A Winter Food Cache of Microtus pennsylvanicus

1980 ◽  
Vol 103 (2) ◽  
pp. 407 ◽  
Author(s):  
J. Edward Gates ◽  
Donna M. Gates
2017 ◽  
Vol 130 (4) ◽  
pp. 332 ◽  
Author(s):  
Thomas S Jung ◽  
Jay Frandsen ◽  
Danny C Gordon ◽  
David H Mossop

A consequence of rapid global warming has been the shrubification (increase in shrub abundance, cover, and biomass) of arctic and alpine tundra ecosystems. Shrubification is likely a key driver of predicted and observed changes in the biodiversity of the Arctic. The American Beaver (Castor canadensis) has a vast distributional range, covering most of north America below the tree line; however, it has not been recorded in tundra habitat of the Beaufort Coastal Plain of Yukon and Alaska. in 2015, we observed a beaver dam, lodge, and winter food cache on the Babbage River in Ivvavik National Park, Yukon, Canada. Local Inuvialuit hunters first observed beavers on two rivers immediately east of the Babbage River in 2008 and 2009. Together, these are the first observations of beavers on the Beaufort Coastal Plain and indicate initial attempts at colonization. Colonization of the Beaufort Coastal Plain by beavers may have been facilitated by shrubification of river valleys on the tundra of northern Yukon and adjacent Alaska, which is a consequence of rapid climate warming in the western Arctic.


1992 ◽  
Vol 29 (2) ◽  
pp. 371 ◽  
Author(s):  
J.-D. Bucyanayandi ◽  
J.-M. Bergeron ◽  
J. Soucie ◽  
D. W. Thomas ◽  
Y. Jean

1983 ◽  
Vol 61 (6) ◽  
pp. 1232-1241 ◽  
Author(s):  
Richard R. Snell ◽  
Kimberly M. Cunnison

Analyses of geographic variation in the skull of meadow voles (Microtus pennsylvanicus) indicate that phenetic distances among samples are not related to geographic distance: a minimum spanning tree based on average taxonomic distance superimposed on a map of 38 localities provides no particular phenetic clustering of those samples geographically proximate. A multiple regression of phenetic component one (skull size) onto orthogonally rotated climatic factors explains much less morphometric variation (25.6%) than a simple correlation with recorded extreme low temperature (38.9%). Multiple regression of phenetic principal component two (interorbital width) onto the same climatic factors explains minimally more morphological variation (42.1%) than a simple correlation with mean annual number of days with frost (41.7%). Microtus pennsylvanicus shows a pattern of size variation that is the reverse of Bergmann's rule: these voles are large where it is warm and small where it is cold. Since small size reduces total energy expenditure, we predict that during times of extreme low temperature (i) smaller voles will be less energetically stressed than larger voles and (ii) large size will be actively selected against.


1975 ◽  
Vol 53 (8) ◽  
pp. 1004-1011 ◽  
Author(s):  
Brian N. Turner ◽  
Michael R. Perrin ◽  
Stuart L. Iverson

Beginning in November 1973, numerous meadow voles (Microtus pennsylvanicus) moved onto a spruce forest grid occupied by red-backed voles (Clethrionomys gapperi). A resident meadow vole population resulted, the two species coexisting until April 1974, when most meadow voles disappeared from the grid during a relatively short period. Interspecific aggression levels, as determined from voles temporarily removed from the populations and tested in paired encounters in a laboratory arena, were low during the winter, but increased when males of both species entered reproductive condition in the spring. Microtus was generally dominant in early breeding period encounters, but this dominance declined concurrently with the meadow voles' disappearance from the forest. It is argued that meadow voles did not leave the forest to breed, or because the snow cover melted, since this species will live and reproduce in forest in the absence of Clethrionomys. The results are interpreted as support for an earlier hypothesis that competitive habitat exclusion varies seasonally with reproduction-related aggression. Thus, these species apparently may coexist in either of their preferred habitats when interspecific aggression is low (the nonbreeding season), but this relationship terminates when interspecific aggression levels increase with the resumption of breeding in the spring.


2013 ◽  
Vol 132 (6) ◽  
pp. 563-570 ◽  
Author(s):  
Yada Chutimanitsakun ◽  
Alfonso Cuesta-Marcos ◽  
Shiaoman Chao ◽  
Ann Corey ◽  
Tanya Filichkin ◽  
...  

1986 ◽  
Vol 43 (2) ◽  
pp. 211-223 ◽  
Author(s):  
I. A. Wright ◽  
A. J. F. Russel ◽  
E. A. Hunter

ABSTRACTTwo experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0·31, 0·58 and 0·79 (s.e. 0·027) kg/day (P < 0·001) during the 152-day winter in experiment 1 and 0·44, 0·69 and 0·84 (s.e. 0·029) kg/day (P < 0·001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1·10, 1·02, 0·87 and 1·35, 1·23 and 1·19 (s.e. 0·060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 0·01) and 0·86, 0·66, 0·51 and 1·26, 1·18 and 0·91 (s.e. 0090) kg/day in experiment 2 (P < 0·001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.


1962 ◽  
Vol 40 (6) ◽  
pp. 969-990 ◽  
Author(s):  
Reino S. Freeman

Taenia crassiceps was common in Vulpes fulva examined from southern Ontario. Metacestodes occurred naturally in Microtus pennsylvanicus, Marmota monax, Tamias striatus, and Ondatra zibethicus, and Peromyscus maniculatus, Tamiasciurus hudsonicus, and Sciurus carolinensis were infected experimentally; all rodents are new host records. Cysticerci developed into adults in dogs or foxes within 5 to 6 weeks; five coyote pups resisted infection. Development of the metacestode was followed mainly in white mice. Infections were most common subcutaneously, but also occurred in both body cavities. Mice approximately 4 weeks of age were most susceptible. Asexual reproduction occurred by exogenous, and rarely endogenous, budding from the abscolex pole beginning approximately 3 weeks after infection. Metacestodes in various stages of development were injected into mice subcutaneously, intrapleurally, but mainly intraperitoneally. Subsequent development and reproduction were similar to that following infection with eggs. Apparently all metacestodes are capable of budding. The initial rate of reproduction was higher subcutaneously and intrapleurally than intraperitoneally, but within approximately 100 days the rate became higher and continued higher intraperitoneally than elsewhere. Reproduction never reached a logarithmic rate. Metacestodes inoculated serially up to 21 times at 50-day intervals increased greatly in size and continued budding. Four other series were maintained by serial subinoculation at 50-day intervals through 23 generations without a significant change in the rate of reproduction.


1897 ◽  
Vol s8-XI (282) ◽  
pp. 405-405
Author(s):  
Arthur Mayall
Keyword(s):  

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