February 8, 2000 – The Center filed a petition to list the Sierra Nevada frog population as endangered under the Endangered Species Act. One of the largest yellow-legged frog populations containing more than 2,000 adult frogs in 1996 had almost completely disappeared by 1999, when only two frogs were found. The U.S. Fish and Wildlife Service published an initial finding that listing the species may be warranted and initiated a status review to determine whether listing was appropriate.
May 31, 2001 – The Service failed to make a final listing determination, and the Center filed a lawsuit to compel the agency to respond to the petition. The Northern District Court ordered the Service to make a listing determination by 2003.
January 16, 2003 – The Service published a finding that the overall magnitude of threats to the frog is high and that the overall immediacy of these threats is imminent. Despite concluding that listing the frog as an endangered species is warranted, the Service placed the species on the candidate list, claiming that Endangered Species Act listing is “precluded” by higher-priority listing actions. The Center filed a second lawsuit challenging the delay of Endangered Species Act protection.
2004 – The District Court ruled in favor of the Service and dismissed the Center's lawsuit. The Center filed an appeal with the U.S. Ninth Circuit Court of Appeals.
2005 – The Center filed a lawsuit challenging the Service's delay of Endangered Species Act protection for 225 candidate species, including the mountain yellow-legged frog.
2006 – The Court of Appeals ruled in favor of the Center and ordered the Service to comply with its legal obligation under the Endangered Species Act and again consider whether Sierra Nevada mountain yellow-legged frogs deserve listing as a protected species.
June 25, 2007 – The Service again determined that the listing of the Sierra Nevada mountain yellow-legged frog was warranted but “precluded.”
June 22, 2010 – In response to our petition, the California Fish and Game Commission recommended that the state formally evaluate the status of the mountain yellow-legged frog and consider listing the species as endangered or threatened under the California Endangered Species Act.
September 15, 2010 – The California Fish and Game Commission designated all populations of the mountain yellow-legged frog as a candidate species, the first step toward a state listing as endangered or threatened. Unfortunately, the Commission also adopted emergency rules allowing “incidental take” — killing or capture of frogs — during activities such as the state's environmentally damaging fish-stocking program.
July 12, 2011 – The Center struck a historic legal settlement with the U.S. Fish and Wildlife Service, requiring the agency to make initial or final Endangered Species Act decisions on 757 imperiled plants and animals — including the mountian yellow-legged frog — by 2018.
February 2, 2012 – The California Fish and Game Commission voted unanimously to designate Sierra Nevada mountain yellow-legged frogs as threatened and Southern California mountain yellow-legged frogs as endangered under the state's Endangered Species Act.
April 24, 2013 – In accordance with our historic 2011 agreement with the U.S. Fish and Wildlife Service, the agency proposed federal Endangered Species Act protection for Sierra Nevada yellow-legged frogs and Yosemite toads, along with more than 2 million acres of proposed critical habitat across the Sierra Nevada mountains. The Service also proposed protection for a population of mountain yellow-legged frogs that lives in the southern Sierra Nevada. Proposed critical habitat included 1,105,400 acres for the Sierra Nevada yellow-legged frog and 221,498 acres for the northern “distinct population segment” of the mountain yellow-legged frog.
June 8, 2016 – The Center filed a notice of intent to sue the U.S. Forest Service for authorizing livestock grazing on the Humboldt-Toiyabe National Forest without considering the potential impacts to federally protected Sierra Nevada yellow-legged frogs and Yosemite toads.
August 25, 2016 – The Fish and Wildlife Service announced designation of 1,812,164 acres of protected critical habitat throughout the Sierra Nevada for several endangered amphibians: the Sierra Nevada yellow-legged frog, Yosemite toad and northern population of the mountain yellow-legged frog. The Sierra Nevada yellow-legged frog earned 1,082,147 acres and the northern population of the mountain yellow-legged frog was given 221,498 acres.