For the past 20 years, one scientist after another has released studies showing major declines of frogs, toads, and salamanders across America. Habitat destruction, conflicts with introduced non-native amphibians, pesticide contamination, and a warming climate have all caused major damage to native amphibian species.
In the Sierra Nevada, the California red-legged frog has completely disappeared from most of the region. The foothill yellow-legged frog is also gone from most of its historic range, as is the Sierra Nevada yellow-legged frog of the higher mountains. The Yosemite toad has declined drastically from many high country lakes and meadows, due in part to livestock grazing, but also due to other factors. Even the still-common Pacific tree frog (chorus frog) is far less abundant than in past decades.
Ensantina Salamander |
Sierra Nevada Yellow-Legged Frog |
On top of all of the above grim information, local region amphibians are suffering from a devastating threat. The chytrid fungus is wiping out amphibians all around the world. This deadly fungus has spread pervasively across continents and even into remote regions of the planet... literally wiping out many frog and salamander species. Amphibian species are especially vulnerable when habitat destruction, pesticide pollution, and other human-caused impacts are already stressing their populations.
In the local region, as recently as the 1970's, CSERC's director watched after warm spring rains as literally hundreds of frogs and toads could be seen crossing roads in night-time travels. Drought conditions of the late 1970's and even more prolonged drought periods in the 1980's set back many amphibian populations to far lower numbers than normal. Drier than normal weather patterns over the past decade, combined with so many widespread human activities, have further decimated amphibian numbers in the region.
The link below features a National Geographic article on the vanishing amphibian situation. It is definitely worth viewing.
http://ngm.nationalgeographic.com/2009/04/amphibian/holland-text
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