Yosemite toad and cattle use the Sierra Nevada landscape differently

A five-year study of Yosemite toad populations in an area fenced off from cattle has shown that exclusion from grazing doesn't help the endangered amphibian, reported Kate Campbell in AgAlert.

"The toads use water areas and the cattle use drier meadow areas, which provide better forage," said Ken Tate, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis.

The study, "Determining the Effects of Cattle Grazing Treatments on Yosemite Toads in Montane Meadows," found "no benefit of fencing to Yosemite toad populations." Researchers said their results "do not support previous studies that found a negative impact of grazing on amphibian populations."

The Yosemite toad was once among the most prevalent amphibians in the high Sierra including Yosemite National Park, where it was first discovered and after which it is named, according to a UC Davis news release. But its population and habitat has declined sharply since the early 1980s, disappearing from much of its historic range — meadows at elevations between 6,500 and 11,500 feet from Alpine to Fresno counties.

Besides grazing, other possible reasons for the amphibian's decline include habitat modifications, disease, invasive species, climate change and pesticides, the AgAlert article said.

Combined with other recent studies of water quality and meadow vegetation grazed areas, the research shows that conditions are improving and compatibility between livestock production and other ecosystem services provided by forests are increasing, Tate said.

More information about the studies can be found on the Rangeland Watershed Laboratory website.

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