Yosemite Toad (Anaxyrus canorus)
April 25, 2013 News: US Fish and Wildlife Service proposes "threatened with extinction" status for Yosemite Toad
Read the press release and associated documents.
The Yosemite Toad is declining in both population and range throughout the Sierra Nevada. The species has all but disappeared from over 50% of its historic range in the Sierra Nevada. Its most significant decline has been noted at lower elevations and at the western edge limit of its historical distribution. Many recent scientific studies have concluded that livestock grazing poses a serious threat to the Yosemite toad and has detrimental impacts through trampling, alteration of meadow habitat, changes in stream hydrology, siltation of springs, bacterial increase from livestock fecal matter, and lowered water quality. There is also evidence that chemical toxins and predation by introduced exotic fish have resulted in a decline in the Yosemite toad population. Remaining populations are thought to not be reproducing enough to survive. Vehicular traffic kills, prolonged periods of drought, and disease all claim partial responsibility in the rapid decline of the Yosemite toad and attempts are being made at various zoological institutions throughout the U.S. to successfully breed and reintroduce this species back into its native range.
Endemic to the Sierra Nevada the primary habitat of the Yosemite toad consists of ponds used as breeding areas and nearby meadows, often near pine forests, that provide food. Even though they spend most of their time on land, they are never far from a permanent body of water. In their juvenile stage, Yosemite toad tadpoles swim in shallow pools of melted ice water, and in slow moving mountain streams. They live primarily at high elevations, anywhere from 5,000 to 11,000 feet. These grassland amphibians burrow under the soil, crawl beneath rocks and fallen logs and seek shelter in abandoned rodent holes during the night.
The species name "canorus" means “tuneful” in Latin. This refers to the male’s sustained melodious trill, which attracts mates during the early spring breeding season. Listen to Yosemite toads singing, courtesy of Gary Nafis, author of A Guide to the Reptiles and Amphibians of California (www.californiaherps.com).
The Forest Service concluded in the original 2001 Sierra Nevada Framework Plan that the prescriptions and proposals contained therein provided the most effective management approaches for Yosemite toad persistence and recovery through the limitation of chemical toxins, removal of exotic fish, and reduction of livestock grazing in core toad habitat. The2004 revisions to the Framework do not take this low-impact strategy into account and actually ignore the prevailing science that concludes that grazing practices represent a significant threat to the future viability of the Yosemite toad in the Sierra Nevada. The 2004 revisions which serve as the current guidelines for the Forest Service do not provide for specific direction limiting livestock grazing and no changes to grazing policy have been made in Yosemite toad habitat.
Sierra Forest Legacy's Conservation Strategy, Appendix A, incudes recommendations for conservation of Yosemite toad that can be used to inform public involvement in forest management plan revisions now going forward on the Sierra National Forest and the Inyo National Forest.
In February, 2000, environmental groups submitted formal petitions with the U.S. Fish and Wildlife Service (USFWS) to protect the Yosemite under the Endangered Species Act. In late 2002 the USFWS concluded that it warrants protection under the Endangered Species Act. Unfortunately, the Service noted that budgetary constraints precluded them from listing the toad as threatened or endangered at the time. This decision was followed by more legal action seeking to force the Service from the delay in designating endangered status to the Yosemite toad. As of this writing, this imperiled species is still not listed under the Endangered Species Act and has also lost the proactive conservation measures prescribed in the original Sierra Nevada Framework following the revisions to that plan in 2004. It is currently a Forest Service Sensitive Species and a California State Species of Special Concern.
Update: April 25, 2013
The U.S. Fish and Wildlife Service today published a proposed rule to list the Yosemite Toad as a threatened species under the Endangered Species Act. Along with the designation, the FWS also proposed designation of critical habitat for the species' survival and recovery. Critical habitat has nothing to do with sealing off lands. Rather, when activities proposed by Federal land managers like the U.S. Forest Service fall within critical habitat boundaries, the recommended practices for conservation and recovery of the species will be followed. Threatened or endangered species status also means that U.S. Fish and Wildlife Service wildlife specialists are notified when federal agencies propose activities on public lands that might impact the species. Such designations rarely have any impact on private lands.
At the same time, the mountain yellow legged frog and Sierra Nevada yellow-legged frog were also proposed for listing as endangered species.
Davidson, C. and G. M. Fellers. 2005. Bufo canorus Camp 1916, Yosemite Toad. Pp. 400-401. Amphibian Declines: The Conservation Status of United States Species. Volume 2: Species Accounts. University of California Press, Berkeley, California. (156KB PDF)
Grasso, R.L., 2005. Palatability and Antipredator Response of Yosemite Toad (Bufo Canorus) to Nonnative Brook Trout (Salvelinus Fontinalis) in the Sierra Nevada Mountains of California. Masters Thesis, California State University, Sacramento. (666KB PDF)
Martin, D. L. 1991. Captive Husbandry as a Technique to Conserve a Species of Special Concern, the Yosemite toad. Fifth Conference on the Captive Propagation and Husbandry of Reptiles and Amphibians. Northern California Herpetological Society, University of California, Davis, CA. Pp.16-32 (1.55MB PDF)
Shaffer, H. Bradley, S.H., G.M. Fellers, A. Magee, and S.R. Voss. 2000. The Genetics of Amphibian Declines: Population Substructure and Molecular Differentiation in the Yosemite Toad, Bufo canorus (Anura, Bufonidae) Based on Single-strand Conformation Polymorphism Analysis (SSCP) and Mitochondrial DNA Sequence Data. Molecular Ecology 9, 245–257 (810KB PDF)
2013. USFWS Proposed Rule: Endangered Status for the Sierra Nevada Yellow-Legged Frog and the Northern Distinct Population Segment of the Mountain Yellow-Legged Frog, and Threatened Status for the Yosemite Toad, April 25, 2013 (606 KB PDF)
2013. USFWS Proposed Designation of Critical Habitat for the Sierra Nevada Yellow-Legged Frog, the Northern Distinct Population Segment of the Mountain Yellow-Legged Frog, and the Yosemite Toad, April 25, 2013 (1.8 MB PDF)