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Sample records for amphibian chytrid fungus

  1. The invasive chytrid fungus of amphibians paralyzes lymphocyte responses

    OpenAIRE

    Fites, J. Scott; Ramsey, Jeremy P.; Holden, Whitney M.; Collier, Sarah P.; Sutherland, Danica M.; Reinert, Laura K.; Gayek, A. Sophia; Dermody, Terence S.; Aune, Thomas M.; Oswald-Richter, Kyra; Rollins-Smith, Louise A.

    2013-01-01

    The chytrid fungus, Batrachochytrium dendrobatidis, causes chytridiomycosis and is a major contributor to global amphibian declines. Although amphibians have robust immune defenses, clearance of this pathogen is impaired. Because inhibition of host immunity is a common survival strategy of pathogenic fungi, we hypothesized that B. dendrobatidis evades clearance by inhibiting immune functions. We found that B. dendrobatidis cells and supernantants impaired lymphocyte proliferation and induced ...

  2. Presence of the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis in Native Amphibians Exported from Madagascar

    OpenAIRE

    Kolby, Jonathan E.

    2014-01-01

    The emerging infectious disease chytridiomycosis is driven by the spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd), a highly virulent pathogen threatening global amphibian biodiversity. Although pandemic in distribution, previous intensive field surveys have failed to detect Bd in Madagascar, a biodiversity hotspot home to hundreds of endemic amphibian species. Due to the presence of Bd in nearby continental Africa and the ecological crisis that can be expected followin...

  3. First evidence of amphibian chytrid fungus (Batrachochytrium dendrobatidis and ranavirus in Hong Kong amphibian trade.

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    Jonathan E Kolby

    Full Text Available The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd and cloacal (ranavirus swabs by quantitative PCR detected pathogen presence in 31/265 (11.7% and in 105/185 (56.8% of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong's trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment.

  4. Terrestrial Dispersal and Potential Environmental Transmission of the Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis)

    OpenAIRE

    Kolby, Jonathan E.; Sara D Ramirez; Berger, Lee; Richards-Hrdlicka, Kathryn L.; Jocque, Merlijn; Lee F Skerratt

    2015-01-01

    Dispersal and exposure to amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) is not confined to the aquatic habitat, but little is known about pathways that facilitate exposure to wild terrestrial amphibians that do not typically enter bodies of water. We explored the possible spread of Bd from an aquatic reservoir to terrestrial substrates by the emergence of recently metamorphosed infected amphibians and potential deposition of Bd-positive residue on riparian vegetation in Cusuco...

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

    OpenAIRE

    Kolby, Jonathan E.; Lee F Skerratt

    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 find...

  6. Presence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in native amphibians exported from Madagascar.

    Directory of Open Access Journals (Sweden)

    Jonathan E Kolby

    Full Text Available The emerging infectious disease chytridiomycosis is driven by the spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd, a highly virulent pathogen threatening global amphibian biodiversity. Although pandemic in distribution, previous intensive field surveys have failed to detect Bd in Madagascar, a biodiversity hotspot home to hundreds of endemic amphibian species. Due to the presence of Bd in nearby continental Africa and the ecological crisis that can be expected following establishment in Madagascar, enhanced surveillance is imperative. I sampled 565 amphibians commercially exported from Madagascar for the presence of Bd upon importation to the USA, both to assist early detection efforts and demonstrate the conservation potential of wildlife trade disease surveillance. Bd was detected in three animals via quantitative PCR: a single Heterixalus alboguttatus, Heterixalus betsileo, and Scaphiophryne spinosa. This is the first time Bd has been confirmed in amphibians from Madagascar and presents an urgent call to action. Our early identification of pathogen presence prior to widespread infection provides the necessary tools and encouragement to catalyze a swift, targeted response to isolate and eradicate Bd from Madagascar. If implemented before establishment occurs, an otherwise likely catastrophic decline in amphibian biodiversity may be prevented.

  7. The Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis, in Fully Aquatic Salamanders from Southeastern North America

    OpenAIRE

    Chatfield, Matthew W. H.; Moler, Paul; Richards-Zawacki, Corinne L.

    2012-01-01

    Little is known about the impact that the pathogenic amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), has on fully aquatic salamander species of the eastern United States. As a first step in determining the impacts of Bd on these species, we aimed to determine the prevalence of Bd in wild populations of fully aquatic salamanders in the genera Amphiuma, Necturus, Pseudobranchus, and Siren. We sampled a total of 98 salamanders, representing nine species from sites in Florida, Miss...

  8. 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.

  9. Terrestrial Dispersal and Potential Environmental Transmission of the Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis).

    Science.gov (United States)

    Kolby, Jonathan E; Ramirez, Sara D; Berger, Lee; Richards-Hrdlicka, Kathryn L; Jocque, Merlijn; Skerratt, Lee F

    2015-01-01

    Dispersal and exposure to amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) is not confined to the aquatic habitat, but little is known about pathways that facilitate exposure to wild terrestrial amphibians that do not typically enter bodies of water. We explored the possible spread of Bd from an aquatic reservoir to terrestrial substrates by the emergence of recently metamorphosed infected amphibians and potential deposition of Bd-positive residue on riparian vegetation in Cusuco National Park, Honduras (CNP). Amphibians and their respective leaf perches were both sampled for Bd presence and the pathogen was detected on 76.1% (35/46) of leaves where a Bd-positive frog had rested. Although the viability of Bd detected on these leaves cannot be discerned from our quantitative PCR results, the cool air temperature, closed canopy, and high humidity of this cloud forest environment in CNP is expected to encourage pathogen persistence. High prevalence of infection (88.5%) detected in the recently metamorphosed amphibians and frequent shedding of Bd-positive residue on foliage demonstrates a pathway of Bd dispersal between aquatic and terrestrial habitats. This pathway provides the opportunity for environmental transmission of Bd among and between amphibian species without direct physical contact or exposure to an aquatic habitat. PMID:25927835

  10. Terrestrial Dispersal and Potential Environmental Transmission of the Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis.

    Directory of Open Access Journals (Sweden)

    Jonathan E Kolby

    Full Text Available Dispersal and exposure to amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd is not confined to the aquatic habitat, but little is known about pathways that facilitate exposure to wild terrestrial amphibians that do not typically enter bodies of water. We explored the possible spread of Bd from an aquatic reservoir to terrestrial substrates by the emergence of recently metamorphosed infected amphibians and potential deposition of Bd-positive residue on riparian vegetation in Cusuco National Park, Honduras (CNP. Amphibians and their respective leaf perches were both sampled for Bd presence and the pathogen was detected on 76.1% (35/46 of leaves where a Bd-positive frog had rested. Although the viability of Bd detected on these leaves cannot be discerned from our quantitative PCR results, the cool air temperature, closed canopy, and high humidity of this cloud forest environment in CNP is expected to encourage pathogen persistence. High prevalence of infection (88.5% detected in the recently metamorphosed amphibians and frequent shedding of Bd-positive residue on foliage demonstrates a pathway of Bd dispersal between aquatic and terrestrial habitats. This pathway provides the opportunity for environmental transmission of Bd among and between amphibian species without direct physical contact or exposure to an aquatic habitat.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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. PMID:26465924

  13. Chytrid fungus infections in laboratory and introduced Xenopus laevis populations:assessing the risks for U.K. native amphibians

    OpenAIRE

    Tinsley, Richard C.; Coxhead, Peter George; Stott, Lucy C; Tinsley, Matthew C.; Piccinni, Maya Z.; Guille, Matthew J.

    2015-01-01

    The chytrid fungus Batrachochytrium dendrobatidis (Bd) is notorious amongst current conservation biology challenges, responsible for mass mortality and extinction of amphibian species. World trade in amphibians is implicated in global dissemination. Exports of South African Xenopus laevis have led to establishment of this invasive species on four continents. Bd naturally infects this host in Africa and now occurs in several introduced populations. However, no previous studies have investigate...

  14. First survey for the amphibian chytrid fungus Batrachochytrium dendrobatidis in Connecticut (USA) finds widespread prevalence.

    Science.gov (United States)

    Richards-Hrdlicka, Kathryn L; Richardson, Jonathan L; Mohabir, Leon

    2013-02-28

    The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) is an emerging infectious fungal pathogen of amphibians and is linked to global population declines. Until now, there has only been 1 survey for the fungus in the northeastern USA, which focused primarily on northern New England. We tested for Bd in a large number of samples (916 individuals from 116 sites) collected throughout the state of Connecticut, representing 18 native amphibian species. In addition, 239 preserved wood frog Lithobates sylvaticus tadpoles from throughout the state were screened for the fungus. Bd presence was assessed in both the fresh field swabs and the preserved samples using a sensitive quantitative PCR assay. Our contemporary survey found widespread Bd prevalence throughout Connecticut, occurring in 14 species and in 28% of all sampled animals. No preserved L. sylvaticus specimens tested positive for the fungus. Two common species, bullfrogs R. catesbeiana and green frogs R. clamitans had particularly high infection rates (0.21-0.39 and 0.33-0.42, respectively), and given their wide distribution throughout the state, we suggest they may serve as sentinels for Bd occurrence in this region. Further analyses found that several other factors increase the likelihood of infection, including life stage, host sex, and host family. Within sites, ponds with ranids, especially green frogs, increased the likelihood of Bd prevalence. By studying Bd in populations not facing mass declines, the results from this study are an important contribution to our understanding of how some amphibian species and populations remain infected yet exhibit no signs of chytridiomycosis even when Bd is widely distributed. PMID:23446966

  15. Transition of chytrid fungus infection from mouthparts to hind limbs during amphibian metamorphosis.

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    McMahon, Taegan A; Rohr, Jason R

    2015-03-01

    The chytrid fungus, Batrachochytrium dendrobatidis (Bd), is implicated in worldwide amphibian declines. Bd has been shown to qualitatively transition from the mouthparts of tadpoles to the hindlimbs during metamorphosis, but we lack evidence of consistency in the timing of this transition across amphibian species. We also do not have predictive functions for the abundance of Bd in mouthparts and limbs as tadpoles develop or for the relationship between keratin and Bd abundance. Hence, researchers presently have little guidance on where to sample developing amphibians to maximize Bd detection, which could affect the accuracy of prevalence and abundance estimates for this deadly pathogen. Here, we show consistency in the timing of the transition of Bd from mouthparts to hind limbs across two frog species (Osteopilus septentrionalis and Mixophyes fasciolatus). Keratin and Bd simultaneously declined from the mouthparts starting at approximately Gosner stage 40. However, keratin on the hindlimbs began to appear at approximately stage 38 but, on average, Bd was not detectable on the hindlimbs until approximately stage 40, suggesting a lag between keratin and Bd arrival. Predictive functions for the relationships between developmental stage and keratin and developmental stage and Bd for mouthparts and hind limbs are provided so that researchers can optimize sampling designs and minimize erroneous conclusions associated with missing Bd infections or misestimating Bd abundance. PMID:25384612

  16. 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.

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

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    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. PMID:25354647

  18. The amphibian chytrid fungus, Batrachochytrium dendrobatidis, in fully aquatic salamanders from Southeastern North America.

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    Matthew W H Chatfield

    Full Text Available Little is known about the impact that the pathogenic amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, has on fully aquatic salamander species of the eastern United States. As a first step in determining the impacts of Bd on these species, we aimed to determine the prevalence of Bd in wild populations of fully aquatic salamanders in the genera Amphiuma, Necturus, Pseudobranchus, and Siren. We sampled a total of 98 salamanders, representing nine species from sites in Florida, Mississippi, and Louisiana. Overall, infection prevalence was found to be 0.34, with significant differences among genera but no clear geographic pattern. We also found evidence for seasonal variation, but additional sampling throughout the year is needed to clarify this pattern. The high rate of infection discovered in this study is consistent with studies of other amphibians from the southeastern United States. Coupled with previously published data on life histories and population densities, the results presented here suggest that fully aquatic salamanders may be serving as important vectors of Bd and the interaction between these species and Bd warrants additional research.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. 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.

  2. Prevalence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) at Buenos Aires National Wildlife Refuge, Arizona, USA

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    Sigafus, Brent H.; Hossack, Blake R.; Muths, Erin L.; Schwalbe, Cecil R.

    2014-01-01

    Information on disease presence can be of use to natural resource managers, especially in areas supporting threatened and endangered species that occur coincidentally with species that are suspected vectors for disease. Ad hoc reports may be of limited utility (Muths et al. 2009), but a general sense of pathogen presence (or absence) can inform management directed at T&E species, especially in regions where disease is suspected to have caused population declines (Bradley et al. 2002). The Chiricahua Leopard Frog (Lithobates chiricahuensis), a species susceptible to infection by the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) (Bradley et al. 2002), and the non-native, invasive American Bullfrog (L. catesbeianus), a suspected vector for chytridiomycosis (Schloegel et al. 2012, Gervasi et al. 2013), both occur at Buenos Aires National Wildlife Refuge (BANWR) and surrounding lands in southern Arizona. Efforts to eradicate the bullfrog from BANWR began in 1997 (Suhre, 2010). Eradication from the southern portion of BANWR was successful by 2008 but the bullfrog remains present at the Arivaca Cienega and in areas immediately adjacent to the refuge (Fig. 1). Curtailing the re-invasion of the bullfrog into BANWR will require vigilance as to ensure the health of Chiricahua Leopard Frog populations.

  3. Amphibian chytrid fungus (Batrachochytrium dendrobatidis) in coastal and montane California, USA Anurans

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    Fellers, Gary M.; Cole, Rebecca A.; Reinitz, David M.; Kleeman, Patrick M.

    2011-01-01

    We found amphibian chytrid fungus (Bd = Batrachochytrium dendrobatidis) to be widespread within a coastalwatershed at Point Reyes National Seashore, California and within two high elevation watersheds at Yosemite NationalPark, California. Bd was associated with all six species that we sampled (Bufo boreas, B. canorus, Pseudacris regilla, Ranadraytonii, R. sierrae, and Lithobates catesbeianus). For those species sampled at 10 or more sites within a watershed, thepercentage of Bd-positive sites varied from a low of 20.7% for P. regilla at one Yosemite watershed to a high of 79.6% forP. regilla at the Olema watershed at Point Reyes. At Olema, the percent of Bd-positive water bodies declined each year ofour study (2005-2007). Because P. regilla was the only species found in all watersheds, we used that species to evaluatehabitat variables related to the sites where P. regilla was Bd-positive. At Olema, significant variables were year, length ofshoreline (perimeter), percentage cover of rooted vegetation, and water depth. At the two Yosemite watersheds, waterdepth, water temperature, and silt/mud were the most important covariates, though the importance of these three factorsdiffered between the two watersheds. The presence of Bd in species that are not declining suggests that some of theamphibians in our study were innately resistant to Bd, or had developed resistance after Bd became established.

  4. Widespread occurrence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in the southeastern USA

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    Rothermel, Betsie B.; Walls, Susan C.; Mitchell, Joseph C.; Dodd, C. Kenneth, Jr.; Irwin, Lisa K.; Green, David E.; Vazquez, Victoria M.; Petranka, James W.; Stevenson, Dirk J.

    2008-01-01

     From 1999 to 2006, we sampled >1200 amphibians for the fungal pathogen Batrachochytrium dendrobatidis(Bd) at 30 sites in the southeastern USA. Using histological techniques or PCR assays, we detected chytrid infection in 10 species of aquatic-breeding amphibians in 6 states. The prevalence of chytrid infection was 17.8% for samples of postmetamorphic amphibians examined using skin swab-PCR assays (n = 202 samples from 12 species at 4 sites). In this subset of samples, anurans had a much higher prevalence of infection than caudates (39.2% vs. 5.5%, respectively). Mean prevalence in ranid frogs was 40.7%. The only infected salamanders were Notophthalmus viridescens at 3 sites. We found infected amphibians from late winter through late spring and in 1 autumn sample. Although we encountered moribund or dead amphibians at 9 sites, most mortality events were not attributed to Bd. Chytridiomycosis was established as the probable cause of illness or death in fewer than 10 individuals. Our observations suggest a pattern of widespread and subclinical infections. However, because most of the sites in our study were visited only once, we cannot dismiss the possibility that chytridiomycosis is adversely affecting some populations. Furthermore, although there is no evidence of chytrid-associated declines in our region, the presence of this pathogen is cause for concern given global climate change and other stressors. Although presence-absence surveys may still be needed for some taxa, such as bufonids, we recommend that future researchers focus on potential population-level effects at sites where Bd is now known to occur.

  5. 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 encountered

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

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    Tracie A Seimon

    Full Text Available 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

  7. 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.

  8. Effects of Pesticide Mixtures on Host-Pathogen Dynamics of the Amphibian Chytrid Fungus

    Science.gov (United States)

    Buck, Julia C.; Hua, Jessica; Brogan, William R.; Dang, Trang D.; Urbina, Jenny; Bendis, Randall J.; Stoler, Aaron B.; Blaustein, Andrew R.; Relyea, Rick A.

    2015-01-01

    Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often co-occur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batrachochytrium dendrobatidis (Bd), a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas) from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan) or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D) or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs). Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load. This result

  9. Effects of Pesticide Mixtures on Host-Pathogen Dynamics of the Amphibian Chytrid Fungus.

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    Julia C Buck

    Full Text Available Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often co-occur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batrachochytrium dendrobatidis (Bd, a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs. Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load

  10. Genomic Correlates of Virulence Attenuation in the Deadly Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Refsnider, Jeanine M; Poorten, Thomas J; Langhammer, Penny F; Burrowes, Patricia A; Rosenblum, Erica Bree

    2015-11-01

    Emerging infectious diseasespose a significant threat to global health, but predicting disease outcomes for particular species can be complicated when pathogen virulence varies across space, time, or hosts. The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused worldwide declines in frog populations. Not only do Bd isolates from wild populations vary in virulence, but virulence shifts can occur over short timescales when Bd is maintained in the laboratory. We leveraged changes in Bd virulence over multiple generations of passage to better understand mechanisms of pathogen virulence. We conducted whole-genome resequencing of two samples of the same Bd isolate, differing only in passage history, to identify genomic processes associated with virulence attenuation. The isolate with shorter passage history (and greater virulence) had greater chromosome copy numbers than the isolate maintained in culture for longer, suggesting that virulence attenuation may be associated with loss of chromosome copies. Our results suggest that genomic processes proposed as mechanisms for rapid evolution in Bd are correlated with virulence attenuation in laboratory culture within a single lineage of Bd. Moreover, these genomic processes can occur over extremely short timescales. On a practical level, our results underscore the importance of immediately cryo-archiving new Bd isolates and using fresh isolates, rather than samples cultured in the laboratory for long periods, for laboratory infection experiments. Finally, when attempting to predict disease outcomes for this ecologically important pathogen, it is critical to consider existing variation in virulence among isolates and the potential for shifts in virulence over short timescales. PMID:26333840

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

    Science.gov (United States)

    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. PMID:25958806

  12. Elevation, temperature, and aquatic connectivity all influence the infection dynamics of the amphibian chytrid fungus in adult frogs.

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    Sarah J Sapsford

    Full Text Available Infectious diseases can cause population declines and even extinctions. The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, has caused population declines and extinctions in amphibians on most continents. In the tropics, research on the dynamics of this disease has focused on amphibian populations in mountainous areas. In most of these areas, high and low elevation sites are connected by an assemblage of streams that may transport the infectious stage of the pathogen from high to low elevations, and, also, this pathogen, which grows well at cool temperatures, may persist better in cooler water flowing from high elevations. Thus, the dynamics of disease at low elevation sites without aquatic connections to higher elevation sites, i.e., non-contiguous low elevation sites, may differ from dynamics at contiguous low elevation sites. We sampled adult common mistfrogs (Litoria rheocola at six sites of three types: two at high (> 400 m elevations, two at low elevations contiguous with high elevation streams, and two at low elevations non-contiguous with any high elevation site. Adults were swabbed for Bd diagnosis from June 2010 to June 2011 in each season, over a total of five sampling periods. The prevalence of Bd fluctuated seasonally and was highest in winter across all site types. Site type significantly affected seasonal patterns of prevalence of Bd. Prevalence remained well above zero throughout the year at the high elevation sites. Prevalence declined to lower levels in contiguous low sites, and reached near-zero at non-contiguous low sites. Patterns of air temperature fluctuation were very similar at both the low elevation site types, suggesting that differences in water connectivity to high sites may have affected the seasonal dynamics of Bd prevalence between contiguous and non-contiguous low elevation site types. Our results also suggest that reservoir hosts may be important in the persistence of disease at low elevations.

  13. Activities of Temporin Family Peptides against the Chytrid Fungus (Batrachochytrium dendrobatidis) Associated with Global Amphibian Declines

    OpenAIRE

    Rollins-Smith, Louise A.; Carey, Cynthia; Conlon, J. Michael; Reinert, Laura K.; Doersam, Jennifer K.; Bergman, Tomas; Silberring, Jerzy; Lankinen, Hilkka; Wade, David

    2003-01-01

    Temporin A and structurally related peptides produced in amphibian dermal granular glands and in wasp venom were tested for growth inhibition of Batrachochytrium dendrobatidis, a pathogen associated with global amphibian declines. Two natural amphibian temporins, a wasp temporin, and six synthetic analogs effectively inhibited growth. Differences in potency due to amino acid substitution suggest that ability to penetrate membranes and form an α-helical structure is important for their effecti...

  14. Populations of a susceptible amphibian species can grow despite the presence of a pathogenic chytrid fungus.

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    Ursina Tobler

    Full Text Available Disease can be an important driver of host population dynamics and epizootics can cause severe host population declines. Batrachochytrium dendrobatidis (Bd, the pathogen causing amphibian chytridiomycosis, may occur epizootically or enzootically and can harm amphibian populations in many ways. While effects of Bd epizootics are well documented, the effects of enzootic Bd have rarely been described. We used a state-space model that accounts for observation error to test whether population trends of a species highly susceptible to Bd, the midwife toad Alytes obstetricans, are negatively affected by the enzootic presence of the pathogen. Unexpectedly, Bd had no negative effect on population growth rates from 2002-2008. This suggests that negative effects of disease on individuals do not necessarily translate into negative effects at the population level. Populations of amphibian species that are susceptible to the emerging disease chytridiomycosis can persist despite the enzootic presence of the pathogen under current environmental conditions.

  15. Mapping the global emergence of Batrachochytrium dendrobatidis, the amphibian chytrid fungus.

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    Deanna H Olson

    Full Text Available The rapid worldwide emergence of the amphibian pathogen Batrachochytrium dendrobatidis (Bd is having a profound negative impact on biodiversity. However, global research efforts are fragmented and an overarching synthesis of global infection data is lacking. Here, we provide results from a community tool for the compilation of worldwide Bd presence and report on the analyses of data collated over a four-year period. Using this online database, we analysed: 1 spatial and taxonomic patterns of infection, including amphibian families that appear over- and under-infected; 2 relationships between Bd occurrence and declining amphibian species, including associations among Bd occurrence, species richness, and enigmatic population declines; and 3 patterns of environmental correlates with Bd, including climate metrics for all species combined and three families (Hylidae, Bufonidae, Ranidae separately, at both a global scale and regional (U.S.A. scale. These associations provide new insights for downscaled hypothesis testing. The pathogen has been detected in 52 of 82 countries in which sampling was reported, and it has been detected in 516 of 1240 (42% amphibian species. We show that detected Bd infections are related to amphibian biodiversity and locations experiencing rapid enigmatic declines, supporting the hypothesis that greater complexity of amphibian communities increases the likelihood of emergence of infection and transmission of Bd. Using a global model including all sampled species, the odds of Bd detection decreased with increasing temperature range at a site. Further consideration of temperature range, rather than maximum or minimum temperatures, may provide new insights into Bd-host ecology. Whereas caution is necessary when interpreting such a broad global dataset, the use of our pathogen database is helping to inform studies of the epidemiology of Bd, as well as enabling regional, national, and international prioritization of conservation

  16. Enhanced call effort in Japanese tree frogs infected by amphibian chytrid fungus.

    Science.gov (United States)

    An, Deuknam; Waldman, Bruce

    2016-03-01

    Some amphibians have evolved resistance to the devastating disease chytridiomycosis, associated with global population declines, but immune defences can be costly. We recorded advertisement calls of male Japanese tree frogs (Hyla japonica) in the field. We then assessed whether individuals were infected by Batrachochytrium dendrobatidis (Bd), the causal agent of the disease. This allowed us to analyse call properties of males as a function of their infection status. Infected males called more rapidly and produced longer calls than uninfected males. This enhanced call effort may reflect pathogen manipulation of host behaviour to foster disease transmission. Alternatively, increased calling may have resulted from selection on infected males to reproduce earlier because of their shortened expected lifespan. Our results raise the possibility that sublethal effects of Bd alter amphibian life histories, which contributes to long-term population declines. PMID:26932682

  17. Spatial Assessment of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) in South Africa Confirms Endemic and Widespread Infection

    OpenAIRE

    Tarrant, Jeanne; Cilliers, Dirk; du Preez, Louis H.; Weldon, Ché

    2013-01-01

    Chytridiomycosis has been identified as a major cause of global amphibian declines. Despite widespread evidence of Batrachochytrium dendrobatidis infection in South African frogs, sampling for this disease has not focused on threatened species, or whether this pathogen poses a disease risk to these species. This study assessed the occurrence of Bd-infection in South African Red List species. In addition, all known records of infection from South Africa were used to model the ecological niche ...

  18. Variation in Thermal Performance of a Widespread Pathogen, the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis

    OpenAIRE

    Stevenson, Lisa A.; Ross A. Alford; Bell, Sara C.; Elizabeth A Roznik; Berger, Lee; David A Pike

    2013-01-01

    Rates of growth and reproduction of the pathogens that cause emerging infectious diseases can be affected by local environmental conditions; these conditions can thus influence the strength and nature of disease outbreaks. An understanding of these relationships is important for understanding disease ecology and developing mitigation strategies. Widespread emergence of the fungal disease chytridiomycosis has had devastating effects on amphibian populations. The causative pathogen, Batrachochy...

  19. Amphibian pathogens at northern latitudes: presence of chytrid fungus and ranavirus in northeastern Canada.

    Science.gov (United States)

    D'Aoust-Messier, Andrée-Michelle; Echaubard, Pierre; Billy, Vincent; Lesbarrères, David

    2015-03-01

    Infections by the fungal pathogen Batrachochytrium dendrobatidis (Bd) and members of the genus Ranavirus (Rv) are increasingly reported as significant determinants of amphibian population die-offs. The complexity associated with their transmission and spatial distribution leads to an increase in demand for comprehensive reporting systems and global mapping of their distribution. Here, we document the distribution of these 2 pathogens in a remote northern temperate lowland where environmental sensitivity is high, providing important insight into the pathogens' natural history and infection patterns. Wood frog Lithobates sylvaticus tissues were collected from the James Bay area in northeastern Canada and were screened for the presence of Bd and Rv using conventional and real-time PCR. Both pathogens were present in the study area, which is the northernmost record in eastern North America. Interestingly, different patterns of distribution were observed between the eastern and western coasts of James Bay, suggesting differences in the spatial and transmission dynamics for each pathogen. Anthropogenic introduction may still influence the distribution patterns observed, even at these latitudes. The presence of infections in this remote area also raises further questions on the risk these pathogens pose to northern amphibian communities. We encourage further research in remote locations for a better understanding of these pathogens, their transmission dynamics, and especially their respective impacts on amphibian populations worldwide. PMID:25751857

  20. Spread of Amphibian Chytrid Fungus across Lowland Populations of Tungara Frogs in Panama.

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    Sofía Rodríguez-Brenes

    Full Text Available Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd, is an emergent infectious disease partially responsible for worldwide amphibian population declines. The spread of Bd along highland habitats (> 500 meters above sea level, m a.s.l. of Costa Rica and Panamá is well documented and has been linked to amphibian population collapses. In contrast, data are scarce on the prevalence and dispersal of Bd in lowland habitats where amphibians may be infected but asymptomatic. Here we describe the spread (2009 to 2014 of Bd across lowland habitats east of the Panamá Canal (< 500 m a.s.l. with a focus on the Túngara frog (Physalaemus [Engystomops] pustulosus, one of the most common and abundant frog species in this region. Highland populations in western Panamá were already infected with Bd at the start of the study, which was consistent with previous studies indicating that Bd is enzootic in this region. In central Panamá, we collected the first positive samples in 2010, and by 2014, we detected Bd from remote sites in eastern Panamá (Darién National Park. We discuss the importance of studying Bd in lowland species, which may serve as potential reservoirs and agents of dispersal of Bd to highland species that are more susceptible to chytridiomycosis.

  1. Spread of Amphibian Chytrid Fungus across Lowland Populations of Túngara Frogs in Panamá.

    Science.gov (United States)

    Rodríguez-Brenes, Sofía; Rodriguez, David; Ibáñez, Roberto; Ryan, Michael J

    2016-01-01

    Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emergent infectious disease partially responsible for worldwide amphibian population declines. The spread of Bd along highland habitats (> 500 meters above sea level, m a.s.l.) of Costa Rica and Panamá is well documented and has been linked to amphibian population collapses. In contrast, data are scarce on the prevalence and dispersal of Bd in lowland habitats where amphibians may be infected but asymptomatic. Here we describe the spread (2009 to 2014) of Bd across lowland habitats east of the Panamá Canal (< 500 m a.s.l.) with a focus on the Túngara frog (Physalaemus [Engystomops] pustulosus), one of the most common and abundant frog species in this region. Highland populations in western Panamá were already infected with Bd at the start of the study, which was consistent with previous studies indicating that Bd is enzootic in this region. In central Panamá, we collected the first positive samples in 2010, and by 2014, we detected Bd from remote sites in eastern Panamá (Darién National Park). We discuss the importance of studying Bd in lowland species, which may serve as potential reservoirs and agents of dispersal of Bd to highland species that are more susceptible to chytridiomycosis. PMID:27176629

  2. Spread of Amphibian Chytrid Fungus across Lowland Populations of Túngara Frogs in Panamá

    Science.gov (United States)

    Rodríguez-Brenes, Sofía; Rodriguez, David; Ibáñez, Roberto; Ryan, Michael J.

    2016-01-01

    Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emergent infectious disease partially responsible for worldwide amphibian population declines. The spread of Bd along highland habitats (> 500 meters above sea level, m a.s.l.) of Costa Rica and Panamá is well documented and has been linked to amphibian population collapses. In contrast, data are scarce on the prevalence and dispersal of Bd in lowland habitats where amphibians may be infected but asymptomatic. Here we describe the spread (2009 to 2014) of Bd across lowland habitats east of the Panamá Canal (< 500 m a.s.l.) with a focus on the Túngara frog (Physalaemus [Engystomops] pustulosus), one of the most common and abundant frog species in this region. Highland populations in western Panamá were already infected with Bd at the start of the study, which was consistent with previous studies indicating that Bd is enzootic in this region. In central Panamá, we collected the first positive samples in 2010, and by 2014, we detected Bd from remote sites in eastern Panamá (Darién National Park). We discuss the importance of studying Bd in lowland species, which may serve as potential reservoirs and agents of dispersal of Bd to highland species that are more susceptible to chytridiomycosis. PMID:27176629

  3. Physiological responses of Brazilian amphibians to an enzootic infection of the chytrid fungus Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Bovo, Rafael P; Andrade, Denis V; Toledo, Luís Felipe; Longo, Ana V; Rodriguez, David; Haddad, Célio F B; Zamudio, Kelly R; Becker, C Guilherme

    2016-01-13

    Pathophysiological effects of clinical chytridiomycosis in amphibians include disorders of cutaneous osmoregulation and disruption of the ability to rehydrate, which can lead to decreased host fitness or mortality. Less attention has been given to physiological responses of hosts where enzootic infections of Batrachochytrium dendrobatidis (Bd) do not cause apparent population declines in the wild. Here, we experimentally tested whether an enzootic strain of Bd causes significant mortality and alters host water balance (evaporative water loss, EWL; skin resistance, R(s); and water uptake, WU) in individuals of 3 Brazilian amphibian species (Dendropsophus minutus, n = 19; Ischnocnema parva, n = 17; Brachycephalus pitanga, n = 15). Infections with enzootic Bd caused no significant mortality, but we found an increase in R(s) in 1 host species concomitant with a reduction in EWL. These results suggest that enzootic Bd infections can indeed cause sub-lethal effects that could lead to reduction of host fitness in Brazilian frogs and that these effects vary among species. Thus, our findings underscore the need for further assessment of physiological responses to Bd infections in different host species, even in cases of sub-clinical chytridiomycosis and long-term enzootic infections in natural populations. PMID:26758658

  4. Spatial assessment of amphibian chytrid fungus (Batrachochytrium dendrobatidis in South Africa confirms endemic and widespread infection.

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    Jeanne Tarrant

    Full Text Available Chytridiomycosis has been identified as a major cause of global amphibian declines. Despite widespread evidence of Batrachochytrium dendrobatidis infection in South African frogs, sampling for this disease has not focused on threatened species, or whether this pathogen poses a disease risk to these species. This study assessed the occurrence of Bd-infection in South African Red List species. In addition, all known records of infection from South Africa were used to model the ecological niche of Bd to provide a better understanding of spatial patterns and associated disease risk. Presence and prevalence of Bd was determined through quantitative real-time PCR of 360 skin swab samples from 17 threatened species from 38 sites across the country. Average prevalence was 14.8% for threatened species, with pathogen load varying considerably between species. MaxEnt was used to model the predicted distribution of Bd based on 683 positive records for South Africa. The resultant probability threshold map indicated that Bd is largely restricted to the wet eastern and coastal regions of South Africa. A lack of observed adverse impacts on wild threatened populations supports the endemic pathogen hypothesis for southern Africa. However, all threatened species occur within the limits of the predicted distribution for Bd, exposing them to potential Bd-associated risk factors. Predicting pathogen distribution patterns and potential impact is increasingly important for prioritising research and guiding management decisions.

  5. Variation in thermal performance of a widespread pathogen, the amphibian chytrid fungus Batrachochytrium dendrobatidis.

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    Lisa A Stevenson

    Full Text Available Rates of growth and reproduction of the pathogens that cause emerging infectious diseases can be affected by local environmental conditions; these conditions can thus influence the strength and nature of disease outbreaks. An understanding of these relationships is important for understanding disease ecology and developing mitigation strategies. Widespread emergence of the fungal disease chytridiomycosis has had devastating effects on amphibian populations. The causative pathogen, Batrachochytriumdendrobatidis (Bd, is sensitive to temperature, but its thermal tolerances are not well studied. We examined the thermal responses of three Bd isolates collected across a latitudinal gradient in eastern Australia. Temperature affected all aspects of Bd growth and reproduction that we measured, in ways that often differed among Bd isolates. Aspects of growth, reproduction, and their relationships to temperature that differed among isolates included upper thermal maxima for growth (26, 27, or 28 °C, depending on the isolate, relationships between zoospore production and temperature, and zoospore activity and temperature. Two isolates decreased zoospore production as temperature increased, whereas the third isolate was less fecund overall, but did not show a strong response to temperature until reaching the upper limit of its thermal tolerance. Our results show differentiation in life-history traits among isolates within Australia, suggesting that the pathogen may exhibit local adaptation. An understanding of how environmental temperatures can limit pathogens by constraining fitness will enhance our ability to assess pathogen dynamics in the field, model pathogen spread, and conduct realistic experiments on host susceptibility and disease transmission.

  6. Short term minimum water temperatures determine levels of infection by the amphibian chytrid fungus in Alytes obstetricans tadpoles.

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    Saioa Fernández-Beaskoetxea

    Full Text Available Amphibians are one of the groups of wildlife most seriously threatened by emerging infectious disease. In particular, chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis, is responsible for amphibian species declines on a worldwide scale. Population-level outcomes following the introduction of the pathogen are context dependent and mediated by a large suite of abiotic and biotic variables. In particular, studies have shown that temperature has a key role in determining infection dynamics owing to the ectothermic nature of the amphibian host and temperature-dependency of pathogen growth rates. To assess the temperature-dependent seasonality of infectious burdens in a susceptible host species, we monitored lowland populations of larval midwife toads, Alytes obstetricians, in Central Spain throughout the year. We found that infections were highly seasonal, and inversely correlated against water temperature, with the highest burdens of infection seen during the colder months. Short-term impacts of water-temperature were found, with the minimum temperatures occurring before sampling being more highly predictive of infectious burdens than were longer-term spans of temperature. Our results will be useful for selecting the optimal time for disease surveys and, more broadly, for determining the key periods to undertake disease mitigation.

  7. 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.

  8. Community Structure and Function of Amphibian Skin Microbes: An Experiment with Bullfrogs Exposed to a Chytrid Fungus.

    Science.gov (United States)

    Walke, Jenifer B; Becker, Matthew H; Loftus, Stephen C; House, Leanna L; Teotonio, Thais L; Minbiole, Kevin P C; Belden, Lisa K

    2015-01-01

    The vertebrate microbiome contributes to disease resistance, but few experiments have examined the link between microbiome community structure and disease resistance functions. Chytridiomycosis, a major cause of amphibian population declines, is a skin disease caused by the fungus, Batrachochytrium dendrobatidis (Bd). In a factorial experiment, bullfrog skin microbiota was reduced with antibiotics, augmented with an anti-Bd bacterial isolate (Janthinobacterium lividum), or unmanipulated, and individuals were then either exposed or not exposed to Bd. We found that the microbial community structure of individual frogs prior to Bd exposure influenced Bd infection intensity one week following exposure, which, in turn, was negatively correlated with proportional growth during the experiment. Microbial community structure and function differed among unmanipulated, antibiotic-treated, and augmented frogs only when frogs were exposed to Bd. Bd is a selective force on microbial community structure and function, and beneficial states of microbial community structure may serve to limit the impacts of infection. PMID:26445500

  9. Community Structure and Function of Amphibian Skin Microbes: An Experiment with Bullfrogs Exposed to a Chytrid Fungus.

    Directory of Open Access Journals (Sweden)

    Jenifer B Walke

    Full Text Available The vertebrate microbiome contributes to disease resistance, but few experiments have examined the link between microbiome community structure and disease resistance functions. Chytridiomycosis, a major cause of amphibian population declines, is a skin disease caused by the fungus, Batrachochytrium dendrobatidis (Bd. In a factorial experiment, bullfrog skin microbiota was reduced with antibiotics, augmented with an anti-Bd bacterial isolate (Janthinobacterium lividum, or unmanipulated, and individuals were then either exposed or not exposed to Bd. We found that the microbial community structure of individual frogs prior to Bd exposure influenced Bd infection intensity one week following exposure, which, in turn, was negatively correlated with proportional growth during the experiment. Microbial community structure and function differed among unmanipulated, antibiotic-treated, and augmented frogs only when frogs were exposed to Bd. Bd is a selective force on microbial community structure and function, and beneficial states of microbial community structure may serve to limit the impacts of infection.

  10. Why Does Amphibian Chytrid (Batrachochytrium dendrobatidis) Not Occur Everywhere? An Exploratory Study in Missouri Ponds

    OpenAIRE

    Strauss, Alex; Smith, Kevin G.

    2013-01-01

    The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), is a globally emerging pathogen that has caused widespread amphibian population declines, extirpations, and extinctions. However, Bd does not occur in all apparently suitable amphibian populations, even within regions where it is widespread, and it is often unclear why Bd occurs in some habitats but not others. In this study, we rigorously surveyed the amphibian and invertebrate biodiversity of 29 ponds in Missouri, screened r...

  11. Chytrid fungus Batrachochytrium dendrobatidis has nonamphibian hosts and releases chemicals that cause pathology in the absence of infection

    OpenAIRE

    McMahon, Taegan A.; Laura A Brannelly; Chatfield, Matthew W. H.; Johnson, Pieter T. J.; Joseph, Maxwell B.; Valerie J McKenzie; Richards-Zawacki, Corinne L.; Venesky, Matthew D.; Rohr, Jason R.

    2012-01-01

    Batrachochytrium dendrobatidis, a pathogenic chytrid fungus implicated in worldwide amphibian declines, is considered an amphibian specialist. Identification of nonamphibian hosts could help explain the virulence, heterogeneous distribution, variable rates of spread, and persistence of B. dendrobatidis in freshwater ecosystems even after amphibian extirpations. Here, we test whether mosquitofish (Gambusia holbrooki) and crayfish (Procambarus spp. and Orconectes virilis), which are syntopic wi...

  12. Infection of an invasive frog Eleutherodactylus coqui by the chytrid fungus Batrachochytrium dendrobatidis in Hawaii

    OpenAIRE

    Beard, Karen H.; O'Neill, Eric M.

    2005-01-01

    The chytrid fungus Batrachochytrium dendrobatidis has contributed to declines and extinctions of amphibians worldwide. B. dendrobatidis is known to infect the frog Eleutherodactylus coqui in its native Puerto Rico. E. coqui was accidentally introduced into Hawaii in the late 1980s, where there are now hundreds of populations. B. dendrobatidis was being considered as a biological control agent for E. coqui because there are no native amphibians in Hawaii. Using a DNA-based assay, we tested 382...

  13. Elevated temperature clears chytrid fungus infections from tadpoles of the midwife toad, Alytes obstetricans

    OpenAIRE

    Geiger, C C; Küpfer, E; Schär, S; Wolf, S.; Schmidt, B R

    2011-01-01

    The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) is sensitive to high temperature. Hence, exposing amphibians to high temperature may be a method to clear Bd infection. However, the effect of exposure to elevated temperature has never been tested in larval stages or temperate species.We experimentally exposed tadpoles of the toad Alytes obstetricans to low, medium and high temperatures and found that most, but not all, tadpoles lost the infection when exposed to temperature...

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

    OpenAIRE

    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

    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 habi...

  15. West Africa – a safe haven for frogs? A sub–continental assessment of the Chytrid Fungus (Batrachochytrium dendrobatidis)

    OpenAIRE

    Penner, Johannes; Weldon, Ché; Adum, Gilbert B.; McElroy, Matthew T.; Doherty-Bone, Thomas

    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 - Be´nin, Burkina Faso, Coˆ te d’Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a var...

  16. Presence and significance of chytrid fungus Batrachochytrium dendrobatidis and other amphibian pathogens at warm-water fish hatcheries in southeastern North America

    Science.gov (United States)

    Green, D. Earl; Dodd, C. Kenneth, Jr.

    2007-01-01

    Amphibian populations and species are declining or disappearing from many regions throughout the world (Stuart et al. 2004). No single cause has been demonstrated, although a number of emerging infectious diseases have been suggested as primary etiologic agents (Berger et al. 1998; Daszak et al. 2003; Lips et al. 2006). Several factors, including climate change, parasite infestation or compromised immune systems may interact locally or regionally to threaten species and populations (Carey and Bryant 1995; Parris and Beaudoin 2004; Pounds et al. 2006). Still, the disease model of amphibian decline may not be universally applicable (Daszak et al. 2005; McCallum 2005).

  17. Why does Amphibian Chytrid (Batrachochytrium dendrobatidis not occur everywhere? An exploratory study in Missouri ponds.

    Directory of Open Access Journals (Sweden)

    Alex Strauss

    Full Text Available The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, is a globally emerging pathogen that has caused widespread amphibian population declines, extirpations, and extinctions. However, Bd does not occur in all apparently suitable amphibian populations, even within regions where it is widespread, and it is often unclear why Bd occurs in some habitats but not others. In this study, we rigorously surveyed the amphibian and invertebrate biodiversity of 29 ponds in Missouri, screened resident amphibian larvae (Rana (Lithobates sp. for Bd infection, and characterized the aquatic physiochemical environment of each pond (temperature pH, conductivity, nitrogen, phosphorus, and chlorophyll-a. Our goal was to generate hypotheses toward answering the question, "Why does Bd not occur in all apparently suitable habitats?" Bd occurred in assayed amphibians in 11 of the 29 ponds in our study area (38% of ponds. We found no significant relationship between any single biotic or abiotic variable and presence of Bd. However, multivariate analyses (nonmetric multidimensional scaling and permutational tests of dispersion revealed that ponds in which Bd occurred were a restricted subset of all ponds in terms of amphibian community structure, macroinvertebrate community structure, and pond physiochemistry. In other words, Bd ponds from 6 different conservation areas were more similar to each other than would be expected based on chance. The results of a structural equation model suggest that patterns in the occurrence of Bd among ponds are primarily attributable to variation in macroinvertebrate community structure. When combined with recent results showing that Bd can infect invertebrates as well as amphibians, we suggest that additional research should focus on the role played by non-amphibian biota in determining the presence, prevalence, and pathogenicity of Bd in amphibian populations.

  18. The Bacterially Produced Metabolite Violacein Is Associated with Survival of Amphibians Infected with a Lethal Fungus

    OpenAIRE

    Matthew H Becker; Brucker, Robert M.; Schwantes, Christian R.; Harris, Reid N.; Minbiole, Kevin P. C.

    2009-01-01

    The disease chytridiomycosis, which is caused by the chytrid fungus Batrachochytrium dendrobatidis, is associated with recent declines in amphibian populations. Susceptibility to this disease varies among amphibian populations and species, and resistance appears to be attributable in part to the presence of antifungal microbial species associated with the skin of amphibians. The betaproteobacterium Janthinobacterium lividum has been isolated from the skins of several amphibian species and pro...

  19. Immune Defenses against Batrachochytrium dendrobatidis, a Fungus Linked to Global Amphibian Declines, in the South African Clawed Frog, Xenopus laevis▿

    OpenAIRE

    Ramsey, Jeremy P.; Reinert, Laura K.; Harper, Laura K.; Douglas C Woodhams; Rollins-Smith, Louise A.

    2010-01-01

    Batrachochytrium dendrobatidis is a chytrid fungus that causes the lethal skin disease chytridiomycosis in amphibians. It is regarded as an emerging infectious disease affecting diverse amphibian populations in many parts of the world. Because there are few model amphibian species for immunological studies, little is known about immune defenses against B. dendrobatidis. We show here that the South African clawed frog, Xenopus laevis, is a suitable model for investigating immunity to this path...

  20. Dead or alive? Viability of chytrid zoospores shed from live amphibian hosts.

    Science.gov (United States)

    Maguire, Chelsea; DiRenzo, Graziella V; Tunstall, Tate S; Muletz, Carly R; Zamudio, Kelly R; Lips, Karen R

    2016-05-26

    Pathogens vary in virulence and rates of transmission because of many differences in the host, the pathogen, and their environment. The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), affects amphibian hosts differently, causing extinction and population declines in some species but having limited effects on others. Phenotypic differences in zoospore production rates among Bd lineages likely contribute to some of the variation observed among host responses, although no studies have quantified the viability of zoospores shed from live animals. We compared host survivorship, infection intensity, shedding rates, and zoospore viability between 2 species of endangered tropical frogs, Hylomantis lemur and Atelopus zeteki, when exposed to a highly virulent lineage of Bd (JEL 423). We applied a dye to zoospores 30 to 60 min following animal soaks, to estimate shedding rate and proportion of live zoospores shed by different species. The average infection intensity for A. zeteki was nearly 17 times higher (31,455 ± 10,103 zoospore genomic equivalents [ZGEs]) than that of H. lemur (1832 ± 1086 ZGEs), and A. zeteki died earlier than H. lemur. The proportion of viable zoospores was ~80% in both species throughout the experiment, although A. zeteki produced many more zoospores, suggesting it may play a disproportionate role in spreading disease in communities where it occurs, because the large number of viable zoospores they produce might increase infection in other species where they are reintroduced. PMID:27225201

  1. Chytrid fungus Batrachochytrium dendrobatidis has nonamphibian hosts and releases chemicals that cause pathology in the absence of infection.

    Science.gov (United States)

    McMahon, Taegan A; Brannelly, Laura A; Chatfield, Matthew W H; Johnson, Pieter T J; Joseph, Maxwell B; McKenzie, Valerie J; Richards-Zawacki, Corinne L; Venesky, Matthew D; Rohr, Jason R

    2013-01-01

    Batrachochytrium dendrobatidis, a pathogenic chytrid fungus implicated in worldwide amphibian declines, is considered an amphibian specialist. Identification of nonamphibian hosts could help explain the virulence, heterogeneous distribution, variable rates of spread, and persistence of B. dendrobatidis in freshwater ecosystems even after amphibian extirpations. Here, we test whether mosquitofish (Gambusia holbrooki) and crayfish (Procambarus spp. and Orconectes virilis), which are syntopic with many amphibian species, are possible hosts for B. dendrobatidis. Field surveys in Louisiana and Colorado revealed that zoosporangia occur within crayfish gastrointestinal tracts, that B. dendrobatidis prevalence in crayfish was up to 29%, and that crayfish presence in Colorado wetlands was a positive predictor of B. dendrobatidis infections in cooccurring amphibians. In experiments, crayfish, but not mosquitofish, became infected with B. dendrobatidis, maintained the infection for at least 12 wk, and transmitted B. dendrobatidis to amphibians. Exposure to water that previously held B. dendrobatidis also caused significant crayfish mortality and gill recession. These results indicate that there are nonamphibian hosts for B. dendrobatidis and suggest that B. dendrobatidis releases a chemical that can cause host pathology, even in the absence of infection. Managing these biological reservoirs for B. dendrobatidis and identifying this chemical might provide new hope for imperiled amphibians. PMID:23248288

  2. Joint effects of habitat, zooplankton, host stage structure and diversity on amphibian chytrid.

    Science.gov (United States)

    Hite, Jessica L; Bosch, Jaime; Fernández-Beaskoetxea, Saioa; Medina, Daniel; Hall, Spencer R

    2016-07-27

    Why does the severity of parasite infection differ dramatically across habitats? This question remains challenging to answer because multiple correlated pathways drive disease. Here, we examined habitat-disease links through direct effects on parasites and indirect effects on parasite predators (zooplankton), host diversity and key life stages of hosts. We used a case study of amphibian hosts and the chytrid fungus, Batrachochytrium dendrobatidis, in a set of permanent and ephemeral alpine ponds. A field experiment showed that ultraviolet radiation (UVR) killed the free-living infectious stage of the parasite. Yet, permanent ponds with more UVR exposure had higher infection prevalence. Two habitat-related indirect effects worked together to counteract parasite losses from UVR: (i) UVR reduced the density of parasite predators and (ii) permanent sites fostered multi-season host larvae that fuelled parasite production. Host diversity was unlinked to hydroperiod or UVR but counteracted parasite gains; sites with higher diversity of host species had lower prevalence of infection. Thus, while habitat structure explained considerable variation in infection prevalence through two indirect pathways, it could not account for everything. This study demonstrates the importance of creating mechanistic, food web-based links between multiple habitat dimensions and disease. PMID:27466456

  3. Waterfowl: potential environmental reservoirs of the chytrid fungus Batrachochytrium dendrobatidis

    OpenAIRE

    Garmyn, An; Van Rooij, Pascale; Pasmans, Frank; Hellebuyck, Tom; Van den Broeck, Wim; Haesebrouck, Freddy; Martel, An

    2012-01-01

    Infections with Batrachochytrium dendrobatidis (B. dendrobatidis), the causal agent of chytridiomycosis, have been shown to play an important role in the decline of amphibians worldwide. Spread of the fungus is poorly understood. Bird movement might possibly contribute to the spread of B. dendrobatidis in the environment. Therefore, 397 wild geese in Belgium were screened for presence of B. dendrobatidis on their toes using real-time quantitative PCR (qPCR). In addition, chemotaxis towards, a...

  4. Substrate-Specific Gene Expression in Batrachochytrium dendrobatidis, the Chytrid Pathogen of Amphibians

    OpenAIRE

    Rosenblum, Erica Bree; Poorten, Thomas J; Joneson, Suzanne; Settles, Matthew

    2012-01-01

    Determining the mechanisms of host-pathogen interaction is critical for understanding and mitigating infectious disease. Mechanisms of fungal pathogenicity are of particular interest given the recent outbreaks of fungal diseases in wildlife populations. Our study focuses on Batrachochytrium dendrobatidis (Bd), the chytrid pathogen responsible for amphibian declines around the world. Previous studies have hypothesized a role for several specific families of secreted proteases as pathogenicity ...

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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., III; Nanjappa, Priya; Olson, Deanna H.; Powers, Jenny G.; Richgels, Katherine L.D.; Russell, Robin E.; Schmidt, Benedikt R.; Spitzen-van der Sluijs, Annemarieka; Watry, Mary Kay; Woodhams, Douglas C.; White, C. LeAnn

    2016-01-01

    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

  7. Effects of temperature and hydric environment on survival of the Panamanian Golden Frog infected with a pathogenic chytrid fungus.

    Science.gov (United States)

    Bustamante, Heidi M; Livo, Lauren J; Carey, Cynthia

    2010-06-01

    Considerable controversy exists concerning whether or not climate changes (particularly global warming) are causing outbreaks of a lethal amphibian pathogen, the chytrid fungus Batrachochytrium dendrobatidis (Longcore, Pessier & D.K. Nichols 1999). In the present study, groups of Panamanian golden frogs (Atelopus zeteki Dunn, 1993), a critically endangered amphibian thought to be nearly extinct in Panama, were exposed to varying dosages of zoospores of Batrachochytrium dendrobatidis, temperatures and hydric environments in order to learn whether this species is susceptible to this pathogen and, if so, how environmental factors affect survival. This pathogen proved to be highly lethal for A. zeteki. Frogs exposed to a dosage of 100 Bd zoospores survived significantly (P<0.0001) longer than those that had been exposed to 10(4) or 10(6) zoospores. Exposed frogs housed at 23 °C survived significantly (P<0.0001) longer than those that were housed at 17 °C. Exposed frogs held in dry conditions survived significantly longer than those in wet conditions (P<0.0001). As a laboratory study, these results do not directly test hypotheses about the relation between climate change and the decline of these frogs in the field, but they inform the discussion about how environmental conditions can have an impact on the interaction between a susceptible amphibian and this pathogen. These data do not support the contention that rising global temperatures are necessary to cause the death of amphibians infected with this pathogen because the pathogen was equally lethal at 17 as at 23 °C, and frogs at the warmer temperature lived significantly longer than those at the cooler one. PMID:21392332

  8. Cell Density Effects of Frog Skin Bacteria on Their Capacity to Inhibit Growth of the Chytrid Fungus, Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Yasumiba, Kiyomi; Bell, Sara; Alford, Ross

    2016-01-01

    Bacterial symbionts on frog skin can reduce the growth of the chytrid fungus Batrachochytrium dendrobatidis (Bd) through production of inhibitory metabolites. Bacteria can be effective at increasing the resistance of amphibians to chytridiomycosis when added to amphibian skin, and isolates can be screened for production of metabolites that inhibit Bd growth in vitro. However, some bacteria use density-dependent mechanism such as quorum sensing to regulate metabolite production. It is therefore important to consider cell density effects when evaluating bacteria as possible candidates for bioaugmentation. The aim of our study was to evaluate how the density of cutaneous bacteria affects their inhibition of Bd growth in vitro. We sampled cutaneous bacteria isolated from three frog species in the tropical rainforests of northern Queensland, Australia, and selected ten isolates that were inhibitory to Bd in standardised pilot trials. We grew each isolate in liquid culture at a range of initial dilutions, sub-sampled each dilution at a series of times during the first 48 h of growth and measured spectrophotometric absorbance values, cell counts and Bd-inhibitory activity of cell-free supernatants at each time point. The challenge assay results clearly demonstrated that the inhibitory effects of most isolates were density dependent, with relatively low variation among isolates in the minimum cell density needed to inhibit Bd growth. We suggest the use of minimum cell densities and fast-growing candidate isolates to maximise bioaugmentation efforts. PMID:26563320

  9. The development of a spatially-explicit, individual-based, disease model for frogs and the chytrid fungus

    Science.gov (United States)

    Background / Question / Methods The fungal pathogen, Batrachochytrium dendrobatidis (BD), has been associated with amphibian population declines and even extinctions worldwide. Transmission of the fungus between amphibian hosts occurs via motile zoospores, which are produced on...

  10. Pathogenic Chytrid Fungus Batrachochytrium dendrobatidis, but Not B. salamandrivorans, Detected on Eastern Hellbenders

    OpenAIRE

    Bales, Emma K.; Oliver J Hyman; Loudon, Andrew H.; Harris, Reid N.; Lipps, Gregory; Chapman, Eric; Roblee, Kenneth; John D Kleopfer; Terrell, Kimberly A.

    2015-01-01

    Recent worldwide declines and extinctions of amphibian populations have been attributed to chytridiomycosis, a disease caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). Until recently, Bd was thought to be the only Batrachochytrium species that infects amphibians; however a newly described species, Batrachochytrium salamandrivorans (Bs), is linked to die-offs in European fire salamanders (Salamandra salamandra). Little is known about the distribution, host range, or origin ...

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Substrate-specific gene expression in Batrachochytrium dendrobatidis, the chytrid pathogen of amphibians.

    Directory of Open Access Journals (Sweden)

    Erica Bree Rosenblum

    Full Text Available Determining the mechanisms of host-pathogen interaction is critical for understanding and mitigating infectious disease. Mechanisms of fungal pathogenicity are of particular interest given the recent outbreaks of fungal diseases in wildlife populations. Our study focuses on Batrachochytrium dendrobatidis (Bd, the chytrid pathogen responsible for amphibian declines around the world. Previous studies have hypothesized a role for several specific families of secreted proteases as pathogenicity factors in Bd, but the expression of these genes has only been evaluated in laboratory growth conditions. Here we conduct a genome-wide study of Bd gene expression under two different nutrient conditions. We compare Bd gene expression profiles in standard laboratory growth media and in pulverized host tissue (i.e., frog skin. A large proportion of genes in the Bd genome show increased expression when grown in host tissue, indicating the importance of studying pathogens on host substrate. A number of gene classes show particularly high levels of expression in host tissue, including three families of secreted proteases (metallo-, serine- and aspartyl-proteases, adhesion genes, lipase-3 encoding genes, and a group of phylogenetically unusual crinkler-like effectors. We discuss the roles of these different genes as putative pathogenicity factors and discuss what they can teach us about Bd's metabolic targets, host invasion, and pathogenesis.

  13. Amphibian-killing chytrid in Brazil comprises both locally endemic and globally expanding populations.

    Science.gov (United States)

    Jenkinson, T S; Betancourt Román, C M; Lambertini, C; Valencia-Aguilar, A; Rodriguez, D; Nunes-de-Almeida, C H L; Ruggeri, J; Belasen, A M; da Silva Leite, D; Zamudio, K R; Longcore, J E; Toledo, F L; James, T Y

    2016-07-01

    Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is the emerging infectious disease implicated in recent population declines and extinctions of amphibian species worldwide. Bd strains from regions of disease-associated amphibian decline to date have all belonged to a single, hypervirulent clonal genotype (Bd-GPL). However, earlier studies in the Atlantic Forest of southeastern Brazil detected a novel, putatively enzootic lineage (Bd-Brazil), and indicated hybridization between Bd-GPL and Bd-Brazil. Here, we characterize the spatial distribution and population history of these sympatric lineages in the Brazilian Atlantic Forest. To investigate the genetic structure of Bd in this region, we collected and genotyped Bd strains along a 2400-km transect of the Atlantic Forest. Bd-Brazil genotypes were restricted to a narrow geographic range in the southern Atlantic Forest, while Bd-GPL strains were widespread and largely geographically unstructured. Bd population genetics in this region support the hypothesis that the recently discovered Brazilian lineage is enzootic in the Atlantic Forest of Brazil and that Bd-GPL is a more recently expanded invasive. We collected additional hybrid isolates that demonstrate the recurrence of hybridization between panzootic and enzootic lineages, thereby confirming the existence of a hybrid zone in the Serra da Graciosa mountain range of Paraná State. Our field observations suggest that Bd-GPL may be more infective towards native Brazilian amphibians, and potentially more effective at dispersing across a fragmented landscape. We also provide further evidence of pathogen translocations mediated by the Brazilian ranaculture industry with implications for regulations and policies on global amphibian trade. PMID:26939017

  14. The effects of a fungicide and chytrid fungus on anuran larvae in aquatic mesocosms.

    Science.gov (United States)

    Hanlon, Shane M; Lynch, Kyle J; Kerby, Jacob L; Parris, Matthew J

    2015-09-01

    The amphibian disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), has been linked to significant amphibian declines over the past three decades. The most severe effects of the pathogen have been primarily observed in relatively pristine areas that are not affected by many anthropogenic factors.One hypothesis concerning improved amphibian persistence with Bd in disturbed landscapes is that contaminants may abate the effects of Bd on amphibians. Recent laboratory studies have shown that pesticides, specifically the fungicide thiophanate-methyl (TM), can kill Bd outside of hosts and clear Bd infections within hosts. Using aquatic mesocosms, we tested the hypothesis that TM (0.43 mg/L) would alter growth and development of Lithobates sphenocephalus (southern leopard frog) tadpoles and Bd-infection loads in infected individuals. We hypothesized that the scope of such alterations and infection clearing would be affected by aquatic community variables, specifically zooplankton. TM altered zooplankton diversity (reduced cladoceran and increased copepod and ostracod abundances) and caused mortality to all tadpoles in TM-exposed tanks. In TM-free tanks, Bd-exposed tadpoles in high-density treatments metamorphosed smaller than Bd-unexposed, effects that were reversed in low-density treatments. Our study demonstrates the potential adverse effects of a fungicide and Bd on tadpoles and aquatic systems. PMID:25913318

  15. Coqui frogs persist with the deadly chytrid fungus despite a lack of defensive antimicrobial peptides.

    Science.gov (United States)

    Rollins-Smith, Louise A; Reinert, Laura K; Burrowes, Patricia A

    2015-02-10

    The amphibian skin fungus Batrachochytrium dendrobatidis (Bd) occurs widely in Puerto Rico and is thought to be responsible for the apparent extinction of 3 species of endemic frogs in the genus Eleutherodactylus, known as coquis. To examine immune defenses which may protect surviving species, we induced secretion of skin peptides from adult common coqui frogs E. coqui collected from upland forests at El Yunque. By matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, we were unable to detect peptide signals suggestive of antimicrobial peptides, and enriched peptides showed no capacity to inhibit growth of Bd. Thus, it appears that E. coqui depend on other skin defenses to survive in the presence of this deadly fungus. PMID:25667340

  16. Quantitative Proteomics of an Amphibian Pathogen, Batrachochytrium dendrobatidis, following Exposure to Thyroid Hormone

    OpenAIRE

    Thekkiniath, Jose; Zabet-Moghaddam, Masoud; Kottapalli, Kameswara Rao; Pasham, Mithun R.; San Francisco, Susan; San Francisco, Michael

    2015-01-01

    Batrachochytrium dendrobatidis (Bd), a chytrid fungus, has increasingly been implicated as a major factor in the worldwide decline of amphibian populations. The fungus causes chytridiomycosis in susceptible species leading to massive die-offs of adult amphibians. Although Bd infects the keratinized mouthparts of tadpoles and negatively affects foraging behavior, these infections are non-lethal. An important morphogen controlling amphibian metamorphosis is thyroid hormone (T3). Tadpoles may be...

  17. Prevalence of the pathogenic chytrid fungus, Batrachochytrium dendrobatidis, in an endangered population of northern leopard frogs, Rana pipiens

    OpenAIRE

    Govindarajulu Purnima; Houston Barb; Adama Doug; Voordouw Maarten J; Robinson John

    2010-01-01

    Abstract Background Emerging infectious diseases threaten naïve host populations with extinction. Chytridiomycosis, an emerging infectious disease of amphibians, is caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd) and has been linked to global declines in amphibians. Results We monitored the prevalence of Bd for four years in the Northern leopard frog, Rana pipiens, which is critically imperiled in British Columbia (BC), Canada. The prevalence of Bd initially increased and ...

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

    OpenAIRE

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

    2012-01-01

    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 inhibi...

  19. Pathogenic chytrid fungus Batrachochytrium dendrobatidis, but not B. salamandrivorans, detected on eastern hellbenders.

    Science.gov (United States)

    Bales, Emma K; Hyman, Oliver J; Loudon, Andrew H; Harris, Reid N; Lipps, Gregory; Chapman, Eric; Roblee, Kenneth; Kleopfer, John D; Terrell, Kimberly A

    2015-01-01

    Recent worldwide declines and extinctions of amphibian populations have been attributed to chytridiomycosis, a disease caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). Until recently, Bd was thought to be the only Batrachochytrium species that infects amphibians; however a newly described species, Batrachochytrium salamandrivorans (Bs), is linked to die-offs in European fire salamanders (Salamandra salamandra). Little is known about the distribution, host range, or origin of Bs. In this study, we surveyed populations of an aquatic salamander that is declining in the United States, the eastern hellbender (Cryptobranchus alleganiensis alleganiensis), for the presence of Bs and Bd. Skin swabs were collected from a total of 91 individuals in New York, Pennsylvania, Ohio, and Virginia, and tested for both pathogens using duplex qPCR. Bs was not detected in any samples, suggesting it was not present in these hellbender populations (0% prevalence, 95% confidence intervals of 0.0-0.04). Bd was found on 22 hellbenders (24% prevalence, 95% confidence intervals of 0.16 ≤ 0.24 ≤ 0.34), representing all four states. All positive samples had low loads of Bd zoospores (12.7 ± 4.9 S.E.M. genome equivalents) compared to other Bd susceptible species. More research is needed to determine the impact of Batrachochytrium infection on hellbender fitness and population viability. In particular, understanding how hellbenders limit Bd infection intensity in an aquatic environment may yield important insights for amphibian conservation. This study is among the first to evaluate the distribution of Bs in the United States, and is consistent with another, which failed to detect Bs in the U.S. Knowledge about the distribution, host-range, and origin of Bs may help control the spread of this pathogen, especially to regions of high salamander diversity, such as the eastern United States. PMID:25695636

  20. Pathogenic chytrid fungus Batrachochytrium dendrobatidis, but not B. salamandrivorans, detected on eastern hellbenders.

    Directory of Open Access Journals (Sweden)

    Emma K Bales

    Full Text Available Recent worldwide declines and extinctions of amphibian populations have been attributed to chytridiomycosis, a disease caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd. Until recently, Bd was thought to be the only Batrachochytrium species that infects amphibians; however a newly described species, Batrachochytrium salamandrivorans (Bs, is linked to die-offs in European fire salamanders (Salamandra salamandra. Little is known about the distribution, host range, or origin of Bs. In this study, we surveyed populations of an aquatic salamander that is declining in the United States, the eastern hellbender (Cryptobranchus alleganiensis alleganiensis, for the presence of Bs and Bd. Skin swabs were collected from a total of 91 individuals in New York, Pennsylvania, Ohio, and Virginia, and tested for both pathogens using duplex qPCR. Bs was not detected in any samples, suggesting it was not present in these hellbender populations (0% prevalence, 95% confidence intervals of 0.0-0.04. Bd was found on 22 hellbenders (24% prevalence, 95% confidence intervals of 0.16 ≤ 0.24 ≤ 0.34, representing all four states. All positive samples had low loads of Bd zoospores (12.7 ± 4.9 S.E.M. genome equivalents compared to other Bd susceptible species. More research is needed to determine the impact of Batrachochytrium infection on hellbender fitness and population viability. In particular, understanding how hellbenders limit Bd infection intensity in an aquatic environment may yield important insights for amphibian conservation. This study is among the first to evaluate the distribution of Bs in the United States, and is consistent with another, which failed to detect Bs in the U.S. Knowledge about the distribution, host-range, and origin of Bs may help control the spread of this pathogen, especially to regions of high salamander diversity, such as the eastern United States.

  1. Evidence for acquisition of virulence effectors in pathogenic chytrids

    Directory of Open Access Journals (Sweden)

    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.

  2. Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression

    OpenAIRE

    McMahon, Taegan A.; Brittany F Sears; Venesky, Matthew D.; Bessler, Scott M.; Brown, Jenise M.; Deutsch, Kaitlin; Halstead, Neal T.; Lentz, Garrett; Tenouri, Nadia; Young, Suzanne; Civitello, David J.; Ortega, Nicole; Fites, J. Scott; Reinert, Laura K.; Rollins-Smith, Louise A.

    2014-01-01

    Emerging fungal pathogens pose a greater threat to biodiversity than any other parasitic group1, causing declines of many taxa, including bats, corals, bees, snakes and amphibians1–4. Currently, there is little evidence that wild animals can acquire resistance to these pathogens5. Batrachochytrium dendrobatidis is a pathogenic fungus implicated in the recent global decline of amphibians6. Here we demonstrate that three species of amphibians can acquire behavioural or immunological resistance ...

  3. Batrachochytrium dendrobatidis infection of amphibians in the Doñana National Park, Spain

    OpenAIRE

    Hidalgo-Vila, J.; Díaz-Paniagua, Carmen; Marchand, Marc A.; Cunningham, Andrew A.

    2012-01-01

    Amphibian chytridiomycosis, caused by infection with the non-hyphal, zoosporic chytrid fungus Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease recognised as a cause of recent amphibian population declines and extinctions worldwide. The Doñana National Park (DNP) is located in southwestern Spain, a country with widespread Bd infection. This protected area has a great diversity of aquatic habitats that constitute important breeding habitats for 11 native amphibian species....

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

    Directory of Open Access Journals (Sweden)

    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

  5. The Amphibian Extinction Crisis - what will it take to put the action into the Amphibian Conservation Action Plan?

    OpenAIRE

    Bishop, P J; Angulo, A; Lewis, J P; Moore, R D; Rabb, G. B.; Moreno, J. Garcia

    2012-01-01

    The current mass extinction episode is most apparent in the amphibians. With approximately 7,000 species, amphibians are dependent on clean fresh water and damp habitats and are considered vulnerable to habitat loss (deforestation), changes in water or soil quality and the potential impacts of climate change, and in addition many species are suffering from an epidemic caused by a chytrid fungus. Because of their sensitivity and general dependence on both terrestrial and aquatic habitats they ...

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

    OpenAIRE

    Bletz, Molly C.; Rosa, Gonçalo M.; Andreone, Franco; Elodie A. Courtois; Schmeller, Dirk S; Nirhy H C Rabibisoa; 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 h...

  7. Prevalence of the pathogenic chytrid fungus, Batrachochytrium dendrobatidis, in an endangered population of northern leopard frogs, Rana pipiens

    Directory of Open Access Journals (Sweden)

    Govindarajulu Purnima

    2010-03-01

    Full Text Available Abstract Background Emerging infectious diseases threaten naïve host populations with extinction. Chytridiomycosis, an emerging infectious disease of amphibians, is caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd and has been linked to global declines in amphibians. Results We monitored the prevalence of Bd for four years in the Northern leopard frog, Rana pipiens, which is critically imperiled in British Columbia (BC, Canada. The prevalence of Bd initially increased and then remained constant over the last three years of the study. Young of the year emerging from breeding ponds in summer were rarely infected with Bd. Some individuals cleared their Bd infections and the return rate between infected and uninfected individuals was not significantly different. Conclusions The BC population of R. pipiens appears to have evolved a level of resistance that allows it to co-exist with Bd. However, this small population of R. pipiens remains vulnerable to extinction.

  8. First record of the chytrid fungus in Lithobates catesbeianus from Argentina: exotic species and conservation Primer registro del hongo quitridio en Lithobates catesbeianus de Argentina: especies exóticas y conservación

    Directory of Open Access Journals (Sweden)

    Romina Ghirardi

    2011-12-01

    Full Text Available Chytridiomycosis, a disease caused by the chytrid fungus Batrachochytrium dendrobatidis (B.d., is recognized as one of the major factors of amphibian decline. Global trade of amphibians has been identified as one of the causes of B.d. spread, involving hundreds of species world wide. In this work we detected the presence of B.d. through histological examination on 5 out of 9 analyzed specimens of bullfrogs (Lithobates catesbeianus from a farm in Santa Fe City (Argentina, deposited since 1993 in the herpetological collection of the Provincial Museum of Natural Sciences "Florentino Ameghino". Our finding represents the oldest record of B.d. for Argentina and the first case of the chytrid fungus infecting the exotic bullfrog in this country. We emphasize the importance of determining and monitoring the distribution and spread of B.d in Argentina, particularly in areas where feral bullfrog populations have already been identified.La quitridiomicosis, enfermedad emergente producida por el hongo Batrachochytrium dendrobatidis (B.d., es reconocida como uno de los factores causantes de la declinación de anfibios. El comercio mundial de anfibios ha sido señalado como una de las fuentes de dispersión de B.d. En este trabajo se detectó la presencia de B.d. en la especie exótica rana toro (Lithobates catesbeianus mediante cortes histológicos en 5 de 9 ejemplares provenientes de un criadero de la ciudad de Santa Fe (Argentina, depositados y conservados desde 1993 en la Colección Herpetológica del Museo Provincial de Ciencias Naturales "Florentino Ameghino". Este registro representa el hallazgo más antiguo de B.d. en Argentina y el primer caso de este hongo en la rana toro exótica en el país; por lo que enfatizamos la importancia de determinar y monitorear la distribución y dispersión de B.d., particularmente en los sitios donde ya se han detectado poblaciones silvestres de rana toro.

  9. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs

    OpenAIRE

    Richards-Zawacki, Corinne L.

    2009-01-01

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host–pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection i...

  10. A Fungal Pathogen of Amphibians, Batrachochytrium dendrobatidis, Attenuates in Pathogenicity with In Vitro Passages

    OpenAIRE

    Langhammer, Penny F.; Lips, Karen R.; Burrowes, Patricia A.; Tunstall, Tate; Crystal M Palmer; Collins, James P.

    2013-01-01

    Laboratory investigations into the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), have accelerated recently, given the pathogen’s role in causing the global decline and extinction of amphibians. Studies in which host animals were exposed to Bd have largely assumed that lab-maintained pathogen cultures retained the infective and pathogenic properties of wild isolates. Attenuated pathogenicity is common in artificially maintained cultures of other pathogenic fungi, but to date, ...

  11. Batrachochytrium dendrobatidis in amphibians of Cameroon, including first records for caecilians

    OpenAIRE

    Doherty-Bone, T.M.; Gonwouo, N.L.; Hirschfeld, M; Ohst, T.; C. Weldon

    2013-01-01

    Amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has been hypothesised to be an indigenous parasite of African amphibians. In Cameroon, however, previous surveys in one region (in the northwest) failed to detect this pathogen, despite the earliest African Bd having been recorded from a frog in eastern Cameroon, plus one recent record in the far southeast. To reconcile these contrasting results, we present survey data from 12 localities across 6 regions of Cameroon from anurans (n...

  12. Emerging infectious disease and the loss of biodiversity in a Neotropical amphibian community

    OpenAIRE

    Lips, Karen R.; Brem, Forrest; Brenes, Roberto; Reeve, John D.; Ross A. Alford; Voyles, Jamie; Carey, Cynthia; Livo, Lauren; Allan P Pessier; Collins, James P.

    2006-01-01

    Pathogens rarely cause extinctions of host species, and there are few examples of a pathogen changing species richness and diversity of an ecological community by causing local extinctions across a wide range of species. We report the link between the rapid appearance of a pathogenic chytrid fungus Batrachochytrium dendrobatidis in an amphibian community at El Copé, Panama, and subsequent mass mortality and loss of amphibian biodiversity across eight families of frogs and salamanders. We desc...

  13. Prevalence of the pathogenic chytrid fungus, Batrachochytrium dendrobatidis, in an endangered population of northern leopard frogs, Rana pipiens

    OpenAIRE

    Voordouw, Maarten J.; Adama, Doug; Houston, Barb; Govindarajulu, Purnima; Robinson, John

    2011-01-01

    Background Emerging infectious diseases threaten naïve host populations with extinction. Chytridiomycosis, an emerging infectious disease of amphibians, is caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd) and has been linked to global declines in amphibians. Results We monitored the prevalence of Bd for four years in the Northern leopard frog, Rana pipiens, which is critically imperiled in British Columbia (BC), Canada. The prevalence of Bd initially increased and then r...

  14. CITIZEN SCIENTISTS MONITOR A DEADLY FUNGUS THREATENING AMPHIBIAN COMMUNITIES IN NORTHERN COASTAL CALIFORNIA, USA.

    Science.gov (United States)

    Group, Ecoclub Amphibian; Pope, Karen L; Wengert, Greta M; Foley, Janet E; Ashton, Donald T; Botzler, Richard G

    2016-07-01

    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 2014. Using quantitative real-time PCR, 26 (17%) of 155 samples were positive for Bd. Positive samples occurred in four frog and toad species: foothill yellow-legged frog ( Rana boylii ), northern red-legged frog ( Rana aurora ), Pacific chorus frog ( Pseudacris regilla ), and western toad (Anaxyrus [Bufo] boreas); no salamanders or anuran larvae were positive. Except for R. aurora , all infected anurans were first-time species reports for coastal northern California. At the Refuge, significantly fewer (6/71) postmetamorphic amphibians were positive compared to the Parks (20/69; P=0.0018). We assessed the association of being PCR-positive for Bd, season of sampling, and age of sampler (child, teen, or adult). The full model with season, species, and sampler age had the greatest support. Frogs tested in winter or spring were more likely to be positive than those tested in summer or fall; foothill yellow-legged frogs, northern red-legged frogs, and western toads were more likely to be positive than were Pacific chorus frogs; and the probability of being positive nearly doubled when a child (≤12 yr old) collected the sample compared to a teen or adult. Our results support other chytrid studies that found amphibians are more susceptible to Bd when temperatures are cool and that species differ in their susceptibility. The Ecoclub's findings provide new information important to conservation of northern California's coastal amphibians and demonstrate the value of involving children in citizen science. PMID:27195681

  15. Widespread occurrence of the chytrid fungus batrachochytrium dendrobatidis on oregon spotted frogs (rana pretiosa)

    Science.gov (United States)

    Pearl, C.A.; Bowerman, J.; Adams, M.J.; Chelgren, N.D.

    2009-01-01

    The pathogen Batrachochytrium dendrobatidis (Bd) has been associated with amphibian declines in multiple continents, including western North America. We investigated Bd prevalence in Oregon spotted frog (Rana pretiosa), a species that has declined across its range in the Pacific Northwest. Polymerase chain reaction analysis of skin swabs indicated that Bd was prevalent within populations (420 of 617 juvenile and adults) and widespread among populations (36 of 36 sites) where we sampled R. pretiosa in Oregon and Washington. We rarely detected Bd in R. pretiosa larvae (2 of 72). Prevalence of Bd in postmetamorphic R. pretiosa was inversely related to frog size. We found support for an interactive effect of elevation and sampling date on Bd: prevalence of Bd generally increased with date, but this effect was more pronounced at lower elevations. We also found evidence that the body condition of juvenile R. pretiosa with Bd decreased after their first winter. Our data indicate that some Oregon spotted frog populations are currently persisting with relatively high Bd prevalence, but the risk posed by Bd is unknown. ?? 2010 International Association for Ecology and Health.

  16. Salamanders increase their feeding activity when infected with the pathogenic chytrid fungus Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Hess, Alexandra; McAllister, Caroline; DeMarchi, Joseph; Zidek, Makenzie; Murone, Julie; Venesky, Matthew D

    2015-10-27

    Immune function is a costly line of defense against parasitism. When infected with a parasite, hosts frequently lose mass due to these costs. However, some infected hosts (e.g. highly resistant individuals) can clear infections with seemingly little fitness losses, but few studies have tested how resistant hosts mitigate these costly immune defenses. We explored this topic using eastern red-backed salamanders Plethodon cinereus and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Bd is generally lethal for amphibians, and stereotypical symptoms of infection include loss in mass and deficits in feeding. However, individuals of P. cinereus can clear their Bd infections with seemingly few fitness costs. We conducted an experiment in which we repeatedly observed the feeding activity of Bd-infected and non-infected salamanders. We found that Bd-infected salamanders generally increased their feeding activity compared to non-infected salamanders. The fact that we did not observe any differences in mass change between the treatments suggests that increased feeding might help Bd-infected salamanders minimize the costs of an effective immune response. PMID:26503775

  17. Inhibition of Local Immune Responses by the Frog-Killing Fungus Batrachochytrium dendrobatidis

    OpenAIRE

    Fites, J. Scott; Reinert, Laura K.; Chappell, Timothy M.; Rollins-Smith, Louise A.

    2014-01-01

    Amphibians are suffering unprecedented global declines. A leading cause is the infectious disease chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis. Chytridiomycosis is a skin disease which disrupts transport of essential ions leading to death. Soluble factors produced by B. dendrobatidis impair amphibian and mammalian lymphocytes in vitro, but previous studies have not shown the effects of these inhibitory factors in vivo. To demonstrate in vivo inhibition of immun...

  18. The amphibian pathogen Batrachochytrium dendrobatidis detected in a community of stream and wetland amphibians

    Science.gov (United States)

    Grant, E.H.C.; Bailey, L.L.; Ware, J.L.; Duncan, K.C.

    2008-01-01

    The amphibian chytrid fungus Batrachochytrium dendrobatidis, responsible for the potentially fatal amphibian disease chytridiomycosis, is known to occur in a large and ever increasing number of amphibian populations around the world. However, sampling has been biased towards stream- and wetland-breeding anurans, with little attention paid to stream-associated salamanders. We sampled three frog and three salamander species in the Chesapeake and Ohio Canal National Historic Park, Maryland, by swabbing animals for PCR analysis to detect DNA of B. dendrobatidis. Using PCR, we detected B. dendrobatidis DNA in both stream and wetland amphibians, and report here the first occurrence of the pathogen in two species of stream-associated salamanders. Future research should focus on mechanisms within habitats that may affect persistence and dissemination of B. dendrobatidis among stream-associated salamanders.

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

    Science.gov (United States)

    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. PMID:27373706

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

    Science.gov (United States)

    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

  1. Global gene expression profiles for life stages of the deadly amphibian pathogen Batrachochytrium dendrobatidis

    OpenAIRE

    Rosenblum, Erica Bree; Stajich, Jason E.; Maddox, Nicole; Eisen, Michael B

    2008-01-01

    Amphibians around the world are being threatened by an emerging pathogen, the chytrid fungus Batrachochytrium dendrobatidis (Bd). Despite intensive ecological study in the decade since Bd was discovered, little is known about the mechanism by which Bd kills frogs. Here, we compare patterns of global gene expression in controlled laboratory conditions for the two phases of the life cycle of Bd: the free-living zoospore and the substrate-embedded sporangia. We find zoospores to be transcription...

  2. Co-Infection by Chytrid Fungus and Ranaviruses in Wild and Harvested Frogs in the Tropical Andes.

    Directory of Open Access Journals (Sweden)

    Robin W Warne

    Full Text Available While global amphibian declines are associated with the spread of Batrachochytrium dendrobatidis (Bd, undetected concurrent co-infection by other pathogens may be little recognized threats to amphibians. Emerging viruses in the genus Ranavirus (Rv also cause die-offs of amphibians and other ectotherms, but the extent of their distribution globally, or how co-infections with Bd impact amphibians are poorly understood. We provide the first report of Bd and Rv co-infection in South America, and the first report of Rv infections in the amphibian biodiversity hotspot of the Peruvian Andes, where Bd is associated with extinctions. Using these data, we tested the hypothesis that Bd or Rv parasites facilitate co-infection, as assessed by parasite abundance or infection intensity within individual adult frogs. Co-infection occurred in 30% of stream-dwelling frogs; 65% were infected by Bd and 40% by Rv. Among terrestrial, direct-developing Pristimantis frogs 40% were infected by Bd, 35% by Rv, and 20% co-infected. In Telmatobius frogs harvested for the live-trade 49% were co-infected, 92% were infected by Bd, and 53% by Rv. Median Bd and Rv loads were similar in both wild (Bd = 101.2 Ze, Rv = 102.3 viral copies and harvested frogs (Bd = 103.1 Ze, Rv = 102.7 viral copies. While neither parasite abundance nor infection intensity were associated with co-infection patterns in adults, these data did not include the most susceptible larval and metamorphic life stages. These findings suggest Rv distribution is global and that co-infection among these parasites may be common. These results raise conservation concerns, but greater testing is necessary to determine if parasite interactions increase amphibian vulnerability to secondary infections across differing life stages, and constitute a previously undetected threat to declining populations. Greater surveillance of parasite interactions may increase our capacity to contain and mitigate the impacts of these and

  3. Co-Infection by Chytrid Fungus and Ranaviruses in Wild and Harvested Frogs in the Tropical Andes.

    Science.gov (United States)

    Warne, Robin W; LaBumbard, Brandon; LaGrange, Seth; Vredenburg, Vance T; Catenazzi, Alessandro

    2016-01-01

    While global amphibian declines are associated with the spread of Batrachochytrium dendrobatidis (Bd), undetected concurrent co-infection by other pathogens may be little recognized threats to amphibians. Emerging viruses in the genus Ranavirus (Rv) also cause die-offs of amphibians and other ectotherms, but the extent of their distribution globally, or how co-infections with Bd impact amphibians are poorly understood. We provide the first report of Bd and Rv co-infection in South America, and the first report of Rv infections in the amphibian biodiversity hotspot of the Peruvian Andes, where Bd is associated with extinctions. Using these data, we tested the hypothesis that Bd or Rv parasites facilitate co-infection, as assessed by parasite abundance or infection intensity within individual adult frogs. Co-infection occurred in 30% of stream-dwelling frogs; 65% were infected by Bd and 40% by Rv. Among terrestrial, direct-developing Pristimantis frogs 40% were infected by Bd, 35% by Rv, and 20% co-infected. In Telmatobius frogs harvested for the live-trade 49% were co-infected, 92% were infected by Bd, and 53% by Rv. Median Bd and Rv loads were similar in both wild (Bd = 101.2 Ze, Rv = 102.3 viral copies) and harvested frogs (Bd = 103.1 Ze, Rv = 102.7 viral copies). While neither parasite abundance nor infection intensity were associated with co-infection patterns in adults, these data did not include the most susceptible larval and metamorphic life stages. These findings suggest Rv distribution is global and that co-infection among these parasites may be common. These results raise conservation concerns, but greater testing is necessary to determine if parasite interactions increase amphibian vulnerability to secondary infections across differing life stages, and constitute a previously undetected threat to declining populations. Greater surveillance of parasite interactions may increase our capacity to contain and mitigate the impacts of these and other wildlife

  4. Development of antimicrobial peptide defenses of southern leopard frogs, Rana sphenocephala, against the pathogenic chytrid fungus, Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Holden, Whitney M; Reinert, Laura K; Hanlon, Shane M; Parris, Matthew J; Rollins-Smith, Louise A

    2015-01-01

    Amphibian species face the growing threat of extinction due to the emerging fungal pathogen Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis. Antimicrobial peptides (AMPs) produced in granular glands of the skin are an important defense against this pathogen. Little is known about the ontogeny of AMP production or the impact of AMPs on potentially beneficial symbiotic skin bacteria. We show here that Rana (Lithobates) sphenocephala produces a mixture of four AMPs with activity against B. dendrobatidis, and we report the minimum inhibitory concentration (MIC) of synthesized replicates of these four AMPs tested against B. dendrobatidis. Using mass spectrometry and protein quantification assays, we observed that R. sphenocephala does not secrete a mature suite of AMPs until approximately 12 weeks post-metamorphosis, and geographically disparate populations produce a different suite of peptides. Use of norepinephrine to induce maximal secretion significantly reduced levels of culturable skin bacteria. PMID:25218643

  5. Cardiac adaptations of bullfrog tadpoles in response to chytrid infection.

    Science.gov (United States)

    Salla, Raquel Fernanda; Gamero, Fernando Urban; Ribeiro, Larissa Rodrigues; Rizzi, Gisele Miglioranza; Medico, Samuel Espinosa Dal; Rissoli, Rafael Zanelli; Vieira, Conrado Augusto; Silva-Zacarin, Elaine Cristina Mathias; Leite, Domingos Silva; Abdalla, Fábio Camargo; Toledo, Luis Felipe; Costa, Monica Jones

    2015-08-01

    The chytrid fungus Batrachochytrium dendrobatidis (Bd) can result in heart failure in Bd-susceptible species. Since Bd infection generally does not cause mortality in North American bullfrogs, the aim of this work was to verify whether this species presents any cardiac adaptation that could improve the tolerance to the fungus. Thus, we analyzed tadpoles' activity level, relative ventricular mass, ventricle morphology, in loco heart frequency, and in vitro cardiac function. The results indicate that infected animals present an increase in both ventricular relative mass and in myofibrils' incidence, which accompanied the increase in myocytes' diameter. Such morphological alterations enabled an increase in the in vitro twitch force that, in vivo, would result in elevation of the cardiac stroke volume. This response requires much less energy expenditure than an elevation in heart frequency, but still enables the heart to pump a higher volume of blood per minute (i.e., an increase in cardiac output). As a consequence, the energy saved in the regulation of the cardiac function of Bd-infected tadpoles can be employed in other homeostatic adjustments to avoid the lethal effect of the fungus. Whether other species present this ability, and to what extent, remains uncertain, but such possible interspecific variability might explain different mortality rates among different species of Bd-infected amphibians. PMID:26055358

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

    OpenAIRE

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

    2015-01-01

    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 susc...

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

    Science.gov (United States)

    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

  8. Effects of an Infectious Fungus, Batrachochytrium dendrobatidis, on Amphibian Predator-Prey Interactions

    OpenAIRE

    Han, Barbara A; Catherine L Searle; BLAUSTEIN, ANDREW R.

    2011-01-01

    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. dendro...

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

    Directory of Open Access Journals (Sweden)

    Barbara A Han

    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.

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

    Science.gov (United States)

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

    2015-01-01

    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. PMID:26607488

  11. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs.

    Science.gov (United States)

    Richards-Zawacki, Corinne L

    2010-02-22

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host-pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection in a wild population of Panamanian golden frogs (Atelopus zeteki). The timing of first detection of the fungus was consistent with that of a wave of epidemic infections spreading south and eastward through Central America. During the epidemic, many golden frogs modified their thermoregulatory behaviour, raising body temperatures above their normal set point. Odds of infection decreased with increasing body temperature, demonstrating that even slight environmental or behavioural changes have the potential to affect an individual's vulnerability to infection. The thermal dependency of the relationship between B. dendrobatidis and its amphibian hosts demonstrates how the progression of an epidemic can be influenced by complex interactions between host and pathogen phenotypes and the environments in which they are found. PMID:19864287

  12. Evidence of a salt refuge: chytrid infection loads are suppressed in hosts exposed to salt.

    Science.gov (United States)

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

    2015-03-01

    With the incidence of emerging infectious diseases on the rise, it is becoming increasingly important to identify refuge areas that protect hosts from pathogens and therefore prevent population declines. For the chytrid fungus Batrachochytrium dendrobatidis, temperature and humidity refuge areas for amphibian hosts exist but are difficult to manipulate. Other environmental features that may affect the outcome of infection include water quality, drying regimes, abundance of alternate hosts and isolation from other hosts. We identified relationships between water bodies with these features and infection levels in the free-living hosts inhabiting them. Where significant relationships were identified, we used a series of controlled experiments to test for causation. Infection loads were negatively correlated with the salt concentration of the aquatic habitat and the degree of water level fluctuation and positively correlated with fish abundance. However, only the relationship with salt was confirmed experimentally. Free-living hosts inhabiting water bodies with mean salinities of up to 3.5 ppt had lower infection loads than those exposed to less salt. The experiment confirmed that exposure to sodium chloride concentrations >2 ppt significantly reduced host infection loads compared to no exposure (0 ppt). These results suggest that the exposure of amphibians to salt concentrations found naturally in lentic habitats may be responsible for the persistence of some susceptible species in the presence of B. dendrobatidis. By manipulating the salinity of water bodies, it may be possible to create refuges for declining amphibians, thus allowing them to be reintroduced to their former ranges. PMID:25416999

  13. Susceptibility of amphibians to chytridiomycosis is associated with MHC class II conformation.

    Science.gov (United States)

    Bataille, Arnaud; Cashins, Scott D; Grogan, Laura; Skerratt, Lee F; Hunter, David; McFadden, Michael; Scheele, Benjamin; Brannelly, Laura A; Macris, Amy; Harlow, Peter S; Bell, Sara; Berger, Lee; Waldman, Bruce

    2015-04-22

    The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause precipitous population declines in its amphibian hosts. Responses of individuals to infection vary greatly with the capacity of their immune system to respond to the pathogen. We used a combination of comparative and experimental approaches to identify major histocompatibility complex class II (MHC-II) alleles encoding molecules that foster the survival of Bd-infected amphibians. We found that Bd-resistant amphibians across four continents share common amino acids in three binding pockets of the MHC-II antigen-binding groove. Moreover, strong signals of selection acting on these specific sites were evident among all species co-existing with the pathogen. In the laboratory, we experimentally inoculated Australian tree frogs with Bd to test how each binding pocket conformation influences disease resistance. Only the conformation of MHC-II pocket 9 of surviving subjects matched those of Bd-resistant species. This MHC-II conformation thus may determine amphibian resistance to Bd, although other MHC-II binding pockets also may contribute to resistance. Rescuing amphibian biodiversity will depend on our understanding of amphibian immune defence mechanisms against Bd. The identification of adaptive genetic markers for Bd resistance represents an important step forward towards that goal. PMID:25808889

  14. RANAVIRUS CAUSES MASS DIE-OFFS OF ALPINE AMPHIBIANS IN THE SOUTHWESTERN ALPS, FRANCE.

    Science.gov (United States)

    Miaud, Claude; Pozet, Françoise; Gaudin, Nadine Curt Grand; Martel, An; Pasmans, Frank; Labrut, Sophie

    2016-04-28

    Pathogenic fungi and viruses cause mortality outbreaks in wild amphibians worldwide. In the summer of 2012, dead tadpoles and adults of the European common frog Rana temporaria were reported in alpine lakes in the southwestern Alps (Mercantour National Park, France). A preliminary investigation using molecular diagnostic techniques identified a Ranavirus as the potential pathogenic agent. Three mortality events were recorded in the park, and samples were collected. The amphibian chytrid fungus Batrachochytrium dendrobatidis was not detected in any of the dead adult and juvenile frogs sampled (n=16) whereas all specimens were positive for a Ranavirus. The genome sequence of this Ranavirus was identical to previously published sequences of the common midwife toad virus (CMTV), a Ranavirus that has been associated with amphibian mortalities throughout Europe. We cultured virus from the organs of the dead common frogs and infecting adult male common frogs collected in another alpine region where no frog mortality had been observed. The experimentally infected frogs suffered 100% mortality (n=10). The alpine die-off is the first CMTV outbreak associated with mass mortality in wild amphibians in France. We describe the lesions observed and summarize amphibian populations affected by Ranaviruses in Europe. In addition, we discuss the ecologic specificities of mountain amphibians that may contribute to increasing their risk of exposure to and transmission of Ranaviruses. PMID:26967128

  15. No detection of chytrid in first systematic screening of Bombina variegata pachypus (Anura: Bombinatoridae in Liguria, northern Italy

    Directory of Open Access Journals (Sweden)

    Stefano Canessa

    2013-07-01

    Full Text Available The Apennine Yellow-bellied toad Bombina variegata pachypus, a small anuran endemic to peninsular Italy, has been declining throughout its range over the last 30 years. Although mortality by chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, was first reported for the species in 2004, its role in the decline has not yet been assessed. Between 2011 and 2012 we sampled eight populations of B. v. pachypus in Liguria, northern Italy, swabbing 86 and 143 individuals respectively, corresponding to between 24 and 80% of the estimated individuals within each population. We did not detect chytrid in any the samples collected. For the three largest populations in the region, we can rule out infections of prevalence greater than 10% with at least 98% confidence. Research at a larger scale is urgently needed to clarify the role of B. dendrobatidis in the decline of this and other amphibians in Italy.

  16. Absence of invasive Chytrid fungus (Batrachochytrium dendrobatidis in native Fijian ground frog (Platymantis vitiana populations on Viwa-Tailevu, Fiji Islands

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    Edward Narayan

    2011-12-01

    Full Text Available We report on the first survey of chytridiomycosis (Batrachochytrium dendrobatidis- Bd in the endangered Fijian ground frog (Platymantis vitiana population on Viwa-Tailevu, Fiji Islands. This fungal pathogen has been implicated as the primary cause of amphibian declines worldwide. Few cases have been reported from tropical Asia however it was recently documented in 4 species of frogs in Indonesia. Two hundred individual frogs were swabbed from 5 different sites on Viwa Island. Swabs were tested to quantify the number of Bd zoospore equivalents using real-time Polymerase Chain Reaction (qPCR technique. We found zero (% prevalence of Bd in ground frogs. The lack of Bd may be due to 1 hot weather all year round inhibiting the spread of Bd, 2 Bd may be absent from Viwa Island due to a lack of amphibian introductions (not introduced or importation of exotic frogs such as Rana catesbeia-na, or Xenopus spp or pet trade spp or 3 the lack of introduction by human vectors due to the geographic isolation, and low visitation of non-local people into the island. While it is difficult to test these hypotheses, a precautionary approach would suggest an effective quarantine is required to protect Fiji’s endemic frogs from future disease outbreak. Conservation effort and research is needed at international level to assist the Fiji government in monitoring and protecting their unique endemic amphibians from outbreaks of B. dendrobatidis.

  17. Current extinction rates of reptiles and amphibians.

    Science.gov (United States)

    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. PMID:26438855

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

    Science.gov (United States)

    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

  19. Effects of Biotic and Abiotic Setting on a Host-Pathogen Relationship: How Environmental and Community Characteristics Influence Infection Prevalence and Intensity of Amphibian Chytrid on California's Central Coast

    OpenAIRE

    Hemingway, Valentine

    2015-01-01

    In the face of swift anthropogenic change, it is essential to examine the broad ecological context for species of concern using a variety of approaches in order to understand their interactions in a natural context. Host-pathogen relationships offer a close interaction to examine how each are acted upon by biotic and abiotic conditions. Batrachochytrium dendrobatidis, an emerging infectious disease of amphibians, has been implicated with wholesale loss and marked declines in amphibian speci...

  20. Quantitative Proteomics of an Amphibian Pathogen, Batrachochytrium dendrobatidis, following Exposure to Thyroid Hormone.

    Directory of Open Access Journals (Sweden)

    Jose Thekkiniath

    Full Text Available Batrachochytrium dendrobatidis (Bd, a chytrid fungus, has increasingly been implicated as a major factor in the worldwide decline of amphibian populations. The fungus causes chytridiomycosis in susceptible species leading to massive die-offs of adult amphibians. Although Bd infects the keratinized mouthparts of tadpoles and negatively affects foraging behavior, these infections are non-lethal. An important morphogen controlling amphibian metamorphosis is thyroid hormone (T3. Tadpoles may be infected with Bd and the fungus may be exposed to T3 during metamorphosis. We hypothesize that exposure of Bd to T3 may induce the expression of factors associated with host colonization and pathogenicity. We utilized a proteomics approach to better understand the dynamics of the Bd-T3 interaction. Using liquid chromatography-mass spectrometry (LC-MS, we generated a data set of a large number of cytoplasmic and membrane proteins following exposure of Bd to T3. From these data, we identified a total of 263 proteins whose expression was significantly changed following T3 exposure. We provide evidence for expression of an array of proteins that may play key roles in both genomic and non-genomic actions of T3 in Bd. Additionally, our proteomics study shows an increase in several proteins including proteases and a class of uncommon crinkler and crinkler-like effector proteins suggesting their importance in Bd pathogenicity as well as those involved in metabolism and energy transfer, protein fate, transport and stress responses. This approach provides insights into the mechanistic basis of the Bd-amphibian interaction following T3 exposure.

  1. Amphibian immune defenses against chytridiomycosis: impacts of changing environments.

    Science.gov (United States)

    Rollins-Smith, Louise A; Ramsey, Jeremy P; Pask, James D; Reinert, Laura K; Woodhams, Douglas C

    2011-10-01

    Eco-immunology is the field of study that attempts to understand the functions of the immune system in the context of the host's environment. Amphibians are currently suffering devastating declines and extinctions in nearly all parts of the world due to the emerging infectious disease chytridiomycosis caused by the chytrid fungus, Batrachochytrium dendrobatidis. Because chytridiomycosis is a skin infection and remains confined to the skin, immune defenses of the skin are critical for survival. Skin defenses include secreted antimicrobial peptides and immunoglobulins as well as antifungal metabolites produced by symbiotic skin bacteria. Low temperatures, toxic chemicals, and stress inhibit the immune system and may impair natural defenses against B. dendrobatidis. Tadpoles' mouth parts can be infected by B. dendrobatidis. Damage to the mouth parts can impair growth, and the affected tadpoles maintain the pathogen in the environment even when adults have dispersed. Newly metamorphosing frogs appear to be especially vulnerable to infection and to the lethal effects of this pathogen because the immune system undergoes a dramatic reorganization at metamorphosis, and postmetamorphic defenses are not yet mature. Here we review our current understanding of amphibian immune defenses against B. dendrobatidis and the ability of the pathogen to resist those defenses. We also briefly review what is known about the impacts of temperature, environmental chemicals, and stress on the host-pathogen interactions and suggest future directions for research. PMID:21816807

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

    Science.gov (United States)

    Shin, Jaehyub; Bataille, Arnaud; Kosch, Tiffany A; Waldman, Bruce

    2014-01-01

    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. PMID:25333363

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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. PMID:27337484

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

    Science.gov (United States)

    Rohr, Jason R; Raffel, Thomas R

    2010-05-01

    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. PMID:20404180

  7. Long-term endemism of two highly divergent lineages of the amphibian-killing fungus in the Atlantic Forest of Brazil.

    Science.gov (United States)

    Rodriguez, D; Becker, C G; Pupin, N C; Haddad, C F B; Zamudio, K R

    2014-02-01

    The recent global spread of the amphibian-killing fungus [Batrachochytrium dendrobatidis (Bd)] has been closely tied to anthropogenic activities; however, regional patterns of spread are not completely understood. Using historical samples, we can test whether Bd was a spreading or endemic pathogen in a region within a particular time frame, because those two disease states provide different predictions for the regional demographic dynamics and population genetics of Bd. Testing historical patterns of pathogen prevalence and population genetics under these predictions is key to understanding the evolution and origin of Bd. Focusing on the Atlantic Forest (AF) of Brazil, we used qPCR assays to determine the presence or absence of Bd on 2799 preserved postmetamorphic anurans collected between 1894 and 2010 and used semi-nested PCRs to determine the frequency of rRNA ITS1 haplotypes from 52 samples. Our earliest date of detection was 1894. A mean prevalence of 23.9% over time and spatiotemporal patterns of Bd clusters indicate that Bd has been enzootic in the Brazilian AF with no evidence of regional spread within the last 116 years. ITS1 haplotypes confirm the long-term presence of two divergent strains of Bd (BdGPL and Bd-Brazil) and three spatiotemporally broad genetic demes within BdGPL, indicating that Bd was not introduced into southeast Brazil by the bullfrog trade. Our data show that the evolutionary history and pathogen dynamics of Bd in Brazil is better explained by the endemic pathogen hypothesis. PMID:24471406

  8. Fungal infection intensity and zoospore output of Atelopus zeteki, a potential acute chytrid supershedder.

    Directory of Open Access Journals (Sweden)

    Graziella V Direnzo

    Full Text Available Amphibians vary in their response to infection by the amphibian-killing chytrid fungus, Batrachochytrium dendrobatidis (Bd. Highly susceptible species are the first to decline and/or disappear once Bd arrives at a site. These competent hosts likely facilitate Bd proliferation because of ineffective innate and/or acquired immune defenses. We show that Atelopus zeteki, a highly susceptible species that has undergone substantial population declines throughout its range, rapidly and exponentially increases skin Bd infection intensity, achieving intensities that are several orders of magnitude greater than most other species reported. We experimentally infected individuals that were never exposed to Bd (n = 5 or previously exposed to an attenuated Bd strain (JEL427-P39; n = 3. Within seven days post-inoculation, the average Bd infection intensity was 18,213 zoospores (SE: 9,010; range: 0 to 66,928. Both average Bd infection intensity and zoospore output (i.e., the number of zoospores released per minute by an infected individual increased exponentially until time of death (t50 = 7.018, p<0.001, t46 = 3.164, p = 0.001, respectively. Mean Bd infection intensity and zoospore output at death were 4,334,422 zoospores (SE: 1,236,431 and 23.55 zoospores per minute (SE: 22.78, respectively, with as many as 9,584,158 zoospores on a single individual. The daily percent increases in Bd infection intensity and zoospore output were 35.4% (SE: 0.05 and 13.1% (SE: 0.04, respectively. We also found that Bd infection intensity and zoospore output were positively correlated (t43 = 3.926, p<0.001. All animals died between 22 and 33 days post-inoculation (mean: 28.88; SE: 1.58. Prior Bd infection had no effect on survival, Bd infection intensity, or zoospore output. We conclude that A. zeteki, a highly susceptible amphibian species, may be an acute supershedder. Our results can inform epidemiological models to estimate Bd outbreak probability, especially as they relate

  9. Fungal infection intensity and zoospore output of Atelopus zeteki, a potential acute chytrid supershedder.

    Science.gov (United States)

    Direnzo, Graziella V; Langhammer, Penny F; Zamudio, Kelly R; Lips, Karen R

    2014-01-01

    Amphibians vary in their response to infection by the amphibian-killing chytrid fungus, Batrachochytrium dendrobatidis (Bd). Highly susceptible species are the first to decline and/or disappear once Bd arrives at a site. These competent hosts likely facilitate Bd proliferation because of ineffective innate and/or acquired immune defenses. We show that Atelopus zeteki, a highly susceptible species that has undergone substantial population declines throughout its range, rapidly and exponentially increases skin Bd infection intensity, achieving intensities that are several orders of magnitude greater than most other species reported. We experimentally infected individuals that were never exposed to Bd (n = 5) or previously exposed to an attenuated Bd strain (JEL427-P39; n = 3). Within seven days post-inoculation, the average Bd infection intensity was 18,213 zoospores (SE: 9,010; range: 0 to 66,928). Both average Bd infection intensity and zoospore output (i.e., the number of zoospores released per minute by an infected individual) increased exponentially until time of death (t50 = 7.018, p<0.001, t46 = 3.164, p = 0.001, respectively). Mean Bd infection intensity and zoospore output at death were 4,334,422 zoospores (SE: 1,236,431) and 23.55 zoospores per minute (SE: 22.78), respectively, with as many as 9,584,158 zoospores on a single individual. The daily percent increases in Bd infection intensity and zoospore output were 35.4% (SE: 0.05) and 13.1% (SE: 0.04), respectively. We also found that Bd infection intensity and zoospore output were positively correlated (t43 = 3.926, p<0.001). All animals died between 22 and 33 days post-inoculation (mean: 28.88; SE: 1.58). Prior Bd infection had no effect on survival, Bd infection intensity, or zoospore output. We conclude that A. zeteki, a highly susceptible amphibian species, may be an acute supershedder. Our results can inform epidemiological models to estimate Bd outbreak probability, especially as they relate to

  10. Trophic dynamics in an aquatic community: interactions among primary producers, grazers, and a pathogenic fungus.

    Science.gov (United States)

    Buck, Julia C; Scholz, Katharina I; Rohr, Jason R; Blaustein, Andrew R

    2015-05-01

    Free-living stages of parasites are consumed by a variety of predators, which might have important consequences for predators, parasites, and hosts. For example, zooplankton prey on the infectious stage of the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), a pathogen responsible for amphibian population declines and extinctions worldwide. Predation on parasites is predicted to influence community structure and function, and affect disease risk, but relatively few studies have explored its consequences empirically. We investigated interactions among Rana cascadae tadpoles, zooplankton, and Bd in a fully factorial experiment in outdoor mesocosms. We measured growth, development, survival, and infection of amphibians and took weekly measurements of the abundance of zooplankton, phytoplankton (suspended algae), and periphyton (attached algae). We hypothesized that zooplankton might have positive indirect effects on tadpoles by consuming Bd zoospores and by consuming phytoplankton, thus reducing the shading of a major tadpole resource, periphyton. We also hypothesized that zooplankton would have negative effects on tadpoles, mediated by competition for algal resources. Mixed-effects models, repeated-measures ANOVAs, and a structural equation model revealed that zooplankton significantly reduced phytoplankton but had no detectable effects on Bd or periphyton. Hence, the indirect positive effects of zooplankton on tadpoles were negligible when compared to the indirect negative effect mediated by competition for phytoplankton. We conclude that examination of host-pathogen dynamics within a community context may be necessary to elucidate complex community dynamics. PMID:25432573

  11. Immunomodulatory metabolites released by the frog-killing fungus Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Rollins-Smith, Louise A; Fites, J Scott; Reinert, Laura K; Shiakolas, Andrea R; Umile, Thomas P; Minbiole, Kevin P C

    2015-12-01

    Batrachochytrium dendrobatidis is a fungal pathogen in the phylum Chytridiomycota that causes the skin disease chytridiomycosis. Chytridiomycosis is considered an emerging infectious disease linked to worldwide amphibian declines and extinctions. Although amphibians have well-developed immune defenses, clearance of this pathogen from the skin is often impaired. Previously, we showed that the adaptive immune system is involved in the control of the pathogen, but B. dendrobatidis releases factors that inhibit in vitro and in vivo lymphocyte responses and induce lymphocyte apoptosis. Little is known about the nature of the inhibitory factors released by this fungus. Here, we describe the isolation and characterization of three fungal metabolites produced by B. dendrobatidis but not by the closely related nonpathogenic chytrid Homolaphlyctis polyrhiza. These metabolites are methylthioadenosine (MTA), tryptophan, and an oxidized product of tryptophan, kynurenine (Kyn). Independently, both MTA and Kyn inhibit the survival and proliferation of amphibian lymphocytes and the Jurkat human T cell leukemia cell line. However, working together, they become effective at much lower concentrations. We hypothesize that B. dendrobatidis can adapt its metabolism to release products that alter the local environment in the skin to inhibit immunity and enhance the survival of the pathogen. PMID:26371122

  12. A fungal pathogen of amphibians, Batrachochytrium dendrobatidis, attenuates in pathogenicity with in vitro passages.

    Directory of Open Access Journals (Sweden)

    Penny F Langhammer

    Full Text Available Laboratory investigations into the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, have accelerated recently, given the pathogen's role in causing the global decline and extinction of amphibians. Studies in which host animals were exposed to Bd have largely assumed that lab-maintained pathogen cultures retained the infective and pathogenic properties of wild isolates. Attenuated pathogenicity is common in artificially maintained cultures of other pathogenic fungi, but to date, it is unknown whether, and to what degree, Bd might change in culture. We compared zoospore production over time in two samples of a single Bd isolate having different passage histories: one maintained in artificial media for more than six years (JEL427-P39, and one recently thawed from cryopreserved stock (JEL427-P9. In a common garden experiment, we then exposed two different amphibian species, Eleutherodactylus coqui and Atelopus zeteki, to both cultures to test whether Bd attenuates in pathogenicity with in vitro passages. The culture with the shorter passage history, JEL427-P9, had significantly greater zoospore densities over time compared to JEL427-P39. This difference in zoospore production was associated with a difference in pathogenicity for a susceptible amphibian species, indicating that fecundity may be an important virulence factor for Bd. In the 130-day experiment, Atelopus zeteki frogs exposed to the JEL427-P9 culture experienced higher average infection intensity and 100% mortality, compared with 60% mortality for frogs exposed to JEL427-P39. This effect was not observed with Eleutherodactylus coqui, which was able to clear infection. We hypothesize that the differences in phenotypic performance observed with Atelopus zeteki are rooted in changes of the Bd genome. Future investigations enabled by this study will focus on the underlying mechanisms of Bd pathogenicity.

  13. A fungal pathogen of amphibians, Batrachochytrium dendrobatidis, attenuates in pathogenicity with in vitro passages.

    Science.gov (United States)

    Langhammer, Penny F; Lips, Karen R; Burrowes, Patricia A; Tunstall, Tate; Palmer, Crystal M; Collins, James P

    2013-01-01

    Laboratory investigations into the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), have accelerated recently, given the pathogen's role in causing the global decline and extinction of amphibians. Studies in which host animals were exposed to Bd have largely assumed that lab-maintained pathogen cultures retained the infective and pathogenic properties of wild isolates. Attenuated pathogenicity is common in artificially maintained cultures of other pathogenic fungi, but to date, it is unknown whether, and to what degree, Bd might change in culture. We compared zoospore production over time in two samples of a single Bd isolate having different passage histories: one maintained in artificial media for more than six years (JEL427-P39), and one recently thawed from cryopreserved stock (JEL427-P9). In a common garden experiment, we then exposed two different amphibian species, Eleutherodactylus coqui and Atelopus zeteki, to both cultures to test whether Bd attenuates in pathogenicity with in vitro passages. The culture with the shorter passage history, JEL427-P9, had significantly greater zoospore densities over time compared to JEL427-P39. This difference in zoospore production was associated with a difference in pathogenicity for a susceptible amphibian species, indicating that fecundity may be an important virulence factor for Bd. In the 130-day experiment, Atelopus zeteki frogs exposed to the JEL427-P9 culture experienced higher average infection intensity and 100% mortality, compared with 60% mortality for frogs exposed to JEL427-P39. This effect was not observed with Eleutherodactylus coqui, which was able to clear infection. We hypothesize that the differences in phenotypic performance observed with Atelopus zeteki are rooted in changes of the Bd genome. Future investigations enabled by this study will focus on the underlying mechanisms of Bd pathogenicity. PMID:24130895

  14. Variation in the Presence of Anti-Batrachochytrium dendrobatidis Bacteria of Amphibians Across Life Stages and Elevations in Ecuador.

    Science.gov (United States)

    Bresciano, J C; Salvador, C A; Paz-Y-Miño, C; Parody-Merino, A M; Bosch, J; Woodhams, D C

    2015-06-01

    Amphibian populations are decreasing worldwide due to a variety of factors. In South America, the chytrid fungus Batrachochytrium dendrobatidis (Bd) is linked to many population declines. The pathogenic effect of Bd on amphibians can be inhibited by specific bacteria present on host skin. This symbiotic association allows some amphibians to resist the development of the disease chytridiomycosis. Here, we aimed (1) to determine for the first time if specific anti-Bd bacteria are present on amphibians in the Andes of Ecuador, (2) to monitor anti-Bd bacteria across developmental stages in a focal amphibian, the Andean marsupial tree frog, Gastrotheca riobambae, that deposits larvae in aquatic habitats, and (3) to compare the Bd presence associated with host assemblages including 10 species at sites ranging in biogeography from Amazonian rainforest (450 masl) to Andes montane rainforest (3200 masl). We sampled and identified skin-associated bacteria of frogs in the field using swabs and a novel methodology of aerobic counting plates, and a combination of morphological, biochemical, and molecular identification techniques. The following anti-Bd bacteria were identified and found to be shared among several hosts at high-elevation sites where Bd was present at a prevalence of 32.5%: Janthinobacterium lividum, Pseudomonas fluorescens, and Serratia sp. Bd were detected in Gastrotheca spp. and not detected in the lowlands (sites below 1000 masl). In G. riobambae, recognized Bd-resistant bacteria start to be present at the metamorphic stage. Overall bacterial abundance was significantly higher post-metamorphosis and on species sampled at lower elevations. Further metagenomic studies are needed to evaluate the roles of host identity, life-history stage, and biogeography of the microbiota and their function in disease resistance. PMID:25669915

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

    Science.gov (United States)

    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

  16. Absence of invasive Chytrid fungus (Batrachochytrium dendrobatidis) in native Fijian ground frog (Platymantis vitiana) populations on Viwa-Tailevu, Fiji Islands

    OpenAIRE

    Edward Narayan; Frank Molinia; Jean-Marc Hero

    2011-01-01

    We report on the first survey of chytridiomycosis (Batrachochytrium dendrobatidis- Bd) in the endangered Fijian ground frog (Platymantis vitiana) population on Viwa-Tailevu, Fiji Islands. This fungal pathogen has been implicated as the primary cause of amphibian declines worldwide. Few cases have been reported from tropical Asia however it was recently documented in 4 species of frogs in Indonesia. Two hundred individual frogs were swabbed from 5 different sites on Viwa Island. Swabs were tes...

  17. Mycoloop: chytrids in aquatic food webs.

    Science.gov (United States)

    Kagami, Maiko; Miki, Takeshi; Takimoto, Gaku

    2014-01-01

    Parasites are ecologically significant in various ecosystems through their role in shaping food web structure, facilitating energy transfer, and controlling disease. Here in this review, we mainly focus on parasitic chytrids, the dominant parasites in aquatic ecosystems, and explain their roles in aquatic food webs, particularly as prey for zooplankton. Chytrids have a free-living zoosporic stage, during which they actively search for new hosts. Zoospores are excellent food for zooplankton in terms of size, shape, and nutritional quality. In the field, densities of chytrids can be high, ranging from 10(1) to 10(9) spores L(-1). When large inedible phytoplankton species are infected by chytrids, nutrients within host cells are transferred to zooplankton via the zoospores of parasitic chytrids. This new pathway, the "mycoloop," may play an important role in shaping aquatic ecosystems, by altering sinking fluxes or determining system stability. The grazing of zoospores by zooplankton may also suppress outbreaks of parasitic chytrids. A food web model demonstrated that the contribution of the mycoloop to zooplankton production increased with nutrient availability and was also dependent on the stability of the system. Further studies with advanced molecular tools are likely to discover greater chytrid diversity and evidence of additional mycoloops in lakes and oceans. PMID:24795703

  18. Mycoloop: chytrids in aquatic food webs

    Directory of Open Access Journals (Sweden)

    Maiko eKagami

    2014-04-01

    Full Text Available Parasites are ecologically significant in various ecosystems through their role in shaping food web structure, facilitating energy transfer, and controlling disease. Here in this review, we mainly focus on parasitic chytrids, the dominant parasites in aquatic ecosystems, and explain their roles in aquatic food webs, particularly as prey for zooplankton. Chytrids have a free-living zoosporic stage, during which they actively search for new hosts. Zoospores are excellent food for zooplankton in terms of size, shape, and nutritional quality. In the field, densities of chytrids can be high, ranging from 101-109 spores L-1. When large inedible phytoplankton species are infected by chytrids, nutrients within host cells are transferred to zooplankton via the zoospores of parasitic chytrids. This new pathway, the ‘mycoloop,’ may play an important role in shaping aquatic ecosystems, by altering sinking fluxes or determining system stability. The grazing of zoospores by zooplankton may also suppress outbreaks of parasitic chytrids. A food web model demonstrated that the contribution of the mycoloop to zooplankton production increased with nutrient availability and was also dependent on the stability of the system. Further studies with advanced molecular tools are likely to discover greater chytrid diversity and evidence of additional mycoloops in lakes and oceans.

  19. Presence of the amphibian chytrid pathogen confirmed in Cameroon

    Czech Academy of Sciences Publication Activity Database

    Baláž, V.; Kopecký, O.; Gvoždík, Václav

    2012-01-01

    Roč. 22, č. 3 (2012), s. 191-194. ISSN 0268-0130 R&D Projects: GA MŠk LC06073 Institutional support: RVO:67985904 Keywords : Afromontane * chytridiomycosis * Congolian lowland rainforests Subject RIV: EG - Zoology Impact factor: 1.081, year: 2012

  20. Batrachochytrium salamandrivorans sp nov causes lethal chytridiomycosis in amphibians

    OpenAIRE

    Martel, An; Spitzen - van der Sluijs, Annemarieke; Blooi, Mark; Bert, Wim; Ducatelle, Richard; Fisher, Matthew C; Woeltjes, Antonius; Bosman, Wilbert; Chiers, Koen; Bossuyt, Franky; Pasmans, Frank

    2013-01-01

    Chytridiomycosis has resulted in the serious decline and extinction of >200 species of amphibians worldwide and poses the greatest threat to biodiversity of any known disease. This fungal disease is currently known to be caused by Batrachochytrium dendrobatidis, hitherto the only species within the entire phylum of the Chytridiomycota known to parasitize vertebrate hosts. We describe the discovery of a second highly divergent, chytrid pathogen, Batrachochytrium salamandrivorans sp. nov., that...

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

    Science.gov (United States)

    Olson, Deanna H.; Blaustein, Andrew R.

    2016-01-01

    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, especially for

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

    Directory of Open Access Journals (Sweden)

    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

  3. Reptiles, Amphibians, and Salmonella

    Science.gov (United States)

    ... What's this? Submit Button Past Emails CDC Features Reptiles, Amphibians, and Salmonella Language: English Español (Spanish) Recommend ... live. How do people get Salmonella infections from reptiles and amphibians? Reptiles and amphibians might have Salmonella ...

  4. 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. [...

  5. Endangered Frogs Coexist with Fungus Once Thought Fatal

    OpenAIRE

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

    2004-01-01

    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 ...

  6. Phylogeny and biogeography of an uncultured clade of snow chytrids.

    Science.gov (United States)

    Naff, C S; Darcy, J L; Schmidt, S K

    2013-10-01

    Numerous studies have shown that snow can contain a diverse array of algae known as 'snow algae'. Some reports also indicate that parasites of algae (e.g. chytrids) are also found in snow, but efforts to phylogenetically identify 'snow chytrids' have not been successful. We used culture-independent molecular approaches to phylogenetically identify chytrids that are common in long-lived snowpacks of Colorado and Europe. The most remarkable finding of the present study was the discovery of a new clade of chytrids that has representatives in snowpacks of Colorado and Switzerland and cold sites in Nepal and France, but no representatives from warmer ecosystems. This new clade ('Snow Clade 1' or SC1) is as deeply divergent as its sister clade, the Lobulomycetales, and phylotypes of SC1 show significant (P snow chytrids were phylogenetically shown to be in the order Rhizophydiales, a group with known algal parasites and saprotrophs. We suggest that these newly discovered snow chytrids are important components of snow ecosystems where they contribute to snow food-web dynamics and the release of nutrients due to their parasitic and saprotrophic activities. PMID:23551529

  7. Chytrids dominate arctic marine fungal communities.

    Science.gov (United States)

    Hassett, B T; Gradinger, R

    2016-06-01

    Climate change is altering Arctic ecosystem structure by changing weather patterns and reducing sea ice coverage. These changes are increasing light penetration into the Arctic Ocean that are forecasted to increase primary production; however, increased light can also induce photoinhibition and cause physiological stress in algae and phytoplankton that can favour disease development. Fungi are voracious parasites in many ecosystems that can modulate the flow of carbon through food webs, yet are poorly characterized in the marine environment. We provide the first data from any marine ecosystem in which fungi in the Chytridiomycota dominate fungal communities and are linked in their occurrence to light intensities and algal stress. Increased light penetration stresses ice algae and elevates disease incidence under reduced snow cover. Our results show that chytrids dominate Arctic marine fungal communities and have the potential to rapidly change primary production patterns with increased light penetration. PMID:26754171

  8. Cool Temperatures Reduce Antifungal Activity of Symbiotic Bacteria of Threatened Amphibians – Implications for Disease Management and Patterns of Decline

    OpenAIRE

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

    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 re...

  9. Freeze tolerance of soil chytrids from temperate climates in Australia.

    Science.gov (United States)

    Gleason, Frank H; Letcher, Peter M; McGee, Peter A

    2008-08-01

    Very little is known about the capacity of soil chytrids to withstand freezing in the field. Tolerance to freezing was tested in 21 chytrids isolated from cropping and undisturbed soils in temperate Australia. Samples of thalli grown on peptone-yeast-glucose (PYG) agar were incubated for seven days at -15 degrees C. Recovery of growth after thawing and transferring to fresh medium at 20 degrees C indicated survival. All isolates in the Blastocladiales and Spizellomycetales survived freezing in all tests. All isolates in the Chytridiales also survived freezing in some tests. None of the isolates in the Rhizophydiales survived freezing in any of the tests. However, some isolates in the Rhizophydiales recovered growth after freezing if they were grown on PYG agar supplemented with either 1% sodium chloride or 1% glycerol prior to freezing. After freezing, the morphology of the thalli of all isolates was observed under LM. In those isolates that recovered growth after transfer to fresh media, mature zoosporangia were observed in the monocentric isolates and resistant sporangia or resting spores in the polycentric isolates. Encysted zoospores in some monocentric isolates also survived freezing. In some of the experiments the freezing and thawing process caused visible structural damage to the thalli. The production of zoospores after freezing and thawing was also used as an indicator of freeze tolerance. The chytrids in this study responded differently to freezing. These data add significantly to our limited knowledge of freeze tolerance in chytrids but leave many questions unanswered. PMID:18550351

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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

  12. Tolerance of fungal infection in European water frogs exposed to Batrachochytrium dendrobatidis after experimental reduction of innate immune defenses

    OpenAIRE

    Woodhams Douglas C; Bigler Laurent; Marschang Rachel

    2012-01-01

    Abstract Background While emerging diseases are affecting many populations of amphibians, some populations are resistant. Determining the relative contributions of factors influencing disease resistance is critical for effective conservation management. Innate immune defenses in amphibian skin are vital host factors against a number of emerging pathogens such as ranaviruses and the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). Adult water frogs from Switzerland (Pelophylax esc...

  13. The emerging amphibian pathogen Batrachochytrium dendrobatidis globally infects introduced populations of the North American bullfrog, Rana catesbeiana

    OpenAIRE

    Trenton W J Garner; Perkins, Matthew W.; Govindarajulu, Purnima; Seglie, Daniele; Walker, Susan; Cunningham, Andrew A.; Fisher, Matthew C

    2006-01-01

    Batrachochytrium dendrobatidis is the chytridiomycete fungus which has been implicated in global amphibian declines and numerous species extinctions. Here, we show that introduced North American bullfrogs (Rana catesbeiana) consistently carry this emerging pathogenic fungus. We detected infections by this fungus on introduced bullfrogs from seven of eight countries using both PCR and microscopic techniques. Only native bullfrogs from eastern Canada and introduced bullfrogs from Japan showed n...

  14. Parasitic chytrids sustain zooplankton growth during inedible algal bloom.

    Science.gov (United States)

    Rasconi, Serena; Grami, Boutheina; Niquil, Nathalie; Jobard, Marlène; Sime-Ngando, Télesphore

    2014-01-01

    This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of "inedible" algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19-20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin. PMID:24904543

  15. Parasitic Chytrids sustain zooplankton growth during inedible algal bloom

    Directory of Open Access Journals (Sweden)

    SerenaRasconi

    2014-05-01

    Full Text Available This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom of Lake Pavin (oligo-mesotrophic and the autumn cyanobacteria bloom of Lake Aydat (eutrophic. Linear inverse modelling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modelling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the probable impact of parasites on food web function as grazers and recyclers. During blooms of “inedible” algae (unexploited by planktonic herbivores, the epidemic growth of chytrids channelled 19-20% of the primary production in both lakes through the production of grazer-exploitable zoospores. The parasitic throughput represents 50 and 57% of the zooplankton diet respectively in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin.# The first two authors contributed equally to this work

  16. Early 1900s Detection of Batrachochytrium dendrobatidis in Korean Amphibians

    OpenAIRE

    Fong, Jonathan J.; Cheng, Tina L.; Bataille, Arnaud; Allan P Pessier; Waldman, Bruce; Vance T Vredenburg

    2015-01-01

    The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa), collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of t...

  17. Fungus Amongus

    Science.gov (United States)

    Wakeley, Deidra

    2005-01-01

    This role-playing simulation is designed to help teach middle level students about the typical lifecycle of a fungus. In this interactive simulation, students assume the roles of fungi, spores, living and dead organisms, bacteria, and rain. As they move around a playing field collecting food and water chips, they discover how the organisms…

  18. 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…

  19. Assessing the ability of swab data to determine the true burden of infection for the amphibian pathogen Batrachochytrium dendrobatidis

    OpenAIRE

    Clare, F.; Daniel, O; Garner, T.; Fisher, M.

    2016-01-01

    Batrachochytrium dendrobatidis (Bd) is a pathogenic fungus which causes the disease chytridiomycosis in amphibians by infecting the animals’ epidermis. The most commonly applied method for the detection of Bd is the use of a sterile swab, rubbed over the keratinized areas of an amphibian and then processed to yield DNA for detection by qPCR. This method has been used to infer a threshold of lethal infection in some species; however, how reliable and reproducible the swabbing method is at dete...

  20. The Structure and Function of Amphibian Skin Bacterial Communities and Their Role in Susceptibility to a Fungal Pathogen

    OpenAIRE

    Walke, Jenifer Banning

    2014-01-01

    As part of the ongoing loss of global biodiversity, amphibian populations are experiencing declines and extinctions. A primary factor in these declines is the skin disease chytridiomycosis, which is caused by the fungus Batrachochytrium dendrobatidis (Bd). Recent research suggests that the amphibian skin microbiota has anti-Bd activity and may be an important factor in host disease resistance. However, little is known about the basic ecology of this host-microbe symbiosis, such as how much va...

  1. Distribution of the amphibian pathogen Batrachochytrium dendrobatidis in the Pacific Northwestern USA

    Science.gov (United States)

    Pearl, Christopher A.; Bull, E.L.; Green, D.E.; Bowerman, Jay; Adams, Michael J.; Hyatt, A.; Wente, W.

    2007-01-01

    Chytridiomycosis (infection by the fungus Batrachochytrium dendrobatidis) has been associated with amphibian declines in at least four continents. We report results of disease screens from 210 pond-breeding amphibians from 37 field sites in Oregon and Washington. We detected B. dendrobatidis on 28% of sampled amphibians, and we found a?Y 1 detection of B. dendrobatidis from 43% of sites. Four of seven species tested positive for B. dendrobatidis, including the Northern Red-Legged Frog (Rana aurora), Columbia Spotted Frog (Rana luteiventris), and Oregon Spotted Frog (Rana pretiosa). We also detected B. dendrobatidis in nonnative American Bullfrogs (Rana catesbeiana) from six sites in western and central Oregon. Our study and other recently published findings suggest that B. dendrobatidis has few geographic and host taxa limitations among North American anurans. Further research on virulence, transmissibility, persistence, and interactions with other stressors is needed to assess the potential impact of B. dendrobatidis on Pacific Northwestern amphibians.

  2. Amphibians of Peninsular India

    OpenAIRE

    Gururaja, KV

    2005-01-01

    Frogs and toads have always fascinated man through the ages, dating back to Mandukya Upanishad of the Vedic ages to the cent discoveries in the Western Ghats. More technically known as ‘amphibians’ (Greek equivalent for their biphasic life stages as tadpoles and adults), these include caecilians, salamanders, newts, and sirens. Amphibians are in serious scientific contention over the last decade for at least two main reasons. One being far more crucial, pertaining to their viable existence as...

  3. A non-lethal technique for detecting the chytrid fungus Batrachochytrium dendrobatidis on tadpoles.

    Science.gov (United States)

    Retallick, Richard W R; Miera, Verma; Richards, Kathryn L; Field, Kimberleigh J; Collins, James P

    2006-09-14

    Batrachochytrium dendrobatidis (Bd) infection on post-metamorphic frogs and salamanders is commonly diagnosed using polymerase chain reaction (PCR) of skin scrapings taken with mildly abrasive swabs. The technique is sensitive, non-lethal, and repeatable for live animals. Tadpoles are generally not sampled by swabbing but are usually killed and their mouthparts excised to test for the pathogen. We evaluated a technique for non-lethal Bd diagnosis using quantitative PCR (qPCR) on swabs scraped over the mouthparts of live tadpoles. The sensitivity of non-lethal (swabbing) and lethal (removal of mouthparts) sampling was assessed using 150 Bd-infected Rana subaquavocalis tadpoles. Swabbing was consistently less sensitive than lethal sampling, but still detected Bd. Experimental Bd prevalence was 41.1% when estimated by destructively sampling mouthparts and 4.7 to 36.6% (mean = 21.4%) when estimated with swabs. Detection rates from swabbing varied with investigator and time since infection. The likelihood of detecting Bd-infected tadpoles was similar regardless of size and developmental stage. Swabbing mouthparts of live tadpoles is a feasible and effective survey technique for Bd, but, because it is less sensitive, more tadpoles must be sampled to estimate prevalence at a confidence level comparable to destructive sampling. PMID:17067076

  4. 'Salamander plague' on Britain's doorstep.

    Science.gov (United States)

    Mills, Georgina

    2015-01-24

    Chytridiomycosis can cause mass declines in amphibians, and the chytrid fungus Batrachochytrium dendrobatidis is the classic cause of this disease. However, recently, a second strain of chytrid fungus has emerged in Europe, resulting in major declines in fire salamanders. The Zoological Society of London (ZSL) discussed this, and the implications for the UK, at a meeting in December in London. Georgina Mills reports. PMID:25614547

  5. A new genus and family for the misclassified chytrid, Rhizophlyctis harderi.

    Science.gov (United States)

    Powell, Martha J; Letcher, Peter M; Chambers, James G; Roychoudhury, Sonali

    2015-01-01

    A chytrid first discovered in Mediterranean sands and called Rhizophlyctis harderi was classified in the genus Rhizophlyctis based on its interbiotic vegetative thalli with multiple rhizoidal axes and resting thalli with tufts of rhizoid-like appendages. Developmental, electron microscopic and molecular analyses, however, have brought into question the proper placement of this chytrid. Because its original description was in German and not Latin, the name R. harderi is not validly published. We found that this chytrid produces three thallus forms that could place it in three different morpho-genera: Rhizophydium, Phlyctochytrium or Rhizophlyctis. The ultrastructural architecture of its zoospore is different from that of zoospores of Rhizophlyctis rosea, the type species for Rhizophlyctis, and shares zoospore ultrastructural characteristics with the Rhizophydiales. Zoospores of this chytrid exhibit a distinctive kinetosome-associated structure (KAS), a curved shield bridged to two of the kinetosomal triplets and a layered cap anterior to the kinetosome. Phylogenetic analyses of nuc rDNA also support the placement of this chytrid in the Rhizophydiales and not in the Rhizophlyctidales. Given its molecularly based phylogenetic placement and its distinctive zoospore architecture, we describe this chytrid in a new genus, Uebelmesseromyces, in the Rhizophydiales and erect Uebelmesseromycetaceae as a new family to accommodate it. PMID:25572098

  6. Early 1900 s detection of Batrachochytrium dendrobatidis in Korean amphibians.

    Science.gov (United States)

    Fong, Jonathan J; Cheng, Tina L; Bataille, Arnaud; Pessier, Allan P; Waldman, Bruce; Vredenburg, Vance T

    2015-01-01

    The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa), collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of these positive specimens revealed mild hyperkeratosis - a non-specific host response commonly found in Bd-infected frogs - but no Bd zoospores or zoosporangia. Our results indicate that Bd was present in Korea more than 100 years ago, consistent with hypotheses suggesting that Korean amphibians may be infected by endemic Asian Bd strains. PMID:25738656

  7. Early 1900 s detection of Batrachochytrium dendrobatidis in Korean amphibians.

    Directory of Open Access Journals (Sweden)

    Jonathan J Fong

    Full Text Available The pathogenic fungus Batrachochytrium dendrobatidis (Bd is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa, collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of these positive specimens revealed mild hyperkeratosis - a non-specific host response commonly found in Bd-infected frogs - but no Bd zoospores or zoosporangia. Our results indicate that Bd was present in Korea more than 100 years ago, consistent with hypotheses suggesting that Korean amphibians may be infected by endemic Asian Bd strains.

  8. Motile zoospores of Batrachochytrium dendrobatidis move away from antifungal metabolites produced by amphibian skin bacteria.

    Science.gov (United States)

    Lam, Brianna A; Walton, D Brian; Harris, Reid N

    2011-03-01

    Chytridiomycosis is an amphibian skin disease that threatens amphibian biodiversity worldwide. The fungal agent of chytridiomycosis is Batrachochytrium dendrobatidis. There is considerable variation in disease outcomes such that some individuals and populations co-exist with the fungus and others quickly succumb to disease. Amphibians in populations that co-exist with the B. dendrobatidis have sublethal infections on their skins. Symbiotic skin bacteria have been shown in experiments and surveys to play a role in protecting amphibians from chytridiomycosis. Little is known about the mechanisms that antifungal skin bacteria use to ameliorate the effects of B. dendrobatidis. In this study, we identified that B. dendrobatidis isolate JEL 310 zoospores display chemotaxis, in the presence of two bacterially-produced metabolites (2,4-diacetylphloroglucinol and indole-3-carboxaldehyde). In the presence of either metabolite, B. dendrobatidis zoospores move more frequently away from the metabolite. Using parameters estimated from this study, a simple stochastic model of a random walk on a lattice was evaluated. The model shows that these individual behaviors over short time-scales directly lead to population behaviors over long time-scales, such that most zoospores will escape, or not infect a tryptone substrate containing the bacterially-produced metabolite, whereas many zoospores will infect the tryptone substrate containing no metabolite. These results suggest that amphibians that have skin bacteria produce antifungal metabolites that might be able to keep B. dendrobatidis infections below the lethal threshold and thus are able to co-exist with the fungus. PMID:21769695

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

    Science.gov (United States)

    Ruggeri, Joice; Longo, Ana V.; Gaiarsa, Marília P.; Alencar, Laura R. V.; Lambertini, Carolina; Leite, Domingos S.; Carvalho-e-Silva, Sergio P.; Zamudio, Kelly R.; Toledo, Luís Felipe; Martins, Marcio

    2015-01-01

    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. PMID:26161777

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Widespread amphibian extinctions from epidemic disease driven by global warming.

    Science.gov (United States)

    Pounds, J Alan; Bustamante, Martín R; Coloma, Luis A; Consuegra, Jamie A; Fogden, Michael P L; Foster, Pru N; La Marca, Enrique; Masters, Karen L; Merino-Viteri, Andrés; Puschendorf, Robert; Ron, Santiago R; Sánchez-Azofeifa, G Arturo; Still, Christopher J; Young, Bruce E

    2006-01-12

    As the Earth warms, many species are likely to disappear, often because of changing disease dynamics. Here we show that a recent mass extinction associated with pathogen outbreaks is tied to global warming. Seventeen years ago, in the mountains of Costa Rica, the Monteverde harlequin frog (Atelopus sp.) vanished along with the golden toad (Bufo periglenes). An estimated 67% of the 110 or so species of Atelopus, which are endemic to the American tropics, have met the same fate, and a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) is implicated. Analysing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with 'very high confidence' (> 99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances. We propose that temperatures at many highland localities are shifting towards the growth optimum of Batrachochytrium, thus encouraging outbreaks. With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable. PMID:16407945

  12. Short-Term Exposure to Warm Microhabitats Could Explain Amphibian Persistence with Batrachochytrium dendrobatidis

    OpenAIRE

    Daskin, Joshua H.; Ross A. Alford; 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...

  13. 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...

  14. Occurrence of the amphibian pathogen Batrachochytrium dendrobatidis in the Pacific Northwest

    Science.gov (United States)

    Pearl, C.A.; Bull, E.L.; Green, D.E.; Bowerman, J.; Adams, M.J.; Hyatt, A.; Wente, W.H.

    2007-01-01

    Chytridiomycosis (infection by the fungus Batrachochytrium dendrobatidis) has been associated with amphibian declines in at least four continents. We report results of disease screens from 210 pond-breeding amphibians from 37 field sites in Oregon and Washington. We detected B. dendrobatidis on 28% of sampled amphibians, and we found ??? 1 detection of B. dendrobatidis from 43% of sites. Four of seven species tested positive for B. dendrobatidis, including the Northern Red-Legged Frog (Rana aurora), Columbia Spotted Frog (Rana luteiventris), and Oregon Spotted Frog (Rana pretiosa). We also detected B. dendrobatidis in nonnative American Bullfrogs (Rana catesbeiana) from six sites in western and central Oregon. Our study and other recently published findings suggest that B. dendrobatidis has few geographic and host taxa limitations among North American anurans. Further research on virulence, transmissibility, persistence, and interactions with other stressors is needed to assess the potential impact of B. dendrobatidis on Pacific Northwestern amphibians. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  15. Agricultural ponds support amphibian populations

    Science.gov (United States)

    Knutson, M.G.; Richardson, W.B.; Reineke, D.M.; Gray, B.R.; Parmelee, J.R.; Weick, S.E.

    2004-01-01

    In some agricultural regions, natural wetlands are scarce, and constructed agricultural ponds may represent important alternative breeding habitats for amphibians. Properly managed, these agricultural ponds may effectively increase the total amount of breeding habitat and help to sustain populations. We studied small, constructed agricultural ponds in southeastern Minnesota to assess their value as amphibian breeding sites. Our study examined habitat factors associated with amphibian reproduction at two spatial scales: the pond and the landscape surrounding the pond. We found that small agricultural ponds in southeastern Minnesota provided breeding habitat for at least 10 species of amphibians. Species richness and multispecies reproductive success were more closely associated with characteristics of the pond (water quality, vegetation, and predators) compared with characteristics of the surrounding landscape, but individual species were associated with both pond and landscape variables. Ponds surrounded by row crops had similar species richness and reproductive success compared with natural wetlands and ponds surrounded by nongrazed pasture. Ponds used for watering livestock had elevated concentrations of phosphorus, higher turbidity, and a trend toward reduced amphibian reproductive success. Species richness was highest in small ponds, ponds with lower total nitrogen concentrations, tiger salamanders (Ambystoma tigrinum) present, and lacking fish. Multispecies reproductive success was best in ponds with lower total nitrogen concentrations, less emergent vegetation, and lacking fish. Habitat factors associated with higher reproductive success varied among individual species. We conclude that small, constructed farm ponds, properly managed, may help sustain amphibian populations in landscapes where natural wetland habitat is rare. We recommend management actions such as limiting livestock access to the pond to improve water quality, reducing nitrogen input, and

  16. 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.

  17. 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.

  18. Ecopathology of Ranaviruses Infecting Amphibians

    Directory of Open Access Journals (Sweden)

    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.

  19. METAPOPULATION DYNAMICS AND AMPHIBIAN CONSERVATION

    Science.gov (United States)

    In many respects, amphibian spatial dynamics resemble classical metapopulation models, where subpopulations in breeding ponds blink in and out of existance and where extinction and colonization rates are functions of pond spatial arrangement. This "ponds-as-patches" view of amphi...

  20. AMPHIBIAN MITIGATION MEASURES IN CENTRAL-EUROPE

    OpenAIRE

    Puky, Miklós

    2003-01-01

    Studies from different continents have proved amphibians to be the most frequently killed vertebrates on roads. In Central-Europe their ratio is between 70 and 88 percent. Local populations are known to become extinct or genetically isolated, and avoidance is also recognised, especially where the road network is dense and the traffi c is intensive. Besides ecological and conservation considerations, amphibian road kills also present a hazard for motorists when amphibians migrate in large numb...

  1. 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....

  2. Tremella with Edible Fungus

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    (Meiwei Shuang’er)Remove the tremella and edible fungus roots, clean and drain. Slice green peppers and carrots.Heat some oil in a wok, add tremella, edible fungus, green peppers and carrots, and clear stock, salt and sugar. Simmer for two minutes. Add MSG and pepper, remove to a plate, and serve.Features: Attractively black and white.Taste: Crisp and savory.

  3. Survey of helminths, ectoparasites, and chytrid fungus of an introduced population of cane toads, Rhinella marina (Anura: Bufonidae), from Grenada

    Science.gov (United States)

    Drake, Michael C.; Zieger, Ulrike; Groszkowski, Andrew; Gallardo, Bruce; Sages, Patti; Reavis, Roslyn; Faircloth, Leslie; Jacobson, Krystin; Lonce, Nicholas; Pinckney, Rhonda D.; Cole, Rebecca Ann

    2014-01-01

    One hundred specimens of Rhinella marina, (Anura: Bufonidae) collected in St. George's parish, Grenada, from September 2010 to August 2011, were examined for the presence of ectoparasites and helminths. Ninety-five (95%) toads were parasitized by one or more parasite species. Nine species of parasites were found: 1 digenean, 2 acanthocephalans, 4 nematodes, 1 arthropod and 1 pentastome. The endoparasites represented 98.9% of the total number of parasite specimens collected. Grenada represents a new locality record for Mesocoelium monas, Raillietiella frenatus, Pseudoacanthacephalus sp., Aplectana sp., Physocephalus sp., Acanthacephala cystacanth and Physalopteridae larvae. The digenean M. monas occurred with the highest prevalence of 82%, contrasting many studies of R. marina where nematodes dominate the parasite infracommunity. Female toads were found to have a significantly higher prevalence of Amblyomma dissimile than male toads. Only two parasites exhibited a significant difference between wet and dry season with Parapharyngodon grenadensis prevalence highest in the wet season and A. dissimile prevalence highest during the dry season. Additionally, A. dissimile was significantly more abundant during the dry season.

  4. 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. PMID:19143783

  5. The pathogen Batrachochytrium dendrobatidis disturbs the frog skin microbiome during a natural epidemic and experimental infection

    OpenAIRE

    Jani, Andrea J.; Cheryl J Briggs

    2014-01-01

    Animals are inhabited by communities of microbes (the microbiome) that potentially interact with pathogens. Detailed studies of microbiome–pathogen interactions in nature are rare, and even when correlations are observed, determining causal relationships is challenging. The microbiome–pathogen relationship is of particular interest in the case of Batrachochytrium dendrobatidis, a chytrid fungus that infects the skin of amphibians and is causing amphibian declines worldwide. We documented a st...

  6. Hydrological Regimes, Pond Morphology, and Habitat Use: Predicting the Impact of an Emerging Aquatic Pathogen

    OpenAIRE

    Cheryl J Briggs

    2006-01-01

    Declines in amphibian populations have been reported throughout the world in recent years. Chytridiomycosis, a disease of amphibians caused by the chytrid fungus, Batrachochytrium dendrobatidis, is one of a number of factors that have been shown to contribute to these population declines. B. dendrobatidis is associated with rapid population declines and local extinctions of populations of mountain yellow-legged frog, Rana muscosa, in some areas of the California Sierra Nevada mountains, howev...

  7. Field and Laboratory Studies of the Susceptibility of the Green Treefrog (Hyla cinerea) to Batrachochytrium dendrobatidis Infection

    OpenAIRE

    Laura A Brannelly; Chatfield, Matthew W. H.; Richards-Zawacki, Corinne L.

    2012-01-01

    Amphibians worldwide are experiencing devastating declines, some of which are due to the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd). Populations in the southeastern United States, however, have not been noticeably affected by the pathogen. The green treefrog (Hyla cinerea) is abundant and widespread in the southeastern United States, but has not been documented to harbor Bd infection. This study examined the susceptibility of H. cinerea to two strains of Bd in the lab and t...

  8. Seasonal Ecology and Behavior of an Endangered Rainforest Frog (Litoria rheocola) Threatened by Disease

    OpenAIRE

    Elizabeth A Roznik; Ross A. Alford

    2015-01-01

    One of the most devastating wildlife diseases ever recorded is chytridiomycosis, a recently emerged amphibian disease that is caused by the chytrid fungus Batrachochytrium dendrobatidis. Understanding, predicting, and managing the impacts of chytridiomycosis on any amphibian species will require detailed information on its ecology and behavior because this pathogen is transmitted by contact with water or other individuals, and pathogen growth rates are thermally sensitive. The common mistfrog...

  9. Inhibition of Batrachochytrium dendrobatidis Caused by Bacteria Isolated from the Skin of Boreal Toads, Anaxyrus (Bufo) boreas boreas, from Grand Teton National Park, Wyoming, USA

    OpenAIRE

    Park, Shawna T; Collingwood, Amanda M; Sophie St-Hilaire; Sheridan, Peter P.

    2014-01-01

    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 inhibit...

  10. A checklist of amphibians of Kerala, India

    Directory of Open Access Journals (Sweden)

    Sandeep Das

    2015-11-01

    Full Text Available A checklist of amphibians of Kerala State is presented in this paper.  Accepted English names, scientific binomen,  vernacular names in Malayalam, IUCN conservation status, endemism, Indian Wildlife (Protection Act schedules, and the appendices in the CITES, pertaining to the amphibians of Kerala are also given.  The State of Kerala has 151 species of amphibians, 136 of which are endemic to Western Ghats and 50 species fall under the various threatened categories of IUCN.  

  11. Amphibian macrophage development and antiviral defenses.

    Science.gov (United States)

    Grayfer, Leon; Robert, Jacques

    2016-05-01

    Macrophage lineage cells represent the cornerstone of vertebrate physiology and immune defenses. In turn, comparative studies using non-mammalian animal models have revealed that evolutionarily distinct species have adopted diverse molecular and physiological strategies for controlling macrophage development and functions. Notably, amphibian species present a rich array of physiological and environmental adaptations, not to mention the peculiarity of metamorphosis from larval to adult stages of development, involving drastic transformation and differentiation of multiple new tissues. Thus it is not surprising that different amphibian species and their respective tadpole and adult stages have adopted unique hematopoietic strategies. Accordingly and in order to establish a more comprehensive view of these processes, here we review the hematopoietic and monopoietic strategies observed across amphibians, describe the present understanding of the molecular mechanisms driving amphibian, an in particular Xenopus laevis macrophage development and functional polarization, and discuss the roles of macrophage-lineage cells during ranavirus infections. PMID:26705159

  12. Maryland 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 sea turtles, estuarine turtles, and rare reptiles and amphibians in Maryland. Vector polygons in this...

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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 to free-living Bd in aquatic

  16. Direct and Indirect Effects of Climate Change on Amphibian Populations

    OpenAIRE

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

    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...

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

    OpenAIRE

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

    2010-01-01

    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 hav...

  18. Microbiota and mucosal immunity in amphibians

    Directory of Open Access Journals (Sweden)

    Bruno M Colombo

    2015-03-01

    Full Text Available We know that animals live in a world dominated by bacteria. In the last twenty years we have learned that microbes are essential regulators of mucosal immunity. Bacterias, archeas and viruses influence different aspects of mucosal development and function. Yet the literature mainly covers findings obtained in mammals. In this review, we focus on two major themes that emerge from the comparative analysis of mammals and amphibians. These themes concern: i the structure and functions of lymphoid organs and immune cells in amphibians, with a focus on the gut mucosal immune system; and ii the characteristics of the amphibian microbiota and its influence on mucosal immunity. Lastly, we propose to use Xenopus tadpoles as an alternative small animal model to improve the fundamental knowledge on immunological functions of gut microbiota.

  19. Where to look when identifying roadkilled amphibians?

    Directory of Open Access Journals (Sweden)

    Marc Franch

    2015-12-01

    Full Text Available Roads have multiple effects on wildlife; amphibians are one of the groups more intensely affected by roadkills. Monitoring roadkills is expensive and time consuming. Automated mapping systems for detecting roadkills, based on robotic computer vision techniques, are largely necessary. Amphibians can be recognised by a set of features as shape, size, colouration, habitat and location. This species identification by using multiple features at the same time is known as “jizz”. In a similar way to human vision, computer vision algorithms must incorporate a prioritisation process when analysing the objects in an image. Our main goal here was to give a numerical priority sequence of particular characteristics of roadkilled amphibians to improve the computing and learning process of algorithms. We asked hundred and five amateur and professional herpetologists to answer a simple test of five sets with ten images each of roadkilled amphibians, in order to determine which body parts or characteristics (body form, colour, and other patterns are used to identify correctly the species. Anura was the group most easily identified when it was roadkilled and Caudata was the most difficult. The lower the taxonomic level of amphibian, the higher the difficulty of identifying them, both in Anura and Caudata. Roadkilled amphibians in general and Anura group were mostly identified by the Form, by the combination of Form and Colour, and finally by Colour. Caudata was identified mainly on Form and Colour and on Colour. Computer vision algorithms must incorporate these combinations of features, avoiding to work exclusively in one specific feature.

  20. 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

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

    Directory of Open Access Journals (Sweden)

    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

  2. Culture of Cells from Amphibian Embryos.

    Science.gov (United States)

    Stanisstreet, Martin

    1983-01-01

    Describes a method for in vitro culturing of cells from amphibian early embryos. Such cells can be used to demonstrate such properties of eukaryote cells as cell motility, adhesion, differentiation, and cell sorting into tissues. The technique may be extended to investigate other factors. (Author/JN)

  3. Amphibian pathogens in Southeast Asian frog trade.

    Science.gov (United States)

    Gilbert, Martin; Bickford, David; Clark, Leanne; Johnson, Arlyne; Joyner, Priscilla H; Ogg Keatts, Lucy; Khammavong, Kongsy; Nguyễn Văn, Long; Newton, Alisa; Seow, Tiffany P W; Roberton, Scott; Silithammavong, Soubanh; Singhalath, Sinpakhone; Yang, Angela; Seimon, Tracie A

    2012-12-01

    Amphibian trade is known to facilitate the geographic spread of pathogens. Here we assess the health of amphibians traded in Southeast Asia for food or as pets, focusing on Batrachochytrium dendrobatidis (Bd), ranavirus and general clinical condition. Samples were collected from 2,389 individual animals at 51 sites in Lao PDR, Cambodia, Vietnam and Singapore for Bd screening, and 74 animals in Cambodia and Vietnam for ranavirus screening. Bd was found in one frog (n = 347) in Cambodia and 13 in Singapore (n = 419). No Bd was found in Lao PDR (n = 1,126) or Vietnam (n = 497), and no ranavirus was found in Cambodia (n = 70) or Vietnam (n = 4). Mild to severe dermatological lesions were observed in all East Asian bullfrogs Hoplobatrachus rugolosus (n = 497) sampled in farms in Vietnam. Histologic lesions consistent with sepsis were found within the lesions of three frogs and bacterial sepsis in two (n = 4); one had Gram-negative bacilli and one had acid-fast organisms consistent with mycobacterium sp. These results confirm that Bd is currently rare in amphibian trade in Southeast Asia. The presence of Mycobacterium-associated disease in farmed H. rugolosus is a cause for concern, as it may have public health implications and indicates the need for improved biosecurity in amphibian farming and trade. PMID:23404036

  4. POTENTIAL DEVELOPMENTAL EFFECTS OF ATRAZINE ON AMPHIBIANS

    Science.gov (United States)

    Recent research has generated conflicting results on the effects of atrazine on gonadal developmental (e.g., male hermaphroditism) in amphibians and how these effects influence secondary sexual characteristics (e.g., laryngeal muscle mass). The SAP is being asked to consider the...

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

    Science.gov (United States)

    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. PMID:25819009

  6. Microbiome Variation Across Amphibian Skin Regions: Implications for Chytridiomycosis Mitigation Efforts.

    Science.gov (United States)

    Bataille, Arnaud; Lee-Cruz, Larisa; Tripathi, Binu; Kim, Hyoki; Waldman, Bruce

    2016-01-01

    Cutaneous bacteria may play an important role in the resistance of amphibians to the pathogenic fungus Batrachochytrium dendrobatidis (Bd). Microbial communities resident on hosts' skin show topographical diversity mapping to skin features, as demonstrated by studies of the human microbiome. We examined skin microbiomes of wild and captive fire-bellied toads (Bombina orientalis) for differences across their body surface. We found that bacterial communities differed between ventral and dorsal skin. Wild toads showed slightly higher bacterial richness and diversity in the dorsal compared to the ventral region. On the other hand, captive toads hosted a higher richness and diversity of bacteria on their ventral than their dorsal skin. Microbial community composition and relative abundance of major bacterial taxonomic groups also differed between ventral and dorsal skin in all populations. Furthermore, microbiome diversity patterns varied as a function of their Bd infection status in wild toads. Bacterial richness and diversity was greater, and microbial community structure more complex, in wild than captive toads. The results suggest that bacterial community structure is influenced by microhabitats associated with skin regions. These local communities may be differentially modified when interacting with environmental bacteria and Bd. A better understanding of microbiome variation across skin regions will be needed to assess how the skin microbiota affects the abilities of amphibian hosts to resist Bd infection, especially in captive breeding programs. PMID:26271741

  7. Helping Your Local Amphibians (HYLA): An Internet-Based Amphibian Course for Educators

    Science.gov (United States)

    Murphy, Tony P.

    2001-12-01

    A pilot on-line course on amphibians was offered free to 20 educators around the United States in 1999. This course, called Helping Your Local Amphibians (HYLA), was the first of its kind on-line course for educators dealing with amphibian issues. It also used these animals as a focus to teach about the environment. The course lasted 9 weeks with some additional time for continued discussions and used various aspects of Internet technology (including a virtual conference center), media, and traditional paper-based products to complete the learning process. Five teachers were selected to attend a national amphibian summit hosted by the Center for Global Environmental Education, Hamline University, St. Paul, MN. The course was aimed primarily at upper elementary and middle school teachers, but participants included formal and nonformal educators. For the most part, educators expressed satisfaction with the course and the content, as well as the structure of the web site. For 80% of the group, this was their first Internet-based course. In addition, as part of the course, the educators were expected to take some action with their primary audiences to help local amphibian populations. This mainly took the form of surveys or habitat clean-ups. The development of the course was underwritten by grants from the National Fish and Wildlife Foundation, U.S. Fish and Wildlife Service, the Best Buy Children's Foundation, and Hamline University.

  8. Book review: Amphibians and reptiles in Minnesota

    Science.gov (United States)

    Mushet, David M.

    2014-01-01

    The photograph of a young boy poised to capture a wood frog (Lithobates sylvaticus) on page 3 of Amphibians and Reptiles in Minnesota captures perfectly the sense of awe and wonderment that one encounters throughout John Moriarty and Carol Hall’s new book. This is a spirit that most children possess naturally and that is so readily apparent when one of them comes face-to-face with one of the 53 species of frogs, toads, salamanders, turtles, lizards, or snakes that make Minnesota their home. This is a spirit that the authors have maintained in their hearts throughout almost 30 years of chasing, capturing, and studying amphibians and reptiles (a.k.a., herptiles or herps) in Minnesota. It is also the spirit that you will find reawakening in yourself as you turn from one page to the next and encounter the abundant color photos and descriptive text within this book.

  9. Effects of Roads on Amphibian Populations

    DEFF Research Database (Denmark)

    Hels, T.

    Lucky me to have had the chance of enjoying the barely audible sound of calling spadefoot toads on warm spring nights! Right at the breakthrough of spring they arrive at the breeding ponds, by the time when the air becomes heavy with the promising fragrances of spring and early summer. Lucky me to...... have experienced the wonders of early summer sunrises in the field - and the joy of thawing out frozen fingers after hours of field work around freezing point. Amphibian populations are declining. This worrying fact is what has initiated this work. Some fifty years ago, the life history of frogs and......, something to talk about. Fortunately, amphibians are still numerous in certain places and hopefully, we will get to a point when we know enough about the declines and their backgrounds to bring the decline to an end. It is my hope that results of this work will add a piece to the puzzle. This work is the...

  10. Direct and Indirect Effects of Climate Change on Amphibian Populations

    Directory of Open Access Journals (Sweden)

    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.

  11. 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.

  12. Amphibian road kills: a global perspective

    OpenAIRE

    Puky, Miklós

    2005-01-01

    Transportation infrastructure is a major factor determining land use forms. As global changes in this factor are the most important for biodiversity, roads fundamentally influence wildlife. The effect of roads on wildlife has been categorized in several ways resulting in six to ten categories with road kill as an obvious and important component, and amphibians are greatly affected by this factor. As this animal group has been documented to decline from multiple threats worldwide, the study an...

  13. The effect of road kills on amphibian populations

    OpenAIRE

    Hels, Tove; Buchwald,, Erik

    2001-01-01

    The diurnal movement patterns of Triturus vulgaris, T. cristatus, Pelobates fuscus, Bufo bufo, Rana temporaria, and R. arvalis were investigated during five breeding seasons (1994-1998). Two main questions were addressed: 1) What is the probability of an individual amphibian getting killed when crossing the road? and 2) What fraction of the amphibian populations gets killed by traffic? The rate of movement of 203 adult amphibians was recorded. Information on traffic loads was provided, and mo...

  14. Trends in Amphibian Occupancy in the United States

    OpenAIRE

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

    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 ...

  15. 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

  16. White-Nose Syndrome fungus introduced from Europe to North America.

    Science.gov (United States)

    Leopardi, Stefania; Blake, Damer; Puechmaille, Sébastien J

    2015-03-16

    The investigation of factors underlying the emergence of fungal diseases in wildlife has gained significance as a consequence of drastic declines in amphibians, where the fungus Batrachochytrium dendrobatidis has caused the greatest disease-driven loss of biodiversity ever documented [1]. Identification of the causative agent and its origin (native versus introduced) is a crucial step in understanding and controlling a disease [2]. Whereas genetic studies on the origin of B. dendrobatidis have illuminated the mechanisms behind the global emergence of amphibian chytridiomycosis [3], the origin of another recently-emerged fungal disease, White-Nose Syndrome (WNS) and its causative agent, Pseudogymnoascus destructans, remains unresolved [2,4]. WNS is decimating multiple North American bat species with an estimated death toll reaching 5-6 million. Here, we present the first informative molecular comparison between isolates from North America and Europe and provide strong evidence for the long-term presence of the fungus in Europe and a recent introduction into North America. Our results further demonstrate great genetic similarity between the North American and some European fungal populations, indicating the likely source population for this introduction from Europe. PMID:25784035

  17. Global rates of habitat loss and implications for amphibian conservation

    Science.gov (United States)

    Gallant, A.L.; Klaver, R.W.; Casper, G.S.; Lannoo, M.J.

    2007-01-01

    A large number of factors are known to affect amphibian population viability, but most authors agree that the principal causes of amphibian declines are habitat loss, alteration, and fragmentation. We provide a global assessment of land use dynamics in the context of amphibian distributions. We accomplished this by compiling global maps of amphibian species richness and recent rates of change in land cover, land use, and human population growth. The amphibian map was developed using a combination of published literature and digital databases. We used an ecoregion framework to help interpret species distributions across environmental, rather than political, boundaries. We mapped rates of land cover and use change with statistics from the World Resources Institute, refined with a global digital dataset on land cover derived from satellite data. Temporal maps of human population were developed from the World Resources Institute database and other published sources. Our resultant map of amphibian species richness illustrates that amphibians are distributed in an uneven pattern around the globe, preferring terrestrial and freshwater habitats in ecoregions that are warm and moist. Spatiotemporal patterns of human population show that, prior to the 20th century, population growth and spread was slower, most extensive in the temperate ecoregions, and largely exclusive of major regions of high amphibian richness. Since the beginning of the 20th century, human population growth has been exponential and has occurred largely in the subtropical and tropical ecoregions favored by amphibians. Population growth has been accompanied by broad-scale changes in land cover and land use, typically in support of agriculture. We merged information on land cover, land use, and human population growth to generate a composite map showing the rates at which humans have been changing the world. When compared with the map of amphibian species richness, we found that many of the regions of the

  18. The demography of Atelopus decline: Harlequin frog survival and abundance in central Panama prior to and during a disease outbreak

    OpenAIRE

    Rebecca McCaffery; Richards-Zawacki, Corinne L.; Karen R Lips

    2015-01-01

    Harlequin frogs (Bufonidae: Atelopus) are a species-rich genus of Neotropical toads that have experienced disproportionately severe population declines and extinctions caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). The genus Atelopus is of high conservation concern, but relatively little is known about the population dynamics and life history of the majority of species. We examined the demography of one population of Atelopus zeteki and two populations of A. variu...

  19. Nitrogen pollution: an assessment of its threat to amphibian survival.

    OpenAIRE

    Rouse, J D; Bishop, C A; Struger, J

    1999-01-01

    The potential for nitrate to affect amphibian survival was evaluated by examining the areas in North America where concentrations of nitrate in water occur above amphibian toxicity thresholds. Nitrogen pollution from anthropogenic sources enters bodies of water through agricultural runoff or percolation associated with nitrogen fertilization, livestock, precipitation, and effluents from industrial and human wastes. Environmental concentrations of nitrate in watersheds throughout North America...

  20. Amphibians and Reptiles from Paramakatoi and Kato, Guyana

    Science.gov (United States)

    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.

  1. Amphibian Oasis: Designing and Building a Schoolyard Pond.

    Science.gov (United States)

    Gosselin, Heather; Johnson, Bob

    1996-01-01

    Building a pond in a schoolyard is a rewarding way to help boost local populations of amphibians, to increase the natural value of school grounds, and to serve as a locale for observing the life cycles of plants, invertebrates, and amphibians. This article outlines important considerations in designing and building a pond from siting through…

  2. Partners in amphibian and reptile conservation 2013 annual report

    Science.gov (United States)

    Conrad, Paulette M., (Edited By); 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.

  3. Global Phenotype Screening and Transcript Analysis Outlines the Inhibitory Mode(s) of Action of Two Amphibian-Derived, α-Helical, Cationic Peptides on Saccharomyces cerevisiae▿ †

    OpenAIRE

    Morton, C Oliver; Hayes, Andrew; Wilson, Michael; Rash, Bharat M.; Oliver, Stephen G.; Coote, Peter

    2007-01-01

    Dermaseptin S3(1-16) [DsS3(1-16)] and magainin 2 (Mag 2) are two unrelated, amphibian-derived cationic peptides that adopt an α-helical structure within microbial membranes and have been proposed to kill target organisms via membrane disruption. Using a combination of global deletion mutant library phenotypic screening, expression profiling, and physical techniques, we have carried out a comprehensive in vitro analysis of the inhibitory action of these two peptides on the model fungus Sacchar...

  4. 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.

  5. Infection and transmission heterogeneity of a multi-host pathogen (Batrachochytrium dendrobatidis) within an amphibian community.

    Science.gov (United States)

    Fernández-Beaskoetxea, S; Bosch, J; Bielby, J

    2016-02-11

    The majority of parasites infect multiple hosts. As the outcome of the infection is different in each of them, most studies of wildlife disease focus on the few species that suffer the most severe consequences. However, the role that each host plays in the persistence and transmission of infection can be crucial to understanding the spread of a parasite and the risk it poses to the community. Current theory predicts that certain host species can modulate the infection in other species by amplifying or diluting both infection prevalence and infection intensity, both of which have implications for disease risk within those communities. The fungus Batrachochytrium dendrobatidis (Bd), the causal agent of the disease chytridiomycosis, has caused global amphibian population declines and extinctions. However, not all infected species are affected equally, and thus Bd is a good example of a multi-host pathogen that must ultimately be studied with a community approach. To test whether the common midwife toad Alytes obstetricans is a reservoir and possible amplifier of infection of other species, we used experimental approaches in captive and wild populations to determine the effect of common midwife toad larvae on infection of other amphibian species found in the Peñalara Massif, Spain. We observed that the most widely and heavily infected species, the common midwife toad, may be amplifying the infection loads in other species, all of which have different degrees of susceptibility to Bd infection. Our results have important implications for performing mitigation actions focused on potential 'amplifier' hosts and for better understanding the mechanisms of Bd transmission. PMID:26865231

  6. Ion transport by the amphibian primary ureter

    DEFF Research Database (Denmark)

    Møbjerg, Nadja

    2008-01-01

    Three kidney systems appear during vertebrate development - the pronephros, mesonephros and metanephros. A characteristic of vertebrate organogenesis is the development of a primary ureter in association with the pronephros. This duct forms the collecting duct system of the latter kidneys and it is......+] steps from 3 to 20 mmol/l and a hyperpolarization of Vm upon lowering [Na+] from 102 to 2 mmol/l, indicating the presence of luminal K+ and Na+ conductances. This study provides the first functional data on the vertebrate primary ureter. The data show that the primary ureter of axolotl larvae...... putative ion transport mechanisms in the primary ureter of the freshwater amphibian Ambystoma mexicanum (axolotl). Primary ureters isolated from axolotl larvae were perfused in vitro and single cells were impaled across the basal cell membrane with glass microelectrodes. In 42 cells the membrane potential...

  7. Parasite fitness traits under environmental variation: disentangling the roles of a chytrid's immediate host and external environment.

    Science.gov (United States)

    Van den Wyngaert, Silke; Vanholsbeeck, Olivier; Spaak, Piet; Ibelings, Bas W

    2014-10-01

    Parasite environments are heterogeneous at different levels. The first level of variability is the host itself. The second level represents the external environment for the hosts, to which parasites may be exposed during part of their life cycle. Both levels are expected to affect parasite fitness traits. We disentangle the main and interaction effects of variation in the immediate host environment, here the diatom Asterionella formosa (variables host cell volume and host condition through herbicide pre-exposure) and variation in the external environment (variables host density and acute herbicide exposure) on three fitness traits (infection success, development time and reproductive output) of a chytrid parasite. Herbicide exposure only decreased infection success in a low host density environment. This result reinforces the hypothesis that chytrid zoospores use photosynthesis-dependent chemical cues to locate its host. At high host densities, chemotaxis becomes less relevant due to increasing chance contact rates between host and parasite, thereby following the mass-action principle in epidemiology. Theoretical support for this finding is provided by an agent-based simulation model. The immediate host environment (cell volume) substantially affected parasite reproductive output and also interacted with the external herbicide exposed environment. On the contrary, changes in the immediate host environment through herbicide pre-exposure did not increase infection success, though it had subtle effects on zoospore development time and reproductive output. This study shows that both immediate host and external environment as well as their interaction have significant effects on parasite fitness. Disentangling these effects improves our understanding of the processes underlying parasite spread and disease dynamics. PMID:24863129

  8. AmphibiaChina: an online database of Chinese Amphibians

    Science.gov (United States)

    CHE, Jing; WANG, Kai

    2016-01-01

    AmphibiaChina, an open-access, web-based database, is designed to provide comprehensive and up-to-date information on Chinese amphibians. It offers an integrated module with six major sections. Compared to other known databases including AmphibiaWeb and Amphibian Species of the World, AmphibiaChina has the following new functions: (1) online species identification based on DNA barcode sequences; (2) comparisons and discussions of different major taxonomic systems; and (3) phylogenetic progress on Chinese amphibians. This database offers a window for the world to access available information of Chinese amphibians. AmphibiaChina with its Chinese version can be accessed at http://www.amphibiachina.org. PMID:26828034

  9. Metabolism of pesticides after dermal exposure to amphibians

    Science.gov (United States)

    Understanding how pesticide exposure to non-target species influences toxicity is necessary to accurately assess the ecological risks these compounds pose. Aquatic, terrestrial, and arboreal amphibians are often exposed to pesticides during their agricultural application resultin...

  10. 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 ...

  11. Twenty years of ISAREN: an amphibian biologist in Wonderland.

    Science.gov (United States)

    Kikuyama, Sakae

    2010-09-01

    The 6th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology (ISAREN), the former International Symposium on Amphibian Endocrinology (ISAE), was recently held in Berlin. ISAREN developed from two symposia on amphibian biology held in European countries in 1988-1990. In this article, the history of ISAREN was briefly stated. In addition, some of the topics of our researches carried out in collaboration with several groups, using various amphibian species during the past 20 years and/or presented in the past symposia were reviewed. The topics included the discovery of pancreatic chitinase, involvement of growth hormone in vitellogenin synthesis, changes of ANF-like immunoreactivity in the frogs sent into the space, discovery of a peptide sex-pheromone, origin of the epithelial pituitary, and hypothalamic regulation of thyroid-stimulating hormone. PMID:20138045

  12. Nationwide Abnormal Amphibian Monitoring Project : Region 3 : Interim Report 2003

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2000, the FWSs Environmental Contaminants Program currently Environmental Quality Program received funding as part of the Department of Interiors Amphibian...

  13. Nationwide Abnormal Amphibian Monitoring Project : Region 3: 2002

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2000, the FWSs Environmental Contaminants Program currently Environmental Quality Program received funding as part of the Department of Interiors Amphibian...

  14. AmphibiaChina: an online database of Chinese Amphibians.

    Science.gov (United States)

    Che, Jing; Wang, Kai

    2016-01-18

    AmphibiaChina, an open-access, web-based database, is designed to provide comprehensive and up-to-date information on Chinese amphibians. It offers an integrated module with six major sections. Compared to other known databases including AmphibiaWeb and Amphibian Species of the World, AmphibiaChina has the following new functions: (1) online species identification based on DNA barcode sequences; (2) comparisons and discussions of different major taxonomic systems; and (3) phylogenetic progress on Chinese amphibians. This database offers a window for the world to access available information of Chinese amphibians. AmphibiaChina with its Chinese version can be accessed at http://www.amphibiachina.org. PMID:26828034

  15. Invasive and introduced reptiles and amphibians: Chapter 28

    Science.gov (United States)

    Reed, Robert N.; Krysko, Kenneth L.

    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.

  16. Nationwide Abnormal Amphibian Monitoring Project : Region 3 : Interim Report 2004

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2000, the FWSs Environmental Contaminants Program currently Environmental Quality Program received funding as part of the Department of Interiors Amphibian...

  17. Declining amphibian populations: a global phenomenon in conservation biology

    Directory of Open Access Journals (Sweden)

    Gardner, T.

    2001-01-01

    Full Text Available The majority of the recent reductions in the Earth's biodiversity can be attributed to direct human impacts on the environment. An increasing number of studies over the last decade have reported declines in amphibian populations in areas of pristine habitat. Such reports suggest the role of indirect factors and a global effect of human activities on natural systems. Declines in amphibian populations bear significant implications for the functioning of many terrestrial ecosystems, and may signify important implications for human welfare. A wide range of candidates have been proposed to explain amphibian population declines. However, it seems likely that the relevance of each factor is dependent upon the habitat type and species in question, and that complex synergistic effects between a number of environmental factors is of critical importance. Monitoring of amphibian populations to assess the extent and cause of declines is confounded by a number of ecological and methodological limitations.

  18. Amphibian and Reptile Research on Coldwater National Wildlife Refuge, Mississippi

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The management actions in the wildlife ponds on Coldwater National Wildlife Refuge create a highly variable and dynamic environment for amphibians and reptiles....

  19. 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. PMID:23717602

  20. Trends in amphibian occupancy in the United States.

    Directory of Open Access Journals (Sweden)

    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.

  1. 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...

  2. 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.

  3. Abnormal amphibians on U.S. National Wildlife Refuges

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This project contains a journal article, a news release, FAQs, a fact sheet, photos, and a dataset related to a 10-year study of amphibian abnormalities on U.S....

  4. Conservation needs of amphibians in China:A review

    Institute of Scientific and Technical Information of China (English)

    Michael; Wai; Neng; LAU; Simon; N; STUART; Janice; S; CHANSON; Neil; A; COX; Debra; L; FISCHMAN

    2007-01-01

    The conservation status of all the amphibians in China is analyzed,and the country is shown to be a global priority for conservation in comparison to many other countries of the world.Three Chinese regions are particularly rich in amphibian diversity:Hengduan,Nanling,and Wuyi mountains.Sala-manders are more threatened than frogs and toads.Several smaller families show a high propensity to become seriously threatened:Bombinatoridae,Cryptobranchidae,Hynobiidae and Salamandridae.Like other parts of the world,stream-breeding,high-elevation forest amphibians have a much higher likeli-hood of being seriously threatened.Habitat loss,pollution,and over-harvesting are the most serious threats to Chinese amphibians.Over-harvesting is a less pervasive threat than habitat loss,but it is more likely to drive a species into rapid decline.Five conservation challenges are mentioned with recommendations for the highest priority research and conservation actions.

  5. AmphibiaChina: an online database of Chinese Amphibians

    OpenAIRE

    CHE, Jing; Wang, Kai

    2016-01-01

    AmphibiaChina, an open-access, web-based database, is designed to provide comprehensive and up-to-date information on Chinese amphibians. It offers an integrated module with six major sections. Compared to other known databases including AmphibiaWeb and Amphibian Species of the World, AmphibiaChina has the following new functions: (1) online species identification based on DNA barcode sequences; (2) comparisons and discussions of different major taxonomic systems; and (3) phylogenetic progres...

  6. Amphibian and reptile distribution in forests adjacent to watercourses

    OpenAIRE

    Olsson, Cecilia

    2008-01-01

    Worldwide amphibians and reptiles are declining with habitat fragmentation and destruction as the primary cause. Riparian areas are important for the herpetofauna, but as land is converted to agriculture or harvested for timber the areas are diminishing. The aim of this study was to examine amphibian and reptile abundance in relation to distance from water and in relation to habitat characteristics, foremost per cent deciduous trees. The survey was conducted during spring at six different loc...

  7. Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

    OpenAIRE

    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 w...

  8. Seasonal and ontogenetic variation of skin microbial communities and relationships to natural disease dynamics in declining amphibians.

    Science.gov (United States)

    Longo, Ana V; Savage, Anna E; Hewson, Ian; Zamudio, Kelly R

    2015-07-01

    Recently, microbiologists have focused on characterizing the probiotic role of skin bacteria for amphibians threatened by the fungal disease chytridiomycosis. However, the specific characteristics of microbial diversity required to maintain health or trigger disease are still not well understood in natural populations. We hypothesized that seasonal and developmental transitions affecting susceptibility to chytridiomycosis could also alter the stability of microbial assemblages. To test our hypothesis, we examined patterns of skin bacterial diversity in two species of declining amphibians (Lithobates yavapaiensis and Eleutherodactylus coqui) affected by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We focused on two important transitions that affect Bd susceptibility: ontogenetic (from juvenile to adult) shifts in E. coqui and seasonal (from summer to winter) shifts in L. yavapaiensis. We used a combination of community-fingerprinting analyses and 16S rRNA amplicon sequencing to quantify changes in bacterial diversity and assemblage composition between seasons and developmental stages, and to investigate the relationship between bacterial diversity and pathogen load. We found that winter-sampled frogs and juveniles, two states associated with increased Bd susceptibility, exhibited higher diversity compared with summer-sampled frogs and adult individuals. Our findings also revealed that hosts harbouring higher bacterial diversity carried lower Bd infections, providing support for the protective role of bacterial communities. Ongoing work to understand skin microbiome resilience after pathogen disturbance has the potential to identify key taxa involved in disease resistance. PMID:26587253

  9. A preliminary report of amphibian mortality patterns on railways

    Directory of Open Access Journals (Sweden)

    Karolina A. Budzik

    2014-06-01

    Full Text Available In contrast to road mortality, little is known about amphibian railroad mortality. The aim of this study was to quantify amphibian mortality along a railway line as well as to investigate the relationship between the availability of breeding sites in the surrounding habitats and the monthly variation of amphibian railway mortality. The study was conducted from April to July 2011 along 45 km of the railway line Kraków - Tarnów (Poland, Małopolska province. Three species were affected by railway mortality: Bufo bufo, Rana temporaria and Pelophylax kl. esculentus. Most dead individuals (77% were adult common toads. The largest number (14 of amphibian breeding sites was located in the most heterogeneous habitats (woodland and rural areas, which coincides with the sectors of highest amphibian mortality (42% of all accidents. As in the case of roads, spring migration is the period of highest amphibian mortality (87% of all accidents on railroads. Our findings suggest that railroad mortality depends on the agility of the species, associated primarily with the ability to overcome the rails.

  10. Baseline Population Inventory of Amphibians on the Mountain Longleaf National Wildlife Refuge and Screening for the Amphibian Disease Batrachochytrium dendrobatidis

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — From July of 2012 to June of 2013, we conducted baseline inventories for amphibians and sampled for the disease Batrachochytrium dendrobatidis on the Mountain...

  11. ITS1 copy number varies among Batrachochytrium dendrobatidis strains: implications for qPCR estimates of infection intensity from field-collected amphibian skin swabs.

    Directory of Open Access Journals (Sweden)

    Ana V Longo

    Full Text Available Genomic studies of the amphibian-killing fungus (Batrachochytrium dendrobatidis, [Bd] identified three highly divergent genetic lineages, only one of which has a global distribution. Bd strains within these linages show variable genomic content due to differential loss of heterozygosity and recombination. The current quantitative polymerase chain reaction (qPCR protocol to detect the fungus from amphibian skin swabs targets the intergenic transcribed spacer 1 (ITS1 region using a TaqMan fluorescent probe specific to Bd. We investigated the consequences of genomic differences in the quantification of ITS1 from eight distinct Bd strains, including representatives from North America, South America, the Caribbean, and Australia. To test for potential differences in amplification, we compared qPCR standards made from Bd zoospore counts for each strain, and showed that they differ significantly in amplification rates. To test potential mechanisms leading to strain differences in qPCR reaction parameters (slope and y-intercept, we: a compared standard curves from the same strains made from extracted Bd genomic DNA in equimolar solutions, b quantified the number of ITS1 copies per zoospore using a standard curve made from PCR-amplicons of the ITS1 region, and c cloned and sequenced PCR-amplified ITS1 regions from these same strains to verify the presence of the probe site in all haplotypes. We found high strain variability in ITS1 copy number, ranging from 10 to 144 copies per single zoospore. Our results indicate that genome size might explain strain differences in ITS1 copy number, but not ITS1 sequence variation because the probe-binding site and primers were conserved across all haplotypes. For standards constructed from uncharacterized Bd strains, we recommend the use of single ITS1 PCR-amplicons as the absolute standard in conjunction with current quantitative assays to inform on copy number variation and provide universal estimates of pathogen

  12. Translocations of amphibians: Proven management method or experimental technique

    Science.gov (United States)

    Seigel, Richard A.; Dodd, C. Kenneth, Jr.

    2002-01-01

    In an otherwise excellent review of metapopulation dynamics in amphibians, Marsh and Trenham (2001) make the following provocative statements (emphasis added): If isolation effects occur primarily in highly disturbed habitats, species translocations may be necessary to promote local and regional population persistence. Because most amphibians lack parental care, they areprime candidates for egg and larval translocations. Indeed, translocations have already proven successful for several species of amphibians. Where populations are severely isolated, translocations into extinct subpopulations may be the best strategy to promote regional population persistence. We take issue with these statements for a number of reasons. First, the authors fail to cite much of the relevant literature on species translocations in general and for amphibians in particular. Second, to those unfamiliar with current research in amphibian conservation biology, these comments might suggest that translocations are a proven management method. This is not the case, at least in most instances where translocations have been evaluated for an appropriate period of time. Finally, the authors fail to point out some of the negative aspects of species translocation as a management method. We realize that Marsh and Trenham's paper was not concerned primarily with translocations. However, because Marsh and Trenham (2001) made specific recommendations for conservation planners and managers (many of whom are not herpetologists or may not be familiar with the pertinent literature on amphibians), we believe that it is essential to point out that not all amphibian biologists are as comfortable with translocations as these authors appear to be. We especially urge caution about advocating potentially unproven techniques without a thorough review of available options.

  13. Social-insect fungus farming

    DEFF Research Database (Denmark)

    Aanen, Duur Kornelis; Boomsma, Jacobus Jan

    2006-01-01

    Which social insects rear their own food? Growing fungi for food has evolved twice in social insects: once in new-world ants about 50 million years ago; and once in old-world termites between 24 and 34 million years ago [1] and [2] . The termites domesticated a single fungal lineage - the extant...... basidiomycete genus Termitomyces - whereas the ants are associated with a larger diversity of fungal lineages (all basidiomycetes). The ants and termites forage for plant material to provision their fungus gardens. Their crops convert this carbon-rich plant material into nitrogen-rich fungal biomass to provide...

  14. Energy and water in aestivating amphibians.

    Science.gov (United States)

    Carvalho, José E; Navas, Carlos A; Pereira, Isabel C

    2010-01-01

    The physiological mechanisms, behavioral adjustments, and ecological associations that allow animal species to live in extreme environments have evoked the attention of many zoologists. Often, extreme environments are defined as those believed to be limiting to life in terms of water, energetic availability, and temperature. These three elements seem extreme in a number of arid and semi-arid settings that even so have been colonized by amphibians. Because this taxon is usually seen as the quintessential water-dependent ectotherm tetrapods, their presence in a number of semi-arid environments poses a number of intriguing questions regarding microhabitat choice and physiological plasticity, particularly regarding the ecological and physiological correlates of behaviors granting avoidance of the harshest conditions of semi-arid environments. Such avoidance states, generally associated to the concept of aestivation, are currently seen as a diverse and complex phenomena varying from species to species and involving numerous behavioral and metabolic adjustments that enhance survival during the drought. This chapter reviews the physiological ecology of anuran aestivation, mainly from the perspective of water and energy balance. PMID:20069408

  15. Novel Peptides from Skins of Amphibians Showed Broad-Spectrum Antimicrobial Activities.

    Science.gov (United States)

    Wang, Ying; Zhang, Yue; Lee, Wen-Hui; Yang, Xinwang; Zhang, Yun

    2016-03-01

    Peptide agents are often considered as potential biomaterials for developing new drugs that can overcome the rising resistance of pathogenic micro-organisms to classic antibiotic treatments. One key source of peptide agents is amphibian skin, as they provide a great deal of naturally occurring antimicrobial peptide (AMP) templates awaiting further exploitation and utilization. In this study, 12 novel AMPs from the skins of 3 ranid frogs, Rana limnocharis, R. exilispinosa, and Amolops afghanus, were identified using a 5' PCR primer. A total of 11 AMPs exhibited similarities with currently known AMP families, including brevinin-1, brevinin-2, esculentin-1, and nigrocin, besides, one AMP, named as Limnochariin, represented a novel AMP family. All 12 AMPs contain a C-terminus cyclic motif and most of them show obvious antimicrobial activities against 18 standard and clinically isolated strains of bacteria, including 4 Gram-positive bacteria, 11 Gram-negative bacteria, and 3 fungus. These findings provide helpful insight that will be useful in the design of anti-infective peptide agents. PMID:26452973

  16. 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.

  17. Prior infection does not improve survival against the amphibian disease Chytridiomycosis.

    Directory of Open Access Journals (Sweden)

    Scott D Cashins

    Full Text Available Many amphibians have declined globally due to introduction of the pathogenic fungus Batrachochytrium dendrobatidis (Bd. Hundreds of species, many in well-protected habitats, remain as small populations at risk of extinction. Currently the only proven conservation strategy is to maintain species in captivity to be reintroduced at a later date. However, methods to abate the disease in the wild are urgently needed so that reintroduced and wild animals can survive in the presence of Bd. Vaccination has been widely suggested as a potential strategy to improve survival. We used captive-bred offspring of critically endangered booroolong frogs (Litoria booroolongensis to test if vaccination in the form of prior infection improves survival following re exposure. We infected frogs with a local Bd isolate, cleared infection after 30 days (d using itraconazole just prior to the onset of clinical signs, and then re-exposed animals to Bd at 110 d. We found prior exposure had no effect on survival or infection intensities, clearly showing that real infections do not stimulate a protective adaptive immune response in this species. This result supports recent studies suggesting Bd may evade or suppress host immune functions. Our results suggest vaccination is unlikely to be useful in mitigating chytridiomycosis. However, survival of some individuals from all experimental groups indicates existence of protective innate immunity. Understanding and promoting this innate resistance holds potential for enabling species recovery.

  18. Prior infection does not improve survival against the amphibian disease Chytridiomycosis.

    Science.gov (United States)

    Cashins, Scott D; Grogan, Laura F; McFadden, Michael; Hunter, David; Harlow, Peter S; Berger, Lee; Skerratt, Lee F

    2013-01-01

    Many amphibians have declined globally due to introduction of the pathogenic fungus Batrachochytrium dendrobatidis (Bd). Hundreds of species, many in well-protected habitats, remain as small populations at risk of extinction. Currently the only proven conservation strategy is to maintain species in captivity to be reintroduced at a later date. However, methods to abate the disease in the wild are urgently needed so that reintroduced and wild animals can survive in the presence of Bd. Vaccination has been widely suggested as a potential strategy to improve survival. We used captive-bred offspring of critically endangered booroolong frogs (Litoria booroolongensis) to test if vaccination in the form of prior infection improves survival following re exposure. We infected frogs with a local Bd isolate, cleared infection after 30 days (d) using itraconazole just prior to the onset of clinical signs, and then re-exposed animals to Bd at 110 d. We found prior exposure had no effect on survival or infection intensities, clearly showing that real infections do not stimulate a protective adaptive immune response in this species. This result supports recent studies suggesting Bd may evade or suppress host immune functions. Our results suggest vaccination is unlikely to be useful in mitigating chytridiomycosis. However, survival of some individuals from all experimental groups indicates existence of protective innate immunity. Understanding and promoting this innate resistance holds potential for enabling species recovery. PMID:23451076

  19. [Cutaneous mold fungus granuloma from Ulocladium chartarum].

    Science.gov (United States)

    Altmeyer, P; Schon, K

    1981-01-01

    Cutaneous granulomas due to the mold fungus Ulocladium chartarum (Preuss) are described in a 58 year old woman. This fungus is usually harmless for mammalian. It is thought that a consisting immunosuppression (Brill-Symmer's disease, therapy with corticosteroids) was a priming condition for the infection. The route of infection in this patient described is unknown. PMID:7194869

  20. Wing pathology of white-nose syndrome in bats suggests life-threatening disruption of physiology

    Science.gov (United States)

    Cryan, Paul M.; Meteyer, Carol U.; Boyles, Justin G.; Blehert, David S.

    2010-01-01

    White-nose syndrome (WNS) is causing unprecedented declines in several species of North American bats. The characteristic lesions of WNS are caused by the fungus Geomyces destructans, which erodes and replaces the living skin of bats while they hibernate. It is unknown how this infection kills the bats. We review here the unique physiological importance of wings to hibernating bats in relation to the damage caused by G. destructans and propose that mortality is caused by catastrophic disruption of wing-dependent physiological functions. Mechanisms of disease associated with G. destructans seem specific to hibernating bats and are most analogous to disease caused by chytrid fungus in amphibians.

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

    Science.gov (United States)

    Welsh, H.H., Jr.; Fellers, G.M.; Lind, A.J.

    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 among terrestrial amphibians in northwestern California forests. The majority of amphibians, both species and relative numbers, in these forests are direct-developing salamanders of the family Plethodontidae. We examined amphibian richness and evenness, and the relative abundances of the four most common species of plethodontid salamanders. We examined evidence of differences between years in two ecological provinces (coastal and interior) and across young, mature, and late seral forests and with reference to a moisture gradient from xeric to hydric within late seral forests. We found evidence of declines in species richness across years on late seral mesic stands and in the coastal ecological province, but these differences appeared to be caused by differences in the detection of rarer species, rather than evidence of an overall pattern. We also found differences among specific years in numbers of individuals of the most abundant species, Ensatina eschscholtzii, but these differences also failed to reflect a consistent pattern of declines between the two decadal sample periods. Results showing differences in richness, evenness, and relative abundances along both the seral and moisture continua were consistent with previous research. Overall, we found no compelling evidence of a downward trend in terrestrial plethodontid salamanders. We believe that continued monitoring of terrestrial salamander populations is important to understanding mechanisms of population declines in amphibian species. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  2. 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.

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

    Science.gov (United States)

    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. PMID:20190117

  4. Germ Tube Mediated Invasion of Batrachochytrium dendrobatidis in Amphibian Skin Is Host Dependent

    OpenAIRE

    Van Rooij, Pascale; Martel, An; D'Herde, Katharina; Brutyn, Melanie; Croubels, Siska; Ducatelle, Richard; Haesebrouck, Freddy; Pasmans, Frank

    2012-01-01

    Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, a fungal skin disease in amphibians and driver of worldwide amphibian declines. We focussed on the early stages of infection by Bd in 3 amphibian species with a differential susceptibility to chytridiomycosis. Skin explants of Alytes muletensis, Litoria caerulea and Xenopus leavis were exposed to Bd in an Ussing chamber for 3 to 5 days. Early interactions of Bd with amphibian skin were observed using light microsc...

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

    OpenAIRE

    BROWN, DONALD J.; Garrett M. Street; Robert W. Nairn; 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...

  6. Hormonal regulation of ion and water transport in anuran amphibians.

    Science.gov (United States)

    Uchiyama, Minoru; Konno, Norifumi

    2006-05-15

    Amphibians occupy a wide variety of ecological habitats, and their adaptation is made possible through the specialization of the epithelia of their osmoregulatory organs, such as the skin, kidney, and urinary bladder, which control the hydromineral and acid-base balance of their internal medium. Amphibians can change drastically plasma Na+, Cl-, and urea levels and excretion rates in response to environmental stimuli such as acute desiccation and changes in external salinity. Several hormones and the autonomic nervous system act to control osmoregulation. Several ion channels including an epithelial sodium channel (ENaC), a urea transporter (UT), and water channels (AQPs) are found in epithelial tissues of their osmoregulatory organs. This mini review examines the currents status of our knowledge about hormone receptors for arginine vasotocin, angiotensin II and aldosterone, and membrane ion channels and transporters, such as ENaC, UT, and AQPs in amphibians. PMID:16472810

  7. Spatial network structure and amphibian persistence in stochastic environments

    Science.gov (United States)

    Fortuna, Miguel A; Gómez-Rodríguez, Carola; Bascompte, Jordi

    2006-01-01

    In the past few years, the framework of complex networks has provided new insight into the organization and function of biological systems. However, in spite of its potential, spatial ecology has not yet fully incorporated tools and concepts from network theory. In the present study, we identify a large spatial network of temporary ponds, which are used as breeding sites by several amphibian species. We investigate how the structural properties of the spatial network change as a function of the amphibian dispersal distance and the hydric conditions. Our measures of network topology suggest that the observed spatial structure of ponds is robust to drought (compared with similar random structures), allowing the movement of amphibians to and between flooded ponds, and hence, increasing the probability of reproduction even in dry seasons. PMID:16777733

  8. Amphibians of the Simbruini Mountains (Latium, Central Italy

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. Ontogenetic pattern change in amphibians: the case of Salamandra corsica

    Directory of Open Access Journals (Sweden)

    Wouter Beukema

    2011-12-01

    Full Text Available Ontogenetic, post-metamorphic pattern development is a rarely studied topic in amphibian science. As there are indications that the pattern of Salamandra corsica might expand over time, digital image analyses were applied in order to measure several phenotypical variables which were related to the snout vent length. Results show a significant increase of patches which change to irregular shapes while SVL increases. Digital image analysis is identified as a suitable tool to explore pattern shape and change in general, while the documented pattern development in S. corsica might be one of the first quantified cases of post-metamorphic ontogenetic pattern change in amphibians.

  11. 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. PMID:19265581

  12. Equilibrium of global amphibian species distributions with climate

    DEFF Research Database (Denmark)

    Munguí­a, Mariana; Rahbek, Carsten; Rangel, Thiago F.; Diniz-Filho, Jose Alexandre F.; Bastos Araujo, Miguel

    2012-01-01

    not be at equilibrium with contemporary climate. On average, amphibians occupied 30% to 57% of their potential distributions. Although patterns differed across regions, there were no significant differences among lineages. Species in the Neotropic, Afrotropics, Indo-Malay, and Palaearctic occupied a...... complete lineage across its entire distribution. We measure departures of equilibrium with contemporary climate for the distributions of the world amphibian species. Specifically, we fitted bioclimatic envelopes for 5544 species using three presence-only models. We then measured the proportion of the...

  13. Microsatellite primers for fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Gertsch, P J; Boomsma, JJ

    2002-01-01

    developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants.......We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...

  14. Microsatellite Primers for Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

    2002-01-01

    developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants.......We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...

  15. Slow dynamics of the amphibian tympanic membrane

    Science.gov (United States)

    Bergevin, Christopher; Meenderink, Sebastiaan W. F.; van der Heijden, Marcel; Narins, Peter M.

    2015-12-01

    Several studies have demonstrated that delays associated with evoked otoacoustic emissions (OAEs) largely originate from filter delays of resonant elements in the inner ear. However, one vertebrate group is an exception: Anuran (frogs and toads) amphibian OAEs exhibit relatively long delays (several milliseconds), yet relatively broad tuning. These delays, also apparent in auditory nerve fiber (ANF) responses, have been partially attributed to the middle ear (ME), with a total forward delay of ˜0.7 ms (˜30 times longer than in gerbil). However, ME forward delays only partially account for the longer delays of OAEs and ANF responses. We used scanning laser Doppler vibrometery to map surface velocity over the tympanic membrane (TyM) of anesthetized bullfrogs (Rana catesbeiana). Our main finding is a circularly-symmetric wave on the TyM surface, starting at the outer edges of the TyM and propagating inward towards the center (the site of the ossicular attachment). This wave exists for frequencies ˜0.75-3 kHz, overlapping the range of bullfrog hearing (˜0.05-1.7 kHz). Group delays associated with this wave varied from 0.4 to 1.2 ms and correlated with with TyM diameter, which ranged from ˜6-16 mm. These delays correspond well to those from previous ME measurements. Presumably the TyM waves stem from biomechanical constraints of semi-aquatic species with a relatively large tympanum. We investigated some of these constraints by measuring the pressure ratio across the TyM (˜10-30 dB drop, delay of ˜0.35 ms), the effects of ossicular interruption, the changes due to physiological state of TyM (`dry-out'), and by calculating the middle-ear input impedance. In summary, we found a slow, inward-traveling wave on the TyM surface that accounts for a substantial fraction of the relatively long otoacoustic and neurophysiological delays previously observed in the anuran inner ear.

  16. A new macrocyclic trichochecene from soil fungus

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From fermentation broth of soil fungus 254-2 obtained from Yunnan province,a new macrocylic trichochecene was isolated.The structure was determined on the basis of spectroscopic evidences especially the 2-D NMR spectra.

  17. Factors contributing to amphibian road mortality in a wetland

    Directory of Open Access Journals (Sweden)

    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].

  18. Salmonella Infections Caused by Reptiles and Amphibians in Childcare Centers

    Centers for Disease Control (CDC) Podcasts

    2013-02-07

    Dr. Neil Vora, an EIS Officer at CDC, discusses his article about Salmonella infections in childcare centers caused by reptiles and amphibians.  Created: 2/7/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/7/2013.

  19. Examining the evidence for chytridiomycosis in threatened amphibian species.

    Directory of Open Access Journals (Sweden)

    Matthew Heard

    Full Text Available Extinction risks are increasing for amphibians due to rising threats and minimal conservation efforts. Nearly one quarter of all threatened/extinct amphibians in the IUCN Red List is purportedly at risk from the disease chytridiomycosis. However, a closer look at the data reveals that Batrachochytrium dendrobatidis (the causal agent has been identified and confirmed to cause clinical disease in only 14% of these species. Primary literature surveys confirm these findings; ruling out major discrepancies between Red List assessments and real-time science. Despite widespread interest in chytridiomycosis, little progress has been made between assessment years to acquire evidence for the role of chytridiomycosis in species-specific amphibian declines. Instead, assessment teams invoke the precautionary principle when listing chytridiomycosis as a threat. Precaution is valuable when dealing with the world's most threatened taxa, however scientific research is needed to distinguish between real and predicted threats in order to better prioritize conservation efforts. Fast paced, cost effective, in situ research to confirm or rule out chytridiomycosis in species currently hypothesized to be threatened by the disease would be a step in the right direction. Ultimately, determining the manner in which amphibian conservation resources are utilized is a conversation for the greater conservation community that we hope to stimulate here.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Rayleigh instability of the inverted one-cell amphibian embryo

    NARCIS (Netherlands)

    Nouri, Comron; Luppes, Roel; Veldman, Arthur E.P.; Tuszynski, Jack A.; Gordon, Richard

    2008-01-01

    The one-cell amphibian embryo is modeled as a rigid spherical shell containing equal volumes of two immiscible fluids with different densities and viscosities and a surface tension between them. The fluids represent denser yolk in the bottom hemisphere and clearer cytoplasm and the germinal vesicle

  2. 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…

  3. Preliminary checklist of amphibians and reptiles from Baramita, Guyana

    Science.gov (United States)

    Reynolds, R.P.; MacCulloch, R.D.

    2012-01-01

    We provide an initial checklist of the herpetofauna of Baramita, a lowland rainforest site in the Northwest Region of Guyana. Twenty-five amphibian and 28 reptile species were collected during two separate dry-season visits. New country records for two species of snakes are documented, contributing to the knowledge on the incompletely known herpetofauna of Guyana.

  4. Factors contributing to amphibian road mortality in a wetland

    Institute of Scientific and Technical Information of China (English)

    Haijun GU; Qiang DAI; Qian WANG; Yuezhao WANG

    2011-01-01

    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].

  5. Emerging contaminants and their potential effects on amphibians and reptiles

    Science.gov (United States)

    Serious threats to the health and sustainability of global amphibian populations have been well documented over the last few decades. Encroachment upon and destruction of primary habitat is the most critical threat, but some species have disappeared while their habitat remains. Additional stressor...

  6. Effects of terrestrial buffer zones on amphibians on golf courses.

    Directory of Open Access Journals (Sweden)

    Holly J Puglis

    Full Text Available 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.

  7. Toxicity of road salt to Nova Scotia amphibians

    International Nuclear Information System (INIS)

    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 (LC50) 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

  8. Climate change and amphibian diversity patterns in Mexico

    DEFF Research Database (Denmark)

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

    2012-01-01

    of presence and dispersal capability) in the modelling processes. We simulated the base line (2000) and future scenarios for Mexican amphibian diversity (2020, 2050, 2080), using climate data layers constructed for Mexico. Using moving-window analyses of different sizes (9, 25, 100, 225 and 400 km2) we...

  9. Road ecology and Neotropical amphibians: contributions for future studies

    Directory of Open Access Journals (Sweden)

    Paula Eveline Ribeiro D'Anunciação

    2013-12-01

    Full Text Available Many species of amphibians have suffered serious population declines. Several factors contribute separately or jointly to these declines. However, the reduction of an available habitat due to human expansion is still the main cause, and roads are a major mean for this expansion. Both the construction phase and the subsequent use of roads have negative consequences for amphibians. We reviewed the literature on the subject within the Neotropical context. To this end, the paper begins with a summary of recent reviews and proceeds through an analysis of sampling methods used in roadkill studies, mitigation measures and the Neotropical scenario and concludes with several suggestions to guide future studies. More attention will be given to roadkills, which is one of the primary impacts on wildlife that is caused by roads. Even in the Neotropical zone most studies are foot-based, the richness and abundance of amphibians affected are higher in regions outside the Neotropics. One possible explanation is that in the other regions, the proportion of studies exclusively on amphibians is bigger. Regarding mitigation measures, most studies only indicates what should be used, but do not implement or evaluate their effectiveness.

  10. 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

  11. Projected climate impacts for the amphibians of the western hemisphere

    Science.gov (United States)

    Lawler, Joshua J.; Shafer, Sarah L.; Bancroft, Betsy A.; Blaustein, Andrew R.

    2010-01-01

    Given their physiological requirements, limited dispersal abilities, and hydrologically sensitive habitats, amphibians are likely to be highly sensitive to future climatic changes. We used three approaches to map areas in the western hemisphere where amphibians are particularly likely to be affected by climate change. First, we used bioclimatic models to project potential climate-driven shifts in the distribution of 413 amphibian species based on 20 climate simulations for 2071–2100. We summarized these projections to produce estimates of species turnover. Second, we mapped the distribution of 1099 species with restricted geographic ranges. Finally, using the 20 future climate-change simulations, we mapped areas that were consistently projected to receive less seasonal precipitation in the coming century and thus were likely to have altered microclimates and local hydrologies. Species turnover was projected to be highest in the Andes Mountains and parts of Central America and Mexico, where, on average, turnover rates exceeded 60% under the lower of two emissions scenarios. Many of the restricted-range species not included in our range-shift analyses were concentrated in parts of the Andes and Central America and in Brazil's Atlantic Forest. Much of Central America, southwestern North America, and parts of South America were consistently projected to experience decreased precipitation by the end of the century. Combining the results of the three analyses highlighted several areas in which amphibians are likely to be significantly affected by climate change for multiple reasons. Portions of southern Central America were simultaneously projected to experience high species turnover, have many additional restricted-range species, and were consistently projected to receive less precipitation. Together, our three analyses form one potential assessment of the geographic vulnerability of amphibians to climate change and as such provide broad-scale guidance for directing

  12. Inventory of amphibians and reptiles at Death Valley National Park

    Science.gov (United States)

    Persons, Trevor B.; Nowak, Erika M.

    2006-01-01

    As part of the National Park Service Inventory and Monitoring Program in the Mojave Network, we conducted an inventory of amphibians and reptiles at Death Valley National Park in 2002-04. Objectives for this inventory were to: 1) Inventory and document the occurrence of reptile and amphibian species occurring at DEVA, primarily within priority sampling areas, with the goal of documenting at least 90% of the species present; 2) document (through collection or museum specimen and literature review) one voucher specimen for each species identified; 3) provide a GIS-referenced list of sensitive species that are federally or state listed, rare, or worthy of special consideration that occur within priority sampling locations; 4) describe park-wide distribution of federally- or state-listed, rare, or special concern species; 5) enter all species data into the National Park Service NPSpecies database; and 6) provide all deliverables as outlined in the Mojave Network Biological Inventory Study Plan. Methods included daytime and nighttime visual encounter surveys, road driving, and pitfall trapping. Survey effort was concentrated in predetermined priority sampling areas, as well as in areas with a high potential for detecting undocumented species. We recorded 37 species during our surveys, including two species new to the park. During literature review and museum specimen database searches, we recorded three additional species from DEVA, elevating the documented species list to 40 (four amphibians and 36 reptiles). Based on our surveys, as well as literature and museum specimen review, we estimate an overall inventory completeness of 92% for Death Valley and an inventory completeness of 73% for amphibians and 95% for reptiles. Key Words: Amphibians, reptiles, Death Valley National Park, Inyo County, San Bernardino County, Esmeralda County, Nye County, California, Nevada, Mojave Desert, Great Basin Desert, inventory, NPSpecies.

  13. Development of a mobile application for amphibian species recognition

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. Spemann's organizer and self-regulation in amphibian embryos

    OpenAIRE

    De Robertis, Edward M

    2006-01-01

    In 1924, Spemann and Mangold demonstrated the induction of Siamese twins in transplantation experiments with salamander eggs. Recent work in amphibian embryos has followed their lead and uncovered that cells in signalling centres that are located at the dorsal and ventral poles of the gastrula embryo communicate with each other through a network of secreted growth-factor antagonists, a protease that degrades them, a protease inhibitor and bone-morphogenic-protein signals.

  16. Spemann's organizer and self-regulation in amphibian embryos.

    Science.gov (United States)

    De Robertis, Edward M

    2006-04-01

    In 1924, Spemann and Mangold demonstrated the induction of Siamese twins in transplantation experiments with salamander eggs. Recent work in amphibian embryos has followed their lead and uncovered that cells in signalling centres that are located at the dorsal and ventral poles of the gastrula embryo communicate with each other through a network of secreted growth-factor antagonists, a protease that degrades them, a protease inhibitor and bone-morphogenic-protein signals. PMID:16482093

  17. Control of respiration in fish, amphibians and reptiles

    OpenAIRE

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

    2010-01-01

    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 d...

  18. Negative Binomial GAM and GAMM to Analyse Amphibian Roadkills

    OpenAIRE

    Zuur, Alain; Mira, António; Carvalho, Filipe; Ieno, Elena; Saveliev, A.A.; Smith, G.M.; Walker, N. J.

    2009-01-01

    This chapter analyses amphibian fatalities along a road in Portugal. The data are counts of kills making a Gaussian distribution unlikely; restricting our choice of techniques. We began with generalised linear models (GLM) and generalised addi- tive models (GAM) with a Poisson distribution, but these models were overdis- persed. To solve this, you can either apply a quasi-Poisson GLM or GAM, or use the negative binomial distribution (Chapter 9). In this particular example, eith...

  19. Parallels in Amphibian and Bat Declines from Pathogenic Fungi

    OpenAIRE

    Eskew, Evan A.; Todd, Brian D.

    2013-01-01

    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 ...

  20. Evolution of erythrocyte morphology in amphibians (Amphibia: Anura)

    OpenAIRE

    Jie Wei; Yan-Yan Li; Li Wei; Guo-Hua Ding; Xiao-Li Fan; Zhi-Hua Lin

    2015-01-01

    ABSTRACT We compared the morphology of the erythrocytes of five anurans, two toad species - Bufo gargarizans (Cantor, 1842) and Duttaphrynus melanostictus (Schneider, 1799) and three frog species - Fejervarya limnocharis (Gravenhorst, 1829), Microhyla ornata (Duméril & Bibron, 1841), and Rana zhenhaiensis (Ye, Fei & Matsui, 1995). We then reconstructed the ancestral state of erythrocyte size (ES) and nuclear size (NS) in amphibians based on a molecular tree. Nine morphological traits of eryth...

  1. Reptiles and amphibians of the Savannah River Plant

    International Nuclear Information System (INIS)

    Taxonomic, distributional, and ecological information on the reptiles and amphibians of the Savannah River Plant (SRP) is provided. The purpose of such a presentation is to give a professional biologist an initial familiarity with herpetology on the SRP, and to provide sufficient comprehensive information to an ecologist, regardless of his experience in herpetology, to permit him to undertake studies that in some manner incorporate the herpetofauna of the SRP

  2. Reptiles and amphibians of the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Gibbons, J.W.; Patterson, K.K.

    1978-11-01

    Taxonomic, distributional, and ecological information on the reptiles and amphibians of the Savannah River Plant (SRP) is provided. The purpose of such a presentation is to give a professional biologist an initial familiarity with herpetology on the SRP, and to provide sufficient comprehensive information to an ecologist, regardless of his experience in herpetology, to permit him to undertake studies that in some manner incorporate the herpetofauna of the SRP. (ERB)

  3. Local adaptation of an anuran amphibian to osmotically stressful environments

    OpenAIRE

    Gómez-Mestre, Iván; Tejedo, Miguel

    2003-01-01

    Water salinity is an intense physiological stress for amphibians. However, some species, such as Bufo calamita, breed in both brackish and freshwater environments. Because selection under environmentally stressful conditions can promote local adaptation of populations, we examined the existence of geographic variation in water salinity tolerance among B. calamita populations from either fresh or brackish water ponds in Southern Spain. Comparisons were made throughout various ontogenetic stage...

  4. Spatial network structure and amphibian persistence in stochastic environments

    OpenAIRE

    Fortuna, Miguel A.; Gómez-Rodríguez, Carola; Bascompte, Jordi

    2006-01-01

    In the past few years, the framework of complex networks has provided new insight into the organization and function of biological systems. However, in spite of its potential, spatial ecology has not yet fully incorporated tools and concepts from network theory. In the present study, we identify a large spatial network of temporary ponds, which are used as breeding sites by several amphibian species. We investigate how the structural properties of the spatial network...

  5. Special Issue: Viruses Infecting Fish, Amphibians, and Reptiles

    OpenAIRE

    Gregory Chinchar, V.

    2011-01-01

    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...

  6. Nomenclatural notes on living and fossil amphibians

    Directory of Open Access Journals (Sweden)

    Martín, C.

    2012-06-01

    Full Text Available A review of extinct and living amphibians known from fossils (Allocaudata, Anura and Caudata has revealed several cases that require nomenclatural changes in order to stabilize the taxonomy of the group. Nomenclatural changes include homonym replacements, corrections of spelling variants and authorships, name availabilities, and in particular, the proposal of new combinations. These changes will allow the incorporation of some palaeontological taxa to the current evolutionary models of relationship of modern forms based on molecular phylogenies. Rana cadurcorum for Rana plicata Filhol, 1877, Rana auscitana for Rana pygmaea Lartet, 1851, and Rana sendoa for Rana robusta Brunner, 1956. Anchylorana Taylor, 1942 is considered a new synonym of Lithobates Fitzinger, 1843. New combinations proposed are: Anaxyrus defensor for Bufo defensor Meylan, 2005; Anaxyrus hibbardi for Bufo hibbardi Taylor, 1937; Anaxyrus pliocompactilis for Bufo pliocompactilis Wilson, 1968; Anaxyrus repentinus for Bufo repentinus Tihen, 1962; Anaxyrus rexroadensis for Bufo rexroadensis Tihen, 1962; Anaxyrus spongifrons for Bufo spongifrons Tihen, 1962; Anaxyrus suspectus for Bufo suspectus Tihen, 1962; Anaxyrus tiheni for Bufo tiheni Auffenberg, 1957; Anaxyrus valentinensis for Bufo valentinensis Estes et Tihen, 1964; Ichthyosaura wintershofi for Triturus wintershofi Lunau, 1950; Incilius praevius for Bufo praevius Tihen, 1951; Lithobates bucella for Rana bucella Holman, 1965; Lithobates dubitus for Anchylorana dubita Taylor, 1942; Lithobates fayeae for Rana fayeae Taylor, 1942; Lithobates miocenicus for Rana miocenica Holman, 1965; Lithobates moorei for Anchylorana moorei Taylor, 1942; Lithobates parvissimus for Rana parvissima

  7. Batrachochytrium dendrobatidis in amphibians from the Po River Delta, Northern Italy

    OpenAIRE

    Gentile Francesco Ficetola; Alice Valentini; Claude Miaud; Andrea Noferini; Stefano Mazzotti; Tony Dejean

    2011-01-01

    Batrachochytrium dendrobatidis is a pathogen infecting amphibians at the global scale and causing their decline, but knowledge of the distribution of this pathogen is far from complete. We sampled amphibians from three species (Hyla intermedia, Rana dalmatina and Pelophylax synklepton esculentus) to evaluate whether B. dendrobatidis infects amphibians in the Po River Delta Natural Park, Northern Italy. We detected the pathogen in one population of P. sk. esculentus (prevalence: 0.33). These f...

  8. Dynamic stability of communities of amphibians in short-term-flooded forest ecosystems

    OpenAIRE

    O. V. Zhukov; N. L. Gubanova

    2015-01-01

    The estimation of stability of amphibian populations on the basis of data of population dynamics is given. The paper shows an attempt to estimate the direction of dynamic changes of amphibian populations, and defines the rate of the system deviation from the stationary state due to possible influence of the environmental factors by using concepts such as reactivity, degree of reactivity and flexibility of the system when using their indexes. It is found that populations of amphibians are quit...

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

    OpenAIRE

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

    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 stud...

  10. Thermal Tolerance and Sensitivity of Amphibian Larvae from Paleartic and Neotropical Communities

    OpenAIRE

    Katzenberger, Marco

    2013-01-01

    Amphibians across the world are threatened by climate change. This work deals with the analysis of thermal tolerance and sensitivity and their latitudinal variation at the community level, with the intent of examining the prediction that tropical amphibians are at higher risk of extinction due to global warming than temperate species since their environmental temperatures are closer to their upper thermal limits. To test this prediction, two larval amphibian communities were sele...

  11. Synergistic effects of the invasive Chinese tallow (Triadica sebifera) and climate change on aquatic amphibian survival

    OpenAIRE

    Saenz, Daniel; Fucik, Erin M; Kwiatkowski, Matthew A

    2013-01-01

    Changes in climate and the introduction of invasive species are two major stressors to amphibians, although little is known about the interaction between these two factors with regard to impacts on amphibians. We focused our study on an invasive tree species, the Chinese tallow (Triadica sebifera), that annually sheds its leaves and produces leaf litter that is known to negatively impact aquatic amphibian survival. The purpose of our research was to determine whether the timing of leaf fall f...

  12. Pronephric duct extension in amphibian embryos: migration and other mechanisms.

    Science.gov (United States)

    Drawbridge, Julie; Meighan, Christopher M; Lumpkins, Rebecca; Kite, Mary E

    2003-01-01

    Initiation of excretory system development in all vertebrates requires (1) delamination of the pronephric and pronephric duct rudiments from intermediate mesoderm at the ventral border of anterior somites, and (2) extension of the pronephric duct to the cloaca. Pronephric duct extension is the central event in nephric system development; the pronephric duct differentiates into the tubule that carries nephric filtrate out of the body and induces terminal differentiation of adult kidneys. Early studies concluded that pronephric ducts formed by means of in situ segregation of pronephric duct tissue from lateral mesoderm ventral to the forming somites; more recent studies highlight caudal migration of the pronephric duct as the major morphogenetic mechanism. The purpose of this review is to provide the historical background on studies of the mechanisms of amphibian pronephric duct extension, to review evidence showing that different amphibians perform pronephric duct morphogenesis in different ways, and to suggest future studies that may help illuminate the molecular basis of the mechanisms that have evolved in amphibians to extend the pronephric duct to the cloaca. PMID:12508219

  13. AMPHIBIAN BIODIVERSITY RECOVERY IN A LARGE-SCALE ECOSYSTEM RESTORATION

    Directory of Open Access Journals (Sweden)

    ROBERT BRODMAN

    2006-12-01

    Full Text Available Abstract.—Amphibians are important components of ecosystem function and processes; however, many populations havedeclined due to habitat loss, fragmentation and degradation. We studied the effect of wetlands ecosystem restoration onamphibian population recovery at Kankakee Sands in northwest Indiana, USA. We also tested predictions about colonizationin relation to proximity to existing nature preserves and species characteristics. Prior to restoration activities (1998, theamphibian community at Kankakee Sands consisted of fourteen populations of seven species at seven breeding sites. By 2001,this community increased to 60 populations at 26 sites; however, species richness had not increased. By 2002 the communityincreased to 143 populations of eight species at 38 sites, and by 2003 there were 172 populations of ten species at 44 sites.Abundance index values increased 15-fold from 1998-2003. These increases best fit the exponential growth model. Althoughsurvival through metamorphosis was substantial during wetter than average years (2002 and 2003, during other yearsrestored wetlands dried before larvae of most species transformed. Amphibian colonization was greatest near a naturepreserve with the greatest amphibian diversity. The earliest colonists included fossorial species and those species whose habitatincludes wet and mesic sand prairie. However, the fossorial Tiger Salamander (Ambystoma tigrinum was the last species tocolonize Kankakee Sands.

  14. Nuclear flow in a filamentous fungus

    CERN Document Server

    Hickey, Patrick C; Read, Nick; Glass, N Louise; Roper, Marcus

    2012-01-01

    The syncytial cells of a filamentous fungus consist of a mass of growing, tube-like hyphae. Each extending tip is fed by a continuous flow of nuclei from the colony interior, pushed by a gradient in turgor pressure. The myco-fluidic flows of nuclei are complex and multidirectional, like traffic in a city. We map out the flows in a strain of the model filamentous fungus {\\it N. crassa} that has been transformed so that nuclei express either hH1-dsRed (a red fluorescent nuclear protein) or hH1-GFP (a green-fluorescent protein) and report our results in a fluid dynamics video.

  15. Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

    DEFF Research Database (Denmark)

    Oh, Dong-Chan; Poulsen, Michael; Currie, Cameron R; Clardy, Jon

    2009-01-01

    Fungus-growing ants engage in mutualistic associations with both the fungus they cultivate for food and actinobacteria (Pseudonocardia spp.) that produce selective antibiotics to defend that fungus from specialized fungal parasites. We have analyzed one such system at the molecular level and found...... that the bacterium associated with the ant Apterostigma dentigerum produces dentigerumycin, a cyclic depsipeptide with highly modified amino acids, to selectively inhibit the associated parasitic fungus (Escovopsis sp.)....

  16. Amphibians and disease: Implications for conservation in the Greater Yellowstone Ecosystem

    Science.gov (United States)

    Corn, P.S.

    2007-01-01

    The decline of amphibian populations is a world-wide phenomenon that has received increasing attention since about 1990. In 2004, the World Conservation Union’s global amphibian assessment concluded that 48% of the world’s 5,743 described amphibian species were in decline, with 32% considered threatened (Stuart et al. 2004). Amphibian declines are a significant issue in the western United States, where all native species of frogs in the genus Rana and many toads in the genus Bufo are at risk, particularly those that inhabit mountainous areas (Corn 2003a,b; Bradford 2005).

  17. Batrachochytrium dendrobatidis in amphibians from the Po River Delta, Northern Italy

    Directory of Open Access Journals (Sweden)

    Gentile Francesco Ficetola

    2011-12-01

    Full Text Available Batrachochytrium dendrobatidis is a pathogen infecting amphibians at the global scale and causing their decline, but knowledge of the distribution of this pathogen is far from complete. We sampled amphibians from three species (Hyla intermedia, Rana dalmatina and Pelophylax synklepton esculentus to evaluate whether B. dendrobatidis infects amphibians in the Po River Delta Natural Park, Northern Italy. We detected the pathogen in one population of P. sk. esculentus (prevalence: 0.33. These findings expand the known distribution of B. dendrobatidis in Italy and add further concern to the conservation of amphibians in this area.

  18. Open-Ended Experimentation with the Fungus Pilobolus.

    Science.gov (United States)

    Coble, Charles R.; Bland, Charles E.

    This paper describes open-ended experimentation with the fungus Pilobolus for laboratory work by high school students. The fungus structure and reproduction is described and sources of the fungus are suggested. Four areas for investigation are suggested: the effect of a diffuse light source, the effect of a point light source, the effect of light…

  19. Detection of spring viraemia of carp virus in imported amphibians reveals an unanticipated foreign animal disease threat.

    Science.gov (United States)

    Ip, Hon S; Lorch, Jeffrey M; Blehert, David S

    2016-01-01

    Global translocation of plants and animals is a well-recognized mechanism for introduction of pathogens into new regions. To mitigate this risk, various tools such as preshipment health certificates, quarantines, screening for specific disease agents and outright bans have been implemented. However, such measures only target known infectious agents and their hosts and may fail to prevent translocation of even well-recognized pathogens if they are carried by novel host species. In a recent example, we screened an imported shipment of Chinese firebelly newts (Cynops orientalis) for Batrachochytrium salamandrivorans, an emergent fungal pathogen of salamanders. All animals tested negative for the fungus. However, a virus was cultured from internal organs from 7 of the 11 individual dead salamanders and from two pools of tissues from four additional dead animals. Sequencing of a portion of the glycoprotein gene from all viral isolates indicated 100% identity and that they were most closely related to spring viraemia of carp virus (SVCV). Subsequently, SVCV-specific PCR testing indicated the presence of virus in internal organs from each of the four animals previously pooled, and whole-genome sequencing of one of the viral isolates confirmed genomic arrangement characteristic of SVCV. SVCV is a rhabdovirus pathogen of cyprinid fish that is listed as notifiable to the Office International des Epizooties. This discovery reveals a novel route for potential spillover of this economically important pathogen as rhabdovirus has not previously been documented in amphibians. PMID:27599472

  20. Death from Fungus in the Soil

    Centers for Disease Control (CDC) Podcasts

    2012-12-17

    Dr. Shira Shafir, Assistant Professor of Epidemiology at the UCLA Fielding School of Public Health, discusses her study about fungus found in soil.  Created: 12/17/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 12/18/2012.

  1. Spread of Rare Fungus from Vancouver Island

    Centers for Disease Control (CDC) Podcasts

    2006-12-20

    Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism.  Created: 12/20/2006 by Emerging Infectious Diseases.   Date Released: 12/29/2006.

  2. North Cascades National Park Service Complex Natural Resource Preservation Program Amphibian Inventory Big Beaver Watershed 1996 - Progress Report

    Data.gov (United States)

    Oak Ridge National Laboratory — The 1996 amphibian inventory in North Cascades National Park Service Complex Big Beaver watershed is part of a four year program to inventory amphibians in Pacific...

  3. Exotic Fish in Exotic Plantations: A Multi-Scale Approach to Understand Amphibian Occurrence in the Mediterranean Region

    OpenAIRE

    Cruz, Joana; Sarmento, Pedro; Carretero, Miguel A.; White, Piran C. L.

    2015-01-01

    Globally, amphibian populations are threatened by a diverse range of factors including habitat destruction and alteration. Forestry practices have been linked with low diversity and abundance of amphibians. The effect of exotic Eucalyptus spp. plantations on amphibian communities has been studied in a number of biodiversity hotspots, but little is known of its impact in the Mediterranean region. Here, we identify the environmental factors influencing the presence of six species of amphibians ...

  4. 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…

  5. The distribution of Reptiles and amphibians in the Annapurna-Dhaulagiri region (Nepal)

    OpenAIRE

    Nanhoe, L.M.R.; Ouboter, P.E.

    1987-01-01

    The reptiles and amphibians of the Annapurna-Dhaulagiri region in Nepal are keyed and described. Their distribution is recorded, based on both personal observations and literature data. The ecology of the species is discussed. The zoogeography and the altitudinal distribution are analysed. All in all 32 species-group taxa of reptiles and 21 species-group taxa of amphibians are treated.

  6. Pond preference by amphibians (Amphibia) on the Karst Plateau and in Slovenian Istria:

    OpenAIRE

    Francé, Janja

    2002-01-01

    Some habitat determinants and related presence of amphibians in 7 karst ponds in Slovenian Istria and 10 ponds on the Karst Plateau were surveyed from Marchto August 1999. The presence of different species of amphibians was established by sampling according to standard methods for amphibiand...

  7. Influence of Physiological Stress on Nutrient Stoichiometry in Larval Amphibians.

    Science.gov (United States)

    Kirschman, Lucas J; Haslett, Savhannah; Fritz, Kelley A; Whiles, Matt R; Warne, Robin W

    2016-01-01

    Exposure to environmental stressors alters animal phenotypes as well as nutrient metabolism, assimilation, and excretion. While stress-induced shifts in nutrient processes are known to alter organismal carbon (C) and nitrogen (N) stoichiometry, there has been little exploration of how environmental factors influence phosphorous (P). A better understanding of how P cycling varies with animal physiological state may provide insight into across-scale processes, because P is essential to animal function and ecological processes such as production and decomposition. We tested the effects of predator stress and exogenous glucocorticoids on C∶N∶P stoichiometry of larval amphibians. Glucocorticoids altered nutrient stoichiometry, apparently by modulating ossification and renal function. This reduced whole-body P and significantly increased N∶P. Additionally, elevated glucocorticoids caused a long-term reduction in P excretion. This reduction may reflect an initial unmeasured loss of P that glucocorticoids induce over acute timescales. In contrast, exposure to predator cues had no effect on larval C∶N∶P stoichiometry, which highlights that different stressors have varied effects on the endocrine stress response. Predation, in particular, is ubiquitous in the environment; thus, larvae responding to predators have conserved mechanisms that likely prevent or minimize physiological disruption. These results demonstrate the differing physiological roles of N and P, distinct nutrient demands associated with amphibian metamorphosis, and the contrasting effects that different environmental factors have on the physiological stress response. Our results also suggest that anthropogenic changes to the environment that induce chronic stress in amphibians could affect the biogeochemistry of nutrient-poor environments where they may act as keystone species. PMID:27327181

  8. Inhibition of Escherichia coli ATP synthase by amphibian antimicrobial peptides.

    Science.gov (United States)

    Laughlin, Thomas F; Ahmad, Zulfiqar

    2010-04-01

    Previously melittin, the alpha-helical basic honey bee venom peptide, was shown to inhibit F(1)-ATPase by binding at the beta-subunit DELSEED motif of F(1)F(o)-ATP synthase. Herein, we present the inhibitory effects of the basic alpha-helical amphibian antimicrobial peptides, ascaphin-8, aurein 2.2, aurein 2.3, carein 1.8, carein 1.9, citropin 1.1, dermaseptin, maculatin 1.1, maganin II, MRP, or XT-7, on purified F(1) and membrane bound F(1)F(0)Escherichia coli ATP synthase. We found that the extent of inhibition by amphibian peptides is variable. Whereas MRP-amide inhibited ATPase essentially completely (approximately 96% inhibition), carein 1.8 did not inhibit at all (0% inhibition). Inhibition by other peptides was partial with a range of approximately 13-70%. MRP-amide was also the most potent inhibitor on molar scale (IC(50) approximately 3.25 microM). Presence of an amide group at the c-terminal of peptides was found to be critical in exerting potent inhibition of ATP synthase ( approximately 20-40% additional inhibition). Inhibition was fully reversible and found to be identical in both F(1)F(0) membrane preparations as well as in isolated purified F(1). Interestingly, growth of E. coli was abrogated in the presence of ascaphin-8, aurein 2.2, aurein 2.3, citropin 1.1, dermaseptin, magainin II-amide, MRP, MRP-amide, melittin, or melittin-amide but was unaffected in the presence of carein 1.8, carein 1.9, maculatin 1.1, magainin II, or XT-7. Hence inhibition of F(1)-ATPase and E. coli cell growth by amphibian antimicrobial peptides suggests that their antimicrobial/anticancer properties are in part linked to their actions on ATP synthase. PMID:20100509

  9. Cryptic impacts of temperature variability on amphibian immune function.

    Science.gov (United States)

    Terrell, Kimberly A; Quintero, Richard P; Murray, Suzan; Kleopfer, John D; Murphy, James B; Evans, Matthew J; Nissen, Bradley D; Gratwicke, Brian

    2013-11-15

    Ectothermic species living in temperate regions can experience rapid and potentially stressful changes in body temperature driven by abrupt weather changes. Yet, among amphibians, the physiological impacts of short-term temperature variation are largely unknown. Using an ex situ population of Cryptobranchus alleganiensis, an aquatic North American salamander, we tested the hypothesis that naturally occurring periods of temperature variation negatively impact amphibian health, either through direct effects on immune function or by increasing physiological stress. We exposed captive salamanders to repeated cycles of temperature fluctuations recorded in the population's natal stream and evaluated behavioral and physiological responses, including plasma complement activity (i.e. bacteria killing) against Pseudomonas aeruginosa, Escherichia coli and Aeromonas hydrophila. The best-fit model (ΔAICc=0, wi=0.9992) revealed 70% greater P. aeruginosa killing after exposure to variable temperatures and no evidence of thermal acclimation. The same model predicted 50% increased E. coli killing, but had weaker support (ΔAICc=1.8, wi=0.2882). In contrast, plasma defenses were ineffective against A. hydrophila, and other health indicators (leukocyte ratios, growth rates and behavioral patterns) were maintained at baseline values. Our data suggest that amphibians can tolerate, and even benefit from, natural patterns of rapid warming/cooling. Specifically, temperature variation can elicit increased activity of the innate immune system. This immune response may be adaptive in an unpredictable environment, and is undetectable by conventional health indicators (and hence considered cryptic). Our findings highlight the need to consider naturalistic patterns of temperature variation when predicting species' susceptibility to climate change. PMID:23948472

  10. Experimental canopy removal enhances diversity of vernal pond amphibians.

    Science.gov (United States)

    Skelly, David K; Bolden, Susan R; Freidenburg, L Kealoha

    2014-03-01

    Vernal ponds are often treated as protected environments receiving special regulation and management. Within the landscapes where they are found, forest vegetation frequently dominates surrounding uplands and can grow to overtop and shade pond basins. Two bodies of research offer differing views of the role of forest canopy for vernal pond systems. Studies of landscape conversion suggest that removing forest overstory within uplands can cause local extinctions of amphibians by altering terrestrial habitat or hindering movement. Studies of canopy above pond basins imply an opposite relationship; encroachment of overstory vegetation can be associated with local extinctions potentially via changes in light, thermal, and food resource environments. Unresolved uncertainties about the role of forest canopy reveal significant gaps in our understanding of wetland species distributions and dynamics. Any misunderstanding of canopy influences is simultaneously important to managers because current practices emphasize promoting or conserving vegetation growth particularly within buffers immediately adjacent to ponds. We evaluated this apparent contradiction by conducting a landscape-scale, long-term experiment using 14 natural vernal ponds. Tree felling at six manipulated ponds was limited in spatial scope but was nevertheless effective in increasing water temperature. Compared with eight control ponds, manipulated ponds maintained more amphibian species during five years post-manipulation. There was little evidence that any species was negatively influenced, and the reproductive effort of species for which we estimated egg inputs maintained pretreatment population densities in manipulated compared with control ponds. Overall, our experiment shows that a carefully circumscribed reduction of overhead forest canopy can enhance the capacity of vernal ponds to support wildlife diversity and suggests a scale dependence of canopy influences on amphibians. These findings have

  11. Amphibians and agricultural chemicals: Review of the risks in a complex environment

    International Nuclear Information System (INIS)

    Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals. - The literature on the various mechanisms by which amphibians may be affected by agricultural chemicals is reviewed.

  12. Expansion of amphibian intronless interferons revises the paradigm for interferon evolution and functional diversity.

    Science.gov (United States)

    Sang, Yongming; Liu, Qinfang; Lee, Jinhwa; Ma, Wenjun; McVey, D Scott; Blecha, Frank

    2016-01-01

    Interferons (IFNs) are key cytokines identified in vertebrates and evolutionary dominance of intronless IFN genes in amniotes is a signature event in IFN evolution. For the first time, we show that the emergence and expansion of intronless IFN genes is evident in amphibians, shown by 24-37 intronless IFN genes in each frog species. Amphibian IFNs represent a molecular complex more complicated than those in other vertebrate species, which revises the established model of IFN evolution to facilitate re-inspection of IFN molecular and functional diversity. We identified these intronless amphibian IFNs and their intron-containing progenitors, and functionally characterized constitutive and inductive expression and antimicrobial roles in infections caused by zoonotic pathogens, such as influenza viruses and Listeria monocytogenes. Amphibians, therefore, may serve as overlooked vectors/hosts for zoonotic pathogens, and the amphibian IFN system provides a model to study IFN evolution in molecular and functional diversity in coping with dramatic environmental changes during terrestrial adaption. PMID:27356970

  13. Amphibians and agricultural chemicals: Review of the risks in a complex environment

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Reinier M., E-mail: reinier.mann@uts.edu.a [Centre for Ecotoxicology, Department of Environmental Sciences, University of Technology - Sydney, Sydney, NSW 2006 (Australia); Ecotoxicology and Environmental Contaminants Section, Department of Environment and Climate Change, New South Wales, PO Box 29, Lidcombe, NSW 1825 (Australia); Hyne, Ross V., E-mail: Ross.Hyne@environment.nsw.gov.a [Ecotoxicology and Environmental Contaminants Section, Department of Environment and Climate Change, New South Wales, PO Box 29, Lidcombe, NSW 1825 (Australia); Choung, Catherine B., E-mail: catherine.choung@environment.nsw.gov.a [Department of Biological Sciences and Physical Geography, Macquarie University, NSW 2109 (Australia); Wilson, Scott P., E-mail: s.wilson@cqu.edu.a [Centre for Environmental Management, Central Queensland University, PO Box 1319, Gladstone, QLD 4680 (Australia)

    2009-11-15

    Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals. - The literature on the various mechanisms by which amphibians may be affected by agricultural chemicals is reviewed.

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

    Science.gov (United States)

    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 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. PMID:27408554

  15. Synergistic effects of the invasive Chinese tallow (Triadica sebifera) and climate change on aquatic amphibian survival.

    Science.gov (United States)

    Saenz, Daniel; Fucik, Erin M; Kwiatkowski, Matthew A

    2013-11-01

    Changes in climate and the introduction of invasive species are two major stressors to amphibians, although little is known about the interaction between these two factors with regard to impacts on amphibians. We focused our study on an invasive tree species, the Chinese tallow (Triadica sebifera), that annually sheds its leaves and produces leaf litter that is known to negatively impact aquatic amphibian survival. The purpose of our research was to determine whether the timing of leaf fall from Chinese tallow and the timing of amphibian breeding (determined by weather) influence survival of amphibian larvae. We simulated a range of winter weather scenarios, ranging from cold to warm, by altering the relative timing of when leaf litter and amphibian larvae were introduced into aquatic mesocosms. Our results indicate that amphibian larvae survival was greatly affected by the length of time Chinese tallow leaf litter decomposes in water prior to the introduction of the larvae. Larvae in treatments simulating warm winters (early amphibian breeding) were introduced to the mesocosms early in the aquatic decomposition process of the leaf litter and had significantly lower survival compared with cold winters (late amphibian breeding), likely due to significantly lower dissolved oxygen levels. Shifts to earlier breeding phenology, linked to warming climate, have already been observed in many amphibian taxa, and with most climate models predicting a significant warming trend over the next century, the trend toward earlier breeding should continue if not increase. Our results strongly suggest that a warming climate can interact with the effects of invasive plant species, in ways we have not previously considered, to reduce the survival of an already declining group of organisms. PMID:24363907

  16. [Report on a fungus parasitizing Entamoeba histolytica].

    Science.gov (United States)

    Cao, C Q; Feng, Y S

    1989-01-01

    Infection of Entamoeba histolytica with chytridiaceous fungus Sphaerita was observed in some specimens obtained from a farmer and stained with iron-haematoxylin. The fungi were found in 78% of the cysts, mostly immature ones. Within the amoebae this parasite occurred singly, in groups, or in the form of a sporangium. It was located in the cytoplasm, the glycogen mass or the chromatoidal bars. In the same specimen, the parasitic fungus was also found in 18% of E. coli cysts; in 11% of E. nana cysts; while only one of 16 E. hartmanni cysts was parasitized. It is an interesting case of superimposed parasitism so far reported in China as well as a rare case of several species of amoebae being heavily involved with the same in the scientific literature. PMID:2548767

  17. Population genetics of the frog-killing fungus Batrachochytrium dendrobatidis

    OpenAIRE

    Morgan, Jess A T; Vance T Vredenburg; Rachowicz, Lara J.; Knapp, Roland A; Stice, Mary J.; Tunstall, Tate; Bingham, Rob E.; Parker, John M.; Longcore, Joyce E.; Moritz, Craig; Briggs, Cheryl J.; Taylor, John W.

    2007-01-01

    Global amphibian decline by chytridiomycosis is a major environmental disaster that has been attributed to either recent fungal spread or environmental change that promotes disease. Here, we present a population genetic comparison of Batrachochytrium dendrobatidis isolates from an intensively studied region of frog decline, the Sierra Nevada of California. In support of a novel pathogen, we find low diversity, no amphibian-host specificity, little correlation between fungal genotype and geogr...

  18. SYSTEMIC INFECTION AND RELATED FUNGUS: AN OVERVIEW

    OpenAIRE

    Saha Rajsekhar; Mishra Aditya Kumar

    2011-01-01

    A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds (British English: moulds), as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which are separate from plants, animals, and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. Many fungi play a crucial role in decomposition (breaking things down)...

  19. The agricultural pathology of ant fungus gardens

    OpenAIRE

    Currie, Cameron R; Mueller, Ulrich G.; Malloch, David

    1999-01-01

    Gardens of fungus-growing ants (Formicidae: Attini) traditionally have been thought to be free of microbial parasites, with the fungal mutualist maintained in nearly pure “monocultures.” We conducted extensive isolations of “alien” (nonmutualistic) fungi from ant gardens of a phylogenetically representative collection of attine ants. Contrary to the long-standing assumption that gardens are maintained free of microbial pathogens and parasites, they are in fact host to specialized parasites th...

  20. Lowland amphibians - recalculation of data on effects of diluted thyroxine

    Directory of Open Access Journals (Sweden)

    Peter Christian Endler

    2012-04-01

    Full Text Available Our previous paper described methodological problems and a generally acceptable pooling method for metamorphosis experiments and application of that method to the results of multicentre experiments performed over the course of two decades (1990 - 2010 on highland amphibians (Rana temporaria treated with a homeopathically prepared high dilution of thyroxine (“30x”. Differences between treatment groups thus calculated were in line with those obtained with other pooling methods: Thyroxine 30x does slow down metamorphosis in highland amphibians. This follow up paper provides a broader background on metamorphosis physiology and describes application of the pooling method to experiments with Rana temporaria from lowland biotopes both with a moderate dilution of thyroxine (“8x” and with 30x. Analogously prepared water was used for control (water 8x or 30x. Development was, again as above, monitored by documenting the number of animals that had entered the 4-legged stage. Experiments were carried out between 1990 and 2000 by different researchers independently and in blind. As it is well known, metamorphosis can be speeded up by thyroxine 10-8 mol/l; interestingly, thyroxine 8x may produce a reverse, i.e. inhibiting effect (p 0.05. However, an inhibiting effect on lowland larvae was found when animals were treated from the spawn stage on (p < 0.01.

  1. Linking genetic and environmental factors in amphibian disease risk.

    Science.gov (United States)

    Savage, Anna E; Becker, Carlos G; Zamudio, Kelly R

    2015-07-01

    A central question in evolutionary biology is how interactions between organisms and the environment shape genetic differentiation. The pathogen Batrachochytrium dendrobatidis (Bd) has caused variable population declines in the lowland leopard frog (Lithobates yavapaiensis); thus, disease has potentially shaped, or been shaped by, host genetic diversity. Environmental factors can also influence both amphibian immunity and Bd virulence, confounding our ability to assess the genetic effects on disease dynamics. Here, we used genetics, pathogen dynamics, and environmental data to characterize L. yavapaiensis populations, estimate migration, and determine relative contributions of genetic and environmental factors in predicting Bd dynamics. We found that the two uninfected populations belonged to a single genetic deme, whereas each infected population was genetically unique. We detected an outlier locus that deviated from neutral expectations and was significantly correlated with mortality within populations. Across populations, only environmental variables predicted infection intensity, whereas environment and genetics predicted infection prevalence, and genetic diversity alone predicted mortality. At one locality with geothermally elevated water temperatures, migration estimates revealed source-sink dynamics that have likely prevented local adaptation. We conclude that integrating genetic and environmental variation among populations provides a better understanding of Bd spatial epidemiology, generating more effective conservation management strategies for mitigating amphibian declines. PMID:26136822

  2. Evolution of erythrocyte morphology in amphibians (Amphibia: Anura

    Directory of Open Access Journals (Sweden)

    Jie Wei

    2015-10-01

    Full Text Available ABSTRACT We compared the morphology of the erythrocytes of five anurans, two toad species - Bufo gargarizans (Cantor, 1842 and Duttaphrynus melanostictus (Schneider, 1799 and three frog species - Fejervarya limnocharis (Gravenhorst, 1829, Microhyla ornata (Duméril & Bibron, 1841, and Rana zhenhaiensis (Ye, Fei & Matsui, 1995. We then reconstructed the ancestral state of erythrocyte size (ES and nuclear size (NS in amphibians based on a molecular tree. Nine morphological traits of erythrocytes were all significantly different among the five species. The results of principal component analysis showed that the first component (49.1% of variance explained had a high positive loading for erythrocyte length, nuclear length, NS and ratio of erythrocyte length/erythrocyte width; the second axis (28.5% of variance explained mainly represented erythrocyte width and ES. Phylogenetic generalized least squares analysis showed that the relationship between NS and ES was not affected by phylogenetic relationships although there was a significant linear relationship between these two variables. These results suggested that (1 the nine morphological traits of erythrocytes in the five anuran species were species-specific; (2 in amphibians, larger erythrocytes generally had larger nuclei.

  3. Anthropogenic and ecological drivers of amphibian disease (ranavirosis.

    Directory of Open Access Journals (Sweden)

    Alexandra C North

    Full Text Available Ranaviruses are causing mass amphibian die-offs in North America, Europe and Asia, and have been implicated in the decline of common frog (Rana temporaria populations in the UK. Despite this, we have very little understanding of the environmental drivers of disease occurrence and prevalence. Using a long term (1992-2000 dataset of public reports of amphibian mortalities, we assess a set of potential predictors of the occurrence and prevalence of Ranavirus-consistent common frog mortality events in Britain. We reveal the influence of biotic and abiotic drivers of this disease, with many of these abiotic characteristics being anthropogenic. Whilst controlling for the geographic distribution of mortality events, disease prevalence increases with increasing frog population density, presence of fish and wild newts, increasing pond depth and the use of garden chemicals. The presence of an alternative host reduces prevalence, potentially indicating a dilution effect. Ranavirosis occurrence is associated with the presence of toads, an urban setting and the use of fish care products, providing insight into the causes of emergence of disease. Links between occurrence, prevalence, pond characteristics and garden management practices provides useful management implications for reducing the impacts of Ranavirus in the wild.

  4. Radioautographic investigation of retinal growth in mature amphibians

    Energy Technology Data Exchange (ETDEWEB)

    Svistunov, S.A.; Mitashov, V.I.

    1986-07-01

    Growth of the retina was studied in mature intact amphibians, tritons, axolotls, ambystomas and clawed frogs, for six months using multiple injection of /sup 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.

  5. Suburbanization, estrogen contamination, and sex ratio in wild amphibian populations.

    Science.gov (United States)

    Lambert, Max R; Giller, Geoffrey S J; Barber, Larry B; Fitzgerald, Kevin C; Skelly, David K

    2015-09-22

    Research on endocrine disruption in frog populations, such as shifts in sex ratios and feminization of males, has predominantly focused on agricultural pesticides. Recent evidence suggests that suburban landscapes harbor amphibian populations exhibiting similar levels of endocrine disruption; however the endocrine disrupting chemical (EDC) sources are unknown. Here, we show that sex ratios of metamorphosing frogs become increasingly female-dominated along a suburbanization gradient. We further show that suburban ponds are frequently contaminated by the classical estrogen estrone and a variety of EDCs produced by plants (phytoestrogens), and that the diversity of organic EDCs is correlated with the extent of developed land use and cultivated lawn and gardens around a pond. Our work also raises the possibility that trace-element contamination associated with human land use around suburban ponds may be contributing to the estrogenic load within suburban freshwaters and constitutes another source of estrogenic exposure for wildlife. These data suggest novel, unexplored pathways of EDC contamination in human-altered environments. In particular, we propose that vegetation changes associated with suburban neighborhoods (e.g., from forests to lawns and ornamental plants) increase the distribution of phytoestrogens in surface waters. The result of frog sex ratios varying as a function of human land use implicates a role for environmental modulation of sexual differentiation in amphibians, which are assumed to only have genetic sex determination. Overall, we show that endocrine disruption is widespread in suburban frog populations and that the causes are likely diverse. PMID:26372955

  6. Proximity to pollution sources and risk of amphibian limb malformation.

    Science.gov (United States)

    Taylor, Brynn; Skelly, David; Demarchis, Livia K; Slade, Martin D; Galusha, Deron; Rabinowitz, Peter M

    2005-11-01

    The cause of limb deformities in wild amphibian populations remains unclear, even though the apparent increase in prevalence of this condition may have implications for human health. Few studies have simultaneously assessed the effect of multiple exposures on the risk of limb deformities. In a cross-sectional survey of 5,264 hylid and ranid metamorphs in 42 Vermont wetlands, we assessed independent risk factors for nontraumatic limb malformation. The rate of nontraumatic limb malformation varied by location from 0 to 10.2%. Analysis of a subsample did not demonstrate any evidence of infection with the parasite Ribeiroia. We used geographic information system (GIS) land-use/land-cover data to validate field observations of land use in the proximity of study wetlands. In a multiple logistic regression model that included land use as well as developmental stage, genus, and water-quality measures, proximity to agricultural land use was associated with an increased risk of limb malformation (odds ratio = 2.26; 95% confidence interval, 1.42-3.58; p < 0.001). The overall discriminant power of the statistical model was high (C = 0.79). These findings from one of the largest systematic surveys to date provide support for the role of chemical toxicants in the development of amphibian limb malformation and demonstrate the value of an epidemiologic approach to this problem. PMID:16263502

  7. 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.

  8. Filling a gap in the distribution of Batrachochytrium dendrobatidis: evidence in amphibians from northern China.

    Science.gov (United States)

    Zhu, Wei; Fan, Liqing; Soto-Azat, Claudio; Yan, Shaofei; Gao, Xu; Liu, Xuan; Wang, Supen; Liu, Conghui; Yang, Xuejiao; Li, Yiming

    2016-03-30

    Chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) has been recognized as a major driver of amphibian declines worldwide. Central and northern Asia remain as the greatest gap in the knowledge of the global distribution of Bd. In China, Bd has recently been recorded from south and central regions, but areas in the north remain poorly surveyed. In addition, a recent increase in amphibian farming and trade has put this region at high risk for Bd introduction. To investigate this, we collected a total of 1284 non-invasive skin swabs from wild and captive anurans and caudates, including free-ranging, farmed, ornamental, and museum-preserved amphibians. Bd was detected at low prevalence (1.1%, 12 of 1073) in live wild amphibians, representing the first report of Bd infecting anurans from remote areas of northwestern China. We were unable to obtain evidence of the historical presence of Bd from museum amphibians (n = 72). Alarmingly, Bd was not detected in wild amphibians from the provinces of northeastern China (>700 individuals tested), but was widely present (15.1%, 21 of 139) in amphibians traded in this region. We suggest that urgent implementation of measures is required to reduce the possibility of further spread or inadvertent introduction of Bd to China. It is unknown whether Bd in northern China belongs to endemic and/or exotic genotypes, and this should be the focus of future research. PMID:27025313

  9. The amphibian skin-associated microbiome across species, space and life history stages.

    Science.gov (United States)

    Kueneman, Jordan G; Parfrey, Laura Wegener; Woodhams, Douglas C; Archer, Holly M; Knight, Rob; McKenzie, Valerie J

    2014-03-01

    Skin-associated bacteria of amphibians are increasingly recognized for their role in defence against pathogens, yet we have little understanding of their basic ecology. Here, we use high-throughput 16S rRNA gene sequencing to examine the host and environmental influences on the skin microbiota of the cohabiting amphibian species Anaxyrus boreas, Pseudacris regilla, Taricha torosa and Lithobates catesbeianus from the Central Valley in California. We also studied populations of Rana cascadae over a large geographic range in the Klamath Mountain range of Northern California, and across developmental stages within a single site. Dominant bacterial phylotypes on amphibian skin included taxa from Bacteroidetes, Gammaproteobacteria, Alphaproteobacteria, Firmicutes, Sphingobacteria and Actinobacteria. Amphibian species identity was the strongest predictor of microbial community composition. Secondarily, within a given amphibian species, wetland site explained significant variation. Amphibian-associated microbiota differed systematically from microbial assemblages in their environments. Rana cascadae tadpoles have skin bacterial communities distinct from postmetamorphic conspecifics, indicating a strong developmental shift in the skin microbes following metamorphosis. Establishing patterns observed in the skin microbiota of wild amphibians and environmental factors that underlie them is necessary to understand skin symbiont community assembly, and ultimately, the role skin microbiota play in the extended host phenotype including disease resistance. PMID:24171949

  10. Assessing effects of pesticides on amphibians and reptiles: status and needs

    Science.gov (United States)

    Hall, R.J.; Henry, P.F.P.

    1992-01-01

    Growing concern about the decline of certain amphibian populations and for conservation of amphibians and reptiles has led to renewed awareness of problems from pesticides. Testing amphibians and reptiles as a requirement for chemical registration has been proposed but is difficult because of the phylogenetic diversity of these groups. Information from the literature and research may determine whether amphibians and reptiles are adequately protected by current tests for mammals, birds, and fish. Existing information indicates that amphibians are unpredictably more resistant to certain cholinesterase inhibitors, and more sensitive to two chemicals used in fishery applications than could have been predicted. A single study on one species of lizard suggests that reptiles may be close in sensitivity to mammals and birds. Research on effects of pesticides on amphibians and reptiles should compare responses to currently tested groups and should seek to delineate those taxa and chemicals for which cross-group prediction is not possible. New tests for amphibians and reptiles should rely to the greatest extent possible on existing data bases, and should be designed for maximum economy and minimum harm to test animals. A strategy for developing the needed information is proposed. Good field testing and surveillance of chemicals in use may compensate for failures of predictive evaluations and may ultimately lead to improved tests.

  11. Atrazine Contamination in Water and the Impact on Amphibian Populations: A Bioassay That Measures Water Quality

    Science.gov (United States)

    Hayes, T. B.

    2001-12-01

    In recent laboratory studies, we showed that atrazine, a common herbicide, can inhibit metamorphosis, produce hermaphrodites, and inhibit male development in amphibians. In part, these effects are due to a decrease in androgen levels. These effects occur at ecologically relevant low doses (0.1 ppb), and the effective levels are below the current drinking level standard and below contaminant levels found even in rainfall in some areas. Thus, the impact of this widespread compound on free-ranging amphibians is a concern. We undertook a large-scale study to examine atrazine levels in a variety of habitats (temporary pools, rivers, lakes and ponds, and field runoff) across the US where atrazine is used and areas that report no atrazine use. Also, we collected amphibians at each site to examine them for developmental abnormalities. These ongoing studies will help determine the extent of atrazine contamination and its potential impact on amphibian populations. The concern for atrazine's impact is increased, because the mechanism through which the compound produces this effect (inhibition of androgen production) is commonly observed in fish, reptiles and mammals in addition to amphibians, although amphibians appear to sensitive at much lower doses. Thus, effects on amphibians may indicate a much broader impact.

  12. Fungus-Growing Termites Originated in African Rain Forest

    DEFF Research Database (Denmark)

    Aanen, Duur Kornelis; Eggleton, Paul

    2005-01-01

    consumed (cf. [ [1] and [2] ]). Fungus-growing termites are found throughout the Old World tropics, in rain forests and savannas, but are ecologically dominant in savannas [ 3 ]. Here, we reconstruct the ancestral habitat and geographical origin of fungus-growing termites. We used a statistical model of...... fungus growing by termites is ecologically most successful under the variable, unfavorable conditions of the savanna, it seems to have evolved under the more constant and favorable conditions of the rain forest....

  13. Stable Isotopes Reveal Trophic Partitioning and Trophic Plasticity of a Larval Amphibian Guild.

    Directory of Open Access Journals (Sweden)

    Rosa Arribas

    Full Text Available Temporary ponds are highly variable systems where resource availability and community structure change extensively over time, and consequently the food web is highly dynamic. Amphibians play a critical role both as consumers and prey in aquatic communities and yet there is still little information on the trophic status of most amphibians. More importantly, little is known about the extent to which they can alter their trophic ecology in response to changing conditions. We experimentally investigated the effects of increased amphibian density, presence of intraguild competitors, and presence of native and invasive predators (either free or caged on the trophic status of a Mediterranean amphibian guild, using stable isotopes. We observed variations in δ13C and δ15N isotopic values among amphibian species and treatments and differences in their food sources. Macrophytes were the most important food resource for spadefoot toad tadpoles (Pelobates cultripes and relatively important for all anurans within the guild. High density and presence of P. cultripes tadpoles markedly reduced macrophyte biomass, forcing tadpoles to increase their feeding on detritus, algae and zooplankton, resulting in lower δ13C values. Native dytiscid predators only changed the isotopic signature of newts whereas invasive red swamp crayfish had an enormous impact on environmental conditions and greatly affected the isotopic values of amphibians. Crayfish forced tadpoles to increase detritus ingestion or other resources depleted in δ13C. We found that the opportunistic amphibian feeding was greatly conditioned by intra- and interspecific competition whereas non-consumptive predator effects were negligible. Determining the trophic plasticity of amphibians can help us understand natural and anthropogenic changes in aquatic ecosystems and assess amphibians' ability to adjust to different environmental conditions.

  14. Stable Isotopes Reveal Trophic Partitioning and Trophic Plasticity of a Larval Amphibian Guild.

    Science.gov (United States)

    Arribas, Rosa; Díaz-Paniagua, Carmen; Caut, Stephane; Gomez-Mestre, Ivan

    2015-01-01

    Temporary ponds are highly variable systems where resource availability and community structure change extensively over time, and consequently the food web is highly dynamic. Amphibians play a critical role both as consumers and prey in aquatic communities and yet there is still little information on the trophic status of most amphibians. More importantly, little is known about the extent to which they can alter their trophic ecology in response to changing conditions. We experimentally investigated the effects of increased amphibian density, presence of intraguild competitors, and presence of native and invasive predators (either free or caged) on the trophic status of a Mediterranean amphibian guild, using stable isotopes. We observed variations in δ13C and δ15N isotopic values among amphibian species and treatments and differences in their food sources. Macrophytes were the most important food resource for spadefoot toad tadpoles (Pelobates cultripes) and relatively important for all anurans within the guild. High density and presence of P. cultripes tadpoles markedly reduced macrophyte biomass, forcing tadpoles to increase their feeding on detritus, algae and zooplankton, resulting in lower δ13C values. Native dytiscid predators only changed the isotopic signature of newts whereas invasive red swamp crayfish had an enormous impact on environmental conditions and greatly affected the isotopic values of amphibians. Crayfish forced tadpoles to increase detritus ingestion or other resources depleted in δ13C. We found that the opportunistic amphibian feeding was greatly conditioned by intra- and interspecific competition whereas non-consumptive predator effects were negligible. Determining the trophic plasticity of amphibians can help us understand natural and anthropogenic changes in aquatic ecosystems and assess amphibians' ability to adjust to different environmental conditions. PMID:26091281

  15. 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 < 1% of model runs and for only 2 of the 4 species, because landscape-scale populations were able to persist via dispersal even despite frequent local extinctions. Yet for all species, population sizes were reduced to -50% in all clear-cut scenarios, regardless of the size of harvested patches. These findings suggest that debate over timber harvesting on pool-breeding 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

  16. Amphibians and Reptiles of the state of Nuevo León, Mexico

    OpenAIRE

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

  17. Dynamics of radionuclide accumulation at amphibians and reptiles in the Poles'e state radioecological reserve

    International Nuclear Information System (INIS)

    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/km2. 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

  18. 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.

  19. 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......It is widely believed that contemporary climate determines large-scale patterns of species richness. An alternative view proposes that species richness reflects biotic responses to historic climate changes. These competing "contemporary climate" vs "historic climate" hypotheses have been vigorously...... than contemporary climate; and that the 0°C isotherm of the LGM delimits the distributions of narrow-ranging species, whereas the current 0°C isotherm limits the distributions of wide-ranging species. Our analyses contradict previous studies of large-scale species richness patterns and support the view...

  20. 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

    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 in the realised climatic niches is explained on higher taxonomic levels, and whether the climatic niches of species within a given taxonomic group are more similar than between taxonomic groups. We found evidence for phylogenetic signals in realised climatic niches although the strength of the...

  1. AMPHIBIAN COMMUNITIES IN BIOGEOCOENOSIS WITH DIFFERENT STAGES OF ANTHROPOGENIC CLYMAX

    Directory of Open Access Journals (Sweden)

    Marchenkovskaya А. А.

    2013-04-01

    Full Text Available We examined the abundance of juvenile (fingerlings and yearlings and sexually mature (3-6 years of various anurans at various biotopes with different degrees of anthropogenic influence. Population analysis has revealed that the number of juveniles in all the habitats are depended on type and level of anthropogenic influence. In all the habitats the most numerous species was synanthropic bufo viridis. In biotopes with high contamination of pollutants, only one species of amphibians - the marsh frog has populations with juveniles migrating here in the early fall. The highest number of mature individuals registered for the population of Bombina bombina, pelobates fuscus and in one biotope for hyla arborea. The populations of pelophylax ridibundus could be considered as the most balanced by number of juvenile and mature individuals.

  2. Correlates of species richness in the largest Neotropical amphibian radiation.

    Science.gov (United States)

    Gonzalez-Voyer, A; Padial, J M; Castroviejo-Fisher, S; de la Riva, I; Vilà, C

    2011-05-01

    Although tropical environments are often considered biodiversity hotspots, it is precisely in such environments where least is known about the factors that drive species richness. Here, we use phylogenetic comparative analyses to study correlates of species richness for the largest Neotropical amphibian radiation: New World direct-developing frogs. Clade-age and species richness were nonsignificantly, negatively correlated, suggesting that clade age alone does not explain among-clade variation in species richness. A combination of ecological and morphological traits explained 65% of the variance in species richness. A more vascularized ventral skin, the ability to colonize high-altitude ranges, encompassing a large variety of vegetation types, correlated significantly with species richness, whereas larger body size was marginally correlated with species richness. Hence, whereas high-altitude ranges play a role in shaping clade diversity in the Neotropics, intrinsic factors, such as skin structures and possibly body size, might ultimately determine which clades are more speciose than others. PMID:21401771

  3. Visual implant elastomer mark retention through metamorphosis in amphibian larvae

    Science.gov (United States)

    Grant, E.H.C.

    2008-01-01

    Questions in population ecology require the study of marked animals, and marks are assumed to be permanent and not overlooked by observers. I evaluated retention through metamorphosis of visual implant elastomer marks in larval salamanders and frogs and assessed error in observer identification of these marks. I found 1) individual marks were not retained in larval wood frogs (Rana sylvatica), whereas only small marks were likely to be retained in larval salamanders (Eurycea bislineata), and 2) observers did not always correctly identify marked animals. Evaluating the assumptions of marking protocols is important in the design phase of a study so that correct inference can be made about the population processes of interest. This guidance should be generally useful to the design of mark?recapture studies, with particular application to studies of larval amphibians.

  4. Metabolites from mangrove endophytic fungus Dothiorella sp.

    Institute of Scientific and Technical Information of China (English)

    XUQingyan; WANGJianfeng; HUANGYaojian; ZHENGZhonghui; SONGSiyang; ZHANGYongmin; SUWenjin

    2004-01-01

    Mangroves are special woody plant communities in the intertidal zone of tropical and subtropical coasts. They prove to be a natural microorganisms and new metabolites storage. In the study of mangrove endophytic fungi metabolites, four new compounds, Compounds 1, 2, 3 and 4, as well as a known octaketide, cytosporone B (5), are isolated from an endophytic fungus, Dothiorella sp., HTF3. They all show cytotoxic activities. The elucidation of these structures is mainly based on 1D/2D NMR and ESI-MS spectral analyses.

  5. Thyroid Histopathology Assessments for the Amphibian Metamorphosis Assay to Detect Thyroid-active Substances

    Science.gov (United States)

    In support of an Organization for Economic Cooperation and Development (OECD) Amphibian Metamorphosis Assay (AMA) Test Guideline for the detection of substances that interact with the hypothalamic-pituitary-thyroid axis, a document was developed that provides a standardized appro...

  6. Sensitivity of Coastal Environments and Wildlife to Spilled Oil: Central California: REPTILEL (Reptile and Amphibian Lines)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for amphibians and reptiles in Central California. Vector lines in this data set represent general stream...

  7. Preliminary Assessment for Abnormal Amphibians on National Wildlife Refuges in the Southeast Region FY 2008

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Preliminary screening assessments for abnormal amphibians were initiated on national wildlife refuges (NWRs) in the southeast region in 2000, with additional...

  8. Study on abnormal amphibians on National Wildlife Refuges: Questions and answers

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document answers questions related to a 10year abnormal amphibian study conducted on U.S. National Wildlife Refuges. Topics include: why the study was...

  9. Survey of reptiles and amphibians of North Platte National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This proposal is for surveying reptiles and amphibians of North Platte National Wildlife Refuge for the specific goals of generating a species list, species...

  10. Summary of amphibian and reptile surveys 2001 - North Mississippi Refuges Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report details surveys for amphibians and reptiles on Dahomey, Coldwater River, and Dahomey NWRs in 2001. Sampling methods and protocols are also included.

  11. Rhode Island, Connecticut, New York, and New Jersey 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 threatened/endangered sea turtles, diamondback terrapins, and rare reptiles/amphibians in coastal...

  12. Species List of Alaskan Birds, Mammals, Fish, Amphibians, Reptiles, and Invertebrates. Alaska Region Report Number 82.

    Science.gov (United States)

    Taylor, Tamra Faris

    This publication contains a detailed list of the birds, mammals, fish, amphibians, reptiles, and invertebrates found in Alaska. Part I lists the species by geographical regions. Part II lists the species by the ecological regions of the state. (CO)

  13. Quantifying Amphibian Pesticide Body Burdens for Active Ingredients Versus Formulations Through Dermal Exposure

    Science.gov (United States)

    Widespread pesticide applications throughout agricultural landscapes pose a risk to post-metamorphic amphibians leaving or moving between breeding ponds in terrestrial habitats. Recent studies indicate that the inactive ingredients in pesticide formulations may be equally or more...

  14. Innate immune system targets asthma-linked fungus for destruction

    OpenAIRE

    Whyte, Barry James

    2008-01-01

    A new study shows that the innate immune system of humans is capable of killing a fungus linked to airway inflammation, chronic rhinosinusitis, and bronchial asthma. Researchers at Mayo Clinic and the Virginia Bioinformatics Institute at Virginia Tech have revealed that eosinophils, a particular type of white blood cell, exert a strong immune response against the environmental fungus Alternaria alternata.

  15. Phomalactone from a phytopathogenic fungus infecting Zinnia elegans (Asteraceae) leaves

    Science.gov (United States)

    Zinnia elegans plants are infected by a fungus that causes necrosis with dark red spots particularly in late spring to the middle of summer in the Mid-South part of the United States. This fungal disease when untreated causes the leaves to wilt and eventually kills the plant. The fungus was isolated...

  16. CHARACTERIZATION OF AN ANAEROBIC FUNGUS FROM LLAMA FECES

    NARCIS (Netherlands)

    MARVINSIKKEMA, FD; LAHPOR, GA; KRAAK, MN; GOTTSCHAL, JC; PRINS, RA

    1992-01-01

    An anaerobic fungus was isolated from Hama faeces. Based on its morphological characteristics, polyflagellated zoospores, extensive rhizoid system and the formation of monocentric colonies, the fungus is assigned to the genus Neocallimastix. Neocallimastix sp. L2 is able to grow on several poly-, ol

  17. Forests as promoters of terrestrial life-history strategies in East African amphibians

    OpenAIRE

    Müller, Hendrik; Liedtke, Hans Christoph; Menegon, Michele; Beck, Jan; Ballesteros-Mejia, Liliana; Nagel, Peter; Loader, Simon Paul

    2013-01-01

    Many amphibian lineages show terrestrialization of their reproductive strategy and breeding is partially or completely independent of water. A number of causal factors have been proposed for the evolution of terrestrialized breeding. While predation has received repeated attention as a potential factor, the influence of other factors such as habitat has never been tested using appropriate data or methods. Using a dataset that comprises 180 amphibian species from various East African habitats,...

  18. Amphibian conservation in human shaped environments: landscape dynamics, habitat modeling and metapopulation analyses

    OpenAIRE

    Zanini, Flavio; Schlaepfer, Rodolphe; Golay, François

    2007-01-01

    Global biodiversity is experiencing a worrying decline. Habitats destruction, associated to their degradation and fragmentation are among the greatest causes. Amphibians are particularly interesting because they are more threatened and decline more rapidly than either birds or mammals. In this context, the objective of our research is to improve some methodological approaches and offer practical scientific bases for decision making in landscape management and amphibian conservation. Our study...

  19. Amphibian conservation in human shaped environments: landscape dynamics, habitat modeling and metapopulation analyses

    OpenAIRE

    Zanini, Flavio

    2006-01-01

    Global biodiversity is experiencing a worrying decline. Habitats destruction, associated to their degradation and fragmentation are among the greatest causes. Amphibians are particularly interesting because they are more threatened and decline more rapidly than either birds or mammals. In this context, the objective of our research is to improve some methodological approaches and offer practical scientific bases for decision making in landscape management and amphibian conservation. Our study...

  20. Climatic change and wetland desiccation cause amphibian decline in Yellowstone National Park

    OpenAIRE

    McMenamin, Sarah K.; Hadly, Elizabeth A.; Wright, Christopher K.

    2008-01-01

    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 decreasin...

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

    OpenAIRE

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

    2011-01-01

    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 t...

  2. Expression Profiling the Temperature-Dependent Amphibian Response to Infection by Batrachochytrium dendrobatidis

    OpenAIRE

    Ribas, Laia; Li, Ming-Shi; Doddington, Benjamin J.; Robert, Jacques; Seidel, Judith A.; Kroll, J. Simon; Zimmerman, Lyle B.; Grassly, Nicholas C.; Trenton W J Garner; Fisher, Matthew C

    2009-01-01

    Amphibians are experiencing a panzootic of unprecedented proportions caused by the emergence of Batrachochytrium dendrobatidis (Bd). However, all species are not equally at risk of infection, and risk is further modified by environmental variables, specifically temperature. In order to understand how, and when, hosts mount a response to Bd we analysed infection dynamics and patterns of gene expression in the model amphibian species Silurana (Xenopus) tropicalis. Mathematical modelling of infe...

  3. Reduced Itraconazole Concentration and Durations Are Successful in Treating Batrachochytrium dendrobatidis Infection in Amphibians

    OpenAIRE

    Laura A Brannelly

    2014-01-01

    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 acro...

  4. Non-native fish in mountain lakes: effects on a declining amphibian and ecosystem subsidy

    OpenAIRE

    Lawler, Sharon P; Pope, Karen L

    2006-01-01

    Wilderness water resources often provide wildlife habitat and associated recreational opportunities, such as angling or birdwatching. Introduced trout in mountain lakes could affect terrestrial wildlife by changing ecosystem subsidy, which is the flow of nutrients and organisms from aquatic to terrestrial habitats. Trout prey upon larval amphibians and aquatic insects, and the adult stages of aquatic insects and amphibians are prey for bats, birds, snakes, and other terrestrial insectivores. ...

  5. Amphibians biochemical indices from reservoirs of different levels of waste discharge

    Directory of Open Access Journals (Sweden)

    I. N. Zalipuha

    2009-04-01

    Full Text Available Influence of uranium mining and processing wastes on the metabolism of common amphibian species of the Dnieper region – the marsh frog (Pelophylax ridibundus – from differently contaminated reservoirs. The change of protein, lipids and carbohydrates in organs and tissues of frogs with ageing and under influence of the pollution. Considerable increase of energy consumption at the expense of lipids and carbohydrates is one of biochemical adaptations. It promotes partial resistance of amphibians to the influence of uranium mining wastes.

  6. TEMPERATURE AND PRECIPITATION AS PREDICTORS OF SPECIES RICHNESS IN NORTHERN ANDEAN AMPHIBIANS FROM COLOMBIA

    OpenAIRE

    Ortiz-Yusty Carlos Eduardo; Páez Vivian; Zapata Fernando

    2013-01-01

    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 ...

  7. Relationships between trout stocking and amphibians in British Columbia's Southern Interior lakes

    OpenAIRE

    Hirner, Joanna Lynne McGarvie

    2006-01-01

    Stocking lakes with non-native trout to encourage recreational fishing causes changes in lake ecosystems that can negatively affect biodiversity. I examined associations between rainbow trout (Oncorhynchus mykiss) and amphibians in small lakes of British Columbia’s Southern Interior by comparing abundance, growth, and probability of presence of aquatic breeding amphibians between lakes with and without trout. My evidence suggests that abundance of long-toed salamander (Ambystoma macrodactylum...

  8. Evaluation of seven aquatic sampling methods for amphibians and other aquatic fauna

    Science.gov (United States)

    Gunzburger, M.S.

    2007-01-01

    To design effective and efficient research and monitoring programs researchers must have a thorough understanding of the capabilities and limitations of their sampling methods. Few direct comparative studies exist for aquatic sampling methods for amphibians. The objective of this study was to simultaneously employ seven aquatic sampling methods in 10 wetlands to compare amphibian species richness and number of individuals detected with each method. Four sampling methods allowed counts of individuals (metal dipnet, D-frame dipnet, box trap, crayfish trap), whereas the other three methods allowed detection of species (visual encounter, aural, and froglogger). Amphibian species richness was greatest with froglogger, box trap, and aural samples. For anuran species, the sampling methods by which each life stage was detected was related to relative length of larval and breeding periods and tadpole size. Detection probability of amphibians varied across sampling methods. Box trap sampling resulted in the most precise amphibian count, but the precision of all four count-based methods was low (coefficient of variation > 145 for all methods). The efficacy of the four count sampling methods at sampling fish and aquatic invertebrates was also analyzed because these predatory taxa are known to be important predictors of amphibian habitat distribution. Species richness and counts were similar for fish with the four methods, whereas invertebrate species richness and counts were greatest in box traps. An effective wetland amphibian monitoring program in the southeastern United States should include multiple sampling methods to obtain the most accurate assessment of species community composition at each site. The combined use of frogloggers, crayfish traps, and dipnets may be the most efficient and effective amphibian monitoring protocol. ?? 2007 Brill Academic Publishers.

  9. Waterbody availability and use by amphibian communities in a rural landscape

    OpenAIRE

    Plăiaşu, Rodica; Băncilă, Raluca; Samoilă, Ciprian; Hartel, Tibor; Cogălniceanu, Dan

    2012-01-01

    Rural landscapes in central and eastern Europe provide valuable ecosystem services and support high levels of biodiversity. These landscapes face an increasing pressure from human development and changes in agricultural practices. Pond-breeding amphibians and their breeding habitats are especially vulnerable to land-use changes. We studied waterbody use by amphibians in a rural landscape from Haţeg Geopark, Central Romania, a region where large areas are still under traditional land use. We s...

  10. Effects of timber harvesting on terrestrial survival of pond-breeding amphibians

    OpenAIRE

    Todd, BD; Blomquist, SM; Harper, EB; Osbourn, MS

    2014-01-01

    Successful forest management for multiple uses requires balancing extractive practices with maintaining biodiversity, among other important goals. Amphibians comprise an important and abundant part of the biodiversity of many forests. Previous studies have documented declines in the abundance and diversity of amphibians in harvested forests. However, only recently have studies begun to elucidate the mechanisms that underlie such declines. Here, we studied the effects of timber harvesting on s...

  11. Amphibians of Serra Bonita, southern Bahia: a new hotpoint within Brazil’s Atlantic Forest hotspot

    OpenAIRE

    Iuri Dias; Tadeu Medeiros; Marcos Vila Nova; Mirco Solé

    2014-01-01

    Abstract We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km2 with steep altitudinal gradients (200–950 m a.s.l.) located in the municipalities of Camacan and Pau-Brasil, southern Bahia State, Brazil. Data were obtained at 38 sampling sites (including ponds and transects within the forest and in streams), through active and visual and acoustic searches, pitfall traps, and opportunistic encounters. We recorded 80 amphibian species...

  12. Effects of Changing Density and Food Level on Metamorphosis of a Desert Amphibian, Scaphiopus Couchii

    OpenAIRE

    Newman, R.A.

    1994-01-01

    Amphibians that breed in temporary ponds provide a good opportunity to study the ecological and evolutionary consequences of environmental variability. Ephemeral aquatic habitats provide larval amphibians a transient and highly variable opportunity for growth. In the desert ponds used by Couch's spadefoot toad (Scaphiopus couchii), tadpole density varies considerably among ponds and often increases within a pond as it dries. Models of optimal size and timing of metamorphosis predict that, rel...

  13. Man-made Mediterranean temporary ponds as a tool for amphibian conservation

    OpenAIRE

    Ruhí i Vidal, Albert; San Sebastian, Olatz; Feo, Carles; Franch, Marc; Gascón Garcia, Stéphanie; Richter Boix, Alex; Boix Masafret, Dani; Gustavo A. Llorente

    2012-01-01

    Mediterranean temporary ponds (MTPs) are crucial breeding sites for local amphibians, a faunal group in decline in the Mediterranean mainly due to wetland destruction. Although the disappearance of lentic habitats in other regions of the world has been ameliorated by the creation and restoration of wetlands, these tactics remain untested in Mediterranean wetlands. To evaluate the amphibian colonization dynamics of artificial MTPs in the north-eastern Iberian Peninsula, we monitored two artifi...

  14. Stable Isotopes Reveal Trophic Partitioning and Trophic Plasticity of a Larval Amphibian Guild

    OpenAIRE

    Arribas, Rosa; Díaz-Paniagua, Carmen; Caut, Stephane; Gomez-Mestre, Ivan

    2015-01-01

    Temporary ponds are highly variable systems where resource availability and community structure change extensively over time, and consequently the food web is highly dynamic. Amphibians play a critical role both as consumers and prey in aquatic communities and yet there is still little information on the trophic status of most amphibians. More importantly, little is known about the extent to which they can alter their trophic ecology in response to changing conditions. We experimentally inves...

  15. Amphibians of Serra Bonita, southern Bahia: a new hotpoint within Brazil’s Atlantic Forest hotspot

    OpenAIRE

    Dias,Iuri; Medeiros,Tadeu; Vila Nova,Marcos; Solé, Mirco

    2014-01-01

    We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km2 with steep altitudinal gradients (200–950 m a.s.l.) located in the municipalities of Camacan and Pau-Brasil, southern Bahia State, Brazil. Data were obtained at 38 sampling sites (including ponds and transects within the forest and in streams), through active and visual and acoustic searches, pitfall traps, and opportunistic encounters. We recorded 80 amphibian species distribu...

  16. Amphibian mortality events and ranavirus outbreaks in the Greater Yellowstone Ecosystem

    Science.gov (United States)

    Patla, Debra A.; St-Hilaire, Sophia; Rayburn, Andrew P.; Hossack, Blake R.; Peterson, Charles R.

    2016-01-01

    Mortality events in wild amphibians go largely undocumented, and where events are detected, the numbers of dead amphibians observed are probably a small fraction of actual mortality (Green and Sherman 2001; Skerratt et al. 2007). Incidental observations from field surveys can, despite limitations, provide valuable information on the presence, host species, and spatial distribution of diseases. Here we summarize amphibian mortality events and diagnoses recorded from 2000 to 2014 in three management areas: Yellowstone National Park; Grand Teton National Park (including John D. Rockefeller, Jr. Memorial Parkway); and the National Elk Refuge, which together span a large portion of protected areas within the Greater Yellowstone Ecosystem (GYE; Noss et al. 2002). Our combined amphibian monitoring projects (e.g., Gould et al. 2012) surveyed an average of 240 wetlands per year over the 15 years. Field crews recorded amphibian mortalities during visual encounter and dip-netting surveys and collected moribund and dead specimens for diagnostic examinations. Amphibian and fish research projects during these years contributed additional mortality observations, specimens, and diagnoses.

  17. New Development Trend of Edible Fungus Industry in China

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    We elaborate support system of edible fungus industry from outlook on ecological economic development, legislation and standardization of variety approval, multiple-function innovation platform of industrial development research, and perfect talent cultivation and education system. Besides, we analyze the development trend of edible fungus industry from competitive advantages, position and role in national food security, industrial development trend driven by internal demand, diversified industrial development model, division of labor within the industry, and expansion of industrial chain. Then, from the point of zoning and planning of edible fungus industry, we put forward suggestions that it should start from modern industrial system and take the industrial cluster development and optimization as guidance. In addition, we present technical innovation direction of industrial development. It is proposed to strengthen propaganda, build industrial cultural atmosphere, and expand social cognition degree of edible fungus industry to promote its redevelopment. Finally, it is expected to promote international influence of edible fungus industry through experts appealing for policy support.

  18. Antimicrobial chemical constituents from endophytic fungus Phomasp.

    Institute of Scientific and Technical Information of China (English)

    Hidayat Hussain; Siegfried Draeger; Barbara Schulz; Karsten Krohn; Ines Kock; Ahmed Al-Harrasi; Ahmed Al-Rawahi; Ghulam Abbas; Ivan R Green; Afzal Shah; Amin Badshah; Muhammad Saleem

    2014-01-01

    Objective:To evaluate the antimicrobial potential of different extracts of the endophytic fungus Phomasp. and the tentative identification of their active constituents.Methods:The extract and compounds were screened for antimicrobial activity using theAgarWellDiffusionMethod. Four compounds were purified using column chromatography and their structures were assigned using1H and13CNMR spectra,DEPT,2DCOSY,HMQC andHMBC experiments.Results:The ethyl acetate fraction ofPhomasp. showed good antifungal, antibacterial, and algicidal properties.One new dihydrofuran derivative, named phomafuranol(1), together with three known compounds, phomalacton(2),(3R)-5-hydroxymellein(3) and emodin(4) were isolated from the ethyl acetate fraction ofPhomasp.Preliminary studies indicated that phomalacton(2) displayed strong antibacterial, good antifungal and antialgal activities.Similarly(3R)-5-hydroxymellein (3) and emodin(4) showed good antifungal, antibacterial and algicidal properties.Conclusions:Antimicrobial activities of the ethyl acetate fraction of the endophytic fungusPhomasp. and isolated compounds clearly demonstrate thatPhomasp. and its active compounds represent a great potential for the food, cosmetic and pharmaceutical industries.

  19. Herpetofaunal assemblage with special emphasis on community structure and spatiality in amphibians of Cauvery delta region, Tamil Nadu

    Directory of Open Access Journals (Sweden)

    Anukul Nath

    2012-12-01

    Full Text Available We studied the amphibian community structure, spatial overlap and herpetofaunal assemblage at Mannampandal, Tamil Nadu during October, 2010 to January, 2011. The survey methods involved careful visual estimation of amphibians in all the possible microhabitats present in the study area. Five different microhabitat categories were selected, viz., leaf litters, temporary water pools, tree holes, shrubs & grasses (ground vegetation, pathways, open floor & outer edges of buildings. We identified 26 species of reptiles and 14 species of amphibians. There was a significant difference found among the amphibian species occupying in different microhabitats. Species diversity was calculated, Shanon-Wiener H'= 1.55. The high niche overlap was found between Duttaphrynus scaber and Uperodon systoma followed by Fejervarya sp. and Sphaerotheca breviceps. The present study on amphibian community is just a representation to show the microhabitat occupancy and adjustment by the amphibians in human settlements and competition among them as, spatial resource partitioning.

  20. Diversity and abundance of amphibian species in the Guguftu highland and Chefa wetland, Amhara Regional State, Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Abeje Kassie Teme; Mengistu Wale Mollaleign; Asersie MekonnenAregie

    2016-01-01

    Objective: To describe the population status, abundance and diversity of amphibians found in Guguftu highland and Chefa wetland. Methods: The present study dealed with amphibian diversity at Guguftu highland and Chefa wetland during the period of August 2015 to September 2015. Transect line and visual encounter survey methods were used in careful visual estimation and amphibians were recorded in all possible habitats of the study area. Results: The total of 251 individuals of amphibians within 12 species grouped into 5 families were recorded in the Guguftu highland and Chefa wetland. Chefa wetland had the highest species abundance as well as richness with a total of 231 individuals falling in 11 species. Conclusions: This study reveals that the Chefa wetland is rich in amphibian diversity and supports many more species. Further studies are needed on molecular basis, population structure, habitat use by amphibians for better understanding and also imposing several conservation strategies in Chefa wetland.

  1. Diversity and abundance of amphibian species in the Guguftu highland and Chefa wetland, Amhara Regional State, Ethiopia

    Directory of Open Access Journals (Sweden)

    Abeje Kassie Teme

    2016-06-01

    Full Text Available Objective: To describe the population status, abundance and diversity of amphibians found in Guguftu highland and Chefa wetland. Methods: The present study dealed with amphibian diversity at Guguftu highland and Chefa wetland during the period of August 2015 to September 2015. Transect line and visual encounter survey methods were used in careful visual estimation and amphibians were recorded in all possible habitats of the study area. Results: The total of 251 individuals of amphibians within 12 species grouped into 5 families were recorded in the Guguftu highland and Chefa wetland. Chefa wetland had the highest species abundance as well as richness with a total of 231 individuals falling in 11 species. Conclusions: This study reveals that the Chefa wetland is rich in amphibian diversity and supports many more species. Further studies are needed on molecular basis, population structure, habitat use by amphibians for better understanding and also imposing several conservation strategies in Chefa wetland.

  2. Screening chemicals for thyroid-disrupting activity: A critical comparison of mammalian and amphibian models.

    Science.gov (United States)

    Pickford, Daniel B

    2010-11-01

    In order to minimize risks to human and environmental health, chemical safety assessment programs are being reinforced with toxicity tests more specifically designed for detecting endocrine disrupters. This includes the necessity to detect thyroid-disrupting chemicals, which may operate through a variety of modes of action, and have potential to impair neurological development in humans, with resulting deficits of individual and social potential. Mindful of these concerns, the consensus favors in vivo models for both hazard characterization (testing) and hazard identification (screening) steps, in order to minimize false negatives. Owing to its obligate dependence on thyroid hormones, it has been proposed that amphibian metamorphosis be used as a generalized vertebrate model for thyroid function in screening batteries for detection of thyroid disrupters. However, it seems unlikely that such an assay would ever fully replace in vivo mammalian assays currently being validated for human health risk assessment: in its current form the amphibian metamorphosis screening assay would not provide capacity for reliably detecting other modes of endocrine-disrupting activity. Conversely, several candidate mammalian screening assays appear to offer robust capacity to detect a variety of modes of endocrine-disrupting activity, including thyroid activity. To assess whether omission of an amphibian metamorphosis assay from an in vivo screening battery would generate false negatives, the response of amphibian and mammalian assays to a variety known thyroid disrupters, as reported in peer-reviewed literature or government agency reports, was critically reviewed. Of the chemicals investigated from the literature selected (41), more had been tested in mammalian studies with thyroid-relevant endpoints (32) than in amphibian assays with appropriate windows of exposure and developmental endpoints (27). One chemical (methoxychlor) was reported to exhibit thyroid activity in an appropriate

  3. Bioactive Triterpenes from the Fungus Piptoporus betulinus

    Directory of Open Access Journals (Sweden)

    Zeyad Alresly

    2015-08-01

    Full Text Available Phytochemical investigation of the ethyl acetate extract of the fruiting bodies from the basidiomycete Piptoporus betulinus led to the isolation of a new bioactive lanostane triterpene identified as 3 b -acetoxy-16-hydroxy-24-oxo-5α-lanosta-8- ene-21-oic acid (1. In addition, ten known triterpenes, polyporenic acid A (5, polyporenic acid C (4, three derivatives of polyporenic acid A (8, 10, 11, betulinic acid (3, betulin (2, ergosterol peroxide (6, 9,11-dehydroergosterol peroxide (7, and fomefficinic acid (9, were also isolated from the fungus. All isolated compounds were tested for antimicrobial activity against some Gram-positive and Gram-negative bacteria as well as against a fungal strain. The new triterpene and some of the other compounds showed antimicrobial activity against Gram-positive bacteria.

  4. SYSTEMIC INFECTION AND RELATED FUNGUS: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Saha Rajsekhar

    2011-06-01

    Full Text Available A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds (British English: moulds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which are separate from plants, animals, and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. Many fungi play a crucial role in decomposition (breaking things down and returning nutrients to the soil. They are also used in medicine, an example is the antibiotic penicillin, as well as in industry and food preparation. In the present time the microbes are to be seen as disease causing organisms harming the mankind. The harm done by this community cannot be taken lightly as they are also useful in many ways. The above article is an effort to bring out the various fungal issued related to human.

  5. The unique myelopoiesis strategy of the amphibian Xenopus laevis.

    Science.gov (United States)

    Yaparla, Amulya; Wendel, Emily S; Grayfer, Leon

    2016-10-01

    Myeloid progenitors reside within specific hematopoietic organs and commit to progenitor lineages bearing megakaryocyte/erythrocyte (MEP) or granulocyte/macrophage potentials (GMP) within these sites. Unlike other vertebrates, the amphibian Xenopus laevis committed macrophage precursors are absent from the hematopoietic subcapsular liver and instead reside within their bone marrow. Presently, we demonstrate that while these frogs' liver-derived cells are unresponsive to recombinant forms of principal X. laevis macrophage (colony-stimulating factor-1; CSF-1) and granulocyte (CSF-3) growth factors, bone marrow cells cultured with CSF-1 and CSF-3 exhibit respectively archetypal macrophage and granulocyte morphology, gene expression and functionalities. Moreover, we demonstrate that liver, but not bone marrow cells possess erythropoietic capacities when stimulated with a X. laevis erythropoietin. Together, our findings indicate that X. laevis retain their MEP within the hematopoietic liver while sequestering their GMP to the bone marrow, thus marking a very novel myelopoietic strategy as compared to those seen in other jawed vertebrate species. PMID:27234705

  6. Autonomic control of cardiorespiratory interactions in fish, amphibians and reptiles.

    Science.gov (United States)

    Taylor, E W; Leite, C A C; Skovgaard, N

    2010-07-01

    Control of the heart rate and cardiorespiratory interactions (CRI) is predominantly parasympathetic in all jawed vertebrates, with the sympathetic nervous system having some influence in tetrapods. Respiratory sinus arrhythmia (RSA) has been described as a solely mammalian phenomenon but respiration-related beat-to-beat control of the heart has been described in fish and reptiles. Though they are both important, the relative roles of feed-forward central control and peripheral reflexes in generating CRI vary between groups of fishes and probably between other vertebrates. CRI may relate to two locations for the vagal preganglionic neurons (VPN) and in particular cardiac VPN in the brainstem. This has been described in representatives from all vertebrate groups, though the proportion in each location is variable. Air-breathing fishes, amphibians and reptiles breathe discontinuously and the onset of a bout of breathing is characteristically accompanied by an immediate increase in heart rate plus, in the latter two groups, a left-right shunting of blood through the pulmonary circuit. Both the increase in heart rate and opening of a sphincter on the pulmonary artery are due to withdrawal of vagal tone. An increase in heart rate following a meal in snakes is related to withdrawal of vagal tone plus a non-adrenergic-non-cholinergic effect that may be due to humoral factors released by the gut. Histamine is one candidate for this role. PMID:20464342

  7. Innervation of amphibian reproductive system. Histological and ultrastructural studies.

    Science.gov (United States)

    Cisint, Susana; Crespo, Claudia A; Medina, Marcela F; Iruzubieta Villagra, Lucrecia; Fernández, Silvia N; Ramos, Inés

    2014-10-01

    In the present study we describe for the first time in anuran amphibians the histological and ultrastructural characteristics of innervation in the female reproductive organs. The observations in Rhinella arenarum revealed the presence of nerve fibers located predominantly in the ovarian hilium and in the oviduct wall. In both organs the nerves fibers are placed near blood vessels and smooth muscles fibers. In the present study the histological observations were confirmed using antibodies against peripherin and neurofilament 200 proteins. Ultrastructural analyses demonstrated that the innervation of the reproductive organs is constituted by unmyelinated nerve fibers surrounded by Schwann cells. Axon terminals contain a population of small, clear, translucent vesicles that coexist with a few dense cored vesicles. The ultrastructural characteristics together with the immunopositive reaction to tyrosine hydroxylase of the nerve fibers and the type of synaptic vesicles present in the axon terminal would indicate that the reproductive organs of R. arenarum females are innervated by the sympathetic division of the autonomic nervous system. PMID:24882461

  8. Invasive reptiles and amphibians: global perspectives and local solutions

    Science.gov (United States)

    Reed, R.N.; Kraus, F.

    2010-01-01

    In the annals of invasive species biology, higher taxa such asmammals, plants and insects have received the lion’s shareof research attention, largely because many of these invadershave demonstrated a remarkable ability to degrade ecosys-tems and cause economic harm. Interest in invasive reptilesand amphibians (collectively ‘herpetofauna’, colloquially‘herps’) has historically lagged but is now garnering in-creased scrutiny as a result of their escalating pace ofinvasion. A few herpetofaunal invaders have received con-siderable attention in scientific and popular accounts, in-cluding the brown treesnakeBoiga irregularison Guam,Burmese pythonPython molurusin Florida, Coqu´ıEleutherodactylus coquiin Hawaii and cane toadBufomarinusin Australia. However, relatively few are aware ofmany emerging and potentially injurious herpetofaunalinvaders, such as Nile monitorsVaranus niloticusin Flor-ida, common kingsnakesLampropeltis getulain the CanaryIslands, boa constrictorsBoa constrictoron Aruba andCozumel, or a variety of giant constrictor snakes in PuertoRico. For the vast majority of the most commonlyintroduced species, real or potential impacts to nativeecosystems or human economic interests are poorly under-stood and incompletely explored; major pathways of intro-duction have only recently been elucidated, and effectivemanagement interventions have been limited (Kraus, 2009).

  9. Cryptosporidium parvum is not transmissible to fish, amphibians, or reptiles.

    Science.gov (United States)

    Graczyk, T K; Fayer, R; Cranfield, M R

    1996-10-01

    A recent report suggested that an isolate of Cryptosporidium parvum had established infections in fish, amphibians, and reptiles and raises concern that animals other than mammals might be a potential source of waterborne Cryptosporidium oocysts. To test this possibility, viable C. parvum oocysts, infectious for neonatal BALB/c mice, were delivered by gastric intubation to bluegill sunfish, poison-dart frogs, African clawed frogs, bearded dragon lizards, and corn snakes. Histological sections of the stomach, jejunum, ileum, and cloaca prepared from tissues collected on days 7 and 14 postinoculation (PI) were negative for Cryptosporidium developmental stages. However, inoculum-derived oocysts were detectable by fluorescein-labeled monoclonal antibody in feces of inoculated animals from day 1 to day 12 PI in fish and frogs, and up to day 14 PI in lizards. Snakes did not defecate for 14 days PI. Impression smears taken at necropsy on days 7 and 14 PI revealed C. parvum oocysts in the lumen of the cloaca of 2 fish and 1 lizard on day 7 PI only. Because tissue stages of the pathogen were not found, it appears that C. parvum was not heterologously transmitted to lower vertebrates. Under certain circumstances, however, such as after the ingestion of C. parvum-infected prey, lower vertebrates may disseminate C. parvum oocysts in the environment. PMID:8885883

  10. Plasticity of lung development in the amphibian, Xenopus laevis

    Directory of Open Access Journals (Sweden)

    Christopher S. Rose

    2013-10-01

    Contrary to previous studies, we found that Xenopus laevis tadpoles raised in normoxic water without access to air can routinely complete metamorphosis with lungs that are either severely stunted and uninflated or absent altogether. This is the first demonstration that lung development in a tetrapod can be inhibited by environmental factors and that a tetrapod that relies significantly on lung respiration under unstressed conditions can be raised to forego this function without adverse effects. This study compared lung development in untreated, air-deprived (AD and air-restored (AR tadpoles and frogs using whole mounts, histology, BrdU labeling of cell division and antibody staining of smooth muscle actin. We also examined the relationship of swimming and breathing behaviors to lung recovery in AR animals. Inhibition and recovery of lung development occurred at the stage of lung inflation. Lung recovery in AR tadpoles occurred at a predictable and rapid rate and correlated with changes in swimming and breathing behavior. It thus presents a new experimental model for investigating the role of mechanical forces in lung development. Lung recovery in AR frogs was unpredictable and did not correlate with behavioral changes. Its low frequency of occurrence could be attributed to developmental, physical and behavioral changes, the effects of which increase with size and age. Plasticity of lung inflation at tadpole stages and loss of plasticity at postmetamorphic stages offer new insights into the role of developmental plasticity in amphibian lung loss and life history evolution.

  11. Comparative studies of the secretome of fungus-growing ants

    DEFF Research Database (Denmark)

    Linde, Tore; Grell, Morten Nedergaard; Schiøtt, Morten;

    2009-01-01

    Leafcutter ants of the species Acromyrmex echinatior live in symbiosis with the fungus Leucoagaricus gongylophorus. The ants harvest fragments of leaves and carry them to the nest where they place the material on the fungal colony. The fungus secretes a wide array of proteins to degrade the leaves...... into nutrients that the ants can feed on. The focus of this study is to discover, characterize and compare the secreted proteins. In order to do so cDNA libraries are constructed from mRNA extracted from the fungus material. The most efficient technology to screen cDNA libraries selectively for...

  12. Fungal Garden Making inside Bamboos by a Non-Social Fungus-Growing Beetle

    OpenAIRE

    Toki, Wataru; Takahashi, Yukiko; Togashi, Katsumi

    2013-01-01

    In fungus-growing mutualism, it is indispensable for host animals to establish gardens of the symbiotic fungus as rapidly as possible. How to establish fungal gardens has been well-documented in social fungus-farming insects, whereas poorly documented in non-social fungus-farming insects. Here we report that the non-social, fungus-growing lizard beetle Doubledaya bucculenta (Coleoptera: Erotylidae: Languriinae) transmits the symbiotic yeast Wickerhamomyces anomalus from the ovipositor-associa...

  13. Morphophysiological Differences between the Metapleural Glands of Fungus-Growing and Non–Fungus-Growing Ants (Hymenoptera, Formicidae)

    OpenAIRE

    Vieira, Alexsandro Santana; Bueno, Odair Correa; Camargo-Mathias, Maria Izabel

    2012-01-01

    The metapleural gland is an organ exclusive to ants. Its main role is to produce secretions that inhibit the proliferation of different types of pathogens. The aim of the present study was to examine the morphophysiological differences between the metapleural gland of 3 non–fungus-growing ants of the tribes Ectatommini, Myrmicini, and Blepharidattini and that of 5 fungus-growing ants from 2 basal and 3 derived attine genera. The metapleural gland of the non–fungus-growing ants and the basal a...

  14. Radioecological studies of amphibians. Final report, September 15, 1968--July 21, 1977

    International Nuclear Information System (INIS)

    The radioecological role of amphibians in freshwater environments was studied. Three distinct aspects were studied: (1) the metabolism of radioecologically important radionuclides in amphibians; (2) the effect of acute doses of radiation on adult amphibians; and (3) the effect of chronic exposure to low radiation dose rates from radionuclide solutions on embryonic and larval amphibians. Twelve radioecologically important radionuclides were investigated in five different amphibian species. This involved tracing uptake from immersion, whole-body retention, and patterns of tissue and organ distribution. In most cases work was done at two different temperatures approximating winter and summer conditions. The radiosensitivity of the rough-skinned newt was determined over a very wide dose range. The same dose-response curve characteristic of mammals was found. However, survival times were greatly prolonged. The effect of environmental temperature on radiosensitivity was also studied. To ascertain evidence for repair mechanisms, a fractionated dose study was carried out. The effect of dose-rate was also studied. The effect of chronic low dose-rates from 134Cs solutions was traced for two frog species. Total dose was a function of time to metamorphosis, which differed by a factor of two in these species. In general, mortality levels exceeded those of controls only at 134Cs concentrations several orders of magnitude greater than MPC levels in drinking water

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Descriptive risk assessment of the effects of acidic deposition on Rocky Mountain amphibians

    Science.gov (United States)

    Corn, Paul Stephen; Vertucci, Frank A.

    1992-01-01

    We evaluated the risk of habitat acidification to the six species of amphibians that occur in the mountains of Colorado and Wyoming. Our evaluation included extrinsic environmental factors (habitat sensitivity and amount of acidic atmospheric deposition) and species-specific intrinsic factors (sensitivity to acid conditions, habitat preferences, and timing of breeding). Only one of 57 surveyed localities had both acid neutralizing capacity μeq/L and sulfate deposition >10 kg/ha/yr, extrinsic conditions with a possible risk of acidification. Amphibian breeding habitats in the Rocky Mountains do not appear to be sufficiently acidic to kill amphibian embryos. Some species breed in high-elevation vernal pools during snowmelt, and an acidic pulse during snowmelt may pose a risk to embryos of these species. However, the acidic pulse, if present, probably occurs before open water appears and before breeding begins. Although inherent variability of amphibian population size may make detection of declines from anthropogenic effects difficult, acidic deposition is unlikely to have caused the observed declines of Bufo boreas and Rana pipiens in Colorado and Wyoming. Amphibians in the Rocky Mountains are not likely to be at risk with acidification inputs at present levels.

  17. Low thermal tolerances of stream amphibians in the Pacific Northwest: Implications for riparian and forest management

    Science.gov (United States)

    Bury, R.B.

    2008-01-01

    Temperature has a profound effect on survival and ecology of amphibians. In the Pacific Northwest, timber harvest is known to increase peak stream temperatures to 24??C or higher, which has potential to negatively impact cold-water stream amphibians. I determined the Critical Thermal Maxima (CT max) for two salamanders that are endemic to the Pacific Northwest. Rhyacotriton variegatus larvae acclimated at 10??C had mean CTmax of 26.7 ?? 0.7 SD??C and adults acclimated at 11??C had mean CT max of 27.9 ?? 1.1??C. These were among the lowest known values for any amphibian. Values were significantly higher for larval Dicamptodon tenebrosus acclimated at 14??C (x = 29.1 ?? 0.2??C). Although the smallest R. variegatus had some of the lowest values, size of larvae and adults did not influence CTmax in this species. Current forest practices retain riparian buffers along larger fish-bearing streams; however, such buffers along smaller headwaters and non-fish bearing streams may provide favorable habitat conditions for coldwater-associated species in the Pacific Northwest. The current study lends further evidence to the need for protection of Northwest stream amphibians from environmental perturbations. Forest guidelines that include riparian buffer zones and configurations of upland stands should be developed, while monitoring amphibian responses to determine their success. ?? 2008 Brill Academic Publishers.

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

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    DEFF Research Database (Denmark)

    Semenova, Tatyana; Hughes, David Peter; Boomsma, Jacobus Jan;

    2011-01-01

    of evolutionary more derived fungal symbionts. This notion is also supported by buffering capacities of fungus gardens at pH 5.2 being remarkably high, and suggests that the fungal symbiont actively helps to maintain garden acidity at this specific level. Metalloproteinases dominated the activity profiles....... Conclusions: Proteinase pH optima and buffering capacities of fungal symbionts appear to have evolved remarkable adaptations to living in obligate symbiosis with farming ants. Although the functional roles of serine and metalloproteinases in fungus gardens are unknown, the differential production...... hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results: We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing...

  1. Solubilization of lignin by the ruminal anaerobic fungus Neocallimastix patriciarum.

    OpenAIRE

    McSweeney, C S; Dulieu, A; Katayama, Y; Lowry, J B

    1994-01-01

    The ability of the ruminal anaerobic phycomycete Neocallimastix patriciarum to digest model lignin compounds and lignified structures in plant material was studied in batch culture. The fungus did not degrade or transform model lignin compounds that were representative of the predominant intermonomer linkages in lignin, nor did it solubilize acid detergent lignin that had been isolated from spear grass. In a stem fraction of sorghum, 33.6% of lignin was apparently solubilized by the fungus. S...

  2. Contributions to the study of Pseudopeziza trifolii (Bernh. Fuck. fungus

    Directory of Open Access Journals (Sweden)

    Olga PALL

    1966-08-01

    Full Text Available The present paper communicates the results of the laboratory experiments concerning the behaviour of the Pseudopeziza trifolii (Bernh. Fuck. fungus that produces the clover brown leaf spot, in different culture mediums. The mycelium of the fungus develops at its best on the peptone-glucose-agar medium. The appearance of pycnides of Sporonema phacidioides Desm. type in vitro, has been reported for the fourth time in Romania especially developing on the potatoe-dextrosis-agar and plum-agar mediums.

  3. Isolation and Identification of Glucoamylase Producer Fungus from Sago Hampas

    OpenAIRE

    Alfi Asben; Tun Tedja Irawadi2)

    2013-01-01

    Waste of sago processing, notably hampas (ela) still contains sago starch is waste that has not been utilized optimally yet  and causing pollution. Isolation and identification of glucoamylase producer fungus of sago hampas waste  were aims to obtain isolates that have gluco-amylolytic properties, and to know glucoamylase activity of selected fungus isolates after grown on artificial medium.  Indegeneous isolates that can produced glucoamylase will be use to get sugar hidrolysate from starch ...

  4. New aquatic sites of the fungus Sommerstorffia spinosa

    OpenAIRE

    Bazyli Czeczuga; Bożena Mazalska; Mirosława Orłowska

    2014-01-01

    When studying zoosporic fungi in the waters of northeastern Poland tbe authors found new sites of a rare fungus - Sommerstorffia spinosa Arnaudow. Its growth was observed in water samples collected from limnologically different reservoirs, from the spring Jaroszówka, the oligotrophic type (Lake Białe), through mesotrophic (Lake Wigry) to the polytrophic type (pond Fosa with high content of hydrogen sulphide under ice cover). This fungus was also found in the river Biała, which flowing through...

  5. ADR: An atypical presentation of rare dematiaceous fungus

    Directory of Open Access Journals (Sweden)

    J Karthika

    2014-01-01

    Full Text Available The association of fungus in allergic fungal rhino sinusitis has been around 200 times in the world literature. As per the available literature, the most common agent identified so far appears to be ASPERGILLUS, though the condition is increasingly associated with Dematiaceous fungi. Here we report for the first time the presence of unusual fungus in allergic rhino sinusitis, which has not been reported so far.

  6. Anthraquinones from the Fungus Dermocybe sanguinea as Textile Dyes

    OpenAIRE

    RÀisÀnen, Riikka

    2009-01-01

    This study is based on the multidiciplinary approach of using natural colorants as textile dyes. The author was interested in both the historical and traditional aspects of natural dyeing as well as the modern industrial applications of the pure natural compounds. In the study, the anthraquinone compounds were isolated as aglycones from the ectomycorrhizal fungus Dermocybe sanguinea. The endogenous beta-glucosidase of the fungus was used to catalyse the hydrolysis of the O-glycosyl linka...

  7. New Development Trend of Edible Fungus Industry in China

    OpenAIRE

    Lu, Min; Li, Yu

    2012-01-01

    We elaborate support system of edible fungus industry from outlook on ecological economic development, legislation and standardization of variety approval, multiple-function innovation platform of industrial development research, and perfect talent cultivation and education system. Besides, we analyze the development trend of edible fungus industry from competitive advantages, position and role in national food security, industrial development trend driven by internal demand. diversified indu...

  8. High amphibian diversity related to unexpected environmental values in a biogeographic transitional area in north-western Mexico

    NARCIS (Netherlands)

    Serrano, J.M.; Berlanga-Robles, C.A.; Ruiz-Luna, A.

    2014-01-01

    Amphibian diversity and distribution patterns in Sinaloa state (north-western Mexico) were assessed from the Global Amphibian Assessment database (GAA-2010). A geographic information system (GIS) was used to evaluate diversity based on distribution maps of 41 species, associated with environmental d

  9. Solubilization of diabase and phonolite dust by filamentous fungus

    Directory of Open Access Journals (Sweden)

    Juliana Andréia Vrba Brandão

    2014-10-01

    Full Text Available The objective of this study was to evaluate the effect of the fungus Aspergillus niger strain CCT4355 in the release of nutrients contained in two types of rock powder (diabase and phonolite by means of in vitro solubilization trials. The experimental design was completely randomized in a 5 x 4 factorial design with three replications. It was evaluated five treatments (phonolite dust + culture medium; phonolite dust + fungus + culture medium; diabase powder + culture medium; diabase powder + fungus + culture medium and fungus + culture medium and four sampling dates (0, 10, 20 and 30 days. Rock dust (0.4% w/v was added to 125 mL Erlenmeyer flasks containing 50 mL of liquid culture medium adapted to A. niger. The flasks were incubated at 30°C for 30 days, and analysis of pH (in water, titratable acidity, and concentrations of soluble potassium, calcium, magnesium, zinc, iron and manganese were made. The fungus A. niger was able to produce organic acids that solubilized ions. This result indicates its potential to alter minerals contained in rock dust, with the ability to interact in different ways with the nutrients. A significant increase in the amount of K was found in the treatment with phonolite dust in the presence of the fungus. The strain CCT4355 of A. niger can solubilize minerals contained in these rocks dust.

  10. Characterizing the width of amphibian movements during postbreeding migration.

    Science.gov (United States)

    Coster, Stephanie S; Veysey Powell, Jessica S; Babbitt, Kimberly J

    2014-06-01

    Habitat linkages can help maintain connectivity of animal populations in developed landscapes. However, the lack of empirical data on the width of lateral movements (i.e., the zigzagging of individuals as they move from one point to point another) makes determining the width of such linkages challenging. We used radiotracking data from wood frogs (Lithobates sylvaticus) and spotted salamanders (Ambystoma maculatum) in a managed forest in Maine (U.S.A.) to characterize movement patterns of populations and thus inform planning for the width of wildlife corridors. For each individual, we calculated the polar coordinates of all locations, estimated the vector sum of the polar coordinates, and measured the distance from each location to the vector sum. By fitting a Gaussian distribution over a histogram of these distances, we created a population-level probability density function and estimated the 50th and 95th percentiles to determine the width of lateral movement as individuals progressed from the pond to upland habitat. For spotted salamanders 50% of lateral movements were ≤13 m wide and 95% of movements were ≤39 m wide. For wood frogs, 50% of lateral movements were ≤17 m wide and 95% of movements were ≤ 51 m wide. For both species, those individuals that traveled the farthest from the pond also displayed the greatest lateral movement. Our results serve as a foundation for spatially explicit conservation planning for pond-breeding amphibians in areas undergoing development. Our technique can also be applied to movement data from other taxa to aid in designing habitat linkages. PMID:24423254

  11. The envelopes of amphibian oocytes: physiological modifications in Bufo arenarum

    Directory of Open Access Journals (Sweden)

    Sánchez Mercedes

    2003-02-01

    Full Text Available Abstract A characterization of the Amphibian Bufo arenarum oocyte envelope is presented. It was made in different functional conditions of the oocyte: 1 when it has been released into the coelomic cavity during ovulation (surrounded by the coelomic envelope, (CE, 2 after it has passed through the oviduct and is deposed (surrounded by the viteline envelope, (VE, and 3 after oocyte activation (surrounded by the fertilization envelope, (FE. The characterization was made by SDS-PAGE followed by staining for protein and glycoproteins. Labeled lectins were used to identify glycosidic residues both in separated components on nitrocellulose membranes or in intact oocytes and embryos. Proteolytic properties of the content of the cortical granules were also analyzed. After SDS-PAGE of CE and VE, a different protein pattern was observed. This is probably due to the activity of a protease present in the pars recta of the oviduct. Comparison of the SDS-PAGE pattern of VE and FE showed a different mobility for one of the glycoproteins, gp75. VE and FE proved to have different sugar residues in their oligosaccharide chains. Mannose residues are only present in gp120 of the three envelopes. N-acetyl-galactosamine residues are present in all of the components, except for gp69 in the FE. Galactose residues are present mainly in gp120 of FE. Lectin-binding assays indicate the presence of glucosamine, galactose and N-acetyl galactosamine residues and the absence (or non-availability of N-acetyl-glucosamine or fucose residues on the envelopes surface. The cortical granule product (CGP shows proteolytic activity on gp75 of the VE.

  12. Amphibians as Model Organisms for Studying the Dynamics of Eukaryote Genetic Material Architecture

    Directory of Open Access Journals (Sweden)

    Burlibaşa, L.

    2005-06-01

    Full Text Available Amphibians have played a key role in the elucidation of the mechanisms of early development over the last century. Much of our knowledge about the mechanisms of vertebrate early development comes from studies using Xenopus laevis. Xenopus sp. is a major contributor to our understanding of cell biological and biochemical processes, including: (1 chromosome replication; (2 chromatin, cytoskeleton and nuclear assembly; (3 cell cycle progression and (4 intracellular signaling. Amphibian embryos remained the embryos of choice for experimental embryology for many decades. European embryologists used predominantly urodele embryos (such as Triturus and embryos of the frog Rana temporaria, which is related to the North American species Rana pipiens. Using light, fluorescence, transmission electron microscopy (TEM and molecular investigations, some peculiar aspects of chromatin and chromosome organization and evolution in oogenesis and spermatogenesis of amphibians were investigated. We have focused our investigations on dynamics of the chromatin structure in different stages of development.

  13. Challenges in evaluating the impact of the trade in amphibians and reptiles on wild populations

    Science.gov (United States)

    Schlaepfer, Martin A.; Hoover, Craig; Dodd, C. Kenneth, Jr.

    2005-01-01

    Amphibians and reptiles are taken from the wild and sold commercially as food, pets, and traditional medicines. The overcollecting of some species highlights the need to assess the trade and ensure that it is not contributing to declines in wild populations. Unlike most countries, the United States tracks the imports and exports of all amphibians and reptiles. Records from 1998 to 2002 reveal a US trade of several million wild-caught amphibians and reptiles each year, although many shipments are not recorded at the species level. The magnitude and content of the global commercial trade carries even greater unknowns. The absence of accurate trade and biological information for most species makes it difficult to establish whether current take levels are sustainable. The void of information also implies that population declines due to overcollecting could be going undetected. Policy changes to acquire baseline biological information and ensure a sustainable trade are urgently needed.

  14. 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

    Aim We explore the relationship between current European distributions of amphibian and reptile species and observed climate, and project species potential distributions into the future. Potential impacts of climate warming are assessed by quantifying the magnitude and direction of modelled...... distributional shifts for every species. In particular we ask, first, what proportion of amphibian and reptile species are projected to lose and gain suitable climate space in the future? Secondly, do species projections vary according to taxonomic, spatial or environmental properties? And thirdly, what climate...... of forecasts is then used to group linearly covarying projections into clusters with reduced inter-model variability. Results We show that a great proportion of amphibian and reptile species are projected to expand distributions if dispersal is unlimited. This is because warming in the cooler...

  15. Impact of otter (Lutra lutra predation on amphibians in temporary ponds in Southern Spain

    Directory of Open Access Journals (Sweden)

    Dan Cogălniceanu

    2010-12-01

    Full Text Available We report the observation of an event of mortality of ribbed newts (Pleurodeles waltl and Iberian spadefoot toads (Pelobates cultripes due to predation by a pair of otters (Lutra lutra in a temporary pond complex in southern Spain. The peculiar predation mode on ribbed newts, with extraction of soft organs through an incision in the upper part of the thorax, may result in an under estimate of the importance of this species in the diet of otters. The high number of dead amphibians killed by two otters in only several hours suggests that the presence of these predators may pose a serious threat to amphibian populations. The risk is especially high in arid areas, with few ponds, synchronous reproductive migration, and high density of animals. We consider that measures promoting the conservation and population and range increase of otters might have a negative impact on amphibians.

  16. Raising awareness of amphibian Chytridiomycosis will not alienate ecotourists visiting Madagascar.

    Science.gov (United States)

    Wollenberg, Katharina C; Jenkins, Richard K B; Randrianavelona, Roma; Ralisata, Mahefa; Rampilamanana, Roseline; Ramanandraibe, Andrianirina; Ravoahangimalala, Olga Ramilijaona; Vences, Miguel

    2010-06-01

    Chytridiomycosis (Bd) is contributing to amphibian extinctions worldwide but has so far not been detected in Madagascar. The high likelihood for Bd to spread to the island and efface this amphibian diversity and endemism hotspot requires respective conservation policies to be developed. Bd could be introduced by the large number of tourists that visit protected areas; therefore, increasing awareness among tourists and encouraging them to participate in safety measures should be a priority conservation action. However, concerns have been raised that tourists would not be able to distinguish between an amphibian disease harmless to humans and emerging diseases that would imply a danger for human health, invoking a negative image of Madagascar as an ecotourism destination. We evaluated whether informing tourists about this infectious animal disease would cause health scare and diminish trip satisfaction. Based on 659 respondents we found that most ecotourists favored to be informed about Bd and were proactive about participating in prevention measures, refuting previous concerns. PMID:20517634

  17. 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.

  18. Amphibian Research and Monitoring Initiative (ARMI): a successful start to a national program in the United States

    Science.gov (United States)

    Muths, E.; Jung, R.E.; Bailey, L.L.; Adams, M.J.; Corn, P.S.; Dodd, C.K., Jr.; Fellers, G.M.; Sandinski, W.J.; Schwalbe, C.R.; Walls, S.C.; Fisher, R.N.; Gallant, A.L.; Battaglin, W.A.; Green, D.E.

    2005-01-01

    Most research to assess amphibian declines has focused on local-scale projects on one or a few species. The Amphibian Research and Monitoring Initiative (ARMI) is a national program in the United States mandated by congressional directive and implemented by the U.S. Department of the Interior (specifically the U.S. Geological Survey, USGS). Program goals are to monitor changes in populations of amphibians across U.S. Department of the Interior lands and to address research questions related to amphibian declines using a hierarchical framework of base-, mid- and apex-level monitoring sites. ARMI is currently monitoring 83 amphibian species (29% of species in the U.S.) at mid- and apex-level areas. We chart the progress of this 5-year-old program and provide an example of mid-level monitoring from 1 of the 7 ARMI regions.

  19. Where have all the tadpoles gone? Individual genetic tracking of amphibian larvae until adulthood.

    Science.gov (United States)

    Ringler, Eva; Mangione, Rosanna; Ringler, Max

    2015-07-01

    Reliably marking larvae and reidentifying them after metamorphosis is a challenge that has hampered studies on recruitment, dispersal, migration and survivorship of amphibians for a long time, as conventional tags are not reliably retained through metamorphosis. Molecular methods allow unique genetic fingerprints to be established for individuals. Although microsatellite markers have successfully been applied in mark-recapture studies on several animal species, they have never been previously used in amphibians to follow individuals across different life cycle stages. Here, we evaluate microsatellites for genetic across-stages mark-recapture studies in amphibians and test the suitability of available software packages for genotype matching. We sampled tadpoles of the dendrobatid frog Allobates femoralis, which we introduced on a river island in the Nature Reserve 'Les Nouragues' in French Guiana. In two subsequent recapture sessions, we searched for surviving juveniles and adults, respectively. All individuals were genotyped at 14 highly variable microsatellite loci, which yielded unique genetic fingerprints for all individuals. We found large differences in the identification success of the programs tested. The pairwise-relatedness-based approach, conducted with the programs kingroup or ML-Relate, performed best with our data set. Matching ventral patterns of juveniles and adult individuals acted as a control for the reliability of the genetic identification. Our results demonstrate that microsatellite markers are a highly powerful tool for studying amphibian populations on an individual basis. The ability to individually track amphibian tadpoles throughout metamorphosis until adulthood will be of substantial value for future studies on amphibian population ecology and evolution. PMID:25388775

  20. Land use explains the distribution of threatened New World amphibians better than climate.

    Directory of Open Access Journals (Sweden)

    Fernanda Thiesen Brum

    Full Text Available BACKGROUND: We evaluated the direct and indirect influence of climate, land use, phylogenetic structure, species richness and endemism on the distribution of New World threatened amphibians. METHODOLOGY/PRINCIPAL FINDINGS: We used the WWF's New World ecoregions, the WWFs amphibian distributional data and the IUCN Red List Categories to obtain the number of threatened species per ecoregion. We analyzed three different scenarios urgent, moderate, and the most inclusive scenario. Using path analysis we evaluated the direct and indirect effects of climate, type of land use, phylogenetic structure, richness and endemism on the number of threatened amphibians in New World ecoregions. In all scenarios we found strong support for direct influences of endemism, the cover of villages and species richness on the number of threatened species in each ecoregion. The proportion of wild area had indirect effects in the moderate and the most inclusive scenario. Phylogenetic composition was important in determining the species richness and endemism in each ecoregion. Climate variables had complex and indirect effects on the number of threatened species. CONCLUSION/SIGNIFICANCE: Land use has a more direct influence than climate in determining the distribution of New World threatened amphibians. Independently of the scenario analyzed, the main variables influencing the distribution of threatened amphibians were consistent, with endemism having the largest magnitude path coefficient. The importance of phylogenetic composition could indicate that some clades may be more threatened than others, and their presence increases the number of threatened species. Our results highlight the importance of man-made land transformation, which is a local variable, as a critical factor underlying the distribution of threatened amphibians at a biogeographic scale.

  1. 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

    2016-01-01

    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.

  2. 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 and...... are disproportionately more affected by one or multiple threat factors than areas with low richness. Amphibian declines are likely to accelerate in the twenty-first century, because multiple drivers of extinction could jeopardize their populations more than previous, mono-causal, assessments have...

  3. A highly divergent picornavirus in an amphibian, the smooth newt (Lissotriton vulgaris).

    Science.gov (United States)

    Reuter, Gábor; Boros, Ákos; Tóth, Zoltán; Gia Phan, Tung; Delwart, Eric; Pankovics, Péter

    2015-09-01

    Genetically highly divergent picornavirus (Newt/2013/HUN, KP770140) was detected using viral metagenomics in faecal samples of free-living smooth newts (Lissotriton vulgaris). Newt picornavirus was identified by reverse transcription-polymerase chain reaction (RT-PCR) in six (25 %) of the 24 samples originating from individuals caught in two out of the six investigated natural ponds in Hungary. The first picornavirus in amphibians expands the host range of members of the Picornaviridae, and opens a new research field in picornavirus evolution in lower vertebrates. Newt picornavirus represents a novel species in a novel genus within the family Picornaviridae, provisionally named genus Ampivirus (amphibian picornavirus). PMID:26018961

  4. Creation of temporary ponds for amphibians in northern and central Europe

    OpenAIRE

    Briggs, Lars

    2001-01-01

    More than 4000 ponds have been created or restored in Denmark since 1985 as part of a large-scale pond-digging programme to protect endangered amphibians in particular and pond flora and fauna in general. Most ponds are created on private land with public financing. The programme was triggered by, among other factors, a drastic decline in amphibian populations in Denmark between 1940 and 1980. However, in recent years there has been an increased awareness in Denmark that temporary ponds are i...

  5. Cloning and Transcriptional Activation of the Vitamin D Receptor (Amphibians)1

    OpenAIRE

    GÜZEY, Meral

    1999-01-01

    The vitamin D receptor (VDR), a member of the nuclear receptor superfamily, is an integral part of the body's calcium regulatory system. Mammalian and avian VDR genes were isolated, sequenced and characterized. In this study we cloned the vitamin D receptor from amphibians. We received a cDNA library prepared from amphibian (frog) tissues and prepared a cDNA probe based on the avian VDR. We screened the library and located the positive clones. Complete structure of VDR gene has been comp...

  6. Isolated Polynucleotides and Methods of Promoting a Morphology in a Fungus

    Science.gov (United States)

    Lasure, Linda L. [Fall City, WA; Dai, Ziyu [Richland, WA

    2008-10-21

    The invention includes isolated polynucleotide molecules that are differentially expressed in a native fungus exhibiting a first morphology relative to the native fungus exhibiting a second morphology. The invention includes a method of enhancing a bioprocess utilizing a fungus. A transformed fungus is produced by transforming a fungus with a recombinant polynucleotide molecule. The recombinant polynucleotide molecule contains an isolated polynucleotide sequence linked operably to a promoter. The polynucleotide sequence is expressed to promote a first morphology. The first morphology of the transformed fungus enhances a bioprocess relative to the bioprocess utilizing a second morphology.

  7. Amphibian breeding and climate change: The importance of snow in the mountains

    Science.gov (United States)

    Corn, P. Stephen

    2003-01-01

    The breeding phenologies of ectotherms are inextricably linked to weather, and amphibians in some temperate locations may have been breeding earlier in recent years in response to warmer spring temperatures (Beebee 1995: Forchhammer et al. 1998; Gibbs & Breisch 2001). Directional change in the timing of breeding resulting from climate change may have consequences for the fitness of individuals and may affect the persistence of amphibian populations (Ovaska 1997: Donnelly & Crump 1998). Blaustein et al. (2001) contribute valuable information to the small, but growing, data set of long-term observations of amphibian breeding phenology. As in other studies, Blaustein et al. found a significant relationship between air temperature and phenology, with earlier breeding associated with warmer air temperatures for boreal toads (Bufo boreas) and Cascades frogs (Rana cascadae) in Oregon and for spring peepers (Pseudacris crucifer) in Michigan. Contrary to other studies, however, there was no trend toward earlier breeding relative to year for any of these species or for Fowler's toads (B. fouleri) in Ontario. These results are important in demonstrating that changes in breeding phenology due to climate change are not universal among amphibians.

  8. Amphibian Metamorphosis: A Sensitive Life Stage to Chemical and Non-chemical Stressors

    Science.gov (United States)

    Amphibian metamorphosis is a dynamic period of post-embryonic development which transforms the larval anuran into the juvenile. The body structure is remodeled through a variety of processes which may be perturbed by exposure to chemicals as well as other environmental stressors....

  9. Framework for assessment and monitoring of amphibians and reptiles in the Lower Urubamba region, Peru.

    Science.gov (United States)

    Icochea, Javier; Quispitupac, Eliana; Portilla, Alfredo; Ponce, Elias

    2002-05-01

    Populations of amphibians and reptiles are experiencing new or increasing threats to their survival. Many of these threats are directly attributable to human activity and resource development. This presents the increasing need for worldwide amphibian and reptile assessments and effective, standardized monitoring protocols. Adaptive management techniques can assist managers in identifying and mitigating threats to amphibian and reptile populations. In 1996, Shell Prospecting and Development, Peru initiated a natural gas exploration project in the rainforest of southeastern Peru. The Smithsonian Institution's Monitoring and Assessment of Biodiversity Program worked closely with Shell engineers and managers to establish an adaptive management program to protect the region's biodiversity. In this manuscript, we discuss the steps we took to establish an adaptive management program for amphibian and reptile communities in the region. We define and outline the conceptual issues involved in establishing an assessment and monitoring program, including setting objectives, evaluating the results and making appropriate decisions. We also provide results from the assessment and discuss the appropriateness and effectiveness of protocols and criteria used for selecting species to monitor. PMID:12125750

  10. A mathematical model of amphibian skin epithelium with two types of transporting cellular units

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1985-01-01

    A computer model of ion transport across amphibian skin epithelium containing two types of cellular units, their relative number and sizes, and a paracellular pathway has been developed. The two cellular units are, a large Na+ transporting compartment representing the major epithelium from stratum...

  11. Emerging Pathogen in Wild Amphibians and Frogs (Rana catesbeiana) Farmed for International Trade

    OpenAIRE

    Mazzoni, Rolando; Cunningham, Andrew A.; Daszak, Peter; Apolo, Ada; Perdomo, Eugenio; Speranza, Gustavo

    2003-01-01

    Chytridiomycosis is an emerging disease responsible for global decline and extinction of amphibians. We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade. Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.

  12. Carotenoids and amphibians: effects on life history and susceptibility to the infectious pathogen, Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Cothran, Rickey D; Gervasi, Stephanie S; Murray, Cindy; French, Beverly J; Bradley, Paul W; Urbina, Jenny; Blaustein, Andrew R; Relyea, Rick A

    2015-01-01

    Carotenoids are considered beneficial nutrients because they provide increased immune capacity. Although carotenoid research has been conducted in many vertebrates, little research has been done in amphibians, a group that is experiencing global population declines from numerous causes, including disease. We raised two amphibian species through metamorphosis on three carotenoid diets to quantify the effects on life-history traits and post-metamorphic susceptibility to a fungal pathogen (Batrachochytrium dendrobatidis; Bd). Increased carotenoids had no effect on survival to metamorphosis in gray treefrogs (Hyla versicolor) but caused lower survival to metamorphosis in wood frogs [Lithobates sylvaticus (Rana sylvatica)]. Increased carotenoids caused both species to experience slower development and growth. When exposed to Bd after metamorphosis, wood frogs experienced high mortality, and the carotenoid diets had no mitigating effects. Gray treefrogs were less susceptible to Bd, which prevented an assessment of whether carotenoids could mitigate the effects of Bd. Moreover, carotenoids had no effect on pathogen load. As one of only a few studies examining the effects of carotenoids on amphibians and the first to examine potential interactions with Bd, our results suggest that carotenoids do not always serve amphibians in the many positive ways that have become the paradigm in other vertebrates. PMID:27293690

  13. Temperature-dependent acute toxicity of methomyl pesticide on larvae of 3 Asian amphibian species.

    Science.gov (United States)

    Lau, Edward Tak Chuen; Karraker, Nancy Elizabeth; Leung, Kenneth Mei Yee

    2015-10-01

    Relative to other animal taxa, ecotoxicological studies on amphibians are scarce, even though amphibians are experiencing global declines and pollution has been identified as an important threat. Agricultural lands provide important habitats for many amphibians, but often these lands are contaminated with pesticides. The authors determined the acute toxicity, in terms of 96-h median lethal concentrations, of the carbamate pesticide methomyl on larvae of 3 Asian amphibian species, the Asian common toad (Duttaphrynus melanostictus), the brown tree frog (Polypedates megacephalus), and the marbled pygmy frog (Microhyla pulchra), at 5 different temperatures (15 °C, 20 °C, 25 °C, 30 °C, and 35 °C) to examine the relationships between temperature and toxicity. Significant interspecific variation in methomyl sensitivity and 2 distinct patterns of temperature-dependent toxicity were found. Because high proportions of malformation among the surviving tadpoles were observed, a further test was carried out on the tree frog to determine effect concentrations using malformation as the endpoint. Concentrations as low as 1.4% of the corresponding 96-h median lethal concentrations at 25 °C were sufficient to cause malformation in 50% of the test population. As the toxicity of pesticides may be significantly amplified at higher temperatures, temperature effects should not be overlooked in ecotoxicological studies and derivation of safety limits in environmental risk assessment and management. PMID:25959379

  14. Energy, water and large-scale patterns of reptile and amphibian species richness in Europe

    Science.gov (United States)

    Rodríguez, Miguel Á.; Belmontes, Juan Alfonso; Hawkins, Bradford A.

    2005-07-01

    We used regression analyses to examine the relationships between reptile and amphibian species richness in Europe and 11 environmental variables related to five hypotheses for geographical patterns of species richness: (1) productivity; (2) ambient energy; (3) water-energy balance, (4) habitat heterogeneity; and (5) climatic variability. For reptiles, annual potential evapotranspiration (PET), a measure of the amount of atmospheric energy, explained 71% of the variance, with variability in log elevation explaining an additional 6%. For amphibians, annual actual evapotranspiration (AET), a measure of the joint availability of energy and water in the environment, and the global vegetation index, an estimate of plant biomass generated through satellite remote sensing, both described similar proportions of the variance (61% and 60%, respectively) and had partially independent effects on richness as indicated by multiple regression. The two-factor environmental models successfully removed most of the statistically detectable spatial autocorrelation in the richness data of both groups. Our results are consistent with reptile and amphibian environmental requirements, where the former depend strongly on solar energy and the latter require both warmth and moisture for reproduction. We conclude that ambient energy explains the reptile richness pattern, whereas for amphibians a combination of water-energy balance and productivity best explain the pattern.

  15. 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.

  16. Alternative Conceptions in Animal Classification Focusing on Amphibians and Reptiles: A Cross-Age Study

    Science.gov (United States)

    Yen, Chiung-Fen; Yao, Tsung-Wei; Chiu, Yu-Chih

    2004-01-01

    This study examined students' alternative conceptions of reptiles and amphibians and the extent to which these conceptions remain intact through the elementary (grades 4 and 6), junior, and senior high school years. We administered multiple-choice and free-response instruments to a total of 513 students and interviewed at least 20 students at each…

  17. ROLE OF AMPHIBIANS AND REPTILES IN CREATION OF AN ECOLOGICAL BUFFER AGAINST TECHNOGENIC POLLUTION

    OpenAIRE

    V. L. Bulakhov; V. Y. Gasso

    2008-01-01

    It has shown that fossorial activity of common spadefoot Pelobates fuscus (Laurenti, 1768) under conditions of heavy metals pollution of soils is able to reduce the level of the metals in soil. Tropho-metabolic activity (faeces excretion) of amphibians ( P. fuscus ) and reptiles (sand lizard Lacerta agilis Linnaeus, 1758) decreases the content of heavy metals in soils.

  18. The potential effects of climate change on amphibian distribution, range fragmentation and turnover in China.

    Science.gov (United States)

    Duan, Ren-Yan; Kong, Xiao-Quan; Huang, Min-Yi; Varela, Sara; Ji, Xiang

    2016-01-01

    Many studies predict that climate change will cause species movement and turnover, but few have considered the effect of climate change on range fragmentation for current species and/or populations. We used MaxEnt to predict suitable habitat, fragmentation and turnover for 134 amphibian species in China under 40 future climate change scenarios spanning four pathways (RCP2.6, RCP4.5, RCP6 and RCP8.5) and two time periods (the 2050s and 2070s). Our results show that climate change may cause a major shift in spatial patterns of amphibian diversity. Amphibians in China would lose 20% of their original ranges on average; the distribution outside current ranges would increase by 15%. Suitable habitats for over 90% of species will be located in the north of their current range, for over 95% of species in higher altitudes (from currently 137-4,124 m to 286-4,396 m in the 2050s or 314-4,448 m in the 2070s), and for over 75% of species in the west of their current range. Also, our results predict two different general responses to the climate change: some species contract their ranges while moving westwards, southwards and to higher altitudes, while others expand their ranges. Finally, our analyses indicate that range dynamics and fragmentation are related, which means that the effects of climate change on Chinese amphibians might be two-folded. PMID:27547522

  19. 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.

  20. Inefficiency and Bias of Search Engines in Retrieving References Containing Scientific Names of Fossil Amphibians

    Science.gov (United States)

    Brown, Lauren E.; Dubois, Alain; Shepard, Donald B.

    2008-01-01

    Retrieval efficiencies of paper-based references in journals and other serials containing 10 scientific names of fossil amphibians were determined for seven major search engines. Retrievals were compared to the number of references obtained covering the period 1895-2006 by a Comprehensive Search. The latter was primarily a traditional…

  1. 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. PMID:26765086

  2. First report of freshwater leech Helobdella stagnalis (Rhyncobdellida: Glossiphoniidae as a parasite of an anuran amphibian

    Directory of Open Access Journals (Sweden)

    Rocco Tiberti

    2010-12-01

    Full Text Available The authors describe the first case of parasitism on anuran amphibian, Rana temporaria, by the freshwater leech Helobdella stagnalis, in a mountainous area of northwestern Italy. The presence of skin abrasions and haemorrhages attributable to leech attack discards the hypothesis of a simple phoretic relationship between leech and frog.

  3. Utilizing In Vitro Derived Metabolic Rate Constants to Inform Pesticide Body Burdens in Amphibians

    Science.gov (United States)

    Over 2.4 billion kilograms of pesticides have been used worldwide in preventing diseases, dealing with nuisance animals and aiding in crop management Although pesticides are used to control insects and diseases, exposure to non-target species frequently occurs.Amphibians are impo...

  4. Expansion of amphibian intronless interferons revises the paradigm for interferon evolution and functional diversity

    Science.gov (United States)

    Interferons (IFNs) are key cytokines identified in vertebrates, and evolutionary dominance of intronless IFN genes in amniotes is a signature event in IFN evolution. For the first time, we show that the emergence and expansion of intronless IFN genes is evident in amphibians, shown by 24-37 intronle...

  5. Design and Management Criteria for Fish, Amphibian, and Reptile Communities Within Created Agricultural Wetlands

    Science.gov (United States)

    Design and management criteria for created agricultural wetlands in the midwestern United States typically focus on maximizing the ability to process agricultural runoff. Ecological benefits for fish, amphibian, and reptiles are often secondary considerations. One example of this water quality focu...

  6. Type specimens of amphibians in the National Museum of Natural History, Leiden, The Netherlands

    NARCIS (Netherlands)

    Gasso Miracle, M.E.; Hoek Ostende, van den L.W.; Arntzen, J.W.

    2007-01-01

    The amphibian type specimens held in the National Museum of Natural History in Leiden are listed. A total of 775 type specimens representing 143 taxon names were encountered. The list provides the original name, the original publication date, pagination and illustrations, current name, type locality

  7. Association of amphibians with attenuation of ultraviolet-b radiation in montane ponds

    Science.gov (United States)

    Adams, M.J.; Schindler, D.E.; Bury, B.R.

    2001-01-01

    Ambient ultraviolet-b (UV-B) radiation (280-320 nm) has increased at north-temperate latitudes in the last two decades. UV-B can be detrimental to amphibians, and amphibians have shown declines in some areas during this same period. We documented the distribution of amphibians and salmonids in 42 remote, subalpine and alpine ponds in Olympic National Park, Washington, United States. We inferred relative exposure of amphibian habitats to UV-B by estimating the transmission of 305- and 320-nm radiation in pond water. We found breeding Ambystoma gracile, A. macrodactylum and Rana cascadae at 33%, 31%, and 45% of the study sites, respectively. Most R. cascadae bred in fishless shallow ponds with relatively low transmission of UV-B. The relationship with UV-B exposure remained marginally significant even after the presence of fish was included in the model. At 50 cm water depth, there was a 55% reduction in incident 305-nm radiation at sites where breeding populations of R. cascadae were detected compared to other sites. We did not detect associations between UV-B transmission and A. gracile or A. macrodactylum. Our field surveys do not provide evidence for decline of R. cascadae in Olympic National Park as has been documented in Northern California, but are consistent with the hypothesis that the spatial distribution of R. cascadae breeding sites is influenced by exposure to UV-B. Substrate or pond depth could also be related to the distribution of R. cascadae in Olympic National Park.

  8. Applications of geographic information systems and remote sensing techniques to conservation of amphibians in northwestern Ecuador

    Directory of Open Access Journals (Sweden)

    Mariela Palacios González

    2015-01-01

    Full Text Available The biodiversity of the Andean Chocó in western Ecuador and Colombia is threatened by anthropogenic changes in land cover. The main goal of this study was to contribute to conservation of 12 threatened species of amphibians at a cloud forest site in northwestern Ecuador, by identifying and proposing protection of critical areas. We used Geographic Information Systems (GIS and remote sensing techniques to quantify land cover changes over 35 years and outline important areas for amphibian conservation. We performed a supervised classification of an IKONOS satellite image from 2011 and two aerial photographs from 1977 and 2000. The 2011 IKONOS satellite image classification was used to delineate areas important for conservation of threatened amphibians within a 200 m buffer around rivers and streams. The overall classification accuracy of the three images was ≥80%. Forest cover was reduced by 17% during the last 34 years. However, only 50% of the study area retained the initial (1977 forest cover, as land was cleared for farming and eventually reforested. Finally, using the 2011 IKONOS satellite image, we delineated areas of potential conservation interest that would benefit the long term survival of threatened amphibian species at the Ecuadorian cloud forest site studied.

  9. Dynamic stability of communities of amphibians in short-term-flooded forest ecosystems

    Directory of Open Access Journals (Sweden)

    O. V. Zhukov

    2015-09-01

    Full Text Available The estimation of stability of amphibian populations on the basis of data of population dynamics is given. The paper shows an attempt to estimate the direction of dynamic changes of amphibian populations, and defines the rate of the system deviation from the stationary state due to possible influence of the environmental factors by using concepts such as reactivity, degree of reactivity and flexibility of the system when using their indexes. It is found that populations of amphibians are quite stable with regard to quantifying these species. Characteristic feature is the elasticity of the system. It is confirmed by the elasticity of the system species Bufo bufo (Linnaeus, 1758. TypePelobates fuscus (Laurenti, 1768 is defined as a factor of stability of the system in quantitative terms. Dependenceof dynamics of the population on its size is established using the regression equation. Dynamics of groups depends on the action of possible predictors in response to which the population of B. bufo is not changed. The ecosystem is characterized as a place of interaction between biotic factors and factors of abiotic origin, which are due to the external action. Internal factor of the ecosystem stability is the influence of some amphibian populations on the other ones. The system features sustainable and relatively stable number of B. bufo, which does not affect the level of its stability. Stationary state of the grouping is unstable due to dynamic matrix, which describes the behavior of the group in the vicinity of the first stationary state. The second steady state is stableone, and the system returns to the stationary state with the help of wave-like dynamics. On the basis of our study it is established that the number of groups of amphibians remains stable, the systems behave differently, and dynamics of their return to the stationary state is elastic or reactive one. Еcosystems within lime-ash oak forests in the Central floodplain of the Samarariver

  10. 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

  11. Spatial and temporal variation in radiation exposure of amphibians - Implications for environmental risk assessment

    International Nuclear Information System (INIS)

    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 137Cs contaminated wetland area and their body content of 137Cs 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 137Cs 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, 137Cs 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, possibly due to differences in summer

  12. Environmental levels of Zn do not protect embryos from Cu toxicity in three species of amphibians.

    Science.gov (United States)

    Weir, Scott M; Flynn, R Wesley; Scott, David E; Yu, Shuangying; Lance, Stacey L

    2016-07-01

    Contaminants often occur as mixtures in the environment, but investigations into toxicity usually employ a single chemical. Metal contaminant mixtures from anthropogenic activities such as mining and coal combustion energy are widespread, yet relatively little research has been performed on effects of these mixtures on amphibians. Considering that amphibians tend to be highly sensitive to copper (Cu) and that metal contaminants often occur as mixtures in the environment, it is important to understand the interactive effects that may result from multiple metals. Interactive effects of Cu and zinc (Zn) on amphibians have been reported as antagonistic and, conversely, synergistic. The goal of our study was to investigate the role of Zn in Cu toxicity to amphibians throughout the embryonic developmental period. We also considered maternal effects and population differences by collecting multiple egg masses from contaminated and reference areas for use in four experiments across three species. We performed acute toxicity experiments with Cu concentrations that cause toxicity (10-200 μg/L) in the absence of other contaminants combined with sublethal concentrations of Zn (100 and 1000 μg/L). Our results suggest very few effects of Zn on Cu toxicity at these concentrations of Zn. As has been previously reported, we found that maternal effects and population history had significant influence on Cu toxicity. The explanation for a lack of interaction between Cu and Zn in this experiment is unknown but may be due to the use of sublethal Zn concentrations when previous experiments have used Zn concentrations associated with acute toxicity. Understanding the inconsistency of amphibian Cu/Zn mixture toxicity studies is an important research direction in order to create generalities that can be used to understand risk of contaminant mixtures in the environment. PMID:27086071

  13. Most of the Dominant Members of Amphibian Skin Bacterial Communities Can Be Readily Cultured.

    Science.gov (United States)

    Walke, Jenifer B; Becker, Matthew H; Hughey, Myra C; Swartwout, Meredith C; Jensen, Roderick V; Belden, Lisa K

    2015-10-01

    Currently, it is estimated that only 0.001% to 15% of bacteria in any given system can be cultured by use of commonly used techniques and media, yet culturing is critically important for investigations of bacterial function. Despite this situation, few studies have attempted to link culture-dependent and culture-independent data for a single system to better understand which members of the microbial community are readily cultured. In amphibians, some cutaneous bacterial symbionts can inhibit establishment and growth of the fungal pathogen Batrachochytrium dendrobatidis, and thus there is great interest in using these symbionts as probiotics for the conservation of amphibians threatened by B. dendrobatidis. The present study examined the portion of the culture-independent bacterial community (based on Illumina amplicon sequencing of the 16S rRNA gene) that was cultured with R2A low-nutrient agar and whether the cultured bacteria represented rare or dominant members of the community in the following four amphibian species: bullfrogs (Lithobates catesbeianus), eastern newts (Notophthalmus viridescens), spring peepers (Pseudacris crucifer), and American toads (Anaxyrus americanus). To determine which percentage of the community was cultured, we clustered Illumina sequences at 97% similarity, using the culture sequences as a reference database. For each amphibian species, we cultured, on average, 0.59% to 1.12% of each individual's bacterial community. However, the average percentage of bacteria that were culturable for each amphibian species was higher, with averages ranging from 2.81% to 7.47%. Furthermore, most of the dominant operational taxonomic units (OTUs), families, and phyla were represented in our cultures. These results open up new research avenues for understanding the functional roles of these dominant bacteria in host health. PMID:26162880

  14. Inventory of Amphibians and Reptiles at Manzanar National Historic Site, California

    Science.gov (United States)

    Persons, Trevor B.; Nowak, Erika M.; Hillard, Scott

    2006-01-01

    We conducted a baseline inventory for amphibians and reptiles at Manzanar National Historic Site (MANZ), Inyo County, California, in 2002-3. Objectives for this inventory were to: 1) inventory and document the occurrence of reptile and amphibian species at MANZ, with the goal of documenting at least 90% of the species present; 2) provide one voucher specimen for each species identified; 3) provide a GIS-referenced list of sensitive species that are known to be federally- or state-listed, rare, or worthy of special consideration that occur at MANZ; 4) describe park-wide distribution of federally- or state-listed, rare, or special concern species; 5) enter all species data into the National Park Service NPSpecies database; and 6) provide all deliverables as outlined in the Mojave Network Biological Inventory Study Plan. Survey methods included time-area constrained searches, lizard line transects, general surveys, nighttime road driving, and pitfall trapping. We documented the occurrence of ten reptile species (seven lizards and three snakes), but found no amphibians. Based on our findings, as well as literature review and searches for museum specimen records, we estimate inventory completeness for Manzanar to be 50%. Although the distribution and relative abundance of common lizard species is now known well enough to begin development of a monitoring protocol for that group, additional inventory work is needed in order to establish a baseline of species occurrence of amphibians and snakes at Manzanar. Key Words: amphibians, reptiles, Manzanar National Historic Site, Inyo County, California, Owens Valley, Mojave Desert, Great Basin Desert, inventory.

  15. Germ tube mediated invasion of Batrachochytrium dendrobatidis in amphibian skin is host dependent.

    Directory of Open Access Journals (Sweden)

    Pascale Van Rooij

    Full Text Available Batrachochytrium dendrobatidis (Bd is the causative agent of chytridiomycosis, a fungal skin disease in amphibians and driver of worldwide amphibian declines.We focussed on the early stages of infection by Bd in 3 amphibian species with a differential susceptibility to chytridiomycosis. Skin explants of Alytes muletensis, Litoria caerulea and Xenopus leavis were exposed to Bd in an Ussing chamber for 3 to 5 days. Early interactions of Bd with amphibian skin were observed using light microscopy and transmission electron microscopy. To validate the observations in vitro, comparison was made with skin from experimentally infected frogs. Additional in vitro experiments were performed to elucidate the process of intracellular colonization in L. caerulea. Early interactions of Bd with amphibian skin are: attachment of zoospores to host skin, zoospore germination, germ tube development, penetration into skin cells, invasive growth in the host skin, resulting in the loss of host cell cytoplasm. Inoculation of A. muletensis and L. caerulea skin was followed within 24 h by endobiotic development, with sporangia located intracellularly in the skin. Evidence is provided of how intracellular colonization is established and how colonization by Bd proceeds to deeper skin layers. Older thalli develop rhizoid-like structures that spread to deeper skin layers, form a swelling inside the host cell to finally give rise to a new thallus. In X. laevis, interaction of Bd with skin was limited to an epibiotic state, with sporangia developing upon the skin. Only the superficial epidermis was affected. Epidermal cells seemed to be used as a nutrient source without development of intracellular thalli. The in vitro data agreed with the results obtained after experimental infection of the studied frog species. These data suggest that the colonization strategy of B. dendrobatidis is host dependent, with the extent of colonization most likely determined by inherent

  16. Patterns of Assemblage Structure Indicate a Broader Conservation Potential of Focal Amphibians for Pond Management.

    Science.gov (United States)

    Soomets, Elin; Rannap, Riinu; Lõhmus, Asko

    2016-01-01

    Small freshwater ponds host diverse and vulnerable biotic assemblages but relatively few conspicuous, specially protected taxa. In Europe, the amphibians Triturus cristatus and Pelobates fuscus are among a few species whose populations have been successfully restored using pond restoration and management activities at the landscape scale. In this study, we explored whether the ponds constructed for those two target species have wider conservation significance, particularly for other species of conservation concern. We recorded the occurrence of amphibians and selected aquatic macro-invertebrates (dragonflies; damselflies; diving beetles; water scavenger beetles) in 66 ponds specially constructed for amphibians (up to 8 years post construction) and, for comparison, in 100 man-made ponds (created by local people for cattle or garden watering, peat excavation, etc.) and 65 natural ponds in Estonia. We analysed nestedness of the species assemblages and its dependence on the environment, and described the co-occurrence patterns between the target amphibians and other aquatic species. The assemblages in all ponds were significantly nested, but the environmental determinants of nestedness and co-occurrence of particular species differed among pond types. Constructed ponds were most species-rich irrespective of the presence of the target species; however, T. cristatus was frequent in those ponds and rare elsewhere, and it showed nested patterns in every type of pond. We thus conclude that pond construction for the protected amphibians can serve broader habitat conservation aims in the short term. However, the heterogeneity and inconsistent presence of species of conservation concern observed in other types of ponds implies that long-term perspectives on pond management require more explicit consideration of different habitat and biodiversity values. We also highlight nestedness analysis as a tool that can be used for the practical task of selecting focal species for

  17. Assessing changes in amphibian population dynamics following experimental manipulations of introduced fish.

    Science.gov (United States)

    Pope, Karen L

    2008-12-01

    Sport-fish introductions are now recognized as an important cause of amphibian decline, but few researchers have quantified the demographic responses of amphibians to current options in fisheries management designed to minimize effects on sensitive amphibians. Demographic analyses with mark-recapture data allow researchers to assess the relative importance of survival, local recruitment, and migration to changes in population densities. I conducted a 4-year, replicated whole-lake experiment in the Klamath Mountains of northern California (U.S.A.) to quantify changes in population density, survival, population growth rate, and recruitment of the Cascades frog (Rana cascadae) in response to manipulations of non-native fish populations. I compared responses of the frogs in lakes where fish were removed, in lakes in their naturally fish-free state, and in lakes where fish remained that were either stocked annually or no longer being stocked. Within 3 years of fish removals from 3 lakes, frog densities increased by a factor of 13.6. The survival of young adult frogs increased from 59% to 94%, and realized population growth and recruitment rates at the fish-removal lakes were more than twice as high as the rates for fish-free reference lakes and lakes that contained fish. Population growth in the fish-removal lakes was likely due to better on-site recruitment of frogs to later life stages rather than increased immigration. The effects on R. cascadae of suspending stocking were ambiguous and suggested no direct benefit to amphibians. With amphibians declining worldwide, these results show that active restoration can slow or reverse the decline of species affected by fish stocking within a short time frame. PMID:18680499

  18. Assessing DNA Barcodes for Species Identification in North American Reptiles and Amphibians in Natural History Collections

    Science.gov (United States)

    Chambers, E. Anne; Hebert, Paul D. N.

    2016-01-01

    Background High rates of species discovery and loss have led to the urgent need for more rapid assessment of species diversity in the herpetofauna. DNA barcoding allows for the preliminary identification of species based on sequence divergence. Prior DNA barcoding work on reptiles and amphibians has revealed higher biodiversity counts than previously estimated due to cases of cryptic and undiscovered species. Past studies have provided DNA barcodes for just 14% of the North American herpetofauna, revealing the need for expanded coverage. Methodology/Principal Findings This study extends the DNA barcode reference library for North American herpetofauna, assesses the utility of this approach in aiding species delimitation, and examines the correspondence between current species boundaries and sequence clusters designated by the BIN system. Sequences were obtained from 730 specimens, representing 274 species (43%) from the North American herpetofauna. Mean intraspecific divergences were 1% and 3%, while average congeneric sequence divergences were 16% and 14% in amphibians and reptiles, respectively. BIN assignments corresponded with current species boundaries in 79% of amphibians, 100% of turtles, and 60% of squamates. Deep divergences (>2%) were noted in 35% of squamate and 16% of amphibian species, and low divergences (<2%) occurred in 12% of reptiles and 23% of amphibians, patterns reflected in BIN assignments. Sequence recovery declined with specimen age, and variation in recovery success was noted among collections. Within collections, barcodes effectively flagged seven mislabeled tissues, and barcode fragments were recovered from five formalin-fixed specimens. Conclusions/Significance This study demonstrates that DNA barcodes can effectively flag errors in museum collections, while BIN splits and merges reveal taxa belonging to deeply diverged or hybridizing lineages. This study is the first effort to compile a reference library of DNA barcodes for herpetofauna

  19. Rock Phosphate Solubilization Mechanisms of One Fungus and One Bacterium

    Institute of Scientific and Technical Information of China (English)

    LIN Qi-mei; ZHAO Xiao-rong; ZHAO Zi-juan; LI Bao-guo

    2002-01-01

    Many microorganisms can dissolve the insoluble phosphates like apatite. However, the mechanisms are still not clear. This study was an attempt to investigate the mechanisms of rock phosphate solubilization by an Aspergillus 2TCiF2 and an Arthrobacter1TCRi7. The results indicated that the fungus produced a large amount of organic acids, mainly oxalic acid. The total quantity of the organic acids produced by the fungus was 550 times higher than that by the bacterium. Different organic acids had completely different capacities to solubilize the rock. Oxalic acid and citric acid had stronger capacity to dissolve the rock than malic acid, tartaric acid, lactic acid, acetic acid, malonic acid and succinic acid. The fungus solubilized the rock through excreting both proton and organic acids. The rock solubilization of the bacterium depended on only proton.

  20. Species Diversity and Distribution of Amphibians and Reptiles in Nature Park "Sinite Kamani" in Stara Planina Mt. (Bulgaria

    Directory of Open Access Journals (Sweden)

    Stanimira R. Deleva

    2014-12-01

    Full Text Available The current study presents briefly the species composition and distribution of the amphibians and reptiles in the Nature Park "Sinite Kamani" in Stara Planina Mnt. Bulgaria, based on a 2×2 km UTM grid. Between 2012 and 2014, we identified total 20 species (7 amphibians and 13 reptiles. We documented three new amphibian species for the region (Hyla arborea, Rana dalmatina and Rana graeca, which is discovered for the area for the first time and three species of reptiles (Testudo hermanni, Ablepharus kitaibelii and Lacerta trilienata. The contemporary conservation status for each species is presented and conservation threats and problems, specific for the park are discussed.

  1. Isolation and identification of iron ore-solubilising fungus

    Directory of Open Access Journals (Sweden)

    Damase Khasa

    2010-09-01

    Full Text Available Potential mineral-solubilising fungi were successfully isolated from the surfaces of iron ore minerals. Four isolates were obtained and identified by molecular and phylogenetic methods as close relatives of three different genera, namely Penicillium (for isolate FO, Alternaria (for isolates SFC2 and KFC1 and Epicoccum (for isolate SFC2B. The use of tricalcium phosphate (Ca3(PO42in phosphate-solubilising experiments confirmed isolate FO as the only phosphate solubiliser among the isolated fungi. The bioleaching capabilities of both the fungus and its spent liquid medium were tested and compared using two types of iron ore materials, conglomerate and shale, from the Sishen Iron Ore Mine as sources of potassium (K and phosphorus (P. The spent liquid medium removed more K (a maximum of 32.94% removal, from conglomerate, than the fungus (a maximum of 21.36% removal, from shale. However, the fungus removed more P (a maximum of 58.33% removal, from conglomerate than the spent liquid medium (a maximum of 29.25% removal, from conglomerate. The results also indicated a potential relationship between the removal of K or P and the production of organic acids by the fungus. A high production of gluconic acid could be related to the ability of the fungus to reduce K and P. Acetic, citric and maleic acids were also produced by the fungus, but in lower quantities. In addition, particle size and iron ore type were also shown to have significant effects on the removal of potassium and phosphorus from the iron ore minerals. We therefore conclude that the spent liquid medium from the fungal isolate FO can potentially be used for biobeneficiation of iron ore minerals.

  2. A new cytosporone derivative from the endophytic fungus Cytospora sp.

    Science.gov (United States)

    Takano, Tomoya; Koseki, Takuya; Koyama, Hiromasa; Shiono, Yoshihito

    2014-07-01

    Japanese oak wilt (JOW) is a tree disease caused by the fungus Raffaelea quercivora, which is vectored by the ambrosia beetle, Platypus quercivorus. In a screening study of the inhibitory active compounds from fungi, a new cytosporone analogue, compound 1, was isolated from the endophytic fungus Cytospora sp. TT-10 isolated from Japanese oak, together with the known compounds, integracin A (2), cytosporones N (3) and A (4). Their structures were determined by extensive 1D- and 2D-NMR spectroscopic and mass spectral analyses. Compound 1 was identified as 4,5-dihydroxy-3-heptylphthalide and named cytosporone E. Compounds 2 and 3 showed antimicrobial activity against Raffaelea quercivora. PMID:25230507

  3. Source of fungus contamination of hydrophilic soft contact lenses.

    Science.gov (United States)

    Gasset, A R; Mattingly, T P; Hood, I

    1979-09-01

    Fungus infiltration within hydrophilic lenses has been a rare finding. This case report confirms previous findings that fungal contamination of hydrophilic contact lens is possible. The present report, to our knowledge, is the first demonstration of the association of fungus from contaminated cosmetics with hydrophilic contact lenses. It is important to be aware of the possibility of fungal invasion of hydrophilic lenses, as well as to be able to differentiate this from the more common harmless spot formation. On the basis of this study, good lid hygiene, strict adherence to the sterilization procedure, and discontinuance of any soft hydrophilic contact lenses with spot formation seems appropriate. PMID:556154

  4. Transformation of Metalaxyl by the Fungus Syncephalastrum racemosum†

    OpenAIRE

    Zheng, Zhong; Liu, Shu-Yen; Freyer, Alan J.; Bollag, Jean-Marc

    1989-01-01

    The fungus Syncephalastrum racemosum (Cohn) Schroeter was found to transform the fungicide metalaxyl [N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-alanine methyl ester] in pure culture. After 21 days of incubation in a basal medium amended with 5 μg of metalaxyl per ml, more than 80% of the compound was transformed by the fungus. The transformation rates decreased as the concentrations of metalaxyl increased from 5 to 100 μg/ml. No transformation was observed when the concentration of metalaxyl w...

  5. Roles of Peroxisomes in the Rice Blast Fungus.

    Science.gov (United States)

    Chen, Xiao-Lin; Wang, Zhao; Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity. PMID:27610388

  6. Experimental study of Aspergillus flavus fungus from uranium mines

    International Nuclear Information System (INIS)

    Cultivation is discussed of fungus strain Aspergillus flavus obtained from materials from uranium mines. It was found that an addition of 0.6 g of uranium in form of uranyl acetate or of 0.6 g of thorium in form on thorium nitrate in 1000 ml of the standard medium had stimulating effects on the growth and sporulation of Aspergillus flavus. Irradiating the cultivated fungus through a polyethylene foil did not show a stimulating effect. It is stated that uranium and its daughters must be directly present in the culture medium for their stimulating effect on growth and sporulation to manifest itself. (H.S.)

  7. New aquatic sites of the fungus Sommerstorffia spinosa

    Directory of Open Access Journals (Sweden)

    Bazyli Czeczuga

    2014-08-01

    Full Text Available When studying zoosporic fungi in the waters of northeastern Poland tbe authors found new sites of a rare fungus - Sommerstorffia spinosa Arnaudow. Its growth was observed in water samples collected from limnologically different reservoirs, from the spring Jaroszówka, the oligotrophic type (Lake Białe, through mesotrophic (Lake Wigry to the polytrophic type (pond Fosa with high content of hydrogen sulphide under ice cover. This fungus was also found in the river Biała, which flowing through Białystok gets polluted by municipal wastes. Moreover, the successive stages of S. spinosa development in the aquatic environment are described.

  8. Patterns of functional enzyme activity in fungus farming ambrosia beetles

    Directory of Open Access Journals (Sweden)

    De Fine Licht Henrik H

    2012-06-01

    Full Text Available Abstract Introduction In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae, wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily

  9. Current Situations of Edible Fungus Production in Lianyungang City and Development Countermeasures

    Institute of Scientific and Technical Information of China (English)

    LI Guan-xi; GE Xiong-can; WEI Liang-zhi

    2012-01-01

    On the basis of characteristics of edible fungus production in Lianyungang City, we analyzed its advantages and disadvantages and put forward suggestions and countermeasures for development of edible fungus industry, mainly including strengthening guidance and leadership of government, introducing professional personnel, and developing the edible fungus industry through science and technology.

  10. Towards an integrated understanding of the consequences of fungus domestication on the fungus-growing termite gut microbiota

    DEFF Research Database (Denmark)

    Thomas-Poulsen, Michael

    2015-01-01

    Approximately 30 million years ago (MYA), the subfamily of higher termites Macrotermitinae domesticated a fungus, Termitomyces, as the main plant decomposer and food source for the termite host. The origin of fungiculture shifted the composition of the termite gut microbiota, and some of the...... powerful, particularly if executed in comparative analyses across the well-established congruent termite-fungus phylogenies. This will allow for testing if gut communities have evolved in parallel with their hosts, with implications for our general understanding of the evolution of gut symbiont communities...

  11. COMPARING THE EFFECTS OF RETINOIC ACID ON AMPHIBIAN LIMB DEVELOPMENT AND LETHALITY: CHRONIC EXPOSURE RESULTS IN LETHALITY NOT LIMB MALFORMATIONS

    Science.gov (United States)

    Recently, high frequencies of malformations have been reported in amphibians across the United States. It has been suggested that the malformations may be the result of xenobiotic disruption of retinoid signaling pathways during embryogenesis and tadpole development. Therefore, a...

  12. Direct evidence for the role of pesticides in amphibian population declines in the Sierra Nevada Mountains, California, USA

    Science.gov (United States)

    For 20 years, conservationists have agreed that amphibian populations around the world are declining. Proposed causes of these declines include habitat loss, environmental contaminants, disease, introduced predators, global climate change, and others. Substantial but indirect evidence through labo...

  13. 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

  14. High amphibian diversity related to unexpected environmental values in a biogeographic transitional area in north-western Mexico

    OpenAIRE

    Serrano, J. M.; Berlanga-Robles, C.A.; Ruiz-Luna, A.

    2014-01-01

    Amphibian diversity and distribution patterns in Sinaloa state (north-western Mexico) were assessed from the Global Amphibian Assessment database (GAA-2010). A geographic information system (GIS) was used to evaluate diversity based on distribution maps of 41 species, associated with environmental data. The highest α and γ-diversities were identified in the south-eastern portion of the state, in mountain zones with a warm sub-humid climate, whereas the greatest β-diversity (multiplicative for...

  15. Herpetofaunal assemblage with special emphasis on community structure and spatiality in amphibians of Cauvery delta region, Tamil Nadu

    OpenAIRE

    Anukul Nath; Sanjoy Sutradhar; A. Kalai Mani; Vishnu Vijyan; Krishna Kumar; B. Laxmi Narayana; B. Naresh; G. Baburao; Sneha Dharwadkar; Gokul Krishnan; B Vinoth; R. Maniraj; D. Mahendar Reddy; D. Adi mallaiah; Kummari Swamy

    2012-01-01

    We studied the amphibian community structure, spatial overlap and herpetofaunal assemblage at Mannampandal, Tamil Nadu during October, 2010 to January, 2011. The survey methods involved careful visual estimation of amphibians in all the possible microhabitats present in the study area. Five different microhabitat categories were selected, viz., leaf litters, temporary water pools, tree holes, shrubs & grasses (ground vegetation), pathways, open floor & outer edges of buildings. We identified ...

  16. Phospholipase C and Diacylglycerol Mediate Olfactory Responses to Amino Acids in the Main Olfactory Epithelium of an Amphibian

    OpenAIRE

    Alfredo Sansone; Thomas Hassenklöver; Syed, Adnan S; Sigrun I. Korsching; Ivan Manzini

    2014-01-01

    The semi-aquatic lifestyle of amphibians represents a unique opportunity to study the molecular driving forces involved in the transition of aquatic to terrestrial olfaction in vertebrates. Most amphibians have anatomically segregated main and vomeronasal olfactory systems, but at the cellular and molecular level the segregation differs from that found in mammals. We have recently shown that amino acid responses in the main olfactory epithelium (MOE) of larval Xenopus laevis segregate into a ...

  17. A survey of amphibians and reptiles in Chu Mom Ray National Park, Vietnam, with implications for herpetofaunal conservation

    Directory of Open Access Journals (Sweden)

    Daniel Jestrzemski

    2013-12-01

    Full Text Available A herpetological survey was conducted in spring 2012 in the eastern part of Chu Mom Ray National Park, Kon Tum Province, southern Vietnam, to create a first inventory list of amphibians and reptiles and record threats to the local herpetocommunity. We also evaluated the efficiency of two faunistic inventory methods, drift fences and transect visual encounter surveys, in detecting reptiles and amphibians under the given circumstances. Five drift fence arrays with pitfalls and double-ended funnel traps were set up in lowland evergreen forest at elevations from 777 to 846 m a.s.l. and monitored over 40 nights. Additionally, 22 night excursions were conducted along an adjacent forest stream transect. A total of 62 species of amphibians and reptiles were recorded, comprising 24 anurans, one caecilian, 20 lizards, 16 snakes and one freshwater turtle. Because all specimens were released after capture in the field, proper identification and taxonomic revision are required for at least ten recorded amphibian and six reptile species. Four species are listed in the Vietnam Red Data Book (2007 and two species are listed in the Governmental Decree No32/2006/ND-CP (2006. In terms of distribution patterns, old-growth forest habitat harbored the highest number of recorded reptiles and amphibians (41 species, followed by open land (18 species and secondary forest (14 species. Most species were captured opportunistically (34, followed by the drift fences (29 and transect night surveys (18. Opportunistic encounters provided for most reptiles (22, while most amphibians were recorded at the drift fence arrays (15. Poaching of wildlife proved to be the major threat to the local herpetofauna, in particular large reptiles. In the study area, reptiles and amphibians are also at risk from habitat loss and degradation. Recommendations for reptile and amphibian conservation are provided.

  18. Multi-species occupancy modeling of natural and anthropogenic habitats by mediterranean amphibians: grim prospects for conservation in irrigated farmland

    OpenAIRE

    Ferreira, Mário Rui Mota

    2012-01-01

    This study approaches the destruction of temporary ponds in an intensified agricultural landscape and the alternative breeding habitats for the amphibian community. We used several surveys to model the ponds survival since 1991 until 2009. Ponds inside the irrigation perimeter have a significant lower survival probability then those outside. Ponds, agricultural reservoirs, streams, irrigation channels and ditches were sampled for amphibian larvae in four different periods of a breeding season...

  19. Forest Fragments Surrounded by Sugar Cane Are More Inhospitable to Terrestrial Amphibian Abundance Than Fragments Surrounded by Pasture

    OpenAIRE

    Paula Eveline Ribeiro D’Anunciação; Marcela Fernandes Vilela Silva; Lucas Ferrante; Diego Santana Assis; Thamires Casagrande; Andréa Zalmora Garcia Coelho; Bárbara Christina Silva Amâncio; Túlio Ribeiral Pereira; Vinícius Xavier da Silva

    2013-01-01

    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 di...

  20. Fun Microbiology: How To Measure Growth of a Fungus.

    Science.gov (United States)

    Mitchell, James K.; And Others

    1997-01-01

    Describes an experiment to demonstrate a simple method for measuring fungus growth by monitoring the effect of temperature on the growth of Trichoderma viride. Among the advantages that this experimental model provides is introducing students to the importance of using the computer as a scientific tool for analyzing and presenting data. (AIM)