They say studies have shown populations of the Sierra Nevada yellow-legged frog have declined by almost 70 percent while the northern Distinct Population Segment (DPS) of mountain yellow-legged frog declined by over 80 percent. The Yosemite toad faces similar challenges with range-wide declines estimated at almost 50 percent.
The amphibians live primarily on publicly managed lands at high elevations. They can be found in streams, lakes, ponds, and meadow habitats in 17 counties in California -- including Fresno, Madera, Mariposa, and Tulare counties.
U.S. Fish and Wildlife Service says habitat degradation, disease, predation and the effects of climate change are contributing factors to the documented decline of these species and continue to pose a threat to their recovery.
"This final rule is the result of exhaustive research, public comment, and scientific peer review," said Jennifer Norris, Field Supervisor for the Service's Sacramento Field Office. "While other moderate and minor level threats including historic logging, mining, grazing pressures and recreational use were evaluated, they were not considered significant factors in our determination."
The Fish and Wildlife Service said the final rule is expected to be published on Tuesday and will become effective on June 30th. A final decision on the critical habitat proposal is expected to be made early next year.
The Sierra Nevada yellow-legged frog and the northern DPS of the mountain yellow-legged frog are similar in appearance and behavior. They range from 1.5 to 3.25 inches in length and are a mix of brown and yellow, but can also be grey, red, or green-brown. They may have irregular lichen- or moss-like patchiness. Their belly and undersurfaces of the hind limbs are yellow or orange. They produce a distinctive mink or garlic-like order when disturbed.
The Yosemite toad is moderately sized, usually 1.2–2.8 inches in length, with rounded to slightly oval glands, one on each side of the head, which produce toxins to deter some predators. The iris of the eye is dark brown with gold reflective cells.