The International Union for Conservation of Nature (IUCN) recognizes the California red-legged frog (Rana draytonii) as vulnerable on the organization’s Red List of Threatened Species, but for populations specific to California’s Yosemite Valley, the circumstances were mere much direr.
Image Credit: Lisa M. Krieger via Mercury News
50-some-odd years went by during which the California red-legged frog was nowhere to be found in Yosemite, but conservationists took on a reintroduction effort in 2017 in an attempt to change that. Fortunately, those same conservationists are now witnessing the fruits of their efforts.
Just this Spring, ecologists working at Yosemite happened upon a sudden boom of egg clusters and tadpoles throughout the park’s waterways. The findings are particularly exciting to those familiar with the efforts because it’s the first evidence of actual breeding among the California red-legged frogs since the reintroduction efforts that took place in 2017.
"It's unusual to find eggs in any location and to find them this soon is a strong indication that red-legged frogs are adapting successfully to the riparian areas where we reintroduced them," explained Mike Reynolds, the superintendent of Yosemite National Park.
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Ecologists just recently released another captively-raised batch of young frogs into the region to boost their efforts, and they were coupled with small tracking chips that will let scientists gather detailed information about the species’ lifestyles and movement patterns.
Several factors contributed to the California red-legged frog’s vanishing act, including unsustainable harvesting (because people used to eat these things) and the introduction of a predatory bullfrog that developed a taste for the frogs. Fortunately, park staff removed these nuisances from the region, which should give the California red-legged frog a fair chance to rebound.
"The significance is if we can get the frogs established in Yosemite Valley, hopefully, we can use this as a pinch point to start releasing in other known historic localities," added Rob Grasso, the leader of the program.
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Thousands of captively-bred California red-legged frogs have since been released at Yosemite, and more are scheduled to be released sometime next month. Assuming these trends continue, Yosemite’s California red-legged frog populations could return to what they were before the 50-year disappearance.
If the success continues, then the team plans to reintroduce the California red-legged frog to other regions where numbers have dipped or disappeared.
Isn’t it just great when conservation efforts work out how they’re supposed to?
Source: Mercury News, USA Today, IUCN