Severe reduction in genetic variation in a montane isolate: the endangered Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis)

IT is not often that astronomers get sucked into bio-politics. But the 1980s saw the start of a bitter feud that still rumbles around today — at least among some of America’s conspiracy theorists. At its heart was a diminutive hero, a 200-g Mount Graham Red Squirrel Tamiasciurus hudsonicus grahamensis unique to the tree-covered Pinaleño Mountains, a small isolated mountain range in southern Arizona, of which Mt Graham is the highest peak. Thought to be extinct in the 1950s, this little survivor reappeared in small numbers on the 3 200 m mountain during the 1970s, and, in 1987, with a population of a couple of hundred, it was formally listed as endangered (U.S. Fish and Wildlife Service 1992; 2011).

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Excavation of Red Squirrel (Tamiasciurus hudsonicus) Middens by Bears (Ursus spp.) in Limber Pine (Pinus flexilis) Habitat in Banff National Park, Alberta

The Canadian Field-Naturalist ◽

10.22621/cfn.v130i4.1918 ◽

2017 ◽

Vol 130 (4) ◽

pp. 281 ◽

Cited By ~ 2

Author(s):

David Hamer

Keyword(s):

National Park ◽

Forest Cover ◽

Habitat Characteristics ◽

Tamiasciurus Hudsonicus ◽

Red Squirrel ◽

Limber Pine ◽

Banff National Park ◽

Pine Stands ◽

Study Sites ◽

Pinus Spp

Bears (Ursus spp.) in North America eat the seeds of several pines (Pinus spp.), including Limber Pine (P. flexilis E. James). Information on use of Limber Pine in Canada is limited to a report of three bear scats containing pine seeds found in Limber Pine stands of southwestern Alberta. After my preliminary fieldwork in Banff National Park revealed that bears were eating seeds of Limber Pine there, I conducted a field study in 2014–2015 to assess this use. Because bears typically obtain pine seeds from cone caches (middens) made by Red Squirrels (Tamiasciurus hudsonicus), I described the abundance, habitat characteristics, and use by bears of Red Squirrel middens in and adjacent to Limber Pine stands at six study sites. On Bow River escarpments, I found abundant Limber Pines (basal area 1–9 m2/ha) and middens (0.8 middens/ha, standard deviation [SD] 0.2). Of 24 middens, 13 (54%) had been excavated by bears, and three bear scats composed of pine seeds were found beside middens. Although Limber Pines occurred on steep, xeric, windswept slopes (mean 28°, SD 3), middens occurred on moderate slopes (mean 12°, SD 3) in escarpment gullies and at the toe of slopes in forests of other species, particularly Douglas-fir (Pseudotsuga menziesii). At the five other study sites, I found little or no use of Limber Pine seeds by bears, suggesting that Limber Pine habitat may be little used by bears unless the pines are interspersed with (non-Limber Pine) habitat with greater forest cover and less-steep slopes where squirrels establish middens. These observations provide managers with an additional piece of information regarding potential drivers of bear activity in the human-dominated landscape of Banff National Park’s lower Bow Valley.

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SEASONAL DAMAGE BY INSECTS AND SQUIRRELS TO FEMALE REPRODUCTIVE STRUCTURES OF BLACK SPRUCE, PICEA MARIANA (MILL.) B.S.P.

The Canadian Entomologist ◽

10.4039/ent1201113-12 ◽

1988 ◽

Vol 120 (12) ◽

pp. 1113-1121 ◽

Cited By ~ 15

Author(s):

Y.H. Prévost ◽

J.E. Laing ◽

V.F. Haavisto

Keyword(s):

Picea Mariana ◽

Black Spruce ◽

Choristoneura Fumiferana ◽

Tamiasciurus Hudsonicus ◽

Red Squirrel ◽

Red Squirrels ◽

Reproductive Structures ◽

Cone Axis ◽

Viable Seeds ◽

Cone Growth

AbstractThe seasonal damage to female reproductive structures (buds, flowers, and cones) of black spruce, Picea mariana (Mill.) B.S.P., was assessed during 1983 and 1984. Nineteen insects (five Orders) and the red squirrel, Tamiasciurus hudsonicus (Erxleben), were found feeding on these reproductive structures. Collectively, these organisms damaged 88.9 and 53.5% of the cones in 1983 and 1984, respectively. In the 2 years, Lepidoptera damaged 61.8% of the cones in 1983 and 44.4% of the cones in 1984. The spruce budworm, Choristoneura fumiferana (Clem.), and the spruce coneworm, Dioryctria reniculelloides Mut. and Mun., were the most important pests. Cones damaged by Lepidoptera could be classed into three categories: (a) severe, yielding no seeds; (b) moderate, yielding 22.3 seeds per cone; and (c) light, yielding 37.5 seeds per cone. Undamaged cones yielded on average 39.9 seeds per cone. Red squirrels removed 18.8% of the cones in 1983 and none in 1984. The spruce cone axis midge, Dasineura rachiphaga Tripp, and the spruce cone maggot, Lasiomma anthracinum (Czerny), caused minor damage in both years. Feeding by spruce cone axis midge did not reduce cone growth significantly or the number of viable seeds per cone, but feeding by the spruce cone maggot did. During both years new damage by insects to the female reproductive structures of the experimental trees was not observed after mid-July. In 1983 damage by red squirrels occurred from early to late September. In 1984 damage to cones on trees treated with dimethoate was 15.6% compared with 53.5% for untreated trees, without an increase in the number of aborted cones.

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Ontogénèse du comportement de l'Ecureuil roux (Tamiasciurus hudsonicus)

Canadian Journal of Zoology ◽

10.1139/z80-152 ◽

1980 ◽

Vol 58 (6) ◽

pp. 1090-1099 ◽

Cited By ~ 5

Author(s):

Jean Ferron

Keyword(s):

Social Interactions ◽

Detailed Analysis ◽

Early Life ◽

Neonatal Period ◽

Transition Period ◽

Physical Development ◽

Tamiasciurus Hudsonicus ◽

Behaviour Pattern ◽

Red Squirrel ◽

Behavioural Development

A detailed analysis of the behavioural development of the red squirrel (Tamiasciurus hudsonicus) from birth to weaning is presented. For each behaviour pattern, the earliest and latest ages of emergence in a series of 14 young (from three litters) were registered and a mean was calculated. A review of the principal events of physical development is given first. The ontogeny of behaviour is then considered under five headings: locomotion, alertness and exploration, feeding, comfort, and social interactions. In the discussion, a general analysis of the development of behaviour with regard to the different periods of ontogeny (neonatal period, transition period, and socialization period) and the two leading events of the early life of the red squirrel (emergence from the nest and weaning) is given. It appears that the young are equipped with a minimum of behaviour patterns during the period of nest confinement and that close to emergence, a series of new behaviours come into effect with the exception of locomotion, which evolves gradually and regularly during ontogeny.

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Genetic structure of the arboreal squirrels (Glaucomys sabrinus and Tamiasciurus hudsonicus) in the North American Black Hills

Canadian Journal of Zoology ◽

10.1139/z2012-087 ◽

2012 ◽

Vol 90 (9) ◽

pp. 1191-1200 ◽

Cited By ~ 1

Author(s):

A.M. Kiesow ◽

E.M. Monroe ◽

H.B. Britten

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Management Practices ◽

Allelic Diversity ◽

Black Hills ◽

Tamiasciurus Hudsonicus ◽

Glaucomys Sabrinus ◽

Red Squirrel ◽

Isolated Populations ◽

Red Squirrels

We selected two isolated mammalian populations, the Black Hills northern flying squirrel ( Glaucomys sabrinus (Shaw, 1801)) and red squirrel ( Tamiasciurus hudsonicus (Erxleben, 1777)), to elucidate their genetic structure. We trapped both squirrels from 2005 to 2007, in three regions of the Black Hills, differing in geology and vegetation, to collect ear samples for genetic analyses. Microsatellite loci (northern flying (9) and red squirrel (13)) were used to examine genetic structure. Data analyses estimated genetic variability, substructure, and gene flow. Northern flying and red squirrel populations have allelic diversity and observed heterozygosity similar to other isolated populations. Each species shows weak substructure from STRUCTURE and GENELAND analyses, suggesting squirrel movements may be inhibited by topography or unsuitable habitat. Recent gene flow estimates from BAYESASS indicate that both species experience some within population gene flow and red squirrels may be more structured than northern flying squirrels because of lower migration rates. Concordant patterns of genetic structure in northern flying and red squirrels indicate that other species’ movements in the Black Hills may be affected by topography and habitat. Because their habitat is isolated in the Black Hills, management practices and conservation measures are recommended to promote viability and survival of each species.

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Body temperature dynamics of the red squirrel (Tamiasciurus hudsonicus): adaptations for energy conservation

Canadian Journal of Zoology ◽

10.1139/z79-175 ◽

1979 ◽

Vol 57 (7) ◽

pp. 1349-1354 ◽

Cited By ~ 14

Author(s):

Ronald W. Pauls

Keyword(s):

Body Temperature ◽

Motor Activity ◽

Energy Conservation ◽

Outdoor Environment ◽

Tamiasciurus Hudsonicus ◽

Rapid Decline ◽

Red Squirrel ◽

Red Squirrels ◽

Air Temperatures ◽

Temperature Dynamics

Abdominal temperatures (Tb) of two captive female red squirrels (Tamiasciurus hudsonicus) in a natural outdoor environment were monitored by radiotelemetry at air temperatures (Ta) from −33 to 28 °C. Abdominal temperature ranged from 35.9 to 41.4 °C with values usually less than 39 °C when an animal was in the nest and greater than 39 °C when outside. An increase of Tb to about 39 °C usually occurred before an animal left the nest. In the nest Tb was positively correlated with Ta. Outside the nest there was a weak positive correlation at Ta less than 15 °C and a stronger negative correlation at higher Ta. During subnivean activity a rapid decline in Tb usually occurred. It is suggested that in the nest a low Tb is adaptive in that it results in energy conservation while a higher Tb is required outside the nest for rapid and coordinated motor activity.

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The Biology of the Red Squirrel, Tamiasciurus hudsonicus loquax (Bangs), in Central New York

Ecological Monographs ◽

10.2307/1948465 ◽

1954 ◽

Vol 24 (3) ◽

pp. 227-268 ◽

Cited By ~ 100

Author(s):

James N. Layne

Keyword(s):

New York ◽

Tamiasciurus Hudsonicus ◽

Red Squirrel ◽

Central New York

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Solitary play of the red squirrel (Tamiasciurus hudsonicus)

Canadian Journal of Zoology ◽

10.1139/z75-183 ◽

1975 ◽

Vol 53 (11) ◽

pp. 1495-1499 ◽

Cited By ~ 1

Author(s):

Jean Ferron

Keyword(s):

Relative Proportion ◽

Play Behavior ◽

Tamiasciurus Hudsonicus ◽

Red Squirrel ◽

Motor Patterns ◽

Play Fighting ◽

Social Species ◽

Solitary Play ◽

The Social ◽

Use Of An Object

A description of the different forms of solitary play behavior in the red squirrel (Tamiasciurus hudsonicus) is presented here. These play activities are subdivided into two main groups: non-directed and object-directed. In the first are included (a) tumbles on the ground; (b) leaps and feats of skill in trees; (c) body shaking while suspended by the feet, and (d) running. In the second the motor patterns can be (a) gnawing, eating and caching food; (b) rubbing against an object; (c) acrobatic use of an object; (d) play-fighting with objects, and (e) chasing and play-fighting with the tail. The comparison of the solitary play behavior of the red squirrel with that of some other sciurids shows that this behavior seems to be almost non-existent in the social species studied so far and is subject to variation with age at the intraspecific level. It is suggested that a certain relation exists between the degree of sociability and the relative proportion of solitary and social play activities.

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