiles in Douglas-fir forests in the Pacific Northwest include pitfall trapping, time-constrained collecting, and surveys of coarse woody debris. The herpetofauna of this region differ in breeding and nonbreeding habitats and vagility, so that no single technique is sufficient for a community study. A combination of...

Biogeography of amphibians and reptiles in Arizona

Science.gov (United States)

Eric W. Stitt; Theresa M. Mau-Crimmins; Don E. Swann

2005-01-01

We examined patterns of species richness for amphibians and reptiles in Arizona and evaluated patterns in species distribution between ecoregions based on species range size. In Arizona, the Sonoran Desert has the highest herpetofauna diversity, and the southern ecoregions are more similar than other regions. There appear to be distinct low- and mid-elevational...

Digestive Phenotypic Flexibility in Post-Metamorphic Amphibians: Studies on a Model Organism

Directory of Open Access Journals (Sweden)

DANIEL E NAYA

2004-01-01

Full Text Available Studies of phenotypic flexibility are central to the understanding of evolutionary and comparative physiology. Research conducted on many vertebrate species has shown that the digestive system is highly responsive and sensitive to environmental cues. However, amphibians, which are a standard and classic model organism for the study of many physiological processes, have been poorly considered in the study of ecological consequences on digestive flexibility. Here we review and analyze the current information on this topic for amphibians. We identify three major bodies of empirical evidence: a seasonal changes in gut development, b lack of dietary modulation of gut attributes in adult individuals, c a relationship between feeding habits and the magnitude of digestive performance regulation. Once the natural history characteristics of the species under study are taken into account, all the evidence is in full agreement with the predictions of digestive theory. We propose that evolutionary and comparative physiology could benefit greatly from the study of phenotypic flexibility in amphibians

Amphibians and Reptiles of the state of Nuevo León, Mexico.

Science.gov (United States)

Lemos-Espinal, Julio A; Smith, Geoffrey R; Cruz, Alexander

2016-01-01

We compiled a check list of the herpetofauna of Nuevo León. We documented 132 species (23 amphibians, 109 reptiles), representing 30 families (11 amphibians, 19 reptiles) and 73 genera (17 amphibians, 56 reptiles). Only two species are endemic to Nuevo León. Nuevo León contains a relatively high richness of lizards in the genus Sceloporus. Overlap in the herpetofauna of Nuevo León and states it borders is fairly extensive. Of 130 native species, 102 are considered species of Least Concern in the IUCN red list, four are listed as Vulnerable, five are listed as Near Threatened, and four are listed as Endangered. According to SEMARNAT, 78 species are not of conservation concern, 25 are subject to Special Protection, 27 are Threatened, and none are listed as in Danger of Extinction. Given current threats to the herpetofauna, additional efforts to understand the ecology and status of populations in Nuevo León are needed.

Practitioner and scientist perceptions of successful amphibian conservation.

Science.gov (United States)

Meredith, Helen M R; St John, Freya A V; Collen, Ben; Black, Simon A; Griffiths, Richard A

2018-04-01

Conservation requires successful outcomes. However, success is perceived in many different ways depending on the desired outcome. Through a questionnaire survey, we examined perceptions of success among 355 scientists and practitioners working on amphibian conservation from over 150 organizations in more than 50 countries. We also sought to identify how different types of conservation actions and respondent experience and background influenced perceptions. Respondents identified 4 types of success: species and habitat improvements (84% of respondents); effective program management (36%); outreach initiatives such as education and public engagement (25%); and the application of science-based conservation (15%). The most significant factor influencing overall perceived success was reducing threats. Capacity building was rated least important. Perceptions were influenced by experience, professional affiliation, involvement in conservation practice, and country of residence. More experienced practitioners associated success with improvements to species and habitats and less so with education and engagement initiatives. Although science-based conservation was rated as important, this factor declined in importance as the number of programs a respondent participated in increased, particularly among those from less economically developed countries. The ultimate measure of conservation success-population recovery-may be difficult to measure in many amphibians; difficult to relate to the conservation actions intended to drive it; and difficult to achieve within conventional funding time frames. The relaunched Amphibian Conservation Action Plan provides a framework for capturing lower level processes and outcomes, identifying gaps, and measuring progress. © 2017 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Forest Fragments Surrounded by Sugar Cane Are More Inhospitable to Terrestrial Amphibian Abundance Than Fragments Surrounded by Pasture

Directory of Open Access Journals (Sweden)

Paula Eveline Ribeiro D’Anunciação

2013-01-01

Full Text Available In recent years, there has been increasing interest in matrix-type influence on forest fragments. Terrestrial amphibians are good bioindicators for this kind of research because of low vagility and high philopatry. This study compared richness, abundance, and species composition of terrestrial amphibians through pitfall traps in two sets of semideciduous seasonal forest fragments in southeastern Brazil, according to the predominant surrounding matrix (sugar cane and pasture. There were no differences in richness, but fragments surrounded by sugar cane had the lowest abundance of amphibians, whereas fragments surrounded by pastures had greater abundance. The most abundant species, Rhinella ornata, showed no biometric differences between fragment groups but like many other amphibians sampled showed very low numbers of individuals in fragments dominated by sugar cane fields. Our data indicate that the sugar cane matrix negatively influences the community of amphibians present in fragments surrounded by this type of land use.

Development and application of an eDNA method to detect and quantify a pathogenic parasite in aquatic ecosystems.

Science.gov (United States)

Huver, J R; Koprivnikar, J; Johnson, P T J; Whyard, S

2015-06-01

Approaches based on organismal DNA found in the environment (eDNA) have become increasingly utilized for ecological studies and biodiversity inventories as an alternative to traditional field survey methods. Such DNA-based techniques have largely been used to establish the presence of free-living organisms, but have much potential for detecting and quantifying infectious agents in the environment, which is necessary to evaluate disease risk. We developed an eDNA method to examine the distribution and abundance of the trematode Ribeiroia ondatrae, a pathogenic parasite known to cause malformations in North American amphibians. In addition to comparing this eDNA approach to classical host necropsy, we examined the detectability of R. ondatrae in water samples subject to different degradation conditions (time and temperature). Our test exhibited high specificity and sensitivity to R. ondatrae, capable of detecting as little as 14 fg (femtograms) of this parasite's DNA (1/2500th of a single infectious stage) from field water samples. Compared to our results from amphibian host necropsy, quantitative PCR was -90% concordant with respect to R. ondatrae detection from 15 field sites and was also a significant predictor of host infection abundance. DNA was still detectable in lab samples after 21 days at 25°C, indicating that our method is robust to field conditions. By comparing the advantages and disadvantages of eDNA vs. traditional survey methods for determining pathogen presence and abundance in the field, we found that the lower cost and effort associated with eDNA approaches provide many advantages. The development of alternative tools is critical for disease ecology, as wildlife management and conservation efforts require reliable establishment and monitoring of pathogens.

Can we enhance amphibians' habitat restoration in the post-mining areas?

Science.gov (United States)

Klimaszewski, Krzysztof; Pacholik, Ewa; Snopek, Adam

2016-09-01

The study was aimed to evaluate the selected improvements of nature restoration in a depleted gravel pit. The study site consisted of four water reservoirs of different shapes and sizes, flooded after the gravel extraction ended. Ecological succession monitoring, conducted by the Warsaw University of Life Sciences students associated in the Student Scientific Association of Animal Sciences Faculty since the completion of mining, have focused on amphibians. A twofold approach upheld amphibian species population dynamics, as well as selected habitat elements. The restoration practices dedicated to habitat conditions enhancing have been proved to be definitely effective and useful for similar sites.

Bent's Old Fort: Amphibians and Reptiles

Science.gov (United States)

Muths, E.

2008-01-01

Bent's Old Fort National Historic Site sits along the Arkansas River in the semi-desert prairie of southeastern Colorado. The USGS provided assistance in designing surveys to assess the variety of herpetofauna (amphibians and reptiles) resident at this site. This brochure is the results of those efforts and provides visitors with information on what frogs, toads, snakes and salamanders might be seen and heard at Bent's Old Fort.

Evidence for the persistence of food web structure after amphibian extirpation in a Neotropical stream.

Science.gov (United States)

Barnum, Thomas R; Drake, John M; Colón-Gaud, Checo; Rugenski, Amanda T; Frauendorf, Therese C; Connelly, Scott; Kilham, Susan S; Whiles, Matt R; Lips, Karen R; Pringle, Catherine M

2015-08-01

Species losses are predicted to simplify food web structure, and disease-driven amphibian declines in Central America offer an opportunity to test this prediction. Assessment of insect community composition, combined with gut content analyses, was used to generate periphyton-insect food webs for a Panamanian stream, both pre- and post-amphibian decline. We then used network analysis to assess the effects of amphibian declines on food web structure. Although 48% of consumer taxa, including many insect taxa, were lost between pre- and post-amphibian decline sampling dates, connectance declined by less than 3%. We then quantified the resilience of food web structure by calculating the number of expected cascading extirpations from the loss of tadpoles. This analysis showed the expected effects of species loss on connectance and linkage density to be more than 60% and 40%, respectively, than were actually observed. Instead, new trophic linkages in the post-decline food web reorganized the food web topology, changing the identity of "hub" taxa, and consequently reducing the effects of amphibian declines on many food web attributes. Resilience of food web attributes was driven by a combination of changes in consumer diets, particularly those of insect predators, as well as the appearance of generalist insect consumers, suggesting that food web structure is maintained by factors independent of the original trophic linkages.

Book review: Reptiles and amphibians: Self-assessment color review

Science.gov (United States)

Green, David E.

2017-01-01

No abstract available.Book information: Reptiles and Amphibians: Self-Assessment Color Review. 2nd Edition. By Fredric L. Frye. CRC Press, Taylor and Francis Group, Boca Raton, Florida USA. 2015. 252 pp. ISBN 9781482257601.

Parasitic infections of amphibians in the Pendjari Biosphere ...

African Journals Online (AJOL)

Parasitic infections of amphibians in the Pendjari Biosphere Reserve, Benin. ... Results obtained show the possible influence of land-use pattern on parasite distribution. For example, the ... Furthermore, this infection pattern may be indicative of an immunosuppressive effect of pesticides on the frogs of the Agricultural Zone.

Amphibian responses to wildfire in the western united states: Emerging patterns from short-term studies

Science.gov (United States)

Hossack, B.R.; Pilliod, D.S.

2011-01-01

The increased frequency and severity of large wildfires in the western United States is an important ecological and management issue with direct relevance to amphibian conservation. Although the knowledge of fire effects on amphibians in the region is still limited relative to most other vertebrate species, we reviewed the current literature to determine if there are evident patterns that might be informative for conservation or management strategies. Of the seven studies that compared pre- and post-wildfire data on a variety of metrics, ranging from amphibian occupancy to body condition, two reported positive responses and five detected negative responses by at least one species. Another seven studies used a retrospective approach to compare effects of wildfire on populations: two studies reported positive effects, three reported negative effects from wildfire, and two reported no effects. All four studies that included plethodontid salamanders reported negative effects on populations or individuals; these effects were greater in forests where fire had been suppressed and in areas that burned with high severity. Species that breed in streams are also vulnerable to post-wildfire changes in habitat, especially in the Southwest. Wildfire is also important for maintaining suitable habitat for diverse amphibian communities, although those results may not be evident immediately after an area burns. We expect that wildfire will extirpate few healthy amphibian populations, but it is still unclear how populations will respond to wildfire in the context of land management (including pre- and post-fire timber harvest) and fragmentation. Wildfire may also increase the risk of decline or extirpation for small, isolated, or stressed (e.g., from drought or disease) populations. Improved understanding of how these effects vary according to changes in fire frequency and severity are critical to form more effective conservation strategies for amphibians in the western United States.

Toxicity of road salt to Nova Scotia amphibians.

Science.gov (United States)

Collins, Sara J; Russell, Ronald W

2009-01-01

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC(50)) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species.

Conservation genetics and genomics of amphibians and reptiles.

Science.gov (United States)

Shaffer, H Bradley; Gidiş, Müge; McCartney-Melstad, Evan; Neal, Kevin M; Oyamaguchi, Hilton M; Tellez, Marisa; Toffelmier, Erin M

2015-01-01

Amphibians and reptiles as a group are often secretive, reach their greatest diversity often in remote tropical regions, and contain some of the most endangered groups of organisms on earth. Particularly in the past decade, genetics and genomics have been instrumental in the conservation biology of these cryptic vertebrates, enabling work ranging from the identification of populations subject to trade and exploitation, to the identification of cryptic lineages harboring critical genetic variation, to the analysis of genes controlling key life history traits. In this review, we highlight some of the most important ways that genetic analyses have brought new insights to the conservation of amphibians and reptiles. Although genomics has only recently emerged as part of this conservation tool kit, several large-scale data sources, including full genomes, expressed sequence tags, and transcriptomes, are providing new opportunities to identify key genes, quantify landscape effects, and manage captive breeding stocks of at-risk species.

Ecological Risk Assessment of Perchlorate in Avian Species, Rodents, Amphibians and Fish: FY2003

Science.gov (United States)

2005-10-01

Ecological Receptors at the Longhorn Army Ammunition Plant (LHAAP), Karnack, TX. Ecotoxicology , 10: 305-313. Smith JN, Pan X, Gentles, BA, Smith...Page 32 of 225 Hayes, TB. 2000. Endocrine disruption in amphibians. In Sparling DW, Linder G, Bishop C, eds. Ecotoxicology of Amphibians and... macrophytes and was programmed in Matlab using difference equations. To simulate and predict the uptake and transport of explosives in various

Reptiles and amphibians

Science.gov (United States)

Lovich, Jeffrey E.; Ennen, Joshua R.; Perrow, Martin

2017-01-01

Summary – We reviewed all the peer-reviewed scientific publications we could find on the known and potential effects of wind farm development, operation, maintenance, and decommissioning on reptiles and amphibians (collectively herpetofauna) worldwide. Both groups are declining globally due to a multitude of threats including energy development. Effect studies were limited to the long-term research by the authors on Agassiz’s Desert Tortoise ecology and behavior at single operational wind farm in California, US and an analysis of the effects of wind farm installation on species richness of vertebrates including reptiles and amphibians in northwestern Portugal. Research on Agassiz’s Desert Tortoise found few demonstrable differences in biological parameters between populations in the wind farm and those in more natural habitats. High reproductive output is due to the regional climate and not to the presence or operation of the wind farm. Site operations have resulted in death and injury to a small number of adult tortoises and over the long-term tortoises now appear to avoid the areas of greatest turbine concentration. Research in Portugal using models and simulations based on empirical data show that vertebrate species richness (including herpetofauna) decreased by almost 20% after the installation of only two large monopole turbines per 250 x 250 m plot. Knowledge of the known responses of herpetofauna to various disturbances allows identification of potential impacts from construction material acquisition in offsite areas, mortality and stress due to impacts of roads and related infrastructure, destruction and modification of habitat, habitat fragmentation and barriers to gene flow, noise, vibration, electromagnetic field generation, heat from buried high voltage transmission lines, alteration of local and regional climate, predator attraction, and increased risk of fire. Research on herpetofauna lags far behind what is needed and, in particular, before

Garter snakes distributions in high elevation aquatic ecosystems: Is there a link with declining amphibian populations and nonnative trout introductions?

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K.R. Matthews; R.A. Knapp; K.L. Pope

2002-01-01

ABSTRACT.—The dramatic amphibian population declines reported worldwide likely have important effects on their predators. In the Sierra Nevada, where amphibian declines are well documented and some are closely tied to the introduction of nonnative trout, the mountain garter snake, Thamnophis elegans elegans, preys predominately on amphibians. We surveyed 2103 high-...

Skin swabs with FTA® cards as a dry storage source for amphibian DNA

OpenAIRE

Ward, A; Hide, G; Jehle, R

2018-01-01

Amphibians are the most endangered group of vertebrates, and conservation measures increasingly rely on information drawn from genetic markers. The present study explores skin swabs with Whatman FTA® cards as a method to retrieve PCR-amplifiable amphibian DNA. Swabs from ten adult great crested newts (Triturus cristatus) were used to compare FTA® card-based protocols with tissue sampling based on toe clips. PCR success rates were measured for seven microsatellite markers and one mtDNA marker ...

A new parameterization for integrated population models to document amphibian reintroductions.

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Duarte, Adam; Pearl, Christopher A; Adams, Michael J; Peterson, James T

2017-09-01

Managers are increasingly implementing reintroduction programs as part of a global effort to alleviate amphibian declines. Given uncertainty in factors affecting populations and a need to make recurring decisions to achieve objectives, adaptive management is a useful component of these efforts. A major impediment to the estimation of demographic rates often used to parameterize and refine decision-support models is that life-stage-specific monitoring data are frequently sparse for amphibians. We developed a new parameterization for integrated population models to match the ecology of amphibians and capitalize on relatively inexpensive monitoring data to document amphibian reintroductions. We evaluate the capability of this model by fitting it to Oregon spotted frog (Rana pretiosa) monitoring data collected from 2007 to 2014 following their reintroduction within the Klamath Basin, Oregon, USA. The number of egg masses encountered and the estimated adult and metamorph abundances generally increased following reintroduction. We found that survival probability from egg to metamorph ranged from 0.01 in 2008 to 0.09 in 2009 and was not related to minimum spring temperatures, metamorph survival probability ranged from 0.13 in 2010-2011 to 0.86 in 2012-2013 and was positively related to mean monthly temperatures (logit-scale slope = 2.37), adult survival probability was lower for founders (0.40) than individuals recruited after reintroduction (0.56), and the mean number of egg masses per adult female was 0.74. Our study is the first to test hypotheses concerning Oregon spotted frog egg-to-metamorph and metamorph-to-adult transition probabilities in the wild and document their response at multiple life stages following reintroduction. Furthermore, we provide an example to illustrate how the structure of our integrated population model serves as a useful foundation for amphibian decision-support models within adaptive management programs. The integration of multiple, but

Amphibian diversity and threatened species in a severely transformed neotropical region in Mexico.

Science.gov (United States)

Meza-Parral, Yocoyani; Pineda, Eduardo

2015-01-01

Many regions around the world concentrate a large number of highly endangered species that have very restricted distributions. The mountainous region of central Veracruz, Mexico, is considered a priority area for amphibian conservation because of its high level of endemism and the number of threatened species. The original tropical montane cloud forest in the region has been dramatically reduced and fragmented and is now mainly confined to ravines and hillsides. We evaluated the current situation of amphibian diversity in the cloud forest fragments of this region by analyzing species richness and abundance, comparing assemblage structure and species composition, examining the distribution and abundance of threatened species, and identifying the local and landscape variables associated with the observed amphibian diversity. From June to October 2012 we sampled ten forest fragments, investing 944 person-hours of sampling effort. A total of 895 amphibians belonging to 16 species were recorded. Notable differences in species richness, abundance, and assemblage structure between forest fragments were observed. Species composition between pairs of fragments differed by an average of 53%, with the majority (58%) resulting from species replacement and the rest (42%) explained by differences in species richness. Half of the species detected are under threat of extinction according to the International Union for Conservation of Nature, and although their distribution and abundance varied markedly, there were also ubiquitous and abundant species, along with rare species of restricted distribution. The evident heterogeneity of the ten study sites indicates that to conserve amphibians in a mountainous region such as this one it is necessary to protect groups of fragments which represent the variability of the system. Both individually and together cloud forest fragments are very important to conservation because each remnant is inhabited by several threatened species, some of

Cell size is positively correlated between different tissues in passerine birds and amphibians, but not necessarily in mammals

OpenAIRE

Kozłowski, J.; Czarnołęski, M.; François-Krassowska, A.; Maciak, S.; Pis, T.

2010-01-01

We examined cell size correlations between tissues, and cell size to body mass relationships in passerine birds, amphibians and mammals. The size correlated highly between all cell types in birds and amphibians; mammalian tissues clustered by size correlation in three tissue groups. Erythrocyte size correlated well with the volume of other cell types in birds and amphibians, but poorly in mammals. In birds, body mass correlated positively with the size of all cell types including erythrocytes...

Predicting breeding habitat for amphibians: a spatiotemporal analysis across Yellowstone National Park.

Science.gov (United States)

Bartelt, Paul E; Gallant, Alisa L; Klaver, Robert W; Wright, Chris K; Patla, Debra A; Peterson, Charles R

2011-10-01

The ability to predict amphibian breeding across landscapes is important for informing land management decisions and helping biologists better understand and remediate factors contributing to declines in amphibian populations. We built geospatial models of likely breeding habitats for each of four amphibian species that breed in Yellowstone National Park (YNP). We used field data collected in 2000-2002 from 497 sites among 16 basins and predictor variables from geospatial models produced from remotely sensed data (e.g., digital elevation model, complex topographic index, landform data, wetland probability, and vegetative cover). Except for 31 sites in one basin that were surveyed in both 2000 and 2002, all sites were surveyed once. We used polytomous regression to build statistical models for each species of amphibian from (1) field survey site data only, (2) field data combined with data from geospatial models, and (3) data from geospatial models only. Based on measures of receiver operating characteristic (ROC) scores, models of the second type best explained likely breeding habitat because they contained the most information (ROC values ranged from 0.70 to 0.88). However, models of the third type could be applied to the entire YNP landscape and produced maps that could be verified with reserve field data. Accuracy rates for models built for single years were highly variable, ranging from 0.30 to 0.78. Accuracy rates for models built with data combined from multiple years were higher and less variable, ranging from 0.60 to 0.80. Combining results from the geospatial multiyear models yielded maps of "core" breeding areas (areas with high probability values for all three years) surrounded by areas that scored high for only one or two years, providing an estimate of variability among years. Such information can highlight landscape options for amphibian conservation. For example, our models identify alternative areas that could be protected for each species

Effects of atrazine on embryos, larvae, and adults of anuran amphibians.

Science.gov (United States)

Allran, J W; Karasov, W H

2001-04-01

We examined the effects of atrazine (0-20 mg/L) on embryos, larvae, and adult anuran amphibian species in the laboratory. Atrazine treatments did not affect hatchability of embryos or 96-h posthatch mortality of larvae of Rana pipiens, Rana sylvatica, or Bufo americanus. Furthermore, atrazine had no effect on swimming speed (measured for R. pipiens only). However, there was a dose-dependent increase in deformed larvae of all three species with increasing atrazine concentration. In adult R. pipiens, atrazine increased buccal and thoracic ventilation, indicating respiratory distress. However, because atrazine had no affect on hemoglobin, this respiratory distress was probably not indicative of reduced oxygen-carrying capacity of the blood. Frogs exposed to the highest atrazine concentration stopped eating immediately after treatment began and did not eat during the 14-d experiment. However, no decreases in mass were measured even for frogs that were not eating, probably because of compensatory fluid gain from edema. Atrazine concentrations found to be deleterious to amphibian embryos and adults are considerably higher than concentrations currently found in surface waters in North America. Therefore, direct toxicity of atrazine is probably not a significant factor in recent amphibian declines.

Using Reptile and Amphibian Activities in the Classroom

Science.gov (United States)

Tomasek, Terry; Matthews, Catherine E.

2008-01-01

Reptiles and amphibians are a diverse and interesting group of organisms. The four activities described in this article take students' curiosity into the realm of scientific understanding. The activities involve the concepts of species identification; animal adaptations, communication, and habitat; and conservation. (Contains 1 table and 2…

Lung collapse among aquatic reptiles and amphibians during long-term diving.

Science.gov (United States)

Ultsch, Gordon R; Brainerd, Elizabeth L; Jackson, Donald C

2004-09-01

Numerous aquatic reptiles and amphibians that typically breathe both air and water can remain fully aerobic in normoxic (aerated) water by taking up oxygen from the water via extrapulmonary avenues. Nevertheless, if air access is available, these animals do breathe air, however infrequently. We suggest that such air breathing does not serve an immediate gas exchange function under these conditions, nor is it necessarily related to buoyancy requirements, but serves to keep lungs inflated that would otherwise collapse during prolonged submergence. We also suggest that lung deflation is routine in hibernating aquatic reptiles and amphibians in the northern portions of their ranges, where ice cover prevents surfacing for extended periods.

Climatic change and wetland desiccation cause amphibian decline in Yellowstone National Park.

Science.gov (United States)

McMenamin, Sarah K; Hadly, Elizabeth A; Wright, Christopher K

2008-11-04

Amphibians are a bellwether for environmental degradation, even in natural ecosystems such as Yellowstone National Park in the western United States, where species have been actively protected longer than anywhere else on Earth. We document that recent climatic warming and resultant wetland desiccation are causing severe declines in 4 once-common amphibian species native to Yellowstone. Climate monitoring over 6 decades, remote sensing, and repeated surveys of 49 ponds indicate that decreasing annual precipitation and increasing temperatures during the warmest months of the year have significantly altered the landscape and the local biological communities. Drought is now more common and more severe than at any time in the past century. Compared with 16 years ago, the number of permanently dry ponds in northern Yellowstone has increased 4-fold. Of the ponds that remain, the proportion supporting amphibians has declined significantly, as has the number of species found in each location. Our results indicate that climatic warming already has disrupted one of the best-protected ecosystems on our planet and that current assessments of species' vulnerability do not adequately consider such impacts.

Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change

Science.gov (United States)

Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

2014-01-01

Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data. PMID:24454550

Streamside zone width and amphibian and reptile abundance

Science.gov (United States)

D. Craig Rudolph; James G. Dickson

1990-01-01

Many natural pine-hardwood stands in the southeastern United States are being converted to pine plantations with short rotations. This forest conversion alters vertebrate communities, particularly amphibians and reptiles (Bennett et al., 1980; Rakowitz, 1983). One practice in stand conversion to accommodate vertebrate species is the retention of strips of unharvested,...

Engineering a future for amphibians under climate change

Science.gov (United States)

Luke P. Shoo; Deanna H. Olson; Sarah K. McMenamin; Kris A. Murray; Monique VanSluys; Maureen A. Donnelly; Danial Stratford; Juhani Terhivuo; Andres Merino-Viteri; Sarah M. Herbert; Phillip J. Bishop; Paul Stephen Corn; Liz Dovey; Richard A. Griffiths; Katrin Lowe; Michael Mahony; Hamish McCallum; Jonathan D. Shuker; Clay Simpkins; Lee F. Skerratt; Stephen E. Williams; Jean-Marc Hero

2011-01-01

Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were...

Plasticity and Adult Neurogenesis in Amphibians and Reptiles: More Questions than Answers.

Science.gov (United States)

Powers, Alice Schade

2016-08-24

Studies of the relationship between behavioral plasticity and new cells in the adult brain in amphibians and reptiles are sparse but demonstrate that environmental and hormonal variables do have an effect on the amount of cell proliferation and/or migration. The variables that are reviewed here are: enriched environment, social stimulation, spatial area use, season, photoperiod and temperature, and testosterone. Fewer data are available for amphibians than for reptiles, but for both groups many issues are still to be resolved. It is to be hoped that the questions raised here will generate more answers in future studies. © 2016 S. Karger AG, Basel.

Amphibian Declines Are Not Uniquely High amongst the Vertebrates: Trend Determination and the British Perspective

Directory of Open Access Journals (Sweden)

John Buckley

2009-09-01

Full Text Available Although amphibians have experienced major global declines and an increasing extinction rate, recent results indicate that they are not as uniquely disadvantaged as previously supposed. Acquisition of robust data is evidently crucial to the determination of both absolute and relative rates of biodiversity declines, and thus in prioritising conservation actions. In Britain there is arguably a longer history of recording, and attempting to conserve, a wide range of species groups than anywhere else in the world. This stems from the early activities of Victorian naturalists in the nineteenth century, the establishment of natural history societies and, since the mid-twentieth century, a range of national recording schemes and organisations actively involved in conservation. In this review we summarise comparative evidence for British amphibians and reptiles concerning historical abundance, population trends and their causes, and outline how they relate to the situation elsewhere in Europe (and possibly the World. We discuss possible reasons why the plight of ectothermic vertebrates (fish, amphibians and reptiles seems generally worse than that of endotherms (birds and mammals, as well as research priorities and factors likely to impact amphibians and reptile conservation in future.

Do hormone-modulating chemicals impact on reproduction and development of wild amphibians?

Science.gov (United States)

Orton, Frances; Tyler, Charles R

2015-11-01

Globally, amphibians are undergoing a precipitous decline. At the last estimate in 2004, 32% of the approximately 6000 species were threatened with extinction and 43% were experiencing significant declines. These declines have been linked with a wide range of environmental pressures from habitat loss to climate change, disease and pollution. This review evaluates the evidence that endocrine-disrupting contaminants (EDCs) - pollutants that affect hormone systems - are impacting on wild amphibians and contributing to population declines. The review is limited to anurans (frogs and toads) as data for effects of EDCs on wild urodeles (salamanders, newts) or caecilians (limbless amphibians) are extremely limited. Evidence from laboratory studies has shown that a wide range of chemicals have the ability to alter hormone systems and affect reproductive development and function in anurans, but for the most part only at concentrations exceeding those normally found in natural environments. Exceptions can be found for exposures to the herbicide atrazine and polychlorinated biphenyls in leopard frogs (Rana pipiens) and perchlorate in African clawed frogs (Xenopus laevis). These contaminants induce feminising effects on the male gonads (including 'intersex' - oocytes within testes) at concentrations measured in some aquatic environments. The most extensive data for effects of an EDC in wild amphibian populations are for feminising effects of atrazine on male gonad development in regions across the USA. Even where strong evidence has been provided for feminising effects of EDCs, however, the possible impact of these effects on fertility and breeding outcome has not been established, making inference for effects on populations difficult. Laboratory studies have shown that various chemicals, including perchlorate, polychlorinated biphenyls and bromodiphenylethers, also act as endocrine disrupters through interfering with thyroid-dependent processes that are fundamental for

Coastal Resources Atlas: Long Island: REPTILES (Reptile and Amphibian Polygons)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles, estuarine turtles, and amphibians for Long Island, New York. Vector polygons in this data...

Fetal adaptations for viviparity in amphibians.

Science.gov (United States)

Wake, Marvalee H

2015-08-01

Live-bearing has evolved in all three orders of amphibians--frogs, salamanders, and caecilians. Developing young may be either yolk dependent, or maternal nutrients may be supplied after yolk is resorbed, depending on the species. Among frogs, embryos in two distantly related lineages develop in the skin of the maternal parents' backs; they are born either as advanced larvae or fully metamorphosed froglets, depending on the species. In other frogs, and in salamanders and caecilians, viviparity is intraoviductal; one lineage of salamanders includes species that are yolk dependent and born either as larvae or metamorphs, or that practice cannibalism and are born as metamorphs. Live-bearing caecilians all, so far as is known, exhaust yolk before hatching and mothers provide nutrients during the rest of the relatively long gestation period. The developing young that have maternal nutrition have a number of heterochronic changes, such as precocious development of the feeding apparatus and the gut. Furthermore, several of the fetal adaptations, such as a specialized dentition and a prolonged metamorphosis, are homoplasious and present in members of two or all three of the amphibian orders. At the same time, we know little about the developmental and functional bases for fetal adaptations, and less about the factors that drive their evolution and facilitate their maintenance. © 2014 Wiley Periodicals, Inc.

Ovarian control and monitoring in amphibians.

Science.gov (United States)

Calatayud, N E; Stoops, M; Durrant, B S

2018-03-15

Amphibian evolution spans over 350 million years, consequently this taxonomic group displays a wide, complex array of physiological adaptations and their diverse modes of reproduction are a prime example. Reproduction can be affected by taxonomy, geographic and altitudinal distribution, and environmental factors. With some exceptions, amphibians can be categorized into discontinuous (strictly seasonal) and continuous breeders. Temperature and its close association with other proximate and genetic factors control reproduction via a tight relationship with circadian rhythms which drive genetic and hormonal responses to the environment. In recent times, the relationship of proximate factors and reproduction has directly or indirectly lead to the decline of this taxonomic group. Conservationists are tackling the rapid loss of species through a wide range of approaches including captive rescue. However, there is still much to be learned about the mechanisms of reproductive control and its requirements in order to fabricate species-appropriate captive environments that address a variety of reproductive strategies. As with other taxonomic groups, assisted reproductive technologies and other reproductive monitoring tools such as ultrasound, hormone analysis and body condition indices can assist conservationists in optimizing captive husbandry and breeding. In this review we discuss some of the mechanisms of ovarian control and the different tools being used to monitor female reproduction. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of the Chytrid fungus on the Tarahumara frog (Rana tarahumarae) in Arizona and Sonora, Mexico

Science.gov (United States)

Stephen F. Hale; Philip C. Rosen; James L. Jarchow; Gregory A. Bradley

2005-01-01

We conducted histological analyses on museum specimens collected 1975-1999 from 10 sites in Arizona and Sonora to test for the pathogenic chytrid fungus (Batrachochytrium dendrobatidis) in ranid frogs, focusing on the Tarahumara frog (Rana tarahumarae). During 1981-2000, frogs displaying disease signs were found in the field, and...

Phylogenetic signals in the climatic niches of the world's amphibians

DEFF Research Database (Denmark)

Hof, Christian; Rahbek, Carsten; Araújo, Miguel B.

2010-01-01

amphibian orders and across biogeographical regions. To our knowledge, this is the first study providing a comprehensive analysis of the phylogenetic signal in species climatic niches for an entire clade across the world. Even though our results do not provide a strong test of the niche conservatism......The question of whether closely related species share similar ecological requirements has attracted increasing attention, because of its importance for understanding global diversity gradients and the impacts of climate change on species distributions. In fact, the assumption that related species...... are also ecologically similar has often been made, although the prevalence of such a phylogenetic signal in ecological niches remains heavily debated. Here, we provide a global analysis of phylogenetic niche relatedness for the world's amphibians. In particular, we assess which proportion of the variance...

Microcosm investigations of stormwater pond sediment toxicity to embryonic and larval amphibians: Variation in sensitivity among species

Energy Technology Data Exchange (ETDEWEB)

Snodgrass, Joel W. [Department of Biological Sciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)], E-mail: jsnodgrass@towson.edu; Casey, Ryan E. [Department of Chemistry, Towson University, 8000 York Road, Towson, MD 21252 (United States); Joseph, Debra; Simon, Judith A. [Department of Biological Sciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)

2008-07-15

Stormwater ponds have become common features of modern development and often represent significant amounts of open space in urbanized areas. Although stormwater ponds may provide habitat for wildlife, factors responsible for producing variation in wildlife use of ponds have received limited attention. To investigate the role of variation in species tolerances of pollutants in structuring pond-breeding amphibian assemblages, we exposed species tolerant (Bufo americanus) and not tolerant (Rana sylvatica) of urbanization to pond sediments in laboratory microcosms. Pond microcosms had elevated sediment metal levels and chloride water concentrations. Among R. sylvatica embryos, exposure to pond sediments resulted in 100% mortality. In contrast, B. americanus embryos and larvae experienced only sublethal effects (i.e., reduced size at metamorphosis) due to pond sediment exposure. Our results suggest variation in pollutant tolerance among early developmental stages of amphibians may act in concert with terrestrial habitat availability to structure amphibian assemblages associated with stormwater ponds. - Variation among species in sensitivity to pollutants can influence stormwater pond amphibian assemblages.

Low levels of chemical anthropogenic pollution may threaten amphibians by impairing predator recognition.

Science.gov (United States)

Polo-Cavia, Nuria; Burraco, Pablo; Gomez-Mestre, Ivan

2016-03-01

Recent studies suggest that direct mortality and physiological effects caused by pollutants are major contributing factors to global amphibian decline. However, even sublethal concentrations of pollutants could be harmful if they combined with other factors to cause high mortality in amphibians. Here we show that sublethal concentrations of pollutants can disrupt the ability of amphibian larvae to recognize predators, hence increasing their risk of predation. This effect is indeed much more important since very low amounts of pollutants are ubiquitous, and environmental efforts are mostly directed towards preventing lethal spills. We analyzed the effects of two common contaminants (humic acid and ammonium nitrate) on the ability of tadpoles of the western spadefoot toad (Pelobates cultripes) to recognize chemical cues from a common predator, nymphs of the dragonfly Anax imperator. We compared the swimming activity of tadpoles in the presence and absence of water-borne chemical cues from dragonflies at different concentrations of humic acid and ammonium nitrate. Tadpoles reduced swimming activity in response to predator cues in the absence of pollutants, whereas they remained unresponsive to these cues when either humic acid or ammonium nitrate was added to the water, even at low concentrations. Moreover, changes in tadpole activity associated with the pollutants themselves were non-significant, indicating no toxic effect. Alteration of the natural chemical environment of aquatic systems by pollutants may be an important contributing cause for declines in amphibian populations, even at sublethal concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

A predictive framework and review of the ecological impacts of exotic plant invasions on reptiles and amphibians.

Science.gov (United States)

Martin, Leigh J; Murray, Brad R

2011-05-01

The invasive spread of exotic plants in native vegetation can pose serious threats to native faunal assemblages. This is of particular concern for reptiles and amphibians because they form a significant component of the world's vertebrate fauna, play a pivotal role in ecosystem functioning and are often neglected in biodiversity research. A framework to predict how exotic plant invasion will affect reptile and amphibian assemblages is imperative for conservation, management and the identification of research priorities. Here, we present a new predictive framework that integrates three mechanistic models. These models are based on exotic plant invasion altering: (1) habitat structure; (2) herbivory and predator-prey interactions; (3) the reproductive success of reptile and amphibian species and assemblages. We present a series of testable predictions from these models that arise from the interplay over time among three exotic plant traits (growth form, area of coverage, taxonomic distinctiveness) and six traits of reptiles and amphibians (body size, lifespan, home range size, habitat specialisation, diet, reproductive strategy). A literature review provided robust empirical evidence of exotic plant impacts on reptiles and amphibians from each of the three model mechanisms. Evidence relating to the role of body size and diet was less clear-cut, indicating the need for further research. The literature provided limited empirical support for many of the other model predictions. This was not, however, because findings contradicted our model predictions but because research in this area is sparse. In particular, the small number of studies specifically examining the effects of exotic plants on amphibians highlights the pressing need for quantitative research in this area. There is enormous scope for detailed empirical investigation of interactions between exotic plants and reptile and amphibian species and assemblages. The framework presented here and further testing of

Radioautographic investigation of retinal growth in mature amphibians

International Nuclear Information System (INIS)

Svistunov, S.A.; Mitashov, V.I.

1986-01-01

Growth of the retina was studied in mature intact amphibians, tritons, axolotls, ambystomas and clawed frogs, for six months using multiple injection of 3 H-thymidine. It was established that the source of replenishment of the retina by new cells is its terminal zone in all animals investigated. This is attested to by the gradual migration of labeled cells from the growth zone into differentiated layers of the retina. The most intensely labeled cells occupy a distal position relative to other labeled cells, therefore marking the boundary between the initial part of the retina, not containing labeled nuclei, and the part being augmented. For each species studied, a level of proliferative activity is characteristic for cells of the terminal zone, which decreases in the order axolotl-clawed frog-triton -ambystoma. In the axolotl and additional growth zone is noted in the retina, in addition to the terminal, which is located in the area of the unclosed section of the embryonic fissure. Results obtained serve as a basis for the regenerative potentials of eye tissues revealed previously in these amphibian species

Amphibian and reptile response to prescribed burning and thinning in pine-hardwood forests: pre-treatment results

Science.gov (United States)

William B. Sutton; Yong Wang; Callie J. Schweitzer

2010-01-01

Analysis of pretreatment data is essential to determine long-term effects of forest management on amphibians and reptiles. We present pre-treatment amphibian and reptile capture data from April 2005 to May 2006 for a long-term study on herpetofaunal response to prescribed burning and tree thinning in the William B. Bankhead National Forest, AL, United States....

Quaternary climate changes explain diversity among reptiles and amphibians

DEFF Research Database (Denmark)

Bastos Araujo, Miguel; Nogués-Bravo, David; Diniz-Filho, Alexandre F.

2008-01-01

debated without reaching consensus. Here, we test the proposition that European species richness of reptiles and amphibians is driven by climate changes in the Quaternary. We find that climate stability between the Last Glacial Maximum (LGM) and the present day is a better predictor of species richness...

TEMPERATURE AND PRECIPITATION AS PREDICTORS OF SPECIES RICHNESS IN NORTHERN ANDEAN AMPHIBIANS FROM COLOMBIA

Directory of Open Access Journals (Sweden)

Ortiz-Yusty Carlos Eduardo

2013-07-01

Full Text Available Our objective was to explore the spatial distribution patterns of amphibian speciesrichness in Antioquia, as model for the tropical Andes, and determine how annualmean temperature, annual precipitation, and elevation range influence it. We alsobriefly compare local and global regression models for estimating the relationbetween environmental variables and species richness. Distribution maps for 223amphibian species and environmental variables were generalized onto grid mapsof 752 blocks each covering the entire Department of Antioquia. We explored therelationship between species richness and environment using two global regressionmodels (the Ordinary Least Squares “OLS” and Generalized Linear Squares“GLS” models and one local model (the Geographically Weighted Regression“GWR” model. We found a significant relationship between species richness andenvironmental variables (GLS r2: 0.869; GRW r2: 0.929. The GLS model efficientlyincorporated the spatial autocorrelation effect and handled spatial dependencein the regression error terms while the GWR model showed the best fit (r2 andbalance between number of parameters and fit (AICc. GWR parameters show widevariation within the study area, indicating that relationship between species richnessand climate is spatially complex. Temperature was the most important variablein the GLS and GWR models, and altitude range the least significant. The strongrelationship between environment and amphibian richness is possibly due to lifehistory traits of amphibians, such as ectothermy and water dependency to completethe life cycle

Transitions between sex-determining systems in reptiles and amphibians.

Science.gov (United States)

Sarre, Stephen D; Ezaz, Tariq; Georges, Arthur

2011-01-01

Important technological advances in genomics are driving a new understanding of the evolution of sex determination in vertebrates. In particular, comparative chromosome mapping in reptiles has shown an intriguing distribution of homology in sex chromosomes across reptile groups. When this new understanding is combined with the widespread distribution of genetic and temperature-dependent sex-determination mechanisms among reptiles, it is apparent that transitions between modes have occurred many times, as they have for amphibians (particularly between male and female heterogamety). It is also likely that thermosensitivity in sex determination is a key factor in those transitions in reptiles, and possibly in amphibians too. New models of sex determination involving temperature thresholds are providing the framework for the investigation of transitions and making possible key predictions about the homologies and sex-determination patterns expected among taxa in these groups. Molecular cytogenetics and other genomic approaches are essential to providing the fundamental material necessary to make advances in this field.

Population recovery following decline in an endangered stream-breeding frog (Mixophyes fleayi from subtropical Australia.

Directory of Open Access Journals (Sweden)

David Alan Newell

Full Text Available Amphibians have undergone dramatic declines and extinctions worldwide. Prominent among these have been the stream-breeding frogs in the rainforests of eastern Australia. The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd has been postulated as the primary cause of these declines. We conducted a capture-mark-recapture study over a 7-year period on the endangered Fleay's barred frog (Mixophyes fleayi at two independent streams (30 km apart in order to assess the stability of these populations. This species had undergone a severe decline across its narrow geographic range. Mark-recapture modelling showed that the number of individuals increased 3-10 fold along stream transects over this period. Frog detection probabilities were frequently above 50% but declined as the populations increased. Adult survival was important to overall population persistence in light of low recruitment events, suggesting that longevity may be a key factor in this recovery. One male and female were present in the capture record for >6 years. This study provides an unambiguous example of population recovery in the presence of Bd.

FACTORS IMPLICATED IN AMPHIBIAN POPULATION DECLINES IN THE UNITED STATES

Science.gov (United States)

This study identified the factors responsible for the decline of native amphibians in the U.S. The type of land use, the introduction of exotic animal species, and chemical contamination were identified as the most likely causes of decline.

Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus

DEFF Research Database (Denmark)

Gottschalk, Sanne; Gottlieb, Caroline Trebbien; Vestergaard, Martin

2015-01-01

antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around...... and at alkaline pH, while it was compromised by acidic pH and exposure to serum. Furthermore, at subinhibitory concentrations of FL9, S. aureus responded by increasing the expression of two major virulence factor genes, namely the regulatory rnaIII and hla, encoding α-haemolysin. In addition, the S. aureus...... the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl2 concentrations...

A checklist of the amphibians and reptiles of Honduras, with additions, comments on taxonomy, some recent taxonomic decisions, and areas of further studies needed.

Science.gov (United States)

Mccranie, James R

2015-03-13

An updated checklist of the amphibians and reptiles of Honduras is provided. The list includes three amphibian species (Ptychohyla euthysanota, Bolitoglossa odonnelli, Oedipina chortiorum) and two reptile species (Laemanctus waltersi [elevated from subspecies status], Epictia phenops) not included in the most recent checklist of the amphibians and reptiles of the country. Also, one amphibian genus and species (Triprion petasatus) is removed from the country list and one Honduran lizard (Ctenosaura praeocularis) is synonymized with an older name. Comments where more study is needed are also included where pertinent. Authors, dates, and original spellings of the higher-level taxonomy of all taxa covered herein are also given. A total of 401 species (137 amphibians and 264 reptiles) are now known from the country with 111 species (27.7%) being Honduran endemics (52 amphibians and 59 reptiles).

Effects of land-use change on community composition of tropical amphibians and reptiles in Sulawesi, Indonesia.

Science.gov (United States)

Wanger, Thomas C; Iskandar, Djoko T; Motzke, Iris; Brook, Barry W; Sodhi, Navjot S; Clough, Yann; Tscharntke, Teja

2010-06-01

Little is known about the effects of anthropogenic land-use change on the amphibians and reptiles of the biodiverse tropical forests of Southeast Asia. We studied a land-use modification gradient stretching from primary forest, secondary forest, natural-shade cacao agroforest, planted-shade cacao agroforest to open areas in central Sulawesi, Indonesia. We determined species richness, abundance, turnover, and community composition in all habitat types and related these to environmental correlates, such as canopy heterogeneity and thickness of leaf litter. Amphibian species richness decreased systematically along the land-use modification gradient, but reptile richness and abundance peaked in natural-shade cacao agroforests. Species richness and abundance patterns across the disturbance gradient were best explained by canopy cover and leaf-litter thickness in amphibians and by canopy heterogeneity and cover in reptiles. Amphibians were more severely affected by forest disturbance in Sulawesi than reptiles. Heterogeneous canopy cover and thick leaf litter should be maintained in cacao plantations to facilitate the conservation value for both groups. For long-term and sustainable use of plantations, pruned shade trees should be permanently kept to allow rejuvenation of cacao and, thus, to prevent repeated forest encroachment.

ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

Science.gov (United States)

Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

The montane forest associated amphibian species of the Taita Hills ...

African Journals Online (AJOL)

The montane forest associated amphibian species of the Taita Hills, Kenya. ... They are surrounded by the dry Tsavo plains. ... The biodiversity importance of the Taita Hills lies with the number of endemics per unit of area of remaining forest, ...

Amphibian embryo and parental defenses and a larval predator reduce egg mortality from water mold.

Science.gov (United States)

Gomez-Mestre, Ivan; Touchon, Justin C; Warkentin, Karen M

2006-10-01

Water molds attack aquatic eggs worldwide and have been associated with major mortality events in some cases, but typically only in association with additional stressors. We combined field observations and laboratory experiments to study egg stage defenses against pathogenic water mold in three temperate amphibians. Spotted salamanders (Ambystoma maculatum) wrap their eggs in a protective jelly layer that prevents mold from reaching the embryos. Wood frog (Rana sylvatica) egg masses have less jelly but are laid while ponds are still cold and mold growth is slow. American toad (Bufo americanus) eggs experience the highest infection levels. They are surrounded by thin jelly and are laid when ponds have warmed and mold grows rapidly. Eggs of all three species hatched early when infected, yielding smaller and less developed hatchlings. This response was strongest in B. americanus. Precocious hatching increased vulnerability of wood frog hatchlings to invertebrate predators. Finally, despite being potential toad hatchling predators, R. sylvatica tadpoles can have a positive effect on B. americanus eggs. They eat water mold off infected toad clutches, increasing their hatching success.

Sequestered Alkaloid Defenses in the Dendrobatid Poison Frog Oophaga pumilio Provide Variable Protection from Microbial Pathogens.

Science.gov (United States)

Hovey, Kyle J; Seiter, Emily M; Johnson, Erin E; Saporito, Ralph A

2018-03-01

Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in dendrobatid poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect these frogs. Herein, we examined how alkaloid defenses in the dendrobatid poison frog, Oophaga pumilio, affect growth of the known anuran pathogens Aeromonas hydrophila and Klebsiella pneumoniae. Frogs were collected from five locations throughout Costa Rica that are known to vary in their alkaloid profiles. Alkaloids were isolated from individual skins, and extracts were assayed against both pathogens. Microbe subcultures were inoculated with extracted alkaloids to create dose-response curves. Subsequent spectrophotometry and cell counting assays were used to assess growth inhibition. GC-MS was used to characterize and quantify alkaloids in frog extracts, and our results suggest that variation in alkaloid defenses lead to differences in inhibition of these pathogens. The present study provides the first evidence that alkaloid variation in a dendrobatid poison frog is associated with differences in inhibition of anuran pathogens, and offers further support that alkaloid defenses in poison frogs confer protection against both pathogens and predators.

Endoparasites in some Swedish Amphibians

DEFF Research Database (Denmark)

Cedhagen, Tomas

1988-01-01

A study was made of the endoparasites in specimens of Rana arvalis and R. temporaria collected on two occasions from a locality of southern Sweden. Some frogs were investigated directly after capture while other frogs were kept hibernating and the composition of the parasites as well...... as the behaviour of the parasites were studied after the termination of hibernation. Twelve species of parasites were found. Six of them, Polystoma integerrimum, Pleurogenes claviger (Trematoda), Rhabdias bufonis, Oswaldocruzia filiformis, Cosmocerca ornata and Oxysomatium brevicauda- tum (Nematoda), have...... not previously been reported from Sweden. The late Prof. O. Nybelin's unpublished records of parasites found in Swedish amphibians are also given....

Communal egg-laying in reptiles and amphibians: evolutionary patterns and hypotheses.