The population of Woodhouse's toad in Washington is unknown. The status of this species in Washington is based on the small number of populations, a limited distribution restricted to shrubsteppe habitat in a region heavily altered for agriculture and urban development (such as the Tri-Cities area), and a lack of information about the species.
Description and Range
This terrestrial toad is medium to large, averaging about 2 to 5 inches in length from snout to its vent (excretory opening). This stout toad has a broad waist, short legs, a round head, and a short snout. The skin is warty and large, long external skin glands (parotoid) are on the neck. Coloration is gray, light brown, or olive with dark blotches and spots and a dark speckled light underside. The back has a white stripe. Males have a dark throat. Tadpoles are small (less than about 1 inch total length). They are dark in color with light and golden pigment under the base of the tail.
Ecology and life history
Habitats include riparian areas, shrubsteppe, and grassland. Woodhouse's toads are found in shrubsteppe habitat near the Columbia and Snake rivers. Transformed toads are terrestrial, and soil types suitable for burrowing are important because the toads spend most of the day burrowed below the surface.
These toads are opportunistic predators who primarily eat invertebrates such as insects.
Activity starts in late April to early May and continues into Oct. Adult activity usually occurs during the twilight hours into the night, though smaller toads and newly metamorphosed "toadlets" can occasionally be found during the day. Male chorusing and breeding in Franklin, Benton, and Grant counties occurs from May into July depending on conditions at each breeding site.
Breeding takes place in a variety of still-water habitats, including shallow temporarily flooded sites, ponds, and sloughs. The toads will also lay eggs in stagnant areas of small, slow-flowing streams.
Eggs are laid in strings often mixed with eggs from other toads. Individual eggs are small, and black above and white below. Egg development to hatching is rapid (less than 10 days), and tadpole development is completed in approximately two months, while metamorphosis occurs in summer or fall of the first year.
In Washington, Woodhouse's toads occur in a small area of the Columbia Plateau Ecoregion along the Snake River, and along the Columbia River between the Priest Rapids Dam and John Day Dam. Occurrences have also been documented in the Eltopia and Wahluke Branch irrigation canal system in Franklin County on the Hanford site and Juniper Dunes.
The map illustrates potential range and habitat distribution of this species in Washington. For worldwide distribution and other species' information, check out NatureServe Explorer.
Sensitivity to climate change
Juvenile toads avoid high temperatures and prefer lower temperatures when food is limited or under dry conditions. Tadpoles may be sensitive to low pH levels. Woodhouse's toad may be better adapted to warmer, drier conditions due to their dry, leathery skin and ability to burrow to reduce exposure to high temperatures although they need suitable (i.e., friable) soils to burrow. Sensitivity of Woodhouse's toad is greater due to their habitat specialization (e.g., shrublands) and dependence on wetlands/ponds for breeding as well as low ability to disperse. Declines in shrub-steppe and wetland habitats due to climate change (i.e., changes in precipitation, invasive weeds, altered fire regimes) negatively affects this species.
Exposure to climate change
- Increased temperatures
- Changes in precipitation
- Increased invasive weeds
- Altered fire regimes
Conservation Threats and Actions Needed
- Resource information collection needs
- Threat: Lack of information on status and distribution.
- Action Needed: Research, surveys, and monitoring to understand species distribution and status.
- Threat: This species has limited distribution in Washington.
- Action Needed: Research, surveys and monitoring to understand species distribution and status.
- Threat: Little is known about the habitat requirements of this species in Washington.
- Action Needed: More information is needed on this species to understand its status and habitat management.
- Fish and wildlife habitat loss or degradation
- Threat: Loss and degradation of suitable shrubsteppe habitat that this species relies upon in Washington.
- Action Needed: Protect native shrubsteppe habitat from conversion and degradation due to agriculture.