Dynamics of the new south wales yellow-footed rock­wallaby population, in relation to rainfall patterns

2000 ◽  
Vol 22 (1) ◽  
pp. 71 ◽  
Author(s):  
A Sharp ◽  
M Norton

Yellow-footed rock-wallabies (Petrogale xanthopus) are listed as endangered in New South Wales (NSW). Annual helicopter surveys have been conducted, during winter, on the NSW population since 1980. Correlation analysis suggested that the exponential rate of increase (r) of the population was positively related to rainfall in the previous calender year. Ivlev's inverted exponential numerical response model was found to adequately represent the relationship between r and rainfall, though the fit was poor (R2 = 0.43). Examination of the fit of the numerical response model and the predictions for the consonants used in the model suggested that the lower end of the function was better approximated than the upper end. The predicted values for the maximum rate of decrease and the level of rainfall at which r would became positive could be intuitively explained given aspects of the wallabies' ecology. However, the estimated maximum rate of increase was far below theoretically predicted values, which suggested that the expected positive correlation between rainfall and recruitment was weak. This suggested that the NSW P. xanthopus population was not primarily regulated by absolute resource availability during the period of the study. Possible intrinsic and extrinsic factors that detrimentally influenced the population are proposed.

1984 ◽  
Vol 11 (3) ◽  
pp. 415 ◽  
Author(s):  
J Caughley ◽  
P Bayliss ◽  
J Giles

Annual aerial counts of kangaroos within randomly selected blocks of the western plains of New South Wales showed that the numbers of kangaroos doubled between 1975-76 and 1982, and that the widespread drought of 1982 reduced the populations on average by 43%. Localized reductions of similar magnitude occurred after regional droughts in 1977 and 1980 within parts of the monitored area. The observed trends in kangaroo numbers, with eastern and western blocks treated separately, were correlated with annual rainfall with a time lag of 6 months in the response. The relationships show that kangaroos reach their maximum rate of increase following rainfall 100 mm above the annual average in the east and approximately 50 mm above the annual average in the west. At average annual rainfall kangaroos increase at 25% (greys) and 35% (reds) per annum in the east and at 25% (greys) and 30% (reds) per annum in the west. Rate of increase is zero when rainfall is 100 mm below average in the east and approximately 60 mm below average in the west. When rainfall is below these values, kangaroo numbers decline.


1981 ◽  
Vol 8 (2) ◽  
pp. 255 ◽  
Author(s):  
NC Shepherd

Over 7 weeks a group of five dingoes killed 83 red kangaroos within 150 m of a watering point in north-western New South Wales. All except three of these kangaroos were juveniles. Detailed autopsies were performed on 17 of the dead kangaroos: primary predation was the only significant gross pathological finding; the dingoes had eaten portions from about half the kangaroos killed. The daily rate of killing was estimated to be about 0.38 kg prey per kg predator. The rate of killing and the selection for juvenile kangaroos suggested that dingoes could have a direct effect on kangaroo densities by limiting rate of increase. The significance of this finding is discussed with reference to the difference in abundance of kangaroos between the New South Wales and Queensland sides of the border fence.


1970 ◽  
Vol 10 (47) ◽  
pp. 802 ◽  
Author(s):  
DW Turner

The effects of plastic bunch covers and varying defoliation treatments on bunch weight were measured on Williams bananas at Alstonville in north-eastern New South Wales. Bunch covers did not significantly affect bunch weight. The number of leaves left on the plant at bunch emergence only reduced yield when less than four leaves were present. Leaf length duration was calculated and was positively related to bunch weight. Bunch covers did not alter the relationship between leaf number and yield. The rate of sucker growth and water relations within the plants were altered by defoliation treatments. Both of these effects were greatest when less than three leaves were left on the plant.


2010 ◽  
Vol 14 (1) ◽  
pp. 34-43 ◽  
Author(s):  
Emily Banks ◽  
Louisa Jorm ◽  
Kris Rogers ◽  
Mark Clements ◽  
Adrian Bauman

AbstractObjectiveTo assess the relationship between obesity and sedentary behaviours, such as watching television or using a computer (‘screen-time’), and describe how this relationship varies between population subgroups.DesignCross-sectional analysis of the relationship between obesity (BMI ≥ 30 kg/m2) and screen-time, adjusted for age, sex, income and education and compared according to a range of personal characteristics.SettingNew South Wales, Australia.SubjectsA total of 91 266 men and women aged 45 years and above from the general population of New South Wales in 2006–2007 and providing self-reported information on height and weight and other factors.ResultsObesity prevalence was 21·4 %. Compared to individuals with <2 h of daily screen-time, the adjusted relative risks (RR) of obesity were 1·35 (95 % CI 1·26, 1·44), 1·70 (95 % CI 1·59, 1·82), 1·94 (95 % CI 1·81, 2·08) and 1·92 (95 % CI 1·80, 2·06) for 2–3, 4–5, 6–7 and ≥8 h, respectively. The increase in obesity with increasing screen-time was similar within categories of overall physical activity, but was attenuated in those in full-time paid work, compared to non-workers (P for interaction < 0·0001). Among non-workers, the overall obesity RR per 2 h increase in daily screen-time was 1·23 (95 % CI 1·21, 1·25) and was significantly elevated in all groups examined, ranging from 1·16 to 1·31 according to sex, level of age, education, income, smoking and fruit consumption. The RR did not differ significantly according to overall physical activity, region of residence and alcohol and vegetable consumption, but was substantially lower in disabled v. not-disabled individuals (P for interaction < 0·0001).ConclusionsObesity increases with increasing screen-time, independent of purposeful physical activity. This was observed in all population groups examined, although it is attenuated in full-time workers and disabled individuals.


2005 ◽  
Vol 45 (3) ◽  
pp. 269 ◽  
Author(s):  
D. F. Herridge ◽  
M. J. Robertson ◽  
B. Cocks ◽  
M. B. Peoples ◽  
J. F. Holland ◽  
...  

Apparent nodulation failures and associated low grain yields have been reported for commercial mungbean (Vigna radiata) crops in southern Queensland and northern New South Wales. We therefore conducted on-farm surveys of 40 commercial mungbean crops in the region in which symbiotic traits, i.e. nodulation and nitrogen fixation, and biomass and grain yield were monitored. Effects of bradyrhizobial inoculation and inoculation methods on mungbean and soybean (Glycine max) symbiosis and yield were determined in experiments at 3 sites in northern New South Wales. Thirty-four of the 35 mungbean crops assessed for nodulation were nodulated. The relationship between soil nitrate to a depth of 90 cm at sowing and mungbean nodulation was not significant. However, at low-to-moderate soil nitrate levels (<100 kg N/ha), the mean nodule score was 1.6, compared with 0.5 at high (>100 kg N/ha) soil nitrate levels. Soil nitrate had a negative effect on the percentage of mungbean nitrogen derived from nitrogen fixation (%Ndfa). Mean %Ndfa values for soil nitrate levels <50, >50–100 and >100 kg N/ha were 35, 22 and 19% respectively. Grain yields of the surveyed mungbean crops varied from 0.3 to 2.1 t/ha, and were correlated with shoot dry matter. Grain yield was not significantly correlated either with sowing soil nitrate, nodule score or %Ndfa. In the inoculation experiments, mungbean did not nodulate as well as soybean, producing about one-third the number of nodules. Both species responded to inoculation with increased nodulation, although data from one of the sites suggested that responses during early growth of mungbean were not maintained during pod-fill. Effects of inoculation on mungbean %Ndfa were marginal. Average increases were 9%, based on natural 15N abundance, and 6%, based on the ureide method. Soybean %Ndfa, on the other hand, responded strongly to inoculation, with increases of 56 (15N) and 77% (ureide). Inoculation increased mungbean crop N by an average of 10% and grain yield by 6%, compared with responses to fertiliser nitrogen of 31% (crop N) and 10% (grain yield). For soybean, inoculation increased crop nitrogen by 43% and grain yield by 7%, similar to responses to fertiliser nitrogen of 45 (crop N) and 5% (grain yield). These results suggest that inoculated mungbean was N-limited and that inoculation of mungbean using current technology may be somewhat ineffectual. We concluded that low nodulation and nitrogen fixation of commercial mungbean most likely results from the suppressive effects of nitrate and/or insufficient numbers of bradyrhizobia in the soil. When low symbiosis and low soil nitrate are combined, N is likely to limit crop growth, and potentially grain yield. Suggested strategies for improving mungbean nodulation and nitrogen fixation in the northern grains belt include selection of more symbiotically competent plant and bradyrhizobial genotypes and more effective utilisation of established soil populations of mungbean bradyrhizobia.


1995 ◽  
Vol 72 (1) ◽  
pp. 71-80 ◽  
Author(s):  
I.A. Neave ◽  
S.M. Davey ◽  
J.J. Russell-Smith ◽  
R.G. Florence

Obiter ◽  
2017 ◽  
Vol 38 (3) ◽  
Author(s):  
Angus Lloyd Hornigold

In South Africa, there is little authority on the relationship between the credit provider (bank) and the credit receiver (debtor) after a property has been declared executable and sold at an auction by the Sheriff of the Court following the debtor’s default on a loan underlying a mortgage bond. The Uniform Rules of Court may shortly be amended in order to allow a reserve price to be set at an auction. However, the bank may still be compelled to buy the property into possession (PIP) in order to preserve the asset so that it protects the interest of both itself and the debtor should this reserve price not be met by third party purchasers. This amendment is therefore unlikely to address the underlying problems that exist when a bank elects to buy a property at an auction. The authority that does exist provides that the banks stand in a different position vis-à-vis the debtor to that of a third party purchaser. Most notably, it provides that the bank has a duty to credit the proceeds of any sale, when the property is sold from its stock of PIPs to the account of the debtor. This appears to be correct, but there should be a sound theoretical foundation for this proposition. What further duties are owed to the debtor by the bank in these circumstances? In order to address this question, certain suggestions are made based on the New South Wales legal position.


Sign in / Sign up

Export Citation Format

Share Document