Species of special interest
Amphibians are an integral part of aquatic food webs, feeding on algae and insects at different life stages and serving as food for a wide range of predators, including dragonflies, fish, snakes, and birds. They are particularly sensitive to pollutants absorbed through their skin, which makes them good indicators of wetland contamination and degradation.1
In the Great Lakes Basin, four amphibian species, American toad, western chorus frog, northern leopard frog, and green frog, may have declined since the mid-1990s. Spring peeper is the only species out of eight monitored that has been increasing. However, the timeline is too short to be certain that these are long-term trends and not part of natural variation.1 In the St. Lawrence River, 27% of amphibians and reptiles are at risk within the highly developed river corridor.2 The northern leopard frog is considered Threatened in Alberta, red-listed in B.C., and assessed as Endangered (Rocky Mountain population), Special Concern (Western Boreal/Prairie populations) or Not At Risk (Manitoba and eastern populations) by COSEWIC.3
Batrachochytrium dendrobatids (Bd), a chytrid fungus of the skin, has been implicated in worldwide amphibian declines4 (see Invasive Non-native Species). Ranaviruses have also been responsible for mass die-offs of amphibians worldwide.5 Canada’s Boreal Shield,6 Prairies,7 and Mixedwood Plains6, 8 ecozones+ have documented cases of ranaviruses.
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