Amphibians - Frogs and toads
The tailed frog is BLUE-listed. It is endemic to the Pacific Northwest and is the only frog in North America highly specialized for life in cold, clear mountain streams. Due to its specialized habitat requirements, it is vulnerable to habitat loss and alteration associated with logging. Logging impacts include stream exposure, increased silt, bank erosion and windfall, as well as reduced flow rates and substrate stability.
The tailed frog is found within coastal forests from sea level to near timberline (i.e., 5-1150 m in B.C.). It occurs in mountain streams, steep-walled valleys and coastal creeks. This long-lived species (15-20 yrs) displays three main life stages: tadpole, juvenile (transformed pre-reproductive), and adult (transformed reproductive). The tadpole stage may last two to four years depending on stream productivity and water temperature. Tadpoles remain at their natal stream feeding on diatoms and algae, which they scrape off the surface of rocks. Metamorphosed individuals feed primarily on terrestrial insects. Juvenile frogs may disperse to new streams before they reach sexual maturity at 7 or 8 years of age. Breeding occurs in early fall. Unlike most frogs, fertilization is internal. In July, females attach eggs (44-75 eggs/clutch) under stones in the water and will not breed again until the fall of the following year. Adults are very philopatric remaining near one breeding site their entire lives. Dispersal abilities are likely poor due to their philopatric nature and presumed limited juvenile dispersal.
Tailed frogs occur west of the Cascade Range, from northwestern California north to British Columbia. They also occur in northern Idaho and northwestern Montana. In B.C., this species occurs from Penticton north to Portland Canal (north of Prince Rupert). It may occur on near-shore coastal islands but does not occur on Vancouver Island or the Queen Charlotte Islands. There is also a disjunct population in the Flathead drainage in the Kootenays
COM: NWC, HEL, KIR, NAR, EPR, NPR, OUF, SPR
GED: FRL, GEL
SOI: LPR, PAR, HOR, OKR
CWH, ESSF, ICH, MH
CB, CH, CR, CW, DA, FR, FS, HB, HS, MF, RS, SM, SR, YB, YM, YS
6: mature forest (100-140 years)
7: old forest (>140 years)
Breeding and nursing streams are critical habitat for breeding adults and tadpoles. Due to a long larval development period, tadpoles require stable streams that are permanently flowing. Channel characteristics that will ensure channel stability are particularly important (e.g., bedrock and surficial materials). Streams or gullies composed of coarse substrates (boulders and large cobbles) and bedrock that breaks down into coarse rock (e.g., intrusive or highly metamorphic rock), may maintain a higher density of tadpoles. Coarse substrates enable tadpoles to escape flooding events and small bedload movements.
Generally, these streams do not contain commercial fish species or other aquatic predators. The streams must also be cool (0 to 16°C), as all life stages have narrow temperature requirements. Shade maintains low stream temperatures, and is probably also important for the survival of foraging adults, as incipient lethal air temperatures for adult frogs are between 22 and 24°C. Streams with these preferred characteristics adjacent to old forest with significant understorey may be particularly important for this species.
Blaustein, A.R., J.J. Beatty, D.H. Olson and R.M Storm. 1995. The biology of
amphibians and reptiles in old-growth forests in the Pacific Northwest. U.S. Dep. Agric., For. Serv. Gen. Tech. Rep. PNW-GTR-337. Portland, OR.
Brown, H.A. 1990. Morphological variation and age-class determination in overwintering
tadpoles of the tailed frog, Ascaphus truei. J. Zool. Lond. 220: 171-184.
Bury, R.B., P.S. Corn, K. Aubry, F.F. Gilbert and L.L.C. Jones. 1991. Aquatic amphibian
communities in Oregon and Washington. In Wildlife and Vegetation of Unmanaged Douglas-fir Forests. USDA For. Serv., Portland, OR. Gen. Tech. Rep. PNW-GTR-285. pp. 353-362.
Cederholm, C. 1994. Landscape approach for salmon and wildlife habitat protection. In
Washington Forest Landscape Management Project: Progress Report. USDA For. Serv., WA State Dep. Fish and Wildl., WA State Dep. Nat. Resour., WA.
Claussen, D.L. 1973. The thermal relations of the tailed frog, Ascaphus truei, and the
Pacific treefrog, Hyla regilla. Comp. Biochem. Physiol. 137-153.
Corn, P.S. and R.B. Bury. 1991. Terrestrial amphibian communities in the Oregon Coast
Range. In Wildlife and Vegetation of Unmanaged Douglas-fir Forests. USDA For. Serv., Portland, OR. Gen. Tech. Rep. PNW-GTR-285. pp. 305-317.
_____. 1989. Logging in western Oregon: responses of headwater habitats and stream amphibians. For. Ecol. and Manage. 29: 39-57.
Daugherty, C.H. and A.L. Sheldon. 1982. Age-specific movement patterns of the frog
Ascaphus truei. Herpetologica 38(4):468-474.
Dupuis, L.A. and F.L. Bunnell. 1996. Status and distribution of the tailed frog in British Columbia. B.C. Min. For., Nanaimo, B.C. Draft report-03/96.
Dupuis, L. and P. Friele. 1995. Riparian management and the tailed frog. B.C. Min. For.,
FEMAT. 1993. Forest ecosystem management: an ecological, economic, and social
assessment. Report of the Forest Ecosystem Management Assessment Team. U.S. Dep. Agric. and U.S. Dep. Inter., Portland, OR.
Metter, D.E. 1964. A morphological and ecological comparison of two populations of the
tailed frog, Ascaphus truei Stejneger. Copeia 1964:181-204.
Resources Inventory Committee. 1995. Sampling techniques for the tailed frog and the
Pacific giant salamander. B.C. Min. Environ., Lands and Parks, Wildl. Br., Victoria, B.C.
Richardson, J.S. and W.E. Neill. 1995. Distribution patterns of two montane stream
amphibians and the effects of forest harvest: the Pacific giant salamander and tailed frog in southwestern British Columbia. B.C. Min. Eniron., Lands and Parks, Victoria, B.C.
Welsh, H.H. and A.J. Lind. 1991. The structure of herpetofaunal assemblage in the
Douglas-fir/hardwood forests of Northwestern California and Southwestern
Oregon. In Wildlife and vegetation of unmanaged Douglas-fir forests. USDA For. Serv. Portland, OR. Gen. Tech. Rep. PNW-GTR-285. pp. 395-414.