occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) Native historical range extended from southern Mendocino County in northwestern California south (primarily west of the Cascade-Sierra crest) to northwestern Baja California (Shaffer et al. 2004). Historical populations on the floor of the Central Valley may not have persisted due to extensive natural flooding (Fellers, in Lannoo 2005). Range is now much reduced in the Sierra Nevada and in southern California, but the species is still present throughout much of its former range in the central California coast range (Fellers, in Lannoo 2005). This species has been introduced in a few places in Nevada, but the current status of those populations is uncertain (A. Cook, cited by Fellers, in Lannoo 2005). Rana draytonii is still present in Baja California, Mexico (USFWS 2000, Grismer 2002, Shaffer et al. 2004). Elevational range extended from sea level to about 1,500 meters (5,000 feet); usually below 1,200 meters (3,935 feet).

Differs from subspecies aurora in having more dorsal spots (usually with light centers), rougher skin, shorter limbs, and smaller eyes (Stebbins 1985); also averages larger (by 35-40 mm) in adult SVL (usually 8-14 cm vs. 5-9 cm) (Hayes and Miyamoto 1984).

• Terrestrial
• Freshwater

Comments: This species usually occurs in or near quiet permanent water of streams, marshes, ponds, lakes, and other quiet bodies of water. In summer, frogs estivate in small mammal burrows, leaf litter, or other moist sites in or near (within a few hundred feet of) riparian areas (Rathbun et al. 1993, cited by USFWS 1994; USFWS 1996). Individuals may range far from water along riparian corridors and in damp thickets and forests. Breeding occurs in permanent or seasonal water of ponds, marshes, or quiet stream pools, sometimes in lakes (Fellers, in Jones et al. 2005); eggs often are attached to emergent vegetation, float at surface (Hayes and Miyamoto 1984).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Based on movements of Rana draytonii, USFWS recognized the primary constituent elements for critical habitat to be, at a minimum, two (or more) suitable breeding locations, a permanent water source, associated uplands surrounding these water bodies up to 150 m from the water's edge, all within 2 km of one another and connected by barrier-free dispersal habitat that is at least 150 m in width. When these elements are all present, all other suitable aquatic habitat within 2 km, and free of dispersal barriers, is also considered critical habitat. This is based on individuals of this subspecies moving up to 3.6 km in a virtual straight line migration from nonbreeding to breeding habitats (Federal Register, 11 September 2000).

Comments: Diet includes various terrestrial and aquatic invertebrates, mainly invertebrates of shoreline or water surface. Diet of large adults also includes small vertebrates. Larvae eat algae, organic debris, plant tissue, and other minute organisms.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 - 300

Comments: Number of distinct occurrences (subpopulations) is unknown but probably is at least several dozen. According to USFWS (2000), the species occurs in about 238 streams or drainages.

In the mid-1990s, most of the occupied habitat was in Monterey, San Luis Obispo, and Santa Barbara counties; the species occurred in only 5 sites south of the Tehachapi Mountains (80+ historic sites) (USFWS 1996) Aggregations including more than 350 adults were known only from Pescadero Marsh Natural Preserve in coastal San Mateo County, Point Reyes National Seashore in Marin County, and Rancho San Carlos in Monterey County (USFWS 1996). More than 120 breeding sites exist in Marin County (Fellers, in Lannoo 2005).

In California, south of Los Angeles, a single population is known from the Santa Rosa Plateau in Riverside County (Shaffer et al. 2004). Only two populations are known to exist south of Santa Barabra (Fellers, in Lannoo 2005).

In the Sierra Nevada, Rana draytonii is now represented by only about a half dozen populations, only one of which is known to have more than 10 breeding adults (Shaffer et al. 2004).

10,000 - 100,000 individuals

Comments: Total adult population size is unknown but undoubtedly exceeds 10,000. The species is still locally abundant in portions of the San Francisco Bay area and the central coast (USFWS 2000). Breeding sites in Marin County include several thousand adults (Fellers, in Lannoo 2005).

Comments: Inactive in cold temperatures and hot, dry weather. May be active all year in coastal areas, inactive late summer to early winter elsewhere (Zeiner et al. 1988). Adults and subadults apparently mainly nocturnal; juveniles active day or night (Hayes and Tennant 1985).

Breeds typically during or shortly after large rainfall events in late winter or early spring (Hayes and Miyamoto 1984, USFWS 1996). In southern California breeds January-July (primarily in February). Breeding period lasts about 1-2 weeks. Eggs hatch in 6-14 days. Larval mortality tends to be very high. Larvae metamorphose 3.5-7 months after hatching; sometimes they may overwinter (Fellers et al. 2001). Sexually mature in 3-4 years, may live 8-10 years.

United States

Rounded National Status Rank: N2 - Imperiled

Rounded Global Status Rank: G2 - Imperiled

Reasons: Restricted mostly to California, where populations have declined greatly due to habitat loss and degradation, past overexploitation, and introduced species; species continues to be threatened by habitat degradation and exotic species.

Intrinsic Vulnerability: Moderately vulnerable

Environmental Specificity: Moderate. Generalist or community with some key requirements scarce.

Global Short Term Trend: Decline of 10-30%

Comments: Currently, area of occupancy, number of subpopulations, and population size probabaly are still declining, but the rate of decline is unknown.

Global Long Term Trend: Decline of 50-70%

Comments: Over the long term, extent of occurrence, area of occupancy, number of subpopulations, and population size have undergone a major decline. The species has been extirpated from much of its former range in California (Hayes and Jennings 1988, Shaffer et al. 2004). Range has been reduced by 70% (USFWS 1996, 2000).

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Factors contributing to local declines include wetland destruction and degradation/fragmentation, urbanization, residential development, reservoir construction, stream channelization, livestock grazing of riparian vegetation, off-road vehicle activity, drought, overharvesting, and exotic fishes (bass, mosquitofish) and possibly bullfrogs (Kiesecker and Blaustein 1988, 1998; USFWS 1994, 1996, 2000; Adams 1999, 2000; Lawler et al. 1999; Cook and Jennings 2001; Kiesecker, Blaustein and Miller 2001a; Cook 2002). Conversion of habitat to more permanent ponds is an important threat (as this allows breeding waters to be invaded by non-native predators). Habitat characteristics and good leaping ability may render Rana aurora/draytonii less vulnerable to bullfrog predation than is Rana pretiosa (Pearl et al. 2004). McAllister and Leonard (in Jones et al. 2005) noted that in many areas red-legged frogs coexist with bullfrogs.

Declines in the red-legged frog complex (including Rana draytonii) also have been attributed to global warming, UV-B radiation (Belden and Blaustein 2002), airborne contaminants (pesticide drift), and disease (see Davidson et al. 2001). Davidson et al. (2002) found support for the negative impact of wind-borne agrochemicals and weaker evidence for the widespread impact of habitat destruction and UV-B radiation; evidence did not support the hypothesis that declines have been caused by climate change.

This species has been extirpated from 99% of its Sierra Nevada range and is believed to be extinct in the Central Valley. Breeding populations remain along the coast, from San Mateo County to San Luis Obispo County. In 1996, it was declared a threatened species and over 4 million acres of habitat were designated as critical. However, in 2006 developers sued and 90% of that habitat designation was lost.

Now that has been partially remedied, thanks to legal action by the Center for Biological Diversity. As of March 16, 2010, the U. S. Fish and Wildlife Service has designated 1.6 million acres of habitat as critical, and the agency has acknowledged that the earlier reduction was flawed because of political interference from the Bush Administration.

Management Requirements: A final recovery plan is available (USFWS, Sacramento, California; telephone 916-414-6600; http://www.r1.fws.gov/ecoservices/endangered/recovery/default.htm).

Comments: Heavily exploited for human food in the late 1800s and early 1900s.

Comments: Significant morphological and behavioral differences between Rana draytonii and R. aurora suggest that they represent two species in secondary contact (Hayes and Krempels 1986, cited by USFWS 1994). Shaffer et al. (2004) presented genetic evidence supporting the recognition of Rana aurora and R. draytonii as distinct species.