From the NatureWatch website, which is a community site that "engages all Canadians in collecting scientific information on nature to understand our changing environment."

From the FrogWatch home page:
"Worldwide, many wetland species are declining in numbers or have recently become extinct. Monitoring frog and toad populations is one way to check the health of wetland areas.

    Frogs and toads can be used as indicator species, because they are vulnerable to changes in the atmosphere, the land, or the water.

Tracking changes in the population of frogs and toads in Canada, their geographic range, and the beginning and ending of their calling season can help us understand what is happening in their environment. The most effective way to track changes in frog and toad populations is to listen for their calls during mating season in the springtime."

Visit the Frog Watch British Columbia web page.