Sumas Lake today
Oregon Spotted Frogs were declared an Endangered species in Canada by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1999. The species is also Red-listed in B.C.
The primary cause for the decline of Oregon Spotted Frog has been the loss of wetlands as the Fraser River floodplain was drained for agriculture. The impact is even greater when agricultural land is further converted to housing and urban development.
The photos on the left are an example of what happened to Sumas Lake before and after agricultural development.
OSF must also compete with invasive species such as Bullfrogs and Green Frogs, and face the loss of their specialized breeding habitat due to invasive plant species like Reed Canarygrass.
Bullfrogs, native to Eastern Canada, were accidentally introduced to B.C. fifty years ago. These large frogs can eat Oregon Spotted Frogs and other smaller frogs, and wetlands where Bullfrogs are found have much smaller populations of native amphibians
Oregon Spotted Frog and other amphibians are also highly sensitive to pollutants because of their permeable skin. They are exposed to agricultural chemicals and pesticides used within the channel banks or unsafely stored adjacent to the watercourses.
The Oregon Spotted Frog is also susceptible to fungal diseases like Chytridiomycosis, which affects around 30 percent of the planet’s amphibian species. This disease is responsible for dramatic amphibian declines, and there is no known cure.