Body mass variation in semidomesticated reindeer

1994 ◽  
Vol 72 (4) ◽  
pp. 681-688 ◽  
Author(s):  
T. Helle ◽  
I. Kojola
Keyword(s):  
Body Mass ◽  
Snow Depth ◽  
Detrimental Effect ◽  
Sampling Period ◽  
Late Winter ◽  
Supplemental Feeding ◽  
Mass Variation ◽  
Finnish Lapland ◽  
Coefficients Of Variation ◽  
Insect Harassment

The between-years and within-year variation in mass of semidomesticated reindeer calves and females was studied in four herds in Finnish Lapland. Mass data covered 11–23 years. In two of the herds the intensity of supplemental feeding in mid and late winter increased throughout the sampling period, whilst in two other herds the amount of food available per capita fell drastically as a result of increased density (about 1–4 individuals/km2). Calf mass increased in both supplementally fed herds and female mass in one of them. In herds on natural ranges female mass was density dependent. Both calf mass (three herds) and female mass (one herd) correlated negatively with the number of warm days in midsummer, most likely because of severe insect harassment. The sum of snow depth during the two or three preceding winters influenced body mass inversely in one herd and positively in another herd, where snow depth probably increased the availability of arboreal lichens. The detrimental effect of warm midsummers disappeared with intensification of supplemental feeding and the resultant improvement of female condition in winter. Within-year coefficients of variation (CV) correlated negatively with mean mass for calves in all four herds and for females in one herd. For calves (two herds) and for females (one herd) CV correlated positively with the number of warm days in midsummer. We suggest that late-born calves, and females who lost body reserves in winter, were most sensitive to insect harassment.

Effect of Daily Body Mass Variation on the Foraging Behaviour of Tit Species (Parus spp.)

Ethology ◽  
2003 ◽  
Vol 109 (12) ◽  
pp. 971-979 ◽  
Author(s):  
Marta Barluenga ◽  
Andrés Barbosa ◽  
Eulalia Moreno
Keyword(s):  
Body Mass ◽  
Foraging Behaviour ◽  
Mass Variation

Moose selection of canopy cover types related to operative temperature, forage, and snow depth

1991 ◽  
Vol 69 (12) ◽  
pp. 3071-3077 ◽  
Author(s):  
Francis E. Schwab ◽  
Michael D. Pitt
Keyword(s):  
Habitat Selection ◽  
Snow Depth ◽  
Canopy Cover ◽  
Late Winter ◽  
Early Winter ◽  
Thermal Limit ◽  
Operative Temperature ◽  
Metabolic Heat ◽  
High Forage ◽  
Selection Of

Simple linear and muliple regressions were used to determine the contribution of operative temperature (Te), forage, and snow depth to moose (Alces alces) selection of canopy cover types. The number of degree-hours for which Te exceeded the thermal limit at which panting is required to dissipate metabolic heat contributed significantly to selection during summer (1 June – 15 September) and late winter (16 January – 15 April). Forage explained canopy cover selection in early winter (16 November – 15 January) and contributed significantly to the best equation describing habitat selection during late winter. Snow depth contributed to habitat selection in early winter but was not related to habitat selection during late winter. During summer, moose generally selected against sites where Te exceeded 30 °C, the thermal limit requiring panting to dissipate metabolic heat. During late winter, moose also generally avoided canopy covers where Te commonly exceeded 8 °C, the temperature at which panting is required to dissipate heat. During early winter, moose apparently suffered minimal heat stress, as Te remained below 0 °C; consequently, moose selected canopy cover types that provided comparatively high forage availability.

FEEDING HABITS OF MULE DEER ON FALL, WINTER, AND SPRING RANGES NEAR KAMLOOPS, BRITISH COLUMBIA

1976 ◽  
Vol 56 (3) ◽  
pp. 531-542 ◽  
Author(s):  
W. WILLMS ◽  
A. McLEAN ◽  
R. RITCEY
Keyword(s):  
Plant Growth ◽  
Snow Depth ◽  
Growth Form ◽  
Feeding Habits ◽  
Mule Deer ◽  
Early Spring ◽  
Late Winter ◽  
Plant Growth Form ◽  
Early Fall ◽  
Tree Component

Diets of mule deer were studied in the Kamloops area from September to April. The forages of 67 rumen samples were sorted to grass, tree, shrub, and forb species and the percent oven-dry weights calculated for each. Polynomial regressions (to the third degree) were used to describe the use of each plant-growth form over time, as well as to determine the influence of snow depth on plant species consumption. Douglas fir formed most of the tree component of the diet of the deer. Consumption of this species was highest in December and January. Grass consumption was less than 10% until early spring when it increased to almost 100%. More forbs were consumed in fall than in winter, while shrubs were consumed more in early fall and late winter than in late fall. Species composition of each plant growth-form generally varied with season. Increasing snow depth altered the proportion of both small and large plants in the diet. As snow depth increased, fewer small plants but more large plants were consumed.

scholarly journals Snow-Creep Pressure on Masts

1989 ◽  
Vol 13 ◽  
pp. 154-158 ◽  
Author(s):  
Jan Otto Larsen ◽  
Jens Laugesen ◽  
Krister Kristensen
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Ground Level ◽  
Close Correlation ◽  
Late Winter ◽  
Pressure Measurements ◽  
Snow Pack ◽  
Snow Layer ◽  
Western Norway ◽  
Snow Pressure

Snow-pressure measurements have been carried out on two masts at the NGI avalanche station in Grasdalen, western Norway. These two tubular masts have diameters of 0.22 and 0.42 m, respectively, and are situated on a 25° slope with a deep snow cover. The most important conclusions are that within a homogeneous snow-pack there is a close correlation between snow-creep pressure and the product of acceleration due to gravity, g, density, ρ, and snow depth, H, that the highest pressures are recorded in late winter when the snow-pack is at the 0°C isothermal, and finally that a weak 0° C isothermal snow layer at ground level appears to increase snow pressure.

Gonadal and photoperiodic control of seasonal body weight changes in male voles

1984 ◽  
Vol 247 (1) ◽  
pp. R84-R88 ◽  
Author(s):  
J. Dark ◽  
I. Zucker
Keyword(s):  
Body Weight ◽  
Body Mass ◽  
Late Summer ◽  
Short Photoperiod ◽  
Late Winter ◽  
Weight Changes ◽  
Short Day ◽  
Long Day ◽  
Principal Factors ◽  
Gonadal Recrudescence

After 15 wk in a short photoperiod (10 h of light/day), adult male voles weighed 25% less and consumed 33% less food than did voles in a long photoperiod (14 h light/day). Neither body weight nor food intake differed among long- and short-day castrated voles. After 19 wk, castrated long-day voles weighed less than did intact animals. Voles reduced their body weight during the first 15 wk in the short photoperiod and increased their body mass during the succeeding 15 wk. Body mass of short-day voles was positively correlated with combined testes weight. Voles in the short photoperiod collected less nesting material than did their long-day counterparts at week 31. Pelage characteristics at week 32 were not affected by castration or by photoperiod. We conclude that the decreased body mass of male voles during the late summer, fall, and early winter reflects a decrease in circulating levels of testicular hormones; gonadal recrudescence and increased circulating androgen levels are in part responsible for the subsequent seasonal increase in body weight. Part of the increased body mass in late winter in field populations or in laboratory voles after 15 wk in the short photoperiod is independent of the resumption of gonadal activity. Fluctuations in neural and endocrine processes, rather than availability of food, are the principal factors underlying seasonal changes in energy balance.

Moose body mass variation revisited: disentangling effects of environmental conditions and genetics

Oecologia ◽  
2013 ◽  
Vol 174 (2) ◽  
pp. 447-458 ◽  
Author(s):  
Ivar Herfindal ◽  
Hallvard Haanes ◽  
Erling J. Solberg ◽  
Knut H. Røed ◽  
Kjell Arild Høgda ◽  
...  
Keyword(s):  
Body Mass ◽  
Environmental Conditions ◽  
Mass Variation

scholarly journals Self-similarity in glacier surface characteristics

2003 ◽  
Vol 49 (167) ◽  
pp. 547-554 ◽  
Author(s):  
Neil S. Arnold ◽  
W. Gareth Rees
Keyword(s):  
Surface Roughness ◽  
Energy Balance ◽  
Spatial Variability ◽  
Snow Depth ◽  
Surface Albedo ◽  
Small Scale ◽  
Late Winter ◽  
Glacier Surface ◽  
Correlation Lengths ◽  
Aerodynamic Roughness

AbstractCatchment-wide information on glacier snow-cover depth, surface albedo and surface roughness is important input data for distributed models of glacier energy balance. In this study, we investigate the small-scale (mm to 100 m) spatial variability in these properties, with a view to better simulating this variability in such models. Data were collected on midre Lovénbreen, a 6 km2 valley glacier in northwest Svalbard. The spatial variability of all three properties was found to be self-similar over the range of scales under investigation. Snow depth and albedo exhibit a correlation length within which measurements were spatially autocorrelated. Late-winter and summer properties of snow depth differed, with smaller depths in summer due to melt, and shorter correlation lengths. Similar correlation lengths for snow depth and surface albedo may suggest that snow-depth variation is an important control on the small-scale spatial variability of glacier surface albedo. For surface roughness, the data highlight a possible problem in energy-balance studies which use microtopographic surveys to calculate aerodynamic roughness, in that the scale of the measurements made affects the calculated roughness value. This suggests that further investigations of the relationships between surface form and aerodynamic roughness of glacier surfaces are needed.

scholarly journals An intercomparison between AMSR-E snow-depth and satellite C- and Ku-band radar backscatter data for Antarctic sea ice

2011 ◽  
Vol 52 (57) ◽  
pp. 279-290 ◽  
Author(s):  
Stefan Kern ◽  
Burcu Ozsoy-Cicek ◽  
Sascha Willmes ◽  
Marcel Nicolaus ◽  
Christian Haas ◽  
...  
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Weddell Sea ◽  
Late Winter ◽  
First Year ◽  
Radar Backscatter ◽  
Antarctic Sea Ice ◽  
Ridged Ice ◽  
Ice Fraction ◽  
Ku Band

AbstractAdvanced Microwave Scanning Radiometer (AMSR-E) snow-depth data for Antarctic sea ice are compared with ship-based visual observations of snow depth, ice type and ridged-ice fraction, and with satellite C-band and Ku-band radar backscatter observations for two ship cruises into the Weddell Sea (ISPOL 2004–05,WWOS 2006) and one cruise into the Bellingshausen Sea (SIMBA 2007) during late winter/spring. Most (>75%) AMSR-E and ship-based snow-depth observations agree within 0.2 m during WWOS and SIMBA. Remaining observations indicate substantial underestimations of snow depths by AMSR-E data. These underestimations tend to increase with the ridged-ice fraction for WWOS and SIMBA. In areas with large snow depths, a combination of relatively stable low C-band radar backscatter and variable Ku-band radar backscatter is associated with undeformed first-year ice and may indicate snow metamorphism at this time of year during SIMBA. In areas with small snow depths, a combination of relatively stable low Ku-band radar backscatter, high C-band radar backscatter and low C-band radar backscatter standard deviations is associated with rough first-year ice during SIMBA. This information can help to better understand causes of the observed AMSR-E snow-depth bias during late-winter/spring conditions with decreasing average snow depth and to delineate areas where this bias occurs.

Bioelectrical impedance estimation of fat-free body mass in children and youth: a cross-validation study

1992 ◽  
Vol 72 (1) ◽  
pp. 366-373 ◽  
Author(s):  
L. B. Houtkooper ◽  
S. B. Going ◽  
T. G. Lohman ◽  
A. F. Roche ◽  
M. Van Loan
Keyword(s):  
Body Weight ◽  
Body Mass ◽  
Cross Validation ◽  
Bioelectrical Impedance ◽  
Children And Youth ◽  
Regression Equations ◽  
Prediction Equations ◽  
Coefficients Of Variation ◽  
Bone Content ◽  
Free Body

The purposes of this study were to develop and cross-validate the “best” prediction equations for estimating fat-free body mass (FFB) from bioelectrical impedance in children and youth. Predictor variables included height2/resistance (RI) and RI with anthropometric data. FFB was determined from body density (underwater weighing) and body water (deuterium dilution) (FFB-DW) and from age-corrected density equations, which account for variations in FFB water and bone content. Prediction equations were developed using multiple regression analyses in the validation sample (n = 94) and cross-validated in three other samples (n = 131). R2 and standard error of the estimate (SEE) values ranged from 0.80 to 0.95 and 1.3 to 3.7 kg, respectively. The four samples were then combined to develop a recommended equation for estimating FFB from three regression models. R2 and SEE values and coefficients of variation from these regression equations ranged from 0.91 to 0.95, 2.1 to 2.9 kg, and 5.1 to 7.0%, respectively. As a result of all cross-validation analyses, we recommend the equation FFB-DW = 0.61 RI + 0.25 body weight + 1.31, with a SEE of 2.1 kg and adjusted R2 of 0.95. This study demonstrated that RI with body weight can predict FFB with good accuracy in Whites 10–19 yr old.

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