scholarly journals Body size of female calves and natality rates of known-aged females in two adjacent Alaskan caribou herds, and implications for management

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 203 ◽  
Author(s):  
Patrick Valkenburg ◽  
Robert W. Tobey ◽  
Robert W. Tobey ◽  
Bruce W. Dale ◽  
Bruce W. Dale ◽  
...  
Keyword(s):  
Body Size ◽  
Population Growth ◽  
Body Mass ◽  
Real Option ◽  
Rangifer Tarandus ◽  
Herd Size ◽  
Adult Females ◽  
Potential Population ◽  
Newborn Calves ◽  
Natality Rate

We studied body mass of female calves and natality rate of adult females in two adjacent Interior Alaskan caribou (Rangifer tarandus granti) herds during 1991-2001. Mass of newborn calves was similar in both herds, but Delta calves gained significantly more mass over summer than Nelchina calves. In contrast, Nelchina calves consistently maintained their mass during winter while Delta calves lost mass. Metatarsus length was similar in both herds in 4-month-old and 10-month-old calves, and it increased over winter in both herds. Natality rates of females >3 years old were consistently higher in the Delta Herd than in the Nelchina Herd, primarily because natality in 3- to 5-year-old Nelchina females was low. Although body mass of Delta Herd calves consistently declined over winter, we concluded that nutrition was not significantly limiting herd growth. Managers are more likely to maximize harvest by maintaining the Delta Herd near its present size (i.e., 3500), or allowing it to increase only slightly. The only real option for increasing harvestable surpluses of caribou in the Delta Herd is reducing predation during calving and summer. In contrast, we conclude that summer nutrition significantly limits potential population growth and body mass in the Nelchina Herd, and managers are more likely to maximize harvest by maintaining herd size at or below 30 000 than by allowing the herd to grow to near historical highs (i.e., 60 000-70 000).

Body composition and nutrient reserves of arctic caribou

1996 ◽  
Vol 74 (1) ◽  
pp. 136-146 ◽  
Author(s):  
K. L. Gerhart ◽  
R. G. White ◽  
R. D. Cameron ◽  
D. E. Russell
Keyword(s):  
Growth Rate ◽  
Body Composition ◽  
Chemical Composition ◽  
Body Mass ◽  
Seasonal Changes ◽  
Rangifer Tarandus ◽  
Post Partum ◽  
Growth Patterns ◽  
Chemical Components ◽  
Adult Females

We determined seasonal changes in body mass and composition of arctic caribou (Rangifer tarandus granti) in relation to age and reproductive status. Chemical composition was determined for 37 caribou calves from the Central Arctic Herd ranging from 1 to 134 days of age and for 15 adult females collected from the same herd in October, May, and July. Body composition of 5 fetuses from the Central Arctic Herd, 13 calves from the Porcupine Herd, and 10 captive male reindeer (R. t. tarandus) was determined for comparison. Between October 1989 and May 1990, body fat and protein of adult females declined by maxima of 45 and 29%, respectively; an additional 32% of fat was lost between May and July. Mobilization of large amounts of fat and protein suggests winter undernutrition. Chemical composition and growth patterns of calves did not differ between the herds. The growth rate of Central Arctic Herd calves was high during the first 28 d post partum (402 g/d), but both growth rate and fatness declined between 4 and 6 weeks of age (to 306 and −18.3 g/d, respectively), perhaps in response to insect harassment. Birth masses of males and females did not differ, but by autumn, male calves were 9.1 kg heavier than females. Chemical components (water, fat, protein, ash) were highly correlated with body mass, ingesta-free body mass, and carcass mass. Percentages of fat and water were inversely related, but the intercept decreased with age. Marked seasonal hypertrophy of liver and kidneys was noted in caribou, suggesting the presence of mobilizable protein reserves. Seasonal changes in organ masses may also reflect variations in metabolic activity and nutrient intake.

scholarly journals The scaling of expansive energy under the Red Queen predicts Cope’s Rule

2019 ◽  
Author(s):  
Indrė Žliobaitė ◽  
Mikael Fortelius
Keyword(s):  
Body Size ◽  
Population Growth ◽  
Body Mass ◽  
Limiting Factor ◽  
Large Species ◽  
Small Species ◽  
Evolutionary Advantage ◽  
Zero Sum ◽  
The Red Queen ◽  
Cope’S Rule

AbstractThe Red Queen’s hypothesis portrays evolution as a never-ending competition for expansive energy, where one species’ gain is another species’ loss. The Red Queen is neutral with respect to body size, implying that neither small nor large species have a universal competitive advantage. The maximum population growth in ecology; however, clearly depends on body size – the smaller the species, the shorter the generation length, and the faster it can expand. Here we ask whether, and if so how, the Red Queen’s hypothesis can accommodate a spectrum of body sizes. We theoretically analyse scaling of expansive energy with body mass and demonstrate that in the Red Queen’s zero-sum game for resources, neither small nor large species have a universal evolutionary advantage. We argue that smaller species have an evolutionary advantage only when resources in the environment are not fully occupied, such as after mass extinctions or following key innovations allowing expansion into freed up or previously unoccupied resource space. Under such circumstances, we claim, generation length is the main limiting factor for population growth. When competition for resources is weak, smaller species can indeed expand faster, but to sustain this growth they also need more resources. In the Red Queen’s realm, where resources are fully occupied and the only way for expansion is to outcompete other species, acquisition of expansive energy becomes the limiting factor and small species lose their physiological advantage. A gradual transition from unlimited resources to a zero-sum game offers a direct mechanistic explanation for observed body mass trends in the fossil record, known as Cope’s Rule. When the system is far from the limit of resources and competition is not maximally intense, small species take up ecological space faster. When the system approaches the limits of its carrying capacity and competition tightens, small species lose their evolutionary advantage and we observe a wider range of successful body masses, and, as a result, an increase in the average body mass within lineages.

scholarly journals What Happened to the Beverly Caribou Herd after 1994?

ARCTIC ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 407 ◽  
Author(s):  
Jan Adamczewski ◽  
Anne Gunn ◽  
Kim G. Poole ◽  
Alexander Hall ◽  
John Nishi ◽  
...  
Keyword(s):  
Rangifer Tarandus ◽  
Alternative Explanation ◽  
Herd Size ◽  
Barren Ground ◽  
Management Actions ◽  
The North ◽  
Large Size ◽  
Ground Survey ◽  
Newborn Calves ◽  
Rangifer Tarandus Groenlandicus

The Beverly herd was one of the first large migratory herds of barren-ground caribou (Rangifer tarandus groenlandicus) defined in northern Canada on the basis of annual return of breeding females to traditional calving grounds near Beverly Lake in Nunavut. In 1994, herd size was estimated at 276 000 ± 106 600 (SE) adult caribou, but monitoring was minimal from 1994 to 2007. The next calving ground survey in 2002 revealed that caribou densities had dropped by more than half since 1994; annual surveys following from 2007 to 2009 demonstrated an extreme decline in numbers of calving cows, and by 2011, no newborn calves were seen there. We examine two possible explanations for the declining use of the traditional Beverly calving grounds from 1994 until their abandonment by 2011. One explanation is that a true numerical decline in herd size occurred, driven in at least the later stages by low cow survival and poor calf productivity, which led the remaining Beverly cows to switch to the neighbouring Ahiak calving ground 250 km to the north in 2007 – 09 and join that herd. An alternative explanation is that the decline on the traditional Beverly calving grounds was largely due to a distributional shift to the north of the Beverly herd that may have begun in the mid-1990s. We suggest that the former explanation is the more likely and that the Beverly herd no longer exists as a distinct herd. We acknowledge that gaps in monitoring of Beverly and Ahiak caribou hamper definitive evaluation of the Beverly herd’s fate. The large size sometimes achieved by barren-ground caribou herds is not a guarantee of persistence; monitoring shortfalls may hamper management actions to address declines.

Body-condition dynamics in a northern ungulate gaining fat in winter

2009 ◽  
Vol 87 (5) ◽  
pp. 367-378 ◽  
Author(s):  
Serge Couturier ◽  
Steeve D. Côté ◽  
Jean Huot ◽  
Robert D. Otto
Keyword(s):  
Population Growth ◽  
Habitat Quality ◽  
Body Fat ◽  
Body Condition ◽  
Rangifer Tarandus ◽  
Herd Size ◽  
Summer Range ◽  
Long Term Trends ◽  
Individual Condition

Individual condition generally depends on density and is partly determined by habitat quality and climate. We studied long-term trends in the condition and productivity of female caribou ( Rangifer tarandus (L., 1758)) in two large migratory herds in the Quebec–Labrador peninsula (Canada), the George and the Feuilles herds. Females from the George herd were in better summer condition than those from the more abundant Feuilles herd in 2001–2002, while it was the opposite in 1988 when the Feuilles herd was less abundant than the George herd. Summer nutrition followed the same pattern between herds through time. Spring body condition of females in the George herd declined from 1976 to the mid-1980s during early population growth. Fall condition, however, did not change from 1983 to 2002 when caribou numbers first peaked and later declined. Pregnancy rates were inversely related to herd size in both herds. Vegetation quality (NDVI) in June was significantly related to body proteins in the fall. Albeit unusual for a northern ungulate, body fat increased from fall to spring in the George herd. We conclude that a relatively small and highly grazed summer range, as well as density-dependent effects, affected summer nutrition and the need to continue lipogenesis during winter.

Measurement of weasel body size

1991 ◽  
Vol 69 (8) ◽  
pp. 2277-2279 ◽  
Author(s):  
Donald R. Johnson
Keyword(s):  
Principal Component Analysis ◽  
Body Size ◽  
Body Mass ◽  
Body Length ◽  
Reliable Method ◽  
Principal Component ◽  
The Other ◽  
Young Males ◽  
Adult Females ◽  
Juvenile Males

Body size of long-tailed weasels (Mustela frenata) and short-tailed weasels (Mustela erminea) collected in northern and central Idaho was indexed using cranial length, zygomatic width, cranial mass, body mass, and body length (total less tail) as size variables. In comparison with the other variables, body length had lower and sometimes nonsignificant correlations with principal component 1 (PC1) scores of principal component analysis, suggesting that its further use as an index of body size for these species is inappropriate. Young males (6–9 months of age) of one or both species, similar in body size to adult females, occurred in all regions sampled. Because body size alone is not a reliable method of separating juvenile males from adult females, specimens identified as male lacking the baculum or tag information independently confirming sex are possibly misclassified.

scholarly journals Morphological determinants of jumping performance in the Iberian green frog

2019 ◽  
Vol 66 (4) ◽  
pp. 417-424
Author(s):  
Gregorio Moreno-Rueda ◽  
Abelardo Requena-Blanco ◽  
Francisco J Zamora-Camacho ◽  
Mar Comas ◽  
Guillem Pascual
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Fluctuating Asymmetry ◽  
Hind Limb ◽  
Limb Length ◽  
Age Classes ◽  
Jumping Performance ◽  
Hind Limbs ◽  
Selective Forces ◽  
Pelophylax Perezi

Abstract Predation is one of the main selective forces in nature, frequently selecting potential prey for developing escape strategies. Escape ability is typically influenced by several morphological parameters, such as morphology of the locomotor appendices, muscular capacity, body mass, or fluctuating asymmetry, and may differ between sexes and age classes. In this study, we tested the relationship among these variables and jumping performance in 712 Iberian green frogs Pelophylax perezi from an urban population. The results suggest that the main determinant of jumping capacity was body size (explaining 48% of variance). Larger frogs jumped farther, but jumping performance reached an asymptote for the largest frogs. Once controlled by structural body size, the heaviest frogs jumped shorter distances, suggesting a trade-off between fat storage and jumping performance. Relative hind limb length also determined a small but significant percentage of variance (2.4%) in jumping performance—that is, the longer the hind limbs, the greater the jumping capacity. Juveniles had relatively shorter and less muscular hind limbs than adults (for a given body size), and their jumping performance was poorer. In our study population, the hind limbs of the frogs were very symmetrical, and we found no effect of fluctuating asymmetry on jumping performance. Therefore, our study provides evidence that jumping performance in frogs is not only affected by body size, but also by body mass and hind limb length, and differ between age classes.

scholarly journals Ontogeny of body size and shape of Antarctic and subantarctic fur seals

2007 ◽  
Vol 85 (12) ◽  
pp. 1275-1285 ◽  
Author(s):  
Sebastián P. Luque ◽  
Edward H. Miller ◽  
John P.Y. Arnould ◽  
Magaly Chambellant ◽  
Christophe Guinet
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Morphological Traits ◽  
Body Shape ◽  
Size And Shape ◽  
Fur Seals ◽  
Fur Seal ◽  
Adult Body ◽  
Weaning Age ◽  
Lactation Duration

Pre- and post-weaning functional demands on body size and shape of mammals are often in conflict, especially in species where weaning involves a change of habitat. Compared with long lactations, brief lactations are expected to be associated with fast rates of development and attainment of adult traits. We describe allometry and growth for several morphological traits in two closely related fur seal species with large differences in lactation duration at a sympatric site. Longitudinal data were collected from Antarctic ( Arctocephalus gazella (Peters, 1875); 120 d lactation) and subantarctic ( Arctocephalus tropicalis (Gray, 1872); 300 d lactation) fur seals. Body mass was similar in neonates of both species, but A. gazella neonates were longer, less voluminous, and had larger foreflippers. The species were similar in rate of preweaning growth in body mass, but growth rates of linear variables were faster for A. gazella pups. Consequently, neonatal differences in body shape increased over lactation, and A. gazella pups approached adult body shape faster than did A. tropicalis pups. Our results indicate that preweaning growth is associated with significant changes in body shape, involving the acquisition of a longer, more slender body with larger foreflippers in A. gazella. These differences suggest that A. gazella pups are physically more mature at approximately 100 d of age (close to weaning age) than A. tropicalis pups of the same age.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

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