Western toad (Bufo boreas) COSEWIC assessment and status report: chapter 10

Special Significance of the Species

Given the status of Western Toad populations in the southern half of its range, Canadian populations represent the remaining stronghold of this species. We have an opportunity to begin monitoring and protecting this species before numbers fall below critical levels.

Bufo boreas is one of the widest ranging amphibians found within B.C., and it occurs at higher elevations than other amphibian. In this way it contributes significantly to the ecological processes of high elevation and high latitude wetlands. The sheer volume of Western Toad tadpoles contributes significantly to the biomass of wetland ecosystems: the eggs and tadpoles are consumed by many aquatic invertebrates and vertebrates and the tadpoles feed on large quantities of algae. Western toads are capable of ingesting large quantities of food and thus are a significant player in terrestrial, especially riparian, food webs, effectively converting items of low food value to a biomass more readily available to reptiles, birds and mammals (Feder 1983), and possibly maintaining lowered populations of some insect pests. Thus, declines in widespread, common species such as B. boreas can have big repercussions on ecosystem functioning (Corn 1994).

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