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1. We have used a stochastic population model with immigration to calculate extinction rates for two amphibian species: the common toad, Bufo bufo, and the crested newt, Triturus cristatus. 2. Population models for amphibians are difficult to parameterize. It was not possible to measure all the relevant parameters for the model. The other parameters were obtained from other studies or estimated on the basis of similar species. 3. Contour maps for persistence were generated using the model. The persistence of populations associated with a pond is affected both by the pond's internal dynamics and its proximity to a source pond. On a 20-generation time scale, toad ponds that were initially occupied were relatively unaffected by the proximity of a source. Persistence was almost certain (> 95%) when the average carrying capacity of a pond was greater than 30 adult females. Initially unoccupied toad-ponds were …