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New study provides detail on the range of habitats used by the Oregon spotted frog in the fall, and suggests areas for further work to improve survival of this threatened species in reservoirs with abundant fish predators.

Reservoirs can provide habitat for amphibians but their water level fluctuations and non-native predators pose challenges to wildlife compared to more natural habitats. USGS researchers compared fall movement and habitat use by Oregon spotted frogs in Crane Prairie reservoir with nearby river and pond habitats in central Oregon. Frogs in rivers and ponds settled into inactivity or very small ranges by mid-fall, shifting to areas protected from freezing and predators. Frogs in the reservoir continued moving even as water temperature cooled and did not shift habitats. Reservoir frogs were found in aquatic vegetation throughout the fall, which could indicate cover use for protection from fish predators. Crane Prairie is one of few reservoir habitats that has supported Oregon spotted frogs for decades. Understanding how Oregon spotted frogs use habitat here provides insight on how they persist in managed habitats with predators and can inform the design of habitat restoration efforts to benefit the species. 

Pearl, C.A., Rowe, J.C., McCreary, B., and Adams, M.J., 2022, Late season movement and habitat use by Oregon spotted frog (Rana pretiosa) in a large reservoir in Oregon, USA: Journal of Herpetology, v. 56, no. 1, p. 8-17