Native Turtles Are Back In Yosemite and It All Started Because Scientists Removed Another Species
Native wildlife species at certain places face population decline, often when there is a disturbance in their natural balance. Factors like loss of their natural habitat, rapid climate change, rising pollution levels, and competition from invasive species contribute to the struggle for survival of the native species. To protect them, it requires careful conservation efforts. For instance, it has been reported that for the first time in several decades, Yosemite has now been welcoming back its native turtles. This was possible because, after years of struggle, conservationists have successfully removed the invasive bullfrogs from the area.
Bullfrogs, originally found in the eastern United States, were introduced to the western habitats a few years ago, where they soon became a threat. These large species prey on native turtles and other small creatures, disrupting the balance and driving down the numbers of the native species. As reported by SciTech Daily, Brian Todd, a professor in the Department of Wildlife, Fish, and Conservation Biology, spoke about the bullfrogs and said, “One reason American bullfrogs are among the top worst globally introduced pests is because they eat everything – anything that fits into their mouth.”
He added, “They’ve been causing declines to native species everywhere they’re introduced, which is around the world.” A UC Davis Ph.D. candidate, Sidney Woodruff, also spoke about this and said, “At night, you could look out over the pond and see a constellation of eyes blinking back at you. Their honking noise is iconic, and it drowns out native species’ calls.” Woodruff is also a lead author of the study titled 'Effects of invasive American bullfrogs and their removal on Northwestern Pond turtles.' It was published in the May issue of the journal Biological Conservation. It claims that the ponds of Yosemite now sound much different, with the native turtles now being heard.
The success proves that eliminating bullfrogs from key conservation sites can play a crucial role in giving the turtles a chance to rebound, as reported by UC Davis. The study was conducted over a period of seven years, from 2016 to 2022. Researchers regularly tracked the pond turtle populations across four locations in Yosemite National Park. Two of these sites continued to have bullfrogs, while the other two had none, allowing experts to compare how the turtles survived under different conditions. It was observed that in the areas with bullfrogs, only large adult turtles survived, while the younger ones were eaten.
Researchers found little turtles and other small animals in bullfrog stomachs. Juvenile turtles appeared at the other two ponds only after bullfrogs were nearly eradicated in 2019. Meanwhile, experts claim that the western pond turtles play a major role in keeping the aquatic ecosystems healthy, but they are now proposed as a threatened species. Todd said, “All across the state, we have one native freshwater turtle, and it’s the western pond turtle. If it disappears, we have no other freshwater turtles that are supposed to be here. It’s part of our natural heritage.”
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