Study: Livestock not culprit in Yosemite toad decline
By Pat Bailey, UC Davis
Livestock grazing is apparently not the culprit in the steep decline of Yosemite toads and their habitat, according to the results of an extensive, five-year study conducted by UC Davis, UC Berkeley and the U.S. Forest Service.
“A direct correlation between the intensity of cattle use and toad occupancy of meadows was not found for any portion of the grazing season — early, mid or late,” said Leslie Roche, a UC Davis Department of Plant Sciences graduate student who worked on the study.
Results from the study will impact ranchers whose grazing allotments were restricted by the U.S. Forest Service in 2001 based on the assumption that grazing is contributing to the toads’ decline. Forest Service officials will use the study to develop plans that allow grazing within appropriate standards while conserving toads.
The researchers had hypothesized that a reduction in grazing intensity would stop or even reverse the decline of the Yosemite toad but, in fact, they found no evidence to support that premise.
“Results strongly indicate that toad presence is driven by meadow wetness rather than cattle utilization,” said Roche, who is completing her doctoral dissertation on this project.
