Estimating the age of western grey kangaroos (Macropus fuliginosus ocydromus)

2018 ◽  
Vol 40 (2) ◽  
pp. 254 ◽  
Author(s):  
Chris Mayberry ◽  
Roberta Bencini ◽  
Peter R. Mawson ◽  
Shane K. Maloney
Keyword(s):  
Linear Relationship ◽  
Western Australia ◽  
Age Structure ◽  
Wild Population ◽  
Target Population ◽  
Population Management ◽  
Eye Lens ◽  
Foot Length

Scientific studies and population management may benefit from knowledge of the age structure of a target population. We evaluated traditional and newly developed methods of estimating the age of kangaroos with data from 336 western grey kangaroos (Macropus fuliginosus) culled from a wild population in south-western Australia. We compared their ages based on molar progression with data on head, leg, and foot length, a balanced sum of all three measures, dried eye-lens weight, and molar wear score, and derived formulae to estimate age from each variable. Molar wear score has a linear relationship to molar progression and therefore leads to similar estimations of age, but requires only one complete arcade of molars. Because the relationships between age and the lengths of head, foot and leg are curvilinear, these become less reliable indicators of age with increasing age but the accuracy can be improved by considering a combination of the lengths of head, foot, and leg. Estimation of age from dried lens weight is more accurate than estimation from morphometry. The use of morphometry to estimate the age of kangaroos older than two years is more reliable than previously thought and requisite data can be collected from live animals. Where lethal methods are needed to collect samples, a largely intact skull, a single arcade of molars, or the lens extracted from one eye can reliably be used to estimate age.

The Use of Eye-Lens Weights for Aging Wild Rabbits, Oryctolagus cuniculus (L.), in Australia

1980 ◽  
Vol 7 (1) ◽  
pp. 79 ◽  
Author(s):  
SH Wheeler ◽  
DR King
Keyword(s):  
Western Australia ◽  
Oryctolagus Cuniculus ◽  
Wild Population ◽  
Eye Lens ◽  
Eastern Australia ◽  
Western Australian ◽  
Regional Curves

Eye-lens weight-age relationships were determined for rabbits from a wild population and from an enclosed population (of the same stock) in south-western Australia. Previously published curves of lens weight v. age for rabbits in eastern Australia are not entirely satisfactory models for the western Australian data. However, the differences, though obvious, are minor, and for general aging any of the published curves are adequate. For accurate aging, regional curves may have to be determined.

Estimating the age structure of a population of brushtail possums (Trichosurus vulpecula) by comparing tooth wear and cementum lines

2011 ◽  
Vol 33 (1) ◽  
pp. 52 ◽  
Author(s):  
Cheryl A. Lohr ◽  
Tammy Esmaili ◽  
Harriet Mills ◽  
Roberta Bencini
Keyword(s):  
Western Australia ◽  
Age Structure ◽  
Wild Population ◽  
Age Distribution ◽  
Tooth Wear ◽  
Trichosurus Vulpecula ◽  
Rank Regression ◽  
Parametric Data ◽  
Free Ranging ◽  
The Relationship

We used cementum lines from a sample of possums to calibrate tooth wear patterns in free-ranging common brushtail possums (Trichosurus vulpecula) to estimate of the age structure of a wild population of the species living at the Perth Zoo, Western Australia. We assessed patterns of tooth wear and incremental cementum lines in teeth extracted from 40 possums via necropsy. Rank regression for non-parametric data revealed a weak relationship between the number of cementum lines per tooth (y), which was assumed to correspond to the age of the possums (in years), and tooth wear (males: age = 0.51x + 3.4, r2 = 0.098, n = 27; females: age = 1.17x + 0.35, r2 = 0.345, n = 45). We used these relationships and the tooth wear pattern of 149 live possums caught at Perth Zoo to develop an estimate of the age structure of the population. Most (63.1%) possums were between 4 and 6 years of age. Very few young (1–2 years) or old (6–8 years) possums were caught at Perth Zoo. These results yielded an approximate age distribution for possums within Perth Zoo and should be used with caution because the relationship between the number of cementum lines and tooth wear was weak.

Bill Shape and Size in Honeyeaters and other small Insectivorous Birds in Western Australia

1984 ◽  
Vol 32 (5) ◽  
pp. 657 ◽  
Author(s):  
RD Wooller
Keyword(s):  
Linear Relationship ◽  
Body Mass ◽  
Western Australia ◽  
Clear Relationship ◽  
Cube Root ◽  
Insectivorous Birds ◽  
Flying Insects ◽  
Bill Length ◽  
Shape And Size

Highly nectarivorous honeyeaters, more insectivorous honeyeaters and non-honeyeater insectivores all showed a similar linear relationship between bill length and the cube root of body mass. Bill length increased with body mass at a faster rate in insectivorous honeyeaters than in insectivorous non- honeyeaters. In the more nectarivorous honeyeaters there was no clear relationship between bill length and either bill depth or body mass. It is suggested that mechanical considerations associated with taking large insects from surfaces restrict the length of the bill in both insectivorous non-honeyeaters and, to a lesser extent, in insectivorous honeyeaters. The longer bills of highly specialized honeyeaters may largely restrict them to small flying insects.

The population of the whelk Dicathais aegrota in Western Australia

1969 ◽  
Vol 20 (3) ◽  
pp. 225 ◽  
Author(s):  
BF Phillips
Keyword(s):  
Mortality Rate ◽  
Population Study ◽  
Western Australia ◽  
High Mortality ◽  
Age Structure ◽  
Environmental Stresses ◽  
Intertidal Communities ◽  
Size And Age Structure ◽  
The Individual ◽  
Reef Platform

The reproduction, growth, mortality, and physical tolerances of the individual Dicathais aegrota are described and integrated with the results of a population study on intertidal reef platforms at Rottnest I. Although exposed to severe environmental stresses, the population on the reef platform remained relatively stable in size and age structure during the period of this investigation. A high mortality rate (greater than 70% of the population per annum) was counterbalanced by continuous recruitment of juveniles and the immigration of a small number of adults, both from the sublittoral area. The discovery that this species extends into the sublittoral area and relies upon that segment of the population to maintain those upon the reef platform, indicates a need for review of existing concepts of mortality and survival of intertidal communities.

Biometrics, sexing criteria, age-structure and moult of Sooty Oystercatchers in south-eastern and north-western Australia

2009 ◽  
Vol 109 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Birgita D. Hansen ◽  
Clive D. T. Minton ◽  
Rosalind Jessop ◽  
Peter Collins
Keyword(s):  
Western Australia ◽  
Age Structure ◽  
South Eastern ◽  
North Western

scholarly journals Fetal Foot Length and Femur/ Foot Length Ratio: Significance in Nepalese Context

2012 ◽  
Vol 1 (1) ◽  
pp. 15-22 ◽  
Author(s):  
KS Joshi ◽  
SB Marahatta ◽  
S Karki ◽  
S Tamrakar ◽  
NC Shrestha
Keyword(s):  
Linear Relationship ◽  
Gestational Age ◽  
Cross Sectional Study ◽  
Length Ratio ◽  
Normal Infant ◽  
Cross Sectional ◽  
Femur Length ◽  
Foot Length ◽  
Final Study ◽  
Study Population

Aim: 1. To assess relationship between fetal foot length and gestation age and develop a nomogram. 2. To assess relationship between fetal foot length and femur length. Meterials and Method: Cross sectional study. Fetal foot length was taken from the skin edge overlying calcaneus to the distal end of the longest toe on either plantar or the sagittal view in 860 singleton pregnant women between 15 and 40 weeks’ gestation. Normal case was defined as normal sonographic findings during examination and normal infant examination at birth or both. Final study population constituted 779 healthy fetuses. The relationship between gestational age to foot length was analyzed by simple linear regression. Correlation of fetal foot length with gestational age and femur length were also obtained. Results: A nomogram for fetal foot length was obtained. There is linear relationship between foot length and gestational age [foot length (mm)=2.494xGestational age (weeks)-15.46] with significant correlation (r=0.970 and p=0.000) and between foot length and femur length [foot length(mm)=1.049xfemur length (mm)+0.648] with significant correlation (r=0.980 and P=0.000). Femur length/ Foot Length ratio was 0.9 and 1.0 in most of the cases. Conclusion: Nomogram was obtained for fetal foot length at various gestational ages in our population. There is linear relationship and good correlation between foot length and gestational age and foot length and femur length. Fetal foot length can be used as an alternative fetal parameter to assess gestational age. Femur length/ Foot Length ratio is fairly constant throughout gestation. DOI: http://dx.doi.org/10.3126/njr.v1i1.6317 Nepalese Journal of Radiology Vol.1(1): 15-22

A systematic review of ground-based shooting to control overabundant mammal populations

2020 ◽  
Vol 47 (3) ◽  
pp. 197
Author(s):  
Andrew J. Bengsen ◽  
David M. Forsyth ◽  
Stephen Harris ◽  
A. David M. Latham ◽  
Steven R. McLeod ◽  
...  
Keyword(s):  
Population Control ◽  
A Priori ◽  
Population Decline ◽  
Target Population ◽  
Geographic Area ◽  
Population Management ◽  
Management Tool ◽  
Detectable Effect ◽  
Management Intervention ◽  
Wildlife Populations

Abstract Context Ground-based shooting is widely used in management programs aiming to alleviate the impacts of invasive or overabundant wildlife populations. However, evaluations of individual shooting operations have shown variable results, and the effectiveness of ground-shooting as a population-management intervention has not been systematically examined. Aims Our review aimed to (1) assess the efficacy of shooting as a population management tool, and (2) identify commonalities among studies that will help managers identify situations where ground-shooting is most likely to be effective. Methods We systematically reviewed the literature to identify studies involving ground-shooting. From each study, we collated information about operational objectives, target taxa, geographic context, type of shooter used, effort, effectiveness, and use of additional control tools. Key results Most studies had no a priori quantifiable objectives. However, 60% of the 64 case studies produced a detectable reduction in population density and/or damage. The most common type of operation used unpaid or commercial harvest-oriented shooters to reduce herbivore density or damage. Only 30% of the operations that used volunteer shooters or recreational hunters achieved their objectives. Target taxa, geographic area or integration of shooting with other population-control methods had no detectable effect on the effectiveness of shooting operations. Common factors that hindered the effectiveness of shooting operations included immigration of target species from adjacent areas (n=13), decreasing effort from shooters as the target population declined (n=7) and selective harvesting (n=7). Conclusions Ground-based shooting can be an effective management tool for overabundant wildlife populations, but many shooting operations did not achieve a notable decrease in animal abundance or damage. The source of failure could often be attributed to an inability to remove a sufficient proportion of the population to cause a population decline. Implications Managers contemplating using ground-based shooting to reduce the impacts or density of wildlife populations should (1) carefully consider whether this is a suitable management tool to achieve the desired outcomes, (2) establish clear objectives that aim to meet defined outcomes and allow for continuous improvement, and (3) ensure that operations are sufficiently resourced to achieve and maintain those objectives.

scholarly journals The impacts of different management strategies and environmental forcing in ecological communities

2006 ◽  
Vol 273 (1600) ◽  
pp. 2491-2499 ◽  
Author(s):  
Katja Enberg ◽  
Mike S Fowler ◽  
Esa Ranta
Keyword(s):  
Species Interactions ◽  
Management Strategies ◽  
Single Species ◽  
Target Population ◽  
Population Management ◽  
Community Response ◽  
Ecological Communities ◽  
Target Species ◽  
Community Members ◽  
Environmental Forcing

Understanding the effects of population management on the community a target species belongs to is of key importance for successful management. It is known that the removal or extinction of a single species in a community may lead to extinctions of other community members. In our study, we assess the impacts of population management on competitive communities, studying the response of both locally stable and unstable communities of varying size (between four and 10 species) to three different management strategies; harvesting of a target species, harvesting with non-targeted catch, and stocking of the target species. We also studied the consequences of selecting target species with different relative abundances, as well as the effects of varying environmental conditions. We show here how the effects of management in competitive communities extend far beyond the target population. A crucial role is played by the underlying stability properties of the community under management. In general, locally unstable communities are more vulnerable to perturbation through management. Furthermore, the community response is shown to be sensitive to the relative density of the target species. Of considerable interest is the result that even a small (2.5%) increase in the population size of the target species through stocking may lead to extinction of other community members. These results emphasize the importance of considering and understanding multi-species interactions in population management.

A Study on Middle-Income Population Measurement Model and Methods

2014 ◽  
Vol 644-650 ◽  
pp. 5498-5504
Author(s):  
Tian Jiu Leng ◽  
Tai Xiang
Keyword(s):  
Growth Rate ◽  
Markov Chain ◽  
Linear Relationship ◽  
Age Structure ◽  
Population Model ◽  
Measurement Model ◽  
Middle Income ◽  
Differential Model ◽  
Net Growth Rate ◽  
Future Population

Through improving the Logistic population model, this paper sets a linear relationship between the net growth rate of the population and time, gets a differential model for predicting the future population, and uses Markov chain for predicting the age structure of the population in China

scholarly journals Age estimation of pouch young and growth of the burrowing bettong, Bettongia lesueur, (Marsupialia: Potoroidae) on Heirisson Prong, Shark Bay, Western Australia

2007 ◽  
Vol 29 (2) ◽  
pp. 157 ◽  
Author(s):  
C.J. Freegard ◽  
M.C. Calver ◽  
J.D. Richards ◽  
J.S. Bradley
Keyword(s):  
Western Australia ◽  
Morphological Characteristics ◽  
Tail Length ◽  
Growth Function ◽  
Slow Phase ◽  
Adult Size ◽  
Rapid Phase ◽  
Shark Bay ◽  
Foot Length ◽  
Hind Foot

Measurements of hind foot length, weight, head length and tail length were collected from pouch young, young at foot, sub-adults and adults of a reintroduced population of the vulnerable burrowing bettong, Bettongia lesueur, on Heirisson Prong, Shark Bay, Western Australia. A key based on qualitative characteristics was used to age individuals and a Richards growth function was fitted to plots of hind foot length versus age. The patterns of growth and morphological characteristics were similar for males and females. Both sexes exhibited a growth pattern typical of a medium-sized macropod with an initial slow phase of growth followed by a rapid phase that slowed as adult size was reached. The growth curves are suitable for broad estimates of the age of wild-caught animals from pouch young to early adulthood.

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