The union between the native California tiger salamander and the non-native barred tiger salamander, which was brought in huge numbers from Texas beginning 60 years ago by California bait dealers [The New York Times], has produced an alarming hybrid offspring. A new study of the hybrid’s behavior in artificial ponds serves as a reminder that invasive species can alter ecosystems in unexpected ways: in this case, by getting too cozy with the natives of central California.
The new hybrid “superpredator” grows larger than either of its parent species, and its bigger mouth enables it to suck up a wide variety of amphibian prey, said lead study author Maureen Ryan…. Mostly on the menu are smaller pond species, such as the Pacific chorus frog and the California newt—both of which were “dramatically reduced” in population by the hybrid in the experiments [National Geographic News].
In the study, published in the Proceedings of the National Academy of Sciences, the researchers found that in its larval stage, the hybrid salamander devoured tadpoles and larvae of many amphibian species, including the larvae of the native tiger salamander, an endangered species. “The implication is they’re ecologically quite different than the native species,” Ms. Ryan said. That could spell trouble for other “third-party” species in the [Salinas] valley, like the California red-legged frog and the Santa Cruz long-toed salamander [The New York Times], if the hybrid continues to spread through the area.
The question of what to do about the hybrid and its hungry, hungry ways poses an ethical quandary for conservationists, says Ryan. After all, the hybrid is part endangered species, so “do we protect [them] because they’re part native?” Overall, Ryan said, her “real concern” is for the survival of California’s native salamander, which has shown to be no match for the half-Texan interloper. The hybrid’s more aggressive predation “benefits the hybrid and harms the native, speeding up the process of converting populations into more hybrids” [National Geographic News].
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Image: Brian MacElvaine