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Home/Species/ Mt. Graham Red Squirrel

Tamiasciurus fremonti grahamensis

(J.A. Allen, 1894)

Mt. Graham Red Squirrel

T1T1 (GNRT1) Found in 1 roadless area NatureServe Explorer →
T1T1Global Rank
Critically endangeredIUCN
Very highThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.101915
Element CodeAMAFB08011
Record TypeSPECIES
ClassificationSubspecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNCritically endangered
Endemicendemic to a single state or province
KingdomAnimalia
PhylumCraniata
ClassMammalia
OrderRodentia
FamilySciuridae
GenusTamiasciurus
Synonyms
Tamiasciurus hudsonicus grahamensis(J.A. Allen, 1894)
Other Common Names
Mount Graham red squirrel (EN)
Concept Reference
Hall, E. R. 1981a. The Mammals of North America, second edition. Vols. I & II. John Wiley & Sons, New York, New York. 1181 pp.
Taxonomic Comments
This federally endangered red squirrel is one of the southernmost populations of the North American red squirrel species complex (Hope et al. 2016). It is now included in Tamiasciurus fremonti.
Conservation Status
Rank MethodLegacy Rank calculation - Biotics v1
Review Date2019-08-06
Change Date1996-03-04
Edition Date2019-08-06
Edition AuthorsTonn, S. (AZGFD)
Threat ImpactVery high
Range Extent<100-250 square km (less than about 40-100 square miles)
Number of Occurrences1 - 5
Rank Reasons
Small range in the Pinaleno Mountains, southeastern Arizona; population size (150-400) varies with cone crop; construction of a large astrophysical observatory complex has been a controversial threat.
Range Extent Comments
This subspecies is endemic to the Pinaleno Mountains, Graham County, southeastern Arizona. Current range is entirely within the Safford Ranger District of the Coronado National Forest Elevational range is about 2,375-3,265 meters.
Occurrences Comments
This only known population occurs within the Coronado National Forest, Pinaleno Mountains, Arizona.
Threat Impact Comments
Destructive, catastrophic wildfire, driven by climate change and insect damage, is currently the primary threat to habitat. Other threats include human disturbance factors; possible construction of additional facilities, associated roads, or other sites; Swift Trail being paved farther into the forest (likely increasing accessibility to increased numbers of low-clearance vehicles that did not travel the unpaved portion previously, raising the speed at which all vehicles travel the road, and increasing the chances of road-kill mortality); increasing numbers of mountain visitors (increases in vehicles, people, and ignition sources); and changes in squirrel food source availability and amounts (natural cone crop fluctuations, drying out of the forest, and possible competition with Abert's squirrels for food and/or shelter). If the climate becomes even warmer and drier, as predicted, this species and its high elevation, moist, cool forests may disappear entirely. [Source: USFWS 2008]
Ecology & Habitat

Habitat

Habitat includes spruce-fir and mixed conifer forests. See Anderson and Shafer (1991) for an account of the Holocene biogeography of the spruce-fir forests of southeastern Arizona (on Mt. Graham these forests have been present for at least 8000 years). Prefers to nest in tree cavities, but will also construct leaf nests and even use ground burrows.

Ecology

Density estimated at about 1 per 3.2 ha (USFWS 1987).
Terrestrial Habitats
Forest - Conifer
Other Nations (1)
United StatesN1
ProvinceRankNative
ArizonaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
4 - Transportation & service corridorsSmall (1-10%)Slight or 1-10% pop. declineLow (long-term)
4.1 - Roads & railroadsSmall (1-10%)Slight or 1-10% pop. declineLow (long-term)
7 - Natural system modificationsPervasive - restrictedExtreme - moderateModerate - low
7.1 - Fire & fire suppressionPervasive - restrictedExtreme - moderateModerate - low
8 - Invasive & other problematic species, genes & diseasesSmall (1-10%)Slight or 1-10% pop. declineLow (long-term)
8.1 - Invasive non-native/alien species/diseasesSmall (1-10%)Slight or 1-10% pop. declineLow (long-term)
11 - Climate change & severe weatherPervasive (71-100%)Extreme - seriousModerate - low
11.1 - Habitat shifting & alterationPervasive (71-100%)Extreme - seriousModerate - low
11.2 - DroughtsPervasive (71-100%)Extreme - seriousModerate - low

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Roadless Areas (1)
Arizona (1)
AreaForestAcres
PinalenoCoronado National Forest130,920
References (11)
  1. Anderson, R. S., and D. S. Shafer. 1991. Holocene biogeography of spruce-fir forests in southeastern Arizona--implications for the endangered Mt. Graham red squirrel. Madrono 38:287-295.
  2. Fitzpatrick, L. A., et al. 1993. Mount Graham red squirrel, TAMIASCIURUS HUDSONICUS GRAHAMENSIS, recovery plan. U.S. Fish and Wildlife Service. 182 pp.
  3. Hall, E. R. 1981a. The Mammals of North America, second edition. Vols. I &amp; II. John Wiley &amp; Sons, New York, New York. 1181 pp.
  4. Hirt, P. 1990. Endangered Arizona ecosystem threatened by telescope development: the Mount Graham red squirrel controversy. Endangered Species Update 7(6):1-5.
  5. Hope, A. G., J. L. Malaney, K. C. Bell, F. Salazar-Miralles, A. S. Chavez, B. R. Barber, and J. A. Cook. 2016. Revision of widespread red squirrels (genus: <i>Tamiasciurus</i>) highlights the complexity of speciation within North American forests. Molecular Phylogenetics and Evolution 100:170-182.
  6. Matthews, J.R. and C.J. Moseley (eds.). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index. Volume 2. Birds, Reptiles, Amphibians, Fishes, Mussels, Crustaceans, Snails, Insects, and Arachnids. xiii + pp. 561-1180. Beacham Publications, Inc., Washington, D.C.
  7. U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and threatened species recovery program: report to Congress. 406 pp.
  8. U.S. Fish and Wildlife Service (USFWS). 2008. Mount Graham red squirrel (<i>Tamiasciurus hudsonicus grahamensis</i>) 5-year review: summary and evaluation. U.S. Fish and Widlife Service, Arizona Ecological Services Field Office, Phoenix, Arizona.
  9. U.S. Fish and Wildlife Service (USFWS). 2019. Endangered and Threatened Wildlife and Plants; 90-Day Findings for Three Species. Federal Register 84(173):46927-46931.
  10. U.S. Fish and Wildlife Service (USFWS). 2021. Endangered and Threatened Wildlife and Plants; Technical Corrections for 18 Southwestern United States Species Found in Arizona, New Mexico, and Texas. Federal Register 86(225):67352-67360.
  11. U.S. Fish and Wildlife Service (USFWS). 3 June 1987. Determination of endangered status for the Mount Graham red squirrel. Federal Register 52:20994-20999.