Rapid population growth in the Puget Sound region of Washington has led to the disappearance, alteration, and isolation of seasonally-flooded wetlands that provide breeding habitat for amphibian populations. To conserve amphibians in this rapidly changing landscape, it is important to understand basic habitat associations. We surveyed 48 seasonally-flooded wetlands for egg masses and larvae of all aquatic-breeding amphibians during 2008 and 2009. We collected field measurements of local wetlands characteristics—Including emergent vegetation, wetland depth, wetland shallow areas, and presence of the invasive American bullfrog—and quantified landscape patterns—Including urban development, forest cover, wetland density, distance to nearest permanent water body and forest patch—surrounding each surveyed wetland using remotely sensed data from 1995 and 2007. We used an information theoretic approach (AICc) to rank and evaluate a set of explanatory models for each species.

Results/Conclusions

The resulting models varied between species, all but one included both local- and landscape-level factors. Wetlands occupied by the northwestern salamander (Ambystoma gracile) were also occupied by the American bullfrog (Rana catesbeiana), were negatively associated with deciduous mixed forest and were located close to permanent water bodies. Occurrence of long-toed salamander (Ambystoma macrodactylum) was negatively correlated with historical forest cover factors, wetland density, and to the distance to the nearest forest patch. Wetlands occupied by Pacific treefrog (Pseudacris regilla) had a greater proportion of emergent vegetation, had less medium urban development, and did not have fish. Wetlands occupied by the northern red-legged frog (Rana aurora) were also occupied by the American bullfrog. The wetlands in which the northern red-legged frog occurred also had a greater proportion of shallow areas and had a smaller proportion of historical high urban development. Wetlands occupied by the American bullfrog were deeper and had less proportion of both, low urban density and cleared for development cover. Our results suggest that multiscale landscape patterns likely play a role in determining breeding habitat for these amphibian species and that in some cases, there may be a lag between land-use changes and the response of amphibians.