Examinando por Autor "Soto-Azat, Claudio"
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Ítem Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity(American Association for the Advancement of Science, 2019) Scheele, Ben C.; Pasmans, Frank; Skerratt, Lee F.; Berger, Lee; Martel, An; Beukema, Wouter; Acevedo, Aldemar A.; Burrowes, Patricia A.; Carvalho, Tamilie; Catenazzi, Alessandro; De La Riva, Ignacio; Fisher, Matthew C.; Flechas, Sandra V.; Foster, Claire N.; Frías-Álvarez, Patricia; Garner, Trenton W.J.; Gratwicke, Brian; Guayasamin, Juan M.; Hirschfeld, Mareike; Kolby, Jonathan E.; Kosch, Tiffany A.; Marca, Enrique La.; Lindenmayer, David B.; Lips, Karen R.; Longo, Ana V.; Maneyro, Raúl; McDonald, Cait A.; Mendelson, Joseph; Palacios-Rodriguez, Pablo; Parra-Olea, Gabriela; Richards-Zawacki, Corinne L.; Rödel, Mark-Oliver; Rovito, Sean M.; Soto-Azat, Claudio; Toledo, Luís Felipe; Voyles, Jamie; Weldon, Ché; Whitfield, Steven M.; Wilkinson, Mark; Zamudio, Kelly R.; Canessa, StefanoAnthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity.We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions.The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease.Ítem Assessing habitat quality when forest attributes have opposing effects on abundance and detectability: A case study on Darwin's frogs(Forest Ecology and Management, 2019-01-15) Valenzuela-Sánchez, Andrés; Schmidt, Benedikt R.; Pérez, Catalina; Altamirano, Tania; Toledo, Verónica; Pérez, Ítalo; Teillier, Sebastián; Cunninghami, Andrew A.; Soto-Azat, ClaudioForest management can be used to increase the local abundance of species of conservation concern. To achieve this goal, managers must be sure that the relationships between the targeted forest attributes and the focal species abundance are based on robust data and inference. This is a critical issue as the same forest attributes could have opposing effects on species abundance and the detectability of individuals, impairing our ability to detect useful habitat quality surrogates and to provide correct forest management recommendations. Using spatially stratified capture-recapture models (a.k.a. multinomial N-mixture models), we evaluated the effects of stand-level forest attributes on detection probability and local abundance for the endangered Southern Darwin's frog (Rhinoderma darwinii), a forest-specialist and fully terrestrial amphibian endemic to the South American temperate forest. Our results show that an increase of stand basal area and a decrease of daily microclimatic fluctuation (i.e. an increase in structural complexity) were positively associated with the local abundance of R. darwinii. These stand-level forest attributes also explained the among-population variation in detection probability, although the relationships were opposite to those for abundance. Consequently, an analysis of raw frog counts (i.e. not adjusted for imperfect detection) did not reveal all the factors associated with local abundance. Our results provide further support to previous claims that raw counts of individuals should not be used, generally, as a proxy of abundance in species inhabiting forest ecosystems and elsewhere. More importantly, the opposite effect of forest attributes on abundance and detectability observed in our study highlights the need to use methods that quantify species-habitat relationships in a robust way and which take habitat-specific imperfect detection into account.Ítem Conservación de anfibios de Chile: memorias del taller de conservación de anfibios para organismos públicos(Universidad Andrés Bello, 2012) Soto-Azat, Claudio; Valenzuela-Sánchez, AndrésLos anfibios han dado origen a toda la diversidad de vertebrados presentes en la tierra, incluyendo a nosotros, los seres humanos. Los anfibios mantienen los ecosistemas equilibrados y controlan de forma natural las plagas de insectos. Debido a la naturaleza permeable de su piel, son los primeros en desparecer cuando el agua está contaminada, lo que los hace excelentes indicadores de la salud del ecosistema. Desafortunadamente, los anfibios enfrentan una crisis de extinción y declinación de poblaciones, sin precedentes. Un tercio de los anfibios están amenazados de extinción. Producto del constante crecimiento humano, la pérdida de sus hábitats se ha incrementado a tasas insospechadas en los últimos años, y la globalización a facilitado la introducción de especies invasoras y los ha dejado expuestos a patógenos nuevos con efectos catastróficos para algunas poblaciones. Por otro lado, el calentamiento global es reconocido como una nueva amenaza con insospechados efectos sobre este grupo de animales altamente dependientes del agua. Chile presenta una batracofauna más bien pequeña cuando se compara con otros países de Sudamérica, sin embargo que se caracteriza por su alto grado de endemismo, con diversas formas y tamaños que han evolucionado de forma independiente y con especies adaptadas a vivir en ambientes bastante desiguales, desde el árido norte, las alturas de los Andes, pasando por la zona mediterránea, llegando a los bosques templados y fríos del sur de Chile. En los últimos años se ha producido un explosivo aumento en la investigación de anfibios de nuestro país, y así han surgido también nuevas problemáticas para su conservación. El continuo aumento de la invasión de la rana Africana, la reciente descripción del hongo Batrachochytrium dendrobatidis causante de la chytridiomicosis de los anfibios, la descripción de nuevas especies y la aplicación de nuevas técnicas en estudios genéticos, son solo algunos ejemplos de nuevos desafíos de la conservación de los anfibios en Chile. Como un ejemplo puntual, una situación alarmante en la batracofauna chilena se visualiza en el género Telmatobius que en su mayoría son especies riparianas que viven en arroyos cordilleranos de la región desértica y la de puna seca. El género en su totalidad esta en peligro de extinción, por la destrucción del ambiente ya sea por efecto de las mineras, sustracción de aguas y canalización de los pocos arroyos existentes en la zona. Se suma a esto que la taxonomia del género es incierta y no ha sido estudiada en su conjunto, conociéndose la mayoría de las especies solo en la localidad tipo. En este contexto, la organización del taller de Conservación de anfibios para organismos públicos, realizado en la Universidad Andrés Bello los días 7 y 8 de Julio de 2011, buscó ser una plataforma de información y discusión sobre estos temas con aquellas personas encargadas de su protección, gestión y conservación. Esperamos que este libro sea un aporte al conocimiento y protección de la biodiversidad.Ítem Cryptic disease-induced mortality may cause host extinction in an apparently stable host-parasite system(Proceedings of the Royal Society, 2017-09) Valenzuela-Sánchez, Andrés; Schmidt, Benedikt R.; Uribe-Rivera, David E.; Costas, Francisco; Cunningham, Andrew A.; Soto-Azat, ClaudioThe decline of wildlife populations due to emerging infectious disease often shows a common pattern: the parasite invades a naive host population, producing epidemic disease and a population decline, sometimes with extirpation. Some susceptible host populations can survive the epidemic phase and persist with endemic parasitic infection. Understanding host- parasite dynamics leading to persistence of the system is imperative to adequately inform conservation practice. Here we combine field data, statistical and mathematical modelling to explore the dynamics of the apparently stable Rhinoderma darwinii-Batrachochytrium dendrobatidis (Bd) system. Our results indicate that Bd-induced population extirpation may occur even in the absence of epidemics and where parasite prevalence is relatively low. These empirical findings are consistent with previous theoretical predictions showing that highly pathogenic parasites are able to regulate host populations even at extremely low prevalence, highlighting that disease threats should be investigated as a cause of population declines even in the absence of an overt increase in mortality. © 2017 The Author(s) Published by the Royal Society. All rights reserved.Ítem Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: Lessons from the first 15 years of amphibian chytridiomycosis research(John Wiley and Sons Ltd, 2015-09) James, Timothy Y.; Toledo, L. Felipe; Rödder, Dennis; da Silva Leit, Domingos; Belasen, Anat M.; Betancourt-Román, Clarisse M.; Jenkinson, Thomas S.; Soto-Azat, Claudio; Lambertini, Carolina; Longo, Ana V.; Ruggeri, Joice; Collins, James P.; Burrowes, Patricia A.; Lips, Karen R.; Zamudio, Kelly R.; Longcore, Joyce E.The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co-evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities. © 2015 John Wiley & Sons Ltd.Ítem High prevalence of chigger mite infection in a forest-specialist frog with evidence of parasite-related granulomatous myositis(Springer Verlag, 2018-05) Alvarado-Rybak, Mario; Valenzuela-Sánchez, Andrés; Cevidanes, Aitor; Peñafiel-Ricaurte, Alexandra; Uribe-Rivera, David E.; Flores, Edgardo; Cunningham, Andrew A.; Soto-Azat, ClaudioAmphibians are hosts for a wide variety of micro- and macro-parasites. Chigger mites from the Hannemania genus are known to infect a wide variety of amphibian species across the Americas. In Chile, three species (H. pattoni, H. gonzaleacunae and H. ortizi) have been described infecting native anurans; however, neither impacts nor the microscopic lesions associated with these parasites have been described. Here, we document 70% prevalence of chigger mite infection in Eupsophus roseus and absence of infection in Rhinoderma darwinii in the Nahuelbuta Range, Chile. Additionally, we describe the macroscopic and microscopic lesions produced by H. ortizi in one of these species, documenting previously undescribed lesions (granulomatous myositis) within the host’s musculature. These findings highlight that further research to better understand the impacts of chigger mite infection on amphibians is urgently required in Chile and elsewhere. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.Ítem Recent Asian origin of chytrid fungi causing global amphibian declines(American Association for the Advancement of Science, 2018-05) O’Hanlon, Simon J.; Rieux, Adrien; Farrer, Rhys A.; Rosa, Gonçalo M.; Waldman, Bruce; Bataille, Arnaud; Kosch, Tiffany A.; Murray, Kris A.; Brankovics, Balázs; Fumagalli, Matteo; Martin, Michael D.; Wales, Nathan; Alvarado-Rybak, Mario; Bates, Kieran A.; Berger, Lee; Böll, Susanne; Brookes, Lola; Clare, Frances; Courtois, Elodie A.; Cunningham, Andrew A.; Doherty-Bone, Thomas M.; Ghosh, Pria; Gower, David J.; Hintz, William E.; Höglund, Jacob; Jenkinson, Thomas S.; Lin, Chun-Fu; Laurila, Anssi; Loyau, Adeline; Martel, An; Meurling, Sara; Miaud, Claude; Minting, Pete; Pasmans, Frank; Schmeller, Dirk S.; Schmidt, Benedikt R.; Shelton, Jennifer M. G.; Skerratt, Lee F.; Smith, Freya; Soto-Azat, Claudio; Spagnoletti, Matteo; Tessa, Giulia; Toledo, Luís Felipe; Valenzuela-Sánchez, Andrés; Verster, Ruhan; Vörös, Judit; Webb, Rebecca J.; Wierzbicki, Claudia; Wombwell, Emma; Zamudio, Kelly R.; Aanensen, David M.; James, Timothy Y.; Thomas P. Gilbert M.; Weldon, Ché; ;Bosch, Jaime; Balloux, François; Garner, Trenton W. J.; Fisher, Matthew C.Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide. © 2017 The Authors.Ítem Response to Comment on “Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity”(American Association for the Advancement of Science, 2020-03) Scheele, Ben C.; Pasmans, Frank; Lee F, Skerratt; Lee, Berger; An, Marte; Wouter, Beukema; Acevedo, Aldemar; Burrowes, Patricia; Carvalho, Tamilie; Catenazzi, Alessandro; De la Riva, Ignacio; Fisher, Matthew C; Flechas, Sandra V; Foster, Claire N; Frías-Álvarez, Patricia; Trenton W. J, . Garner; Gratwicke, Brian; Guayasamin, Juan M; Hirschfeld, Mareike; Kolby, Jonathan; . Kosch, Tiffany; La Marca, Enrique; Lindenmayer, David B.; Lips, Karen R; Longo, Ana V; Maneyro, Raúl; McDonald, Cait A; Mendelson III, Joseph; Palacios-Rodriguez, Pablo; Parra-Olea, Gabriela; Corinne L, Richards-Zawack; Rödel, Mark-Oliver; Rovito, Sean M.; Soto-Azat, Claudio; Toledo, Luís Felipe; Voyles, Jaime; Weldon, Ché; Whitfield, Steven M.; Wilkinson, Mark W; . Zamudio, Kelly R; Canessa, StefanoLambert et al. question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species.