Natal dispersal of juvenile arctic ground squirrels in the boreal forest

1999 ◽  
Vol 77 (7) ◽  
pp. 1048-1059 ◽  
Author(s):  
Andrea E Byrom ◽  
Charles J Krebs
Keyword(s):  
Population Density ◽  
Resource Competition ◽  
Yukon Territory ◽  
Ground Squirrels ◽  
Natal Dispersal ◽  
Risk Of Mortality ◽  
Mortality Cost ◽  
Arctic Ground Squirrels ◽  
Dispersal Distances ◽  
Juvenile Males

Natal dispersal is assumed to be costly because of the risk of mortality, yet rarely are movement patterns and survival of dispersers observed directly. We determined the fates and dispersal distances of 150 radio-collared juvenile arctic ground squirrels from 1993 to 1995 at Kluane, Yukon Territory, Canada (61°N, 138°W). We tested the hypothesis that dispersal has a high mortality cost, and we also attempted to distinguish among three hypotheses to explain natal dispersal: competition for mates, competition for resources, and inbreeding avoidance. Juveniles were radio-collared at emergence from the natal burrow on five 9-ha grids nested within larger (1 km2) experimental manipulations: two controls, a predator exclosure, a food-supplemented grid, and a predator exclosure + food grid. In all years and on all areas, dispersing juveniles were more likely to die than philopatric squirrels, and the risk of mortality increased with distance from the natal burrow for both sexes. Overall, survival of philopatric squirrels was 73%, whereas survival of dispersing squirrels ranged from a maximum of 40% to a minimum of 25%. Juvenile females were strongly philopatric independent of population density, except on the predator exclosure + food grid in 1995, where population density was extremely high and resources other than food were probably limiting. Resource competition may explain patterns of philopatry and dispersal in female arctic ground squirrels. Juvenile males moved farther from their natal site than females and more of them died. Males also had a strong tendency to disperse that was independent of food availability or population density, which suggests that male arctic ground squirrels ultimately may disperse to avoid either inbreeding with female relatives or intrasexual competition for mates.

Population density and presence of the mother are related to natal dispersal in male and female Antechinus stuartii

2005 ◽  
Vol 53 (2) ◽  
pp. 103 ◽  
Author(s):  
D. O. Fisher
Keyword(s):  
Population Density ◽  
Natal Dispersal ◽  
Factors Affecting ◽  
Juvenile Dispersal ◽  
Linear Habitat ◽  
Antechinus Stuartii ◽  
Mating Opportunities ◽  
Dispersal Distances ◽  
A Site ◽  
Juvenile Males

In common with most mammals, the frequency of natal dispersal in antechinuses is strongly male-biased. Inbreeding avoidance has been put forward as the most likely explanation, with juvenile dispersal being driven by the mother. Dispersal distances and factors affecting emigration and immigration of each sex have not previously been studied in antechinuses, because of the difficulty of following the fates of individual dispersers. I studied a dense population of brown antechinuses (Antechinus stuartii) of known parentage in linear habitat that could be comprehensively trapped, and determined the fate of 27 females and 14 males that survived to dispersal age. Juvenile males dispersed not only more frequently than females (71% v. 11%), but also much further (maximum known distance: 1230 m v. 270 m). Males dispersed further if they had been raised in an area of low population density, and were more likely to immigrate into an area with a higher density of females than the natal site. Death of the mother disrupted normal home-range establishment, resulting in frequent philopatry of sons and dispersal of some daughters. Some females emigrated after young were weaned, and this also prompted dispersal of daughters. There was no evidence that daughters with surviving, philopatric mothers were more likely to survive to breed. I conclude that male-biased dispersal appears to result not only from costs of inbreeding, but also partly by the benefits of finding a site with more mating opportunities.

scholarly journals Sex-Related Natal Dispersal of White Storks (Ciconia Ciconia) in Poland: How Far and Where to?

The Auk ◽  
2006 ◽  
Vol 123 (4) ◽  
pp. 1103-1109 ◽  
Author(s):  
Nikita Chernetsov ◽  
Wiesław Chromik ◽  
Pawel T. Dolata ◽  
Piotr Profus ◽  
Piotr Tryjanowski
Keyword(s):  
Regression Analysis ◽  
Population Density ◽  
Interannual Variation ◽  
Natal Dispersal ◽  
High Population Density ◽  
Ciconia Ciconia ◽  
Nesting Sites ◽  
White Storks ◽  
Population Indices ◽  
Dispersal Distances

Abstract Distance and direction of natal dispersal were studied in a Polish White Stork (Ciconia ciconia) population on the basis of 25 years of banding and resighting data. Multiple regression analysis showed a significant sex-linked bias (females settled farther from the natal sites than males) and effect of banding year, in that dispersal distances were decreasing toward the end of the study period. Population indices in the hatching year and the presumed recruitment year did not help to explain the variance. The birds showed a trend toward settling southeast of the natal site, but this was significant only in individuals that settled within 50 km of the natal site. We suggest that when returning from winter sites in the southeast, young White Storks settle before they reach their presumed migratory target in the vicinity of the natal site. This is only possible if, in spite of a relatively high population density, many breeding areas and potential nesting sites remain vacant. This might also explain our failure to find density dependence in the interannual variation of dispersal distances.

Effects of food and predators on the home-range sizes of Arctic ground squirrel (Spermophilus parryii)

1998 ◽  
Vol 76 (3) ◽  
pp. 592-596 ◽  
Author(s):  
Anne H Hubbs ◽  
Rudy Boonstra
Keyword(s):  
Home Range ◽  
Ground Squirrel ◽  
Large Scale ◽  
Yukon Territory ◽  
Ground Squirrels ◽  
Home Ranges ◽  
Spermophilus Parryii ◽  
Mammalian Predators ◽  
Core Areas ◽  
Arctic Ground Squirrels

We used radiotelemetry to study the effects of food addition and predator reduction on the home-range sizes of adult Arctic ground squirrels (Spermophilus parryii) on large-scale experimental grids in the boreal forest of the southwestern Yukon Territory. Home ranges were 2-7 times smaller on food-supplemented grids than on nonsupplemented grids, regardless of whether large mammalian predators were present. Similarly, core areas (where 50% of activities occur) were 8-11 times smaller on food-supplemented grids. Food availability rather than predator presence primarily determined the sizes of home ranges and core areas of Arctic ground squirrels.

A multidisciplinary study of a Late Pleistocene arctic ground squirrel (Urocitellus parryii) midden from Yukon, Canada

2017 ◽  
Vol 89 (1) ◽  
pp. 333-351 ◽  
Author(s):  
Bram W. Langeveld ◽  
Dick Mol ◽  
Grant D. Zazula ◽  
Barbara Gravendeel ◽  
Marcel Eurlings ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Vascular Plant ◽  
Yukon Territory ◽  
Ground Squirrels ◽  
Multidisciplinary Study ◽  
Urocitellus Parryii ◽  
Arctic Ground Squirrels ◽  
Future Work ◽  
Adna Analysis ◽  
Insight Into

AbstractMiddens (nests and caches) of Late Pleistocene arctic ground squirrels (Urocitellus parryii) that are preserved in the permafrost of Beringia archive valuable paleoecological data. Arctic ground squirrels selectively include the plant material placed in middens. To account for this selectivity bias, we used a multi-proxy approach that includes ancient DNA (aDNA) and macro- and microfossil analyses. Here, we provide insight into Pleistocene vegetation conditions using macrofossils, pollen, phytoliths and non-pollen palynomorphs, and aDNA collected from one such midden from the Yukon Territory (Canada), which was formed between 30,740 and 30,380 cal yr BP. aDNA confirmed the midden was constructed by U. parryii. We recovered 39 vascular plant and bryophyte genera and 68 fungal genera from the midden samples. Grass and other herbaceous families dominated vegetation assemblages according to all proxies. aDNA data yielded several records of vascular plants that are outside their current biogeographic range, while some of the recovered fungi yielded additional evidence for local occurrence of Picea trees during glacial conditions. We propose that future work on fossil middens should combine the study of macro- and microfossils with aDNA analysis to get the most out of these environmental archives.

Ichnological evidence of jökulhlaup deposit recolonization from the Touchet Beds, Mabton, WA, USA

2013 ◽  
Vol 79 (1) ◽  
pp. 37-48 ◽  
Author(s):  
James A. MacEachern ◽  
Michael C. Roberts
Keyword(s):  
Secondary Succession ◽  
Ground Squirrels ◽  
The Other ◽  
Natal Dispersal ◽  
Glacial Lake ◽  
Pocket Gophers ◽  
Field Evidence ◽  
Late Wisconsinan ◽  
Dispersal Distances ◽  
Mount St Helens

AbstractThe late Wisconsinan Touchet Beds section at Mabton, Washington reveals at least seven stacked jökulhlaup deposits, five showing evidence of post-flood recolonization by vertebrates. Tracemakers are attributed to voles or pocket mice (1–3 cm diameter burrows) and pocket gophers or ground squirrels (3–6 cm diameter burrows). The Mount St. Helens S tephra deposited between flood beds contains the invertebrate-generated burrows Naktodemasis and Macanopsis. Estimates of times between floods are based on natal dispersal distances of the likely vertebrate tracemakers (30–50 m median distances; 127–525 m maximum distances) from upland areas containing surviving populations to the Mabton area, a distance of about 7.9 km. Tetrapods would have required at least two to three decades to recolonize these flood beds, based on maximum dispersal distances. Invertebrate recolonization was limited by secondary succession and estimated at only a few years to a decade. These ichnological data support multiple floods from failure of the ice dam at glacial Lake Missoula, separated by hiatal surfaces on the order of decades in duration. Ichnological recolonization times are consistent with published estimates of refill times for glacial Lake Missoula, and complement the other field evidence that points to repeated, autogenically induced flood discharge.

scholarly journals Seasonal changes in glucocorticoid and testosterone concentrations in free-living arctic ground squirrels from the boreal forest of the Yukon

2001 ◽  
Vol 79 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Rudy Boonstra ◽  
Anne H Hubbs ◽  
Eileen A Lacey ◽  
Carolyn J McColl
Keyword(s):  
Binding Capacity ◽  
Ground Squirrels ◽  
Base Line ◽  
Adult Males ◽  
Free Living ◽  
Active Season ◽  
Spermophilus Parryii ◽  
Free Cortisol ◽  
Arctic Ground Squirrels ◽  
Juvenile Males

We examined how glucocorticoid and testosterone concentrations changed from spring to summer by livetrapping free-living populations of arctic ground squirrels (Spermophilus parryii). The primary glucocorticoid was found to be cortisol, with corticosterone below measurable concentrations in most individuals. Livetrapping elicited a strong stress response in both sexes: breeding males and females trapped in spring had free cortisol concentrations 4 and 34 times, respectively, those of base-line animals. The maximum corticosteroid-binding capacity (MCBC) was unaffected by trapping and was about 3 times higher in breeding females than in breeding males. Over the active season, MCBC values were lowest in all male classes (juveniles, nonreproductive adults, and reproductive adults), being less than half those in all female classes; pregnant females had values approximately twice those of juvenile females. However, free cortisol concentrations were similar in all female classes and in juvenile males and about half those in adult males. Livetrapping increased testosterone concentrations in males over those found in samples from base-line males, and testosterone concentrations did not affect MCBC values. Testosterone concentrations in livetrapped animals differed significantly among male classes, with nonreproductive males maintaining concentrations 64% of those in breeding males and 10 times those in juveniles.

Arctic ground squirrels of the mammoth-steppe: paleoecology of Late Pleistocene middens (∼24000–29450 14C yr BP), Yukon Territory, Canada

2007 ◽  
Vol 26 (7-8) ◽  
pp. 979-1003 ◽  
Author(s):  
Grant D. Zazula ◽  
Duane G. Froese ◽  
Scott A. Elias ◽  
Svetlana Kuzmina ◽  
Rolf W. Mathewes
Keyword(s):  
Late Pleistocene ◽  
Yukon Territory ◽  
Ground Squirrels ◽  
Arctic Ground Squirrels

scholarly journals Habitat selection by arctic ground squirrels (Spermophilus parryii)

2010 ◽  
Vol 91 (5) ◽  
pp. 1251-1260 ◽  
Author(s):  
Oliver E. Barker ◽  
Andrew E. Derocher
Keyword(s):  
Habitat Selection ◽  
Ground Squirrels ◽  
Spermophilus Parryii ◽  
Arctic Ground Squirrels
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