There's been a lot of finger pointing in California environmental circles regarding declines in the populations of yellow-legged and red-legged frogs and Yosemite toads in the High Sierra. And most of the fingers have been pointing at pesticides that they claim are drifting from farmers, many of them miles from the mountains, as the cause for the frog die-off..
It now looks as if the fingers may have been pointed prematurely.
Scientists have identified one of the main frog-killing culprits, a fungus known as Batrachocytrium dendrobatidis. They say that the waterborne fungus kills frogs by damaging their skin.
There could be (and probably are) other contributing factors, scientists speculate, including an increase in the levels of solar ultraviolet radiation reaching the High Sierra. In fact, nobody is 100% certain exactly why the number of amphibians is decreasing so rapidly. It's premature to lay the blame on one factor, most scientists now recognize as they continue to study the problem. — Ron Hall