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Amphibians and Reptiles

Western toad in the upper watershed

Western toad in the upper watershed.

Amphibian and reptile species are found throughout the watershed in a variety of habitat types including forests, streams, talus slopes and ponds and wetlands.

Overview

Most amphibians (frogs, toads, and salamanders) begin their lives in water and undergo “metamorphosis” when they develop into a form that can survive solely on land. The land-dwelling adults return to the water to lay eggs.

This requirement for both aquatic and terrestrial habitat to complete their life cycle distinguishes amphibians from other vertebrate animals. There are some exceptions to this pattern, however. Several species of salamanders lay eggs on land in the forest and do not need water in their larval stage.

Reptiles are generally terrestrial animals. There are relatively few reptile species in the Pacific Northwest coastal ecoregion, compared to warmer, drier areas like eastern Washington.

Eleven species of amphibians and three species of reptiles are known to occur in the watershed.

Below is a list of amphibians and reptile species found in the Cedar River Watershed, listed by habitat in which they breed.

Ponds/Wetlands/Lakes

  • Northwestern salamander
  • Long-toed salamander
  • Roughskin newt
  • Western toad
  • Red-legged frog
  • Cascades frog
  • Pacific treefrog

Forests

  • Ensatina
  • Western redback salamander
  • Northern alligator lizard
  • Northwestern garter snake
  • Rubber boa

Streams

  • Pacific giant salamander
  • Tailed frog

Lake and Pond Breeding

Two wetland systems in the lower watershed are heavily used by frogs and salamanders for breeding: 14 Lakes and a beaver-controlled wetland system along Rock Creek. See Map of amphibian presence by site in the lower Cedar River Watershed (pdf).

14 Lakes is a series of groundwater-fed kettle ponds that have no inflowing or outflowing streams. These ponds do not contain fish, which can eat amphibian eggs, developing tadpoles, and larvae, thus sharply reducing amphibian populations.

Amphibians that consistently breed in 14 Lakes include:

  • northwestern salamanders
  • long-toed salamanders
  • roughskin newts
  • red-legged frogs
  • Pacific treefrogs

At 14 Lakes, large numbers of tadpoles of these species can be observed at the pond edges in early summer. Later in the season, juvenile red-legged and Pacific treefrogs are numerous around the perimeter of each pond. The chorus of Pacific treefrogs is ever present at 14 Lakes.

The Rock Creek wetland system supports the same species as 14 Lakes, but is a very different kind of wetland. This wetland system consists of a series of beaver ponds intercepting a perennial stream. Removal of a 1.5 mile road through this wetland system in 2002 helped reconnect the habitat for amphibians and other animals.

In the upper watershed, amphibian breeding is supported in numerous high elevation wet meadows and ponds (none of which have fish populations).

The most common amphibian species breeding in these areas are:

  • Cascades frogs
  • northwestern salamanders
  • Pacific treefrogs

Stream Breeding

Tailed frogs and Pacific giant salamanders breed in streams in both the upper and lower watershed.

Tailed frogs lay eggs under cobble-sized substrate in steep, small streams. The eggs hatch and tadpoles rear in the streams for at least two years before metamorphosing and moving into the forest.

In order to hold onto rocks in the fast-flowing stream, tailed frog tadpoles have a modified mouth—a downward turned disk that suctions on the rock’s surface. They graze on algae as they move over the surface of a particular rock.

Larval Pacific giant salamanders generally are found in quiet water, underneath boulders or logs or in deeper pools. Metamorphosed adults also stay well hidden, occurring along the stream edge or well into adjacent forests. Individuals of this species can reach a size of 14 inches total length.

Distribution

A total of 60 wetland sites were surveyed for pond breeding amphibians in the watershed. Northwestern salamanders and Pacific treefrogs were the most commonly documented species, found at 59 percent and 61 percent of the sites surveyed in the Cedar River Watershed, respectively.

The next most common species was the Cascades frog, present at more than 50 percent of sites surveyed. The Cascades frog is commonly found along stream corridors, in wet meadows, and around larger ponds and lakes above 2,000 feet elevation in the watershed.

The species documented at the fewest sites in the watershed is the western toad, confirmed breeding only in Chester Morse Lake and present at only four wetland sites. Migrations of western toadlets occur late each summer after the tadpoles metamorphose. Masses of toadlets are often observed on watershed roads and bridges as they move to upland habitat from Chester Morse Lake. Most frequently toadlets follow stream corridors as a migration route between ponds and upland habitat.

Threats

Amphibians in the Cedar River Watershed are generally protected from threats associated with urban development and pollution from urban environments.

A potential threat that preys on native amphibians and can dramatically reduce their populations is the bullfrog, a non-native amphibian species in western Washington. To date, bullfrogs have not been found anywhere in the watershed.

Forests in the Cedar River Watershed are protected under the Habitat Conservation Plan and are managed to promote the development of mature forest habitat. This management strategy protects and enhances existing upland forest habitat for amphibians and reptiles in the watershed. When planning thinning projects for restoring forest habitat in the watershed, City biologists carefully consider upland habitat surrounding lakes and ponds to ensure that amphibian habitat is not impacted.

Studies show that global climate change can negatively impact amphibians through reduction in water levels at breeding ponds and increased UV-B exposure. Amphibians in the watershed will face these challenges along with all species in the region.

For more information contact sally.nickelson@seattle.gov.

Reports and Maps

Related Links