Tailed Frogs (Ascaphus truei)
The Tailed Frog is a long-lived frog with a stream-dwelling tadpole stage and a typically terrestrial juvenile and adult stage. During its long tadpole stage, which may last up to four years in some parts of its range, it feeds on the algae and biofilm growing on the surfaces of large rocks on stream bottoms. The most typical habitat for the tadpoles is in fast-flowing streams with rocky substrate. Adults are most often encountered close to stream margins, but can be found hundreds of metres away from the nearest stream.
The range of the species extends from northern California to the southern tip of the Alaska panhandle. A large portion of the species’ range is within BC. In BC the Tailed Frog is on the province’s Blue List as a species that is potentially threatened. The main supposed threat is from changes to streams and surrounding forests by logging activities. Our studies are designed to determine the nature and the magnitude of the risks to the species posed by forestry, and also to provide important information on the general ecology of the species.
There are several components to our overall studies including:
- the effects of logging on tadpole growth
- movements of adults and juveniles in clearcut and forested areas
- choice of tadpole substrate habitats by sizes of rocks
- risk assessment using computer modelling
- long-term population censuses
- density dependence of tadpole growth, and algae as a limiting food resource