Frogs are now extinct from this lake in Kings Canyon National ParkMountain yellow-legged frogs have disappeared from thousands of sites despite the fact that the habitat at these sites is essentially unaltered from its natural condition. Therefore, although habitat alteration is a primary threat to amphibians worldwide, it is likely to have played a minor role in the decline of the mountain yellow-legged frog. Scientists interested in understanding the causes underlying the decline of the mountain yellow-legged frog have therefore focused their attention on four other factors: introduction of nonnative fishes, disease, contaminants, and elevated levels of ultraviolet (UV) radiation. Research conducted during the past 15 years has greatly increased our understanding of the relative importance of these potential stressors.

Read on….