WorldWideScience

Sample records for amazonian amphibian diversity

  1. North American amphibians: distribution and diversity

    Science.gov (United States)

    : Green, David M.; Weir, Linda A.; Casper, Gary S.; Lannoo, Michael

    2014-01-01

    Some 300 species of amphibians inhabit North America. The past two decades have seen an enormous growth in interest about amphibians and an increased intensity of scientific research into their fascinating biology and continent-wide distribution. This atlas presents the spectacular diversity of North American amphibians in a geographic context. It covers all formally recognized amphibian species found in the United States and Canada, many of which are endangered or threatened with extinction. Illustrated with maps and photos, the species accounts provide current information about distribution, habitat, and conservation. Researchers, professional herpetologists, and anyone intrigued by amphibians will value North American Amphibians as a guide and reference.

  2. Global patterns of amphibian phylogenetic diversity

    DEFF Research Database (Denmark)

    Fritz, Susanne; Rahbek, Carsten

    2012-01-01

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

  3. Carbon dynamics and ecosystem diversity of Amazonian peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laehteenoja, O.

    2011-07-01

    The overall aim was to initiate peatland research in Amazonia, which has been referred to as 'one of the large white spots on the global peatland map'. Specifically, the study was to clarify how common peat accumulation is on Amazonian floodplains, and how extensive and thick peat deposits can be encountered. Secondly, the intention was to study how rapidly Amazonian peatlands sequester carbon, and how much carbon they store and thirdly, to gain some understanding of the diversity of peatland ecosystem types and of the processes forming these ecosystems

  4. Phylogenetic diversity of Amazonian tree communities

    OpenAIRE

    Honorio Coronado, Eurídice N.; Dexter, Kyle G.; Pennington, R. Toby; Chave, Jérôme; Lewis, Simon L.; Alexiades, Miguel N.; Alvarez, Esteban; Alves de Oliveira, Atila; Amaral, Iêda L.; Araujo-Murakami, Alejandro; Arets, Eric J. M. M.; Aymard, Gerardo A.; Baraloto, Christopher; Bonal, Damien; Brienen, Roel

    2015-01-01

    Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses...

  5. Amphibian and reptile diversity of the Lahontan Valley

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is about a survey that was done to assess the amphibian and reptile diversity of the Lahontan Valley in Nevada. The work contained in this summary can...

  6. Climate change and amphibian diversity patterns in Mexico

    DEFF Research Database (Denmark)

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

    2012-01-01

    The aim of this article is to characterize at fine scale alpha and beta diversity patterns for Mexican amphibians and analyze how these patterns might change under a moderate climate-change scenario, highlighting the overall consequences for amphibian diversity at the country level. We used a geo...... 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...... country boundaries) were particularly intense during the period 2020–2050. The results implied that heterogeneous zones associated with mountain ranges will remain particularly important for amphibian diversity and thus constitute areas for continued conservation prioritization in the face of climate...

  7. Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru. Part 1: Primates

    OpenAIRE

    Farid Pazhoohi

    2011-01-01

    Review of Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru. Part 1: Primates. Robert S. Voss and David W. Fleck. 2011. Bulletin of the American Museum of Natural History, Number 351. Pp.81, 3 figures, 25 tables. Free at AMNH Digital Library ISSN 0003‐0090.

  8. Amphibians.

    Science.gov (United States)

    Naturescope, 1987

    1987-01-01

    Describes some of the characteristics of amphibians. Contains teaching activities ranging from a "frog sing-along" to lessons on amphibian adaptations, and night hikes to identify frog calls. Includes reproducible handouts to be used with the activities, and a quiz. (TW)

  9. 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

  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. Diversity and genetic structure analysis of three Amazonian Amerindian populations from Colombia

    Directory of Open Access Journals (Sweden)

    Yamid Braga

    2012-06-01

    Full Text Available 14.00 Normal 0 21 false false false ES-CO X-NONE X-NONE Introduction: In the departments of the Vaupés and Guaviare, in southeastern Colombia, in a transitional area between Amazonia and the eastern plains, inhabit indigenous groups belonging to the Tukanoan (East and Guahiban linguistic families. Although some studies have dealt with the culture and the cosmology description of these groups, little research has been done on the biological diversity and genetic relationships of such groups. Objective: To estimate the diversity, the structure, and the genetic relationships of one Guahiban and two Tukanoan groups of the Colombian Amazonian region. Methods: Samples were collected (n = 106 from unrelated individuals belonging to the Vaupés native indigenous commu­nities. The DNA was extracted and nine autosomal microsatellites were typed. Several measures of diversity, FST, pairwise FST, and population differentiation between groups were calculated. Finally, it was estimated the genetic distances of the groups studied in relation with other Amazonian, Andean and Central American indigenous people. Results: 1. The genetic diversity found stands within the range of other Amazonian populations, whereas compared to the mestizo and afro-descendant Colombian populations, such diversity showed to be lower. 2. The structure and population differentiation tests showed two clusters; one consisting of the Vaupés Tukanoan and Guaviare Tukanoan groups, and a second one formed by the Guayabero. 3. Tukanoan groups are found to be closer related to the Brazilian Amazonian po­pulations than to the Guayabero. Conclusion: The results of this study suggest that the Guayabero group from Guaviare, are genetically differentiated from those Tukanoan groups of the Vaupés and Guaviare

  12. Diversity and genetic structure analysis of three Amazonian Amerindian populations from Colombia

    Directory of Open Access Journals (Sweden)

    Yamid Braga

    2012-06-01

    Full Text Available Introduction: In the departments of the Vaupés and Guaviare, in southeastern Colombia, in a transitional area between Amazonia and the eastern plains, inhabit indigenous groups belonging to the Tukanoan (East and Guahiban linguistic families. Although some studies have dealt with the culture and the cosmology description of these groups, little research has been done on the biological diversity and genetic relationships of such groups.Objective: To estimate the diversity, the structure, and the genetic relationships of one Guahiban and two Tukanoan groups of the Colombian Amazonian region.Methods: Samples were collected (n = 106 from unrelated individuals belonging to the Vaupés native indigenous communities. The DNA was extracted and nine autosomal microsatellites were typed. Several measures of diversity, FST, pairwise FST, and population differentiation between groups were calculated. Finally, it was estimated the genetic distances of the groups studied in relation with other Amazonian, Andean and Central American indigenous people.Results: 1. The genetic diversity found stands within the range of other Amazonian populations, whereas compared to the mestizo and afro-descendant Colombian populations, such diversity showed to be lower. 2. The structure and population differentiation tests showed two clusters; one consisting of the Vaupés Tukanoan and Guaviare Tukanoan groups, and a second one formed by the Guayabero. 3. Tukanoan groups are found to be closer related to the Brazilian Amazonian populations than to the Guayabero.Conclusion: The results of this study suggest that the Guayabero group from Guaviare, are genetically differentiated from those Tukanoan groups of the Vaupés and Guaviare.

  13. 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…

  14. 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

  15. 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.

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

    Science.gov (United States)

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

    2010-08-01

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

  17. 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...

  18. 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.

  19. 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.

  20. 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

  1. Global Amphibian Declines, Loss of Genetic Diversity and Fitness: A Review

    Directory of Open Access Journals (Sweden)

    John O’Brien

    2010-01-01

    Full Text Available It is well established that a decrease in genetic variation can lead to reduced fitness and lack of adaptability to a changing environment. Amphibians are declining on a global scale, and we present a four-point argument as to why this taxonomic group seems especially prone to such genetic processes. We elaborate on the extent of recent fragmentation of amphibian gene pools and we propose the term dissociated populations to describe the residual population structure. To put their well-documented loss of genetic diversity into context, we provide an overview of 34 studies (covering 17 amphibian species that address a link between genetic variation and >20 different fitness traits in amphibians. Although not all results are unequivocal, clear genetic-fitness-correlations (GFCs are documented in the majority of the published investigations. In light of the threats faced by amphibians, it is of particular concern that the negative effects of various pollutants, pathogens and increased UV-B radiation are magnified in individuals with little genetic variability. Indeed, ongoing loss of genetic variation might be an important underlying factor in global amphibian declines.

  2. 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...

  3. The Diversity of Bitter Manioc (Manihot Esculenta Crantz Cultivation in a Whitewater Amazonian Landscape

    Directory of Open Access Journals (Sweden)

    James A. Fraser

    2010-04-01

    Full Text Available While bitter manioc has been one of the most important staple crops in the central Amazon for thousands of years, there have been few studies of its cultivation in the fertile whitewater landscapes of this region. Anthropological research on bitter manioc cultivation in the Amazon has focused almost exclusively on long-fallow shifting cultivation in marginal upland areas of low soil fertility. This has contributed to the persistence of the oversimplified notion that because bitter manioc is well adapted to infertile upland soils; it cannot yield well in alluvial and/or fertile soils. I hypothesized that bitter manioc cultivation would be well adapted to the fertile soils of the whitewater landscapes of the central Amazon because of the centrality of this crop to subsistence in this region. In this article, I examine one such whitewater landscape, the middle Madeira River, Amazonas, Brazil, where smallholders cultivate bitter manioc on fertile Amazonian Dark Earths (ADE and floodplain soils, and on infertile Oxisols and Ultisols. In this region, cultivation on fertile soils tends to be short-cycled, characterised by short fallowing (0–6 years and shorter cropping periods (5–12 months with a predominance of low starch fast maturing “weak” landraces. By contrast, cultivation on infertile soils is normally long-cycled, characterised by longer fallows (>10 years and longer cropping periods (1–3 years with a predominance of high starch slow maturing “strong” landraces. This diversity in bitter manioc cultivation systems (landraces, fallow periods, soils demonstrates that Amazonian farmers have adapted bitter manioc cultivation to the specific characteristics of the landscapes that they inhabit. I conclude that contrary to earlier claims, there are no ecological limitations on growing bitter manioc in fertile soils, and therefore the cultivation of this crop in floodplain and ADE soils would have been possible in the pre-Columbian period.

  4. A Molecular Survey of the Diversity of Microbial Communities in Different Amazonian Agricultural Model Systems

    Directory of Open Access Journals (Sweden)

    Acácio A. Navarrete

    2010-05-01

    Full Text Available The processes of land conversion and agricultural intensification are a significant cause of biodiversity loss, with consequent negative effects both on the environment and the sustainability of food production.The anthrosols associated with pre-Colombian settlements in the Amazonian region are examples of how anthropogenic activities may sustain the native populations against harsh tropical environments for human establishment, even without a previous intentionality of anthropic soil formation. In a case study (Model I—“Slash-and-Burn” the community structures detected by automated ribosomal intergenic spacer analysis (ARISA revealed that soil archaeal, bacterial and fungal communities are heterogeneous and each capable of responding differently to environmental characteristics. ARISA data evidenced considerable difference in structure existing between microbial communities in forest and agricultural soils. In a second study (Model II—“Anthropogenic Soil”, the bacterial community structures revealed by terminal restriction fragment length polymorphism (T-RFLP differed among an Amazonian Dark Earth (ADE, black carbon (BC and its adjacent non-anthropogenic oxisoil. The bacterial 16S rRNA gene (OTU richness estimated by pyrosequencing was higher in ADE than BC. The most abundant bacterial phyla in ADE soils and BC were Proteobacteria—24% ADE, 15% BC; Acidobacteria—10% ADE, 21% BC; Actinobacteria—7% ADE, 12% BC; Verrucomicrobia, 8% ADE; 9% BC; Firmicutes—3% ADE, 8% BC. Overall, unclassified bacteria corresponded to 36% ADE, and 26% BC. Regardless of current land uses, our data suggest that soil microbial community structures may be strongly influenced by the historical soil management and that anthrosols in Amazonia, of anthropogenic origins, in addition to their capacity of enhancing crop yields, may also improve microbial diversity, with the support of the black carbon, which may sustain a particular and unique habitat for the

  5. Intermediate pond sizes contain the highest density, richness, and diversity of pond-breeding amphibians.

    Directory of Open Access Journals (Sweden)

    Raymond D Semlitsch

    Full Text Available We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes.

  6. Intermediate pond sizes contain the highest density, richness, and diversity of pond-breeding amphibians.

    Science.gov (United States)

    Semlitsch, Raymond D; Peterman, William E; Anderson, Thomas L; Drake, Dana L; Ousterhout, Brittany H

    2015-01-01

    We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes.

  7. Intermediate pond sizes contain the highest density, richness, and diversity of pond-breeding amphibians.

    Science.gov (United States)

    Semlitsch, Raymond D; Peterman, William E; Anderson, Thomas L; Drake, Dana L; Ousterhout, Brittany H

    2015-01-01

    We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes. PMID:25906355

  8. Amphibian Diversity and Threatened Species in a Severely Transformed Neotropical Region in Mexico

    Science.gov (United States)

    Meza-Parral, Yocoyani; Pineda, Eduardo

    2015-01-01

    Many regions around the world concentrate a large number of highly endangered species that have very restricted distributions. The mountainous region of central Veracruz, Mexico, is considered a priority area for amphibian conservation because of its high level of endemism and the number of threatened species. The original tropical montane cloud forest in the region has been dramatically reduced and fragmented and is now mainly confined to ravines and hillsides. We evaluated the current situation of amphibian diversity in the cloud forest fragments of this region by analyzing species richness and abundance, comparing assemblage structure and species composition, examining the distribution and abundance of threatened species, and identifying the local and landscape variables associated with the observed amphibian diversity. From June to October 2012 we sampled ten forest fragments, investing 944 person-hours of sampling effort. A total of 895 amphibians belonging to 16 species were recorded. Notable differences in species richness, abundance, and assemblage structure between forest fragments were observed. Species composition between pairs of fragments differed by an average of 53%, with the majority (58%) resulting from species replacement and the rest (42%) explained by differences in species richness. Half of the species detected are under threat of extinction according to the International Union for Conservation of Nature, and although their distribution and abundance varied markedly, there were also ubiquitous and abundant species, along with rare species of restricted distribution. The evident heterogeneity of the ten study sites indicates that to conserve amphibians in a mountainous region such as this one it is necessary to protect groups of fragments which represent the variability of the system. Both individually and together cloud forest fragments are very important to conservation because each remnant is inhabited by several threatened species, some of

  9. Geomorphology Drives Amphibian Beta Diversity in Atlantic Forest Lowlands of Southeastern Brazil.

    Science.gov (United States)

    Luiz, Amom Mendes; Leão-Pires, Thiago Augusto; Sawaya, Ricardo J

    2016-01-01

    Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorphological factors are more important in structuring anuran beta diversity than climatic and spatial factors. We obtained species composition via field survey (N = 766 individuals), museum specimens (N = 9,730) and literature records (N = 4,763). Sampling area was divided in four spatially explicit geomorphological units, representing historical predictors. Climatic descriptors were represented by the first two axis of a Principal Component Analysis. Spatial predictors in different spatial scales were described by Moran Eigenvector Maps. Redundancy Analysis was implemented to partition the explained variation of species composition by geomorphological, climatic and spatial predictors. Moreover, spatial autocorrelation analyses were used to test neutral theory predictions. Beta diversity was spatially structured in broader scales. Shared fraction between climatic and geomorphological variables was an important predictor of species composition (13%), as well as broad scale spatial predictors (13%). However, geomorphological variables alone were the most important predictor of beta diversity (42%). Historical factors related to geomorphology must have played a crucial role in structuring amphibian beta diversity. The complex relationships between geomorphological history and climatic gradients generated by the Serra do Mar Precambrian basements were also important. We highlight the importance of combining spatially explicit historical and contemporary predictors for understanding

  10. Historical effects on beta diversity and community assembly in Amazonian trees

    Science.gov (United States)

    Dexter, Kyle G.; Terborgh, John W.; Cunningham, Clifford W.

    2012-01-01

    We present a unique perspective on the role of historical processes in community assembly by synthesizing analyses of species turnover among communities with environmental data and independent, population genetic-derived estimates of among-community dispersal. We sampled floodplain and terra firme communities of the diverse tree genus Inga (Fabaceae) across a 250-km transect in Amazonian Peru and found patterns of distance-decay in compositional similarity in both habitat types. However, conventional analyses of distance-decay masked a zone of increased species turnover present in the middle of the transect. We estimated past seed dispersal among the same communities by examining geographic plastid DNA variation for eight widespread Inga species and uncovered a population genetic break in the majority of species that is geographically coincident with the zone of increased species turnover. Analyses of these and 12 additional Inga species shared between two communities located on opposite sides of the zone showed that the populations experienced divergence 42,000–612,000 y ago. Our results suggest that the observed distance decay is the result not of environmental gradients or dispersal limitation coupled with ecological drift—as conventionally interpreted under neutral ecological theory—but rather of secondary contact between historically separated communities. Thus, even at this small spatial scale, historical processes seem to significantly impact species’ distributions and community assembly. Other documented zones of increased species turnover found in the western Amazon basin or elsewhere may be related to similar historical processes. PMID:22547831

  11. Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management.

    Directory of Open Access Journals (Sweden)

    Jens C Hegg

    Full Text Available Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world's largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region's largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species' migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii, Piramutaba (Brachyplatystoma vaillantii, and Piraíba (Brachyplatystoma filamentosum. We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures ((87Sr/(86Sr recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted (87Sr/(86Sr isotope values using a regression-based approach that related

  12. Intermediate Pond Sizes Contain the Highest Density, Richness, and Diversity of Pond-Breeding Amphibians

    OpenAIRE

    Semlitsch, Raymond D.; William E Peterman; Anderson, Thomas L.; Drake, Dana L.; Brittany H Ousterhout

    2015-01-01

    We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a...

  13. Amphibian diversity and endemism in the swamp forests of Agusan Marsh, Agusan del Sur, Philippines

    Directory of Open Access Journals (Sweden)

    Merlita L. Almeria

    2013-04-01

    Full Text Available Agusan Marsh, an ecologically significant wetland in the Philippines, consists of an extensivefloodplain heavily dissected by numerous rivers and streams making it a very important source offreshwater, storing more than 15% of the nation’s freshwater resource in the form of swamp forests.Since amphibians are very good indicators of climate change and ecosystem health, species diversity andendemism were assessed in sago swamp, terminalia, mixed swamp, and peat swamp forests in AgusanMarsh using a combination of cruising, pitfall trap and quadrat methods. Seventeen species with 41%endemism were recorded. Of the seven endemic species, five are Mindanao endemic. The twoundescribed species of Oreophryne and one Philautus could be new species and were observed in theterminalia, sago, and mixed swamp forests but not in the peat swamp forest. The peat swamp forestwhere the invasive Rhinella marina was abundant, had the least species richness owing to habitatdisturbance brought about by human encroachment. The highest species richness and abundance wereobserved in the terminalia forest primarily due to the presence of suitable microhabitats. Four vulnerablespecies were recorded in the marsh. Most of the vulnerable and endemic species were documented in theterminalia and mixed swamp forests. High diversity and more or less even distribution were observed inall sites. Three amphibian species are considered socio-economically important and are hunted for foodand bait for fish. The presence of endemic and vulnerable species indicates that Agusan Marsh is a keyconservation site. Logging and widespread mining, discharging tons of mine tailings into the rivers whichfind their way into the swamp forests are just some of the threats to the amphibians in the marsh.Conservation action is necessary to protect the endemic and vulnerable species in the swamp forests andthe Agusan marsh in general.

  14. Linking environmental drivers with amphibian species diversity in ponds from subtropical grasslands.

    Science.gov (United States)

    Gonçalves, Darlene S; Crivellari, Lucas B; Conte, Carlos Eduardo

    2015-09-01

    Amphibian distribution patterns are known to be influenced by habitat diversity at breeding sites. Thus, breeding sites variability and how such variability influences anuran diversity is important. Here, we examine which characteristics at breeding sites are most influential on anuran diversity in grasslands associated with Araucaria forest, southern Brazil, especially in places at risk due to anthropic activities. We evaluate the associations between habitat heterogeneity and anuran species diversity in nine body of water from September 2008 to March 2010, in 12 field campaigns in which 16 species of anurans were found. Of the seven habitat descriptors we examined, water depth, pond surface area and distance to the nearest forest fragment explained 81% of total species diversity. Water depth, margin vegetation type, surface area and distance to the next body of water explained between 31-74% of the variance in abundance of nine of the 16 species. Thus, maintenance of body of water, of the vegetation along the water edge and natural forest fragments in the grasslands, along with fire control (used to renovation of pasture), are fundamentally important for the maintenance of anuran species diversity through the conservation of their breeding sites. PMID:26421457

  15. Diversity and aspects of the ecology of social wasps (Vespidae, Polistinae in Central Amazonian "terra firme" forest

    Directory of Open Access Journals (Sweden)

    Alexandre Somavilla

    2014-12-01

    Full Text Available Diversity and aspects of the ecology of social wasps (Vespidae, Polistinae in Central Amazonian "terra firme" forest. The knowledge of social wasp richness and biology in the Amazonian region is considered insufficient. Although the Amazonas state is the largest in the region, until now only two brief surveys were conducted there. Considering that the systematic inventory of an area is the first step towards its conservation and wise use, this study presents faunal data on social wasp diversity in a 25 km² area of "terra firme" (upland forest at the Ducke Reserve, Manaus, Amazonas, Brazil. Wasps were collected in the understory, following a protocol of three collectors walking along 60 trails 1,000 m in extension for 16 days between August and October 2010. Methods used were active search of individuals with entomological nets and nest collecting. Fifty-eight species of social wasps, allocated in 13 genera, were recorded; 67% of the collected species belong to Polybia, Agelaia and Mischocyttarus; other genera were represented by only four species or less. The most frequent species in active searches were Agelaia fulvofasciata (DeGeer, 1773, Agelaia testacea (Fabricius, 1804 and Angiopolybia pallens (Lepeletier, 1836. Twelve species were collected in nests. Prior to this study, 65 Polistinae species were deposited at the INPA Collection. Collecting in the study grid, an area not previously sampled for wasps, resulted in an increase of 25% species, and species richness was 86. According to the results, there is evidence that the diversity of social wasps at the Ducke Reserve is even higher, making it one of the richest areas in the Brazilian Amazonia.

  16. 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

  17. Diversity and physiological characterization of D-xylose-fermenting yeasts isolated from the Brazilian Amazonian Forest.

    Directory of Open Access Journals (Sweden)

    Raquel M Cadete

    Full Text Available BACKGROUND: This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates. METHODOLOGY/PRINCIPAL FINDINGS: A total of 224 yeast strains were isolated from rotting wood samples collected in two Amazonian forest reserve sites. These samples were cultured in yeast nitrogen base (YNB-D-xylose or YNB-xylan media. Candida tropicalis, Asterotremella humicola, Candida boidinii and Debaryomyces hansenii were the most frequently isolated yeasts. Among D-xylose-fermenting yeasts, six strains of Spathaspora passalidarum, two of Scheffersomyces stipitis, and representatives of five new species were identified. The new species included Candida amazonensis of the Scheffersomyces clade and Spathaspora sp. 1, Spathaspora sp. 2, Spathaspora sp. 3, and Candida sp. 1 of the Spathaspora clade. In fermentation assays using D-xylose (50 g/L culture medium, S. passalidarum strains showed the highest ethanol yields (0.31 g/g to 0.37 g/g and productivities (0.62 g/L · h to 0.75 g/L · h. Candida amazonensis exhibited a virtually complete D-xylose consumption and the highest xylitol yields (0.55 g/g to 0.59 g/g, with concentrations up to 25.2 g/L. The new Spathaspora species produced ethanol and/or xylitol in different concentrations as the main fermentation products. In sugarcane bagasse hemicellulosic fermentation assays, S. stipitis UFMG-XMD-15.2 generated the highest ethanol yield (0.34 g/g and productivity (0.2 g/L · h, while the new species Spathaspora sp. 1 UFMG-XMD-16.2 and Spathaspora sp. 2 UFMG-XMD-23.2 were very good xylitol producers. CONCLUSIONS/SIGNIFICANCE: This study demonstrates the promise of using new D-xylose-fermenting yeast strains from the Brazilian Amazonian Forest for ethanol or xylitol production from sugarcane bagasse hemicellulosic hydrolysates.

  18. Paleodistributions and comparative molecular phylogeography of leafcutter ants (Atta spp. provide new insight into the origins of Amazonian diversity.

    Directory of Open Access Journals (Sweden)

    Scott E Solomon

    Full Text Available The evolutionary basis for high species diversity in tropical regions of the world remains unresolved. Much research has focused on the biogeography of speciation in the Amazon Basin, which harbors the greatest diversity of terrestrial life. The leading hypotheses on allopatric diversification of Amazonian taxa are the Pleistocene refugia, marine incursion, and riverine barrier hypotheses. Recent advances in the fields of phylogeography and species-distribution modeling permit a modern re-evaluation of these hypotheses. Our approach combines comparative, molecular phylogeographic analyses using mitochondrial DNA sequence data with paleodistribution modeling of species ranges at the last glacial maximum (LGM to test these hypotheses for three co-distributed species of leafcutter ants (Atta spp.. The cumulative results of all tests reject every prediction of the riverine barrier hypothesis, but are unable to reject several predictions of the Pleistocene refugia and marine incursion hypotheses. Coalescent dating analyses suggest that population structure formed recently (Pleistocene-Pliocene, but are unable to reject the possibility that Miocene events may be responsible for structuring populations in two of the three species examined. The available data therefore suggest that either marine incursions in the Miocene or climate changes during the Pleistocene--or both--have shaped the population structure of the three species examined. Our results also reconceptualize the traditional Pleistocene refugia hypothesis, and offer a novel framework for future research into the area.

  19. Global comparisons of beta diversity among mammals, birds, reptiles, and amphibians across spatial scales and taxonomic ranks

    Institute of Scientific and Technical Information of China (English)

    Hong QIAN

    2009-01-01

    Beta diversity is the change in species composition among areas in a geographic region. The proportion of species shared between two areas often decreases when the distance separating them increases, leading to an increase in beta diversity. This study compares beta diversity among four classes of terrestrial vertebrates (mammals, birds, reptiles, and amphibians) at both regional (biogeographic realm) and global extents, using the same sets of faunal sample units for all four groups in each comparison. Beta diversity is lower for the two endothermic taxa (birds and mammals) than for the two ectothermic taxa (reptiles and amphibians) in all six biogeographic realms examined. When the four taxa in the six biogeographic realms are combined, beta diversity at the species rank is higher than that of the genus rank by a factor of 1.24, and is higher than that of the family rank by a factor of 1.85. The ratio of beta diversity at the genus rank to that at the family rank is 1.50. Beta diversity is slightly higher for ecoregious of 5000-99,999 km2 than for ecoregions of 100,000-5,000,000 km2.

  20. A trans-Amazonian screening of mtDNA reveals deep intraspecific divergence in forest birds and suggests a vast underestimation of species diversity.

    Science.gov (United States)

    Milá, Borja; Tavares, Erika S; Muñoz Saldaña, Alberto; Karubian, Jordan; Smith, Thomas B; Baker, Allan J

    2012-01-01

    The Amazonian avifauna remains severely understudied relative to that of the temperate zone, and its species richness is thought to be underestimated by current taxonomy. Recent molecular systematic studies using mtDNA sequence reveal that traditionally accepted species-level taxa often conceal genetically divergent subspecific lineages found to represent new species upon close taxonomic scrutiny, suggesting that intraspecific mtDNA variation could be useful in species discovery. Surveys of mtDNA variation in Holarctic species have revealed patterns of variation that are largely congruent with species boundaries. However, little information exists on intraspecific divergence in most Amazonian species. Here we screen intraspecific mtDNA genetic variation in 41 Amazonian forest understory species belonging to 36 genera and 17 families in 6 orders, using 758 individual samples from Ecuador and French Guiana. For 13 of these species, we also analyzed trans-Andean populations from the Ecuadorian Chocó. A consistent pattern of deep intraspecific divergence among trans-Amazonian haplogroups was found for 33 of the 41 taxa, and genetic differentiation and genetic diversity among them was highly variable, suggesting a complex range of evolutionary histories. Mean sequence divergence within families was the same as that found in North American birds (13%), yet mean intraspecific divergence in Neotropical species was an order of magnitude larger (2.13% vs. 0.23%), with mean distance between intraspecific lineages reaching 3.56%. We found no clear relationship between genetic distances and differentiation in plumage color. Our results identify numerous genetically and phenotypically divergent lineages which may result in new species-level designations upon closer taxonomic scrutiny and thorough sampling, although lineages in the tropical region could be older than those in the temperate zone without necessarily representing separate species. In-depth phylogeographic surveys

  1. A trans-Amazonian screening of mtDNA reveals deep intraspecific divergence in forest birds and suggests a vast underestimation of species diversity.

    Directory of Open Access Journals (Sweden)

    Borja Milá

    Full Text Available The Amazonian avifauna remains severely understudied relative to that of the temperate zone, and its species richness is thought to be underestimated by current taxonomy. Recent molecular systematic studies using mtDNA sequence reveal that traditionally accepted species-level taxa often conceal genetically divergent subspecific lineages found to represent new species upon close taxonomic scrutiny, suggesting that intraspecific mtDNA variation could be useful in species discovery. Surveys of mtDNA variation in Holarctic species have revealed patterns of variation that are largely congruent with species boundaries. However, little information exists on intraspecific divergence in most Amazonian species. Here we screen intraspecific mtDNA genetic variation in 41 Amazonian forest understory species belonging to 36 genera and 17 families in 6 orders, using 758 individual samples from Ecuador and French Guiana. For 13 of these species, we also analyzed trans-Andean populations from the Ecuadorian Chocó. A consistent pattern of deep intraspecific divergence among trans-Amazonian haplogroups was found for 33 of the 41 taxa, and genetic differentiation and genetic diversity among them was highly variable, suggesting a complex range of evolutionary histories. Mean sequence divergence within families was the same as that found in North American birds (13%, yet mean intraspecific divergence in Neotropical species was an order of magnitude larger (2.13% vs. 0.23%, with mean distance between intraspecific lineages reaching 3.56%. We found no clear relationship between genetic distances and differentiation in plumage color. Our results identify numerous genetically and phenotypically divergent lineages which may result in new species-level designations upon closer taxonomic scrutiny and thorough sampling, although lineages in the tropical region could be older than those in the temperate zone without necessarily representing separate species. In

  2. Hyperdominance in Amazonian forest carbon cycling

    NARCIS (Netherlands)

    Fauset, S.; Arets, E.J.M.M.; Steege, ter H.; Pena Claros, M.; Poorter, L.; Levis, C.; Toledo, M.

    2015-01-01

    While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant’ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem

  3. 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 spread of the pathogenic fungal disease chytridiomycosis. Here we assess the spatial distribution and interactions of these primary threats in relation to the global distribution of amphibian species. We show that the greatest proportions of species negatively affected by climate change are projected...... to be found in Africa, parts of northern South America and the Andes. Regions with the highest projected impact of land-use and climate change coincide, but there is little spatial overlap with regions highly threatened by the fungal disease. Overall, the areas harbouring the richest amphibian faunas...

  4. Diversity and composition of Amazonian moths in primary, secondary and plantation forests.

    OpenAIRE

    Hawes, Joseph; da Silva Motta, Catarina; Overal, William L.; Barlow, Jos; Gardner, Toby A.; Peres, Carlos A.

    2009-01-01

    The response of tropical fauna to landscape-level habitat change is poorly understood. Increased conversion of native primary forest to alternative land-uses, including secondary forest and exotic tree plantations, highlights the importance of assessing diversity patterns within these forest types. We sampled 1848 moths from 335 species of Arctiidae, Saturniidae and Sphingidae, over a total of 30 trap-nights. Sampling was conducted during the wet season 2005, using three light-traps at 15 sit...

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

    Science.gov (United States)

    Hof, Christian; Araújo, Miguel B; Jetz, Walter; Rahbek, Carsten

    2011-11-16

    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 spread of the pathogenic fungal disease chytridiomycosis. Here we assess the spatial distribution and interactions of these primary threats in relation to the global distribution of amphibian species. We show that the greatest proportions of species negatively affected by climate change are projected to be found in Africa, parts of northern South America and the Andes. Regions with the highest projected impact of land-use and climate change coincide, but there is little spatial overlap with regions highly threatened by the fungal disease. Overall, the areas harbouring the richest amphibian faunas 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 suggested.

  6. 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...

  7. Abundance, diversity, and patterns of distribution of primates on the Tapiche River in Amazonian Peru.

    Science.gov (United States)

    Bennett, C L; Leonard, S; Carter, S

    2001-06-01

    This work presents data on the relative diversity, abundance, and distribution patterns of primates in a 20 km2 area of the Tapiche River in the Peruvian Amazon. Population data were collected while the study area was both inundated and dry (March to September 1997) using conventional line-transect census techniques. Survey results reflected the presence of 11 primate species, but population parameters on only eight of the species will be presented, including saddleback tamarins (Saguinus fuscicollis), Bolivian squirrel monkeys (Saimiri boliviensis), brown capuchins (Cebus apella), white-fronted capuchins (Cebus albifrons), monk sakis (Pithecia monachus), red titi monkeys (Callicebus cupreus), red uakaris (Cacajao calvus), and red howler monkeys (Alouatta seniculus). Woolly monkeys (Lagothrix lagotricha), night monkeys (Aotus nancymaae), and pygmy marmosets (Callithrix pygmaea) were also seen in the area. The data for the smaller-bodied primates is similar to that reported almost 18 years earlier, but the data for the larger-bodied primates reflect a loss in the number of animals present in the area. Pressure from hunters and the timber industry may account for declining numbers of large-bodied primates, while it appears that natural features peculiar to the conservation area contribute to the patchy pattern of distribution. PMID:11376449

  8. Diversity of pulsed field gel electrophoresis pulsotypes, serovars and antibiotic resistance among Salmonella isolates from wild amphibians and reptiles in the California central coast

    Science.gov (United States)

    A survey of cold-blooded vertebrates and associated surface waters in a produce-growing region on the Central California Coast was done between May and September, 2011 to determine the diversity of Salmonella strains in these habitats and individuals. Samples from 460 amphibians and reptiles and 119...

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

    Directory of Open Access Journals (Sweden)

    Acevedo, A. A.

    2016-01-01

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

  10. Comparative Phylogeography Reveals Cryptic Diversity and Repeated Patterns of Cladogenesis for Amphibians and Reptiles in Northwestern Ecuador

    Science.gov (United States)

    Pyron, R. Alexander; Peñafiel, Nicolás; Romero-Barreto, Paulina; Culebras, Jaime; Bustamante, Lucas; Yánez-Muñoz, Mario H.; Guayasamin, Juan M.

    2016-01-01

    Comparative phylogeography allow us to understand how shared historical circumstances have shaped the formation of lineages, by examining a broad spectrum of co-distributed populations of different taxa. However, these types of studies are scarce in the Neotropics, a region that is characterized by high diversity, complex geology, and poorly understood biogeography. Here, we investigate the diversification patterns of five lineages of amphibians and reptiles, co-distributed across the Choco and Andes ecoregions in northwestern Ecuador. Mitochondrial DNA and occurrence records were used to determine the degree of geographic genetic divergence within species. Our results highlight congruent patterns of parapatric speciation and common geographical barriers for distantly related taxa. These comparisons indicate similar biological and demographic characteristics for the included clades, and reveal the existence of two new species of Pristimantis previously subsumed under P. walkeri, which we describe herein. Our data supports the hypothesis that widely distributed Chocoan taxa may generally experience their greatest opportunities for isolation and parapatric speciation across thermal elevational gradients. Finally, our study provides critical information to predict which unstudied lineages may harbor cryptic diversity, and how geology and climate are likely to have shaped their evolutionary history. PMID:27120100

  11. Comparative Phylogeography Reveals Cryptic Diversity and Repeated Patterns of Cladogenesis for Amphibians and Reptiles in Northwestern Ecuador.

    Directory of Open Access Journals (Sweden)

    Alejandro Arteaga

    Full Text Available Comparative phylogeography allow us to understand how shared historical circumstances have shaped the formation of lineages, by examining a broad spectrum of co-distributed populations of different taxa. However, these types of studies are scarce in the Neotropics, a region that is characterized by high diversity, complex geology, and poorly understood biogeography. Here, we investigate the diversification patterns of five lineages of amphibians and reptiles, co-distributed across the Choco and Andes ecoregions in northwestern Ecuador. Mitochondrial DNA and occurrence records were used to determine the degree of geographic genetic divergence within species. Our results highlight congruent patterns of parapatric speciation and common geographical barriers for distantly related taxa. These comparisons indicate similar biological and demographic characteristics for the included clades, and reveal the existence of two new species of Pristimantis previously subsumed under P. walkeri, which we describe herein. Our data supports the hypothesis that widely distributed Chocoan taxa may generally experience their greatest opportunities for isolation and parapatric speciation across thermal elevational gradients. Finally, our study provides critical information to predict which unstudied lineages may harbor cryptic diversity, and how geology and climate are likely to have shaped their evolutionary history.

  12. 云南省镇沅县两栖动物多样性研究%Study on the Diversity of Amphibians in Zhenyuan County of Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    李奇生; 张庆; 周杰珑; 杨丽萍

    2012-01-01

    Amphibian habitat is divided into residential areas, paddy field, lakes, rivers, woodlands and forest stream in Zhenyuan County of Yunnan Province, and different habitats were surveyed by setting transects. 10m×l000 m belt transects were designed and 50 transects were involved. Finally, 2096 amphibians were recorded, which belongs to 2 orders, 7 families 22 species; the diversity of amphibians in each habitat was evaluated using Shannon-weaver index and Pielou index, and the relationship of the habitat of amphibians and the human activities with amphibian diversity were also discussed.%对云南省镇沅县两栖动物生境的居民区、水田、湖泊、农地溪流、林地以及林区山涧等不同生境进行样带调查,设计样带10m×1000m,共涉及调查样带50条.共记录两栖动物2096只,隶属2目、7科、22种;利用物种多样性测定法(Shannon-weaver index & Pielou index)评价了各生境条件下两栖动物的多样性,并进一步探讨了两栖动物物种多样性与栖息环境的关系及其与人类活动干扰程度的关系.

  13. 泉州市两栖动物物种多样性研究%Research on Species Diversity of Amphibian Species in Quanzhou City

    Institute of Scientific and Technical Information of China (English)

    何中声; 刘金福; 洪伟; 王智苑; 郑雯; 杨文晖

    2012-01-01

    A survey of amphibian species of Quanzhou City was conducted and the diversity of amphibian species was assessed by using diversity indices and G-Findex. Also the cluster analysis of amphibian species' geographical distribution was studied in Quanzhou City. The results showed that there were thirty-two species amphibian in Quanzhou City, belonging to eleven geners, seven families and two orders. The species diversity of amphibian species in different City was significant. Amphibian species in Dehua was the most including 27 species, the second ones were Yongchun including 17 species and the area of Licheng and Shishi was the least including only 3 species because of the amphibian habitat was severely destroyed by the industry development. The G-F indices of amphibian species in Dehua was the highest value with /'-index 3.54 and C-index 2.43 among all the districts of Quanzhou area, while those of G-F indices was the lowest with F-index 0.69 and C-index 0.33 in Licheng and Shishi. The cluster analysis showed that the distribution of amphibian species in Quanzhou City was effected by the factors of geographical position, temperature and climates. The results could provide a scientific basis for amphibian species conservation and monitor in Quanzhou City.%通过对福建省泉州市两栖动物资源进行调查,采用物种多样性指数和G-F指数对泉州市两栖动物多样性进行评估以及对其地理分布进行了聚类分析.结果表明,泉州市两栖动物共计32种,隶属2目7科11属;各地区的两栖类物种多样性差异较大,德化两栖动物的种类最多,为27种,其次是永春,为17种,物种数最少的分别是鲤城和石狮,均为3种.其中德化两栖类的F指数达3.54,G指数达2.43,为泉州地区最高,鲤城和石狮的F指数(0.69)和G指数(0.33)均为泉州地区的最低值;聚类分析表明两栖动物在泉州地区的分布主要受地理位置、温度和气候等因素影响.研究结果为泉州市两栖动

  14. 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.

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

    Science.gov (United States)

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

    2013-08-01

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

  16. Hyperdominance in Amazonian forest carbon cycling

    OpenAIRE

    Fauset, Sophie; Johnson, Michelle O.; Gloor, Manuel; Baker, Timothy R.; Monteagudo M., Abel; Brienen, Roel J.W.; Feldpausch, Ted R.; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; Ter Steege, Hans; Pitman, Nigel C. A.; Baraloto, Christopher; Engel,Julien; Petronelli, Pascal; Andrade, Ana

    2015-01-01

    While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few â € hyperdominantâ €™ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the mos...

  17. Filling data gaps on the diversity and distribution of Amazonian bats (Chiroptera): the case of Amapá, easternmost Brazil

    OpenAIRE

    Ana C. M. Martins; Enrico Bernard; Renato Gregorin; Wanuyze A. S. da Silva

    2011-01-01

    Brazil is the second most bat species-rich country in the world, but the information on its species diversity, occurrence and distribution is still heterogeneous and fragmented. None of the Brazilian biomes are well surveyed for bats, but this situation is more critical in Amazonia, an area covering nearly 2/3 of the country. Here we provide updated information on the bats of Amapá, once a data gap in the diversity and distribution of bats in the easternmost Amazonia, and the Guiana Shield as...

  18. How much effort should be employed for surveying a low-diversity Amazonian mammal assemblage using line-transects?

    Directory of Open Access Journals (Sweden)

    Ítalo Mourthé

    2013-02-01

    Full Text Available Line-transect surveys are commonly used for sampling large mammals, but estimates of the effort needed to reliably surveying low-diversity assemblages of mammals are scarce. Using data from line-transects and species accumulation curves, I examined whether or not a sampling effort previously suggested to survey mammals elsewhere (ca. 85-100 km would be satisfactory for surveying a low-diversity assemblage of large mammals in the Rio Negro basin in northern Amazonia. In total, 14 mammals were recorded after an accumulated effort of 690 km walked. The desired threshold of completeness was only achieved in one of six transects after an average effort of 115 km surveyed. Considering the entire landscape (all transects pooled, survey completeness was reached after a much higher effort. Moreover, the theoretical effort required to achieve completeness was estimated to be 150-360 km per transect, and 512 km for the landscape. Further studies are required to fully understand this issue, but meanwhile it is safest to assume that higher sampling efforts should be employed when surveying low-diversity assemblages through diurnal line-transects in northwestern Amazonia to get robust estimates of mammal richness.

  19. Filling data gaps on the diversity and distribution of Amazonian bats (Chiroptera: the case of Amapá, easternmost Brazil

    Directory of Open Access Journals (Sweden)

    Ana C. M. Martins

    2011-04-01

    Full Text Available Brazil is the second most bat species-rich country in the world, but the information on its species diversity, occurrence and distribution is still heterogeneous and fragmented. None of the Brazilian biomes are well surveyed for bats, but this situation is more critical in Amazonia, an area covering nearly 2/3 of the country. Here we provide updated information on the bats of Amapá, once a data gap in the diversity and distribution of bats in the easternmost Amazonia, and the Guiana Shield as well. Rapid biological assessments (5,551 mistnet.hours were conducted in conservation units and areas of concern, resulting in 1,695 captures, 59 species, 36 genera and six families for the State. New records for the state and for the Guiana Shield area are reported. With our records, 82 species of bats are currently known in Amapá, filling a gap in the knowledge of bat fauna in the Amazon River's delta region.

  20. Molecular-based rapid inventories of sympatric diversity: a comparison of DNA barcode clustering methods applied to geography-based vs clade-based sampling of amphibians.

    Science.gov (United States)

    Paz, Andrea; Crawford, Andrew J

    2012-11-01

    Molecular markers offer a universal source of data for quantifying biodiversity. DNA barcoding uses a standardized genetic marker and a curated reference database to identify known species and to reveal cryptic diversity within wellsampled clades. Rapid biological inventories, e.g. rapid assessment programs (RAPs), unlike most barcoding campaigns, are focused on particular geographic localities rather than on clades. Because of the potentially sparse phylogenetic sampling, the addition of DNA barcoding to RAPs may present a greater challenge for the identification of named species or for revealing cryptic diversity. In this article we evaluate the use of DNA barcoding for quantifying lineage diversity within a single sampling site as compared to clade-based sampling, and present examples from amphibians. We compared algorithms for identifying DNA barcode clusters (e.g. species, cryptic species or Evolutionary Significant Units) using previously published DNA barcode data obtained from geography-based sampling at a site in Central Panama, and from clade-based sampling in Madagascar. We found that clustering algorithms based on genetic distance performed similarly on sympatric as well as clade-based barcode data, while a promising coalescent-based method performed poorly on sympatric data. The various clustering algorithms were also compared in terms of speed and software implementation. Although each method has its shortcomings in certain contexts, we recommend the use of the ABGD method, which not only performs fairly well under either sampling method, but does so in a few seconds and with a user-friendly Web interface.

  1. Molecular-based rapid inventories of sympatric diversity: A comparison of DNA barcode clustering methods applied to geography-based vs clade-based sampling of amphibians

    Indian Academy of Sciences (India)

    Andrea Paz; Andrew J Crawford

    2012-11-01

    Molecular markers offer a universal source of data for quantifying biodiversity. DNA barcoding uses a standardized genetic marker and a curated reference database to identify known species and to reveal cryptic diversity within well-sampled clades. Rapid biological inventories, e.g. rapid assessment programs (RAPs), unlike most barcoding campaigns, are focused on particular geographic localities rather than on clades. Because of the potentially sparse phylogenetic sampling, the addition of DNA barcoding to RAPs may present a greater challenge for the identification of named species or for revealing cryptic diversity. In this article we evaluate the use of DNA barcoding for quantifying lineage diversity within a single sampling site as compared to clade-based sampling, and present examples from amphibians. We compared algorithms for identifying DNA barcode clusters (e.g. species, cryptic species or Evolutionary Significant Units) using previously published DNA barcode data obtained from geography-based sampling at a site in Central Panama, and from clade-based sampling in Madagascar. We found that clustering algorithms based on genetic distance performed similarly on sympatric as well as clade-based barcode data, while a promising coalescent-based method performed poorly on sympatric data. The various clustering algorithms were also compared in terms of speed and software implementation. Although each method has its shortcomings in certain contexts, we recommend the use of the ABGD method, which not only performs fairly well under either sampling method, but does so in a few seconds and with a user-friendly Web interface.

  2. 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 ...

  3. Assessment of platyhelminth diversity within amphibians of French Guiana revealed a new species of Nanopolystoma (Monogenea: Polystomatidae) in the caecilian Typhlonectes compressicauda

    OpenAIRE

    du Preez, Louis H.; Badets, Mathieu; Verneau, Olivier

    2014-01-01

    Scientists attending the First World Congress of Her-petology in 1989 first became concerned about a widespread decline in amphibian population numbers (Stuart et al. 2004). Since then, the number of studies and publications on amphibians increased considerably and the number of species known nearly doubled to the current figure of 7 044 (Frost 2013). In their comprehensive study to identify biodiversity hotspots for conservation priorities , Meyers et al. (2000) reported on the unique biodiv...

  4. Floristic composition and diversity of Amazonian rainforest bryophytes in the state of Acre, Brazil Composição florística e diversidade de briófitas em floresta no estado do Acre, Brasil

    Directory of Open Access Journals (Sweden)

    Denise Pinheiro da Costa

    2003-01-01

    Full Text Available Bryophyte diversity in Amazonian Brazil is high, presently recorded at 514 species distributed among 36 families and 89 genera. Comparisions of species richness among the Amazonian states of Brazil suggests that the bryoflora of Acre is still underestimated, presently recorded at 106 species distributed among 33 families and 63 genera. After two field trips, the diversity increased 50% showing that the bryoflora is still poorly known. Collection data and comments on morphology, ecology and distribution are given for sixty-two species of bryophytes collected in the state of Acre, Brazil, which are new (fifty-two species or interesting floristic records (ten species. Microlejeunea crenulifolia (Gottsche Steph. and Stictolejeunea balfourdii Mitt. are new records for Brazil and fifty species are new records for Acre.A diversidade de briófitas na região Amazônica brasileira é alta, sendo citado atualmente, 514 espécies, em 36 famílias e 89 gêneros. Comparações entre a riqueza de espécies dos estados da Amazônia brasileira sugerem que a brioflora do Acre ainda é subestimada, contando atualmente com 106 espécies, distribuídas em 33 famílias e 63 gêneros. Após duas excursões científicas, a diversidade para o estado aumentou em 50 %, demonstrando que a brioflora ainda é pouco conhecida. Dados sobre a morfologia, ecologia e distribuição geográfica são apresentados para sessenta e duas espécies de briófitas coletadas no estado do Acre, Brasil, as quais são registros florísticos novos (cinquenta e duas espécies ou interessantes (dez espécies. Microlejeunea crenulifolia (Gottsche Steph. e Stictolejeunea balfourdii Mitt. são citadas pela primeira vez para o Brasil e cinquenta espécies são novas ocorrências para o estado do Acre.

  5. Joint simulation of carbon and tree diversity dynamics in an Amazonian forest succession using TROLL, an individual-based forest dynamics model

    Science.gov (United States)

    Maréchaux, Isabelle; Chave, Jérôme

    2016-04-01

    Amazonian forests are critical for biogeochemical cycles and provide also key ecosystem services. One approach for modelling forest vegetation dynamics is to parameterize species using field-measured plant traits in individual-based forest growth simulators, a method that has been successfully implemented in temperate forests. Here we extend this approach to the tropics. We parameterized the forest dynamics simulator TROLL over a hundred species and simulated the first decades of an ecological succession with tree species encountered in the coastal zone of French Guiana. The model reproduced well the empirically measured values of gross and net primary productivities (GPP and NPP, obtained from eddy-flux measurements) as well as canopy structure (obtained from aerial LiDAR scanning). Modelled species trajectories compared well with empirically measured ones at a clear-cut site for the past four decades. Modelled carbon accumulation curves show that forests are not mature even after 100 years of regeneration. Finally, we discuss how plant hydrology and responses to drought can be integrated into this modelling scheme using data from leaf water potential at wilting point.

  6. Diversity of pulsed-field gel electrophoresis pulsotypes, serovars, and antibiotic resistance among Salmonella isolates from wild amphibians and reptiles in the California Central Coast.

    Science.gov (United States)

    Gorski, Lisa; Jay-Russell, Michele T; Liang, Anita S; Walker, Samarpita; Bengson, Yingjia; Govoni, Jessica; Mandrell, Robert E

    2013-06-01

    A survey of cold-blooded vertebrates and associated surface waters in a produce-growing region on the Central California Coast was done between May and September 2011 to determine the diversity of Salmonella. Samples from 460 amphibians and reptiles and 119 water samples were collected and cultured for Salmonella. Animals sampled were frogs (n=331), lizards (n=59), newts (n=5), salamanders (n=6), snakes (n=39), and toads (n=20). Salmonella was isolated from 37 individual animals, including frogs, lizards, snakes, and toads. Snakes were the most likely to contain Salmonella, with 59% testing positive followed by 15.3% of lizards, 5% of toads, and 1.2% of frogs. Fifteen water samples (12.6%) were positive. Twenty-two different serovars were identified, and the majority of isolates were S. enterica subsp. IIIb, with subsp. I, II, and IIIa also found. The serovar isolated most frequently was S. enterica subsp. IIIb 16:z₁₀:e,n,x,z₁₅, from snakes and frogs in five different locations. S. enterica subsp. I serovar Typhimurium and the monophasic I 6,8:d:- were isolated from water, and subspecies I Duisburg and its variants were found in animals and water. Some samples contained more than one type of Salmonella. Analysis of pulsed-field gel electrophoresis pulsotypes indicated that some strains persisted in animals and water collected from the same location. Sixty-six isolates displayed antibiotic resistance, with 27 isolates resistant to more than one antibiotic, including a subspecies IIIb isolate from snake having resistance to five different antibiotics. Twenty-three isolates were resistant to more than one class of antibiotic, and six isolates were resistant to three classes. While these subspecies of IIIa and IIIb cause fewer instances of human illness, they may serve as reservoirs of antibiotic resistance, determinants in the environment, and be sources of contamination of leafy greens associated with product recalls.

  7. Cardiovascular physiology and diseases of amphibians.

    Science.gov (United States)

    Heinz-Taheny, Kathleen M

    2009-01-01

    The class Amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. The diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). This article provides a review of amphibian cardiovascular anatomy and physiology with discussion of unique species adaptations. In addition, amphibians as cardiovascular animal models and commonly encountered natural diseases are covered.

  8. 3D computational mechanics elucidate the evolutionary implications of orbit position and size diversity of early amphibians.

    Science.gov (United States)

    Marcé-Nogué, Jordi; Fortuny, Josep; De Esteban-Trivigno, Soledad; Sánchez, Montserrat; Gil, Lluís; Galobart, Àngel

    2015-01-01

    For the first time in vertebrate palaeontology, the potential of joining Finite Element Analysis (FEA) and Parametrical Analysis (PA) is used to shed new light on two different cranial parameters from the orbits to evaluate their biomechanical role and evolutionary patterns. The early tetrapod group of Stereospondyls, one of the largest groups of Temnospondyls is used as a case study because its orbits position and size vary hugely within the members of this group. An adult skull of Edingerella madagascariensis was analysed using two different cases of boundary and loading conditions in order to quantify stress and deformation response under a bilateral bite and during skull raising. Firstly, the variation of the original geometry of its orbits was introduced in the models producing new FEA results, allowing the exploration of the ecomorphology, feeding strategy and evolutionary patterns of these top predators. Secondly, the quantitative results were analysed in order to check if the orbit size and position were correlated with different stress patterns. These results revealed that in most of the cases the stress distribution is not affected by changes in the size and position of the orbit. This finding supports the high mechanical plasticity of this group during the Triassic period. The absence of mechanical constraints regarding the orbit probably promoted the ecomorphological diversity acknowledged for this group, as well as its ecological niche differentiation in the terrestrial Triassic ecosystems in clades as lydekkerinids, trematosaurs, capitosaurs or metoposaurs.

  9. 3D computational mechanics elucidate the evolutionary implications of orbit position and size diversity of early amphibians.

    Science.gov (United States)

    Marcé-Nogué, Jordi; Fortuny, Josep; De Esteban-Trivigno, Soledad; Sánchez, Montserrat; Gil, Lluís; Galobart, Àngel

    2015-01-01

    For the first time in vertebrate palaeontology, the potential of joining Finite Element Analysis (FEA) and Parametrical Analysis (PA) is used to shed new light on two different cranial parameters from the orbits to evaluate their biomechanical role and evolutionary patterns. The early tetrapod group of Stereospondyls, one of the largest groups of Temnospondyls is used as a case study because its orbits position and size vary hugely within the members of this group. An adult skull of Edingerella madagascariensis was analysed using two different cases of boundary and loading conditions in order to quantify stress and deformation response under a bilateral bite and during skull raising. Firstly, the variation of the original geometry of its orbits was introduced in the models producing new FEA results, allowing the exploration of the ecomorphology, feeding strategy and evolutionary patterns of these top predators. Secondly, the quantitative results were analysed in order to check if the orbit size and position were correlated with different stress patterns. These results revealed that in most of the cases the stress distribution is not affected by changes in the size and position of the orbit. This finding supports the high mechanical plasticity of this group during the Triassic period. The absence of mechanical constraints regarding the orbit probably promoted the ecomorphological diversity acknowledged for this group, as well as its ecological niche differentiation in the terrestrial Triassic ecosystems in clades as lydekkerinids, trematosaurs, capitosaurs or metoposaurs. PMID:26107295

  10. 3D computational mechanics elucidate the evolutionary implications of orbit position and size diversity of early amphibians.

    Directory of Open Access Journals (Sweden)

    Jordi Marcé-Nogué

    Full Text Available For the first time in vertebrate palaeontology, the potential of joining Finite Element Analysis (FEA and Parametrical Analysis (PA is used to shed new light on two different cranial parameters from the orbits to evaluate their biomechanical role and evolutionary patterns. The early tetrapod group of Stereospondyls, one of the largest groups of Temnospondyls is used as a case study because its orbits position and size vary hugely within the members of this group. An adult skull of Edingerella madagascariensis was analysed using two different cases of boundary and loading conditions in order to quantify stress and deformation response under a bilateral bite and during skull raising. Firstly, the variation of the original geometry of its orbits was introduced in the models producing new FEA results, allowing the exploration of the ecomorphology, feeding strategy and evolutionary patterns of these top predators. Secondly, the quantitative results were analysed in order to check if the orbit size and position were correlated with different stress patterns. These results revealed that in most of the cases the stress distribution is not affected by changes in the size and position of the orbit. This finding supports the high mechanical plasticity of this group during the Triassic period. The absence of mechanical constraints regarding the orbit probably promoted the ecomorphological diversity acknowledged for this group, as well as its ecological niche differentiation in the terrestrial Triassic ecosystems in clades as lydekkerinids, trematosaurs, capitosaurs or metoposaurs.

  11. Fungal community assembly in the Amazonian Dark Earth

    NARCIS (Netherlands)

    Lucheta, A.R.; Souza Cannavan, F.S.; Roesch, L.; Tsai, S.M.; Kuramae, E.E.

    2016-01-01

    Here, we compare the fungal community composition and diversity in Amazonian Dark Earth (ADE) and the respective non-anthropogenic origin adjacent (ADJ) soils from four different sites in Brazilian Central Amazon using pyrosequencing of 18S ribosomal RNA (rRNA) gene. Fungal community composition in

  12. The odd man out? Might climate explain the lower tree alpha-diversity of African rain forests relative to Amazonian rain forests?

    NARCIS (Netherlands)

    Parmentier, I.; Malhi, Y.; Senterre, B.; Whittaker, R.J.; Alonso, A.; Balinga, M.P.B.; Bakayoko, A.; Bongers, F.J.J.M.; Chatelain, C.; Comiskey, J.; Cortay, R.; Djuikouo Kamdem, M.N.; Doucet, J.L.; Gauier, L.; Hawthorne, W.D.; Issembe, Y.A.; Kouamé, F.N.; Kouka, L.; Leal, M.E.; Lejoly, J.; Lewis, S.L.; Newbery, D.; Nusbaumer, L.; Parren, M.P.E.; Peh, K.S.H.; Phillips, O.L.; Sheil, D.; Sonké, B.; Sosef, M.S.M.; Sunderland, T.; Stropp, J.; Steege, ter H.; Swaine, M.; Tchouto, P.; Gemerden, van B.S.; Valkenburg, van J.; Wöll, H.

    2007-01-01

    1. Comparative analyses of diversity variation among and between regions allow testing of alternative explanatory models and ideas. Here, we explore the relationships between the tree alpha-diversity of small rain forest plots in Africa and in Amazonia and climatic variables, to test the explanatory

  13. Endoscopy in Amphibians.

    Science.gov (United States)

    Chai, Norin

    2015-09-01

    Despite advances in exotic animal endoscopy, descriptions involving amphibians are scarce. Amphibian endoscopy shares some similarities with reptiles, especially in lizards. Selected procedures are discussed, including stomatoscopy, gastroscopy, coelioscopy, and biopsy of coelomic organs and lesions. This short overview provides the practitioner with pragmatic advice on how to conduct safe and effective endoscopic examinations in amphibians.

  14. [Perspective on gravitational biology of amphibians].

    Science.gov (United States)

    Yamashita, Masamichi; Naitoh, Tomio; Wassersug, Richard J

    2002-12-01

    We review here the scientific significance of the use of amphibians for research in gravitational biology. Since amphibian eggs are quite large, yet develop rapidly and externally, it is easy to observe their development. Consequently amphibians were the first vertebrates to have their early developmental processes investigated in space. Though several deviations from normal embryonic development occur when amphibians are raised in microgravity, their developmental program is robust enough to return the organisms to an ostensibly normal morphology by the time they hatch. Evolutionally, amphibians were the first vertebrate animal to come out of the water and onto land. Subsequently they diversified and have adaptively radiated to various habitats. They now inhabit aquatic, terrestrial, arboreal and fossorial niches. This diversity can be used to help study the biological effects of gravity at the organismal level, where macroscopic phenomena are associated with gravitational loading. By choosing different amphibian models and using a comparative approach one can effectively identify the action of gravity on biological systems, and the adaptation that vertebrates have made to this loading. Advances in cellular and molecular biology provide powerful tools for the study in many fields, including gravitational biology, and amphibians have proven to be good models for studies at those levels as well. The low metabolic rates of amphibians make them convenient organisms to work with (compared to birds and mammals) in the difficult and confined spaces on orbiting research platforms. We include here a review of what is known about and the potential for further behavioral and physiological researches in space using amphibians.

  15. DNA barcoding survey of Trichoderma diversity in soil and litter of the Colombian lowland Amazonian rainforest reveals Trichoderma strigosellum sp. nov. and other species

    NARCIS (Netherlands)

    Lopez-Quintero, C.A.; Atanasova, L.; Franco-Molano, A.E.; Gams, W.; Komon-Zelazowska, M.; Theelen, B.; Muller, W.H.; Boekhout, T.; Druzhinina, I.

    2013-01-01

    The diversity of Trichoderma (Hypocreales, Ascomycota) colonizing leaf litter as well as the rhizosphere of Garcinia macrophylla (Clusiaceae) was investigated in primary and secondary rain forests in Colombian Amazonia. DNA barcoding of 107 strains based on the internal transcribed spacers 1 and 2 (

  16. Amphibians as animal models for laboratory research in physiology.

    Science.gov (United States)

    Burggren, Warren W; Warburton, Stephen

    2007-01-01

    The concept of animal models is well honored, and amphibians have played a prominent part in the success of using key species to discover new information about all animals. As animal models, amphibians offer several advantages that include a well-understood basic physiology, a taxonomic diversity well suited to comparative studies, tolerance to temperature and oxygen variation, and a greater similarity to humans than many other currently popular animal models. Amphibians now account for approximately 1/4 to 1/3 of lower vertebrate and invertebrate research, and this proportion is especially true in physiological research, as evident from the high profile of amphibians as animal models in Nobel Prize research. Currently, amphibians play prominent roles in research in the physiology of musculoskeletal, cardiovascular, renal, respiratory, reproductive, and sensory systems. Amphibians are also used extensively in physiological studies aimed at generating new insights in evolutionary biology, especially in the investigation of the evolution of air breathing and terrestriality. Environmental physiology also utilizes amphibians, ranging from studies of cryoprotectants for tissue preservation to physiological reactions to hypergravity and space exploration. Amphibians are also playing a key role in studies of environmental endocrine disruptors that are having disproportionately large effects on amphibian populations and where specific species can serve as sentinel species for environmental pollution. Finally, amphibian genera such as Xenopus, a genus relatively well understood metabolically and physiologically, will continue to contribute increasingly in this new era of systems biology and "X-omics."

  17. Surgery in Amphibians.

    Science.gov (United States)

    Chai, Norin

    2016-01-01

    Amphibian surgery has been especially described in research. Since the last decade, interest for captive amphibians has increased, so have the indications for surgical intervention. Clinicians should not hesitate to advocate such manipulations. Amphibian surgeries have no overwhelming obstacles. These patients heal well and tolerate blood loss more than higher vertebrates. Most procedures described in reptiles (mostly lizards) can be undertaken in most amphibians if equipment can be matched to the patients' size. In general, the most difficult aspect would be the provision of adequate anesthesia.

  18. DNA barcoding survey of Trichoderma diversity in soil and litter of the Colombian lowland Amazonian rainforest reveals Trichoderma strigosellum sp. nov. and other species.

    Science.gov (United States)

    López-Quintero, Carlos A; Atanasova, Lea; Franco-Molano, A Esperanza; Gams, Walter; Komon-Zelazowska, Monika; Theelen, Bart; Müller, Wally H; Boekhout, Teun; Druzhinina, Irina

    2013-11-01

    The diversity of Trichoderma (Hypocreales, Ascomycota) colonizing leaf litter as well as the rhizosphere of Garcinia macrophylla (Clusiaceae) was investigated in primary and secondary rain forests in Colombian Amazonia. DNA barcoding of 107 strains based on the internal transcribed spacers 1 and 2 (ITS1 and 2) of the ribosomal RNA gene cluster and the partial sequence of the translation elongation factor 1 alpha (tef1) gene revealed that the diversity of Trichoderma was dominated (71 %) by three common cosmopolitan species, namely Trichoderma harzianum sensu lato (41 %), Trichoderma spirale (17 %) and Trichoderma koningiopsis (13 %). Four ITS 1 and 2 phylotypes (13 strains) could not be identified with certainty. Multigene phylogenetic analysis and phenotype profiling of four strains with an ITS1 and 2 phylotype similar to Trichoderma strigosum revealed a new sister species of the latter that is described here as Trichoderma strigosellum sp. nov. Sequence similarity searches revealed that this species also occurs in soils of Malaysia and Cameroon, suggesting a pantropical distribution.

  19. 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 ...

  20. Diversidad de anfibios y reptiles de la Reserva de la Biosfera Barranca de Metztitlán, Hidalgo, México Diversity of amphibians and reptiles from the Barranca de Metztitlán Biosphera Reserve in Hidalgo, Mexico

    Directory of Open Access Journals (Sweden)

    Victor D. Vite-Silva

    2010-08-01

    scrubland. Field work was carried out between June 2006 and August 2007, a period spanning both wet and dry seasons. Overall, we found 7 species of amphibians and 31 species of reptiles in the BMBR, distributed in 14 families and 29 genera. Across all vegetation types, reptile species richness was greater in the rainy season, whereas amphibian species richness was greater in the dry season. Among vegetation types, tropical deciduous forest exhibited the highest diversity and richness of amphibians and reptiles. Pine-oak forest exhibited greatest species evenness and species diversity than the other vegetation types. Arid tropical scrubland and sub-montane shrubland were more similar to each other in species diversity. This study represents a significant addition to our knowledge of the herpetofauna from the BMBR, and an important base for future studies on the natural history of amphibians and reptiles in this reserve.

  1. Diversity of the land resources in the Amazonian State of Rondônia, Brazil Diversidade dos terrenos e solos do estado de Rondônia, Brasil

    Directory of Open Access Journals (Sweden)

    T.T. Cochrane

    2006-03-01

    Full Text Available Conflicting opinions are recorded in the literature concerning the suitability of Amazon lands for sustainable agriculture following deforestation. This article has been written to shed light on this question by summarizing climate, landform, soil and vegetation features from the findings of a land resource study of the Brazilian state of Rondônia in south-west Amazonia. The work, which followed the World Soils and Terrain Digital Database (SOTER methodology, was financed by the World Bank. During the course of the survey special emphasis was given to studying soils; 2914 profiles were analyzed and recorded. The study identified a complex pattern of land units with clear differences in climate, landform, soils and native vegetation. Forested areas mosaic with lesser areas of natural savannas. The latter occur on both poorly-drained and well-drained, albeit nutrient deficient sandy soils. The tallest and most vigorous forests or their remnants were seen growing on well-drained soils formed from nutrient-rich parent materials. Many of these soils could, or are being used for productive agriculture. Soils developed on nutrient-poor parent materials support forests that are significantly lower in height, and would require large lime and fertilizer inputs for agriculture. Low forests with high palm populations and minor areas of wet land savannas cover the poorly drained soils. It is evident that forest clearing in the past was indiscriminant; this cannot be condoned. The diversity of land conditions found throughout Rondônia would suggest that many past studies in the Amazon have simply been too broad to identify significant soil differences.Opiniões divergentes são encontradas na literatura com respeito ao uso de terras da Amazônia para agricultura sustentável apos desmatamento. Este artigo busca clarificar a questão com um resumo dos resultados de um estudo dos recursos naturais (clima, atributos de solos e terrenos, e vegetação do estado

  2. Reptiles and amphibians of a poorly known region in southwest Amazonia

    Directory of Open Access Journals (Sweden)

    Frederico Gustavo Rodrigues França

    2010-09-01

    Full Text Available The Amazon is the largest tropical forest of the world and it is extremely rich in biodiversity. However, some portions of the biome are still poorly known. This work presents an inventory of the herpetofauna of Boca do Acre municipality, a still preserved region located in southwest Amazonas state. The inventory was carried out in two periods, a sampling during the middle of the rainy season and another one at the end of the rains. Diverse survey methods were employed, such as pitfall traps, diurnal and nocturnal visual searches, car searches on the BR 317 highway, and opportunistic registrations. We recorded 56 amphibians and 53 reptiles during the field work. We captured 27 species in pitfall traps, and 38 were found along the BR 317, alive or dead on the road, being snakes principally affected by road-kills. The species accumulation curves did not reach stability, indicating that the inventory was not complete. Our results show the high species richness of this region, its importance for the Amazonian biodiversity, and the urgency of its preservation.

  3. 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

  4. Amphibian monitoring in the Atchafalaya Basin

    Science.gov (United States)

    Waddle, Hardin

    2011-01-01

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

  5. Antiviral immunity in amphibians.

    Science.gov (United States)

    Chen, Guangchun; Robert, Jacques

    2011-11-01

    Although a variety of virus species can infect amphibians, diseases caused by ranaviruses ([RVs]; Iridoviridae) have become prominent, and are a major concern for biodiversity, agriculture and international trade. The relatively recent and rapid increase in prevalence of RV infections, the wide range of host species infected by RVs, the variability in host resistance among population of the same species and among different developmental stages, all suggest an important involvement of the amphibian immune system. Nevertheless, the roles of the immune system in the etiology of viral diseases in amphibians are still poorly investigated. We review here the current knowledge of antiviral immunity in amphibians, focusing on model species such as the frog Xenopus and the salamander (Ambystoma tigrinum), and on recent progress in generating tools to better understand how host immune defenses control RV infections, pathogenicity, and transmission.

  6. AMPHIBIAN POPULATION DYNAMICS

    Science.gov (United States)

    Agriculture has contributed to loss of vertebrate biodiversity in many regions, including the U.S. Corn Belt. Amphibian populations, in particular, have experienced widespread and often inexplicable declines, range reductions, and extinctions. However, few attempts have been made...

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

    Science.gov (United States)

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

    2012-03-20

    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. We sampled 625 amphibians in December 2007 and February to March 2008, months that correspond to the early and intermediate breeding seasons for amphibians, respectively. We found 7 of 9 sampled species to be infected with Bd and found differences in prevalence between sampling periods. Although some amphibians tested had higher intensities of infection than others, all animals sampled were apparently healthy and, so far, there has been no evidence of either unusually high rates of mortality or amphibian population declines in the DNP.

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

    Science.gov (United States)

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

    2006-01-01

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

  9. Captive breeding, reintroduction, and the conservation of amphibians.

    Science.gov (United States)

    Griffiths, Richard A; Pavajeau, Lissette

    2008-08-01

    The global amphibian crisis has resulted in renewed interest in captive breeding as a conservation tool for amphibians. Although captive breeding and reintroduction are controversial management actions, amphibians possess a number of attributes that make them potentially good models for such programs. We reviewed the extent and effectiveness of captive breeding and reintroduction programs for amphibians through an analysis of data from the Global Amphibian Assessment and other sources. Most captive breeding and reintroduction programs for amphibians have focused on threatened species from industrialized countries with relatively low amphibian diversity. Out of 110 species in such programs, 52 were in programs with no plans for reintroduction that had conservation research or conservation education as their main purpose. A further 39 species were in programs that entailed captive breeding and reintroduction or combined captive breeding with relocations of wild animals. Nineteen species were in programs with relocations of wild animals only. Eighteen out of 58 reintroduced species have subsequently bred successfully in the wild, and 13 of these species have established self-sustaining populations. As with threatened amphibians generally, amphibians in captive breeding or reintroduction programs face multiple threats, with habitat loss being the most important. Nevertheless, only 18 out of 58 reintroduced species faced threats that are all potentially reversible. When selecting species for captive programs, dilemmas may emerge between choosing species that have a good chance of surviving after reintroduction because their threats are reversible and those that are doomed to extinction in the wild as a result of irreversible threats. Captive breeding and reintroduction programs for amphibians require long-term commitments to ensure success, and different management strategies may be needed for species earmarked for reintroduction and species used for conservation

  10. The role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines.

    Science.gov (United States)

    Rollins-Smith, Louise A

    2009-08-01

    Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked to a pathogenic skin fungus, Batrachochytrium dendrobatidis, or to iridoviruses of the genus Ranavirus. One of the first lines of defense against pathogens that enter by way of the skin are antimicrobial peptides synthesized and stored in dermal granular glands and secreted into the mucus following alarm or injury. Here, I review what is known about the capacity of amphibian antimicrobial peptides from diverse amphibians to inhibit B. dendrobatidis or ranavirus infections. When multiple species were compared for the effectiveness of their in vitro antimicrobial peptides defenses against B. dendrobatidis, non-declining species of rainforest amphibians had more effective antimicrobial peptides than species in the same habitat that had recently experienced population declines. Further, there was a significant correlation between the effectiveness of the antimicrobial peptides and resistance of the species to experimental infection. These studies support the hypothesis that antimicrobial peptides are an important component of innate defenses against B. dendrobatidis. Some amphibian antimicrobial peptides inhibit ranavirus infections and infection of human T lymphocytes by the human immunodeficiency virus (HIV). An effective antimicrobial peptide defense against skin pathogens appears to depend on a diverse array of genes expressing antimicrobial peptides. The production of antimicrobial peptides may be regulated by signals from the pathogens. However, this defense must also accommodate potentially beneficial microbes on the skin that compete or inhibit growth of the pathogens. How this delicate balancing act is accomplished is an important area of future research.

  11. Carbon storage in Amazonian podzols

    Science.gov (United States)

    Montes, Celia; Lucas, Yves; Pereira, Osvaldo; Merdy, Patricia; Santin, Roberta; Ishida, Débora; du Gardin, Beryl; Melfi, Adolpho

    2014-05-01

    It has recently been discovered that Amazonian podzols may store much larger quantities of carbon than previously thought, particularly in their deep Bh horizons (over 13.6 Pg for Brazilian Amazonia alone [1]). Similarly high carbon stocks are likely to exist in similar climate/soil areas, mainly in Africa and in Borneo. Such carbon stocks raise the problem of their stability in response to changes in land use or climate. Any significant changes in vegetation cover would significantly alter the soil water dynamics, which is likely to affect organic matter turnover in soils. The direction of the change, however, is not clear and is likely to depend on the specific conditions of carbon storage and properties of the soils. It is reasonable to assume that the drying of the Bh horizons of equatorial podzols, which are generally saturated, will lead to an increase in C mineralization, although the extent of this increase has not yet been determined. These unknowns resulted in research programs, granted by the Brazilian FAPESP and the French Région PACA-ARCUS and ANR, dedicated improving estimates of the Amazonian podzol carbon stocks and to an estimate of its mineralisability. Eight test areas were determined from the analysis of remote sensing data in the larger Amazonian podzol region located in the High Rio Negro catchment and studied in detail. Despite the extreme difficulties in carrying out the field work (difficulties in reaching the study sites and extracting the soils), more than a hundred points were sampled. In all podzols the presence of a thick deep Bh was confirmed, sometimes to depths greater than 12 m. The Bh carbon was quantified, indicating that carbon stocks in these podzols are even higher than estimated recently [1]. References 1- Montes, C.R.; Lucas, Y.; Pereira, O.J.R.; Achard, R.; Grimaldi, M.; Mefli, A.J. Deep plant?derived carbon storage in Amazonian podzols. Biogeosciences, 8, 113?120, 2011.

  12. Adaptive colouration in amphibians.

    Science.gov (United States)

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians.

  13. A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands

    Science.gov (United States)

    Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Wesselingh, Frank P.; Antoine, Pierre-Olivier

    2015-01-01

    Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman—Gnatusuchus pebasensis—bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene. PMID:25716785

  14. The world's richest tadpole communities show functional redundancy and low functional diversity: ecological data on Madagascar's stream-dwelling amphibian larvae

    OpenAIRE

    Randrianiaina Roger-Daniel; Reeve Erik; Strauß Axel; Vences Miguel; Glos Julian

    2010-01-01

    Abstract Background Functional diversity illustrates the range of ecological functions in a community. It allows revealing the appearance of functional redundancy in communities and processes of community assembly. Functional redundancy illustrates the overlap in ecological functions of community members which may be an indicator of community resilience. We evaluated patterns of species richness, functional diversity and functional redundancy on tadpole communities in rainforest streams in Ma...

  15. Food Plants Eaten by Amazonian Manatees (Trichechus inunguis, Mammalia : Sirenia

    Directory of Open Access Journals (Sweden)

    Colares Ioni G.

    2002-01-01

    Full Text Available To determine the feeding habits of the Amazonian manatee Trichechus inunguis in some Central Amazonian rivers and lakes, we compared plant epidermis found in the stomach contents and/or faeces of animals with a reference collection of plants present in the studied areas. Twenty five samples from digestive tracts of animals found dead and 25 faeces samples found floating were analyzed. From these samples, 24 aquatic macrophytes were identified. The Gramineae family was identified in 96% of the samples, Paspalum repens and Echinochloa polystachya being the most abundant in the samples. The second most frequent family was the Pontederiaceae primarily Eichhornia crassipes. During the high water period, the animals showed a more selective diet (eight identified species. In the low water period, when food was more scarce, the animals showed a larger diversity of species in their diet (21 species of plants. Differences in the diet among the two studied areas reflected the physiographics characteristics of the region. Amazonian manatees fed mostly on emergent plants.

  16. Amphibian skin may select for rare environmental microbes.

    Science.gov (United States)

    Walke, Jenifer B; Becker, Matthew H; Loftus, Stephen C; House, Leanna L; Cormier, Guy; Jensen, Roderick V; Belden, Lisa K

    2014-11-01

    Host-microbe symbioses rely on the successful transmission or acquisition of symbionts in each new generation. Amphibians host a diverse cutaneous microbiota, and many of these symbionts appear to be mutualistic and may limit infection by the chytrid fungus, Batrachochytrium dendrobatidis, which has caused global amphibian population declines and extinctions in recent decades. Using bar-coded 454 pyrosequencing of the 16S rRNA gene, we addressed the question of symbiont transmission by examining variation in amphibian skin microbiota across species and sites and in direct relation to environmental microbes. Although acquisition of environmental microbes occurs in some host-symbiont systems, this has not been extensively examined in free-living vertebrate-microbe symbioses. Juvenile bullfrogs (Rana catesbeiana), adult red-spotted newts (Notophthalmus viridescens), pond water and pond substrate were sampled at a single pond to examine host-specificity and potential environmental transmission of microbiota. To assess population level variation in skin microbiota, adult newts from two additional sites were also sampled. Cohabiting bullfrogs and newts had distinct microbial communities, as did newts across the three sites. The microbial communities of amphibians and the environment were distinct; there was very little overlap in the amphibians' core microbes and the most abundant environmental microbes, and the relative abundances of OTUs that were shared by amphibians and the environment were inversely related. These results suggest that, in a host species-specific manner, amphibian skin may select for microbes that are generally in low abundance in the environment.

  17. Universal COI primers for DNA barcoding amphibians.

    Science.gov (United States)

    Che, Jing; Chen, Hong-Man; Yang, Jun-Xiao; Jin, Jie-Qiong; Jiang, Ke; Yuan, Zhi-Yong; Murphy, Robert W; Zhang, Ya-Ping

    2012-03-01

    DNA barcoding is a proven tool for the rapid and unambiguous identification of species, which is essential for many activities including the vouchering tissue samples in the genome 10K initiative, genealogical reconstructions, forensics and biodiversity surveys, among many other applications. A large-scale effort is underway to barcode all amphibian species using the universally sequenced DNA region, a partial fragment of mitochondrial cytochrome oxidase subunit I COI. This fragment is desirable because it appears to be superior to 16S for barcoding, at least for some groups of salamanders. The barcoding of amphibians is essential in part because many species are now endangered. Unfortunately, existing primers for COI often fail to achieve this goal. Herein, we report two new pairs of primers (➀, ➁) that in combination serve to universally amplify and sequence all three orders of Chinese amphibians as represented by 36 genera. This taxonomic diversity, which includes caecilians, salamanders and frogs, suggests that the new primer pairs will universally amplify COI for the vast majority species of amphibians.

  18. The world's richest tadpole communities show functional redundancy and low functional diversity: ecological data on Madagascar's stream-dwelling amphibian larvae

    Directory of Open Access Journals (Sweden)

    Randrianiaina Roger-Daniel

    2010-05-01

    Full Text Available Abstract Background Functional diversity illustrates the range of ecological functions in a community. It allows revealing the appearance of functional redundancy in communities and processes of community assembly. Functional redundancy illustrates the overlap in ecological functions of community members which may be an indicator of community resilience. We evaluated patterns of species richness, functional diversity and functional redundancy on tadpole communities in rainforest streams in Madagascar. This habitat harbours the world's most species-rich stream tadpole communities which are due to their occurrence in primary habitat of particular interest for functional diversity studies. Results Species richness of tadpole communities is largely determined by characteristics of the larval habitat (stream structure, not by adult habitat (forest structure. Species richness is positively correlated with a size-velocity gradient of the streams, i.e. communities follow a classical species-area relationship. While widely observed for other taxa, this is an unusual pattern for anuran larvae which usually is expected to be hump-shaped. Along the species richness gradient, we quantified functional diversity of all communities considering the similarity and dissimilarity of species in 18 traits related to habitat use and foraging. Especially species-rich communities were characterised by an overlap of species function, i.e. by functional redundancy. By comparing the functional diversity of the observed communities with functional diversity of random assemblages, we found no differences at low species richness level, whereas observed species-rich communities have lower functional diversity than respective random assemblages. Conclusions We found functional redundancy being a feature of communities also in primary habitat, what has not been shown before using such a continuous measure. The observed species richness dependent pattern of low functional

  19. Conservation needs of amphibians in China: A review

    Institute of Scientific and Technical Information of China (English)

    XIE Feng; 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. Salamanders 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 likelihood 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.

  20. 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.

  1. Facility design and associated services for the study of amphibians.

    Science.gov (United States)

    Browne, Robert K; Odum, R Andrew; Herman, Timothy; Zippel, Kevin

    2007-01-01

    The role of facilities and associated services for amphibians has recently undergone diversification. Amphibians traditionally used as research models adjust well to captivity and thrive with established husbandry techniques. However, it is now necessary to maintain hundreds of novel amphibian species in captive breeding, conservation research, and biomedical research programs. These diverse species have a very wide range of husbandry requirements, and in many cases the ultimate survival of threatened species will depend on captive populations. Two critical factors have emerged in the maintenance of amphibians, stringent quarantine and high-quality water. Because exotic diseases such as chytridiomycosis have devastated both natural and captive populations of amphibians, facilities must provide stringent quarantine. The provision of high-quality water is also essential to maintain amphibian health and condition due to the intimate physiological relationship of amphibians to their aquatic environment. Fortunately, novel technologies backed by recent advances in the scientific knowledge of amphibian biology and disease management are available to overcome these challenges. For example, automation can increase the reliability of quarantine and maintain water quality, with a corresponding decrease in handling and the associated disease-transfer risk. It is essential to build facilities with appropriate nontoxic waterproof materials and to provide quarantined amphibian rooms for each population. Other spaces and services include live feed rooms, quarantine stations, isolation rooms, laboratory space, technical support systems, reliable energy and water supplies, high-quality feed, and security. Good husbandry techniques must include reliable and species-specific management by trained staff members who receive support from the administration. It is possible to improve husbandry techniques for many species by sharing knowledge through common information systems. Overall

  2. 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…

  3. Responding to Amphibian Loss

    NARCIS (Netherlands)

    J.R. Mendelson III; K.R. Lips; R.W. Gagliardo; G.B. Rabb; J.P. Collins; J.E. Diffendorfer; P. Daszak; R. Ibáñez D.; K.C. Zippel; D.P. Lawson; K.M. Wright; S.N. Stuart; C. Gascon; H.R. da Silva; P.A. Burrowes; R.L. Joglar; E. La Marca; S. Lötters; L.H. du Preez; C. Weldon; A. Hyatt; J.V. Rodriguez-Mahecha; S. Hunt; H. Robertson; B. Lock; C.J. Raxworthy; D.R. Frost; R.C. Lacy; R.A. Alford; J.A. Campbell; G. Parra-Olea; F. Bolaños; J.J. Calvo Domingo; T. Halliday; J.B. Murphy; M.H. Wake; L.A. Coloma; S.L. Kuzmin; M.S. Price; K.M. Howell; M. Lau; R. Pethiyagoda; M. Boone; M.J. Lannoo; A.R. Blaustein; A. Dobson; R.A. Griffiths; M.L. Crump; D.B. Wake; E.D. Brodie Jr

    2006-01-01

    In their Policy Forum "Confronting amphibian declines and extinctions" (7 July, p. 48), J. R. Mendelson III and colleagues offer a strategy for "stopping" the widespread losses of frogs, toads, and salamanders. Disease research and captive breeding figure prominently in their call for action.

  4. Mitochondrial DNA mapping of social-biological interactions in Brazilian Amazonian African-descendant populations

    Directory of Open Access Journals (Sweden)

    Bruno Maia Carvalho

    2008-01-01

    Full Text Available The formation of the Brazilian Amazonian population has historically involved three main ethnic groups, Amerindian, African and European. This has resulted in genetic investigations having been carried out using classical polymorphisms and molecular markers. To better understand the genetic variability and the micro-evolutionary processes acting in human groups in the Brazilian Amazon region we used mitochondrial DNA to investigate 159 maternally unrelated individuals from five Amazonian African-descendant communities. The mitochondrial lineage distribution indicated a contribution of 50.2% from Africans (L0, L1, L2, and L3, 46.6% from Amerindians (haplogroups A, B, C and D and a small European contribution of 1.3%. These results indicated high genetic diversity in the Amerindian and African lineage groups, suggesting that the Brazilian Amazonian African-descendant populations reflect a possible population amalgamation of Amerindian women from different Amazonian indigenous tribes and African women from different geographic regions of Africa who had been brought to Brazil as slaves. The present study partially mapped the historical biological and social interactions that had occurred during the formation and expansion of Amazonian African-descendant communities.

  5. 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.

  6. 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...

  7. Late Amazonian Glaciations in Utopia Planitia, Mars

    Science.gov (United States)

    Osinski, G. R.; Capitan, R. D.; Kerrigan, M.; Barry, N.; Blain, S.

    2012-03-01

    We present evidence from western Utopia Planitia, including lineated valley fill and lobate debris aprons, for widespread glaciations over a large expanse of the northern plains and dichotomy boundary during Late Amazonian times.

  8. Field Surveys of Amphibian Populations.

    Science.gov (United States)

    Brodman, Robert

    2000-01-01

    Describes a course on amphibian research for environmental science majors. Involves students in field studies and introduces them to investigative research. Evaluates the course. (Contains 19 references.) (YDS)

  9. Antimicrobial activity of amazonian medicinal plants

    OpenAIRE

    Oliveira, Amanda A; Segovia, Jorge FO; Sousa, Vespasiano YK; Mata, Elida CG; Gonçalves, Magda CA; Bezerra, Roberto M; Junior, Paulo OM; Kanzaki, Luís IB

    2013-01-01

    Objectives The aqueous extracts of currently utilized Amazonian medicinal plants were assayed in vitro searching for antimicrobial activity against human and animal pathogenic microorganisms. Methods Medium resuspended lyophilized aqueous extracts of different organs of Amazonian medicinal plants were assayed by in vitro screening for antimicrobial activity. ATCC and standardized microorganisms obtained from Oswaldo Cruz Foundation/Brazil were individually and homogeneously grown in agar plat...

  10. Moving beyond a snapshot to understand changes in the well-being of native Amazonians : panel evidence (2002-2006) from Bolivia.

    OpenAIRE

    Godoy, Ricardo; Reyes García, Victòria; Gravlee, Clarence C.; Huanca L., Tomás; Leonard, William R.; McDade, Thomas W.; Tanner, Susan

    2009-01-01

    Forces such as the opening of trade, globalization, multinational corporate resource extraction, urbanization, acculturation, and colonization catalyze economic, ecological, and sociocultural change, which can threaten the well‐being and habitat of native Amazonians. Understanding these forces is of paramount importance to improve the well‐being of native Amazonians and to foster the conservation of biological diversity, yet most analyses of these forces rely on cross‐sectional data. Though a...

  11. Amphibian and benthic macroinvertebrate response to physical and chemical properties of Themi River, Arusha, Tanzania

    OpenAIRE

    Lyimo, Emmanuel

    2012-01-01

    I hypothesized that variation in physical and chemical properties and habitat destruction of the Themi River as a result of human activities would affect abundance and diversity of amphibian and benthic macroinvertebrates. Variation in habitat physical and chemical conditions, and amphibian and benthic macroinvertebrate diversity and abundance were assessed in the Themi River of Arusha municipality. These physical, chemical and biological conditions were assessed at forty sampling stations...

  12. 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…

  13. Sex determination in amphibians.

    Science.gov (United States)

    Nakamura, Masahisa

    2009-05-01

    The heterogametic sex is male in all mammals, whereas it is female in almost all birds. By contrast, there are two heterogametic types (XX/XY and ZZ/ZW) for genetic sex determination in amphibians. Though the original heterogametic sex was female in amphibians, the two heterogametic types were probably interchangeable, suggesting that sex chromosomes evolved several times in this lineage. Indeed, the frog Rana rugosa has the XX/XY and ZZ/ZW sex-determining systems within a single species, depending on the local population in Japan. The XY and ZW geographic forms with differentiated sex chromosomes probably have a common origin as undifferentiated sex chromosomes resulted from the hybridization between the primary populations of West Japan and Kanto forms. It is clear that the sex chromosomes are still undergoing evolution in this species group. Regardless of the presence of a sex-determining gene in amphibians, the gonadal sex of some species can be changed by sex steroids. Namely, sex steroids can induce the sex reversal, with estrogens inducing the male-to-female sex reversal, whereas androgens have the opposite effect. In R. rugosa, gonadal activity of CYP19 (P450 aromatase) is correlated with the feminization of gonads. Of particular interest is that high levels of CYP19 expression are observed in indifferent gonads at time before sex determination. Increases in the expression of CYP19 in female gonads and CYP17 (P450 17alpha-hydroxylase/C17-20 lyase) in male gonads suggest that the former plays an important role in phenotypic female determination, whereas the latter is needed for male determination. Thus, steroids could be the key factor for sex determination in R. rugosa. In addition to the role of sex steroids in gonadal sex determination in this species, Foxl2 and Sox3 are capable of promoting CYP19 expression. Since both the genes are autosomal, another factor up-regulating CYP19 expression must be recruited. The factor, which may be located on the X or W

  14. Multiple stressor effects in relation to declining amphibian populations

    Science.gov (United States)

    2003-01-01

    This book represents the work of several authors who participated in the symposium entitled 'Multiple Stressor Effects in Relation to Declining Amphibian Populations' convened 16-17 April, 2002, in Pittsburgh, Pennsylvania. Declines of amphibian populations of varying severity have been observed for many years, and in the last 8 to 10 years considerable progress has been made in documenting the status and distribution of a range of amphibian species. Habitat alteration and destruction are likely linked to many amphibian declines, but a variety of other factors, both anthropogenic and natural, have been observed or proposed to have caused declines or extinctions of amphibian populations. Unfortunately, determining the environmental causes for the decline of many species has proven difficult. The goals of this symposium were three-fold. First, highlight ASTM's historic role in providing a forum for the standardization of amphibian toxicity test methods and the characterization of adverse effects potentially associated with chemical stressors. Second, demonstrate through case studies the current state of technical 'tools' available to biologists, ecologists, environmental scientists and natural resource professionals for assessing amphibian populations exposed to various environmental stressors. And third, characterize a process that brings a range of interdisciplinary technical and management tools to the tasks of causal analysis, especially as those relate to a multiple stressor risk assessment 'mind-set.' As part of the symposium, scientists and resource management professionals from diverse fields including ecotoxicology and chemistry, ecology and field biology, conservation biology, and natural resource management and policy contributed oral presentations and posters that addressed topics related to declining amphibian populations and the role that various stressors have in those losses. The papers contained in this publication reflect the commitment of ASTM

  15. DNA barcoding amphibians and reptiles.

    Science.gov (United States)

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

    2012-01-01

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

  16. Amazonian indigenous settlement and local development in Pastaza, Ecuador

    Directory of Open Access Journals (Sweden)

    Ruth I. Arias-Gutiérrez

    2016-07-01

    Full Text Available In six Amazonian indigenous communities that call to their selves as membership of nación Kichwa, located in Pastaza province, in Ecuador, it is analyzed the process of inhabitation, population characteristics, how much the territory is enough for food requirements for the indigenous families, and their use of land, to determine important factors to improve strategies for local sustainable development. It is considered important because Ecuador has constitutional protection for plural ethnicity and it is looking for improving a new productivity matrix that let down extraction and contamination and raise another matrix based on knowledge and richness from natural renewable resources. Survey used statistics information, qualitative analysis around reality in process, participant research, documentary analysis, oral history and surveys to leadership and family`s chiefs. Results confirm that communities hold standing their identity and knowledge systems of the Amazonian environment, whose conservation they need. Those are factors to be included in local development strategies that let people become safe from effects of extractives activities that are dangerous for culture and environment, in the geographic and biological diversity of the high Ecuadorian Amazonia.

  17. Global Amphibian Extinction Risk Assessment for the Panzootic Chytrid Fungus

    Directory of Open Access Journals (Sweden)

    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.

  18. 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.

  19. Biodiversity of trematodes associated with amphibians from a variety of habitats in Corrientes Province, Argentina.

    Science.gov (United States)

    Hamann, M I; Kehr, A I; González, C E

    2013-09-01

    The main goals of this study were to compare the richness of parasitic trematodes in amphibians with diverse habits (terrestrial, fossorial, semi-aquatic and arboreal), and to evaluate whether the composition of the trematode community is determined by ecological relationships. Specimens were collected between April 2001 and December 2006 from a common area (30 ha) in Corrientes Province, Argentina. Trematodes of amphibians in this area comprised a total of 19 species, and were dominated by common species. Larval trematodes presented highest species richness, with the metacercaria of Bursotrema tetracotyloides being dominant in the majority (7/9, 78%) of the parasite communities. Adults of the trematode Catadiscus inopinatus were dominant in the majority (6/9, 67%) of amphibians. The amphibians Leptodactylus latinasus, Leptodactylus bufonius and Scinax nasicus presented a high diversity of trematodes, whereas Leptodactylus chaquensis had the lowest diversity even though it presented with the highest species richness. The patterns of similarity among amphibian species showed groups linking with their habitats. Leptodactilid amphibians, with a generalist diet and an active foraging strategy showed highest infection rates with adult trematodes. The mean richness of trematode species related to host's habitat preferences was higher in semi-aquatic amphibians. Results suggest that semi-aquatic amphibians, present in both aquatic and terrestrial environments, present a greater diversity of parasites as they have a higher rate of exposure to a wider range of prey species and, hence, to diverse infective states. The trematode composition is related to the diets and mobility of the host, and habitat.

  20. Mitigating amphibian chytridiomycosis in nature

    Science.gov (United States)

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

    2016-01-01

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

  1. Resilience of Amazonian landscapes to agricultural intensification

    NARCIS (Netherlands)

    Jakovac, C.C.

    2015-01-01

    ISBN: 978-94-6257-443-4 Author: Catarina C. Jakovac Title: Resilience of Amazonian landscapes to agricultural intensification Swidden cultivation is the traditional agricultural system in riverine Amazonia, which supports local livelihoods and trans

  2. 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...

  3. 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

  4. Spatial Biodiversity Patterns of Madagascar's Amphibians and Reptiles.

    Directory of Open Access Journals (Sweden)

    Jason L Brown

    Full Text Available 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

  5. Nomimoscolex touzeti n. sp. (Cestoda, a parasite of ceratophrys cornuta (L.: first record of a monticellidae in an amphibian host

    Directory of Open Access Journals (Sweden)

    Alain de Chambrier

    1992-01-01

    Full Text Available Nomimoscolex touzeti n. sp. is described from one Ceratophrys cornuta (L. caught in Amazonian Ecuador. Its taxonomic relationships to the others species are discussed. This new species is characterized by a cortical position of vitellaria; by the presence in the uteroduct of conglomerates of 20-40 eggs; by a weak ovary width/proglottis width ratio; by ventral excretory canals anastomosed; by a powerful vaginal sphincter and by a long cirrus. N. touzeti is the first record of Monticellidae in an amphibian host.

  6. Understanding Amphibian Declines Through Geographic Approaches

    Science.gov (United States)

    Gallant, Alisa

    2006-01-01

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

  7. 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...

  8. BIOTIC FACTORS IN AMPHIBIAN POPULATION DECLINES

    Science.gov (United States)

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

  9. Biogeography and evolution of Amazonian triatomines (Heteroptera: Reduviidae: implications for Chagas disease surveillance in humid forest ecoregions

    Directory of Open Access Journals (Sweden)

    Fernando Abad-Franch

    2007-10-01

    Full Text Available An ecological-evolutionary classification of Amazonian triatomines is proposed based on a revision of their main contemporary biogeographical patterns. Truly Amazonian triatomines include the Rhodniini, the Cavernicolini, and perhaps Eratyrus and some Bolboderini. The tribe Rhodniini comprises two major lineages (pictipes and robustus. The former gave rise to trans-Andean (pallescens and Amazonian (pictipes species groups, while the latter diversified within Amazonia (robustus group and radiated to neighbouring ecoregions (Orinoco, Cerrado-Caatinga-Chaco, and Atlantic Forest. Three widely distributed Panstrongylus species probably occupied Amazonia secondarily, while a few Triatoma species include Amazonian populations that occur only in the fringes of the region. T. maculata probably represents a vicariant subset isolated from its parental lineage in the Caatinga-Cerrado system when moist forests closed a dry trans-Amazonian corridor. These diverse Amazonian triatomines display different degrees of synanthropism, defining a behavioural gradient from household invasion by adult triatomines to the stable colonisation of artificial structures. Anthropogenic ecological disturbance (driven by deforestation is probably crucial in the onset of the process, but the fact that only a small fraction of species effectively colonises artificial environments suggests a role for evolution at the end of the gradient. Domestic infestation foci are restricted to drier subregions within Amazonia; thus, populations adapted to extremely humid rainforest microclimates may have limited chances of successfully colonising the slightly drier artificial microenvironments. These observations suggest several research avenues, from the use of climate data to map risk areas to the assessment of the synanthropic potential of individual vector species.

  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. 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

  12. Sleep in an Amazonian manatee, Trichechus inunguis.

    Science.gov (United States)

    Mukhametov, L M; Lyamin, O I; Chetyrbok, I S; Vassilyev, A A; Diaz, R P

    1992-04-15

    For the first time, sleep was studied in a representative of the order of Sirenia. Slow wave sleep occupied 27%, and paradoxical sleep 1% of the total recording time in the Amazonian manatee. Trichechus inunguis. The circadian rhythmicity of sleep was pronounced. During the sleep period, the manatee woke up for a short time for each respiratory act. Interhemispheric asynchrony of the electrocortical slow wave activity was found. PMID:1582500

  13. Litter mercury deposition in the Amazonian rainforest.

    Science.gov (United States)

    Fostier, Anne Hélène; Melendez-Perez, José Javier; Richter, Larissa

    2015-11-01

    The objective of this work was to assess the flux of atmospheric mercury transferred to the soil of the Amazonian rainforest by litterfall. Calculations were based on a large survey of published and unpublished data on litterfall and Hg concentrations in litterfall samples from the Amazonian region. Litterfall based on 65 sites located in the Amazon rainforest averaged 8.15 ± 2.25 Mg ha(-1) y(-1). Average Hg concentrations were calculated from nine datasets for fresh tree leaves and ten datasets for litter, and a median concentration of 60.5 ng Hg g(-1) was considered for Hg deposition in litterfall, which averaged 49 ± 14 μg m(-2) yr(-1). This value was used to estimate that in the Amazonian rainforest, litterfall would be responsible for the annual removing of 268 ± 77 Mg of Hg, approximately 8% of the total atmospheric Hg deposition to land. The impact of the Amazon deforestation on the Hg biogeochemical cycle is also discussed. PMID:26312742

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

    Science.gov (United States)

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

    2012-10-01

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

  15. 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.

  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. Ecopathology of ranaviruses infecting amphibians.

    Science.gov (United States)

    Miller, Debra; Gray, Matthew; Storfer, Andrew

    2011-11-01

    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.

  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. Diversity and Fauna Analysis of Amphibians in Wuzhishan Reserve%五指山保护区两栖动物多样性调查及区系特征

    Institute of Scientific and Technical Information of China (English)

    曲江勇

    2012-01-01

    2010年6月和2011年7月对海南省五指山地区两栖动物资源进行了调查,结果表明,该区内有两栖动物23种,隶属于1目5科11属,全部为东洋界种类,其中华南区有13种,华中-华南区有10种,海南特有种有7种,具有典型的华南区系成分和热带山地林灌动物群特征。国家Ⅱ级保护动物1种(虎纹蛙)。优势种有黑眶蟾蜍、沼蛙、虎纹蛙、滇南臭蛙、云南臭蛙、细刺蛙、小湍蛙。%The amphibian resources in Wuzhishan Reserve were investigated from the years 2010 to 2012. The results show that 23 species of amphibians are recorded, belonging to 1 order 5 families and 13 genera. All species belong to Oriental element, of which 13 species occupy the dominant position in Southern China and 10 species in Central and Southern China. 7 endemic species of Hainan Island distribute in Wuzhishan Reserve, which are typi- cal Southern China species with tropical and upland forest fauna characteristics. Hoplobatrachus rugulosa is state major protected wildlife grade Ⅱ. The species dominant in abundance are Duttaphrynus melanostictus, Hylarana guentheri, Hoplobatrachus rugulosa, Rana tiannanensis, R. andersonii, R. spinulosa, Amolops torrentis.

  1. Mosquitoes of eastern Amazonian Ecuador: biodiversity, bionomics and barcodes

    Directory of Open Access Journals (Sweden)

    Yvonne-Marie Linton

    2013-01-01

    Full Text Available Two snapshot surveys to establish the diversity and ecological preferences of mosquitoes (Diptera: Culicidae in the terra firme primary rain forest surrounding the Tiputini Biodiversity Station in the UNESCO Yasuní Biosphere Reserve of eastern Amazonian Ecuador were carried out in November 1998 and May 1999. The mosquito fauna of this region is poorly known; the focus of this study was to obtain high quality link-reared specimens that could be used to unequivocally confirm species level diversity through integrated systematic study of all life stages and DNA sequences. A total of 2,284 specimens were preserved; 1,671 specimens were link-reared with associated immature exuviae, all but 108 of which are slide mounted. This study identified 68 unique taxa belonging to 17 genera and 27 subgenera. Of these, 12 are new to science and 37 comprise new country records. DNA barcodes [658-bp of the mtDNA cytochrome c oxidase ( COI I gene] are presented for 58 individuals representing 20 species and nine genera. DNA barcoding proved useful in uncovering and confirming new species and we advocate an integrated systematics approach to biodiversity studies in future. Associated bionomics of all species collected are discussed. An updated systematic checklist of the mosquitoes of Ecuador (n = 179 is presented for the first time in 60 years.

  2. Amphibian malformations and inbreeding

    OpenAIRE

    Williams, Rod N.; Bos, David H; Gopurenko, David; DeWoody, J. Andrew

    2008-01-01

    Inbreeding may lead to morphological malformations in a wide variety of taxa. We used genetic markers to evaluate whether malformed urodeles were more inbred and/or had less genetic diversity than normal salamanders. We captured 687 adult and 1259 larval tiger salamanders (Ambystoma tigrinum tigrinum), assessed each individual for gross malformations, and surveyed genetic variation among malformed and normal individuals using both cytoplasmic and nuclear markers. The most common malformations...

  3. Amphibians as models for studying environmental change.

    Science.gov (United States)

    Hopkins, William A

    2007-01-01

    The use of amphibians as models in ecological research has a rich history. From an early foundation in studies of amphibian natural history sprang generations of scientists who used amphibians as models to address fundamental questions in population and community ecology. More recently, in the wake of an environment that human disturbances rapidly altered, ecologists have adopted amphibians as models for studying applied ecological issues such as habitat loss, pollution, disease, and global climate change. Some of the characteristics of amphibians that make them useful models for studying these environmental problems are highlighted, including their trophic importance, environmental sensitivity, research tractability, and impending extinction. The article provides specific examples from the recent literature to illustrate how studies on amphibians have been instrumental in guiding scientific thought on a broad scale. Included are examples of how amphibian research has transformed scientific disciplines, generated new theories about global health, called into question widely accepted scientific paradigms, and raised awareness in the general public that our daily actions may have widespread repercussions. In addition, studies on amphibian declines have provided insight into the complexity in which multiple independent factors may interact with one another to produce catastrophic and sometimes unpredictable effects. Because of the complexity of these problems, amphibian ecologists have been among the strongest advocates for interdisciplinary research. Future studies of amphibians will be important not only for their conservation but also for the conservation of other species, critical habitats, and entire ecosystems.

  4. Conservation genetics and genomics of amphibians and reptiles.

    Science.gov (United States)

    Shaffer, H Bradley; Gidiş, Müge; McCartney-Melstad, Evan; Neal, Kevin M; Oyamaguchi, Hilton M; Tellez, Marisa; Toffelmier, Erin M

    2015-01-01

    Amphibians and reptiles as a group are often secretive, reach their greatest diversity often in remote tropical regions, and contain some of the most endangered groups of organisms on earth. Particularly in the past decade, genetics and genomics have been instrumental in the conservation biology of these cryptic vertebrates, enabling work ranging from the identification of populations subject to trade and exploitation, to the identification of cryptic lineages harboring critical genetic variation, to the analysis of genes controlling key life history traits. In this review, we highlight some of the most important ways that genetic analyses have brought new insights to the conservation of amphibians and reptiles. Although genomics has only recently emerged as part of this conservation tool kit, several large-scale data sources, including full genomes, expressed sequence tags, and transcriptomes, are providing new opportunities to identify key genes, quantify landscape effects, and manage captive breeding stocks of at-risk species.

  5. 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

  6. Placentation in the Amazonian manatee (Trichechus inunguis)

    DEFF Research Database (Denmark)

    Carter, A M; Miglino, M A; Ambrosio, C E;

    2008-01-01

    Evidence from several sources supports a close phylogenetic relationship between elephants and sirenians. To explore whether this was reflected in similar placentation, we examined eight delivered placentae from the Amazonian manatee using light microscopy and immunohistochemistry. In addition......, the fetal placental circulation was described by scanning electron microscopy of vessel casts. The manatee placenta was zonary and endotheliochorial, like that of the elephant. The interhaemal barrier comprised maternal endothelium, cytotrophoblasts and fetal endothelium. We found columnar trophoblast...... detail, but maternal capillaries ran rather straight and roughly parallel to the fetal ones. Overall, there is a close resemblance in placentation between the manatee and the elephant....

  7. Endoparasites in some Swedish Amphibians

    DEFF Research Database (Denmark)

    Cedhagen, Tomas

    1988-01-01

    A study was made of the endoparasites in specimens of Rana arvalis and R. temporaria collected on two occasions from a locality of southern Sweden. Some frogs were investigated directly after capture while other frogs were kept hibernating and the composition of the parasites as well as the behav...... not previously been reported from Sweden. The late Prof. O. Nybelin's unpublished records of parasites found in Swedish amphibians are also given....

  8. Mine Spoil Prairies Expand Critical Habitat for Endangered and Threatened Amphibian and Reptile Species

    Directory of Open Access Journals (Sweden)

    Nathan J. Engbrecht

    2009-11-01

    Full Text Available 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.

  9. Survey for the amphibian chytrid Batrachochytrium dendrobatidis in Hong Kong in native amphibians and in the international amphibian trade.

    Science.gov (United States)

    Rowley, Jodi J L; Chan, Simon Kin Fung; Tang, Wing Sze; Speare, Richard; Skerratt, Lee F; Alford, Ross A; Cheung, Ka Shing; Ho, Ching Yee; Campbell, Ruth

    2007-12-13

    Chytridiomycosis, caused by the pathogen Batrachochytrium dendrobatidis, is responsible for many amphibian declines and has been identified in wild amphibian populations on all continents where they exist, except for Asia. In order to assess whether B. dendrobatidis is present on the native amphibians of Hong Kong, we sampled wild populations of Amolops hongkongensis, Paa exilispinosa, P. spinosa and Rana chloronota during 2005-2006. Amphibians infected with B. dendrobatidis have been found in the international trade, so we also examined the extent and nature of the amphibian trade in Hong Kong during 2005-2006, and assessed whether B. dendrobatidis was present in imported amphibians. All 274 individuals of 4 native amphibian species sampled tested negative for B. dendrobatidis, giving an upper 95% confidence limit for prevalence of 1.3%. Approximately 4.3 million amphibians of 45 species from 11 countries were imported into Hong Kong via air over 12 mo; we did not detect B. dendrobatidis on any of 137 imported amphibians sampled. As B. dendrobatidis generally occurs at greater than 5% prevalence in infected populations during favorable environmental conditions, native amphibians in Hong Kong appear free of B. dendrobatidis, and may be at severe risk of impact if it is introduced. Until it is established that the pathogen is present in Hong Kong, management strategies should focus on preventing it from being imported and decreasing the risk of it escaping into the wild amphibian populations if imported. Further research is needed to determine the status of B. dendrobatidis in Hong Kong with greater certainty.

  10. 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....

  11. Endemic and introduced haplotypes of Batrachochytrium dendrobatidis in Japanese amphibians: sink or source?

    Science.gov (United States)

    Fisher, Matthew C

    2009-12-01

    The global emergence of the amphibian chytrid pathogen Batrachochytrium dendrobatidis (Bd) is one of the most compelling, and troubling, examples of a panzootic. Only discovered in 1998, Bd is now recognized as a proximate driver of global declines in amphibian diversity and is now widely acknowledged as a key threatening process for this ancient class of vertebrates. Moreover, Bd has become a member of a small group of highly virulent multihost pathogens that are known to have had effects on entire vertebrate communities and the ecosystem-level effects of Bd-driven amphibian declines are starting to emerge as a consequence of regional decreases in amphibian diversity. Despite the speed at which this species of aquatic chytrid has become a focus of research efforts, major questions still exist about where Bd originated, how it spreads, where it occurs and what are Bd's effects on populations and species inhabiting different regions and biomes. In this issue, Goka et al. (2009) make an important contribution by publishing the first nationwide surveillance for Bd in Asia. Although previous data had suggested that amphibians in Asia are largely uninfected by Bd, these surveys were limited in their extent and few firm conclusions could be drawn about the true extent of infection. Goka et al. herein describe a systematic surveillance of Japan for both native and exotic species in the wild, as well as amphibians housed in captivity, using a Bd-specific nested PCR reaction on a sample of over 2600 amphibians. Their results show that Bd is widely prevalent in native species across Japan in at least three of the islands that make up the archipelago, proving for the first time that Asia harbours Bd.

  12. Neuroendocrine-immune system interactions in amphibians: implications for understanding global amphibian declines.

    Science.gov (United States)

    Rollins-Smith, L A

    2001-01-01

    Amphibians are ancient creatures valued by biologists and naturalists around the world. They share with all other vertebrates a complex neuroendocrine system that enables them to flourish in a variety of aquatic and semiaquatic environments. Studies from a number of laboratories have demonstrated that the immune system of amphibian species is nearly as complex as that of mammals. Yet for reasons that are not well understood, amphibian species are facing greater survival challenges than in the recent past. This article will review our current understanding of the neuroendocrine immune system interactions in amphibians and address the question of whether environmental stressors may contribute to immunosuppression and amphibian declines.

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

    Science.gov (United States)

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

    2014-09-01

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

  14. Fungal Community Assembly in the Amazonian Dark Earth.

    Science.gov (United States)

    Lucheta, Adriano Reis; Cannavan, Fabiana de Souza; Roesch, Luiz Fernando Wurdig; Tsai, Siu Mui; Kuramae, Eiko Eurya

    2016-05-01

    Here, we compare the fungal community composition and diversity in Amazonian Dark Earth (ADE) and the respective non-anthropogenic origin adjacent (ADJ) soils from four different sites in Brazilian Central Amazon using pyrosequencing of 18S ribosomal RNA (rRNA) gene. Fungal community composition in ADE soils were more similar to each other than their ADJ soils, except for only one site. Phosphorus and aluminum saturation were the main soil chemical factors contributing to ADE and ADJ fungal community dissimilarities. Differences in fungal richness were not observed between ADE and ADJ soil pairs regarding to the most sites. In general, the most dominant subphyla present in the soils were Pezizomycotina, Agaricomycotina, and Mortierellomycotina. The most abundant operational taxonomic units (OTUs) in ADE showed similarities with the entomopathogenic fungus Cordyceps confragosa and the saprobes Fomitopsis pinicola, Acremonium vitellinum, and Mortierellaceae sp., whereas OTUs similar to Aspergillus niger, Lithothelium septemseptatum, Heliocephala gracillis, and Pestalosphaeria sp. were more abundant in ADJ soils. Differences in fungal community composition were associated to soil chemical factors in ADE (P, Ca, Zn, Mg, organic matter, sum of bases, and base saturation) and ADJ (Al, potential acidity, Al saturation, B, and Fe) soils. These results contribute to a deeper view of the fungi communities in ADE and open new perspectives for entomopathogenic fungi studies. PMID:26585119

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

    Science.gov (United States)

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

    2011-11-01

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

  16. The complexity of amphibian population declines: understanding the role of cofactors in driving amphibian losses.

    Science.gov (United States)

    Blaustein, Andrew R; Han, Barbara A; Relyea, Rick A; Johnson, Pieter T J; Buck, Julia C; Gervasi, Stephanie S; Kats, Lee B

    2011-03-01

    Population losses and extinctions of species are occurring at unprecedented rates, as exemplified by declines and extinctions of amphibians worldwide. However, studies of amphibian population declines generally do not address the complexity of the phenomenon or its implications for ecological communities, focusing instead on single factors affecting particular amphibian species. We argue that the causes for amphibian population declines are complex; may differ among species, populations, and life stages within a population; and are context dependent with multiple stressors interacting to drive declines. Because amphibians are key components of communities, we emphasize the importance of investigating amphibian declines at the community level. Selection pressures over evolutionary time have molded amphibian life history characteristics, such that they may remain static even in the face of strong, recent human-induced selection pressures.

  17. New Brazilian Cerambycidae from the Amazonian region (Coleoptera)

    Science.gov (United States)

    Santos-Silva, Antonio; Galileo, Maria Helena M.

    2016-01-01

    Abstract Three new species of Cerambycidae are described from the Brazilian Amazonian region: Psapharochrus bezarki (Lamiinae, Acanthoderini); Xenofrea ayri (Lamiinae, Xenofreini); and Mecometopus wappesi (Cerambycinae, Clytini). Mecometopus wappesi is added to a previous key. PMID:27551200

  18. Isozyme characterization of Capsicum accessions from the Amazonian Colombian collection

    OpenAIRE

    Lorena Quintero Barrera; Marisol Cudris García; Martha Cecilia Giraldo; Luz Marina Melgarejo

    2007-01-01

    Two hundred and sixty-one accessions of the genus Capsicum were obtained from the Colombian Amazonian germplasm bank at Amazonian Institute of Scientific Research (Sinchi) and were evaluated with five polymorphic enzymatic systems, including esterase (EST), peroxidase (PRX), 6-phosphogluconate dehydrogenase (6-PGDH), aspartate amino transferase (GOT), and malic enzyme (ME). Using a cluster analysis (UPGMA) the genetic variability of these accessions were characterized. Grouping of the species...

  19. Effect of biogeographic history on population vulnerability in European amphibians.

    Science.gov (United States)

    Dufresnes, Christophe; Perrin, Nicolas

    2015-08-01

    The genetic diversity of populations, which contributes greatly to their adaptive potential, is negatively affected by anthropogenic habitat fragmentation and destruction. However, continental-scale losses of genetic diversity also resulted from the population expansions that followed the end of the last glaciation, an element that is rarely considered in a conservation context. We addressed this issue in a meta-analysis in which we compared the spatial patterns of vulnerability of 18 widespread European amphibians in light of phylogeographic histories (glacial refugia and postglacial routes) and anthropogenic disturbances. Conservation statuses significantly worsened with distances from refugia, particularly in the context of industrial agriculture; human population density also had a negative effect. These findings suggest that features associated with the loss of genetic diversity in post-glacial amphibian populations (such as enhanced fixation load or depressed adaptive potential) may increase their susceptibility to current threats (e.g., habitat fragmentation and pesticide use). We propose that the phylogeographic status of populations (i.e., refugial vs. post-glacial) should be considered in conservation assessments for regional and national red lists.

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

    Science.gov (United States)

    Fasola, E; Ribeiro, R; Lopes, I

    2015-09-01

    The loss of genetic diversity, due to exposure to chemical contamination (genetic erosion), is a major threat to population viability. Genetic erosion is the loss of genetic variation: the loss of alleles determining the value of a specific trait or set of traits. Almost a third of the known amphibian species is considered to be endangered and a decrease of genetic variability can push them to the verge of extinction. This review indicates that loss of genetic variation due to chemical contamination has effects on: 1) fitness, 2) environmental plasticity, 3) co-tolerance mechanisms, 4) trade-off mechanisms, and 5) tolerance to pathogens in amphibian populations.

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

    Science.gov (United States)

    Kolby, Jonathan E; Smith, Kristine M; Berger, Lee; Karesh, William B; Preston, Asa; Pessier, Allan P; Skerratt, Lee F

    2014-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Sperm storage in caecilian amphibians

    Directory of Open Access Journals (Sweden)

    Kuehnel Susanne

    2012-06-01

    Full Text Available Abstract Background Female sperm storage has evolved independently multiple times among vertebrates to control reproduction in response to the environment. In internally fertilising amphibians, female salamanders store sperm in cloacal spermathecae, whereas among anurans sperm storage in oviducts is known only in tailed frogs. Facilitated through extensive field sampling following historical observations we tested for sperm storing structures in the female urogenital tract of fossorial, tropical caecilian amphibians. Findings In the oviparous Ichthyophis cf. kohtaoensis, aggregated sperm were present in a distinct region of the posterior oviduct but not in the cloaca in six out of seven vitellogenic females prior to oviposition. Spermatozoa were found most abundantly between the mucosal folds. In relation to the reproductive status decreased amounts of sperm were present in gravid females compared to pre-ovulatory females. Sperm were absent in females past oviposition. Conclusions Our findings indicate short-term oviductal sperm storage in the oviparous Ichthyophis cf. kohtaoensis. We assume that in female caecilians exhibiting high levels of parental investment sperm storage has evolved in order to optimally coordinate reproductive events and to increase fitness.

  4. Ossification sequence heterochrony among amphibians.

    Science.gov (United States)

    Harrington, Sean M; Harrison, Luke B; Sheil, Christopher A

    2013-01-01

    Heterochrony is an important mechanism in the evolution of amphibians. Although studies have centered on the relationship between size and shape and the rates of development, ossification sequence heterochrony also may have been important. Rigorous, phylogenetic methods for assessing sequence heterochrony are relatively new, and a comprehensive study of the relative timing of ossification of skeletal elements has not been used to identify instances of sequence heterochrony across Amphibia. In this study, a new version of the program Parsimov-based genetic inference (PGi) was used to identify shifts in ossification sequences across all extant orders of amphibians, for all major structural units of the skeleton. PGi identified a number of heterochronic sequence shifts in all analyses, the most interesting of which seem to be tied to differences in metamorphic patterns among major clades. Early ossification of the vomer, premaxilla, and dentary is retained by Apateon caducus and members of Gymnophiona and Urodela, which lack the strongly biphasic development seen in anurans. In contrast, bones associated with the jaws and face were identified as shifting late in the ancestor of Anura. The bones that do not shift late, and thereby occupy the earliest positions in the anuran cranial sequence, are those in regions of the skull that undergo the least restructuring throughout anuran metamorphosis. Additionally, within Anura, bones of the hind limb and pelvic girdle were also identified as shifting early in the sequence of ossification, which may be a result of functional constraints imposed by the drastic metamorphosis of most anurans.

  5. 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

  6. 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

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

    Science.gov (United States)

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

    2009-01-01

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

  8. Amphibian declines in the twenty-first century: why we need assisted reproductive technologies.

    Science.gov (United States)

    Clulow, John; Trudeau, Vance L; Kouba, Andrew J

    2014-01-01

    Each amphibian species is evolutionarily distinct, having developed highly specialized and diverse reproductive strategies in both terrestrial and aquatic environments. These unique reproductive patterns and mechanisms, key to species propagation, have only been explored in a limited number of laboratory models. Although the development of applied reproductive technologies for amphibians has proven useful for a few threatened species, the real benefit of this technology has been new insights into the reproductive adaptations, behavior, endocrinology, and physiological mechanisms that have evolved over millions of years. As the basic fundamental database on amphibian reproductive physiology has grown, so has the applied benefit for species conservation. In particular, technologies such as non-invasive fecal and urinary hormone assays, hormone treatments for induced breeding or gamete collection, in vitro fertilization, and the ability to establish genome resource banks have all played important roles in monitoring or managing small populations of captive species. Amphibians have the ability to produce a large excess of germplasm (up to 10,000 ovulated eggs in a single reproductive event) that if not collected and preserved, would represent a wasted valuable resource. We discuss the current state of knowledge in assisted reproductive technologies for amphibians and why their extinction crisis means these available tools can no longer be implemented as small-scale, last-ditch efforts. The reproductive technologies must be established early as a key component of large-scale species recovery.

  9. 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.

  10. Chytridiomycosis: a global threat to amphibians.

    Science.gov (United States)

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

    2013-12-01

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

  11. Origin and functional diversification of an amphibian defense peptide arsenal.

    Directory of Open Access Journals (Sweden)

    Kim Roelants

    Full Text Available The skin secretion of many amphibians contains an arsenal of bioactive molecules, including hormone-like peptides (HLPs acting as defense toxins against predators, and antimicrobial peptides (AMPs providing protection against infectious microorganisms. Several amphibian taxa seem to have independently acquired the genes to produce skin-secreted peptide arsenals, but it remains unknown how these originated from a non-defensive ancestral gene and evolved diverse defense functions against predators and pathogens. We conducted transcriptome, genome, peptidome and phylogenetic analyses to chart the full gene repertoire underlying the defense peptide arsenal of the frog Silurana tropicalis and reconstruct its evolutionary history. Our study uncovers a cluster of 13 transcriptionally active genes, together encoding up to 19 peptides, including diverse HLP homologues and AMPs. This gene cluster arose from a duplicated gastrointestinal hormone gene that attained a HLP-like defense function after major remodeling of its promoter region. Instead, new defense functions, including antimicrobial activity, arose by mutation of the precursor proteins, resulting in the proteolytic processing of secondary peptides alongside the original ones. Although gene duplication did not trigger functional innovation, it may have subsequently facilitated the convergent loss of the original function in multiple gene lineages (subfunctionalization, completing their transformation from HLP gene to AMP gene. The processing of multiple peptides from a single precursor entails a mechanism through which peptide-encoding genes may establish new functions without the need for gene duplication to avoid adaptive conflicts with older ones.

  12. 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

  13. Fire patterns in the Amazonian biome

    Science.gov (United States)

    Aragao, Luiz E. O. C.; Shimabukuro, Yosio E.; Lima, Andre; Anderson, Liana O.; Barbier, Nicolas; Saatchi, Sassan

    2010-05-01

    This paper aims to provide an overview of our recent findings on the interplay between climate and land use dynamics in defining fire patterns in Amazonia. Understanding these relationships is currently a fundamental concern for assessing the vulnerability of Amazonia to climate change and its potential for mitigating current increases in atmospheric greenhouse gases. Reducing carbon emissions from tropical deforestation and forest degradation (REDD), for instance, could contribute to a cumulative emission reduction of 13-50 billion tons of carbon (GtC) by 2100. In Amazonia, though, forest fires can release similar quantities of carbon to the atmosphere (~0.2 GtC yr-1) as deforestation alone. Therefore, to achieve carbon savings through REDD mechanism there is an urgent need of understanding and subsequently restraining related Amazonian fire drivers. In this study, we analyze satellite-derived monthly and annual time-series of fires, rainfall and deforestation in Amazonia to: (1) quantify the seasonal patterns and relationships between these variables; (2) quantify fire and rainfall anomalies to evaluate the impact of recent drought on fire patterns; (3) quantify recent trends in fire and deforestation to understand how land use affects fire patterns in Amazonia. Our results demonstrate a marked seasonality of fires. The majority of fires occurs along the Arc of Deforestation, the expanding agricultural frontier in southern and eastern Amazonia, indicating humans are the major ignition sources determining fire seasonality, spatial distribution and long-term patterns. There is a marked seasonality of fires, which is highly correlated (pslash-and-burn of Amazonian vegetation for implementation of pastures and agricultural fields. The cumulative number of hot pixels is exponentially related to the monthly rainfall, which ultimately defines where and when fire can potentially strike. During the 2005 Amazonian drought, the number of hot pixels increased 33% in relation

  14. A meta-analysis of the effects of ultraviolet B radiation and its synergistic interactions with pH, contaminants, and disease on amphibian survival.

    Science.gov (United States)

    Bancroft, Betsy A; Baker, Nick J; Blaustein, Andrew R

    2008-08-01

    Human alterations to natural systems have resulted in a loss of biological diversity around the world. Amphibian population losses have been more severe than those of birds and mammals. Amphibian population declines are likely due to many factors including habitat loss, disease, contaminants, introduced species and ultraviolet-B (UVB) radiation. The effect of UVB, however, varies widely among species and can vary within populations of the same species or at different life-history stages. This variation has often led to opposing conclusions about how UVB affects amphibians. We used meta-analysis techniques to explore the overall effects of UVB radiation on survival in amphibians. We also used recently developed factorial meta-analytic techniques to quantify potential interactions between UVB radiation and other stressors on amphibians. Ultraviolet-B radiation reduced survival of amphibians by 1.9-fold compared with shielded controls. Larvae were more susceptible to damage from UVB radiation compared with embryos, and salamanders were more susceptible compared with frogs and toads. Furthermore, UVB radiation interacted synergistically with other environmental stressors and resulted in greater than additive effects on survival when 2 stressors were present. Our results suggest that UVB radiation is an important stressor in amphibians, particularly in light of potential synergisms between UVB and other stressors in amphibian habitats.

  15. 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...

  16. 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.

  17. The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa

    Science.gov (United States)

    ter Steege, Hans; Vaessen, Rens W.; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C. A.; Jørgensen, Peter Møller; Salomão, Rafael P.

    2016-01-01

    Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species’ range size is a better predictor of the number of times it has been collected than the species’ estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites. PMID:27406027

  18. The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa

    Science.gov (United States)

    Ter Steege, Hans; Vaessen, Rens W.; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C. A.; Jørgensen, Peter Møller; Salomão, Rafael P.

    2016-07-01

    Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species’ range size is a better predictor of the number of times it has been collected than the species’ estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites.

  19. The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa.

    Science.gov (United States)

    Ter Steege, Hans; Vaessen, Rens W; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C A; Jørgensen, Peter Møller; Salomão, Rafael P

    2016-01-01

    Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species' range size is a better predictor of the number of times it has been collected than the species' estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites. PMID:27406027

  20. Phthalate pollution in an Amazonian rainforest.

    Science.gov (United States)

    Lenoir, Alain; Boulay, Raphaël; Dejean, Alain; Touchard, Axel; Cuvillier-Hot, Virginie

    2016-08-01

    Phthalates are ubiquitous contaminants and endocrine-disrupting chemicals that can become trapped in the cuticles of insects, including ants which were recognized as good bioindicators for such pollution. Because phthalates have been noted in developed countries and because they also have been found in the Arctic, a region isolated from direct anthropogenic influence, we hypothesized that they are widespread. So, we looked for their presence on the cuticle of ants gathered from isolated areas of the Amazonian rainforest and along an anthropogenic gradient of pollution (rainforest vs. road sides vs. cities in French Guiana). Phthalate pollution (mainly di(2-ethylhexyl) phthalate (DEHP)) was higher on ants gathered in cities and along road sides than on those collected in the pristine rainforest, indicating that it follows a human-mediated gradient of disturbance related to the use of plastics and many other products that contain phthalates in urban zones. Their presence varied with the ant species; the cuticle of Solenopsis saevissima traps higher amount of phthalates than that of compared species. However, the presence of phthalates in isolated areas of pristine rainforests suggests that they are associated both with atmospheric particles and in gaseous form and are transported over long distances by wind, resulting in a worldwide diffusion. These findings suggest that there is no such thing as a "pristine" zone. PMID:27372101

  1. An examination of amphibian sensitivity to environmental contaminants: are amphibians poor canaries?

    Science.gov (United States)

    Kerby, Jacob L; Richards-Hrdlicka, Kathryn L; Storfer, Andrew; Skelly, David K

    2010-01-01

    Nearly two decades ago, the global biodiversity crisis was catapulted to the front pages of newspapers with the recognition of worldwide amphibian declines. Amphibians earned their appellation, 'canaries in a coal mine', because of apparent high sensitivity to human-mediated environmental change. The most frequently cited causes for high susceptibility include permeable skin, a dual aquatic-terrestrial life cycle and a relatively rudimentary immune system. While some researchers have questioned the basis for the canary assertion, there has been no systematic evaluation of amphibian sensitivity to environmental challenges relative to other taxa. Here, we apply a database representing thousands of toxicity tests to compare the responses of amphibians relative to that of other taxonomic groups. The use of standardized methods combined with large numbers of identical challenges enables a particularly powerful test of relative effect size. Overall, we found that amphibians only exhibit moderate relative responses to water-borne toxins. Our findings imply that, as far as chemical contaminants are concerned, amphibians are not particularly sensitive and might more aptly be described as 'miners in a coal mine'. To the extent that amphibian declines have been mediated by chemical contaminants, our findings suggest that population losses and extinctions may have already occurred in a variety of taxa much more sensitive than amphibians.

  2. Amazonian malaria: Asymptomatic human reservoirs, diagnostic challenges, environmentally-driven changes in mosquito vector populations, and the mandate for sustainable control strategies

    OpenAIRE

    da Silva-Nunes, Mônica; Moreno, Marta; Jan E Conn; Gamboa, Dionicia; Abeles, Shira; Vinetz, Joseph M.; Ferreira, Marcelo U.

    2011-01-01

    Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite P. vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is place...

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

    Science.gov (United States)

    Mushet, David M.; Neau, Jordan L.

    2014-01-01

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

  4. Amphibian responses to wildfire in the western united states: Emerging patterns from short-term studies

    Science.gov (United States)

    Hossack, B.R.; Pilliod, D.S.

    2011-01-01

    The increased frequency and severity of large wildfires in the western United States is an important ecological and management issue with direct relevance to amphibian conservation. Although the knowledge of fire effects on amphibians in the region is still limited relative to most other vertebrate species, we reviewed the current literature to determine if there are evident patterns that might be informative for conservation or management strategies. Of the seven studies that compared pre- and post-wildfire data on a variety of metrics, ranging from amphibian occupancy to body condition, two reported positive responses and five detected negative responses by at least one species. Another seven studies used a retrospective approach to compare effects of wildfire on populations: two studies reported positive effects, three reported negative effects from wildfire, and two reported no effects. All four studies that included plethodontid salamanders reported negative effects on populations or individuals; these effects were greater in forests where fire had been suppressed and in areas that burned with high severity. Species that breed in streams are also vulnerable to post-wildfire changes in habitat, especially in the Southwest. Wildfire is also important for maintaining suitable habitat for diverse amphibian communities, although those results may not be evident immediately after an area burns. We expect that wildfire will extirpate few healthy amphibian populations, but it is still unclear how populations will respond to wildfire in the context of land management (including pre- and post-fire timber harvest) and fragmentation. Wildfire may also increase the risk of decline or extirpation for small, isolated, or stressed (e.g., from drought or disease) populations. Improved understanding of how these effects vary according to changes in fire frequency and severity are critical to form more effective conservation strategies for amphibians in the western United States.

  5. Countryside biogeography of Neotropical reptiles and amphibians.

    Science.gov (United States)

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

    2014-04-01

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

  6. Amphibians used in research and teaching.

    Science.gov (United States)

    O'Rourke, Dorcas P

    2007-01-01

    Amphibians have long been utilized in scientific research and in education. Historically, investigators have accumulated a wealth of information on the natural history and biology of amphibians, and this body of information is continually expanding as researchers describe new species and study the behaviors of these animals. Amphibians evolved as models for a variety of developmental and physiological processes, largely due to their unique ability to undergo metamorphosis. Scientists have used amphibian embryos to evaluate the effects of toxins, mutagens, and teratogens. Likewise, the animals are invaluable in research due to the ability of some species to regenerate limbs. Certain species of amphibians have short generation times and genetic constructs that make them desirable for transgenic and knockout technology, and there is a current national focus on developing these species for genetic and genomic research. This group of vertebrates is also critically important in the investigation of the inter-relationship of humans and the environment based on their sensitivity to climatic and habitat changes and environmental contamination.

  7. 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...

  8. amphibians and reptiles of luzon island, philippines, Ⅵ:the herpetofauna of the subic bay area

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    we present detailed species accounts for 55 species of amphibians and reptiles (14 species of frogs,24 snakes,16 lizards,one turtle) from 24 localities in the vicinity of subic bay,southern zambales province,luzon island,philippines.although we note numerous species that are conspicuously absent in subic bay (and which we expect will eventually be recorded in the region),our many new records plus a summary of the available historical museum specimen data depict a diverse subset of species diversity known from the southern zambales mountains of southwestern luzon.we compare our data to several other recent herpetofunal surveys from luzon,discuss biogeographic regionalism of this complex island,and report on numerous new natural history observations for many included species.with the absence of any protected areas in the entire province,the amphibians and reptiles of zambales should be a particularly important future conservation priority.

  9. Contributions to the knowledge of amphibians and reptiles from Volta Grande do Xingu, northern Brazil.

    Science.gov (United States)

    Vaz-Silva, W; Oliveira, R M; Gonzaga, A F N; Pinto, K C; Poli, F C; Bilce, T M; Penhacek, M; Wronski, L; Martins, J X; Junqueira, T G; Cesca, L C C; Guimarães, V Y; Pinheiro, R D

    2015-08-01

    The region of Volta Grande do Xingu River, in the state of Pará, presents several kinds of land use ranging from extensive cattle farming to agroforestry, and deforestation. Currently, the Belo Monte Hydroelectric Power Plant affects the region. We present a checklist of amphibians and reptiles of the region and discuss information regarding the spatial distribution of the assemblies based on results of Environmental Programmes conducted in the area. We listed 109 amphibian (Anura, Caudata, and Gymnophiona) and 150 reptile (Squamata, Testudines, and Crocodylia) species. The regional species richness is still considered underestimated, considering the taxonomic uncertainty, complexity and cryptic diversity of various species, as observed in other regions of the Amazon biome. Efforts for scientific collection and studies related to integrative taxonomy are needed to elucidate uncertainties and increase levels of knowledge of the local diversity.

  10. Contributions to the knowledge of amphibians and reptiles from Volta Grande do Xingu, northern Brazil.

    Science.gov (United States)

    Vaz-Silva, W; Oliveira, R M; Gonzaga, A F N; Pinto, K C; Poli, F C; Bilce, T M; Penhacek, M; Wronski, L; Martins, J X; Junqueira, T G; Cesca, L C C; Guimarães, V Y; Pinheiro, R D

    2015-08-01

    The region of Volta Grande do Xingu River, in the state of Pará, presents several kinds of land use ranging from extensive cattle farming to agroforestry, and deforestation. Currently, the Belo Monte Hydroelectric Power Plant affects the region. We present a checklist of amphibians and reptiles of the region and discuss information regarding the spatial distribution of the assemblies based on results of Environmental Programmes conducted in the area. We listed 109 amphibian (Anura, Caudata, and Gymnophiona) and 150 reptile (Squamata, Testudines, and Crocodylia) species. The regional species richness is still considered underestimated, considering the taxonomic uncertainty, complexity and cryptic diversity of various species, as observed in other regions of the Amazon biome. Efforts for scientific collection and studies related to integrative taxonomy are needed to elucidate uncertainties and increase levels of knowledge of the local diversity. PMID:26691094

  11. Local late Amazonian boulder breakdown and denudation rate on Mars

    NARCIS (Netherlands)

    de Haas, T.; Hauber, E.; Kleinhans, M.G.

    2013-01-01

    Inactive fan surfaces become smoother and develop desert pavement over time by weathering and erosion. We use this mechanism to estimate late Amazonian boulder breakdown and surface denudation rates on a young (∼1.25 Ma) (Schon et al., 2009) fan on Mars. This is done by comparing boulder size and su

  12. A Miocene perspective on the evolution of the Amazonian biota

    NARCIS (Netherlands)

    Wesselingh, F.P.; Salo, J.A.

    2006-01-01

    Between c. 23 and 8 Ma, western Amazonia was occupied by the vast Pebas long-lived lake/wetland system. The Pebas system had a variety of influences over the evolution of Miocene and modern Amazonian biota; it formed a barrier for the exchange of terrestrial biota, a pathway for the transition of ma

  13. 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.

  14. Biological Scaling Problems and Solutions in Amphibians.

    Science.gov (United States)

    Levy, Daniel L; Heald, Rebecca

    2015-08-10

    Size is a primary feature of biological systems that varies at many levels, from the organism to its constituent cells and subcellular structures. Amphibians populate some of the extremes in biological size and have provided insight into scaling mechanisms, upper and lower size limits, and their physiological significance. Body size variation is a widespread evolutionary tactic among amphibians, with miniaturization frequently correlating with direct development that occurs without a tadpole stage. The large genomes of salamanders lead to large cell sizes that necessitate developmental modification and morphological simplification. Amphibian extremes at the cellular level have provided insight into mechanisms that accommodate cell-size differences. Finally, how organelles scale to cell size between species and during development has been investigated at the molecular level, because subcellular scaling can be recapitulated using Xenopus in vitro systems.

  15. Effects of Roads on Amphibian Populations

    DEFF Research Database (Denmark)

    Hels, T.

    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 toads was common knowledge to everybody due to personal experience: amphibians were abundant. Noisy and innumerable in spring when reproducing, silent and even more abundant in late summer with both adults and metamorphs leaving the breeding ponds. Today, experiencing frogs and toads is an event......, 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...

  16. 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.

  17. The structure of the Amazonian craton: Available geophysical evidence

    Science.gov (United States)

    Rosa, João Willy Corrêa; Rosa, José Wilson Corrêa; Fuck, Reinhardt A.

    2016-10-01

    The Amazonian craton, which covers a large area of South America, and is thought to have been stable since the end of the Mesoproterozoic, has recently benefited from a series of regional geophysical surveys. The Amazonian craton comprises the northern Guyana shield and the southern Central Brazil shield. It has become the main subject of seismological studies aiming to determine crustal thickness. Moho thickness maps that cover a large part of the South American continent summarize these studies. Receiver function studies, aided by surface wave dispersion tomography, were also useful tools applied in the region over the past decade. These have been improved by the addition of temporary and permanent regional seismological arrays and stations. An interesting NNW-SSE Moho depth anomaly, pointing to crustal thickening of up to 60 km in the central Guyana shield and a 50 km thick anomaly of the southern Central Brazil shield were recently identified. Areas with crustal thickening correspond to Paleoproterozoic magmatic arcs. The upper mantle seismic anisotropy in part of the region has been determined from SKS splitting studies. The currently available seismic anisotropy information shows that the orientation of the determined anisotropic axis is related to the frozen in anisotropy hypothesis for the Amazonian craton. The orientation of the anisotropic axis shows no relation to the current South American plate motion in the Amazonian craton. Most recently, detailed information for the two shields has benefited from a series of high-resolution, regional aerogeophysical surveys, made available by CPRM, the Brazilian Geological Survey. In addition to the mentioned contribution from seismology for imaging deeper crustal structures, regional gravity surveys have been expanded, adding to previous Bouguer anomaly maps, and deep drilling information from early exploration efforts have been compiled for the Amazon basin, which covers the Amazonian craton separating the Guyana

  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. Complex history of the amphibian-killing chytrid fungus revealed with genome resequencing data.

    Science.gov (United States)

    Rosenblum, Erica Bree; James, Timothy Y; Zamudio, Kelly R; Poorten, Thomas J; Ilut, Dan; Rodriguez, David; Eastman, Jonathan M; Richards-Hrdlicka, Katy; Joneson, Suzanne; Jenkinson, Thomas S; Longcore, Joyce E; Parra Olea, Gabriela; Toledo, Luís Felipe; Arellano, Maria Luz; Medina, Edgar M; Restrepo, Silvia; Flechas, Sandra Victoria; Berger, Lee; Briggs, Cheryl J; Stajich, Jason E

    2013-06-01

    Understanding the evolutionary history of microbial pathogens is critical for mitigating the impacts of emerging infectious diseases on economically and ecologically important host species. We used a genome resequencing approach to resolve the evolutionary history of an important microbial pathogen, the chytrid Batrachochytrium dendrobatidis (Bd), which has been implicated in amphibian declines worldwide. We sequenced the genomes of 29 isolates of Bd from around the world, with an emphasis on North, Central, and South America because of the devastating effect that Bd has had on amphibian populations in the New World. We found a substantial amount of evolutionary complexity in Bd with deep phylogenetic diversity that predates observed global amphibian declines. By investigating the entire genome, we found that even the most recently evolved Bd clade (termed the global panzootic lineage) contained more genetic variation than previously reported. We also found dramatic differences among isolates and among genomic regions in chromosomal copy number and patterns of heterozygosity, suggesting complex and heterogeneous genome dynamics. Finally, we report evidence for selection acting on the Bd genome, supporting the hypothesis that protease genes are important in evolutionary transitions in this group. Bd is considered an emerging pathogen because of its recent effects on amphibians, but our data indicate that it has a complex evolutionary history that predates recent disease outbreaks. Therefore, it is important to consider the contemporary effects of Bd in a broader evolutionary context and identify specific mechanisms that may have led to shifts in virulence in this system.

  20. Probiotic treatment restores protection against lethal fungal infection lost during amphibian captivity.

    Science.gov (United States)

    Kueneman, Jordan G; Woodhams, Douglas C; Harris, Reid; Archer, Holly M; Knight, Rob; McKenzie, Valerie J

    2016-09-28

    Host-associated microbiomes perform many beneficial functions including resisting pathogens and training the immune system. Here, we show that amphibians developing in captivity lose substantial skin bacterial diversity, primarily due to reduced ongoing input from environmental sources. We combined studies of wild and captive amphibians with a database of over 1 000 strains that allows us to examine antifungal function of the skin microbiome. We tracked skin bacterial communities of 62 endangered boreal toads, Anaxyrus boreas, across 18 time points, four probiotic treatments, and two exposures to the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd) in captivity, and compared these to 33 samples collected from wild populations at the same life stage. As the amphibians in captivity lost the Bd-inhibitory bacteria through time, the proportion of individuals exposed to Bd that became infected rose from 33% to 100% in subsequent exposures. Inoculations of the Bd-inhibitory probiotic Janthinobacterium lividum resulted in a 40% increase in survival during the second Bd challenge, indicating that the effect of microbiome depletion was reversible by restoring Bd-inhibitory bacteria. Taken together, this study highlights the functional role of ongoing environmental inputs of skin-associated bacteria in mitigating a devastating amphibian pathogen, and that long-term captivity decreases this defensive function. PMID:27655769

  1. 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.

  2. Ion transport by the amphibian primary ureter

    DEFF Research Database (Denmark)

    Møbjerg, Nadja

    2008-01-01

    and it is furthermore a key player in the induction of these kidney generations. Whether the ureter participates in urine modification, remains to be elucidated. In amphibians the pronephros is a large organ, which is functional for a considerable time before it degenerates. The aim of this study was to investigate...... 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...

  3. Amphibians as model to study endocrine disrupters.

    Science.gov (United States)

    Kloas, Werner; Lutz, Ilka

    2006-10-13

    Environmental compounds can interfere with endocrine systems of wildlife and humans. These so-called endocrine disrupters (ED) are known to affect reproductive biology and thyroid system. The classical model species for these endocrine systems are amphibians and therefore they can serve as sentinels for detection of the modes of action (MOAs) of ED. Recently, amphibians are being reviewed as suitable models to assess (anti)estrogenic and (anti)androgenic MOAs influencing reproductive biology as well as (anti)thyroidal MOAs interfering with the thyroid system. The development of targeted bioassays in combination with adequate chemical analyses is the prerequisite for a concise risk assessment of ED.

  4. Molecular identification of Amazonian stingless bees using polymerase chain reaction single-strand conformation polymorphism.

    Science.gov (United States)

    Souza, M T; Carvalho-Zilse, G A

    2014-01-01

    In countries containing a mega diversity of wildlife, such as Brazil, identifying and characterizing biological diversity is a continuous process for the scientific community, even in face of technological and scientific advances. This activity demands initiatives for the taxonomic identification of highly diverse groups, such as stingless bees, including molecular analysis strategies. This type of bee is distributed in all of the Brazilian states, with the highest species diversity being found in the State of Amazônia. However, the estimated number of species diverges among taxonomists. These bees are considered the main pollinators in the Amazon rainforest, in which they obtain food and shelter; however, their persistence is constantly threatened by deforestation pressure. Hence, it is important to classify the number and abundance of bee specie, to measure their decline and implement meaningful, priority conservation strategies. This study aims to maximize the implementation of more direct, economic and successful techniques for the taxonomic identification of stingless bees. Specifically, the genes 16S rRNA and COI from mitochondrial DNA were used as molecular markers to differentiate 9 species of Amazonian stingless bees based on DNA polymorphism, using the polymerase chain reaction-single-strand conformation polymorphism technique. We registered different, exclusive SSCP haplotypes for both genes in all species analyzed. These results demonstrate that SSCP is a simple and cost-effective technique that is applicable to the molecular identification of stingless bee species. PMID:25117306

  5. 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

  6. The state of amphibians in the United States

    Science.gov (United States)

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

    2012-01-01

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

  7. First evidence of Batrachochytrium dendrobatidis in China: discovery of chytridiomycosis in introduced American bullfrogs and native amphibians in the Yunnan Province, China.

    Science.gov (United States)

    Bai, Changming; Garner, Trenton W J; Li, Yiming

    2010-08-01

    Although the chytrid fungus Batrachochytrium dendrobatidis (Bd), the etiological agent of amphibian chytridiomycosis, has been implicated in mass mortality and population declines on several continents around the world, there have been no reports on the presence of Bd infections in amphibians in China. We employed quantitative PCR and histological techniques to investigate the presence of Bd in introduced North American bullfrogs (Rana catesbeiana) (referred to hereafter as bullfrog) and native amphibians in bullfrog-invaded areas of the Yunnan Province, China. A total of 259 samples at five wild sites were collected between June and September in 2007 and 2008, including bullfrogs and four native amphibian species (Rana pleuraden, Rana chaochiaoensis, Odorrana andersonii, and Bombina maxima). In addition, 37 samples of adult bullfrogs were obtained from a food market. Bd infections were discovered in bullfrogs and three native amphibian species from all of the surveyed sites. Of the 39 Bd-positive samples, 35 were from wild-caught bullfrog tadpoles, postmetamorphic bullfrogs, R. pleuraden, R. chaochiaoensis, and O. andersonii, and four were from adult bullfrogs from the market. Our results provide the first evidence of the presence of Bd in Chinese amphibians, suggesting that native amphibian diversity in China is at risk from Bd. There is an urgent need to monitor the distribution of Bd in amphibians in China and understand the susceptibility of native amphibian species to chytridiomycosis. Strict regulations on the transportation of bullfrogs and the breeding of bullfrogs in markets and farms should be drafted in order to stop the spread of Bd by bullfrogs.

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

    Science.gov (United States)

    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 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.

  9. 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)

  10. Hair mercury levels in Amazonian populations: spatial distribution and trends

    Directory of Open Access Journals (Sweden)

    Barbieri Flavia L

    2009-12-01

    Full Text Available Abstract Background Mercury is present in the Amazonian aquatic environments from both natural and anthropogenic sources. As a consequence, many riverside populations are exposed to methylmercury, a highly toxic organic form of mercury, because of their intense fish consumption. Many studies have analysed this exposure from different approaches since the early nineties. This review aims to systematize the information in spatial distribution, comparing hair mercury levels by studied population and Amazonian river basin, looking for exposure trends. Methods The reviewed papers were selected from scientific databases and online libraries. We included studies with a direct measure of hair mercury concentrations in a sample size larger than 10 people, without considering the objectives, approach of the study or mercury speciation. The results are presented in tables and maps by river basin, displaying hair mercury levels and specifying the studied population and health impact, if any. Results The majority of the studies have been carried out in communities from the central Amazonian regions, particularly on the Tapajós River basin. The results seem quite variable; hair mercury means range from 1.1 to 34.2 μg/g. Most studies did not show any significant difference in hair mercury levels by gender or age. Overall, authors emphasized fish consumption frequency as the main risk factor of exposure. The most studied adverse health effect is by far the neurological performance, especially motricity. However, it is not possible to conclude on the relation between hair mercury levels and health impact in the Amazonian situation because of the relatively small number of studies. Conclusions Hair mercury levels in the Amazonian regions seem to be very heterogenic, depending on several factors. There is no obvious spatial trend and there are many areas that have never been studied. Taking into account the low mercury levels currently handled as acceptable, the

  11. 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

  12. Developmental morphological diversity in caecilian amphibians : systematic and evolutionary implications

    NARCIS (Netherlands)

    Müller, Hendrik

    2007-01-01

    Caecilians, or Gymnophiona, constitute one of the three extant orders of the Recent Amphibia and are the least known, major living tetrapod clade. Compared to frogs and salamanders, caecilians have an unusual skull morphology. Earlier reports of an unusually high number of individual skull ossificat

  13. Isozyme characterization of Capsicum accessions from the Amazonian Colombian collection

    Directory of Open Access Journals (Sweden)

    Lorena Quintero Barrera

    2007-02-01

    Full Text Available Two hundred and sixty-one accessions of the genus Capsicum were obtained from the Colombian Amazonian germplasm bank at Amazonian Institute of Scientific Research (Sinchi and were evaluated with five polymorphic enzymatic systems, including esterase (EST, peroxidase (PRX, 6-phosphogluconate dehydrogenase (6-PGDH, aspartate amino transferase (GOT, and malic enzyme (ME. Using a cluster analysis (UPGMA the genetic variability of these accessions were characterized. Grouping of the species C. baccatum and C. pubescens were observed, while the species C. annuum, C. chinense and C. frutescens did not group independently, a result that has been previously reported in isoenzyme analyses of this genus. Several accessions were deemed of particular interest for future ecological and evolutive studies. Key words: Colombia, Capsicum, germplasm bank, isoenzymes, peppers.

  14. Fish complementarity is associated to forests in Amazonian streams

    Directory of Open Access Journals (Sweden)

    Carolina Rodrigues Bordignon

    2015-09-01

    Full Text Available The functional structure of communities is commonly measured by the variability in functional traits, which may demonstrate complementarity or redundancy patterns. In this study, we tested the influence of environmental variables on the functional structure of fish assemblages in Amazonian streams within a deforestation gradient. We calculated six ecomorphological traits related to habitat use from each fish species, and used them to calculate the net relatedness index (NRI and the nearest taxon index (NTI. The set of species that used the habitat differently (complementary or overdispersed assemblages occurred in sites with a greater proportion of forests. The set of species that used the habitat in a similar way (redundant or clustered assemblages occurred in sites with a greater proportion of grasses in the stream banks. Therefore, the deforestation of entire watersheds, which has occurred in many Amazonian regions, may be a central factor for the functional homogenization of fish fauna.

  15. Sleep in amphibians and reptiles: a review and a preliminary analysis of evolutionary patterns.

    Science.gov (United States)

    Libourel, Paul-Antoine; Herrel, Anthony

    2016-08-01

    Despite the ubiquitous nature of sleep, its functions remain a mystery. In an attempt to address this, many researchers have studied behavioural and electrophysiological phenomena associated with sleep in a diversity of animals. The great majority of vertebrates and invertebrates display a phase of immobility that could be considered as a sort of sleep. Terrestrial mammals and birds, both homeotherms, show two sleep states with distinct behavioural and electrophysiological features. However, whether these features have evolved independently in each clade or were inherited from a common ancestor remains unknown. Unfortunately, amphibians and reptiles, key taxa in understanding the evolution of sleep given their position at the base of the tetrapod and amniote tree, respectively, remain poorly studied in the context of sleep. This review presents an overview of what is known about sleep in amphibians and reptiles and uses the existing data to provide a preliminary analysis of the evolution of behavioural and electrophysiological features of sleep in amphibians and reptiles. We also discuss the problems associated with analysing existing data, as well as the difficulty in inferring homologies of sleep stages based on limited data in the context of an essentially mammalian-centric definition of sleep. Finally, we highlight the importance of developing comparative approaches to sleep research that may benefit from the great diversity of species with different ecologies and morphologies in order to understand the evolution and functions of sleep. PMID:26031314

  16. Alluvial plain dynamics in the southern Amazonian foreland basin

    OpenAIRE

    Lombardo, U

    2015-01-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation ...

  17. The impact of Amazonian deforestation on Amazon basin rainfall

    OpenAIRE

    Spracklen, DV; Garcia-Carreras, L.

    2015-01-01

    We completed a meta-analysis of regional and global climate model simulations (n=96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12±11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simu...

  18. Karyomegaly in Baryancistrus sp. (Loricaridae) from Amazonian Brazil.

    Science.gov (United States)

    Paperna, I; Di Cave, D

    2001-06-20

    Vesicular karyomegaly of the liver hepatocytes is described from Baryancistrus sp. (Loricaridae), in 3 out of 7 fish, collected from Rio Xingu in central Amazonian (neutral water) Brazil and kept about 2 wk in a holding facility fed with acid water (pH 5.0 to 5.5). Altered cells also occurred in the gill epithelium. The vesicles in the liver were shown to contain a periodic acid-Schiff (PAS)-positive substance or residue.

  19. Detection of Amazonian Black Earth Sites using Hyperspectral Satellite Imagery

    Science.gov (United States)

    Braswell, B. H.; Palace, M.; Bush, M. B.; Neves, E.; Mcmichael, C.; Czarnecki, C.; Moraes, B.; Raczka, M.

    2012-12-01

    The pre-Columbian indigenous population estimates of the Amazon Basin lowlands are highly uncertain and the subject of considerable controversy. One of the archaeological sources used in reconstruction of Amazonian societies are Amazonian black earths (ABE) or terra preta soils. The immense size of Amazonia, remoteness of many areas, forest vegetation, and lack of archaeological field surveys, make remote sensing beneficial to archaeological studies in this region. Remote sensing allows for comparison and analysis of vegetation across vast areas. Previous research has shown that hyperspectral image data can detect vegetation canopy chemistry differences, associated with soil nutrients and chemistry anomalies at ABE locations. We conducted a preliminary analysis that indicates nine portions of the spectrum where three ABE sites are completely separable from the three non-ABE sites. A discriminant function analysis using stepwise variable selection indicated that five bands were adequate in distinguishing between ABE and non-ABE sites. These five bands ranged between the 2000-2400 nm, indicating that canopy moisture is useful in remotely sensing terra preta. The wealth of site locations we are compiling from numerous sources provides a unique opportunity to develop algorithms for the classification of ABE and non-ABE sites. Our current data holdings include over 1600 Hyperion images and a database of ABE/ non-ABE field observations at approximately 2900 sites. The distribution and number of ABE sites provides information useful for both archaeological research and has consequences for the interpretation of Amazonian forest ecology. Knowledge of the disturbance history of the Amazonian forest provides a context and framework for the placement of all environmental research in the region. This presentation reports results of statistical modeling using extracted spectra from about 400 sites that are within Hyperion scenes.

  20. Poor Prospects for Avian Biodiversity in Amazonian Oil Palm

    OpenAIRE

    Lees, Alexander C.; Moura, Nárgila G.; Arlete Silva de Almeida; Ima C G Vieira

    2015-01-01

    Expansion of oil palm plantations across the humid tropics has precipitated massive loss of tropical forest habitats and their associated speciose biotas. Oil palm plantation monocultures have been identified as an emerging threat to Amazonian biodiversity, but there are no quantitative studies exploring the impact of these plantations on the biome's biota. Understanding these impacts is extremely important given the rapid projected expansion of oil palm cultivation in the basin. Here we inve...

  1. Joy within tranquility: Amazonian Urarina styles of happiness

    OpenAIRE

    Walker, Harry

    2015-01-01

    Enjoyment in life among Amazonian Urarina is examined through the lens of two contrastive concepts of happiness. The first, “tranquility,” is a relatively long-term, relational condition implying emotional spontaneity and a flexible, freely chosen work routine that allows for a merging of action and awareness. It epitomizes a broader concern with the development of an individual “style of life,” where attitudes, manners, and actions come into alignment. The second concept, “joy...

  2. Amphibian nitrate stress as an additional terrestrial threat from astrophysical ionizing radiation events?

    CERN Document Server

    Thomas, Brian C

    2008-01-01

    As diversity in amphibian species declines, the search for causes has intensified. Work in this area has shown that amphibians are especially susceptible to the combination of heightened UVB radiation and increased nitrate concentrations. Various astrophysical events have been suggested as sources of ionizing radiation that could pose a threat to life on Earth, through destruction of the ozone layer and subsequent increase in UVB, followed by deposition of nitrate. In this study, we investigate whether the nitrate deposition following an ionizing event is sufficiently large to cause an additional stress beyond that of the heightened UVB previously considered. We have converted predicted nitrate depositions to concentration values, utilizing data from the New York State Department of Environmental Conservation Acid Rain Monitoring Network web site. Our results show that the increase in nitrate concentration in bodies of water following the most intense ionization event likely in the last billion years would no...

  3. 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.

  4. High levels of diversity uncovered in a widespread nominal taxon: continental phylogeography of the neotropical tree frog Dendropsophus minutus.

    Directory of Open Access Journals (Sweden)

    Marcelo Gehara

    Full Text Available Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI and the 16S rhibosomal gene (16S for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered.

  5. High levels of diversity uncovered in a widespread nominal taxon: continental phylogeography of the neotropical tree frog Dendropsophus minutus.

    Science.gov (United States)

    Gehara, Marcelo; Crawford, Andrew J; Orrico, Victor G D; Rodríguez, Ariel; Lötters, Stefan; Fouquet, Antoine; Barrientos, Lucas S; Brusquetti, Francisco; De la Riva, Ignacio; Ernst, Raffael; Urrutia, Giuseppe Gagliardi; Glaw, Frank; Guayasamin, Juan M; Hölting, Monique; Jansen, Martin; Kok, Philippe J R; Kwet, Axel; Lingnau, Rodrigo; Lyra, Mariana; Moravec, Jiří; Pombal, José P; Rojas-Runjaic, Fernando J M; Schulze, Arne; Señaris, J Celsa; Solé, Mirco; Rodrigues, Miguel Trefaut; Twomey, Evan; Haddad, Celio F B; Vences, Miguel; Köhler, Jörn

    2014-01-01

    Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI) and the 16S rhibosomal gene (16S) for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered. PMID:25208078

  6. Direct and indirect effects of climate change on amphibian populations

    Science.gov (United States)

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

    2010-01-01

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

  7. Hyperdominance in the Amazonian tree flora.

    Science.gov (United States)

    ter Steege, Hans; Pitman, Nigel C A; Sabatier, Daniel; Baraloto, Christopher; Salomão, Rafael P; Guevara, Juan Ernesto; Phillips, Oliver L; Castilho, Carolina V; Magnusson, William E; Molino, Jean-François; Monteagudo, Abel; Núñez Vargas, Percy; Montero, Juan Carlos; Feldpausch, Ted R; Coronado, Eurídice N Honorio; Killeen, Tim J; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Terborgh, John; Wittmann, Florian; Andrade, Ana; Laurance, William F; Laurance, Susan G W; Marimon, Beatriz S; Marimon, Ben-Hur; Guimarães Vieira, Ima Célia; Amaral, Iêda Leão; Brienen, Roel; Castellanos, Hernán; Cárdenas López, Dairon; Duivenvoorden, Joost F; Mogollón, Hugo F; Matos, Francisca Dionízia de Almeida; Dávila, Nállarett; García-Villacorta, Roosevelt; Stevenson Diaz, Pablo Roberto; Costa, Flávia; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Montoya, Alvaro Javier Duque; Fernandez Piedade, Maria Teresa; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Gribel, Rogerio; Fine, Paul V A; Peres, Carlos A; Toledo, Marisol; Aymard C, Gerardo A; Baker, Tim R; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Maas, Paul; Petronelli, Pascal; Stropp, Juliana; Zartman, Charles Eugene; Daly, Doug; Neill, David; Silveira, Marcos; Paredes, Marcos Ríos; Chave, Jerome; Lima Filho, Diógenes de Andrade; Jørgensen, Peter Møller; Fuentes, Alfredo; Schöngart, Jochen; Cornejo Valverde, Fernando; Di Fiore, Anthony; Jimenez, Eliana M; Peñuela Mora, Maria Cristina; Phillips, Juan Fernando; Rivas, Gonzalo; van Andel, Tinde R; von Hildebrand, Patricio; Hoffman, Bruce; Zent, Eglée L; Malhi, Yadvinder; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vos, Vincent; Zent, Stanford; Oliveira, Alexandre A; Schutz, Angela Cano; Gonzales, Therany; Trindade Nascimento, Marcelo; Ramirez-Angulo, Hirma; Sierra, Rodrigo; Tirado, Milton; Umaña Medina, María Natalia; van der Heijden, Geertje; Vela, César I A; Vilanova Torre, Emilio; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; Ferreira, Cid; Mesones, Italo; Torres-Lezama, Armando; Urrego Giraldo, Ligia Estela; Zagt, Roderick; Alexiades, Miguel N; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Palacios Cuenca, Walter; Pauletto, Daniela; Valderrama Sandoval, Elvis; Valenzuela Gamarra, Luis; Dexter, Kyle G; Feeley, Ken; Lopez-Gonzalez, Gabriela; Silman, Miles R

    2013-10-18

    The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community. PMID:24136971

  8. Pesticide Detection in Rainwater, Stemflow, and Amphibians from Agricultural Spray Drift in Southern Georgia, USA

    Science.gov (United States)

    Amphibians are important sentinel environmental species since they integrate stressors from both aquatic and terrestrial ecosystems. Pesticides are well established as a significant stressor for amphibians. In order to study spray-drift contributions to amphibian habitats, pestic...

  9. Pesticide Uptake Across the Amphibian Dermis Through Soil and Overspray Exposures

    Science.gov (United States)

    For terrestrial amphibians, accumulation ofpesticides through dermal contact is a primary route ofexposure in agricultural landscapes and may be contributingto widespread amphibian declines. To show pesticidetransfer across the amphibian dermis at permitted labelapplication rates...

  10. 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.

  11. Neurosteroid biosynthesis in the brain of amphibians

    Directory of Open Access Journals (Sweden)

    Hubert eVaudry

    2011-11-01

    Full Text Available Amphibians have been widely used to investigate the synthesis of biologically active steroids in the brain and the regulation of neurosteroid production by neurotransmitters and neuropeptides. The aim of the present review is to summarize the current knowledge regarding the neuroanatomical distribution and biochemical activity of steroidogenic enzymes in the brain of anurans and urodeles. The data accumulated over the past two decades demonstrate that discrete populations of neurons and/or glial cells in the frog and newt brains express the major steroidogenic enzymes and are able to synthesize de novo a number of neurosteroids from cholesterol/pregnenolone. Since neurosteroidogenesis has been conserved during evolution from amphibians to mammals, it appears that neurosteroids must play important physiological functions in the central nervous system of vertebrates

  12. From Amazonia to the Atlantic forest: molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges.

    Science.gov (United States)

    Fouquet, Antoine; Loebmann, Daniel; Castroviejo-Fisher, Santiago; Padial, José M; Orrico, Victor G D; Lyra, Mariana L; Roberto, Igor Joventino; Kok, Philippe J R; Haddad, Célio F B; Rodrigues, Miguel T

    2012-11-01

    Documenting the Neotropical amphibian diversity has become a major challenge facing the threat of global climate change and the pace of environmental alteration. Recent molecular phylogenetic studies have revealed that the actual number of species in South American tropical forests is largely underestimated, but also that many lineages are millions of years old. The genera Phyzelaphryne (1 sp.) and Adelophryne (6 spp.), which compose the subfamily Phyzelaphryninae, include poorly documented, secretive, and minute frogs with an unusual distribution pattern that encompasses the biotic disjunction between Amazonia and the Atlantic forest. We generated >5.8 kb sequence data from six markers for all seven nominal species of the subfamily as well as for newly discovered populations in order to (1) test the monophyly of Phyzelaphryninae, Adelophryne and Phyzelaphryne, (2) estimate species diversity within the subfamily, and (3) investigate their historical biogeography and diversification. Phylogenetic reconstruction confirmed the monophyly of each group and revealed deep subdivisions within Adelophryne and Phyzelaphryne, with three major clades in Adelophryne located in northern Amazonia, northern Atlantic forest and southern Atlantic forest. Our results suggest that the actual number of species in Phyzelaphryninae is, at least, twice the currently recognized species diversity, with almost every geographically isolated population representing an anciently divergent candidate species. Such results highlight the challenges for conservation, especially in the northern Atlantic forest where it is still degraded at a fast pace. Molecular dating revealed that Phyzelaphryninae originated in Amazonia and dispersed during early Miocene to the Atlantic forest. The two Atlantic forest clades of Adelophryne started to diversify some 7 Ma minimum, while the northern Amazonian Adelophryne diversified much earlier, some 13 Ma minimum. This striking biogeographic pattern coincides with

  13. Estimating the global conservation status of more than 15,000 Amazonian tree species

    DEFF Research Database (Denmark)

    ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.;

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree ...

  14. Ranavirus outbreaks in amphibian populations of northern Idaho

    Science.gov (United States)

    Russell, Danelle M.; Goldberg, Caren S.; Sprague, Laura; Waits, Lisette P.; Green, D. Earl; Schuler, Krysten L.; Rosenblum, Erica Bree

    2011-01-01

    Ranavirus outbreaks, caused by pathogens in the genus Ranavirus (Family Iridoviridae), were the largest single cause of reported amphibian mass mortality events in the United States from 1996–2001 (Green et al. 2002). Mortality events associated with ranaviruses have been documented on five continents and throughout the latitudes and elevations where amphibians occur (Gray et al. 2009). However, the threat of ranaviruses to amphibian and reptile populations in specific regions is still largely unknown (Chinchar 2002; Gray et al. 2009).

  15. 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...

  16. 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 ...

  17. 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.

  18. 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...

  19. Book review: The ecology and behavior of amphibians

    Science.gov (United States)

    Walls, Susan C.

    2008-01-01

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

  20. Status and trends of amphibian declines and extinctions worldwide.

    Science.gov (United States)

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

    2004-12-01

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

  1. Collapse of amphibian communities due to an introduced Ranavirus.

    Science.gov (United States)

    Price, Stephen J; Garner, Trenton W J; Nichols, Richard A; Balloux, François; Ayres, César; Mora-Cabello de Alba, Amparo; Bosch, Jaime

    2014-11-01

    The emergence of infectious diseases with a broad host range can have a dramatic impact on entire communities and has become one of the main threats to biodiversity. Here, we report the simultaneous exploitation of entire communities of potential hosts with associated severe declines following invasion by a novel viral pathogen. We found two phylogenetically related, highly virulent viruses (genus Ranavirus, family Iridoviridae) causing mass mortality in multiple, diverse amphibian hosts in northern Spain, as well as a third, relatively avirulent virus. We document host declines in multiple species at multiple sites in the region. Our work reveals a group of pathogens that seem to have preexisting capacity to infect and evade immunity in multiple diverse and novel hosts, and that are exerting massive impacts on host communities. This report provides an exceptional record of host population trends being tracked in real time following emergence of a wildlife disease and a striking example of a novel, generalist pathogen repeatedly crossing the species barrier with catastrophic consequences at the level of host communities.

  2. Forest structure and carbon dynamics in Amazonian tropical rain forests.

    Science.gov (United States)

    Vieira, Simone; de Camargo, Plinio Barbosa; Selhorst, Diogo; da Silva, Roseana; Hutyra, Lucy; Chambers, Jeffrey Q; Brown, I Foster; Higuchi, Niro; dos Santos, Joaquim; Wofsy, Steven C; Trumbore, Susan E; Martinelli, Luiz Antonio

    2004-08-01

    Living trees constitute one of the major stocks of carbon in tropical forests. A better understanding of variations in the dynamics and structure of tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon, and for understanding how they recover from disturbance. Amazonian tropical forests occur over a vast area that encompasses differences in topography, climate, and geologic substrate. We observed large differences in forest structure, biomass, and tree growth rates in permanent plots situated in the eastern (near Santarém, Pará), central (near Manaus, Amazonas) and southwestern (near Rio Branco, Acre) Amazon, which differed in dry season length, as well as other factors. Forests at the two sites experiencing longer dry seasons, near Rio Branco and Santarém, had lower stem frequencies (460 and 466 ha(-1) respectively), less biodiversity (Shannon-Wiener diversity index), and smaller aboveground C stocks (140.6 and 122.1 Mg C ha(-1)) than the Manaus site (626 trees ha(-1), 180.1 Mg C ha(-1)), which had less seasonal variation in rainfall. The forests experiencing longer dry seasons also stored a greater proportion of the total biomass in trees with >50 cm diameter (41-45 vs 30% in Manaus). Rates of annual addition of C to living trees calculated from monthly dendrometer band measurements were 1.9 (Manaus), 2.8 (Santarém), and 2.6 (Rio Branco) Mg C ha(-1) year(-1). At all sites, trees in the 10-30 cm diameter class accounted for the highest proportion of annual growth (38, 55 and 56% in Manaus, Rio Branco and Santarém, respectively). Growth showed marked seasonality, with largest stem diameter increment in the wet season and smallest in the dry season, though this may be confounded by seasonal variation in wood water content. Year-to-year variations in C allocated to stem growth ranged from nearly zero in Rio Branco, to 0.8 Mg C ha(-1) year(-1) in Manaus (40% of annual mean) and 0.9 Mg C ha(-1) year(-1) (33% of

  3. Conceptual Design for the Amphibian Research and Monitoring Initiative (ARMI)

    Science.gov (United States)

    Battaglin, W. A.; Langtimm, C. A.; Adams, M. J.; Gallant, A. L.; James, D. L.

    2001-12-01

    In 2000, the President of the United States (US) and Congress directed Department of Interior (DOI) agencies to develop a program for monitoring trends in amphibian populations on DOI lands and to conduct research into causes of declines. The U.S. Geological Survey (USGS) was given lead responsibility for planning and implementing the Amphibian Research and Monitoring Initiative (ARMI) in cooperation with the National Park Service (NPS), Fish and Wildlife Service, and Bureau of Land Management. The program objectives are to (1) establish a network for monitoring the status and distribution of amphibian species on DOI lands; (2) identify and monitor environmental conditions known to affect amphibian populations; (3) conduct research on causes of amphibian population change and malformations; and (4) provide information to resource managers, policy makers, and the public in support of amphibian conservation. The ARMI program will integrate research efforts of USGS, other Federal, and non-federal herpetologists, hydrologists, and geographers across the Nation. ARMI will conduct a small number (~20) of intensive research efforts (for example, studies linking amphibian population changes to hydrologic conditions) and a larger number (~50) of more generalized inventory and monitoring studies encompassing broader areas such as NPS units. ARMI will coordinate with and try to augment other amphibian inventory studies such as the National Amphibian Atlas and the North American Amphibian Monitoring Program. ARMI will develop and test protocols for the standardized collection of amphibian data and provide a centrally managed database designed to simplify data entry, retrieval, and analysis. ARMI pilot projects are underway at locations across the US.

  4. 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

  5. Amazonian Triatomine Biodiversity and the Transmission of Chagas Disease in French Guiana: In Medio Stat Sanitas.

    Science.gov (United States)

    Péneau, Julie; Nguyen, Anne; Flores-Ferrer, Alheli; Blanchet, Denis; Gourbière, Sébastien

    2016-02-01

    The effects of biodiversity on the transmission of infectious diseases now stand as a cornerstone of many public health policies. The upper Amazonia and Guyana shield are hot-spots of biodiversity that offer genuine opportunities to explore the relationship between the risk of transmission of Chagas disease and the diversity of its triatomine vectors. Over 730 triatomines were light-trapped in four geomorphological landscapes shaping French-Guiana, and we determined their taxonomic status and infection by Trypanosoma cruzi. We used a model selection approach to unravel the spatial and temporal variations in species abundance, diversity and infection. The vector community in French-Guiana is typically made of one key species (Panstrongylus geniculatus) that is more abundant than three secondary species combined (Rhodnius pictipes, Panstrongylus lignarius and Eratyrus mucronatus), and four other species that complete the assemblage. Although the overall abundance of adult triatomines does not vary across French-Guiana, their diversity increases along a coastal-inland gradient. These variations unravelled a non-monotonic relationship between vector biodiversity and the risk of transmission of Chagas disease, so that intermediate biodiversity levels are associated with the lowest risks. We also observed biannual variations in triatomine abundance, representing the first report of a biannual pattern in the risk of Chagas disease transmission. Those variations were highly and negatively correlated with the average monthly rainfall. We discuss the implications of these patterns for the transmission of T. cruzi by assemblages of triatomine species, and for the dual challenge of controlling Amazonian vector communities that are made of both highly diverse and mostly intrusive species.

  6. Richness and composition of macrophyte assemblages in four Amazonian lakes - doi: 10.4025/actascibiolsci.v35i3.11602

    Directory of Open Access Journals (Sweden)

    Sidinei Magela Thomaz

    2013-08-01

    Full Text Available Aquatic macrophytes are an important component in the structure of lakes in Neotropical floodplains, for example, because they support a high diversity of invertebrates and vertebrates. In this paper, we tested whether or not the variability of macrophyte assemblages is lower in spatially close quadrats than among quadrats of different lakes. The study was carried in four lakes in a large Amazonian floodplain (Purus river, where floating meadows were investigated. A total of 49 taxa of macrophytes were found. Five species dominated and three species were rare. Taxa richness, composition and beta diversity differed more between than within lakes. Because high beta diversity was found among the lakes, they should be considered individually important for maintaining the gamma diversity of macrophytes within the Purus River floodplain, and this should be considered in plans of lake management.  

  7. Chytridiomycosis and amphibian population declines continue to spread eastward in Panama.

    Science.gov (United States)

    Woodhams, Douglas C; Kilburn, Vanessa L; Reinert, Laura K; Voyles, Jamie; Medina, Daniel; Ibáñez, Roberto; Hyatt, Alex D; Boyle, Donna G; Pask, James D; Green, David M; Rollins-Smith, Louise A

    2008-09-01

    Chytridiomycosis is a globally emerging disease of amphibians and the leading cause of population declines and extirpations at species-diverse montane sites in Central America. We continued long-term monitoring efforts for the presence of the fungal pathogen Batrachochytrium dendrobatidis (Bd) and for amphibian populations at two sites in western Panama, and we began monitoring at three new sites to the east. Population declines associated with chytridiomycosis emergence were detected at Altos de Campana National Park. We also detected Bd in three species east of the Panama Canal at Soberanía National Park, and prevalence data suggests that Bd may be enzootic in the lowlands of the park. However, no infected frogs were found further east at Tortí (prevalence amphibian communities east of the canal are at risk. Precise predictions of future disease emergence events are not possible until factors underlying disease emergence, such as dispersal, are understood. However, if the fungal pathogen spreads in a pattern consistent with previous disease events in Panama, then detection of Bd at Tortí and other areas east of the Panama Canal is imminent. Therefore, development of new management strategies and increased precautions for tourism, recreation, and biology are urgently needed.

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

    Science.gov (United States)

    Dias, Iuri Ribeiro; Medeiros, Tadeu Teixeira; Vila Nova, Marcos Ferreira; Solé, Mirco

    2014-01-01

    We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km(2) 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 distributed in 15 families: Aromobatidae (1), Brachycephalidae (3), Bufonidae (4), Centrolenidae (2), Ceratophryidae (1), Craugastoridae (7), Eleutherodactylidae (2), Hemiphractidae (2), Hylidae (42), Hylodidae (1), Leptodactylidae (7), Microhylidae (3), Siphonopidae (1), Odontophrynidae (3) and Pipidae (1). Species richness was positively correlated with monthly rainfall. Near 36% of the species were found in strictly forest environments, 15% are endemic to Bahia State and 77.2% are endemic to the Atlantic Forest biome. The large species diversity of this small area, the high degree of endemism and the taxonomic and biogeographic significance turn the Serra Bonita mountain into a hotpoint for amphibians within Brazil's Atlantic Forest hotspot. PMID:25408616

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

    Directory of Open Access Journals (Sweden)

    Iuri Dias

    2014-10-01

    Full Text Available 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 distributed in 15 families: Aromobatidae (1, Brachycephalidae (3, Bufonidae (4, Centrolenidae (2, Ceratophryidae (1, Craugastoridae (7, Eleutherodactylidae (2, Hemiphractidae (2, Hylidae (42, Hylodidae (1, Leptodactylidae (7, Microhylidae (3, Siphonopidae (1, Odontophrynidae (3 and Pipidae (1. Species richness was positively correlated with monthly rainfall. Near 36% of the species were found in strictly forest environments, 15% are endemic to Bahia State and 77.2% are endemic to the Atlantic Forest biome. The large species diversity of this small area, the high degree of endemism and the taxonomic and biogeographic significance turn the Serra Bonita mountain into a hotpoint for amphibians within Brazil’s Atlantic Forest hotspot.

  10. Amphibians and reptiles of Guyana, South America: illustrated keys, annotated species accounts, and a biogeographic synopsis

    Science.gov (United States)

    Cole, Charles J.; Townsend, Carol R.; Reynolds, Robert P.; MacCulloch, Ross D.; Lathrop, Amy

    2013-01-01

    Guyana has a very distinctive herpetofauna. In this first ever detailed modern accounting, based on voucher specimens, we document the presence of 324 species of amphibians and reptiles in the country; 148 amphibians, 176 reptiles. Of these, we present species accounts for 317 species and color photographs of about 62% (Plates 1–40). At the rate that new species are being described and distributional records are being found for the first time, we suspect that at least 350 species will be documented in a few decades. The diverse herpetofauna includes 137 species of frogs and toads, 11 caecilians, 4 crocodylians, 4 amphisbaenians, 56 lizards, 97 snakes, and 15 turtles. Endemic species, which occur nowhere else in the world, comprise 15% of the herpetofauna. Most of the endemics are amphibians, comprising 27% of the amphibian fauna. Type localities (where the type specimens or scientific name-bearers of species were found) are located within Guyana for 24% of the herpetofauna, or 36% of the amphibians. This diverse fauna results from the geographic position of Guyana on the Guiana Shield and the isolated highlands or tepuis of the eastern part of the Pantepui Region, which are surrounded by lowland rainforest and savannas. Consequently, there is a mixture of local endemic species and widespread species characteristic of Amazonia and the Guianan Region. Although the size of this volume may mislead some people into thinking that a lot is known about the fauna of Guyana, the work has just begun. Many of the species are known from fewer than five individuals in scientific collections; for many the life history, distribution, ecology, and behavior remain poorly known; few resources in the country are devoted to developing such knowledge; and as far as we are aware, no other group of animals in the fauna of Guyana has been summarized in a volume such as this to document the biological resources. We briefly discuss aspects of biogeography, as reflected in samples collected

  11. Alluvial plain dynamics in the southern Amazonian foreland basin

    Directory of Open Access Journals (Sweden)

    U. Lombardo

    2015-10-01

    Full Text Available Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays triggered by above normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all the twelve tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. I found that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid- to late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a year to decade time scale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  12. Alluvial plain dynamics in the southern Amazonian foreland basin

    Science.gov (United States)

    Lombardo, Umberto

    2016-05-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays and sheet sands triggered by above-normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all 12 tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. The data suggest that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid-to-late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a yearly to decadal timescale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  13. Environmental change and the carbon balance of Amazonian forests.

    Science.gov (United States)

    Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

    2014-11-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. PMID:25324039

  14. Amazonian Buriti oil: chemical characterization and antioxidant potential

    OpenAIRE

    Speranza, P.; de Oliveira Falcão, A.; Alves Macedo, J.; da Silva, L. H.M.; da C. Rodrigues, A. M.; Alves Macedo, G.

    2016-01-01

    Buriti oil is an example of an Amazonian palm oil of economic importance. The local population uses this oil for the prevention and treatment of different diseases; however, there are few studies in the literature that evaluate its properties. In this study, detailed chemical and antioxidant properties of Buriti oil were determined. The predominant fatty acid was oleic acid (65.6%) and the main triacylglycerol classes were tri-unsaturated (50.0%) and di-unsaturated-mono-saturated (39.3%) tria...

  15. 50 CFR 17.43 - Special rules-amphibians.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-amphibians. 17.43 Section 17.43 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—amphibians. (a) San Marcos salamander (Eurycea nana). (1) All provisions of § 17.31 apply...

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

    Science.gov (United States)

    2000

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

  17. AMPHIBIAN DECLINES AND ENVIRONMENTAL CHANGE IN THE EASTERN "MOJAVE DESERT"

    Science.gov (United States)

    A number of amphibian species historically inhabited sparsely distributed wetlands in the Mojave Desert, USA, habitats that have been dramatically altered or eliminated as a result of human activities. The population status and distribution of amphibians were investigated in a 20...

  18. 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…

  19. 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.

  20. Partners in amphibian and reptile conservation 2013 annual report

    Science.gov (United States)

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

    2014-01-01

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

  1. Composition of the Cutaneous Bacterial Community in Japanese Amphibians: Effects of Captivity, Host Species, and Body Region.

    Science.gov (United States)

    Sabino-Pinto, Joana; Bletz, Molly Catherine; Islam, Mohammed Mafizul; Shimizu, Norio; Bhuju, Sabin; Geffers, Robert; Jarek, Michael; Kurabayashi, Atsushi; Vences, Miguel

    2016-08-01

    The cutaneous microbiota plays a significant role in the biology of their vertebrate hosts, and its composition is known to be influenced both by host and environment, with captive conditions often altering alpha diversity. Here, we compare the cutaneous bacterial communities of 61 amphibians (both wild and captive) from Hiroshima, Japan, using high-throughput amplicon sequencing of a segment of the 16S rRNA gene. The majority of these samples came from a captive breeding facility at Hiroshima University where specimens from six species are maintained under highly standardized conditions for several generations. This allowed to identify host effects on the bacterial communities under near identical environmental conditions in captivity. We found the structure of the cutaneous bacterial community significantly differing between wild and captive individuals of newts, Cynops pyrrhogaster, with a higher alpha diversity found in the wild individuals. Community structure also showed distinct patterns when comparing different species of amphibians kept under highly similar conditions, revealing an intrinsic host effect. Bacterial communities of dorsal vs. ventral skin surfaces did not significantly differ in most species, but a trend of higher alpha diversity on the ventral surface was found in Oriental fire-bellied toads, Bombina orientalis. This study confirms the cutaneous microbiota of amphibians as a highly dynamic system influenced by a complex interplay of numerous factors.

  2. Composition of the Cutaneous Bacterial Community in Japanese Amphibians: Effects of Captivity, Host Species, and Body Region.

    Science.gov (United States)

    Sabino-Pinto, Joana; Bletz, Molly Catherine; Islam, Mohammed Mafizul; Shimizu, Norio; Bhuju, Sabin; Geffers, Robert; Jarek, Michael; Kurabayashi, Atsushi; Vences, Miguel

    2016-08-01

    The cutaneous microbiota plays a significant role in the biology of their vertebrate hosts, and its composition is known to be influenced both by host and environment, with captive conditions often altering alpha diversity. Here, we compare the cutaneous bacterial communities of 61 amphibians (both wild and captive) from Hiroshima, Japan, using high-throughput amplicon sequencing of a segment of the 16S rRNA gene. The majority of these samples came from a captive breeding facility at Hiroshima University where specimens from six species are maintained under highly standardized conditions for several generations. This allowed to identify host effects on the bacterial communities under near identical environmental conditions in captivity. We found the structure of the cutaneous bacterial community significantly differing between wild and captive individuals of newts, Cynops pyrrhogaster, with a higher alpha diversity found in the wild individuals. Community structure also showed distinct patterns when comparing different species of amphibians kept under highly similar conditions, revealing an intrinsic host effect. Bacterial communities of dorsal vs. ventral skin surfaces did not significantly differ in most species, but a trend of higher alpha diversity on the ventral surface was found in Oriental fire-bellied toads, Bombina orientalis. This study confirms the cutaneous microbiota of amphibians as a highly dynamic system influenced by a complex interplay of numerous factors. PMID:27278778

  3. Holocene paleoenvironmental reconstruction in the Eastern Amazonian Basin: Comprido Lake

    Science.gov (United States)

    Moreira, L. S.; Moreira-Turcq, P.; Cordeiro, R. C.; Turcq, B.; Caquineau, S.; Viana, J. C. C.; Brandini, N.

    2013-07-01

    Two sediment cores were studied from Comprido Lake, a black water floodplain lake located near Monte Alegre City, Eastern Amazonian Basin. The total organic carbon (TOC), nitrogen content (TN), δ13CTOC, sedimentary chlorophyll, diatom record and mineralogical composition revealed different hydrological and climatic regimes during the Holocene. Between 10,300 and 7800 cal yr BP, a dry climate was suggested by low values of TOC and chlorophyll derivatives concentrations that are related to the development of a C4 grasses on unflooded mud banks. A gap in sedimentation due to a complete dryness of the lake occurred between 7800 and 3000 cal years BP corresponding to the Middle Holocene dry phase. From 3000 cal years BP onwards a gradual increase of the TOC, chlorophyll derivatives and Aulacoseira sp. suggest an increase in the productivity and in water lake level due to the high water flow of the Amazon River and the catchment area as well. The Comprido Lake record indicates that the Late Holocene in this region was characterized by a wetter climate, as also observed in other records of the Amazonian Basin.

  4. Sustainable development, social organization and environment in the Amazonian Area

    International Nuclear Information System (INIS)

    The effects of the development on the environment and the culture in regions like the Amazonian are one of the most dramatic examples that can be in what refers to the physical disappearance of numerous cultures, as well as of their integration to the national society and their rising loss of cultural identity and the devastating consequences that have had the development politicians on the different Amazon ecosystems. The construction of a sustainable development for the region has to evaluate the different societies that have existed and they exist as for the use, handling and exploitation of the natural resources. This paper will be approached this problem in three Amazon societies: the cacique territory, the tribal societies and the societies in formation in the colonization regions. It will be done an analysis and a critic of the development concept and of the consequences that it has had their application so much in the indigenous towns as in the Amazon ecosystems, as well as their relationship with the current characterization of the Amazonian area

  5. Amazonian volcanic activity at the Syrtis volcanic province, Mars

    Science.gov (United States)

    Platz, Thomas; Jodlowski, Piotr; Fawdon, Peter; Michael, Greg; Tanaka, Kenneth

    2014-05-01

    The Syrtis Major volcanic province, including the entire Syrtis Major Planum, is located near the Martian highland/lowland transitional zone west of Isidis Planitia. It covers ≡7.4×105 km2 and contains two low-shield volcanic edifices with N-S elongated calderas named Nili and Meroe Paterae. The estimated thickness of erupted material in the province ranges from approximately 0.5 km to 1.0 km with a total volume of about 1.6-3.2×105 km3 [1]. The timing of volcanic activity in the Syrtis Major volcanic province has been suggested to be restricted to the Hesperian Period [1-4]. In the geological map of Greeley and Guest [2], volcanic material of Syrtis Major was assigned an Hesperian age based on the density of observed craters larger than 5 km in diameter. Using the same crater density range, recent studies of Hiesinger et al. [1] and Tanaka et al. [3] and Tanaka et al. [4] assigned an Early Hesperian and Early to Late Hesperian age, respectively, for the entire province. In this study we mapped lava flows, lava channels, and major lava-flow margins and report model ages for lava-flow formation and caldera segments of Nili and Meroe Paterae. The objective of this ongoing survey is to better understand the eruption frequency of this volcanic province. In total, we mapped 67 lava flows, caldera segments, and intra-crater fillings of which 55 were dated. Crater size-frequency distributions (CSFD) were mapped on HRSC and CTX imagery using CraterTools [5]. CSFDs were analyzed and model ages determined in Craterstats [6] using the production and chronology functions of Ivanov [7] and Hartmann and Neukum [8], respectively. A detailed description of the utilization of the crater-counting technique and its limitations with respect to small-scale mapping is given in Platz et al. [9]. Model ages range between 838 Ma (Middle Amazonian) to 3.6 Ga (Late Hesperian). In our survey, a broad age peak occurs between 2 to 2.6 Ga, continuously declining thereafter. We note that

  6. 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.

  7. Fetal adaptations for viviparity in amphibians.

    Science.gov (United States)

    Wake, Marvalee H

    2015-08-01

    Live-bearing has evolved in all three orders of amphibians--frogs, salamanders, and caecilians. Developing young may be either yolk dependent, or maternal nutrients may be supplied after yolk is resorbed, depending on the species. Among frogs, embryos in two distantly related lineages develop in the skin of the maternal parents' backs; they are born either as advanced larvae or fully metamorphosed froglets, depending on the species. In other frogs, and in salamanders and caecilians, viviparity is intraoviductal; one lineage of salamanders includes species that are yolk dependent and born either as larvae or metamorphs, or that practice cannibalism and are born as metamorphs. Live-bearing caecilians all, so far as is known, exhaust yolk before hatching and mothers provide nutrients during the rest of the relatively long gestation period. The developing young that have maternal nutrition have a number of heterochronic changes, such as precocious development of the feeding apparatus and the gut. Furthermore, several of the fetal adaptations, such as a specialized dentition and a prolonged metamorphosis, are homoplasious and present in members of two or all three of the amphibian orders. At the same time, we know little about the developmental and functional bases for fetal adaptations, and less about the factors that drive their evolution and facilitate their maintenance.

  8. Dietary antioxidants enhance immunocompetence in larval amphibians.

    Science.gov (United States)

    Szuroczki, Dorina; Koprivnikar, Janet; Baker, Robert L

    2016-11-01

    Dietary antioxidants have been shown to confer a variety of benefits through their ability to counter oxidative stress, including increased immunocompetence and reduced susceptibility to both infectious and non-infectious diseases. However, little is known about the effects of dietary antioxidants on immune function in larval amphibians, a group experiencing worldwide declines driven by factors that likely involve altered immunocompetence. We investigated the effects of dietary antioxidants (quercetin, vitamin E, and β-carotene) on two components of the immune system, as well as development and growth. Lithobates pipiens tadpoles fed diets with supplemental β-carotene or vitamin E exhibited an enhanced swelling response as measured with a phytohemagglutinin assay (PHA), but there was no induced antibody response. Effects were often dose-dependent, with higher antioxidant levels generally conferring stronger swelling that possibly corresponds to the innate immune response. Our results indicate that the antioxidant content of the larval amphibian diets not only had a detectable effect on their immune response capability, but also promoted tadpole growth (mass gain), although developmental stage was not affected. Given that many environmental perturbations may cause oxidative stress or reduce immunocompetence, it is critical to understand how nutrition may counter these effects. PMID:27475300

  9. Transcriptome analysis of the Amazonian viper Bothrops atrox venom gland using expressed sequence tags (ESTs).

    Science.gov (United States)

    Neiva, Márcia; Arraes, Fabricio B M; de Souza, Jonso Vieira; Rádis-Baptista, Gandhi; Prieto da Silva, Alvaro R B; Walter, Maria Emilia M T; Brigido, Marcelo de Macedo; Yamane, Tetsuo; López-Lozano, Jorge Luiz; Astolfi-Filho, Spartaco

    2009-03-15

    Bothrops atrox is a highly dangerous pit viper in the Brazilian Amazon region. We produced a global catalogue of gene transcripts to identify the main toxin and other protein families present in the B. atrox venom gland. We prepared a directional cDNA library, from which a set of 610 high quality expressed sequence tags (ESTs) were generated by bioinformatics processing. Our data indicated a predominance of transcripts encoding mainly metalloproteinases (59% of the toxins). The expression pattern of the B. atrox venom was similar to Bothrops insularis, Bothrops jararaca and Bothrops jararacussu in terms of toxin type, although some differences were observed. B. atrox showed a higher amount of the PIII class of metalloproteinases which correlates well with the observed intense hemorrhagic action of its toxin. Also, the PLA2 content was the second highest in this sample compared to the other three Bothrops transcriptomes. To our knowledge, this work is the first transcriptome analysis of an Amazonian rain forest pit viper and it will contribute to the body of knowledge regarding the gene diversity of the venom gland of members of the Bothrops genus. Moreover, our results can be used for future studies with other snake species from the Amazon region to investigate differences in gene patterns or phylogenetic relationships. PMID:19708221

  10. 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.

  11. 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

  12. 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.

    2015-01-01

    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

  13. [Amphibians and reptiles in the swamps dominated by the palm Raphia taedigera (Arecaceae) in northeastern Costa Rica].

    Science.gov (United States)

    Bonilla-Murillo, Fabian; Beneyto, Davinia; Sasa, Mahmood

    2013-09-01

    The herpetofauna that inhabits Caribbean Costa Rica has received considerable attention in the last two decades. This assemblage includes a total of 141 species of reptiles and 95 amphibians mostly distributed in tropical wet and moist lowland forests. While most information available came from primary and secondary forest sites, little is known about the amphibians and reptiles that inhabit more open habitats, such as wetlands and swamps. For instances, swaps dominated by the yolillo palm Raphia taedigera extend through much of the northeastern Caribbean coast of Costa Rica and eastern Nicaragua, but information about the herpetological community that uses such environments remains practically unknown. This situation reflects the little research conducted in such inhospitable environments. Here, we report the results of an intensive survey conducted to assess the herpetological community that inhabit R. taedigera palm-swamps. A total of 14 species of amphibians and 17 of reptiles have been recorded from these swamps. Amphibians and reptiles that inhabit yolillo swamps have wide distributions along much of Middle America and are considered common species throughout their range. In general, yolillo swamps are poor environments for herpetofauna: richness of reptiles and amphibians is almost two times higher in the adjacent forest than in the palm dominated swamps. Furthermore, most species observed in this swamps can be considered habitat generalists that are well adapted to the extreme conditions imposed by the changes in hydroperiods, reduce understory cover, low tree diversity and simple forest architecture of these environments. Despite similarities in the herpetofauna, it is clear that not all forest species use yolillo habitat, a characteristic that is discussed in terms of physical stress driven by the prolonged hydroperiod and reduced leaflitter in the ground, as these features drive habitat structure and herpetofaunal complexity. Our list of species using

  14. Zoonotic diseases associated with reptiles and amphibians: an update.

    Science.gov (United States)

    Mitchell, Mark A

    2011-09-01

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

  15. C dynamics in Amazonian podzols under climate change

    Science.gov (United States)

    Nunan, Naoise; Soro, Andre; Potard, Kevin; Pouteau, Valerie; Montes, Celia; Melphi, Adolpho; Lucas, Yves; Chenu, Claire

    2016-04-01

    It has recently been shown that the C stocks in Amazonian podzols are very large. They are much larger than was previously thought, particularly in the Bh horizon, which has been estimated to contain in excess of 13Pg C for Amazonia alone. It is predicted that the changes in regional climate will result in a drier soil water regime which may affect the C dynamics in these soils that are usually saturated. In order to determine the vulnerability to change of the organic C contained in the Amazonian podzols, a series of incubation experiments were established in which the effects of a number of different factors on microbial decomposition were measured. The direct effect of drier soil water regimes was tested by incubating undisturbed cores from the Bh horizon at a range of matric potentials (saturation to wilting point). Contrary to what is usually found in soils, no significant difference in mineralisation was found among matric potentials, suggesting that other factors control microbial mineralisation of this organic C. The effect of nitrogen additions, of anaerobic conditions and of the addition labile C substrate were also tested on undisturbed cores of the Bh horizon of the podzols. Samples incubated under aerobic conditions produced 3 times more CO2 than samples incubated under anaerobic conditions, whilst samples incubated under aerobic conditions with the addition of N mineralised 6.7 times more CO2 than the anaerobic samples. The addition of labile C did not have a significant effect on C mineralisation, i.e. there was no priming effect. The combined addition of labile C and mineral N did not stimulate C mineralisation more than N additions alone. By extrapolating the differences obtained here to the whole of the Amazonian podzols, it is estimated that changes in conditions which result in an increase in O2 and in N (i.e. changes in vegetation due to increases in dry periods with the establishment of a savanna for example) in the soil will cause the release

  16. Geological control of floristic composition in Amazonian forests

    Science.gov (United States)

    Higgins, Mark A; Ruokolainen, Kalle; Tuomisto, Hanna; Llerena, Nelly; Cardenas, Glenda; Phillips, Oliver L; Vásquez, Rodolfo; Räsänen, Matti

    2011-01-01

    Aim Conservation and land-use planning require accurate maps of patterns in species composition and an understanding of the factors that control them. Substantial doubt exists, however, about the existence and determinants of large-area floristic divisions in Amazonia. Here we ask whether Amazonian forests are partitioned into broad-scale floristic units on the basis of geological formations and their edaphic properties. Location Western and central Amazonia. Methods We used Landsat imagery and Shuttle Radar Topography Mission (SRTM) digital elevation data to identify a possible floristic and geological discontinuity of over 300 km in northern Peru. We then used plant inventories and soil sampling to document changes in species composition and soil properties across this boundary. Data were obtained from 138 sites distributed along more than 450 km of road and river. On the basis of our findings, we used broad-scale Landsat and SRTM mosaics to identify similar patterns across western and central Amazonia. Results The discontinuity identified in Landsat and SRTM data corresponded to a 15-fold change in soil cation concentrations and an almost total change in plant species composition. This discontinuity appears to be caused by the widespread removal of cation-poor surface sediments by river incision to expose cation-rich sediments beneath. Examination of broad-scale Landsat and SRTM mosaics indicated that equivalent processes have generated a north–south discontinuity of over 1500 km in western Brazil. Due to similarities with our study area, we suggest that this discontinuity represents a chemical and ecological limit between western and central Amazonia. Main conclusions Our findings suggest that Amazonian forests are partitioned into large-area units on the basis of geological formations and their edaphic properties. The evolution of these units through geological time may provide a general mechanism for biotic diversification in Amazonia. These compositional

  17. Ingestion of charcoal by the Amazonian earthworm Pontoscolex corethrurus: a potential for tropical soil fertility

    OpenAIRE

    Ponge, Jean-François; Topoliantz, Stéphanie; Ballof, Sylvain; Rossi, Jean-Pierre; Lavelle, Patrick; Betsch, Jean-Marie; Gaucher, Philippe

    2006-01-01

    International audience It is now attested that a large part of the Amazonian rain forest has been cultivated during Pre-Colombian times, using charcoal as an amendment. The incorporation of charcoal to the soil is a starting point for the formation of fertile Amazonian Dark Earths, still selected by Indian people for shifting cultivation. We showed that finely separated charcoal was commonly incorporated in the topsoil by Pontoscolex corethrurus, a tropical earthworm which thrives after bu...

  18. Estimating the global conservation status of more than 15,000 Amazonian tree species

    OpenAIRE

    H. ter Steege; Pitman, NC; Killeen, TJ; Laurance, WF; Peres, CA; Guevara, JE; Salomão, RP; Castilho, CV; Amaral, IL; de Almeida Matos, FD; de Souza Coelho, L; Magnusson, WE; Phillips, OL; de Andrade Lima Filho, D; de Jesus Veiga Carim, M

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened ...

  19. Estimating the global conservation status of more than 15,000 Amazonian tree species.

    OpenAIRE

    H. ter Steege; Pitman, NC; Killeen, TJ; Laurance, WF; Peres, CA; Guevara, JE; Salomão, RP; Castilho, CV; Amaral, IL; de Almeida Matos, FD; de Souza Coelho, L; Magnusson, WE; Phillips, OL; de Andrade Lima Filho, D; de Jesus Veiga Carim, M

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened ...

  20. Fire-mediated dieback and compositional cascade in an Amazonian forest

    OpenAIRE

    Barlow, Jos; Peres, Carlos A.

    2008-01-01

    The only fully coupled land–atmosphere global climate model predicts a widespread dieback of Amazonian forest cover through reduced precipitation. Although these predictions are controversial, the structural and compositional resilience of Amazonian forests may also have been overestimated, as current vegetation models fail to consider the potential role of fire in the degradation of forest ecosystems. We examine forest structure and composition in the Arapiuns River basin in the central Braz...

  1. Extremely long-distance seed dispersal by an overfished Amazonian frugivore

    OpenAIRE

    Anderson, Jill T.; Nuttle, Tim; Saldaña Rojas, Joe S.; Pendergast, Thomas H.; Flecker, Alexander S.

    2011-01-01

    Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, litt...

  2. Impacts of different management systems on the physical quality of an Amazonian Oxisol

    OpenAIRE

    Elaine Maria Silva Guedes; Antonio Rodrigues Fernandes; Herdjania Veras de Lima; Ademar Pereira Serra; José Ribamar Costa; Rafael da Silva Guedes

    2012-01-01

    The physical quality of Amazonian soils is relatively unexplored, due to the unique characteristics of these soils. The index of soil physical quality is a widely accepted measure of the structural quality of soils and has been used to specify the structural quality of some tropical soils, as for example of the Cerrado ecoregion of Brazil. The research objective was to evaluate the physical quality index of an Amazonian dystrophic Oxisol under different management systems. Soils under five ma...

  3. Morphology, morphometry and ultrastructure of the Amazonian manatee (Sirenia: Trichechidae) spermatozoa

    OpenAIRE

    Rodrigo S. Amaral; Carolina M. Lucci; Fernando C. W. Rosas; da Silva, Vera M. F.; Sônia N Báo

    2010-01-01

    This study describes the morphological, morphometric and ultrastructural characteristics of the Amazonian manatee Trichechus inunguis (Natterer, 1883) spermatozoon. The spermatozoa were obtained from a urine sample of an adult T. inunguis kept in captivity. The spermatozoa were analyzed by light and transmission electron microscopy. The head of Amazonian manatee spermatozoa had a flat oval shape and a well distinguishable midpiece. The mean dimensions of the spermatozoa were: head length, 7.4...

  4. Diversidade de Calliphoridae (Insecta: Diptera na base de extração petrolífera da Bacia do Rio Urucu, na Amazônia brasileira Diversity of Calliphoridae flies (Insecta: Diptera in the oil extraction field of Rio Urucu basin, in brasilian Amazonian

    Directory of Open Access Journals (Sweden)

    Maria Cristina Esposito

    2010-09-01

    Full Text Available A diversidade e abundância de dípteros califorídeos de três ambientes (clareira artificial, clareira natural e mata de Porto Urucu/AM foram avaliadas em coletas anuais realizadas em 2004, 2005 e 2006. Ao longo destes três anos foram coletados 2.121 exemplares pertencentes a 14 espécies. As espécies mais abundantes foram Chloroprocta idioidea (Robineau- Desvoidy, Eumesembrinella randa (Walker e Hemilucilia semidiaphana (Rondani. Os habitats de matas e clareiras naturais apresentaram maior abundância de califorídeos quando comparados às clareiras artificiais, com índices de diversidade e equitabilidade também maiores do que em clareiras artificiais, onde a dominância foi mais elevada.The diversity and abundance of blow flies in three environments (anthropic gaps, tree-fall gaps, and primary "terra firme" forest of Porto Urucu/AM were evaluated in annual collects realized in 2004, 2005, and 2006. During these three years were collected 2,121 specimens belonging to 14 species. The most abundant species were Chloroprocta idioidea (Robineau- Desvoidy, Eumesembrinella randa (Walker, and Hemilucilia semidiaphana (Rondani. Primary forests and tree-fall gaps enviroments, showed higher blow flies abundance than anthropic gaps, with diversity and equitability index higher than anthropic gaps, when the dominance value was high.

  5. ASSESSMENT OF THE RISK OF SOLAR ULTRAVIOLET RADIATION TO AMPHIBIANS. II: IN SITU CHARACTERIZATION OF SOLAR ULTRAVIOLET RADIATION IN AMPHIBIAN HABITATS

    Science.gov (United States)

    Ultraviolet B (UVB) radiation has been hypothesized as a potential cause of amphibian population declines and increased incidences of malformations. Realistic studies documenting UV irradiance or dose have rarely been conducted in wetlands used by amphibians. We demonstrate that ...

  6. Biogeography and evolution of Amazonian triatomines (Heteroptera: Reduviidae): implications for Chagas disease surveillance in humid forest ecoregions

    OpenAIRE

    Fernando Abad-Franch; Fernando A Monteiro

    2007-01-01

    An ecological-evolutionary classification of Amazonian triatomines is proposed based on a revision of their main contemporary biogeographical patterns. Truly Amazonian triatomines include the Rhodniini, the Cavernicolini, and perhaps Eratyrus and some Bolboderini. The tribe Rhodniini comprises two major lineages (pictipes and robustus). The former gave rise to trans-Andean (pallescens) and Amazonian (pictipes) species groups, while the latter diversified within Amazonia (robustus group) and r...

  7. Low plant density enhances gene dispersal in the Amazonian understory herb Heliconia acuminata.

    Science.gov (United States)

    Côrtes, Marina C; Uriarte, María; Lemes, Maristerra R; Gribel, Rogério; Kress, W John; Smouse, Peter E; Bruna, Emilio M

    2013-11-01

    In theory, conservation genetics predicts that forest fragmentation will reduce gene dispersal, but in practice, genetic and ecological processes are also dependent on other population characteristics. We used Bayesian genetic analyses to characterize parentage and propagule dispersal in Heliconia acuminata L. C. Richard (Heliconiaceae), a common Amazonian understory plant that is pollinated and dispersed by birds. We studied these processes in two continuous forest sites and three 1-ha fragments in Brazil's Biological Dynamics of Forest Fragments Project. These sites showed variation in the density of H. acuminata. Ten microsatellite markers were used to genotype flowering adults and seedling recruits and to quantify realized pollen and seed dispersal distances, immigration of propagules from outside populations, and reproductive dominance among parents. We tested whether gene dispersal is more dependent on fragmentation or density of reproductive plants. Low plant densities were associated with elevated immigration rates and greater propagule dispersal distances. Reproductive dominance among inside-plot parents was higher for low-density than for high-density populations. Elevated local flower and fruit availability is probably leading to spatially more proximal bird foraging and propagule dispersal in areas with high density of reproductive plants. Nevertheless, genetic diversity, inbreeding coefficients and fine-scale spatial genetic structure were similar across populations, despite differences in gene dispersal. This result may indicate that the opposing processes of longer dispersal events in low-density populations vs. higher diversity of contributing parents in high-density populations balance the resulting genetic outcomes and prevent genetic erosion in small populations and fragments.

  8. Low plant density enhances gene dispersal in the Amazonian understory herb Heliconia acuminata.

    Science.gov (United States)

    Côrtes, Marina C; Uriarte, María; Lemes, Maristerra R; Gribel, Rogério; Kress, W John; Smouse, Peter E; Bruna, Emilio M

    2013-11-01

    In theory, conservation genetics predicts that forest fragmentation will reduce gene dispersal, but in practice, genetic and ecological processes are also dependent on other population characteristics. We used Bayesian genetic analyses to characterize parentage and propagule dispersal in Heliconia acuminata L. C. Richard (Heliconiaceae), a common Amazonian understory plant that is pollinated and dispersed by birds. We studied these processes in two continuous forest sites and three 1-ha fragments in Brazil's Biological Dynamics of Forest Fragments Project. These sites showed variation in the density of H. acuminata. Ten microsatellite markers were used to genotype flowering adults and seedling recruits and to quantify realized pollen and seed dispersal distances, immigration of propagules from outside populations, and reproductive dominance among parents. We tested whether gene dispersal is more dependent on fragmentation or density of reproductive plants. Low plant densities were associated with elevated immigration rates and greater propagule dispersal distances. Reproductive dominance among inside-plot parents was higher for low-density than for high-density populations. Elevated local flower and fruit availability is probably leading to spatially more proximal bird foraging and propagule dispersal in areas with high density of reproductive plants. Nevertheless, genetic diversity, inbreeding coefficients and fine-scale spatial genetic structure were similar across populations, despite differences in gene dispersal. This result may indicate that the opposing processes of longer dispersal events in low-density populations vs. higher diversity of contributing parents in high-density populations balance the resulting genetic outcomes and prevent genetic erosion in small populations and fragments. PMID:24730040

  9. Lipase Activity among Bacteria Isolated from Amazonian Soils.

    Science.gov (United States)

    Willerding, André Luis; de Oliveira, Luiz Antonio; Moreira, Francisco Wesen; Germano, Mariana Gomes; Chagas, Aloísio Freitas

    2011-01-01

    The objective of this study was to select lipase-producing bacteria collected from different counties of the Amazon region. Of the 440 bacteria strains, 181 were selected for the lipase assay in qualitative tests at Petri dishes, being 75 (41%) lipase positive. The enzymatic index was determined during fifteen days at different temperatures (30°, 35°, 40°, and 45°C). The highest lipase activity was observed within 72 hours at 30°C. Twelve bacteria strains presented an index equal to or greater than the standard used like reference, demonstrating the potential of microbial resource. After the bioassay in Petri dishes, the selected bacteria strains were analyzed in quantitative tests on p-nitrophenyl palmitate (p-NPP). A group of the strains was selected for other phases of study with the use in oleaginous substrates of the Amazonian flora, aiming for the application in processes like oil biotransformation. PMID:22007294

  10. Lipase Activity among Bacteria Isolated from Amazonian Soils

    Directory of Open Access Journals (Sweden)

    André Luis Willerding

    2011-01-01

    Full Text Available The objective of this study was to select lipase-producing bacteria collected from different counties of the Amazon region. Of the 440 bacteria strains, 181 were selected for the lipase assay in qualitative tests at Petri dishes, being 75 (41% lipase positive. The enzymatic index was determined during fifteen days at different temperatures (30°, 35°, 40°, and 45°C. The highest lipase activity was observed within 72 hours at 30°C. Twelve bacteria strains presented an index equal to or greater than the standard used like reference, demonstrating the potential of microbial resource. After the bioassay in Petri dishes, the selected bacteria strains were analyzed in quantitative tests on p-nitrophenyl palmitate (p-NPP. A group of the strains was selected for other phases of study with the use in oleaginous substrates of the Amazonian flora, aiming for the application in processes like oil biotransformation.

  11. Model gives a 3-month warning of Amazonian forest fires

    Science.gov (United States)

    Schultz, Colin

    2011-08-01

    The widespread drought suffered by the Amazon rain forest in the summer of 2005 was heralded at the time as the drought of the century. Because of the dehydrated conditions, supplemented by slash and burn agricultural practices, the drought led to widespread forest fires throughout the western Amazon, a portion of the rain forest usually too lush to support spreading wildfires. Only 5 years later, the 2005 season was outdone by even more widespread drought, with fires decimating more than 3000 square kilometers of western Amazonian rain forest. Blame for the wildfires has been consistently laid on deforestation and agricultural practices, but a convincing climatological explanation exists as well. (Geophysical Research Letters, doi:10.1029/2011GL047392, 2011)

  12. Large-scale degradation of Amazonian freshwater ecosystems.

    Science.gov (United States)

    Castello, Leandro; Macedo, Marcia N

    2016-03-01

    Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework

  13. Large-scale degradation of Amazonian freshwater ecosystems.

    Science.gov (United States)

    Castello, Leandro; Macedo, Marcia N

    2016-03-01

    Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework

  14. Fish Springs NWR mammal, fish, amphibian, and reptile list

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The following is a species list for mammals, fishes, amphibians, and reptiles found on or adjacent to Fish Springs National Wildlife Refuge, as of October, 1996.

  15. 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....

  16. 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.

  17. Sperm motility of externally fertilizing fish and amphibians.

    Science.gov (United States)

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

    2015-01-01

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

  18. 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.

  19. 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....

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

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2000, the FWS's Environmental Contaminants Program (currently Environmental Quality Program) received funding as part of the Department of Interior's Amphibian...

  1. Scientists urge enforcement of an amphibian conservation plan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ A group of CAS biologists recently lodged an appeal, calling for initiating a national action plan as soon as possible to protect the amphibian species now struggling for their survival throughout the country.

  2. Checklist of Helminth parasites of Amphibians from South America.

    Science.gov (United States)

    Campião, Karla Magalhães; Morais, Drausio Honorio; Dias, Olívia Tavares; Aguiar, Aline; Toledo, Gislayne De Melo; Tavares, Luiz Eduardo Roland; Da Silva, Reinaldo José

    2014-07-30

    Parasitological studies on helminths of amphibians in South America have increased in the past few years. Here, we present a list with summarized data published on helminths of South American amphibians from 1925 to 2012, including a list of helminth parasites, host species, and geographic records. We found 194 reports of helminths parasitizing 185 amphibian species from eleven countries: Argentina, Brazil, Chile, Colombia, Equador, French Guyana, Guyana, Paraguay, Peru, Uruguay and Venezuela. Helminth biodiversity includes 278 parasite species of the groups Acanthocephala, Nematoda, Cestoda, Monogenea and Trematoda. A list of helminth parasite species per host, and references are also presented. This contribution aims to document the biodiversity of helminth parasites in South American amphibians, as well as identify gaps in our knowledge, which in turn may guide subsequent studies. 

  3. 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...

  4. Invasive and introduced reptiles and amphibians: Chapter 28

    Science.gov (United States)

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

    2014-01-01

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

  5. 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 ...

  6. FACTORS IMPLICATED IN AMPHIBIAN POPULATION DECLINES IN THE UNITED STATES

    Science.gov (United States)

    This study identified the factors responsible for the decline of native amphibians in the U.S. The type of land use, the introduction of exotic animal species, and chemical contamination were identified as the most likely causes of decline.

  7. 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.

  8. Update of reptile and amphibian lists Kern NWR complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document includes a list of reptiles and amphibians found at Kern NWR, and lists brief species accounts for rare sightings/species. Attached are updated lists...

  9. 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

  10. 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.

  11. 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 FWS's Environmental Contaminants Program (currently Environmental Quality Program) received funding as part of the Department of Interior's Amphibian...

  12. 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 FWS's Environmental Contaminants Program (currently Environmental Quality Program) received funding as part of the Department of Interior's Amphibian...

  13. Amphibian chytrid fungus Batrachochytrium dendrobatidis in Cusuco National Park, Honduras.

    Science.gov (United States)

    Kolby, Jonathan E; Padgett-Flohr, Gretchen E; Field, Richard

    2010-11-01

    Amphibian population declines in Honduras have long been attributed to habitat degradation and pollution, but an increasing number of declines are now being observed from within the boundaries of national parks in pristine montane environments. The amphibian chytrid fungus Batrachochytrium dendrobatidis has been implicated in these declines and was recently documented in Honduras from samples collected in Pico Bonito National Park in 2003. This report now confirms Cusuco National Park, a protected cloud forest reserve with reported amphibian declines, to be the second known site of infection for Honduras. B. dendrobatidis infection was detected in 5 amphibian species: Craugastor rostralis, Duellmanohyla soralia, Lithobates maculata, Plectrohyla dasypus, and Ptychohyla hypomykter. D. soralia, P. dasypus, and P. hypomykter are listed as critically endangered in the IUCN Red List of Threatened Species and have severely fragmented or restricted distributions. Further investigations are necessary to determine whether observed infection levels indicate an active B. dendrobatidis epizootic with the potential to cause further population declines and extinction.

  14. 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

  15. Resistance to cancer in amphibians: a role for apoptosis?

    Science.gov (United States)

    Ruben, Laurens N; Johnson, Rachel O; Clothier, Richard H; Balls, Michael

    2013-07-01

    The rarity of spontaneous cancer in amphibians, and the difficulty of inducing cancer in these lower vertebrates, suggest that they possess an effective system for resistance to the development of cancer. The first part of this narrative presents evidence for cancer resistance in amphibians, and then a variety of studies designed to help understand the physiological basis for this resistance are reviewed. Here, our emphasis is on evidence with regard to the role that apoptosis might play.

  16. 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...

  17. 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...

  18. 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.

  19. Why amphibians are more sensitive than mammals to xenobiotics.

    Science.gov (United States)

    Quaranta, Angelo; Bellantuono, Vito; Cassano, Giuseppe; Lippe, Claudio

    2009-11-04

    Dramatic declines in amphibian populations have been described all over the world since the 1980s. The evidence that the sensitivity to environmental threats is greater in amphibians than in mammals has been generally linked to the observation that amphibians are characterized by a rather permeable skin. Nevertheless, a numerical comparison of data of percutaneous (through the skin) passage between amphibians and mammals is lacking. Therefore, in this investigation we have measured the percutaneous passage of two test molecules (mannitol and antipyrine) and three heavily used herbicides (atrazine, paraquat and glyphosate) in the skin of the frog Rana esculenta (amphibians) and of the pig ear (mammals), by using the same experimental protocol and a simple apparatus which minimizes the edge effect, occurring when the tissue is clamped in the usually used experimental device.The percutaneous passage (P) of each substance is much greater in frog than in pig. LogP is linearly related to logKow (logarithm of the octanol-water partition coefficient). The measured P value of atrazine was about 134 times larger than that of glyphosate in frog skin, but only 12 times in pig ear skin. The FoD value (Pfrog/Ppig) was 302 for atrazine, 120 for antipyrine, 66 for mannitol, 29 for paraquat, and 26 for glyphosate.The differences in structure and composition of the skin between amphibians and mammals are discussed.

  20. Why amphibians are more sensitive than mammals to xenobiotics.

    Directory of Open Access Journals (Sweden)

    Angelo Quaranta

    Full Text Available Dramatic declines in amphibian populations have been described all over the world since the 1980s. The evidence that the sensitivity to environmental threats is greater in amphibians than in mammals has been generally linked to the observation that amphibians are characterized by a rather permeable skin. Nevertheless, a numerical comparison of data of percutaneous (through the skin passage between amphibians and mammals is lacking. Therefore, in this investigation we have measured the percutaneous passage of two test molecules (mannitol and antipyrine and three heavily used herbicides (atrazine, paraquat and glyphosate in the skin of the frog Rana esculenta (amphibians and of the pig ear (mammals, by using the same experimental protocol and a simple apparatus which minimizes the edge effect, occurring when the tissue is clamped in the usually used experimental device.The percutaneous passage (P of each substance is much greater in frog than in pig. LogP is linearly related to logKow (logarithm of the octanol-water partition coefficient. The measured P value of atrazine was about 134 times larger than that of glyphosate in frog skin, but only 12 times in pig ear skin. The FoD value (Pfrog/Ppig was 302 for atrazine, 120 for antipyrine, 66 for mannitol, 29 for paraquat, and 26 for glyphosate.The differences in structure and composition of the skin between amphibians and mammals are discussed.

  1. Global amphibian declines: perspectives from the United States and beyond

    Science.gov (United States)

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

    2011-01-01

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

  2. Tropical amphibian populations experience higher disease risk in natural habitats.

    Science.gov (United States)

    Becker, C Guilherme; Zamudio, Kelly R

    2011-06-14

    Habitat loss and disease are main drivers of global amphibian declines, yet the interaction between them remains largely unexplored. Here we show that paradoxically, habitat loss is negatively associated with occurrence, prevalence, and infection intensity of the chytrid fungus Batrachochytrium dendrobatidis (Bd) in amphibian populations in the tropics. At a large spatial scale, increased habitat loss predicted lower disease risk in amphibian populations across Costa Rica and eastern Australia, even after jointly considering the effect of potential biotic and abiotic correlates. Lower host-species richness and suboptimal microclimates for Bd in disturbed habitats are potential mechanisms underlying this pattern. Furthermore, we found that anthropogenic deforestation practices biased to lowlands and natural vegetation remaining in inaccessible highlands explain increased Bd occurrence at higher elevations. At a smaller spatial scale, holding constant elevation, latitude, and macroclimate, we also found a negative relationship between habitat loss, and both Bd prevalence and infection intensity in frog populations in two landscapes of the Brazilian Atlantic Forest. Our results indicate that amphibians will be disproportionately affected by emerging diseases in pristine environments, and that, paradoxically, disturbed habitats may act as shelters from disease, but only for the very few species that can tolerate deforestation. Thus, tropical amphibian faunas are threatened both by destruction of natural habitats as well as increased disease in pristine forests. To curb further extinctions and develop effective mitigation and restoration programs we must look to interactions between habitat loss and disease, the two main factors at the root of global amphibian declines.

  3. Effects of urbanization on the distribution and abundance of amphibians and invasive species in southern California streams

    Science.gov (United States)

    Riley, S.P.D.; Busteed, G.T.; Kats, L.B.; Vandergon, T.L.; Lee, L.F.S.; Dagit, R.G.; Kerby, J.L.; Fisher, R.N.; Sauvajot, R.M.

    2005-01-01

    Urbanization negatively affects natural ecosystems in many ways, and aquatic systems in particular. Urbanization is also cited as one of the potential contributors to recent dramatic declines in amphibian populations. From 2000 to 2002 we determined the distribution and abundance of native amphibians and exotic predators and characterized stream habitat and invertebratecommunities in 35 streams in an urbanized landscape north of Los Angeles (U.S.A.). We measured watershed development as the percentage of area within each watershed occupied by urban land uses. Streams in more developed watersheds often had exotic crayfish (Procambarus clarkii) and fish, and had fewer native species such as California newts (Taricha torosa) and California treefrogs (Hyla cadaverina). These effects seemed particularly evident above 8% development, a result coincident with other urban stream studies that show negative impacts beginning at 10-15% urbanization. For Pacific treefrogs (H. regilla), the most widespread native amphibian, abundance was lower in the presence of exotic crayfish, although direct urbanization effects were not found. Benthic macroinvertebrate communities were also less diverse in urban streams, especially for sensitive species. Faunal community changes in urban streams may be related to changes in physical stream habitat, such as fewer pool and more run habitats and increased water depth and flow, leading to more permanent streams. Variation in stream permanence was particularly evident in 2002, a dry year when many natural streams were dry but urban streams were relatively unchanged. Urbanization has significantly altered stream habitat in this region and may enhance invasion by exotic species and negatively affect diversity and abundance of native amphibians. ??2005 Society for Conservation Biology.

  4. 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...

  5. Determinants of beta diversity: the relative importance of environmental and spatial processes in structuring phytoplankton communities in an Amazonian floodplain Determinantes da diversidade beta: a importância relativa de processos ambientais e espaciais na estrutura de comunidades fitoplanctônicas de uma planície de inundação amazônica

    Directory of Open Access Journals (Sweden)

    Ina de Souza Nogueira

    2010-09-01

    Full Text Available AIM: Beta diversity is defined as the change in species composition along environmental gradients, and in the present study, we investigated the influence of local (i.e., environmental and regional (i.e., dispersal factors in community structure. The aims of this study were to evaluate the beta diversity of phytoplankton communities in the Curuaí floodplain and to determine the relative importance of environmental and spatial processes in shaping phytoplankton community structure; METHOD: The phytoplankton communities were sampled in 16 lakes of the Curuaí floodplain (Amazon Basin during high-water periods in 2002 and 2003. We used partial redundancy analysis (pRDA to evaluate the pure effect of environmental (six variables and spatial (spatial filter variability on phytoplankton community composition; RESULTS: There were 156 taxa recorded in the two study years, including 122 algae species in 2002 and 66 algae species in 2003. The beta diversity that we measured (βSIM index was 0.889 in 2002 and 0.789 in 2003. The partitioning variation demonstrated that the majority of variation in phytoplankton community structure was not significantly explained by pure environmental and pure spatial components. However, environmental variables presented a larger coefficient of determination than the spatial variable; CONCLUSION: Other factors than those we measured in this study, such as local variables (i.e., biotic interactions, hydrology, etc. and stochastic events, affected the absence of significant results in our data. Therefore, we suggest that additional variables, such as biological interactions and other local factors, should be considered in this type of analysis to increase its explanatory power for understanding the variation of diversity in these communities.OBJETIVO: A diversidade beta é definida como as mudanças na composição de espécies ao longo de um gradiente ambiental, e atualmente, ecólogos têm investigado a influência de

  6. A checklist of the reptiles and amphibians found in protected areas along the South African Wild Coast, with notes on conservation implications

    Directory of Open Access Journals (Sweden)

    Jan A. Venter

    2015-03-01

    Full Text Available We surveyed six protected areas along the Wild Coast of the Eastern Cape, South Africa, to determine general herpetofaunal diversity as well as the representation of species of special conservation concern. Visual encounter survey methods and standard Y-shape trap arrays were used to conduct surveys from 2011 to 2013. A total of 59 species (22 amphibians and 37 reptiles were recorded. A number of previously unknown populations of threatened species and one potential novel species were discovered in these protected areas, and the known ranges of several other species were extended. A total of 243 quarter-degree grid-cell unit records were documented, of which 90 (23% amphibians and 50% reptiles represented the first records for the area. Amphibian and reptile diversity increased along the coast and a number of species of conservation concern were well represented in current protected areas. Our study provides a comprehensive amphibian and reptile checklist for an under-sampled region and highlights the importance of baseline data for improving conservation management.Conservation implications: Small protected areas play an important role in conserving a number of threatened herpetofaunal species along the Wild Coast. The region is currently under significant and increasing pressure from anthropogenic-induced environmental degradation, which affects biodiversity and subsequently the local inhabitants. The information presented here represents an important baseline for future conservation management.

  7. 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 ...

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

    Science.gov (United States)

    Seigel, Richard A.; Dodd, C. Kenneth

    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.

  9. Developments in amphibian captive breeding and reintroduction programs.

    Science.gov (United States)

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

    2016-04-01

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

  10. Atlantic forcing of Amazonian climates in the last ice age

    Science.gov (United States)

    Bush, M. B.; Mosblech, N.; Valencia, B. G.; Hodell, D. A.; Gosling, W. D.; Van Calsteren, P. W.; Thomas, L. E.; Curtis, J. H.

    2011-12-01

    An absence of study sites means that the relative influence of orbitally driven presession cycles and millenial scale variability upon ice-age Amazonian precipitation is unknown. Here we present a continuous isotopic (δO18 and C13) record spanning the period from ~93-8 ka, from the aseasonal forests of Amazonian Ecuador. The variability in δO18 depletion is probably related to the relative strength of evapotranspired moisture (less depleted) and tropical Atlantic moisture carried across the basin by the South American Low Level Jet (more depleted). Times of strengthened South American Low Level Jet probably correspond to increased overall moisture availability and hence elevated precipitation. The occurrence of markedly depleted δO18 signatures during Heinrich events suggests a strong influence of the Atlantic Ocean on this system, and that these northern hemispheric stadials induced wet episodes in western Amazonia. Weakening of the Atlantic Meridional Overturning Circulation (AMOC) has been suggested to strengthen the South American Low Level Jet. The isotopic records reveal strong cohesion with previously published records from southern Brazil. A precessional influence amplifies the north Atlantic signal between c. 93 ka and 50 ka. However, after c. 50 ka the precessional signal weakens, perhaps sugesting that at a critical size the Laurentide ice mass exerted a strong influence on Neotropical climates suppressing the weaker forcing associated with precession. Contrary to long-standing expectation, the Last Glacial Maximum (21 ± 2 ka) does not stand out as time of aridity in this record. However, between c. 35 ka and 18 ka there is a drift toward less depleted rainfall. One hypothesis to account for this observation is that the climate was becoming more seasonal as the Intertropical Convergence Zone (ITCZ) formed further south than its modern location. The resulting weakened influence of the South American Summer Monsoon (SASM) would probably reduce wet

  11. Dynamics of carbon, biomass, and structure in two Amazonian forests

    Science.gov (United States)

    Pyle, Elizabeth Hammond; Santoni, Gregory W.; Nascimento, Henrique E. M.; Hutyra, Lucy R.; Vieira, Simone; Curran, Daniel J.; van Haren, Joost; Saleska, Scott R.; Chow, V. Y.; Carmago, Plinio B.; Laurance, William F.; Wofsy, Steven C.

    2008-11-01

    Amazon forests are potentially globally significant sources or sinks for atmospheric carbon dioxide. In this study, we characterize the spatial trends in carbon storage and fluxes in both live and dead biomass (necromass) in two Amazonian forests, the Biological Dynamic of Forest Fragments Project (BDFFP), near Manaus, Amazonas, and the Tapajós National Forest (TNF) near Santarém, Pará. We assessed coarse woody debris (CWD) stocks, tree growth, mortality, and recruitment in ground-based plots distributed across the terra firme forest at both sites. Carbon dynamics were similar within each site, but differed significantly between the sites. The BDFFP and the TNF held comparable live biomass (167 +/- 7.6 MgC.ha-1 versus 149 +/- 6.0 MgC.ha-1, respectively), but stocks of CWD were 2.5 times larger at TNF (16.2 +/- 1.5 MgC.ha-1 at BDFFP, versus 40.1 +/- 3.9 MgC.ha-1 at TNF). A model of current forest dynamics suggests that the BDFFP was close to carbon balance, and its size class structure approximated a steady state. The TNF, by contrast, showed rapid carbon accrual to live biomass (3.24 +/- 0.22 MgC.ha-1.a-1 in TNF, 2.59 +/- 0.16 MgC.ha-1.a-1 in BDFFP), which was more than offset by losses from large stocks of CWD, as well as ongoing shifts of biomass among size classes. This pattern in the TNF suggests recovery from a significant disturbance. The net loss of carbon from the TNF will likely last 10-15 years after the initial disturbance (controlled by the rate of decay of coarse woody debris), followed by uptake of carbon as the forest size class structure and composition continue to shift. The frequency and longevity of forests showing such disequilibruim dynamics within the larger matrix of the Amazon remains an essential question to understanding Amazonian carbon balance.

  12. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.

    Directory of Open Access Journals (Sweden)

    Rodrigo Marciente

    Full Text Available Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.

  13. Frugivory in Canopy Plants in a Western Amazonian Forest: Dispersal Systems, Phylogenetic Ensembles and Keystone Plants.

    Directory of Open Access Journals (Sweden)

    Pablo R Stevenson

    Full Text Available Frugivory is a widespread mutualistic interaction in which frugivores obtain nutritional resources while favoring plant recruitment through their seed dispersal services. Nonetheless, how these complex interactions are organized in diverse communities, such as tropical forests, is not fully understood. In this study we evaluated the existence of plant-frugivore sub-assemblages and their phylogenetic organization in an undisturbed western Amazonian forest in Colombia. We also explored for potential keystone plants, based on network analyses and an estimate of the amount of fruit going from plants to frugivores. We carried out diurnal observations on 73 canopy plant species during a period of two years. During focal tree sampling, we recorded frugivore identity, the duration of each individual visit, and feeding rates. We did not find support for the existence of sub assemblages, such as specialized vs. generalized dispersal systems. Visitation rates on the vast majority of canopy species were associated with the relative abundance of frugivores, in which ateline monkeys (i.e. Lagothrix and Ateles played the most important roles. All fruiting plants were visited by a variety of frugivores and the phylogenetic assemblage was random in more than 67% of the cases. In cases of aggregation, the plant species were consumed by only primates or only birds, and filters were associated with fruit protection and likely chemical content. Plants suggested as keystone species based on the amount of pulp going from plants to frugivores differ from those suggested based on network approaches. Our results suggest that in tropical forests most tree-frugivore interactions are generalized, and abundance should be taken into account when assessing the most important plants for frugivores.

  14. Frugivory in Canopy Plants in a Western Amazonian Forest: Dispersal Systems, Phylogenetic Ensembles and Keystone Plants.

    Science.gov (United States)

    Stevenson, Pablo R; Link, Andrés; González-Caro, Sebastian; Torres-Jiménez, María Fernanda

    2015-01-01

    Frugivory is a widespread mutualistic interaction in which frugivores obtain nutritional resources while favoring plant recruitment through their seed dispersal services. Nonetheless, how these complex interactions are organized in diverse communities, such as tropical forests, is not fully understood. In this study we evaluated the existence of plant-frugivore sub-assemblages and their phylogenetic organization in an undisturbed western Amazonian forest in Colombia. We also explored for potential keystone plants, based on network analyses and an estimate of the amount of fruit going from plants to frugivores. We carried out diurnal observations on 73 canopy plant species during a period of two years. During focal tree sampling, we recorded frugivore identity, the duration of each individual visit, and feeding rates. We did not find support for the existence of sub assemblages, such as specialized vs. generalized dispersal systems. Visitation rates on the vast majority of canopy species were associated with the relative abundance of frugivores, in which ateline monkeys (i.e. Lagothrix and Ateles) played the most important roles. All fruiting plants were visited by a variety of frugivores and the phylogenetic assemblage was random in more than 67% of the cases. In cases of aggregation, the plant species were consumed by only primates or only birds, and filters were associated with fruit protection and likely chemical content. Plants suggested as keystone species based on the amount of pulp going from plants to frugivores differ from those suggested based on network approaches. Our results suggest that in tropical forests most tree-frugivore interactions are generalized, and abundance should be taken into account when assessing the most important plants for frugivores.

  15. Asymmetric dispersal and colonization success of Amazonian plant-ants queens.

    Directory of Open Access Journals (Sweden)

    Emilio M Bruna

    Full Text Available BACKGROUND: The dispersal ability of queens is central to understanding ant life-history evolution, and plays a fundamental role in ant population and community dynamics, the maintenance of genetic diversity, and the spread of invasive ants. In tropical ecosystems, species from over 40 genera of ants establish colonies in the stems, hollow thorns, or leaf pouches of specialized plants. However, little is known about the relative dispersal ability of queens competing for access to the same host plants. METHODOLOGY/PRINCIPAL FINDINGS: We used empirical data and inverse modeling--a technique developed by plant ecologists to model seed dispersal--to quantify and compare the dispersal kernels of queens from three Amazonian ant species that compete for access to host-plants. We found that the modal colonization distance of queens varied 8-fold, with the generalist ant species (Crematogaster laevis having a greater modal distance than two specialists (Pheidole minutula, Azteca sp. that use the same host-plants. However, our results also suggest that queens of Azteca sp. have maximal distances that are four-sixteen times greater than those of its competitors. CONCLUSIONS/SIGNIFICANCE: We found large differences between ant species in both the modal and maximal distance ant queens disperse to find vacant seedlings used to found new colonies. These differences could result from interspecific differences in queen body size, and hence wing musculature, or because queens differ in their ability to identify potential host plants while in flight. Our results provide support for one of the necessary conditions underlying several of the hypothesized mechanisms promoting coexistence in tropical plant-ants. They also suggest that for some ant species limited dispersal capability could pose a significant barrier to the rescue of populations in isolated forest fragments. Finally, we demonstrate that inverse models parameterized with field data are an excellent means

  16. Incentive or Habit Learning in Amphibians?

    Science.gov (United States)

    Muzio, Rubén N.; Pistone Creydt, Virginia; Iurman, Mariana; Rinaldi, Mauro A.; Sirani, Bruno; Papini, Mauricio R.

    2011-01-01

    Toads (Rhinella arenarum) received training with a novel incentive procedure involving access to solutions of different NaCl concentrations. In Experiment 1, instrumental behavior and weight variation data confirmed that such solutions yield incentive values ranging from appetitive (deionized water, DW, leading to weight gain), to neutral (300 mM slightly hypertonic solution, leading to no net weight gain or loss), and aversive (800 mM highly hypertonic solution leading to weight loss). In Experiment 2, a downshift from DW to a 300 mM solution or an upshift from a 300 mM solution to DW led to a gradual adjustment in instrumental behavior. In Experiment 3, extinction was similar after acquisition with access to only DW or with a random mixture of DW and 300 mM. In Experiment 4, a downshift from DW to 225, 212, or 200 mM solutions led again to gradual adjustments. These findings add to a growing body of comparative evidence suggesting that amphibians adjust to incentive shifts on the basis of habit formation and reorganization. PMID:22087217

  17. Incentive or habit learning in amphibians?

    Directory of Open Access Journals (Sweden)

    Rubén N Muzio

    Full Text Available Toads (Rhinella arenarum received training with a novel incentive procedure involving access to solutions of different NaCl concentrations. In Experiment 1, instrumental behavior and weight variation data confirmed that such solutions yield incentive values ranging from appetitive (deionized water, DW, leading to weight gain, to neutral (300 mM slightly hypertonic solution, leading to no net weight gain or loss, and aversive (800 mM highly hypertonic solution leading to weight loss. In Experiment 2, a downshift from DW to a 300 mM solution or an upshift from a 300 mM solution to DW led to a gradual adjustment in instrumental behavior. In Experiment 3, extinction was similar after acquisition with access to only DW or with a random mixture of DW and 300 mM. In Experiment 4, a downshift from DW to 225, 212, or 200 mM solutions led again to gradual adjustments. These findings add to a growing body of comparative evidence suggesting that amphibians adjust to incentive shifts on the basis of habit formation and reorganization.

  18. Neotropical Amphibian Declines Affect Stream Ecosystem Properties

    Science.gov (United States)

    Connelly, S.; Pringle, C. M.; Bixby, R. J.; Whiles, M. R.; Lips, K. R.; Brenes, R.; Colon-Gaud, J. C.; Kilham, S.; Hunte-Brown, M.

    2005-05-01

    Global declines of amphibians are well documented, yet effects of these dramatic losses on ecosystem structure and function are poorly understood. As part of a larger collaborative project, we compared two upland Panamanian streams. Both streams are biologically and geologically similar; however, one stream (Fortuna) has recently experienced almost complete extirpation of stream-dwelling frogs, while the other (Cope) still has intact populations. We experimentally excluded tadpoles from localized areas in each stream. We then compared chlorophyll a, algal community composition, ash-free dry mass (AFDM), inorganic matter, and insect assemblages in control and exclusion areas. Additionally, we sampled the natural substrate of both streams monthly for chlorophyll a, algal community composition, AFDM, and inorganic matter. At Cope, chlorophyll a, AFDM, and inorganic matter were greater in areas where tadpoles were excluded than in their presence. Numbers of dominant algal species (e.g., Nupela praecipua and Eunotia siolii) were greater in the exclusion versus control treatments. Monthly sampling of natural substrate indicated higher chlorophyll a and AFDM at Cope compared to Fortuna. Our data suggest that stream-dwelling anuran larvae have significant impacts on algal communities. These results also have implications for predicting the relevance of short-term experimental manipulations to long-term, whole-stream processes.

  19. Investigating the Influence of Environmental Factors on Pesticide Exposure in Amphibians

    Science.gov (United States)

    Environmental factors such as temporal weather patterns and soil characterization coupled with pesticide application rates are known to influence exposure and subsequent absorption of these compounds in amphibians. Amphibians are a unique class of vertebrates due to their varied ...

  20. 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.; 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.

  1. Conserved structure of amphibian T-cell antigen receptor beta chain.

    Science.gov (United States)

    Fellah, J S; Kerfourn, F; Guillet, F; Charlemagne, J

    1993-07-15

    All jawed vertebrates possess well-differentiated thymuses and elicit T-cell-like cell-mediated responses; however, no surface T-cell receptor (TCR) molecules or TCR genes have been identified in ectothermic vertebrate species. Here we describe cDNA clones from an amphibian species, Ambystoma mexicanum (the Mexican axolotl), that have sequences highly homologous to the avian and mammalian TCR beta chains. The cloned amphibian beta chain variable region (V beta) shares most of the structural characteristics with the more evolved vertebrate V beta and presents approximately 56% amino acid identities with the murine V beta 14 and human V beta 18 families. The two different cloned axolotl beta chain joining regions (J beta) were found to have conserved all the invariant mammalian J beta residues, and in addition, the presence of a conserved glycine at the V beta-J beta junction suggests the existence of diversity elements. The extracellular domains of the two axolotl beta chain constant region isotypes C beta 1 and C beta 2 show an impressively high degree of identity, thus suggesting that a very efficient mechanism of gene correction has been in operation to preserve this structure at least from the early tetrapod evolution. The transmembrane axolotl C beta domains have been less well conserved when compared to the mammalian C beta but they do maintain the lysine residue that is thought to be involved in the charged interaction between the TCR alpha beta heterodimer and the CD3 complex. PMID:8341702

  2. Amphibian metamorphosis as a model for studying the developmental actions of thyroid hormone

    Institute of Scientific and Technical Information of China (English)

    TATAJAMSHENR

    1998-01-01

    The thyroid hormones L-thyroxine and triiodo-Lthyronine have profound effects on postenbryonic development of most vertebrates.Analysis of their action in mammals is vitiated by the exposure of the developing foetus to a number of maternal factors which do not allow one to specifically define the role of thyroid hormone (TH) or that of other hormones and factors that modulate its action.Amphibian metamorphosis is obligatorily dependent on TH which can initiate all the diverse physiological manifestations of this postembryonic developmental process(morphogenesis,cell death,re-structuring,etc.) in free-living embryos and larvas of most anurans.This article will first describe the salient features of metamorphosis and its control by TH and other hormones.Emphasis will be laid on the key role played by TH receptor (TR),in particular the phenomenon of TR gene autoinduction,in initiating the developmental action of TH.Finally,it will be argued that the findings on the control of amphibian metamorphosis enhance our understanding of the regulation of postembryonic development by TH in other vertebrate species.

  3. Causes of mortality in anuran amphibians from an ex situ survival assurance colony in Panama.

    Science.gov (United States)

    Pessier, Allan P; Baitchman, Eric J; Crump, Paul; Wilson, Brad; Griffith, Edgardo; Ross, Heidi

    2014-01-01

    The success of ex situ survival assurance populations as tools for amphibian conservation depends on the health and reproductive success of founder populations. Necropsy examination and histopathology of animals that die in assurance populations are useful for the identification of population-limiting disease problems and can help to direct applied research efforts in areas such as amphibian husbandry and nutrition. This study reviewed postmortem findings in 167 frogs from 13 species that died in a large Panamanian rescue and survival assurance population between 2006 and 2011. Common problems identified in long-term captive animals, especially in Atelopus species, were epithelial squamous metaplasia suggestive of vitamin A deficiency and a polycystic nephropathy resembling lesions seen in laboratory animals with electrolyte imbalances. Metabolic bone disease was a significant contributor to morbidity in captive-bred juvenile frogs of Gastrotheca cornuta, Hemiphractus fasciatus, and Hylomantis lemur. Findings common to multiple species included poor overall nutritional condition that was sometimes attributable to maladaptation to captive husbandry and epidermal hyperplasia and hyperkeratosis possibly reflecting environmental skin irritation. Infectious diseases and endoparasitism were most common in recently captured animals and included chytridiomycosis and Rhabdias sp. lungworms. Applied research efforts to improve sustainability of survival assurance populations should focus on elucidating optimal husbandry practices for diverse species, improving methods for nutritional supplementation of cultured insects and examination of the role of water composition in disease development. PMID:25255888

  4. Immune defenses against Batrachochytrium dendrobatidis, a fungus linked to global amphibian declines, in the South African clawed frog, Xenopus laevis.

    Science.gov (United States)

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

    2010-09-01

    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 pathogen. After an experimental exposure, a mild infection developed over 20 to 30 days and declined by 45 days postexposure. Either purified antimicrobial peptides or mixtures of peptides in the skin mucus inhibited B. dendrobatidis growth in vitro. Skin peptide secretion was maximally induced by injection of norepinephrine, and this treatment resulted in sustained skin peptide depletion and increased susceptibility to infection. Sublethal X-irradiation of frogs decreased leukocyte numbers in the spleen and resulted in greater susceptibility to infection. Immunization against B. dendrobatidis induced elevated pathogen-specific IgM and IgY serum antibodies. Mucus secretions from X. laevis previously exposed to B. dendrobatidis contained significant amounts of IgM, IgY, and IgX antibodies that bind to B. dendrobatidis. These data strongly suggest that both innate and adaptive immune defenses are involved in the resistance of X. laevis to lethal B. dendrobatidis infections.

  5. Opposing resonses to ecological gradients structure amphibian and reptile communities across a temperate grassland-savanna-forest landscape

    Science.gov (United States)

    Grundel, Ralph; Beamer, David; Glowacki, Gary A.; Frohnapple, Krystal; Pavlovic, Noel B.

    2014-01-01

    Temperate savannas are threatened across the globe. If we prioritize savanna restoration, we should ask how savanna animal communities differ from communities in related open habitats and forests. We documented distribution of amphibian and reptile species across an open-savanna–forest gradient in the Midwest U.S. to determine how fire history and habitat structure affected herpetofaunal community composition. The transition from open habitats to forests was a transition from higher reptile abundance to higher amphibian abundance and the intermediate savanna landscape supported the most species overall. These differences warn against assuming that amphibian and reptile communities will have similar ecological responses to habitat structure. Richness and abundance also often responded in opposite directions to some habitat characteristics, such as cover of bare ground or litter. Herpetofaunal community species composition changed along a fire gradient from infrequent and recent fires to frequent but less recent fires. Nearby (200-m) wetland cover was relatively unimportant in predicting overall herpetofaunal community composition while fire history and fire-related canopy and ground cover were more important predictors of composition, diversity, and abundance. Increased developed cover was negatively related to richness and abundance. This indicates the importance of fire history and fire related landscape characteristics, and the negative effects of development, in shaping the upland herpetofaunal community along the native grassland–forest continuum.

  6. Control of respiration in fish, amphibians and reptiles.

    Science.gov (United States)

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

    2010-05-01

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

  7. A multilocus timescale for the origin of extant amphibians.

    Science.gov (United States)

    San Mauro, Diego

    2010-08-01

    One of the most hotly debated topics in vertebrate evolution is the origin of extant amphibians (Lissamphibia). The recent contribution of molecular data is shedding new light on this debate, but many important questions still remain unresolved. I have assembled a large and comprehensive multilocus dataset (the largest to date in terms of number and heterogeneity of sequence characters) combining mitogenomic and nuclear information from 23 genes for a sufficiently dense taxon sampling with the key major lineages of extant amphibians. This dataset has been used to infer a robust phylogenetic framework and molecular timescale for the origin of extant amphibians employing the most recent phylogenetic and dating methods, as well as several alternative calibration schemes. The monophyly of each extant amphibian order and the sister group relationship between frogs and salamanders (Batrachia hypothesis) are all strongly supported. Dating analyses (all methods and calibration schemes used) suggest that the origin of extant amphibians (divergence between caecilian and batrachians) occurred in the Late Carboniferous, around 315 Mya, and the divergence between frogs and salamanders occurred in the Early Permian, around 290 Mya. These age estimates are more consistent with the fossil record than previous older estimates, and more in line with the Temnospondyli or the Lepospondyli hypotheses of lissamphibian ancestry (although the polyphyly hypothesis cannot be completely ruled out).

  8. 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.

  9. 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.

  10. 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

  11. Discovering Hidden Diversity of Characins (Teleostei: Characiformes) in Ecuador’s Yasuní National Park

    Science.gov (United States)

    Escobar-Camacho, Daniel; Barriga, Ramiro; Ron, Santiago R.

    2015-01-01

    Background Management and conservation of biodiversity requires adequate species inventories. The Yasuní National Park is one of the most diverse regions on Earth and recent studies of terrestrial vertebrates, based on genetic evidence, have shown high levels of cryptic and undescribed diversity. Few genetic studies have been carried out in freshwater fishes from western Amazonia. Thus, in contrast with terrestrial vertebrates, their content of cryptic diversity remains unknown. In this study, we carried out genetic and morphological analyses on characin fishes at Yasuní National Park, in eastern Ecuador. Our goal was to identify cryptic diversity among one of the most speciose fish families in the Amazon region. This is the first time that genetic evidence has been used to assess the species content of the Napo Basin, one of the richest regions in vertebrate diversity. Results Phylogenetic analyses of partial mitochondrial 16S ribosomal RNA gene (∼600 pb) DNA sequences from 232 specimens of the family Characidae and its closest groups revealed eight candidate new species among 33 species sampled, representing a 24% increase in species number. Analyses of external morphology allowed us to confirm the species status of six of the candidate species. Conclusions Our results show high levels of cryptic diversity in Amazonian characins. If this group is representative of other Amazonian fish, our results would imply that the species richness of the Amazonian ichthyofauna is highly underestimated. Molecular methods are a necessary tool to obtain more realistic inventories of Neotropical freshwater fishes. PMID:26275041

  12. 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...

  13. Estimating greenhouse gas emissions from future Amazonian hydroelectric reservoirs

    International Nuclear Information System (INIS)

    Brazil plans to meet the majority of its growing electricity demand with new hydropower plants located in the Amazon basin. However, large hydropower plants located in tropical forested regions may lead to significant carbon dioxide and methane emission. Currently, no predictive models exist to estimate the greenhouse gas emissions before the reservoir is built. This paper presents two different approaches to investigate the future carbon balance of eighteen new reservoirs in the Amazon. The first approach is based on a degradation model of flooded carbon stock, while the second approach is based on flux data measured in Amazonian rivers and reservoirs. The models rely on a Monte Carlo simulation framework to represent the balance of the greenhouse gases into the atmosphere that results when land and river are converted into a reservoir. Further, we investigate the role of the residence time/stratification in the carbon emissions estimate. Our results imply that two factors contribute to reducing overall emissions from these reservoirs: high energy densities reservoirs, i.e., the ratio between the installed capacity and flooded area, and vegetation clearing. While the models’ uncertainties are high, we show that a robust treatment of uncertainty can effectively indicate whether a reservoir in the Amazon will result in larger greenhouse gas emissions when compared to other electricity sources. (letter)

  14. Poor prospects for avian biodiversity in Amazonian oil palm.

    Science.gov (United States)

    Lees, Alexander C; Moura, Nárgila G; de Almeida, Arlete Silva; Vieira, Ima C G

    2015-01-01

    Expansion of oil palm plantations across the humid tropics has precipitated massive loss of tropical forest habitats and their associated speciose biotas. Oil palm plantation monocultures have been identified as an emerging threat to Amazonian biodiversity, but there are no quantitative studies exploring the impact of these plantations on the biome's biota. Understanding these impacts is extremely important given the rapid projected expansion of oil palm cultivation in the basin. Here we investigate the biodiversity value of oil palm plantations in comparison with other dominant regional land-uses in Eastern Amazonia. We carried out bird surveys in oil palm plantations of varying ages, primary and secondary forests, and cattle pastures. We found that oil palm plantations retained impoverished avian communities with a similar species composition to pastures and agrarian land-uses and did not offer habitat for most forest-associated species, including restricted range species and species of conservation concern. On the other hand, the forests that the oil palm companies are legally obliged to protect hosted a relatively species-rich community including several globally-threatened bird species. We consider oil palm to be no less detrimental to regional biodiversity than other agricultural land-uses and that political pressure exerted by large landowners to allow oil palm to count as a substitute for native forest vegetation in private landholdings with forest restoration deficits would have dire consequences for regional biodiversity.

  15. Carbon Dioxide and Methane Evasion from Amazonian Rivers and Lakes

    Science.gov (United States)

    Melack, J. M.; Barbosa, P.; Schofield, V.; Amaral, J.; Forsberg, B.; Farjalla, V.

    2013-12-01

    Floodplains, with their mosaic of aquatic habitats, constitute the majority of the wetlands of South America. We report 1) estimates of CH4 and CO2 flux from Amazonian floodplain lakes and rivers during low, rising and high water periods, and 2) identify environmental factors regulating these fluxes. We sampled 10 floodplain lakes, 4 tributaries of Solimões River, 6 stations on the Solimões main stem and 1 station on the Madeira, Negro and Amazonas rivers. Diffusive fluxes were measured with static floating chambers. CH4 fluxes were highly variable, with the majority of the values lower than 5 mmol m-2 d-1. For the lakes, no significant differences among the periods were found. CH4 concentration in the water and water temperature were the two main environmental factors regulating the diffusive flux. Our results highlight the importance of considering both the spatial and temporal scales when estimating CH4 fluxes for a region. CO2 fluxes from water to atmosphere ranged between 327 and -21 mmol m-2 d-1, averaging 58 mmol m-2 d-1. We found higher evasion rates in lakes than in rivers. For both systems the lowest rates were found in low water. pH and dissolved oxygen, phosphorous and organic carbon were the main factors correlated to CO2 evasion from the water bodies.

  16. Poor prospects for avian biodiversity in Amazonian oil palm.

    Directory of Open Access Journals (Sweden)

    Alexander C Lees

    Full Text Available Expansion of oil palm plantations across the humid tropics has precipitated massive loss of tropical forest habitats and their associated speciose biotas. Oil palm plantation monocultures have been identified as an emerging threat to Amazonian biodiversity, but there are no quantitative studies exploring the impact of these plantations on the biome's biota. Understanding these impacts is extremely important given the rapid projected expansion of oil palm cultivation in the basin. Here we investigate the biodiversity value of oil palm plantations in comparison with other dominant regional land-uses in Eastern Amazonia. We carried out bird surveys in oil palm plantations of varying ages, primary and secondary forests, and cattle pastures. We found that oil palm plantations retained impoverished avian communities with a similar species composition to pastures and agrarian land-uses and did not offer habitat for most forest-associated species, including restricted range species and species of conservation concern. On the other hand, the forests that the oil palm companies are legally obliged to protect hosted a relatively species-rich community including several globally-threatened bird species. We consider oil palm to be no less detrimental to regional biodiversity than other agricultural land-uses and that political pressure exerted by large landowners to allow oil palm to count as a substitute for native forest vegetation in private landholdings with forest restoration deficits would have dire consequences for regional biodiversity.

  17. Sexual selection drives speciation in an Amazonian frog

    Science.gov (United States)

    Boul, K.E.; Funk, W.C.; Darst, C.R.; Cannatella, D.C.; Ryan, M.J.

    2007-01-01

    One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation. Despite the appeal of this hypothesis, evidence for it remains inconclusive. Here, we present several lines of evidence that sexual selection is driving behavioural isolation and speciation among populations of an Amazonian frog (Physalaemus petersi). First, sexual selection has promoted divergence in male mating calls and female preferences for calls between neighbouring populations, resulting in strong behavioural isolation. Second, phylogenetic analysis indicates that populations have become fixed for alternative call types several times throughout the species' range, and coalescent analysis rejects genetic drift as a cause for this pattern, suggesting that this divergence is due to selection. Finally, gene flow estimated with microsatellite loci is an average of 30 times lower between populations with different call types than between populations separated by a similar geographical distance with the same call type, demonstrating genetic divergence and incipient speciation. Taken together, these data provide strong evidence that sexual selection is driving behavioural isolation and speciation, supporting sexual selection as a cause for speciation in the wild. ?? 2006 The Royal Society.

  18. Branchfall dominates annual carbon flux across lowland Amazonian forests

    Science.gov (United States)

    Marvin, David C.; Asner, Gregory P.

    2016-09-01

    Tropical forests play an important role in the global carbon cycle, but knowledge of interannual variation in the total tropical carbon flux and constituent carbon pools is highly uncertain. One such pool, branchfall, is an ecologically important dynamic with links to nutrient cycling, forest productivity, and drought. Identifying and quantifying branchfall over large areas would reveal the role of branchfall in carbon and nutrient cycling. Using data from repeat airborne light detection and ranging campaigns across a wide array of lowland Amazonian forest landscapes totaling nearly 100 000 ha, we find that upper canopy gaps—driven by branchfall—are pervasive features of every landscape studied, and are seven times more frequent than full tree mortality. Moreover, branchfall comprises a major carbon source on a landscape basis, exceeding that of tree mortality by 21%. On a per hectare basis, branchfall and tree mortality result in 0.65 and 0.72 Mg C ha-1 yr-1 gross source of carbon to the atmosphere, respectively. Reducing uncertainties in annual gross rates of tropical forest carbon flux, for example by incorporating large-scale branchfall dynamics, is crucial for effective policies that foster conservation and restoration of tropical forests. Additionally, large-scale branchfall mapping offers ecologists a new dimension of disturbance monitoring and potential new insights into ecosystem structure and function.

  19. The impact of Amazonian deforestation on Amazon basin rainfall

    Science.gov (United States)

    Spracklen, D. V.; Garcia-Carreras, L.

    2015-11-01

    We completed a meta-analysis of regional and global climate model simulations (n = 96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12 ± 11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simulate a nonlinear response. Using the linear relationship, we estimate that deforestation in 2010 has reduced annual mean rainfall across the Amazon basin by 1.8 ± 0.3%, less than the interannual variability in observed rainfall. This may explain why a reduction in Amazon rainfall has not consistently been observed. We estimate that business-as-usual deforestation (based on deforestation rates prior to 2004) would lead to an 8.1 ± 1.4% reduction in annual mean Amazon basin rainfall by 2050, greater than natural variability.

  20. Use of amazonian anthropogenic soils: Comparison between Caboclos communities and Tikunas indigenous group

    International Nuclear Information System (INIS)

    In general terms, Amazonian soils are infertile and have several constraints for agricultural production. However, use by ancient human societies since pre-columbian times has driven landscape transformation of massive areas and development of anthropogenic soils called Terra Preta do Indio (TP) or Amazonian Dark Earths (ADE). ADE characterization, in terms of fertility and composition, has allowed the development of intensive agricultural activities over time. The current use of ADE for the Brazilian amazon peasants (Caboclos) is different from the indigenous communities in Colombia. The indigenous people in Colombia (Tikunas) no use this type of soils on behalf of cultural restrictions that avoid the use of ancient places. We are comparing the institutional conditions, migrations, social characterization and cultural factors that determine the use/no-use of these soils by the Amazonian societies.

  1. Ocurrence of Cryptosporidium spp. in Amazonian manatees (Trichechus inunguis, Natterer, 1883

    Directory of Open Access Journals (Sweden)

    Maria Aparecida da Glória Faustino

    2007-09-01

    Full Text Available The apicomplexa protozoa Cryptosporidium infects several mammals, including terrestrial and aquatic species. In the epidemiology of this infection, the ingestion of water and/or food contamined with oocysts comprises the main mechanism of transmission to susceptible animals. Among the Sirenians, the occurrence of this coccidium has been reported in dugongs (Dugong dugon and Antillean manatee (Trichechus manatus manatus. The present study was conducted with the aim of verifying the occurrence of Cryptosporidium spp. in Amazonian manatee. For this purpose, fecal samples were collected from ten free-ranging Amazonian manatees, two specimens in captivity, and 103 supernatants fecal samples. The samples were processed by the sedimentation method in formol-ether and Kinyoun stain technique for the presence of Cryptosporidium spp.. The positive samples were then submitted to Direct Immunoflorescence Test. The results showed 4.34% (05/115 of positive samples. This is the first report of Cryptosporidium spp. in the Amazonian manatee.

  2. Complete mitochondrial genome of Nanorana pleskei (Amphibia: Anura: Dicroglossidae and evolutionary characteristics of the amphibian mitochondrial genomes

    Directory of Open Access Journals (Sweden)

    Guiying CHEN, Bin WANG, Jiongyu LIU, Feng XIE, Jianping JIANG

    2011-12-01

    Full Text Available The complete mitochondrial genome of Nanorana pleskei from the Qinghai-Tibet Plateau was sequenced. It includes 17,660 base pairs, containing 13 protein-coding genes, two rRNAs and 23 tRNAs. A tandem duplication of tRNAMet gene was found in this mitochondrial genome, and the similarity between the two tRNAMet genes is 85.8%, being the highest in amphibian mitochondrial genomes sequenced thus far. Based on gene organization, 24 types were found from 145 amphibian mitochondrial genomes. Type 1 was present in 108 species, type 11 in 11 species, types 5, 16, 17, and 20 each in two species, and the others each present in one species. Fifteen types were found in Anura, being the most diversity in three orders of the Lissamphibia. Our phylogenetic results using 11 protein-coding gene sequences of 145 amphibian mitochondrial genomes strongly support the monophyly of the Lissamphibia, as well as its three orders, the Gymnophiona, Caudata, and Anura, among which the relationships were ((Gymnophiona (Caudata, Anura. Based on the phylogenetic trees, type 1 was recognized as the ancestral type for amphibians, and type 11 was the synapomorphic type for the Neobatrachia. Gene rearrangements among lineages provide meaningful phylogenetic information. The rearrangement of the LTPF tRNA gene cluster and the translocation of the ND5 gene only found in the Neobatrachia support the monophyly of this group; similarly, the tandem duplication of the tRNAMet genes only found in the Dicroglossidae support the monophyly of this family [Current Zoology 57 (6: 785–805, 2011].

  3. Qualitative risk analysis of introducing Batrachochytrium dendrobatidis to the UK through the importation of live amphibians.

    Science.gov (United States)

    Peel, Alison J; Hartley, Matt; Cunningham, Andrew A

    2012-03-20

    The international amphibian trade is implicated in the emergence and spread of the amphibian fungal disease chytridiomycosis, which has resulted in amphibian declines and extinctions globally. The establishment of the causal pathogen, Batrachochytrium dendrobatidis (Bd), in the UK could negatively affect the survival of native amphibian populations. In recognition of the ongoing threat that it poses to amphibians, Bd was recently included in the World Organisation for Animal Health Aquatic Animal Health Code, and therefore is in the list of international notifiable diseases. Using standardised risk analysis guidelines, we investigated the likelihood that Bd would be introduced to and become established in wild amphibians in the UK through the importation of live amphibians. We obtained data on the volume and origin of the amphibian trade entering the UK and detected Bd infection in amphibians being imported for the pet and private collection trade and also in amphibians already held in captive pet, laboratory and zoological collections. We found that current systems for recording amphibian trade into the UK underestimate the volume of non-European Union trade by almost 10-fold. We identified high likelihoods of entry, establishment and spread of Bd in the UK and the resulting major overall impact. Despite uncertainties, we determined that the overall risk estimation for the introduction of Bd to the UK through the importation of live amphibians is high and that risk management measures are required, whilst ensuring that negative effects on legal trade are minimised.

  4. 50 CFR 16.14 - Importation of live amphibians or their eggs.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Importation of live amphibians or their... Importation of live amphibians or their eggs. Upon the filing of a written declaration with the District Director of Customs at the port of entry as required under § 14.61, all species of live amphibians or...

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

    Science.gov (United States)

    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 (the Caudata Pleurodeles waltl, Salamandra salamandra, Lissotriton boscai, Triturus marmoratus and the anurans Pelobates cultripes and Hyla arborea/meridionalis) occupying 88 ponds. The study was conducted in a Mediterranean landscape dominated by eucalypt plantations alternated with traditional use (agricultural, montados and native forest) at three different scales: local (pond), intermediate (400 metres radius buffer) and broad (1000 metres radius buffer). Using the Akaike Information Criterion for small samples (AICc), we selected the top-ranked models for estimating the probability of occurrence of each species at each spatial scale separately and across all three spatial scales, using a combination of covariates from the different magnitudes. Models with a combination of covariates at the different spatial scales had a stronger support than those at individual scales. The presence of predatory fish in a pond had a strong effect on Caudata presence. Permanent ponds were selected by Hyla arborea/meridionalis over temporary ponds. Species occurrence was not increased by a higher density of streams, but the density of ponds impacted negatively on Lissotriton boscai. The proximity of ponds occupied by their conspecifics had a positive effect on the occurrence of Lissotriton boscai and Pleurodeles waltl. Eucalypt plantations had a negative effect on the occurrence of the newt Lissotriton boscai and anurans Hyla arborea/meridionalis, but had a positive effect on the presence of

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

    Directory of Open Access Journals (Sweden)

    Joana Cruz

    Full Text Available 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 (the Caudata Pleurodeles waltl, Salamandra salamandra, Lissotriton boscai, Triturus marmoratus and the anurans Pelobates cultripes and Hyla arborea/meridionalis occupying 88 ponds. The study was conducted in a Mediterranean landscape dominated by eucalypt plantations alternated with traditional use (agricultural, montados and native forest at three different scales: local (pond, intermediate (400 metres radius buffer and broad (1000 metres radius buffer. Using the Akaike Information Criterion for small samples (AICc, we selected the top-ranked models for estimating the probability of occurrence of each species at each spatial scale separately and across all three spatial scales, using a combination of covariates from the different magnitudes. Models with a combination of covariates at the different spatial scales had a stronger support than those at individual scales. The presence of predatory fish in a pond had a strong effect on Caudata presence. Permanent ponds were selected by Hyla arborea/meridionalis over temporary ponds. Species occurrence was not increased by a higher density of streams, but the density of ponds impacted negatively on Lissotriton boscai. The proximity of ponds occupied by their conspecifics had a positive effect on the occurrence of Lissotriton boscai and Pleurodeles waltl. Eucalypt plantations had a negative effect on the occurrence of the newt Lissotriton boscai and anurans Hyla arborea/meridionalis, but had a positive effect on

  7. progress and prospects for studies on chinese amphibians

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    this work summarizes the history and progress of the studies on chinese amphibians since they first appeared in the chinese literature.a wide range of research has been carried out,including the history of the definition of amphibians,faunal surveys,systematic research,ecological research,biochemical research (isozyme and other proteins or peptides,chromosomes,dna),anatomical research,embryological research,phylogenetic and zoogeographical research,and many others such as ultrastructure of organs,crossbreeding test,regeneration of organs,abnormality survey,acoustics,fossils,sperm ultrastructure and parasites.in addition,the prospects for studies on chinese amphibians in future are proposed in this paper.

  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. The invasive chytrid fungus of amphibians paralyzes lymphocyte responses.

    Science.gov (United States)

    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

    2013-10-18

    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 supernatants impaired lymphocyte proliferation and induced apoptosis; however, fungal recognition and phagocytosis by macrophages and neutrophils was not impaired. Fungal inhibitory factors were resistant to heat, acid, and protease. Their production was absent in zoospores and reduced by nikkomycin Z, suggesting that they may be components of the cell wall. Evasion of host immunity may explain why this pathogen has devastated amphibian populations worldwide.

  10. Evidence for ecological divergence across a mosaic of soil types in an Amazonian tropical tree: Protium subserratum (Burseraceae).

    Science.gov (United States)

    Misiewicz, Tracy M; Fine, Paul V A

    2014-05-01

    Soil heterogeneity is an important driver of divergent natural selection in plants. Neotropical forests have the highest tree diversity on earth, and frequently, soil specialist congeners are distributed parapatrically. While the role of edaphic heterogeneity in the origin and maintenance of tropical tree diversity is unknown, it has been posited that natural selection across the patchwork of soils in the Amazon rainforest is important in driving and maintaining tree diversity. We examined genetic and morphological differentiation among populations of the tropical tree Protium subserratum growing parapatrically on the mosaic of white-sand, brown-sand and clay soils found throughout western Amazonia. Nuclear microsatellites and leaf morphology were used to (i) quantify the extent of phenotypic and genetic divergence across habitat types, (ii) assess the importance of natural selection vs. drift in population divergence, (iii) determine the extent of hybridization and introgression across habitat types, (iv) estimate migration rates among populations. We found significant morphological variation correlated with soil type. Higher levels of genetic differentiation and lower migration rates were observed between adjacent populations found on different soil types than between geographically distant populations on the same soil type. PST -FST comparisons indicate a role for natural selection in population divergence among soil types. A small number of hybrids were detected suggesting that gene flow among soil specialist populations may occur at low frequencies. Our results suggest that edaphic specialization has occurred multiple times in P. subserratum and that divergent natural selection across edaphic boundaries may be a general mechanism promoting and maintaining Amazonian tree diversity.

  11. Game depletion hypothesis of amazonian adaptation: data from a native community.

    Science.gov (United States)

    Vickers, W T

    1988-03-25

    The low population densities and impermanent settlements of Amazonian Indians are often interpreted as adaptations to a fauna that offers limited protein resources and is rapidly depleted by hunting. Data spanning the 10-year life cycle of one northwestern Amazonian settlement show that variations in hunt yields result from temporal variations in peccary (Tayassu pecari and T. tajacu) kills that appear extrinsic to native population size. After 10 years, hunting success remained high and the kill rates for most prey did not suggest depletion. An array of environmental factors accounts for the incipient settlement relocation observed.

  12. Paleogenomic data suggest mammal-like genome size in the ancestral amniote and derived large genome size in amphibians.

    Science.gov (United States)

    Organ, C L; Canoville, A; Reisz, R R; Laurin, M

    2011-02-01

    An unsolved question in evolutionary genomics is whether amniote genomes have been expanding or contracting since the common ancestor of this diverse group. Here, we report on the polarity of amniote genome size evolution using genome size estimates for 14 extinct tetrapod genera from the Paleozoic and early Mesozoic Eras using osteocyte lacunae size as a correlate. We find substantial support for a phylogenetically controlled regression model relating genome size to osteocyte lacunae size (P of slopes amphibians, contractions along the diapsid lineage, and no directional change within the synapsid lineage leading to mammals.

  13. The Amphibian Research and Monitoring Initiative in the Pacific Northwest

    Science.gov (United States)

    Adams, Michael J.

    2003-01-01

    Amphibians have been disappearing from many locations around the world with reports of declines increasing in recent decades. Some of the most dramatic declines have occurred in areas that were thought to be protected from human disturbance. For example, the once-common boreal toad has virtually disappeared from Rocky Mountain National Park in Colorado. Although there has been debate on whether these declines represent a short-term fluctuation in populations or major sustained losses, there is now general scientific consensus that something really is amiss with amphibian populations.

  14. Amphibian decline: An integrated analysis of multiple stressor effects

    Science.gov (United States)

    Linder, G.; Krest, S.K.; Sparling, D. W.; Linder, G.; Krest, S.K.; Sparling, D.W.

    2003-01-01

    Capturing the attention and imagination of the public and the scientific community alike, the mysterious decline in amphibian populations drew scientists and resource managers from ecotoxicology and chemistry, ecology and field biology, conservation biology, and natural resource policy to a SETAC–Johnson Foundation workshop. Facilitating environmental stewardship, increasing capacity of the sciences to explain complex stressors, and educating the public on relationships among communities of all types motivated these experts to address amphibian decline and the role of various stressors in these losses.

  15. 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

    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...... amphibian orders and across biogeographical regions. To our knowledge, this is the first study providing a comprehensive analysis of the phylogenetic signal in species climatic niches for an entire clade across the world. Even though our results do not provide a strong test of the niche conservatism...

  16. Equilibrium of global amphibian species distributions with climate

    DEFF Research Database (Denmark)

    Munguí­a, Mariana; Rahbek, Carsten; Rangel, Thiago F.;

    2012-01-01

    for 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...... 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 smaller proportion...

  17. Amazonian Buriti oil: chemical characterization and antioxidant potential

    Directory of Open Access Journals (Sweden)

    Speranza, P.

    2016-06-01

    Full Text Available Buriti oil is an example of an Amazonian palm oil of economic importance. The local population uses this oil for the prevention and treatment of different diseases; however, there are few studies in the literature that evaluate its properties. In this study, detailed chemical and antioxidant properties of Buriti oil were determined. The predominant fatty acid was oleic acid (65.6% and the main triacylglycerol classes were tri-unsaturated (50.0% and di-unsaturated-mono-saturated (39.3% triacylglycerols. The positional distribution of the classes of fatty acids on the triacylglycerol backbone indicated a saturated and unsaturated fatty acid relationship similar in the three-triacylglycerol positions. All tocopherol isomers were present, with a total content of 2364.1 mg·kg−1. α-tocopherol constitutes 48% of the total tocopherol content, followed by γ- tocopherol (45%. Total phenolic (107.0 mg gallic acid equivalent·g−1 oil and β-carotene (781.6 mg·kg−1 were particularly high in this oil. The highest antioxidant activity against the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH was obtained at an oil concentration of 50 mg·mL−1 (73.15%. The antioxidant activity evaluated by the Oxygen Radical Absorbance Capacity (ORAC was 95.3 μmol Trolox equivalent·g−1 oil. These results serve to present Buriti oil as an Amazonian resource for cosmetic, food and pharmaceuticals purposes.El aceite de Buriti es un ejemplo de aceite de palma amazónica de gran importancia económica. La población local utiliza este aceite para la prevención y el tratamiento de diferentes enfermedades; sin embargo, hay pocos estudios científicos que evalúen sus propiedades. En este estudio, se determinaron las propiedades antioxidantes del aceite de Buriti. El ácido graso predominante fue el oleico (65,6 % y las principales clases de triglicéridos fueron tri-insaturadas (50,0 % y Di-insaturados-mono-saturada (39,3 %. La distribución posicional de las

  18. Thresholds of species loss in Amazonian deforestation frontier landscapes.

    Science.gov (United States)

    Ochoa-Quintero, Jose Manuel; Gardner, Toby A; Rosa, Isabel; Ferraz, Silvio Frosini de Barros; Sutherland, William J

    2015-04-01

    In the Brazilian Amazon, private land accounts for the majority of remaining native vegetation. Understanding how land-use change affects the composition and distribution of biodiversity in farmlands is critical for improving conservation strategies in the face of rapid agricultural expansion. Working across an area exceeding 3 million ha in the southwestern state of Rondônia, we assessed how the extent and configuration of remnant forest in replicate 10,000-ha landscapes has affected the occurrence of a suite of Amazonian mammals and birds. In each of 31 landscapes, we used field sampling and semistructured interviews with landowners to determine the presence of 28 large and medium sized mammals and birds, as well as a further 7 understory birds. We then combined results of field surveys and interviews with a probabilistic model of deforestation. We found strong evidence for a threshold response of sampled biodiversity to landscape level forest cover; landscapes with deforested landscapes many species are susceptible to extirpation following relatively small additional reductions in forest area. In the model of deforestation by 2030 the number of 10,000-ha landscapes under a conservative threshold of 43% forest cover almost doubled, such that only 22% of landscapes would likely to be able to sustain at least 75% of the 35 focal species we sampled. Brazilian law requires rural property owners in the Amazon to retain 80% forest cover, although this is rarely achieved. Prioritizing efforts to ensure that entire landscapes, rather than individual farms, retain at least 50% forest cover may help safeguard native biodiversity in private forest reserves in the Amazon. PMID:25580947

  19. Reptile and amphibian responses to large-scale wildfires in southern California

    Science.gov (United States)

    Rochester, C.J.; Brehme, C.S.; Clark, D.R.; Stokes, D.C.; Hathaway, S.A.; Fisher, R.N.

    2010-01-01

    In 2003, southern California experienced several large fires that burned thousands of hectares of wildlife habitats and conserved lands. To investigate the effects of these fires on the reptile and amphibian communities, we compared the results from prefire herpetofauna and vegetation sampling to two years of postfire sampling across 38 burned and 17 unburned plots. The sampling plots were spread over four vegetation types and four open space areas within San Diego County. Our capture results indicated that burned chaparral and coastal sage scrub plots lost herpetofaunal species diversity after the fires and displayed a significant shift in overall community structure. Shrub and tree cover at the burned plots, averaged across the second and third postfire years, had decreased by 53 in chaparral and 75 in coastal sage scrub. Additionally, postfire herpetofauna community structure at burned plots was more similar to that found in unburned grasslands. In grassland and woodland/riparian vegetation plots, where shrub and tree cover was not significantly affected by fires, we found no differences in the herpetofaunal species diversity or community composition. At the individual species level, Sceloporus occidentalis was the most abundant reptile in these areas both before and after the fires. We saw increases in the net capture rates for several lizard species, including Aspidoscelis tigris, Phrynosoma coronatum, and Uta stansburiana in burned chaparral plots and Aspidoscelis hyperythra and U. stansburiana in burned coastal sage scrub plots. The toad, Bufo boreas, was detected at significantly fewer burned plots in chaparral after the fires. Additionally, we documented decreases in the number of plots occupied by lizards (Elgaria multicarinata), salamanders (Batrachoseps major), and snakes (Coluber constrictor, Lampropeltis getula, Pituophis catenifer, and Masticophis lateralis) in coastal sage scrub and chaparral after the fires. We discuss the individual species

  20. 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.

  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. Glyphosate applications on arable fields considerably coincide with migrating amphibians.

    Science.gov (United States)

    Berger, Gert; Graef, Frieder; Pfeffer, Holger

    2013-01-01

    Glyphosate usage is increasing worldwide and the application schemes of this herbicide are currently changing. Amphibians migrating through arable fields may be harmed by Glyphosate applied to field crops. We investigated the population-based temporal coincidence of four amphibian species with Glyphosate from 2006 to 2008. Depending on a) age- and species-specific main migration periods, b) crop species, c) Glyphosate application mode for crops, and d) the presumed DT50 value (12 days or 47 days) of Glyphosate, we calculated up to 100% coincidence with Glyphosate. The amphibians regularly co-occur with pre-sowing/pre-emerging Glyphosate applications to maize in spring and with stubble management prior to crop sowing in late summer and autumn. Siccation treatment in summer coincides only with early pond-leaving juveniles. We suggest in-depth investigations of both acute and long-term effects of Glyphosate applications on amphibian populations not only focussed on exposure during aquatic periods but also terrestrial life stages.

  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. Batrachochytrium salamandrivorans sp. nov. causes lethal chytridiomycosis in amphibians.

    Science.gov (United States)

    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

    2013-09-17

    The current biodiversity crisis encompasses a sixth mass extinction event affecting the entire class of amphibians. The infectious disease chytridiomycosis is considered one of the major drivers of global amphibian population decline and extinction and is thought to be caused by a single species of aquatic fungus, Batrachochytrium dendrobatidis. However, several amphibian population declines remain unexplained, among them a steep decrease in fire salamander populations (Salamandra salamandra) that has brought this species to the edge of local extinction. Here we isolated and characterized a unique chytrid fungus, Batrachochytrium salamandrivorans sp. nov., from this salamander population. This chytrid causes erosive skin disease and rapid mortality in experimentally infected fire salamanders and was present in skin lesions of salamanders found dead during the decline event. Together with the closely related B. dendrobatidis, this taxon forms a well-supported chytridiomycete clade, adapted to vertebrate hosts and highly pathogenic to amphibians. However, the lower thermal growth preference of B. salamandrivorans, compared with B. dendrobatidis, and resistance of midwife toads (Alytes obstetricans) to experimental infection with B. salamandrivorans suggest differential niche occupation of the two chytrid fungi.

  5. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe.

    Science.gov (United States)

    Spitzen-van der Sluijs, Annemarieke; Martel, An; Asselberghs, Johan; Bales, Emma K; Beukema, Wouter; Bletz, Molly C; Dalbeck, Lutz; Goverse, Edo; Kerres, Alexander; Kinet, Thierry; Kirst, Kai; Laudelout, Arnaud; Marin da Fonte, Luis F; Nöllert, Andreas; Ohlhoff, Dagmar; Sabino-Pinto, Joana; Schmidt, Benedikt R; Speybroeck, Jeroen; Spikmans, Frank; Steinfartz, Sebastian; Veith, Michael; Vences, Miguel; Wagner, Norman; Pasmans, Frank; Lötters, Stefan

    2016-07-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.

  6. 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].

  7. 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.

  8. On the worrying fate of Data Deficient amphibians.

    Science.gov (United States)

    Nori, Javier; Loyola, Rafael

    2015-01-01

    The 'Data Deficient' (DD) category of the IUCN Red List assembles species that cannot be placed in another category due to insufficient information. This process generates uncertainty about whether these species are safe or actually in danger. Here, we give a global overview on the current situation of DD amphibian species (almost a quarter of living amphibians) considering land-use change through habitat modification, the degree of protection of each species and the socio-political context of each country harboring DD species. We found that DD amphibians have, on average, 81% of their ranges totally outside protected areas. Worryingly, more than half of DD species have less than 1% of their distribution represented in protected areas. Furthermore, the percentage of overlap between species' range and human-modified landscapes is high, at approximately 58%. Many countries harboring a large number of DD species show a worrying socio-political trend illustrated by substantial, recent incremental increases in the Human Development Index and lower incremental increases in the establishment of protected areas. Most of these are African countries, which are located mainly in the central and southern regions of the continent. Other countries with similar socio-political trends are in southeastern Asia, Central America, and in the northern region of South America. This situation is concerning, but it also creates a huge opportunity for considering DD amphibians in future conservation assessments, planning, and policy at different levels of government administration.

  9. 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...

  10. AMPHIBIAN DECLINE, ULTRAVIOLET RADIATION AND LOCAL POPULATION ADAPTATION

    Science.gov (United States)

    Amphibian population declines have been noted on both local and global scales. Causes for these declines are unknown although many hypotheses have been offered. In areas adjacent to human development, loss of habitat is a fairly well accepted cause. However in isolated, seemingl...

  11. 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.

  12. 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.

  13. ESTIMATION OF UV-B EXPOSURE IN AMPHIBIAN AQUATIC ENVIRONMENTS

    Science.gov (United States)

    Estimation of ultraviolet radiation B (UV-B; 280 to 320 nm wavelenghts) dose is essential for determining whether UV-B contributes to amphibian population declines and malformations. UV-B dose in wetlands is effected by location, time of day and year, atmospheric levels of ozone,...

  14. 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.

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

    Science.gov (United States)

    Puglis, Holly J; Boone, Michelle D

    2012-01-01

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

  16. 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

  17. Preliminary amphibian surveys : Baca National Wildlife Refuge : July & August, 2015

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes an initial amphibian survey effort on the Baca National Wildlife Refuge, conducted on 7/17/15, 7/24/15, and 8/28/15. The main emphasis of...

  18. Recent (Late Amazonian) enhanced backweathering rates on Mars : Paracratering evidence from gully alcoves

    NARCIS (Netherlands)

    De Haas, Tjalling; Conway, Susan J.; Krautblatter, Michael

    2015-01-01

    Mars is believed to have been exposed to low planet-wide weathering and denudation since the Noachian. However, the widespread occurrence of alcoves at the rim of pristine impact craters suggests locally enhanced recent backweathering rates. Here we derive Late Amazonian backweathering rates from th

  19. The Perceptions of Knowledge and Learning of Amazonian Indigenous Teacher Education Students

    Science.gov (United States)

    Veintie, Tuija; Holm, Gunilla

    2010-01-01

    This study focuses on the perceptions of knowledge and learning by indigenous students in an intercultural bilingual teacher education programme in Amazonian Ecuador. The study framed within postcolonial and critical theory attempts to create a space for the indigenous students to speak about their own views through the use of photography and…

  20. Notes on Amazonian Bittacidae (Mecoptera with the descriptions of two new species

    Directory of Open Access Journals (Sweden)

    Norman D. Penny

    1982-09-01

    Full Text Available New species of Issikiella and Nannobittacus are described and notes are presented on other Amazonian species of Mecoptera.Nova espécie de Issikiella e Nannobittacus são descritas e notas são apresentadas para outras espécies de Mecopteros da Amazônia.

  1. Evolutionary patterns of range size, abundance and species richness in Amazonian angiosperm trees

    Science.gov (United States)

    Chave, Jérôme

    2016-01-01

    Amazonian tree species vary enormously in their total abundance and range size, while Amazonian tree genera vary greatly in species richness. The drivers of this variation are not well understood. Here, we construct a phylogenetic hypothesis that represents half of Amazonian tree genera in order to contribute to explaining the variation. We find several clear, broad-scale patterns. Firstly, there is significant phylogenetic signal for all three characteristics; closely related genera tend to have similar numbers of species and similar mean range size and abundance. Additionally, the species richness of genera shows a significant, negative relationship with the mean range size and abundance of their constituent species. Our results suggest that phylogenetically correlated intrinsic factors, namely traits of the genera themselves, shape among lineage variation in range size, abundance and species richness. We postulate that tree stature may be one particularly relevant trait. However, other traits may also be relevant, and our study reinforces the need for ambitious compilations of trait data for Amazonian trees. In the meantime, our study shows how large-scale phylogenies can help to elucidate, and contribute to explaining, macroecological and macroevolutionary patterns in hyperdiverse, yet poorly understood regions like the Amazon Basin. PMID:27651991

  2. Amazonian Dark Earth and plant species from the Amazon region contribute to shape rhizosphere bacterial communities

    NARCIS (Netherlands)

    Barbosa Lima, A.; Souza Cannavan, F.S.; Navarrete, A.A.; Kuramae, E.E.; Teixeira, W.G.; Tsai, S.M.

    2015-01-01

    Amazonian Dark Earths (ADE) or Terra Preta de Índio formed in the past by pre-Columbian populations are highly sustained fertile soils supported by microbial communities that differ from those extant in adjacent soils. These soils are found in the Amazon region and are considered as a model soil whe

  3. Governance of global climate change in the Brazilian Amazon: the case of Amazonian municipalities of Brazil

    Directory of Open Access Journals (Sweden)

    Cristina Inoue

    2012-01-01

    Full Text Available With regards to the debate about governance of climate change, it should be assumed that the Amazon region plays an important role, as this large area is highly vulnerable to its effects. In this sense, this article aims to discuss how some Amazonian municipalities of Brazil have been taking part in the complexes and multilayered processes of climate governance.

  4. Legacies of Amazonian dark earths on forest composition, structure and dynamics

    NARCIS (Netherlands)

    Quintero Vallejo, E.M.

    2015-01-01

    Summary

    Amazonian forest is seen as the archetype of pristine forests, untouched by humans, but this romantic view is far from reality. In recent years, there is increasing evidence of long and extensive landscape modification by humans. Processes of permanent inhabitation,

  5. Morphology, morphometry and ultrastructure of the Amazonian manatee (Sirenia: Trichechidae spermatozoa

    Directory of Open Access Journals (Sweden)

    Rodrigo S. Amaral

    2010-01-01

    Full Text Available This study describes the morphological, morphometric and ultrastructural characteristics of the Amazonian manatee Trichechus inunguis (Natterer, 1883 spermatozoon. The spermatozoa were obtained from a urine sample of an adult T. inunguis kept in captivity. The spermatozoa were analyzed by light and transmission electron microscopy. The head of Amazonian manatee spermatozoa had a flat oval shape and a well distinguishable midpiece. The mean dimensions of the spermatozoa were: head length, 7.49 ± 0.24 µm; head width, 3.53 ± 0.19 µm; head thickness, 1.61 ± 0.13 µm; midpiece length, 11.36 ± 0.34 µm; flagellum length, 40.91 ± 1.94 µm; total tail length, 52.16 ± 1.06 µm; total spermatozoon length, 60.08 ± 1.40 µm. The Amazonian manatee spermatozoa were similar in shape to other sirenian spermatozoa; however, presenting a different size. This study describes, for the first time, the morphometric and ultrastructural characteristics of the Amazonian manatee spermatozoa, and also demonstrates the possible use of spermatozoa retrieved from urine samples for biological studies.

  6. The Amazonian Craton and its influence on past fluvial systems (Mesozoic-Cenozoic, Amazonia)

    NARCIS (Netherlands)

    C. Hoorn; M. Roddaz; R. Dino; E. Soares; C. Uba; D. Ochoa-Lozano; R. Mapes

    2010-01-01

    The Amazonian Craton is an old geological feature of Archaean/Proterozoic age that has determined the character of fluvial systems in Amazonia throughout most of its past. This situation radically changed during the Cenozoic, when uplift of the Andes reshaped the relief and drainage patterns of nort

  7. The development of the Amazonian mega-wetland (Miocene; Brazil, Colombia, Peru, Bolivia)

    NARCIS (Netherlands)

    C. Hoorn; F.P. Wesselingh; J. Hovikoski; J. Guerrero

    2010-01-01

    The scenery of Western Amazonia once consisted of fluvial systems that originated on the Amazonian Craton and were directed towards the sub-Andean zone and the Caribbean. In the course of the Early Miocene these fluvial systems were largely replaced by lakes, swamps, tidal channels and marginal mari

  8. [Myths concerning malarial transmission among Amazonian Indians and their relation with 2 types of transmission encountered in the Amazonian forest].

    Science.gov (United States)

    Molez, J F

    1999-01-01

    Among the Indians Desana's (Tukano amerindians) in the Upper Rio Negro, the interseasonal variation of the malarial fevers were associated with two myths (localised in two distinguishable places). One myth associates the malarial with the rivers which contain "malaria pots". Conception based on an observation of localised water collection in the banks and the rocky rapids ("banks and rocky's fever"). The transmission and the anophelian density present variation between the seasons in relation to the river's level. Another myth associates malarial fevers in the forest, with the song of a frog ("fever's frog") and the flowering and fructification of a tree (Poaqueira sericea Thul.). There is in South America a particular type of forest malaria, known as "Bromelia malaria" and denounced in human and/or simian transmission. This forest malaria is transmitted by the a sub-genus anopheles (Kerteszia) which larval breeding are areal in the canopy. The breeding places are found in the forest in the epiphyte bromeliads. To understand this type of transmission, we must take reference to the previous endomological data at the Upper Oyapock Wayâpi (Tupi amerindians). This Bromelia malaria could fluctuated according larval density variation, related to washing of epiphytes (end of the rainy season) or to their flowering (end of the dry season). The "fever's frog" myth collected at the Desana's in the Upper Rio Negro can be related to the existence of Bromelia malaria in this amazonian habitat. These myths showed the perfect adaptation of the amerindians to their environment and their complete knowledge of the neotropical forest.

  9. 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.

  10. 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

  11. Bioaccumulation and maternal transfer of mercury and selenium in amphibians.

    Science.gov (United States)

    Bergeron, Christine M; Bodinof, Catherine M; Unrine, Jason M; Hopkins, William A

    2010-04-01

    Amphibian population declines have been documented worldwide and environmental contaminants are believed to contribute to some declines. Maternal transfer of bioaccumulated contaminants to offspring may be an important and overlooked mechanism of impaired reproductive success that affects amphibian populations. Mercury (Hg) is of particular concern due to its ubiquity in the environment, known toxicity to other wildlife, and complex relationships with other elements, such as selenium (Se). The objectives of the present study were to describe the relationships between total Hg (THg), methlymercury (MMHg), and Se in three amphibian species (Plethodon cinereus, Eurycea bislineata cirrigera, and Bufo americanus) along a Hg-polluted river and floodplain, and to determine if B. americanus maternally transfers Hg and Se to its eggs in a tissue residue-dependent manner. Total Hg and MMHg concentrations in all species spanned two orders of magnitude between the reference and contaminated areas, while Se concentrations were generally low in all species at both sites. Strong positive relationships between THg and MMHg in tissues of all species were observed throughout. Both Hg and Se were maternally transferred from females to eggs in B. americanus, but the percentage of the females' Hg body burden transferred to eggs was low compared with Se. In addition, Hg concentrations appeared to positively influence the amount of Se transferred from female to eggs. The present study is the first to confirm a correlation between Hg concentrations in female carcass and eggs in amphibians and among the first to describe co-transference of Se and Hg in an anamniotic vertebrate. The results suggest future work is needed to determine whether maternal transfer of Hg has transgenerational implications for amphibian progeny.

  12. 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

  13. Development of a mobile application for amphibian species recognition

    Science.gov (United States)

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

    2014-02-01

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

  14. Bacterial community composition of anthropogenic biochar and Amazonian anthrosols assessed by 16S rRNA gene 454 pyrosequencing.

    Science.gov (United States)

    Taketani, Rodrigo Gouvêa; Lima, Amanda Barbosa; da Conceição Jesus, Ederson; Teixeira, Wenceslau Geraldes; Tiedje, James M; Tsai, Siu Mui

    2013-08-01

    Biochar (BC) is a common minor constituent of soils and is usually derived from the burning of wood materials. In the case of Amazonian dark earth (ADE) soils, the increased amount of this material is believed to be due to anthropogenic action by ancient indigenous populations. In this study, we use 16S rRNA gene pyrosequencing to assess the bacterial diversity observed in the BC found in ADEs as well as in the dark earth itself and the adjacent Acrisol. Samples were taken from two sites, one cultivated with manioc and one with secondary forest cover. Analyses revealed that the community structure found in each sample had unique features. At a coarse phylogenetic resolution, the most abundant phyla in all sequence libraries were Actinobacteria, Acidobacteria, Verrucomicrobia and Proteobacteria that were present in similar relative abundance across all samples. However, the class composition varied between them highlighting the difference between the Acrisol and the remaining samples. This result was also corroborated by the comparison of the OTU composition (at 97 % identity). Also, soil coverage has shown an effect over the community structure observed in all samples. This pattern was found to be significant through unweighted UniFrac as well as P tests. These results indicate that, although the ADEs are found in patches within the Acrisols, the contrasting characteristics found between them led to the development of significantly different communities. PMID:23743632

  15. Co-occurrence and community assembly in Amazonian palms (Arecaceae)

    DEFF Research Database (Denmark)

    Eiserhardt, Wolf L.; Balslev, Henrik; Kristiansen, Thea;

    Palms (Arecaceae) are a distinctive, diverse and ecologically important element of tropical rainforest. Often numerous palm species co-occur locally in "palm communities" that span all strata of the forest. In South America, the palm family has a centre of diversity in the western Amazon basin...

  16. Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)

    Science.gov (United States)

    Fyllas, N. M.; Gloor, E.; Mercado, L. M.; Sitch, S.; Quesada, C. A.; Domingues, T. F.; Galbraith, D. R.; Torre-Lezama, A.; Vilanova, E.; Ramírez-Angulo, H.; Higuchi, N.; Neill, D. A.; Silveira, M.; Ferreira, L.; Aymard C., G. A.; Malhi, Y.; Phillips, O. L.; Lloyd, J.

    2014-07-01

    Repeated long-term censuses have revealed large-scale spatial patterns in Amazon basin forest structure and dynamism, with some forests in the west of the basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth, designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR), has been developed. The model allows for within-stand variations in tree size distribution and key functional traits and between-stand differences in climate and soil physical and chemical properties. It runs at the stand level with four functional traits - leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) varying from tree to tree - in a way that replicates the observed continua found within each stand. We first applied the model to validate canopy-level water fluxes at three eddy covariance flux measurement sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for larger trees. At the stand level, simulations at 40 plots were used to explore the influence of climate and soil nutrient availability on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. On the other hand, all three measures of stand level productivity were positively related to both mean annual precipitation and soil nutrient status

  17. Survival of the amphibian chytrid fungus Batrachochytrium dendrobatidis on bare hands and gloves: hygiene implications for amphibian handling.

    Science.gov (United States)

    Mendez, Diana; Webb, Rebecca; Berger, Lee; Speare, Rick

    2008-11-20

    Hygiene protocols for handling amphibians in the field and in laboratories have been proposed to decrease the transmission of chytridiomycosis caused by infection with the amphibian chytrid fungus Batrachochytrium dendrobatidis, which is responsible for global amphibian declines. However, these protocols are mainly based on theoretical principles. The aim of this study was to develop an evidence-based approach to amphibian handling hygiene protocols by testing the survival of B. dendrobatidis on human hands and various gloves. Bare or gloved human fingers were exposed to cultured zoospores and zoosporangia of B. dendrobatidis. Survival of B. dendrobatidis on hands and gloves was tested for up to 10 min post-exposure by inoculation onto tryptone/gelatin hydrolysate/lactose (TGhL) agar plates. The effects of repeated hand washings with water and with 70% ethanol and of washing gloves with water were also tested. Bare human skin demonstrated a fungicidal effect on B. dendrobatidis by 2 min and killed 100% of cells by 6 min, but this killing effect was reduced by repeated washing with water and ethanol. Nitrile gloves killed all B. dendrobatidis on contact, but washing in water decreased this effect. Latex and polyethylene gloves had no killing effect, and B. dendrobatidis survived for over 6 min. The killing effect of vinyl gloves varied with brands and batches. These results support the use of an unused pair of gloves for each new amphibian handled in either the field or the laboratory, and if this is not possible, bare hands are a preferable, although imperfect, alternative to continual use of the same pair of gloves.

  18. Review and synthesis of the effects of climate change on amphibians.

    Science.gov (United States)

    Li, Yiming; Cohen, Jeremy M; Rohr, Jason R

    2013-06-01

    Considerable progress has been made in understanding the responses of amphibians to climate change, with successful research carried out on climate change-associated shifts in amphibian phenology, elevational distributions and amphibian-parasite interactions. We review and synthesize the literature on this topic, emphasizing acutely lethal, sublethal, indirect and positive effects of climate change on amphibians, and major research gaps. For instance, evidence is lacking on poleward shifts in amphibian distributions and on changes in body sizes and morphologies of amphibians in response to climate change. We have limited information on amphibian thermal tolerances, thermal preferences, dehydration breaths, opportunity costs of water conserving behaviors and actual temperature and moisture ranges amphibians experience. Even when much of this information is available, there remains little evidence that climate change is acutely lethal to amphibians. This suggests that if climate change is contributing to declines, it might be through effects that are not acutely lethal, indirect, or both, but evidence in support of this suggestion is necessary. In fact, evidence that climate change is directly contributing to amphibian declines is weak, partly because researchers have not often ruled out alternative hypotheses, such as chytrid fungus or climate-fungus interactions. Consequently, we recommend that amphibian-climate research shift from primarily inductive, correlational approach as to studies that evaluate alternative hypotheses for declines. This additional rigor will require interdisciplinary collaborations, estimates of costs and benefits of climate change to amphibian fitness and populations, and the integration of correlative field studies, experiments on 'model' amphibian species, and mathematical and functional, physiological models.

  19. Contingent Diversity on Anthropic Landscapes

    Directory of Open Access Journals (Sweden)

    William Balée

    2010-02-01

    Full Text Available Behaviorally modern human beings have lived in Amazonia for thousands of years. Significant dynamics in species turnovers due to human-mediated disturbance were associated with the ultimate emergence and expansion of agrarian technologies in prehistory. Such disturbances initiated primary and secondary landscape transformations in various locales of the Amazon region. Diversity in these locales can be understood by accepting the initial premise of contingency, expressed as unprecedented human agency and human history. These effects can be accessed through the archaeological record and in the study of living languages. In addition, landscape transformation can be demonstrated in the study of traditional knowledge (TK. One way of elucidating TK distinctions between anthropic and nonanthropic landscapes concerns elicitation of differential labeling of these landscapes and more significantly, elicitation of the specific contents, such as trees, occurring in these landscapes. Freelisting is a method which can be used to distinguish the differential species compositions of landscapes resulting from human-mediated disturbance vs. those which do not evince records of human agency and history. The TK of the Ka’apor Indians of Amazonian Brazil as revealed in freelisting exercises shows differentiation of anthropogenic from high forests as well as a recognition of diversity in the anthropogenic forests. This suggests that the agents of human-mediated disturbance and landscape transformation in traditional Amazonia encode diversity and contingency into their TK, which encoding reflects past cultural influence on landscape and society over time.

  20. Pesticide use and biodiversity conservation in the Amazonian agricultural frontier

    NARCIS (Netherlands)

    Schiesari, L.; Waichman, A.; Brock, T.C.M.; Adams, C.; Grillitsch, B.

    2013-01-01

    Agricultural frontiers are dynamic environments characterized by the conversion of native habitats to agriculture. Because they are currently concentrated in diverse tropical habitats, agricultural frontiers are areas where the largest number of species is exposed to hazardous land management practi

  1. Some aspects of the structure and the diversity of the arboreal vegetation of a forest of origin alluvial, not inundating of the Amazons River

    International Nuclear Information System (INIS)

    For the unaware observer, the Amazonian it is a great green and homogeneous mat, sometimes interrupted by serpentine currents of water that they break the continuity of the vegetable mantel. A detailed observation dispels that impression of homogeneity of the Amazon forest. On the contrary the Hylea is sprinkled of overflowed ambient, with numerous plants of thin shafts that conform a tangle, alternate of environments of plane topography, of soils well drainages, trees of thicker trunks, or set of hills of marked slopes, with narrow or wide summits and trees of diverse size and grosser. Equally the Amazonian region has environments that don't correspond to properly this forest, located on tables of gritty white of thin and low vegetation. The author treats topics as general aspects of the Amazonian area, characterization of landscape and forest structures

  2. Nematodes as indicators of shrimp farm impact on an amazonian estuary (Curuçá, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Virag Venekey

    2016-03-01

    Full Text Available Abstract Shrimp farming reduces demand on wild fishery stocks and avoids environmental damage resulting from fishing practices, however, it has the potential to affect the water quality if not properly managed. In this study the impacts of a shrimp farm in an Amazonian estuary were evaluated, focusing on changes in nematodes regarding taxonomic composition, richness, density and diversity. Sampling was conducted in August 2004 (dry season and January 2005 (rainy season in the river at stations situated upstream and downstream at different distances from the main source of farm effluent discharge. Thirty-eight genera were recorded with Terschellingia dominating in the dry season and Terschellingia, Daptonema, Ptycholaimellus and Gomphionema in the rainy season. Abundances were within the range recorded in other estuaries and together with genera richness and diversity showed a strong temporal pattern with significantly higher values in the rainy season. No clear patterns of changes were observed at the stations. Some signs of organic enrichment were detected but they were not yet intense, probably a consequence of the strong local hydrodynamics and the age of the shrimp farm, which was just starting its operation. We recommend that in future studies on farming impacts a combination of factors, beyond the physical and chemical parameters of the water and sediments or taxonomic refinement, should be taken into account - such as the duration of the operation of the farm, the area occupied by ponds and the farm's production. Furthermore, we also believe that nematodes are a useful tool for evaluating aquaculture impacts due to the ease of sampling and because they are organisms at the base of marine food chain.

  3. Trophic Strategies of a Non-Native and a Native Amphibian Species in Shared Ponds.

    Directory of Open Access Journals (Sweden)

    Olatz San Sebastián

    Full Text Available One of the critical factors for understanding the establishment, success and potential impact on native species of an introduced species is a thorough knowledge of how these species manage trophic resources. Two main trophic strategies for resource acquisition have been described: competition and opportunism. In the present study our objective was to identify the main trophic strategies of the non-native amphibian Discoglossus pictus and its potential trophic impact on the native amphibian Bufo calamita. We determine whether D. pictus exploits similar trophic resources to those exploited by the native B. calamita (competition hypothesis or alternative resources (opportunistic hypothesis. To this end, we analyzed the stable isotope values of nitrogen and carbon in larvae of both species, in natural ponds and in controlled laboratory conditions. The similarity of the δ15N and δ13C values in the two species coupled with isotopic signal variation according to pond conditions and niche partitioning when they co-occurred indicated dietary competition. Additionally, the non-native species was located at higher levels of trophic niches than the native species and B. calamita suffered an increase in its standard ellipse area when it shared ponds with D. pictus. These results suggest niche displacement of B. calamita to non-preferred resources and greater competitive capacity of D. pictus in field conditions. Moreover, D. pictus showed a broader niche than the native species in all conditions, indicating increased capacity to exploit the diversity of resources; this may indirectly favor its invasiveness. Despite the limitations of this study (derived from potential variability in pond isotopic signals, the results support previous experimental studies. All the studies indicate that D. pictus competes with B. calamita for trophic resources with potential negative effects on the fitness of the latter.

  4. Corticotropin-releasing factor enhances locomotion and medullary neuronal firing in an amphibian.

    Science.gov (United States)

    Lowry, C A; Rose, J D; Moore, F L

    1996-03-01

    Corticotropin-releasing factor (CRF) administration has been shown to act centrally to enhance locomotion in rats and amphibians. In the present study we used an amphibian, the roughskin newt (Taricha granulosa), to characterize changes in medullary neuronal activity associated with CRF-induced walking and swimming in animals chronically implanted with fine-wire microelectrodes. Neuronal activity was recorded from the raphe and adjacent reticular region of the rostral medulla. Under baseline conditions most of the recorded neurons showed low to moderate amounts of neuronal activity during periods of immobility and pronounced increases in firing that were time-locked with episodes of walking. These neurons sometimes showed further increases in discharge during swimming. Injections of CRF but not saline into the lateral ventricle produced a rapidly appearing increase in walking and pronounced changes (mostly increases) in firing rates of the medullary neurons. CRF produced diverse changes in patterns of firing in different neurons, but for these neurons as a group, the effects of CRF showed a close temporal association with the onset and expression of the peptide's effect on locomotion. In neurons that were active exclusively during movement prior to CRF treatment, the post-CRF increase in firing was evident during episodes of walking; in other neurons that also were spontaneously active during immobility prior to CRF infusion, post-CRF activity changes were evident during immobility as well as during episodes of locomotion. Thus, a principal effect of CRF was to potentiate the level of neuronal firing in a population of medullary neurons with locomotor-related properties. Due to the route of administration CRF may have acted on multiple central nervous system sites to enhance locomotion, but the results are consistent with neurophysiological effects involving medullary locomotion-regulating neurons.

  5. 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

  6. Trophic Strategies of a Non-Native and a Native Amphibian Species in Shared Ponds.

    Science.gov (United States)

    San Sebastián, Olatz; Navarro, Joan; Llorente, Gustavo A; Richter-Boix, Álex

    2015-01-01

    One of the critical factors for understanding the establishment, success and potential impact on native species of an introduced species is a thorough knowledge of how these species manage trophic resources. Two main trophic strategies for resource acquisition have been described: competition and opportunism. In the present study our objective was to identify the main trophic strategies of the non-native amphibian Discoglossus pictus and its potential trophic impact on the native amphibian Bufo calamita. We determine whether D. pictus exploits similar trophic resources to those exploited by the native B. calamita (competition hypothesis) or alternative resources (opportunistic hypothesis). To this end, we analyzed the stable isotope values of nitrogen and carbon in larvae of both species, in natural ponds and in controlled laboratory conditions. The similarity of the δ15N and δ13C values in the two species coupled with isotopic signal variation according to pond conditions and niche partitioning when they co-occurred indicated dietary competition. Additionally, the non-native species was located at higher levels of trophic niches than the native species and B. calamita suffered an increase in its standard ellipse area when it shared ponds with D. pictus. These results suggest niche displacement of B. calamita to non-preferred resources and greater competitive capacity of D. pictus in field conditions. Moreover, D. pictus showed a broader niche than the native species in all conditions, indicating increased capacity to exploit the diversity of resources; this may indirectly favor its invasiveness. Despite the limitations of this study (derived from potential variability in pond isotopic signals), the results support previous experimental studies. All the studies indicate that D. pictus competes with B. calamita for trophic resources with potential negative effects on the fitness of the latter. PMID:26101880

  7. Feeding habits of Sotalia fluviatilis in the Amazonian Estuary = Hábitos alimentares de Sotalia fluviatilis no estuário amazônico

    Directory of Open Access Journals (Sweden)

    Sandra Beltrán-Pedreros

    2006-10-01

    Full Text Available In this paper we present an analysis of the fifty S. fluviatilis feeding habits in the Amazonian Estuary. Animals were bycaught by the artisanal fishing fleet between 1996 and 2001. Feeding habits were analyzed by prey occurrence frequency (%F and number percentage and stomachs contents preys similarity between marine and freshwater fishspecies present in the Amazonian Estuary. Thirteen fish species were identified (%F= 86.6, the most significant families were Sciaenidae (32%, Trichiuridae (26% e Ariidae (16%, and four crustaceans species (%F=26. S. fluviatilis feeding habits did not differ bygender and in general, calves had higher prey diversity than juveniles and adults. The similarity was high (0.89 between estuarine S. fluviatilis feeding habits and the fishes speciespresent in the Amazonian Estuary when the environment is mostly marine.Objetivou-se descrever e analisar os hábitos alimentares de 50 golfinhos Sotalia fluviatilis capturados acidentalmente na frota pesqueira artesanal do Estuário Amazônico entre 1996 e 2001. As presas foram identificadas e calculadas a freqüência de ocorrência e numérica; testada a similaridade entre a diversidade de presas dos conteúdos e a diversidade de peixes marinhos e de água doce do estuário e, comparados os hábitos alimentares por sexo e categoria de maturidade. Ocorreram 13 espécies de peixes (86,6% onde as famíliasSciaenidae (32%, Trichiuridae (26% e Ariidae (16% foram mais representativas e, quatro espécies de crustáceos (26%. A espécie não apresentou diferenças nos hábitos alimentares entre sexos, mas, os filhotes tiveram maior diversidade de presas que jovens e adultos.Finalmente, houve maior similaridade (0.89 entre a diversidade de presas de S. fluviatilis e as espécies de peixes quando o estuário apresenta características marinhas.

  8. 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.

  9. 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. [...

  10. 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.

  11. Congenital malformations of the vertebral column in ancient amphibians.

    Science.gov (United States)

    Witzmann, F; Rothschild, B M; Hampe, O; Sobral, G; Gubin, Y M; Asbach, P

    2014-04-01

    Temnospondyls, the largest group of Palaeozoic and Mesozoic amphibians, primitively possess rhachitomous vertebrae with multipartite centra (consisting of one horse-shoe-shaped inter- and paired pleurocentra). In a group of temnospondyls, the stereospondyls, the intercentra became pronounced and disc-like, whereas the pleurocentra were reduced. We report the presence of congenital vertebral malformations (hemi, wedge and block vertebrae) in Permian and Triassic temnospondyls, showing that defects of formation and segmentation in the tetrapod vertebral column represent a fundamental failure of somitogenesis that can be followed throughout tetrapod evolution. This is irrespective of the type of affected vertebra, that is, rhachitomous or stereospondylous, and all components of the vertebra can be involved (intercentrum, pleurocentrum and neural arch), either together or independently on their own. This is the oldest known occurrence of wedge vertebra and congenital block vertebra described in fossil tetrapods. The frequency of vertebral congenital malformations in amphibians appears unchanged from the Holocene.

  12. Habitat heterogeneity drives the host-diversity-begets-parasite-diversity relationship: evidence from experimental and field studies.

    Science.gov (United States)

    Johnson, Pieter T J; Wood, Chelsea L; Joseph, Maxwell B; Preston, Daniel L; Haas, Sarah E; Springer, Yuri P

    2016-07-01

    Despite a century of research into the factors that generate and maintain biodiversity, we know remarkably little about the drivers of parasite diversity. To identify the mechanisms governing parasite diversity, we combined surveys of 8100 amphibian hosts with an outdoor experiment that tested theory developed for free-living species. Our analyses revealed that parasite diversity increased consistently with host diversity due to habitat (i.e. host) heterogeneity, with secondary contributions from parasite colonisation and host abundance. Results of the experiment, in which host diversity was manipulated while parasite colonisation and host abundance were fixed, further reinforced this conclusion. Finally, the coefficient of host diversity on parasite diversity increased with spatial grain, which was driven by differences in their species-area curves: while host richness quickly saturated, parasite richness continued to increase with neighbourhood size. These results offer mechanistic insights into drivers of parasite diversity and provide a hierarchical framework for multi-scale disease research.

  13. 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...

  14. 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...

  15. 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

  16. Landscape-stream interactions and habitat conservation for amphibians.

    Science.gov (United States)

    Ficetola, Gentile Francesco; Marziali, Laura; Rossaro, Bruno; De Bernardi, Fiorenza; Padoa-Schioppa, Emilio

    2011-06-01

    Semiaquatic organisms depend on the features of both water bodies and landscapes; the interplay between terrestrial and aquatic systems might influence the semiaquatic communities, determining the scale at which management would be more effective. However, the consequences of such interplay are not frequently quantified, particularly at the community level. We analyzed the distribution of amphibians to evaluate whether the influence of landscape features on freshwater ecosystems can have indirect consequences at both the species and community level. We surveyed 74 streams in northern Italy to obtain data on breeding amphibians, water, and microhabitat features; we also measured features of surrounding landscapes. We used an information-theoretic approach and structural equation models to compare hypotheses on causal relationships between species distribution and variables measured at multiple levels. We also used a constrained redundancy analyses to evaluate causal relationships between multivariate descriptors of habitat features and community composition. Distribution of Salamandra salamandra was related to landscape, hydrological, and water characteristics: salamanders were more frequent in permanent streams with low phosphate concentration within natural landscapes. Water characteristics were dependent on landscape: streams in natural landscapes had less phosphates. Landscape influenced the salamander both directly and indirectly through its influence on phosphates. Community structure was determined by both landscape and water characteristics. Several species were associated with natural landscapes, and with particular water characteristics. Landscape explained a significant proportion of variability of water characteristics; therefore it probably had indirect effects on community. Upland environments play key roles for amphibians, for example, as the habitat of adults, but upland environments also have indirect effects on the aquatic life stages, mediated

  17. 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

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  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. 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

  4. Optimizing protection efforts for amphibian conservation in Mediterranean landscapes

    Science.gov (United States)

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

    2013-05-01

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

  5. Interventions for reducing extinction risk in chytridiomycosis-threatened amphibians.

    Science.gov (United States)

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

    2014-10-01

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

  6. Cardiac performance correlates of relative heart ventricle mass in amphibians.

    Science.gov (United States)

    Kluthe, Gregory J; Hillman, Stanley S

    2013-08-01

    This study used an in situ heart preparation to analyze the power output and stroke work of spontaneously beating hearts of four anurans (Rhinella marina, Lithobates catesbeianus, Xenopus laevis, Pyxicephalus edulis) and three urodeles (Necturus maculosus, Ambystoma tigrinum, Amphiuma tridactylum) that span a representative range of relative ventricle mass (RVM) found in amphibians. Previous research has documented that RVM correlates with dehydration tolerance and maximal aerobic capacity in amphibians. The power output (mW g(-1) ventricle mass) and stroke work (mJ g(-1) ventricle muscle mass) were independent of RVM and were indistinguishable from previously published results for fish and reptiles. RVM was significantly correlated with maximum power output (P max, mW kg(-1) body mass), stroke volume, cardiac output, afterload pressure (P O) at P max, and preload pressure (P I) at P max. P I at P max and P O at P max also correlated very closely with each other. The increases in both P I and P O at maximal power outputs in large hearts suggest that concomitant increases in blood volume and/or increased modulation of vascular compliance either anatomically or via sympathetic tone on the venous vasculature would be necessary to achieve P max in vivo. Hypotheses for variation in RVM and its concomitant increased P max in amphibians are developed.

  7. Independent evolution of the sexes promotes amphibian diversification.

    Science.gov (United States)

    De Lisle, Stephen P; Rowe, Locke

    2015-03-22

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

  8. 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

  9. The influence of different land uses on the structure of archaeal communities in Amazonian anthrosols based on 16S rRNA and amoA genes.

    Science.gov (United States)

    Taketani, Rodrigo Gouvêa; Tsai, Siu Mui

    2010-05-01

    Soil from the Amazonian region is usually regarded as unsuitable for agriculture because of its low organic matter content and low pH; however, this region also contains extremely rich soil, the Terra Preta Anthrosol. A diverse archaeal community usually inhabits acidic soils, such as those found in the Amazon. Therefore, we hypothesized that this community should be sensitive to changes in the environment. Here, the archaeal community composition of Terra Preta and adjacent soil was examined in four different sites in the Brazilian Amazon under different anthropic activities. The canonical correspondence analysis of terminal restriction fragment length polymorphisms has shown that the archaeal community structure was mostly influenced by soil attributes that differentiate the Terra Preta from the adjacent soil (i.e., pH, sulfur, and organic matter). Archaeal 16S rRNA gene clone libraries indicated that the two most abundant genera in both soils were Candidatus nitrosphaera and Canditatus nitrosocaldus. An ammonia monoxygenase gene (amoA) clone library analysis indicated that, within each site, there was no significant difference between the clone libraries of Terra Preta and adjacent soils. However, these clone libraries indicated there were significant differences between sites. Quantitative PCR has shown that Terra Preta soils subjected to agriculture displayed a higher number of amoA gene copy numbers than in adjacent soils. On the other hand, soils that were not subjected to agriculture did not display significant differences on amoA gene copy numbers between Terra Preta and adjacent soils. Taken together, our findings indicate that the overall archaeal community structure in these Amazonian soils is determined by the soil type and the current land use. PMID:20204349

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

    Science.gov (United States)

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

    2016-01-01

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

  11. 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).

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

    Science.gov (United States)

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

    2007-05-15

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

  13. 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

  14. Occurrence of Cryptosporidium spp. in Antillean manatees (Trichechus manatus) and Amazonian manatees (Trichechus inunguis) from Brazil.

    Science.gov (United States)

    Borges, Joāo Carlos Gomes; Alves, Leucio Câmara; Faustino, Maria Aparecida da Gloria; Marmontel, Miriam

    2011-12-01

    Infections by Cryptosporidium spp. in aquatic mammals is a major concern due to the possibility of the waterborne transmission of oocysts. The aim of the present study was to report the occurrence of Cryptosporidium spp. in Antillean manatees (Trichechus manatus) and Amazonian manatees (Trichechus inunguis) from Brazil. Fecal samples were collected and processed using Kinyoun's method. Positive samples were also submitted to the direct immunofluorescence test. The results revealed the presence of Cryptosporidium spp. oocysts in 12.5% (17/136) of the material obtained from the Antillean manatees and in 4.3% (05/115) of the samples from the Amazonian manatees. Cryptosporidium spp. infection was more prevalent in captive animals than in free-ranging specimens. PMID:22204053

  15. Phenolic constituents and antioxidant activity of geopropolis from two species of amazonian stingless bees

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ellen Cristina Costa da; Muniz, Magno Perea; Nunomura, Rita de Cassia Saraiva, E-mail: ellensilva@yahoo.com.br [Departamento de Quimica, Instituto de Ciencias Exatas, Universidade Federal do Amazonas, Manaus, AM (Brazil); Nunomura, Sergio Massayoshi [Departamento de Produtos Naturais, Instituto Nacional de Pesquisas da Amazonia, Manaus, AM (Brazil); Zilse, Gislene Almeida Carvalho [Departamento de Biodiversidade, Instituto Nacional de Pesquisas da Amazonia, Manaus, AM (Brazil)

    2013-09-01

    We investigated the phenolic constituents and antioxidant activity of geopropolis from two species of stingless Amazonian bees, Melipona interrupta and Melipona seminigra. The chemical investigation of geopropolis from Melipona interrupta led to the isolation of 5,7,4'-trihydroxyflavonone, 3,5,6,7,4'-pentahydroxyflavonol, naringenine-4'-O-{beta}-D-glucopyranoside and myricetin-3-O-{beta}-D-glucopyranoside. Their structures were assigned based on spectroscopic analyses, including two-dimensional NMR techniques. Antioxidant activity of methanol and ethanol extracts of M. interrupta and M. seminigra were measured using the 1,2-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay. This is also the first work reporting the chemical investigation of stingless bee species from the Amazonian region. (author)

  16. Occurrence of Cryptosporidium spp. in Antillean manatees (Trichechus manatus) and Amazonian manatees (Trichechus inunguis) from Brazil.

    Science.gov (United States)

    Borges, Joāo Carlos Gomes; Alves, Leucio Câmara; Faustino, Maria Aparecida da Gloria; Marmontel, Miriam

    2011-12-01

    Infections by Cryptosporidium spp. in aquatic mammals is a major concern due to the possibility of the waterborne transmission of oocysts. The aim of the present study was to report the occurrence of Cryptosporidium spp. in Antillean manatees (Trichechus manatus) and Amazonian manatees (Trichechus inunguis) from Brazil. Fecal samples were collected and processed using Kinyoun's method. Positive samples were also submitted to the direct immunofluorescence test. The results revealed the presence of Cryptosporidium spp. oocysts in 12.5% (17/136) of the material obtained from the Antillean manatees and in 4.3% (05/115) of the samples from the Amazonian manatees. Cryptosporidium spp. infection was more prevalent in captive animals than in free-ranging specimens.

  17. The origin and nature of macroecological patterns in amphibians: old questions, novel approaches

    Directory of Open Access Journals (Sweden)

    Sidney F. Gouveia

    2013-12-01

    Full Text Available The role of physiological parameters as determinants of macroscale patterns is still widely disputed. Using amphibians as a model, I revisited three fundamental themes in macroecology from a physiological perspective: the global diversity gradient, ecogeographical rules and the evolution of the climatic niche at physiological and macroecological scales. To do this, I used a variety of data types, performed a number of spatial and phylogenetic analyses and proposed novel applications for some methods. I also provided support for some well-established hypotheses regarding the physiological determinants of species diversity and trait variation across space, while revealing other lesser known patterns and the possible processes underlying species’ distributions and niche evolution. I emphasize the need for a novel integration of theoretical and methodological approaches to improve the analysis of broad-scale ecological processes, in particular those related to the fundamental features (e.g. physiology of species. I also highlight the strategic role of macroecology in this quest, especially in the face of ongoing environmental changes. 

  18. Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

    OpenAIRE

    Nilvanda dos Santos Magalhães; Ricardo Antonio Marenco; Miguel Angelo Branco Camargo

    2014-01-01

    Most Amazonian soils are highly weathered and poor in nutrients. Therefore, photosynthesis and plant growth should positively respond to the addition of mineral nutrients. Surprisingly, no study has been carried out in situ in the central Amazon to address this issue for juvenile trees. The objective of this study was to determine how photosynthetic rates and growth of tree saplings respond to the addition of mineral nutrients, to the variation in leaf area index of the forest canopy, and to ...

  19. Legacies of Amazonian dark earths on forest composition, structure and dynamics

    OpenAIRE

    Quintero Vallejo, E.M.

    2015-01-01

    Summary Amazonian forest is seen as the archetype of pristine forests, untouched by humans, but this romantic view is far from reality. In recent years, there is increasing evidence of long and extensive landscape modification by humans. Processes of permanent inhabitation, expansion and retreat of human populations have not always been obvious in those ecosystems, leaving sometimes weak and overlooked imprints in the landscape. An example of one of these inconspicuous alterations are the mod...

  20. Scalar turbulent behavior in the roughness sublayer of an Amazonian forest

    OpenAIRE

    Zahn, Einara; Dias, Nelson L.; Araújo, Alessandro; Sá, Leonardo; Söergel, Matthias; Trebs, Ivonne; Wolff, Stefan; Manzi, Antônio

    2016-01-01

    An important current problem in micrometeorology is the characterization of turbulence in the roughness sublayer (RSL), where most of the measurements above tall forests are made. There, scalar turbulent fluctuations display significant departures from the predictions of Monin–Obukhov similarity theory (MOST). In this work, we analyze turbulence data of virtual temperature, carbon dioxide and water vapor in the RSL above an Amazonian Forest (with a canopy height of 40 m), measured at 39.4 ...

  1. OCCURRENCE OF Charybdis hellerii (Milne Edwards, 1867 (CRUSTACEA, DECAPODA, PORTUNIDAE IN AN AMAZONIAN ESTUARY.

    Directory of Open Access Journals (Sweden)

    Alessandra Batista Bentes

    2013-12-01

    Full Text Available For the first time specimens of Charybdis hellerii (Milne Edwards 1867, an Indo Pacific specie, were caught in Amazon estuary, Bragança, Pará, North of Brazil. Palavras-chave: Crustacea, Charybdis hellerii , Amazonian Estuary. DOI: http://dx.doi.org/10.18561/2179-5746/biotaamazonia.v3n3p181-184

  2. Optimizing Sampling Design to Deal with Mist-Net Avoidance in Amazonian Birds and Bats

    OpenAIRE

    João Tiago Marques; Ramos Pereira, Maria J.; Marques, Tiago A.; Carlos David Santos; Joana Santana; Pedro Beja; Palmeirim, Jorge M.

    2013-01-01

    Mist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures of Amazonian birds and bats with mist nets set at the same location for four consecutive days. We also evaluated how net avoidance influences the efficiency of surveys under different logistic scen...

  3. Ecomorphological patterns of the fishes inhabiting the tide pools of the Amazonian Coastal Zone, Brazil

    OpenAIRE

    Bruno Eleres Soares; Tiago Octavio Begot Ruffeil; Luciano Fogaça de Assis Montag

    2013-01-01

    The present study was based on the identification of the ecomorphological patterns that characterize the fish species found in tide pools in the Amazonian Coastal Zone (ACZ) in the Pará State, Brazil. Representatives of 19 species were collected during two field campaigns in 2011. The dominance, residence status, and trophic guild of each species were established, and morphometric data were obtained for up to 10 specimens of each species. A total of 23 ecomorphological attributes related to l...

  4. Wood decomposition in Amazonian hydropower reservoirs: An additional source of greenhouse gases

    Science.gov (United States)

    Abril, Gwenaël; Parize, Marcelo; Pérez, Marcela A. P.; Filizola, Naziano

    2013-07-01

    Amazonian hydroelectric reservoirs produce abundant carbon dioxide and methane from large quantities of flooded biomass that decompose anaerobically underwater. Emissions are extreme the first years after impounding and progressively decrease with time. To date, only water-to-air fluxes have been considered in these estimates. Here, we investigate in two Amazonian reservoirs (Balbina and Petit Saut) the fate of above water standing dead trees, by combining a qualitative analysis of wood state and density through time and a quantitative analysis of the biomass initially flooded. Dead wood was much more decomposed in the Balbina reservoir 23 years after flooding than in the Petit Saut reservoir 10 years after flooding. Termites apparently played a major role in wood decomposition, occurring mainly above water, and resulting in a complete conversion of this carbon biomass into CO2 and CH4 at a timescale much shorter than reservoir operation. The analysis of pre-impounding wood biomass reveals that above-water decomposition in Amazonian reservoirs is a large, previously unrecognized source of carbon emissions to the atmosphere, representing 26-45% of the total reservoir flux integrated over 100 years. Accounting for both below- and above-water fluxes, we could estimate that each km2 of Amazonian forest converted to reservoir would emit over 140 Gg CO2-eq in 100 years. Hydropower plants in the Amazon should thus generate 0.25-0.4 MW h per km2 flooded area to produce lower greenhouse gas emissions than gas power plants. They also have the disadvantage to emit most of their greenhouse gases the earliest years of operation.

  5. Ritualistic use of the holly Ilex guayusa by Amazonian Jívaro Indians.

    Science.gov (United States)

    Lewis, W H; Kennelly, E J; Bass, G N; Wedner, H J; Elvin-Lewis, M P; Fast, D

    1991-01-01

    In Amazonian Peru and Ecuador leaf decoctions of the rainforest holly Ilex guayusa with high caffeine concentrations are used as a morning stimulant. After daily ingestion, ritualistic vomiting by male Achuar Indians, better known as Jívaros, reduces excessive caffeine intake, so that blood levels of caffeine and biotransformed dimethylxanthines do not cause undesirable CNS and other effects. Emesis is learned and apparently not due to emetic compounds. PMID:1682531

  6. Physical growth of the shuar: Height, Weight, and BMI references for an indigenous amazonian population

    OpenAIRE

    Urlacher, SS; Blackwell, AD; Liebert, MA; Madimenos, FC; Cepon-Robins, TJ; Gildner, TE; Snodgrass, JJ; Sugiyama, LS

    2016-01-01

    © 2015 Wiley Periodicals, Inc. Objectives: Information concerning physical growth among small-scale populations remains limited, yet such data are critical to local health efforts and to foster basic understandings of human life history and variation in childhood development. Using a large dataset and robust modeling methods, this study aims to describe growth from birth to adulthood among the indigenous Shuar of Amazonian Ecuador. Methods: Mixed-longitudinal measures of height, weight, and b...

  7. Endocannabinoids affect the reproductive functions in teleosts and amphibians.

    Science.gov (United States)

    Cottone, E; Guastalla, A; Mackie, K; Franzoni, M F

    2008-04-16

    Following the discovery in the brain of the bonyfish Fugu rubripes of two genes encoding for type 1 cannabinoid receptors (CB1A and CB1B), investigations on the phylogeny of these receptors have indicated that the cannabinergic system is highly conserved. Among the multiple functions modulated by cannabinoids/endocannabinoids through the CB1 receptors one of the more investigated is the mammalian reproduction. Therefore, since studies performed in animal models other than mammals might provide further insight into the biology of these signalling molecules, the major aim of the present paper was to review the comparative data pointing toward the endocannabinoid involvement in the reproductive control of non-mammalian vertebrates, namely bonyfish and amphibians. The expression and distribution of CB1 receptors were investigated in the CNS and gonads of two teleosts, Pelvicachromis pulcher and Carassius auratus as well as in the anuran amphibians Xenopus laevis and Rana esculenta. In general the large diffusion of neurons targeted by cannabinoids in both fish and amphibian forebrain indicate endocannabinoids as pivotal local messengers in several neural circuits involved in either sensory integrative activities, like the olfactory processes (in amphibians) and food response (in bonyfish), or neuroendocrine machinery (in both). By using immunohistochemistry for CB1 and GnRH-I, the codistribution of the two signalling molecules was found in the fish basal telencephalon and preoptic area, which are key centers for gonadotropic regulation in all vertebrates. A similar topographical codistribution was observed also in the septum of the telencephalon in Rana esculenta and Xenopus laevis. Interestingly, the double standard immunofluorescence on the same brain section, aided with a laser confocal microscope, showed that in anurans a subset of GnRH-I neurons exhibited also the CB1 immunostaining. The fact that CB1-LI-IR was found indeed in the FSH gonadotrophs of the Xenopus

  8. Controls of Nazca ridge subduction on the Amazonian foreland basin geometry

    Science.gov (United States)

    Espurt, N.; Baby, P.; Brusset, S.; Roddaz, M.; Hermoza, W.; Regard, V.; Martinod, J.; Bolaños, R.

    2006-12-01

    In the central Andes, the Nazca ridge subduction imprints can be tracked on the eastern side of the Andes. The western part of the Amazonian basin is currently an atypical foreland basin because the Amazonian foreland basin 3-D geometry does not follow the foreland basin system model of DeCelles and Giles [1]. The Amazonian foreland basin consists of two main subsiding basins separated by the NE-SW trending structural/morphologic Fitzcarrald Arch. Geomorphic and lithospheric data provide evidence that the large wavelength Fitzcarrald Arch uplift at 750 kilometers ahead of the trench results from the Nazca ridge flat subduction. The flexure of the South American lithosphere is overcompensated by the buoyancy of the Nazca ridge impeaching a four-component foreland basin system. The recent deformations of the Amazon basin are characterized by vertical motions as recorded by the radial modern drainage network and the deformation of Pliocene to recent fluvial deposits on both sides of the arch, according to the kinematics of the Nazca ridge subduction. In addition, analogue lithospheric experiments similarly show that the ridge buoyancy induces uplift above the flat-slab segment in the foreland basin separating two subsiding sub-basins resulting from the flexure of the continental lithosphere. [1] DeCelles, P.G., and Giles, K.A.(1996)Foreland basin systems: Basin Research, 8, 105-123.

  9. Estimating the global conservation status of more than 15,000 Amazonian tree species

    Science.gov (United States)

    ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.; Laurance, William F.; Peres, Carlos A.; Guevara, Juan Ernesto; Salomão, Rafael P.; Castilho, Carolina V.; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E.; Phillips, Oliver L.; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R.; Honorio Coronado, Euridice N.; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L.; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G. W.; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S.; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F.; Mogollón, Hugo F.; Piedade, Maria Teresa Fernandez; Aymard C., Gerardo A.; Comiskey, James A.; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W.; Jimenez, Eliana M.; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R.; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R.; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R.; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R.; Silva, Natalino; Vela, César I. A.; Vos, Vincent A.; Zent, Eglée L.; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A.; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R.; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N.; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H.; Gamarra, Luis Valenzuela

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442

  10. Estimating the global conservation status of more than 15,000 Amazonian tree species.

    Science.gov (United States)

    Ter Steege, Hans; Pitman, Nigel C A; Killeen, Timothy J; Laurance, William F; Peres, Carlos A; Guevara, Juan Ernesto; Salomão, Rafael P; Castilho, Carolina V; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E; Phillips, Oliver L; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R; Honorio Coronado, Euridice N; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G W; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F; Mogollón, Hugo F; Piedade, Maria Teresa Fernandez; Aymard C, Gerardo A; Comiskey, James A; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Jimenez, Eliana M; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vela, César I A; Vos, Vincent A; Zent, Eglée L; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H; Gamarra, Luis Valenzuela

    2015-11-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world's >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442

  11. Siliceous spicules enhance fracture-resistance and stiffness of pre-colonial Amazonian ceramics

    Science.gov (United States)

    Natalio, Filipe; Corrales, Tomas P.; Wanka, Stephanie; Zaslansky, Paul; Kappl, Michael; Lima, Helena Pinto; Butt, Hans-Jürgen; Tremel, Wolfgang

    2015-08-01

    Pottery was a traditional art and technology form in pre-colonial Amazonian civilizations, widely used for cultural expression objects, utensils and as cooking vessels. Abundance and workability of clay made it an excellent choice. However, inferior mechanical properties constrained their functionality and durability. The inclusion of reinforcement particles is a possible route to improve its resistance to mechanical and thermal damage. The Amazonian civilizations incorporated freshwater tree sponge spicules (cauixí) into the clay presumably to prevent shrinkage and crack propagation during drying, firing and cooking. Here we show that isolated siliceous spicules are almost defect-free glass fibres with exceptional mechanical stability. After firing, the spicule Young’s modulus increases (from 28 ± 5 GPa to 46 ± 8 GPa) inferring a toughness increment. Laboratory-fabricated ceramic models containing different inclusions (sand, glass-fibres, sponge spicules) show that mutually-oriented siliceous spicule inclusions prevent shrinkage and crack propagation leading to high stiffness clays (E = 836 ± 3 MPa). Pre-colonial amazonian potters were the first civilization known to employ biological materials to generate composite materials with enhanced fracture resistance and high stiffness in the history of mankind.

  12. Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests

    International Nuclear Information System (INIS)

    Resolving the debate surrounding the nature and controls of seasonal variation in the structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the Sunlight-rich dry season. Satellite data also indicated higher greenness level, a proven surrogate of photosynthetic carbon fixation, and leaf area during the dry season relative to the wet season. Some recent reports suggest that rainforests display no seasonal variations and the previous results were satellite measurement artefacts. Therefore, here we re-examine several years of data from three sensors on two satellites under a range of sun positions and satellite measurement geometries and document robust evidence for a seasonal cycle in structure and greenness of wet equatorial Amazonian rainforests. This seasonal cycle is concordant with independent observations of solar radiation. We attribute alternative conclusions to an incomplete study of the seasonal cycle, i.e. the dry season only, and to prognostications based on a biased radiative transfer model. Consequently, evidence of dry season greening in geometry corrected satellite data was ignored and the absence of evidence for seasonal variation in lidar data due to noisy and saturated signals was misinterpreted as evidence of the absence of changes during the dry season. Our results, grounded in the physics of radiative transfer, buttress previous reports of dry season increases in leaf flushing, litterfall, photosynthesis and evapotranspiration in well-hydrated Amazonian rainforests. (letter)

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

    Science.gov (United States)

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

    2016-10-01

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

  14. Comparative acute and chronic sensitivity of fish and amphibians: a critical review of data.

    Science.gov (United States)

    Weltje, Lennart; Simpson, Peter; Gross, Melanie; Crane, Mark; Wheeler, James R

    2013-04-01

    The relative sensitivity of amphibians to chemicals in the environment, including plant protection product active substances, is the subject of ongoing scientific debate. The objective of this study was to compare systematically the relative sensitivity of amphibians and fish to chemicals. Acute and chronic toxicity data were obtained from the U.S. Environmental Protection Agency (U.S. EPA) ECOTOX database and were supplemented with data from the scientific and regulatory literature. The overall outcome is that fish and amphibian toxicity data are highly correlated and that fish are more sensitive (both acute and chronic) than amphibians. In terms of acute sensitivity, amphibians were between 10- and 100-fold more sensitive than fish for only four of 55 chemicals and more than 100-fold more sensitive for only two chemicals. However, a detailed inspection of these cases showed a similar acute sensitivity of fish and amphibians. Chronic toxicity data for fish were available for 52 chemicals. Amphibians were between 10- and 100-fold more sensitive than fish for only two substances (carbaryl and dexamethasone) and greater than 100-fold more sensitive for only a single chemical (sodium perchlorate). The comparison for carbaryl was subsequently determined to be unreliable and that for sodium perchlorate is a potential artifact of the exposure medium. Only a substance such as dexamethasone, which interferes with a specific aspect of amphibian metamorphosis, might not be detected using fish tests. However, several other compounds known to influence amphibian metamorphosis were included in the analysis, and these did not affect amphibians disproportionately. These analyses suggest that additional amphibian testing is not necessary during chemical risk assessment.

  15. 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...

  16. Contribution of Multiple Inter-Kingdom Horizontal Gene Transfers to Evolution and Adaptation of Amphibian-Killing Chytrid, Batrachochytrium dendrobatidis

    Science.gov (United States)

    Sun, Baofa; Li, Tong; Xiao, Jinhua; Liu, Li; Zhang, Peng; Murphy, Robert W.; He, Shunmin; Huang, Dawei

    2016-01-01

    Amphibian populations are experiencing catastrophic declines driven by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Although horizontal gene transfer (HGT) facilitates the evolution and adaptation in many fungi by conferring novel function genes to the recipient fungi, inter-kingdom HGT in Bd remains largely unexplored. In this study, our investigation detects 19 bacterial genes transferred to Bd, including metallo-beta-lactamase and arsenate reductase that play important roles in the resistance to antibiotics and arsenates. Moreover, three probable HGT gene families in Bd are from plants and one gene family coding the ankyrin repeat-containing protein appears to come from oomycetes. The observed multi-copy gene families associated with HGT are probably due to the independent transfer events or gene duplications. Five HGT genes with extracellular locations may relate to infection, and some other genes may participate in a variety of metabolic pathways, and in doing so add important metabolic traits to the recipient. The evolutionary analysis indicates that all the transferred genes evolved under purifying selection, suggesting that their functions in Bd are similar to those of the donors. Collectively, our results indicate that HGT from diverse donors may be an important evolutionary driver of Bd, and improve its adaptations for infecting and colonizing host amphibians.

  17. Correlation between the habitats productivity and species richness (amphibians and reptiles) in Portugal through remote sensed data

    Science.gov (United States)

    Teodoro, A. C.; Sillero, N.; Alves, S.; Duarte, L.

    2013-10-01

    Several biogeographic theories propose that the species richness depends on the structure and ecosystems diversity. The habitat productivity, a surrogate for these variables, can be evaluated through satellite imagery, namely using vegetation indexes (e.g. NDVI). We analyzed the correlation between species richness (from the Portuguese Atlas of Amphibians and Reptiles) and NDVI (from Landsat, MODIS, and Vegetation images). The species richness database contains more than 80000 records, collected from bibliographic sources (at 1 or 10 km of spatial resolution) and fieldwork sampling stations (recorded with GPS devices). Several study areas were chosen for Landsat images (three subsets), and all Portugal for MODIS and Vegetation images. The Landsat subareas had different climatic and habitat characteristics, located in the north, center and south of Portugal. Different species richness datasets were used depending on the image spatial resolution: data with metric resolution were used for Landsat, and with 1 km resolution, for MODIS and Vegetation images. The NDVI indexes and all the images were calculated/processed in an open source software (Quantum GIS). Several plug-ins were applied in order to automatize several procedures. We did not find any correlation between the species richness of amphibians and reptiles (not even after separating both groups by species of Atlantic and Mediterranean affinity) and the NDVI calculated with Landsat, MODIS and Vegetation images. Our results may fail to find a relationship because as the species richness is not correlated with only one variable (NDVI), and thus other environmental variables must be considered.

  18. Contribution of Multiple Inter-kingdom Horizontal Gene Transfers to Evolution and Adaptation of Amphibian-killing Chytrid, Batrachochytrium dendrobatidis

    Directory of Open Access Journals (Sweden)

    Baofa Sun

    2016-08-01

    Full Text Available Amphibian populations are experiencing catastrophic declines driven by the fungal pathogen Batrachochytrium dendrobatidis (Bd. Although horizontal gene transfer (HGT facilitates the evolution and adaptation in many fungi by conferring novel function genes to the recipient fungi, inter-kingdom HGT in Bd remains largely unexplored. In this study, our investigation detects 19 bacterial genes transferred to Bd, including metallo-beta-lactamase and arsenate reductase that play important roles in the resistance to antibiotics and arsenates. Moreover, three probable HGT gene families in Bd are from plants and one gene family coding the ankyrin repeat-containing protein appears to come from oomycetes. The observed multi-copy gene families associated with HGT are probably due to the independent transfer events or gene duplications. Five HGT genes with extracellular locations may relate to infection, and some other genes may participate in a variety of metabolic pathways, and in doing so add important metabolic traits to the recipient. The evolutionary analysis indicates that all the transferred genes evolved under purifying selection, suggesting that their functions in Bd are similar to those of the donors. Collectively, our results indicate that HGT from diverse donors may be an important evolutionary driver of Bd, and improve its adaptations for infecting and colonizing host amphibians.

  19. Contribution of Multiple Inter-Kingdom Horizontal Gene Transfers to Evolution and Adaptation of Amphibian-Killing Chytrid, Batrachochytrium dendrobatidis

    Science.gov (United States)

    Sun, Baofa; Li, Tong; Xiao, Jinhua; Liu, Li; Zhang, Peng; Murphy, Robert W.; He, Shunmin; Huang, Dawei

    2016-01-01

    Amphibian populations are experiencing catastrophic declines driven by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Although horizontal gene transfer (HGT) facilitates the evolution and adaptation in many fungi by conferring novel function genes to the recipient fungi, inter-kingdom HGT in Bd remains largely unexplored. In this study, our investigation detects 19 bacterial genes transferred to Bd, including metallo-beta-lactamase and arsenate reductase that play important roles in the resistance to antibiotics and arsenates. Moreover, three probable HGT gene families in Bd are from plants and one gene family coding the ankyrin repeat-containing protein appears to come from oomycetes. The observed multi-copy gene families associated with HGT are probably due to the independent transfer events or gene duplications. Five HGT genes with extracellular locations may relate to infection, and some other genes may participate in a variety of metabolic pathways, and in doing so add important metabolic traits to the recipient. The evolutionary analysis indicates that all the transferred genes evolved under purifying selection, suggesting that their functions in Bd are similar to those of the donors. Collectively, our results indicate that HGT from diverse donors may be an important evolutionary driver of Bd, and improve its adaptations for infecting and colonizing host amphibians. PMID:27630622

  20. Tide distortion and attenuation in an Amazonian tidal river

    Directory of Open Access Journals (Sweden)

    Paulo T. A. Freitas

    2012-12-01

    Full Text Available The present study seeks to evaluate tidal propagation in the Guamá-Capim river system, in the Amazonian region, considering hydrodynamic and geomorphological aspects. Available data sets on fluvial discharge and water level variations were considered, besides several methods of measuring the tides (currents, water levels and discharges recorded at different stations and in different periods. The main point argued is that fluvial discharge is the key-factor in tidal distortion and tidal bore formation in the system investigated, whereas the low relief of the area would be the main factor contributing to landward tidal incursion. The results show an impressive upward tidal incursion of more than 200 km, including substantial distortion -increasing upstream -of the tidal wave, of which the ebb phase lasts up to 5 hours longer than the flood, including higher flood current velocities as far as 161 km upstream. Generally, only hyposynchronous tidal response was observed. Seasonally, the fluvial discharge varies about 10 times in the Guamá and 4 times in the Capim River. The increase of the fluvial discharge results in an increasing distortion of the tide, besides a weak increase of the attenuation. During high fluvial discharge periods in conjunction with equinoctial tides (e.g. March-April, a tidal bore occurs in the system, also increased by the generally low relief. Therefore, the conclusions include: low relief and the distortion related to high fluvial discharges are the main factors controlling tidal propagation along the system and tidal bore formation. Furthermore, the system could be classified as a tidal river, in which massive regional fresh water input results in virtually non-existent salinity throughout the Guamá-Capim system.O presente estudo teve como objetivo investigar a propagação da maré no sistema fluvial Guamá-Capim, na região amazônica, considerando aspectos hidrológicos e geomorfológicos. Os métodos empregados

  1. Diel and seasonal changes of Biogenic Volatile Organic Compounds within and above an Amazonian rainforest site

    Directory of Open Access Journals (Sweden)

    A. M. Yañez-Serrano

    2014-11-01

    Full Text Available The Amazonian rainforest is a large tropical ecosystem, and is one of the last pristine continental terrains. This ecosystem is ideally located for the study of diel and seasonal behaviour of Biogenic Volatile Organic Compounds (BVOC in the absence of local human interference. In this study, we report the first atmospheric BVOC measurements at the Amazonian Tall Tower Observatory (ATTO site, located in Central Amazonia. A quadrupole Proton Transfer Reaction Mass Spectrometer (PTR-MS with 7 ambient air inlets, positioned from near the ground to about 80 m (0.05, 0.5, 4, 24, 38, 53 and 79 m above the forest floor, was deployed for BVOC monitoring. We report diel and seasonal (February/March 2013 and September 2013 ambient mixing ratios for isoprene, monoterpenes, methyl vinyl ketone (MVK + methacrolein (MACR, acetaldehyde, acetone, methyl ethyl ketone (MEK, methanol and acetonitrile. Clear diel and seasonal patterns were observed for all compounds during the study. In general, lower mixing ratios were observed during night, while maximum mixing ratios were observed with the peak in solar irradiation at 12:00 LT during the wet season (February/March 2013, and with the peak in temperature at 16:00 LT during the dry season (September 2013. Isoprene mixing ratios were highest within the canopy with a median of 7.6 ppb and interquartile range (IQR of 6.1 ppb (dry season at 24 m, from 12:00–15:00. Monoterpene mixing ratios were higher than previously reported for any Amazonian rainforest ecosystem (median 1 ppb, IQR 0.38 ppb during the dry season at 24 m from 15:00–18:00. Oxygenated Volatile Organic Compound (OVOC patterns indicated a transition from dominating forest emissions during the wet season to a blend of biogenic emission, photochemical production, and advection during the dry season. This was inferred from the high mixing ratios found within the canopy, and those obtained above the canopy for the wet and dry season, respectively. Our

  2. Changes in Amazonian forest biomass, dynamics, and composition, 1980-2002

    Science.gov (United States)

    Phillips, Oliver L.; Higuchi, Niro; Vieira, Simone; Baker, Timothy R.; Chao, Kuo-Jung; Lewis, Simon L.

    Long-term, on-the-ground monitoring of forest plots distributed across Amazonia provides a powerful means to quantify stocks and fluxes of biomass and biodiversity. Here we examine the evidence for concerted changes in the structure, dynamics, and functional composition of old-growth Amazonian forests over recent decades. Mature forests have, as a whole, gained biomass and undergone accelerated growth and dynamics, but questions remain as to the long-term persistence of these changes. Because forest growth on average exceeds mortality, intact Amazonian forests have been functioning as a carbon sink. We estimate a net biomass increase in trees ≥10 cm diameter of 0.62 ± 0.23 t C ha-1 a-1 through the late twentieth century. If representative of the wider forest landscape, this translates into a sink in South American old-growth forest of at least 0.49 ± 0.18 Pg C a-1. If other biomass and necromass components also increased proportionally, the estimated South American old-growth forest sink is 0.79 ± 0.29 Pg C a-1, before allowing for possible gains in soil carbon. If tropical forests elsewhere are behaving similarly, the old-growth biomass forest sink would be 1.60 ± 0.58 Pg C a-1. This bottom-up estimate of the carbon balance of tropical forests is preliminary, pending syntheses of detailed biometric studies across the other tropical continents. There is also some evidence for recent changes in the functional composition (biodiversity) of Amazonian forest, but the evidence is less comprehensive than that for changes in structure and dynamics. The most likely driver(s) of changes are recent increases in the supply of resources such as atmospheric carbon dioxide, which would increase net primary productivity, increasing tree growth and recruitment, and, in turn, mortality. In the future the growth response of remaining undisturbed Amazonian forests is likely to saturate, and there is a risk of these ecosystems transitioning from sink to source driven by higher

  3. Diel and seasonal changes of Biogenic Volatile Organic Compounds within and above an Amazonian rainforest site

    Science.gov (United States)

    Yañez-Serrano, A. M.; Nölscher, A. C.; Williams, J.; Wolff, S.; Alves, E.; Martins, G. A.; Bourtsoukidis, E.; Brito, J.; Jardine, K.; Artaxo, P.; Kesselmeier, J.

    2014-11-01

    The Amazonian rainforest is a large tropical ecosystem, and is one of the last pristine continental terrains. This ecosystem is ideally located for the study of diel and seasonal behaviour of Biogenic Volatile Organic Compounds (BVOC) in the absence of local human interference. In this study, we report the first atmospheric BVOC measurements at the Amazonian Tall Tower Observatory (ATTO) site, located in Central Amazonia. A quadrupole Proton Transfer Reaction Mass Spectrometer (PTR-MS) with 7 ambient air inlets, positioned from near the ground to about 80 m (0.05, 0.5, 4, 24, 38, 53 and 79 m above the forest floor), was deployed for BVOC monitoring. We report diel and seasonal (February/March 2013 and September 2013) ambient mixing ratios for isoprene, monoterpenes, methyl vinyl ketone (MVK) + methacrolein (MACR), acetaldehyde, acetone, methyl ethyl ketone (MEK), methanol and acetonitrile. Clear diel and seasonal patterns were observed for all compounds during the study. In general, lower mixing ratios were observed during night, while maximum mixing ratios were observed with the peak in solar irradiation at 12:00 LT during the wet season (February/March 2013), and with the peak in temperature at 16:00 LT during the dry season (September 2013). Isoprene mixing ratios were highest within the canopy with a median of 7.6 ppb and interquartile range (IQR) of 6.1 ppb (dry season at 24 m, from 12:00-15:00). Monoterpene mixing ratios were higher than previously reported for any Amazonian rainforest ecosystem (median 1 ppb, IQR 0.38 ppb during the dry season at 24 m from 15:00-18:00). Oxygenated Volatile Organic Compound (OVOC) patterns indicated a transition from dominating forest emissions during the wet season to a blend of biogenic emission, photochemical production, and advection during the dry season. This was inferred from the high mixing ratios found within the canopy, and those obtained above the canopy for the wet and dry season, respectively. Our observations

  4. Fast demographic traits promote high diversification rates of Amazonian trees

    OpenAIRE

    Baker, Timothy R.; Pennington, R. Toby; Magallon, Susana; Gloor, Emanuel; Laurance, William F.; Alexiades, Miguel; Alvarez, Esteban; Araujo, Alejandro; Arets, Eric J. M. M.; Aymard, Gerardo; de Oliveira, Atila Alves; Amaral, Iêda; Arroyo, Luzmila; Bonal, Damien; Roel J.W. Brienen

    2014-01-01

    The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits - short turnover times - are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rat...

  5. Energetic planning in isolated Amazonian communities using geographical information system; Planejamento energetico em regioes isoladas da Amazonia utilizando sistemas de informacoes geograficas

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Arthur [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Programa de Pos-Graduacao de Engenharia Eletrica; Rocha, Brigida R.P.; Monteiro, Jose H.A.; Gaspar, Gabriella C.M. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Dept. de Engenharia Eletrica e de Computacao; Aarao Junior, Raimundo N.N. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Dept. de Engenharia Mecanica

    2004-07-01

    This paper proposes a system of electric planning in isolated Amazonian communities. For those communities, we propose the use of decentralized systems of electric energy with biomass as fuel. We also propose a computer system of electric planning with geographical information systems for its facilities of integrating geographical information, so useful in an Amazonian context. (author)

  6. Patterns of Vertebrate Diversity and Protection in Brazil

    OpenAIRE

    Jenkins, Clinton N.; Alves, Maria Alice S.; Uezu, Alexandre; Mariana M. Vale

    2015-01-01

    Most conservation decisions take place at national or finer spatial scales. Providing useful information at such decision-making scales is essential for guiding the practice of conservation. Brazil is one of the world’s megadiverse countries, and consequently decisions about conservation in the country have a disproportionate impact on the survival of global biodiversity. For three groups of terrestrial vertebrates (birds, mammals, and amphibians), we examined geographic patterns of diversity...

  7. Towards gene banking amphibian maternal germ lines: short-term incubation, cryoprotectant tolerance and cryopreservation of embryonic cells of the frog, Limnodynastes peronii.

    Directory of Open Access Journals (Sweden)

    Bianca Lawson

    Full Text Available Gene banking is arguably the best method available to prevent the loss of genetic diversity caused by declines in wild populations, when the causes of decline cannot be halted or reversed. For one of the most impacted vertebrate groups, the amphibians, gene banking technologies have advanced considerably, and gametes from the male line can be banked successfully for many species. However, cryopreserving the female germ line remains challenging, with attempts at cryopreserving oocytes unsuccessful due to their large size and yolk content. One possible solution is to target cryopreservation of early embryos that contain the maternal germ line, but consist of smaller cells. Here, we investigate the short term incubation, cryoprotectant tolerance, and cryopreservation of dissociated early embryonic cells from gastrulae and neurulae of the Striped Marsh Frog, Limnodynastes peronii. Embryos were dissociated and cells were incubated for up to 24 hours in various media. Viability of both gastrula and neurula cells remained high (means up to 40-60% over 24 hours of incubation in all media, although viability was maintained at a higher level in Ca(2+-free Simplified Amphibian Ringer; low speed centrifugation did not reduce cell viability. Tolerance of dissociated embryonic cells was tested for two cryoprotectants, glycerol and dimethyl sulphoxide; dissociated cells of both gastrulae and neurulae were highly tolerant to both-indeed, cell viability over 24 hours was higher in media containing low-to-medium concentrations than in equivalent cryoprotectant-free media. Viability over 24 hours was lower in concentrations of cryoprotectant higher than 10%. Live cells were recovered following cryopreservation of both gastrula and neurula cells, but only at low rates. Optimal cryodiluents were identified for gastrula and neurula cells. This is the first report of a slow cooling protocol for cryopreservation of amphibian embryonic cells, and sets future research

  8. 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...

  9. Phase-II conjugation ability for PAH metabolism in amphibians: characteristics and inter-species differences.

    Science.gov (United States)

    Ueda, Haruki; Ikenaka, Yoshinori; Nakayama, Shouta M M; Tanaka-Ueno, Tomoko; Ishizuka, Mayumi

    2011-10-01

    The present study examines amphibian metabolic activity - particularly conjugation - by analysis of pyrene (a four ring, polycyclic aromatic hydrocarbon) metabolites using high-performance liquid chromatography (HPLC) with fluorescence detector (FD), a mass spectrometry detector (MS) system and kinetic analysis of conjugation enzymes. Six amphibian species were exposed to pyrene (dissolved in water): African claw frog (Xenopus laevis); Tago's brown frog (Rana tagoi); Montane brown frog (Rana ornativentris); Wrinkled frog (Rana rugosa); Japanese newt (Cynops pyrrhogaster); and Clouded salamander (Hynobius nebulosus); plus one fish species, medaka (Oryzias latipes); and a fresh water snail (Clithon retropictus), and the resultant metabolites were collected. Identification of pyrene metabolites by HPLC and ion-trap MS system indicated that medaka mainly excreted pyrene-1-glucuronide (PYOG), while pyrene-1-sulfate (PYOS) was the main metabolite in all amphibian species. Pyrene metabolites in amphibians were different from those in invertebrate fresh water snails. Inter-species differences were also observed in pyrene metabolism among amphibians. Metabolite analysis showed that frogs relied more strongly on sulfate conjugation than did Japanese newts and clouded salamanders. Furthermore, urodelan amphibians, newts and salamanders, excreted glucose conjugates of pyrene that were not detected in the anuran amphibians. Kinetic analysis of conjugation by hepatic microsomes and cytosols indicated that differences in excreted metabolites reflected differences in enzymatic activities. Furthermore, pyrenediol (PYDOH) glucoside sulfate was detected in the Japanese newt sample. This novel metabolite has not been reported previously to this report, in which we have identified unique characteristics of amphibians in phase II pyrene metabolism.

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

    Science.gov (United States)

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

    2014-05-13

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

  11. 14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull type rotorcraft: Water-based and amphibian. 29.519 Section 29.519 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... § 29.519 Hull type rotorcraft: Water-based and amphibian. (a) General. For hull type rotorcraft,...

  12. RENO, NV, JANUARY 15, 2004: FACTORS IMPLICATED IN AMPHIBIAN POPULATION DECLINES IN THE UNITED STATES

    Science.gov (United States)

    Factors known or suspected to be adversely affecting native amphibian populations in the US were identified using information from 267 species accounts written in a standardized format by multiple authors in the forthcoming book, 'Status and Conservation of U.S. Amphibians'. Spec...

  13. Mitigating amphibian chytridiomycosis with bioaugmentation: characteristics of effective probiotics and strategies for their selection and use.

    Science.gov (United States)

    Bletz, Molly C; Loudon, Andrew H; Becker, Matthew H; Bell, Sara C; Woodhams, Douglas C; Minbiole, Kevin P C; Harris, Reid N

    2013-06-01

    Probiotic therapy through bioaugmentation is a feasible disease mitigation strategy based on growing evidence that microbes contribute to host defences of plants and animals. Amphibians are currently threatened by the rapid global spread of the pathogen, Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis. Bioaugmentation of locally occurring protective bacteria on amphibians has mitigated this disease effectively in laboratory trials and one recent field trial. Areas still naïve to Bd provide an opportunity for conservationists to proactively implement probiotic strategies to prevent further amphibian declines. In areas where Bd is endemic, bioaugmentation can facilitate repatriation of susceptible amphibians currently maintained in assurance colonies. Here, we synthesise the current research in amphibian microbial ecology and bioaugmentation to identify characteristics of effective probiotics in relation to their interactions with Bd, their host, other resident microbes and the environment. To target at-risk species and amphibian communities, we develop sampling strategies and filtering protocols that result in probiotics that inhibit Bd under ecologically relevant conditions and persist on susceptible amphibians. This filtering tool can be used proactively to guide amphibian disease mitigation and can be extended to other taxa threatened by emerging infectious diseases.

  14. Ultraviolet radiation and Vitamin D3 in amphibian health, behaviour, diet and conservation.

    Science.gov (United States)

    Antwis, R E; Browne, R K

    2009-10-01

    Amphibians are currently suffering a period of mass extinction with approximately 20% of species under severe threat and more than 120 species already extinct. In light of this crisis there is an urgency to establish viable ex situ populations and also find the causes of in situ declines. The role of ultraviolet radiation and Vitamin D(3) in amphibian health directly influences both ex situ and in situ populations. Vitamin D(3) can be photosynthesised endogenously via UV-B radiation (UV-B), or acquired through the diet, and then metabolised to calcitriol the biologically active hormonal form. Although, there is a lack of literature concerning Vitamin D(3) requirements and calcitriol synthesis in amphibians, amphibians are likely to have similar Vitamin D(3) requirements and metabolic processes as other vertebrates due to the phylogenetically conservative nature of calcitriol biosynthesis. Deficiencies in calcitriol in amphibians result in nutritional metabolic bone disease (NMBD) and could compromise reproduction and immunity. However, excess biologically active UV radiation has also proven detrimental across all three amphibian life stages and therefore could impact both in situ and ex situ populations. Here we review the role and necessity of UV-B and calcitriol in amphibians and the potential for negative impacts due to excessive exposure to UV radiation. We also identify priorities for research that could provide critical information for maintaining healthy in ex situ and in situ populations of amphibians.

  15. 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.

  16. Detecting the effects of environmentally relevant concentrations of thyroid hormone disrupting compounds on amphibian development

    NARCIS (Netherlands)

    Gutleb, A.C.

    2006-01-01

    Persistent organic pollutants such as PCBs have been hypothesized to contribute to the observed global decline of amphibian populations. Thyroid hormone (TH) disruption is one of the possible mechanisms for effects of xenobiotics on amphibian development. In addition to the important functions share

  17. 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...

  18. A meta-analysis of the effects of pesticides and fertilizers on survival and growth of amphibians.

    Science.gov (United States)

    Baker, Nick J; Bancroft, Betsy A; Garcia, Tiffany S

    2013-04-01

    The input of agrochemicals has contributed to alteration of community composition in managed and associated natural systems, including amphibian biodiversity. Pesticides and fertilizers negatively affect many amphibian species and can cause mortality and sublethal effects, such as reduced growth and increased susceptibility to disease. However, the effect of pesticides and fertilizers varies among amphibian species. We used meta-analytic techniques to quantify the lethal and sublethal effects of pesticides and fertilizers on amphibians in an effort to review the published work to date and produce generalized conclusions. We found that pesticides and fertilizers had a negative effect on survival of -0.9027 and growth of -0.0737 across all reported amphibian species. We also observed differences between chemical classes in their impact on amphibians: inorganic fertilizers, organophosphates, chloropyridinyl, phosphonoglycines, carbamates, and triazines negatively affected amphibian survival, while organophosphates and phosphonoglycines negatively affected amphibian growth. Our results suggest that pesticides and fertilizers are an important stressor for amphibians in agriculturally dominated systems. Furthermore, certain chemical classes are more likely to harm amphibians. Best management practices in agroecosystems should incorporate amphibian species-specific response to agrochemicals as well as life stage dependent susceptibility to best conserve amphibian biodiversity in these landscapes.

  19. A review of cryptic species in amphibians%隐种及其在两栖动物中的研究进展

    Institute of Scientific and Technical Information of China (English)

    黄华; 郑荣泉; 张加勇; 陈雯; 于晓云; 陈平

    2012-01-01

    近年来,由于分子生物学的迅猛发展,物种内隐藏的生物多样性越来越多地被发现,由此引发的隐种问题也备受关注.隐种的存在对现有的生物多样性评估提出了挑战.在实践上,隐种的界定对于自然资源的保护和管理具有重要意义.两栖动物由于迁移能力较弱,通常具有较强的遗传分化,因而可能包含较丰富的隐种多样性.简述了隐种的概念和形成机制,归纳了国内外两栖类动物中隐种的研究进展,并着重介绍了界定两栖动物隐种的研究方法,最后,对今后两栖动物隐种的研究作了简要展望.我国两栖动物资源丰富,并具有独特的地形和气候特点,对这些物种遗传多样性和系统地理学的研究亟待开展.%With the rapid development of molecular biology in recent years, more and more hidden biodiversity within the species was discovered, and many people begin to pay attention to the cryptic species problem. There are many challenges on biodiversity estimation because of the prevalence of cryptic species. In practice, the identification and description of cryptic species complexes have important implications for conservation and natural resource protection and management. Due to the weak of migration and strong philopatric. amphibians usually have a strong genetic differentiation and might be storehouses of tremendous cryptic diversity. The paper has briefly described the concept and formative mechanism of cryptic species, summarized the research status and introduced the methods of definition of cryptic species importantly in amphibians at home and abroad. In addition, we also discussed the prospects of researches on cryptic species in amphibians. There are rich amphibian resources, unique topography and climate character in China, so that it is urgent to research on both genetic diversity and phylogeography of these amphibian species.

  20. 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.