PREDATION ON CALIFORNIA RED-LEGGED FROG EGGS BY OVERWINTERING ROUGH-SKINNED NEWT LARVAE
|Karen M Kiemnec-Tyburczy; Cal Poly Humboldt; firstname.lastname@example.org; Emma Nix, Michael Westphal
In the winter of 2017 we transferred 20 egg masses of the California red-legged frog, Rana draytonii, a species listed as ‘threatened’ under the Federal Endangered Species Act, into a small pond in coastal Santa Cruz County, California. We unexpectedly discovered large larval salamanders devouring the eggs. Sampling that spring and summer showed no R. draytonii tadpoles in the pond. Mitochondrial DNA indicated that the salamander larvae were rough skinned newts, Taricha granulosa. Continued sampling throughout 2018 and 2019 found both larval T. granulosa and the California newt, T. torosa, to be present in the pond, but larval T. granulosa alone was present throughout the winter months. Predation by overwintering T. granulosa larvae constitutes a previously unreported ecological pressure on R. draytonii and thus may have a significant effect on recovering this sensitive species.