Coastal Tailed Frog – State Wildlife Action Plan

Coastal Tailed Frog

Photo Credit: U.S. Fish and Wildlife Service

Coastal tailed frogs are adapted to mountain streams with flattened bodies, hardened toes on the front feet, and long back legs. They have vertical pupils and lack external ear drums. The coloration of coastal tailed frogs varies from olive, green, or reddish with gray or yellow mottling. There is a pale yellow or greenish triangle between the snout and eyes. Their pupils are vertical, and they have dark, horizontal eye stripe. Adults grow up to an average of one to two inches in length, snout to vent, with adult females averaging 50% larger than males. Males have a small tail, for which the species is named. The tadpoles are slate gray to brownish gray and covered in black flecks, with a white dot on the tip of the tail, and a copper colored bar between the snout and eyes. Their bodies are flattened, and they have mouths oriented on the underside of their body that allow them to adhere to rocks in fast flowing water.

Overview

  • Species Common Name Coastal Tailed Frog
  • Species Scientific Name Ascaphus truei
  • Federal Listing Status Species of Concern
  • State Listing Status Sensitive

Ecoregions

    Special needs

    Coastal tailed frogs are found in cold, clear, fast-flowing streams within forested areas. Adults need streambanks, logs, headwater springs, and gravelly seeps for foraging and hiding, and small boulders in streams for egg-laying. Tadpoles require permanent streams with moss- and sediment-free cobble and boulder substrate for clinging to rock surfaces while scraping diatoms and algae. In the Coast Range, this species may be limited to streams with hard-rock substrate rather than sandstone.

    Limiting factors

    This species has a restricted range (Pacific Northwest endemic), low reproductive rate (several-year larval stage), and limited dispersal capabilities (remaining near water sources), all of which may hamper recovery. Sedimentation and increases in water temperature are further risk factors. Climate change may further threaten habitats occupied by tailed frogs.

    Conservation actions

    • Retain stream buffers to create complex forest structure and maintain cool water temperatures and water clarity.
    • Minimize sediment coating or embedding of rocky substrates.
    • Use results of dispersal studies to guide recommendations on culvert size or modification.
    • Retain course woody debris to protect and promote wet microsites.
    • Retain areas of late seral forests to provide connectivity and dispersal habitat.

    Key reference or plan

    CaliforniaHerps.com Coastal Tailed Frog – Ascaphus truei Read here

    Olson, D. H., and A. Ares (2022). Riparian buffer effects on headwater-stream vertebrates and habitats five years after a second upland-forest thinning in western Oregon, USA. Forest Ecology and Management 509:120067 Read here

    Management Plan for the Coastal Tailed Frog (Ascaphus truei) in Canada Read here

    Resource selection and movement of the coastal tailed frog in response to forest harvesting Read here

    California Interagency Wildlife Task Group – Coastal Tailed Frog Read here

    Life History Traits