Assessment of the potential for competition between two sympatric herbivores - the northern hairy-nosed wombat, Lasiorhinus krefftii, and the eastern grey kangaroo, Macropus giganteus

2000 ◽  
Vol 27 (3) ◽  
pp. 301 ◽  
Author(s):  
Andrew P. Woolnough ◽  
Christopher N. Johnson
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Dietary Overlap ◽  
Single Population ◽  
Habitat Features ◽  
Plant Parts ◽  
Grey Kangaroo ◽  
Regression Techniques ◽  
Similar Body ◽  
Social Marking

The northern hairy-nosed wombat, Lasiorhinus krefftii, is a critically endangered grazing herbivore, restricted to a single population of just 65 individuals in the savanna of central Queensland. Lasiorhinus krefftii shares its habitat with another grazing herbivore of similar body size, the eastern grey kangaroo, Macropus giganteus. This study investigated the potential for M. giganteus to compete with L. krefftii for food. Analysis of faecal residues demonstrated that both herbivores consumed grass almost exclusively, with the exception of small quantities of sedges and dicotyledons. Dietary overlap between M. giganteus and L. krefftii was high, both in the consumption of plant species (90%) and plant parts (99%), suggesting that there is potential for dietary competition. Using the distribution of faecal deposits for both herbivores, analysis of habitat usage by multiple linear regression techniques indicated that M. giganteus exhibits clear associations with some habitat features but proved inconclusive for L. krefftii because of their use of defecation in social marking. However, an examination of the population dynamics of M. giganteus suggested that the densities reported in this study, although highly seasonal, are sufficiently low that competition with L. krefftii for food is currently negligible.

Structural adaptations of bovine ungulates modern agrocenosis

2021 ◽  
Vol 1 (11) ◽  
pp. 6-15
Author(s):  
Sergey V. Posyabin ◽  
◽  
Elena N. Borkhunova ◽  
Vladislav V. Belogurov ◽  
Mikhail D. Kachalin ◽  
...  
Keyword(s):  
Body Size ◽  
Forest Soils ◽  
Distal Part ◽  
Static Load ◽  
High Weight ◽  
Morphometric Characteristics ◽  
Structural Adaptation ◽  
Solid Soil ◽  
Similar Body ◽  
Structural Adaptations

The article presents the results of studies of anatomical, histological and morphometric characteristics of bovine ungulates aimed at identifying signs of structural adaptation of the distal part of the limb to anthropogenically modeled content conditions. The factors that the hoof experiences are the predominance of static load, the high weight of the animal, and the support on solid soil. As a morphological control, elk is considered as a parrotfish animal with similar body size and weight, located in the conditions of natural biotsenose and moving on forest soils. It is shown that constant presence of cattle in conditions of hypokinesia on hard floors leads to change of limb setting and change of hoof shape, which is reflected in change of hoof shape, increase of hoof angle, ratio of plantar and dorsal hoof surfaces length. At the same time, the biomechanical load is redistributed between parts of the hoof so that the load on the wall increases and on the ball decreases. This may be a factor predisposing the hoof to the appearance of microtraumas, later manifested by laminites.

scholarly journals Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)

2006 ◽  
Vol 58 (4) ◽  
pp. 562-566 ◽  
Author(s):  
C. Reigada ◽  
W.A.C. Godoy
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Body Size ◽  
Larval Density ◽  
Chrysomya Megacephala ◽  
Life History Characteristics ◽  
Two Temperatures ◽  
Biological Aspects ◽  
Experimental Populations ◽  
Simultaneous Influence

The effect of larval density on the survival, fecundity and body size at two temperatures in experimental populations of C. megacephala was studied. No effect from simultaneous influence of density and temperature on life history characteristics of C. megacephala was found. Significant effects of density and temperature on survival, fecundity and body size were observed. The importance of these results for the population dynamics of C. megacephala is discussed.

Statistical Techniques for Interpreting Body Size–Related Exercise Performance during Growth

2000 ◽  
Vol 12 (2) ◽  
pp. 112-127 ◽  
Author(s):  
Joanne R. Welsman ◽  
Neil Armstrong
Keyword(s):  
Body Size ◽  
Linear Regression ◽  
Body Mass ◽  
Exercise Performance ◽  
Multilevel Regression ◽  
Cross Sectional ◽  
Regression Techniques ◽  
Ontogenetic Allometry ◽  
Log Linear ◽  
Individual Size

This paper reviews some of the statistical methods available for controlling for body size differences in the interpretation of developmental changes in exercise performance. For cross-sectional data analysis simple per body mass ratio scaling continues to be widely used, but is frequently ineffective as the computed ratio remains correlated with body mass. Linear regression techniques may distinguish group differences more appropriately but, as illustrated, only allometric (log-linear regression) scaling appropriately removes body size differences while accommodating the heteroscedasticity common in exercise performance data. The analysis and interpretation of longitudinal data within an allometric framework is complex. More established methods such as ontogenetic allometry allow insights into individual size-function relationships but are unable to describe adequately population effects or changes in the magnitude of the response. The recently developed multilevel regression modeling technique represents a flexible and sensitive solution to such problems allowing both individual and group responses to be modeled concurrently.

scholarly journals The body-size dependence of mutual interference

2014 ◽  
Vol 10 (6) ◽  
pp. 20140261 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Size Dependence ◽  
Empirical Support ◽  
Mutual Interference ◽  
The Body ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Body Sizes ◽  
Size Scales

The parameters that drive population dynamics typically show a relationship with body size. By contrast, there is no theoretical or empirical support for a body-size dependence of mutual interference, which links foraging rates to consumer density. Here, I develop a model to predict that interference may be positively or negatively related to body size depending on how resource body size scales with consumer body size. Over a wide range of body sizes, however, the model predicts that interference will be body-size independent. This prediction was supported by a new dataset on interference and consumer body size. The stabilizing effect of intermediate interference therefore appears to be roughly constant across size, while the effect of body size on population dynamics is mediated through other parameters.

scholarly journals Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

2011 ◽  
Vol 278 (1721) ◽  
pp. 3142-3151 ◽  
Author(s):  
Tanya L. Russell ◽  
Dickson W. Lwetoijera ◽  
Bart G. J. Knols ◽  
Willem Takken ◽  
Gerry F. Killeen ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Population Growth ◽  
Vector Control ◽  
Anopheles Gambiae ◽  
Phenotypic Expression ◽  
Phenotypic Traits ◽  
Density Dependent ◽  
Individual Fitness ◽  
The Impact

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% w AIC c support). The individual phenotypic expression of the maternal ( p = 0.0001) and current ( p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness.

The Diet of the Eastern Grey Kangaroo and Wallaroo in Areas of Improved and Native Pasture in the New England Tablelands.

1983 ◽  
Vol 10 (2) ◽  
pp. 203 ◽  
Author(s):  
RJ Taylor
Keyword(s):  
New England ◽  
New South ◽  
New South Wales ◽  
Plant Parts ◽  
South Wales ◽  
Grey Kangaroo ◽  
Native Pasture ◽  
Tussock Grasses

The diet of the eastern grey kangaroo and wallaroo was compared at 2 sites, Lana and Newsholme, in the New England tablelands of New South Wales. At Lana, the pastures had been fertilized for 20 yr and were dominated by low-fibre grasses such as Bothriochloa, Eragrostis, Sporobolus, Microlaena, Danthonia and Vulpia; some paddocks had been sown with introduced grasses, Phalaris, Festuca and lucerne. Coarse tussock grasses such as Poa spp., Stipa and Danthonia pallida predominated at Newsholme. The major difference in the diet of the 2 spp. was in winter when individuals on the unimproved area at Newsholme ate a higher proportion of tussock grasses and less low-fibre grass. Both spp. consistently selected for low-fibre grass leaf; they did not differ in their use of plant parts. The diets contained many plant spp. in common, although there were major differences in the use of several spp. The plant spp. favoured only by the wallaroo were of a higher quality than those favoured only by the grew kangaroo.

Allometry and sexual dimorphism in the lung morphology of prairie rattlesnakes, Crotalus viridis viridis

1999 ◽  
Vol 20 (4) ◽  
pp. 377-389 ◽  
Author(s):  
J. Scott Keogh ◽  
V. Wallach
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Intraspecific Variation ◽  
Relative Length ◽  
Single Population ◽  
Crotalus Viridis ◽  
Lung Morphology ◽  
Body Sizes ◽  
Vascular Component

AbstractWe quantified sexual dimorphism and allometric changes in the lung morphology of 160 juvenile and adult specimens of prairie rattlesnake, Crotalus viridis viridis, from a single population. In virtually all lung components, those of males are located more posteriorly than are those of females of the same body size. Males display a longer vascular component than females but there is no sexual dimorphism in size of the avascular component. Thus, males generally have longer lungs than do females at all body sizes. With increasing body size, the lung components are found more anteriorly, relative length of the vascular lung decreases, and relative length of the avascular lung increases in both sexes. However, total lung length increases isometrically with body size. These sexual and allometric differences suggest that intraspecific variation should be taken into account when lung size characters are used in snake systematic studies.

Reproductive patterns of European pond turtles differ between sites: a small scale scenario

2015 ◽  
Vol 36 (4) ◽  
pp. 339-349
Author(s):  
Marco A.L. Zuffi ◽  
Elena Foschi
Keyword(s):  
Body Size ◽  
Egg Production ◽  
Shell Height ◽  
The Body ◽  
Small Scale ◽  
Central Mediterranean ◽  
Population Structures ◽  
Body Sizes ◽  
Reproductive Females ◽  
Similar Body

From 1996 to 2002, we studied the body size, measures of reproductive strategy (relative clutch mass and delayed reproduction at sexual maturity), and reproductive output (clutch frequency and annual egg production) of female European Pond turtles,Emys orbicularis, at two sites separated by 12 km in central Mediterranean Tuscany (San Rossore and Camp Darby, central northern Italy). Females did not reproduce at the first appearance of external sexual characters, but reproduced at larger sizes, probably as older turtles. Among years, reproductive females were more common than were non-reproductive females, yet both groups had similar body sizes. Body size (carapace length and width, plastron length and width, shell height and body mass) varied between localities and among years. Body size differed between reproductive and non reproductive females in Camp Darby, but not in San Rossore females. Shell volume did not vary among years, nor between localities, nor between reproductive status. Reproductive females had higher body condition indices (BCI) than did non-reproductive females, while BCI did not differ between females laying one clutch and females laying multiple clutches. Clutch size did not vary among years. One clutch per year was much more frequent than multiple clutches, and multiple clutches were more frequent in Camp Darby than in San Rossore females, likely due to differences in population structures between sites.

scholarly journals Population dynamics and body-size selection in Daphnia

1992 ◽  
Vol 37 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Alan J. Tessier ◽  
Andrew Young ◽  
Mathew Leibold
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Size Selection
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