Algo triste - y escalofriante para nosotros - ha sucedido con los anfibios del planeta, una de las ramas de los vertebrados más antiguos en la historia de la vida: se están extinguiendo.
Debido a que tienen pieles porosas por donde respiran, sus cuerpos son muy vulnerables a todo tipo de cambios, y al ser seres tan delicados si esos cambios son fatales, ellos los detectan primero. Y eso ha sucedido. Después de haber sobrevivido a meteoros gigantes que terminaron con los dinosaurios, y a cambios repentinos de clima que terminaron con miles de especies no están pudiendo sobrevivir a algo que hemos producido los humanos: la contaminación ambiental.
Un estudio hecho público a nivel mundial y dado a conocer ayer revela que casi un tercio de todos los anfibios está a punto de desaparecer, y eso ha hecho sonar la alarma de la mina sobre el estado de la vida en la Tierra. Durante tres años, 500 científicos en 60 países hicierone este estudio y su conclusión es aterradora.
"This is a problem way outside what we know," said Simon Stuart of the World Conservation Union and leader of the study published in the online version of the journal Science.
Dr Stuart said: "This level of decline is ... extraordinary and serious because amphibians represent a very important part of the overall diversity of life. Since most amphibians feel the effects of pollution before many other forms of life, their rapid decline tells us that one of earth's most critical life support systems is breaking down."
The figures in the survey are almost certainly underestimates because more than 22 per cent of the known amphibian species are too poorly understood for the researchers to reach a reliable conclusion about what is happening to them.
Populations of almost half of the known amphibian species are in decline. While 32 per cent of amphibians are threatened with extinction, only 12 per cent of birds and 23 per cent of mammals are in the same position. The latest study estimates that up to 122 species have gone extinct since 1980.
Dr Stuart said that all animal groups undergo a natural "background" rate of extinction but, in the case of amphibians, the actual loss of species is equivalent to the total number of background extinctions for many tens of thousands of years being squeezed into a single century.
"The bottom line is that there's almost no evidence of recovery and no known techniques for saving mysteriously declining species in the wild. It leaves conservation biologists in a quandary," Dr Stuart said."
México, informa el estudio, tiene mucha de su población de anfibios en peligro, y es al agua contaminada la principal causante...
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