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Angulo Ariadne - One of the best experts on this subject based on the ideXlab platform.
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ANFIBIOS Y PARADOJAS: PERSPECTIVAS SOBRE LA DIVERSIDAD Y LAS POBLACIONES DE ANFIBIOS
Departamento Académico de Biología, 2016Co-Authors: Angulo AriadneAbstract:La pérdida de diversidad biológica es un hecho finalmente reconocido y establecido, tanto a nivel de la comunidad científica como del público en general (Santini & Angulo, 2001). Esta pérdida se viene dando a todo nivel taxonómico, y mayormente por causales tales como cambios climáticos, disminución y fragmentación de hábitats y contaminación del medio ambiente. Sin embargo, hace poco más de una década se comenzó a sospechar que había algo más que no andaba bien con las poblaciones de anfibios en partes tan diversas del mundo como Australia, Norte América, Europa, Sur y Centro América. Coincidentemente, alrededor de la misma época, se iría a realizar el Primer Congreso Mundial de Herpetología en Canterbury, Inglaterra, en 1989 (Halliday & Heyer, 1997), e investigadores de todos los rincones del planeta comenzaron a intercambiar experiencias con otros colegas acerca de sus grupos de estudio. Si bien estas narraciones eran de naturaleza anecdótica y de la experiencia personal de cada investigador (Young, 1990; Pechmann et al., 1991) más que de un estudio propiamente dicho, había un consenso bastante generalizado: poblaciones de anfibios en todo el mundo parecían estar reduciéndose. Anfibios que anteriormente habían sido abundantes en ciertas áreas ahora se encontraban con gran esfuerzo y dificultad, como en el caso de los sapos boreales de las montañas de Colorado y Wyoming, en EEUU (Barinaga, 1990) o el sapo Americano enano Bufo americanus charlesmithi, anteriormente muy abundante en el condado de Cleveland, Oklahoma (Pechmann & Wilbur, 1994). En ocasiones, habían especies que parecían haber desaparecido del todo de sus hábitats, como en el caso de las ranas Rheobatrachus silus y Rheobatrachus vitelinus de los bosques de Queensland, Australia, que llevan a sus crías en el estómago; o el caso de la rana y el sapo dorados (Atelopus varius y Bufo periglenes, respectivamente) de Monteverde, Costa Rica (Griffiths & Beebee, 1992; Pounds y Crump, 1994). Estos son apenas contados ejemplos de una triste y alarmante lista de anfibios. Uno de los problemas que se hizo evidente al tratar el tema es que no se disponía de información de censos a largo plazo (Blaustein, 1994), o de una base de datos de la dinámica de las poblaciones a largo plazo, y por ello no se sabía si lo que aparentaba ser una disminución en una población era en realidad una fluctuación natural de la misma, cosa que suele suceder en poblaciones en general. Otra dificultad la constituía el no poder precisar si existía algún factor en particular que estuviera provocando estas reducciones, o si era un conjunto de factores los que estaban suscitando este fenómeno. Posteriormente a este congreso, el tema se volvió de gran preocupación tanto para la comunidad científica como para las personas y entidades ligadas a la conservación de biodiversidad: ¿Se estarán extinguiendo nuestros anfibios? ¿Serán estos animales indicadores ambientales de su entorno y por ello serían los primeros en ser afectados? ¿Porqué están desapareciendo los anfibios del planeta? Fue el inicio de un esfuerzo conjunto a nivel mundial para investigar este fenómeno
Thomas C Burton - One of the best experts on this subject based on the ideXlab platform.
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variation in the foot muscles of frogs of the family myobatrachidae
Australian Journal of Zoology, 2001Co-Authors: Thomas C BurtonAbstract:The hind-foot musculature of representatives of all myobatrachid frog genera was examined with a view to finding phylogenetic characters and characters correlated with the burrowing habit. Despite much intraspecific variation, evidence was found to support the monophyly of Mixophyes(possession of a fibrous section in the tendon of insertion of the m. lumbricalis longus digiti V, tendinous insertion of the m abductors brevis dorsalis digiti V), Rheobatrachus (threefold insertion of the m. extensor longus digiti IV), Neobatrachus +Heleioporus (possession of the m. lumbricalis longus digiti II), Pseudophryne + Metacrinia(loss or reduction of medial slip of the m. lumbricalis brevis digiti V), Adelotus + Heleioporus +Limnodynastes (minus L. ornatus-group) +Neobatrachus+Notaden (possession of a transversus-like muscle between the first metatarsus and the prehallux), and Rheobatrachus + Myobatrachinae (reduction of the m. plantaris brevis plantaris digiti V). Differences were found in the musculature associated with the metatarsal tubercles between (a) rear-foot-burrowing frogs of the genera Notaden, Neobatrachus,Heleioporus and Limnodynastes (minus L. ornatusandL. spenceri); (b)L. ornatus and L. spenceri; and (c)Uperoleia. The differences indicate separate evolution of burrowing in these taxa. A new muscle, the m. adductor praehallucis, is described. From its structure and distribution among species, this muscle appears to be associated with the burrowing habit.
Rowley, Jodi J.l. - One of the best experts on this subject based on the ideXlab platform.
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Amphibian declines in Australia
Lynx Edicions, 2008Co-Authors: Alford, Ross A., Rowley, Jodi J.l.Abstract:[Extract] Concern about the status of Australian frogs first arose in the 1980s with the disappearance of the famous gastric-brooding frogs: Rheobatrachus silus {described in 1973, and last seen in the wild in 1985}, and R. vitelinus {described in 1984, and last seen in the wild in 1985} (Ingram and Mcdonald 1993; and see Essay 6.1). Intensive searches for both of these species were conducted in teh late 1980s, with no individuals located then, or since, and they are both now listed as Extinct on the IUCN Red List. This represents the loss of an entire family, as well as a unique reproductive strategy
Alford, Ross A. - One of the best experts on this subject based on the ideXlab platform.
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Amphibian declines in Australia
Lynx Edicions, 2008Co-Authors: Alford, Ross A., Rowley, Jodi J.l.Abstract:[Extract] Concern about the status of Australian frogs first arose in the 1980s with the disappearance of the famous gastric-brooding frogs: Rheobatrachus silus {described in 1973, and last seen in the wild in 1985}, and R. vitelinus {described in 1984, and last seen in the wild in 1985} (Ingram and Mcdonald 1993; and see Essay 6.1). Intensive searches for both of these species were conducted in teh late 1980s, with no individuals located then, or since, and they are both now listed as Extinct on the IUCN Red List. This represents the loss of an entire family, as well as a unique reproductive strategy
Hoskin C.j. - One of the best experts on this subject based on the ideXlab platform.
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An update on the status of wet forest stream-dwelling frogs of the Eungella region
The Royal Society of Queensland, 2020Co-Authors: Meyer E.a., Hines H.b., Clarke J.m., Hoskin C.j.Abstract:Eungella’s wet forests are home to a number of stream-breeding frogs including three species endemic to the Eungella region: the Eungella dayfrog (Taudactylus eungellensis), Eungella tinkerfrog (T. liemi), and northern gastric brooding frog (Rheobatrachus vitellinus). During the mid-1980s, T. eungellensis and R. vitellinus suffered dramatic population declines attributable to amphibian chytridiomycosis, a disease caused by the amphibian chytrid fungus (Batrachochytrium dendrobatidis or Bd). While surveys in the late 1980s failed to locate T. eungellensis or R. vitellinus, populations of the former were located on a handful of streams surveyed by researchers in the mid-to-late 1990s. Between January 2000 and November 2015, additional surveys targeting these and other wet forest frog species were conducted at 114 sites within Eungella National Park and adjoining areas of State Forest. During these surveys, we located T. eungellensis at many more sites than surveys in the 1990s. Abundances of T. eungellensis at these sites were typically low, however, and well below abundance levels prior to declines in the mid-1980s. As with surveys in the 1990s, T. eungellensis was scarce at high-elevation sites above 600 metres altitude. Numbers of this species do not appear to have increased significantly since the mid-1990s, suggesting recovery of T. eungellensis populations is occurring slowly, at best. In contrast with T. eungellensis, T. liemi was frequently recorded at high-elevation sites, albeit at low densities. As with previous surveys, surveys during 2000–2015 were unsuccessful in locating R. vitellinus. Further frog surveys and monitoring (including disease surveillance) are needed to better assess the status of stream frogs at Eungella, and to understand the influence of Bd on the abundance and distribution of threatened stream-dwelling frogs at Eungella