The Yosemite toad and the Sierra Nevada yellow-legged frogs share some critical mountain habitat and now a dubious distinction: both are being proposed for federal Endangered Species Act protection. Yellow-legged frogs were once common thfroughout the Sierra Nevada but have declined in numbers in recent years due to habitat destruction, predation by non-native trout in mountain waterways, drifting pesticides and climate change. Yosemite toads are threatened primarily by livestock grazing, climate change and pesticides. The proposal by the U.S. Fish and Wildlife Service includes designating 2 million acres of critical habitat.