THE WINTER BIOENERGETICS OF A BEAVER POPULATION IN NORTHERN LATITUDES

1967 ◽  
Vol 45 (6) ◽  
pp. 1107-1118 ◽  
Author(s):  
N. S. Novakowski

The winter bioenergetics of a beaver population were studied in au area of Wood Buffalo National Park; which is located partly in Alberta and partly in the Northwest Territories. In these latitudes the beaver (Castor canadensis canadensis) are confined to subnivean existence for approximately 150 days each year. Although there is an unlimited supply of deciduous trees, which are cached by the colonies for this period, the caches were not sufficient for the energy requirements of the colonies, as calculated from the number and weight of animals in each colony. This indicates that energy deficits are a product of the winter behavior of the animals and that methods of energy conservation, such as reduced activity, periods of dormancy, huddling, insulation from ambient temperatures by lodge construction, and an increase in fur insulation and fat deposition provide the necessary mechanisms for survival. Based on a comparison of autumn and winter weights of beaver, the younger animals (kits and yearlings) increased their weight during the winter while the older animals, who presumably use fat reserves for survival, did not.

1978 ◽  
Vol 5 (2) ◽  
pp. 183 ◽  
Author(s):  
SR Morton

Reproduction in Sminthopsis crassicaudata was studied at three sites in south-eastern Australia: Werribee, Vic., Fowlers Gap Station, N.S.W., and Willandra National Park, N.S.W. At Werribee, the breeding season covered the period July-February. Individual females attempted to raise two litters during this season; there was no significant difference between the numbers of young weaned from first and second litters. Some females bred in two seasons, but it is unlikely that any males did so. At Fowlers Gap Station, breeding occurred in the same months as at Werribee, but there was variation between years in the onset of reproduction. At Willandra National Park, breeding occurred in the period June-December. There was no evidence of unseasonal, opportunistic breeding at either of these sites. As judged by pit-trapping, populations of invertebrate animals peaked in summer at Fowlers Gap Station, and probably at Werribee. Changes in weight and fat reserves also suggest that autumn and winter were periods of depressed food supply. The adaptive significance of the double-litter system and polyoestry is discussed. It is concluded that the overall biology of S. crassicaudata reflects adaptation to a fluctuating food supply. * Part II, Aust. Wildl. Res., 1978, 5, 163–82.


Author(s):  
Mark Boyce ◽  
Evelyn Merrill ◽  
Ronald Marrs

Summer range is not thought to be limiting to elk because abundant, high quality forage is available whereas a shortage of forage usually exists on elk winter ranges. Nevertheless, summer nutrition and fat reserves acquired on summer ranges influence growth, survival and reproduction of ungulates (Klein 1965, Verme 1963, 1965, Julander et al. 1961). The enormous area of summer range for the Northern Yellowstone elk herd renders detailed field surveys impractical. This study was initiated to evaluate the feasibility of using LANDSAT satellite imagery to (1) characterize vegetation communities on summer range from LANDSAT multispectral scanner (MSS) data and digitized vegetation maps of Yellowstone National Park, (2) predict plant production within grassland types and (3) correlate elk population characteristics with fluctuations in plant production and weather.


1964 ◽  
Vol 44 (3) ◽  
pp. 292-303 ◽  
Author(s):  
S. Pawluk ◽  
J. D. Lindsay

Exploratory surveys of the Wood Buffalo National Park in Northern Alberta revealed the presence of vast tracts of brunisolic soils. These soils are of common occurrence in the low plains area adjacent to Lake Clare.The brunisolic soils included in this study belong to the Brown Forest, Brown Wooded, and Acid Brown Wooded Great Soil Groups. All profiles were characterized with respect to their physical, chemical, and mineralogical properties. Special attention was directed to the Bf horizons where magnetic, amorphous (to X-ray) humus–iron micropellets were identified with the use of an electron microscope. The release of iron oxide from the weathering of iron-rich chlorites was also evident and is suggested as a mechanism by which the accretion of iron oxide to a pellet form could be explained. The possible genesis of these micropellets is fully discussed.


1991 ◽  
Vol 39 (6) ◽  
pp. 643 ◽  
Author(s):  
A Lill

The role of behavioural adjustments in meeting increased daily energy requirements in winter was investigated in rifleman, Acanthisitta chloris, inhabiting lowland forest in South I., New Zealand, by comparing their population density, time-activity budget and foraging behaviour in autumn and winter. Rifleman foraged for 83% of daytime in both seasons. The combined effects on the birds' winter energy budget of increased thermoregulation costs and the shorter daylength for foraging were at least partly offset by an estimated 23-29% decrease in the amount of energy expended daily on activity and a 78% increment in prey caught per day. The reduced energy expenditure on activity resulted from rifleman spending less time on expensive flying and more time roosting. The increase in prey capture rate may have stemmed from a 35% seasonal reduction in the birds' population density and reduced prey mobility at lower ambient temperatures. Marked sexual size dimorphism was not reflected in gender differences in activity budgeting or prey capture rate, but the sexes differed in their relative use of foraging substrates. Rifleman showed few seasonal changes in daily activity rhythm or microhabitat use. The behavioural energetic overwintering tactics of rifleman are compared with those of other Australasian and north temperate zone land-birds.


1993 ◽  
Vol 20 (5) ◽  
pp. 559 ◽  
Author(s):  
G Saunders

The demography of a sub-alpine population of feral pigs was examined at Kosciusko National Park in south-eastern New South Wales. Reproductive data and age structures indicated a seasonal pattern of breeding, most births occurring in summer and autumn. It is proposed that a decreasing availability of high protein food in the autumn and winter months caused reduced rates of conception. Sows produced 0.84 litters per year with postnatal mortality as high as 85%. The population appeared relatively stable at a density of 1.6 pigs kg-2. Hunting, although illegal in a national park, removed 4.4-15.4% of pigs each year. The overall health and body condition of pigs was good, with no evidence of heavy parasitic burdens or disease. Age-specific body weight and body length in this study were greater than those reported for pigs in semi-arid wester New South Wales.


1980 ◽  
Vol 58 (7) ◽  
pp. 1341-1346 ◽  
Author(s):  
Les W. Gyug ◽  
John S. Millar

Fat content (FAT), lean dry weight (LDW), and caloric content (KCAL) were examined in a natural subarctic population of Peromyscus maniculatus. FAT was not significantly correlated with size (LDW) of the animal. FAT of adult males was negatively correlated with minimum ambient temperatures and was not correlated with reproductive condition. LDW of adult males did not vary in relation to season. FAT of prebreeding adult females was high and decreased in response to breeding, but LDW increased in response to breeding so that KCAL remained constant. KCAL was low in adult females only after the breeding season. Mice dying in live traps had significantly lower FAT than did any other group of adults indicating that wild mice do not normally deplete their fat reserves. KCAL of postweaning young increased with age due to an increase in LDW but not in FAT. We suggest that fat levels are intrinsically controlled in wild Peromyscus according to the probability of having to make extraordinary energy expenditures and are not simply subject to extrinsic controls through the balance of food availability and energy demands.


1995 ◽  
Vol 59 (1) ◽  
pp. 189
Author(s):  
L. David Mech ◽  
L. N. Carbyn ◽  
S. M. Oosenbrug ◽  
D. W. Anions

2005 ◽  
Vol 83 (9) ◽  
pp. 1195-1205 ◽  
Author(s):  
Mark Bradley ◽  
John Wilmshurst

Two hypotheses have been proposed to explain the decline of bison (Bison bison (L., 1758)) abundance in Wood Buffalo National Park (WBNP). The "disease–predation" hypothesis proposes that tuberculosis (Mycobacterium bovis (Karlson and Lessel 1970)) and brucellosis (Brucella abortus (Schmidt 1901)) reduce bison survival and reproduction, resulting in a low-density, predator-regulated equilibrium. The "habitat dispersion hypothesis" proposes that bison in one area of WBNP, the Peace–Athabasca Delta (Delta), have an increased risk of predation because they are concentrated in large meadows with high temporal and spatial predictability. We incorporate bison census data, calf and yearling segregation counts, reproductive rates, adult survival rates, and adult disease incidence in a stochastic population model to show that the historical decline of bison in WBNP would have occurred regardless of disease prevalence. Our model shows that survival of juveniles, the age class that is least susceptible to disease effects, was likely an important determinant of historical changes in population size. We also demonstrate that the population decline was most pronounced in the Delta and that juvenile survival was lower in the Delta, despite evidence that disease incidence was lower in the Delta than in the rest of WBNP. Lastly, the current population trend in WBNP is one of rapid increase, even in the presence of disease.


1996 ◽  
Vol 72 (5) ◽  
pp. 485-490 ◽  
Author(s):  
Kevin Timoney

Logging of the riparian old-growth white spruce forests of Wood Buffalo National Park took place from 1951 to 1991. Operations were conducted in the Peace River valley in the Big Island block (Timber Berth (TB) 408) and the Peace Delta block, and in the Athabasca River valley. Approximately 70% of the pre-logging old-growth riparian forests have been lost to logging, leaving a remnant of ~100 km2 in the park, of which ~30 km2 are found in TB408. A minimum of 100 km2 has been logged from TB408. Natural regeneration has failed on 93% of these lands (9300 ha). The logging agreement, which expired in 1981, was renewed in 1983, the same year in which Wood Buffalo National Park was declared a UNESCO World Heritage Site. The history of logging in Wood Buffalo National Park is characterized by government mismanagement and industrial malpractice. There was never legal authority to log in Wood Buffalo National Park, as it contravened the National Parks Act (1930). The need for restoration is discussed. Key words: boreal, forestry, management, Peace River, riparian, white spruce, Wood Buffalo National Park


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