Humboldt State University



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dc.contributor.advisor Waters, James F. Twedt, Brian 2018-05-18T21:27:06Z 2018-05-18T21:27:06Z 1993-05
dc.description Thesis (M.A.)--Humboldt State University, Biology, 1993 en_US
dc.description.abstract Populations of Rana aurora Baird and Girard (red-legged frog) and Rana catesbeiana Shaw (Bullfrog) were studied at Freshwater Lagoon from December 1990 through January 1991. Significant differences in habitat-use between species were confirmed using log-linear analysis. I found red-legged frogs most often on land, while bullfrogs were found most frequently in the water. An analysis of the stomach contents of bullfrogs provides proof that bullfrogs prey on red-legged frogs at Freshwater Lagoon. Bullfrogs were shown to also feed on the highly toxic Taricha granulosa (Skilton) (rough-skinned newt). I examined the seasonal activities of both species, and I found that adult male and sub-adult red-legged frogs are absent from the lagoon after bullfrogs emerge from hibernation. Interspecific amplexus between male red-legged frogs and sub-adult and juvenile bullfrogs was observed on 31 separate occasions. Estimates of the population structure of bullfrogs confirm that it is well established at Freshwater Lagoon. Although the differences in habitat use between red-legged frogs and bullfrogs at Freshwater Lagoon appear to be great enough to alleviate the effects of predation and interspecific amplexus on the population of red-legged frogs, the two populations should be monitored through time to see if they are increasing or decreasing relative to one another. en_US
dc.language.iso en_US en_US
dc.publisher Humboldt State University en
dc.subject Freshwater Lagoon en_US
dc.subject Bullfrogs en_US
dc.subject Red-legged frog en_US
dc.subject Ecology en_US
dc.title A comparative ecology of Rana aurora Baird and Girard and Rana catesbeiana Shaw at Freshwater Lagoon, Humboldt County, California en_US
dc.type Thesis en_US
dc.program Biology en_US

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