Rana aurora

Baird and Girard, 1852

Northern Red-legged Frog

G4Apparently Secure Found in 75 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
Least concernIUCN
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.100633
Element CodeAAABH01021
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAmphibia
OrderAnura
FamilyRanidae
GenusRana
Synonyms
Rana aurora auroraBaird and Girard, 1852
Other Common Names
Grenouille à pattes rouges (FR) northern red-legged frog (EN)
Concept Reference
Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.
Taxonomic Comments
Genetic evidence supporting the recognition of Rana aurora and R. draytonii as distinct species is presented by Hayes and Miyamoto (1984), Shaffer et al. (2004), Conlon et al. (2006), and Pauly et al. (2008).

MtDNA data suggest that R. aurora, R. cascadae, and R. muscosa form a clade within the R. boylii species group (Macey et al. 2001).
Conservation Status
Rank MethodExpertise without calculation
Review Date2015-05-19
Change Date1996-11-01
Edition Date2008-06-26
Edition AuthorsHammerson, G.
Threat ImpactMedium
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
Large range in western North America; substantial declines in some areas; still widespread, common, and apparently secure in many areas; warrants rangewide monitoring.
Range Extent Comments
Range extends from southwestern British Columbia, including Vancouver Island in Canada, south along the coast of the United States (primarily west of Cascade-Sierran crest), to northwestern California (Shaffer et al. 2004). The species has been introduced and is well established and widely distributed on Graham Island, Queen Charlotte Islands (Haida Gwaii), British Columbia; it is unclear whether the species is native there or introduced many years ago (Ovaska et al. 2002). Rana aurora also is introduced and established on Chichagof Island, Alaska; the source of the frogs was Oregon (Hodge 2004).
Occurrences Comments
This species is represented by a large number of occurrences.
Threat Impact 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 1998; USFWS 1994, 1996, 2000; Adams 1999, 2000; Lawler et al. 1999; Cook and Jennings 2001; Kiesecker, Blaustein and Miller 2001a; Cook 2002). An important threat is the loss of wetlands in the Willamette Valley (Oregon) and Puget Lowlands (Washington), but populations remain in some urbanized areas (see Pearl, in Lannoo 2005). 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 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.
Ecology & Habitat

Description

Dorsum brown, gray, olive, or reddish, with irregular dark spotting or blotching; usually has a dark mask above the whitish jaw stripe; adults usually red on lower abdomen and underside of legs; usually coarse blackish, red, and yellow mottling in groin; relatively long legs (heel reaches at least to nostril when extended leg is pulled forward; eyes face outward, well covered by lids when viewed from above; prominent dorsolateral folds; snout-vent length usually 4-13 cm; young may have yellow instead of red on underside of legs and in groin; adult males have enlarged forelimbs and thumb base and more extensive webbing (Stebbins 1985).

Diagnostic Characteristics

Differs from R. PRETIOSA in having a mottled groin, eyes that are not turned upward, and the light jaw stripe ending before the shoulder rather than usually reaching the shoulder. Differs from R. CASCADAE in having less well-defined black spots on the dorsum, usually red rather than yellow on the lower abdomen and underside of the limbs, a more mottled groin, and generally smoother skin. Differs from R. BOYLII in having usually red rather than yellow on the underside of the limbs, a dark mask, prominent rather than indistinct dorsolateral folds, and smooth rather than granular eyedrums. (Stebbins 1985).

Habitat

Habitat includes the vicinity of permanent waters of stream pools, marshes, ponds, and other quiet bodies of water. This frog regularly occurs in damp woods and meadows some distance from water, especially during wet weather. Individuals (especially juveniles) seasonally can be found in and near ephemeral pools. Estivation sites include small mammal burrows and moist leaf litter in dense riparian vegetation up to at least 26 meters from water (Rathbun et al. 1993, cited by USFWS 1994). Desiccation cracks in dry pond bottoms may be used as refuges (Alvarez, 2004, Herpetol. Rev. 35:162-163). Breeding sites most often are in permanent water; eggs are attached to stiff submerged stems at the surface of the water.

Reproduction

Breeding time varies geographically; breeds March-July in the north. Breeding period lasts about 1-2 weeks. Eggs hatch in 5-7 weeks in western Oregon. Larvae metamorphose in about 11-20 weeks, but sometimes may overwinter. Larvae in British Columbia metamorphosed in 11-14 weeks.
Terrestrial Habitats
Forest/WoodlandForest - MixedGrassland/herbaceous
Palustrine Habitats
HERBACEOUS WETLANDRiparian
Other Nations (2)
United StatesN4
ProvinceRankNative
WashingtonS4Yes
CaliforniaS3Yes
AlaskaSNANo
OregonS3Yes
CanadaN3
ProvinceRankNative
British ColumbiaS3Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentHigh (continuing)
1.1 - Housing & urban areasHigh (continuing)
1.2 - Commercial & industrial areasHigh (continuing)
2 - Agriculture & aquacultureHigh (continuing)
2.3 - Livestock farming & ranchingHigh (continuing)
4 - Transportation & service corridorsHigh (continuing)
4.1 - Roads & railroadsHigh (continuing)
5 - Biological resource useInsignificant/negligible or past
5.1 - Hunting & collecting terrestrial animalsInsignificant/negligible or past
7 - Natural system modificationsHigh (continuing)
7.2 - Dams & water management/useHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesHigh (continuing)

Roadless Areas (75)
Alaska (5)
AreaForestAcres
ChichagofTongass National Forest555,858
Freshwater BayTongass National Forest44,933
Game CreekTongass National Forest54,469
Pavlof-East PointTongass National Forest5,399
Tenakee RidgeTongass National Forest20,527
California (14)
AreaForestAcres
Bell QuinbyShasta-Trinity National Forest11,556
Blue Creek Rare ISix Rivers National Forest12,134
Board CampSix Rivers National Forest4,527
Cow CreekShasta-Trinity National Forest22,627
Little French CShasta-Trinity National Forest11,529
North Fork SmithSix Rivers National Forest37,898
Orleans Mtn.Klamath National Forest49,090
Orleans Mtn. CSix Rivers National Forest15,589
PacksaddleSix Rivers National Forest3,862
Pilot CreekSix Rivers National Forest9,192
Siskiyou BSix Rivers National Forest18,871
Slide CreekSix Rivers National Forest11,458
SoliderSix Rivers National Forest14,918
South ForkShasta-Trinity National Forest16,786
Oregon (28)
AreaForestAcres
Bull Of The WoodsMt. Hood National Forest8,843
Bulldog RockUmpqua National Forest6,056
Calf - Copeland CreekUmpqua National Forest15,696
CornpatchWillamette National Forest7,346
Drift CreekSiuslaw National Forest6,333
EagleMt. Hood National Forest16,841
Echo MountainWillamette National Forest8,098
FairviewUmpqua National Forest7,417
French Pete (a)Willamette National Forest1,668
Gordon MeadowsWillamette National Forest9,463
Hebo 1aSiuslaw National Forest13,930
LarchMt. Hood National Forest12,961
Mclennon MountainWillamette National Forest8,085
Menagerie (rooster Rock)Willamette National Forest374
Middle SantiamWillamette National Forest7,316
Mosquito CreekWillamette National Forest335
Mt. Hood AdditionsMt. Hood National Forest13,061
Roaring RiverMt. Hood National Forest27,316
Salmon - HuckleberryMt. Hood National Forest17,570
Smith UmpquaSiuslaw National Forest7,622
TahkenitchSiuslaw National Forest5,799
TenmileSiuslaw National Forest10,818
Umpqua SpitSiuslaw National Forest2,090
Waldo - LakeWillamette National Forest2,993
Waldo - Salmon CreekWillamette National Forest3,195
Williams CreekUmpqua National Forest5,844
Wind CreekMt. Hood National Forest5,438
WoahinkSiuslaw National Forest5,309
Washington (28)
AreaForestAcres
BackboneGifford Pinchot National Forest1,201
Bear CreekGifford Pinchot National Forest7,980
Big Lava BedGifford Pinchot National Forest19,043
Boulder RiverMt Baker-Snoqualmie National Forest32,563
Canyon CreekWenatchee National Forest7,983
Dark DivideGifford Pinchot National Forest52,483
Eagle RockMt Baker-Snoqualmie National Forest34,064
Glacier Peak BMt Baker-Snoqualmie National Forest19,328
Glacier Peak IMt Baker-Snoqualmie National Forest15,175
Glacier Peak JMt Baker-Snoqualmie National Forest26,482
Glacier Peak KMt Baker-Snoqualmie National Forest47,269
Glacier Peak LMt Baker-Snoqualmie National Forest14,084
Heather LakeWenatchee National Forest10,628
Jefferson RidgeOlympic National Forest6,512
Jupiter RidgeOlympic National Forest10,148
LightningOlympic National Forest7,179
Mt. Baker MaMt Baker-Snoqualmie National Forest24,847
Mt. Baker Noisy - DiobsudMt Baker-Snoqualmie National Forest56,039
Mt. Baker NorthMt Baker-Snoqualmie National Forest16,873
Mt. BaldyOlympic National Forest3,557
Nason RidgeWenatchee National Forest19,329
Norse PeakWenatchee National Forest10,169
PompeyGifford Pinchot National Forest23,985
QuilceneOlympic National Forest18,656
Rugged RidgeOlympic National Forest4,358
South QuinaultOlympic National Forest11,081
StrawberryGifford Pinchot National Forest5,244
Upper SkokomishOlympic National Forest9,311
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