The ecophysiology of survival in juvenile red kangaroos Macropus rufus: greater demands and higher costs.

2004 ◽  
Vol 26 (2) ◽  
pp. 161 ◽  
Author(s):  
AJ Munn ◽  
TJ Dawson
Keyword(s):  
Body Mass ◽  
Arid Regions ◽  
Resting Metabolic Rate ◽  
High Quality ◽  
Energy Turnover ◽  
Growth And Survival ◽  
Risk Of Predation ◽  
Macropus Rufus ◽  
High Fibre ◽  
Lactating Females

Red kangaroos (Macropus rufus) are large (> 20 kg) herbivorous marsupials common to the arid and semi-arid regions of inland Australia. The population dynamics of M. rufus is tightly linked to environmental factors, which operate partly through the survival of juveniles. A crucial period is the young-at-foot (YAF) stage when juveniles have permanently left the mother?s pouch. YAF and weaned kangaroos have the highest drought-related mortalities of any cohort and show notable differences from adults in their basic physiology. YAF and weaned M. rufus, for example, had a resting metabolic rate (kJ kg-1 d-1) twice that of mature females and 1.5 times that expected for an adult marsupial of equivalent body mass (i.e., kJ kg-0.75 d-1). This greater energy turnover was largely explained by their metabolic demands for growth; juveniles required 70 - 95% of the digestible energy intake (kJ d-1) of mature, non-lactating females. Meeting these costs may not be a problem for juveniles when high-quality, low-fibre forage is available, but they were constrained when only hard-to-digest, high-fibre forage was available. YAF and weaned kangaroos, for example, were unable to sustain growth on forages of more than 40 ? 50% fibre, fibre levels characteristic of forages in arid regions during drought. Yet mature, non-lactating females were capable of maintaining body mass on similar forage. Additionally, juvenile M. rufus required relatively more water than adults for thermoregulation (by up to 2.5-fold), especially under hot conditions, and may need to drink more frequently than adults. Thus, juveniles appear constrained to remain close to water points, increasing their risk of predation and limiting their ability to find the high-quality forage needed for their growth and survival.

Metabolic rate in female European roe deer (Capreolus capreolus): incidence of reproduction

1997 ◽  
Vol 75 (5) ◽  
pp. 731-739 ◽  
Author(s):  
Christiane Mauget ◽  
Robert Mauget ◽  
Antoine Sempéré
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Roe Deer ◽  
Post Partum ◽  
Resting Metabolic Rate ◽  
Capreolus Capreolus ◽  
First Year ◽  
Lactating Females ◽  
Reproduction Costs ◽  
Ad Libitum Feeding

Indirect calorimetry measurements were made continuously over a 2-year period in 10 adult female roe deer (Capreolus capreolus) maintained in outdoor enclosures on ad libitum feeding. Results from adult nonpregnant does revealed no endogenous seasonal rhythm in resting metabolic rate (RMR), in contrast to most cervid species. Throughout the 2 years of our study, RMR (overall mean 4695 ± 65 kJ∙d−1) fluctuated in parallel with variations in body mass. The mass-specific RMR ranged from 221.2 ± 4.8 to 230.7 ± 4.0 kJ∙kg−1∙d−1 (466.0 ± 10.8 to 495.5 ± 9.7 kJ∙kg−0.75∙d−1). Results from pregnant females (five in the first year, four in the second) showed that their energy expenditure increased by 15% during the last 2 months of gestation, in step with the increase in body mass. A 27% increase in RMR was recorded in lactating females during the first month post partum. These results show that in a small-bodied cervid such as the roe deer, reproduction costs are no higher than in other wild herbivores.

scholarly journals Influence of body composition on physical activity validation studies using doubly labeled water

2004 ◽  
Vol 96 (4) ◽  
pp. 1357-1364 ◽  
Author(s):  
Louise C. Mâsse ◽  
Janet E. Fulton ◽  
Kathleen L. Watson ◽  
Matthew T. Mahar ◽  
Michael C. Meyers ◽  
...  
Keyword(s):  
Physical Activity ◽  
Body Composition ◽  
Energy Expenditure ◽  
Body Mass ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Doubly Labeled Water ◽  
Comparison Analysis ◽  
Methods Comparison ◽  
Statistical Procedures

This study investigated the influence of two approaches (mathematical transformation and statistical procedures), used to account for body composition [body mass or fat-free mass (FFM)], on associations between two measures of physical activity and energy expenditure determined by doubly labeled water (DLW). Complete data for these analyses were available for 136 African American (44.1%) and Hispanic (55.9%) women (mean age 50 ± 7.3 yr). Total energy expenditure (TEE) by DLW was measured over 14 days. Physical activity energy expenditure (PAEE) was computed as 0.90 × TEE - resting metabolic rate. During week 2, participants wore an accelerometer for 7 consecutive days and completed a 7-day diary. Pearson's product-moment correlations and three statistical procedures (multiple regressions, partial correlations, and allometric scaling) were used to assess the effect of body composition on associations. The methods-comparison analysis was used to study the effect of body composition on agreement. The statistical procedures demonstrated that associations improved when body composition was included in the model. The accelerometer explained a small but meaningful portion of the variance in TEE and PAEE after body mass was accounted for. The methods-comparison analysis confirmed that agreement with DLW was affected by the transformation. Agreement between the diary (transformed with body mass) and TEE reflected the association that exists between body mass and TEE. These results suggest that the accelerometer and diary accounted for a small portion of TEE and PAEE. Most of the variance in DLW-measured energy expenditure was explained by body mass or FFM.

Habitat Selection by Sex, Age and Reproductive Class in the Red Kangaroo, Macropus rufus, in Western New South Wales

1981 ◽  
Vol 8 (3) ◽  
pp. 465 ◽  
Author(s):  
CN Johnson ◽  
PG Bayliss
Keyword(s):  
Habitat Selection ◽  
National Park ◽  
Mating Systems ◽  
New South ◽  
New South Wales ◽  
Vegetation Types ◽  
Red Kangaroo ◽  
South Wales ◽  
Macropus Rufus ◽  
Lactating Females

The kangaroo populations of Kinchega National Park respond differently to shifts in pasture productivity, red kangaroos Macropus rufus being mobile and unevenly distributed with respect to soil and vegetation types, by comparison with the more evenly dispersed western grey kangaroos M. fuliginosus and the sedentary and localized euros M, robustus erubescens. Red kangaroo population classes tend to be differentially distributed, so that large males and heavily lactating females predominate on the seasonally preferred pastures, while other classes tend to predominate elsewhere. This finding has several implications for the management of red kangaroos and for our understanding of their resource ecology and mating systems.

scholarly journals Gosling Growth and Survival in Relation to Brood Movements in Greater Snow Geese (Chen Caerulescens Atlantica)

The Auk ◽  
2006 ◽  
Vol 123 (4) ◽  
pp. 1077-1089 ◽  
Author(s):  
Julien Mainguy ◽  
Gilles Gauthier ◽  
Jean-François Giroux ◽  
Joël Bêty
Keyword(s):  
Selective Advantage ◽  
Nest Site Selection ◽  
High Quality ◽  
Growth And Survival ◽  
Chen Caerulescens ◽  
Brood Rearing ◽  
Snow Geese ◽  
Movement Distance ◽  
Chen Caerulescens Atlantica ◽  
Precocial Birds

Abstract Post-hatch brood movements to high-quality foraging sites are common in precocial birds but may entail costs for young. We assessed effects of overland movements of broods between the nesting and rearing areas in Greater Snow Geese (Chen caerulescens atlantica) breeding on Bylot Island, Nunavut, Canada, to determine whether these movements affected gosling survival and growth. We monitored 51 radiomarked females over five years to quantify movement distance, movement duration, and gosling survival. Gosling growth was compared over four years using a sample of web-tagged broods recaptured shortly before fledging among adults that (1) nested and reared their young in a dense colony, (2) left the colony and moved ≈30 km to reach the main brood-rearing area, or (3) nested and reared their young in the main brood-rearing area. Brood movements by radio-marked birds were highly variable (2.6-52.5 km, depending on rearing areas used) and fairly rapid (≤6 days after hatch for 72% of the females). Gosling survival was not related to distance moved between nesting and brood-rearing areas. However, gosling growth was influenced by areas used and whether or not they had to move to reach their brood-rearing area. Geese nesting at the main brood-rearing area generally reared heavier and larger goslings than those that moved ≈30 km from the main nesting colony to rear their brood at the main brood-rearing area. On the other hand, goslings leaving the nesting colony after hatch were heavier and larger than those that stayed there throughout brood rearing in one of two years. Although brood movements allow goslings access to high-quality habitats, they entail some costs. Thus, minimizing such movements through nest-site selection should provide a selective advantage by allowing goslings to maximize their growth. Croissance et Survie des Oisons en Relation avec les Déplacements des Familles chez Chen caerulescens atlantica

scholarly journals Does risk of predation influence population dynamics? Evidence from cyclic decline of snowshoe hares

1995 ◽  
Vol 22 (1) ◽  
pp. 115 ◽  
Author(s):  
D. S. Hik
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Female Body ◽  
Population Decline ◽  
Control Area ◽  
High Rate ◽  
Food Treatment ◽  
Snowshoe Hares ◽  
Risk Of Predation ◽  
Female Body Mass

Like most heavily preyed-upon animals, snowshoe hares (Lepus americanus) have to balance conflicting demands of obtaining food at a high rate and avoiding predators. Adopting foraging behaviours to minimise predation risk may also lead to a decline in condition, and hence fecundity. Predictions of three hypotheses (condition constraint hypothesis, predator-avoidance constraint hypothesis, predation-sensitive foraging (PSF) hypothesis) were tested by comparing changes in the survival and condition of snowshoe hares on four experimental areas in winter during a cyclic peak and decline (1989–1993) near Kluane Lake, Yukon, Canada, where (i) predation risk was reduced by excluding terrestrial predators (FENCE), (ii) food supply was supplemented with rabbit chow ad libitum (FOOD), (iii) these two treatments were combined (FENCE+FOOD), and (iv) an unmanipulated CONTROL was used. Different pattems of survival and changes in body mass were observed in the presence and absence of terrestrial predators. On the CONTROL area, female body mass and fecundity declined, even though sufficient winter forage was apparently available in all years. A similar decrease in body mass was observed on the FOOD treatment, but only during the third year of the population decline. In contrast, female body mass remained high throughout the decline in the absence of terrestrial predators in the FENCE+FOOD and FENCE treatments. Winter survival declined on CONTROL and FENCE areas during the first year of the population decline (1991), but remained higher on FOOD until 1992 and FENCE+FOOD until 1993. These results generally supported the PSF hypothesis where terrestrial predators were present (CONTROL and FOOD grids). Where terrestrial predators were absent (FENCE and FENCE+FOOD), the results supported the alternative condition constraint hypothesis. The evidence suggests that a cascade of sublethal behavioural and physiological effects associated with increased predation risk contribute to the population decline and delayed recovery of cyclic low-phase populations of snowshoe hares.

Metabolism and evaporative water loss of Western Australian geckos (Reptilia : Sauria : Gekkonomorpha)

2000 ◽  
Vol 48 (2) ◽  
pp. 111 ◽  
Author(s):  
P. C. Withers ◽  
K. P. Aplin ◽  
Y. L. Werner
Keyword(s):  
Linear Regression ◽  
Body Mass ◽  
Water Use ◽  
Water Loss ◽  
Phylogenetic Analyses ◽  
Resting Metabolic Rate ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Regression Residuals ◽  
Western Australian

Resting metabolic rate (RMR) and evaporative water loss (EWL) were measured, and resistance (R) to evaporative water loss and water use index (WUI = EWL/RMR) were calculated, for 22 species of Western Australian gecko. For all available gecko data, body mass and temperature explained 85% of the variability in RMR (=14.5 mass0.833 100.0398 Ta µL h–1), and 70% of the variability in EWL (=0.126 mass0.539 100.049 Ta mg h–1 ). For Western Australian geckos, RMR and EWL were significantly influenced by body mass, using conventional regression and phylogenetic analyses. Resistance to evaporative water loss (R) was not significantly affected by body mass. Water use index was inversely related to body mass: WUI = 21.9 M–0.344 mg mL O2–1. There were significant differences between species for R and for standardised residuals of RMR, EWL and WUI. R was not correlated with phylogeny, and was significantly higher (P = 0.020) for saxicolous geckos (1467 s cm-1) than terrestrial geckos (797 s cm–1); arboreal geckos had an intermediate R (977 s cm–1). Species that ate termites had lower standardised linear regression residuals (P = 0.003) for RMR than did species that ate more general diets. Standardised residuals for EWL were almost significantly related to microhabitat (P = 0.053). Standardised residuals for WUI were significantly related to microhabitat (P = 0.016); saxicolous species had lower WUI than terrestrial species. Standardised linear regression residuals of the residuals from autoregression (which should be independent of both mass and phylogeny effects) still significantly correlated RMR and diet, but not EWL or WUI with microhabitat.

Influence of forest herbicide on snowshoe hare population dynamics: reproduction, growth, and survival

1996 ◽  
Vol 26 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Thomas P. Sullivan
Keyword(s):  
Body Mass ◽  
Demographic Parameters ◽  
Snowshoe Hare ◽  
Growth And Survival ◽  
Physiological Processes ◽  
Adult Females ◽  
Breeding Condition ◽  
Glyphosate Herbicide ◽  
Hare Population ◽  
Treatment Population

This study was designed to assess the influence of forest applications of glyphosate herbicide on reproduction, growth, and survival in snowshoe hare (Lepusamericanus Erxleben) populations in control (reference) and treatment habitats near Prince George, B.C. Proportion of adult hares in breeding condition and number of successful pregnancies showed no consistent differences between control and treatment populations. Recruitment of hares was generally similar except for significantly more juvenile females entering the control than treatment population at one study area. At a second study area, total recruitment was significantly higher in the treatment than control population for both sexes in 1990 and for adult females in 1991, the 2 post-treatment years. There was little difference in survival of hares between control and treatment populations. Lack of significant differences in mean body mass and growth rates suggested that this herbicide treatment had little or no effect on metabolic or general physiological processes in the development of young hares. Similar profiles of body mass distribution between control and treatment populations indicated that comparable levels of biomass of hares were available as prey for predators. Use of this forest herbicide did not measurably affect demographic parameters of snowshoe hare populations.

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