Amphibians and Reptiles in the AOSERP Study Area

During June, July, and August of 1976 three species of amphibians were found within the Alberta Oil Sands Project area. The wood frog (Rana sylvatica) was the most abundant and widespread species and was collected at each of 20 sites examined. Boreal chorus frogs (Pseudacris triseriata maculata) and Canadian toads (Bufohemiophrys) were common but found at less than half of the study sites. All three species had spawned prior to 12 June. Natural ponds and borrow pits were the most frequently used spawning sites. Canadian toads also spawned in flowing water and lake margins. All species had metamorphosed by early August. Wood frogs metamorphosed at a mean snout-vent length of 17.2 mm, Canadian toads at 12.4 mm, and boreal chorus frogs at 13.7 mm. Spawning for each of these species probably does not occur until individuals are in their third summer of life. Population densities of wood frogs, boreal chorus frogs, and Canadian toads reached estimated maxima of 19.6, 2.3, and 12 per 1000 m2 during 1977. Maximum densities of all species were found within 50 m of the nearest body of water in moist habitat vegetated by sedges, grasses, horsetails, willows and poplar. Lower densities were found in upland mixed woods and no anurans were found in dry areas with sandy substrate and jack pine forest. Other amphibian species and reptiles are either absent or only locally abundant.