Frogs and other amphibians use their skin for a number of vital functions including respiration and maintaining electrolyte balance. Unfortunately a virulent fungal disease called chytridiomycosis attacks the skin of certain frogs and disrupts its life-giving work. Chytridiomycosis rapidly spreads though populations and causes localized extinctions (called “extirpation”). Scientists are learning more and more about how this disease spreads within and between ponds.

Recent work by researchers at San Francisco State University and the San Diego Zoo has shown that a native frog species, the Pacific chorus frog, is immune to the effects of the disease even though it can be highly infected. Infected Pacific chorus frogs shed hundreds of zoospores of the lethal fungus per hour. Other frog species living alongside infected Pacific chorus frogs can catch the disease and their populations can quickly collapse.

At the A Rocha Canada Brooksdale Environmental Centre we are working with a threatened frog species in the Little Campbell River watershed – the northern red-legged frog. An endangered species, the Oregon spotted frog, may also be present and we are keeping an eye out for it in our survey work this year. Pacific chorus frogs are very common in the watershed. Other research indicates that the northern red-legged frog, like the Pacific chorus frog, does not seem to succumb to the effects of the fungus. Like the Pacific chorus frog, it may act as a reservoir host, spreading the disease to other more susceptible species. The Oregon spotted frog is not so lucky and chytridiomycosis spread to it by its frog neighbors may further impact its endangered populations.

Along with continually monitoring threats such as habitat degradation and ongoing nearby development within the Little Campbell River watershed, the A Rocha Canada conservation team will also have to keep an eye out for effects of this complex disease system.