Population Dynamics of the Australian Plague Locust, Chortoicetes Terminifera (Walker) in Central Western New South Wales. Ii. Factors Influencing Natality and Survival.

1982 ◽  
Vol 30 (2) ◽  
pp. 199 ◽  
Author(s):  
RA Farrow
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Natural Enemies ◽  
New South ◽  
New South Wales ◽  
Development Stages ◽  
Factors Influencing ◽  
South Wales ◽  
Savannah Woodland ◽  
Australian Plague Locust

Unrealized natality and mortalities at successive development stages were measured during synchronized breeding by populations of the Australian plague locust. Studies were made over a 3-y period, covering nine generations, on small plots situated in pastures derived originally from savannah woodland in central western New South Wales. Variations in natality and mortalities were influenced more by variation in soil moisture, primarily through its effect on pasture conditions, than by the effects of natural enemies; these variations were closely correlated with seasonal rainfall. Unidentified losses, independent of known variables, were recorded in the hopper stage and were highest in the hatchling. Such losses invariably exceeded 60% even under the most favourable conditions encountered in the field during the study period. The quantitative relationships established in this study between the plague locust and its natural enemies and other environmental factors suggest that prospects for the biological control of this pest by either native or introduced species are poor.

scholarly journals Lifetime reproductive success in a population of female red kangaroos Macropus rufus in the sheep rangelands of western New South Wales: Environmental effects and population dynamics

2004 ◽  
Vol 26 (1) ◽  
pp. 45 ◽  
Author(s):  
AD Bilton ◽  
DB Croft
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
New South ◽  
New South Wales ◽  
Reproductive Potential ◽  
Lifetime Reproductive Success ◽  
South Wales ◽  
Macropus Rufus ◽  
Initial Starting

Female reproductive success and the recruitment of offspring to the next generation are key components of animal population dynamics. With an annual commercial harvest of between 13 and 22% of the red kangaroo (Macropus rufus) population, it is increasingly important that these processes are understood. We used data on the reproductive success of 33 free-ranging female M. rufus on Fowlers Gap station in far western New South Wales to determine the expected lifetime reproductive success (LRS) of females within an unharvested population. We also designed a model to generate predictions about female LRS incorporating empirical relationships between a mother?s reproductive success and maternal age, environmental conditions and the sex and survivorship of a previous reproductive attempt. Results from observations on female LRS (calculated from annual weaning rates) and those generated by the model predict that female M. rufus on ?Fowlers Gap? wean, on average, 3.7 young in a lifetime (ranges 0 - 11 and 0 - 20, respectively); representing only 41% of their maximum reproductive potential. Manipulation of initial starting conditions allowed the effect of varying environmental conditions on female LRS to be explored. The condition of the environment when females commence breeding does not appear to significantly affect their overall lifetime reproductive output. However, the occurrence of drought does. Females experiencing two droughts in a lifetime did not live as long and weaned fewer offspring and grandoffspring (from their daughters) than those females experiencing only one drought in a lifetime. In addition to the adverse effect of drought on the reproductive success of female M. rufus in this study, we suggest that, given the relatively high and stable population densities of M. rufus on ?Fowlers Gap?, other mechanisms (acting primarily on juvenile survival) must exist which limit population growth.

Movements of Sympatric Red Kangaroos, Macropus-Rufus, and Western Grey Kangaroos, Macropus-Fuliginosus, in Western New-South-Wales

1988 ◽  
Vol 15 (3) ◽  
pp. 339 ◽  
Author(s):  
D Priddel ◽  
G Wellard ◽  
N Shepherd
Keyword(s):  
Population Dynamics ◽  
National Park ◽  
New South ◽  
New South Wales ◽  
South Wales ◽  
Macropus Rufus

Between July 1979 and November 1980 a total of 261 red kangaroos, Macropus rufus, (216F; 45 M) and 170 western grey kangaroos, M. fuliginosus, (136F;34M) were caught and tagged with individually recognisable collars. Between July 1979 and January 1986, 1751 sightings of tagged individuals were recorded. Information gained from these sightings was used to assess how far each kangaroo ranged. More than 90% of individuals of either species did not range far (<9 km for reds; <6 km for western greys) even when local pastures were severely depleted during drought. A few individuals dispersed much further-up to 323 km. On average, red kangaroos ranged further than western greys. Kangaroos on Kinchega National Park ranged no less or no further than those on an adjacent pastoral leasehold. At least 17 tagged individuals crossed the macropod-deterrent fence surrounding Kinchega; several crossed repeatedly. Dispersal of kangaroos from Kinchega was slight, supporting the hypothesis of Bayliss (1985) that dispersal has no significant impact on population dynamics.

Effects of climate, natural enemies and biocides on three citrus mites in coastal New South Wales

1991 ◽  
Vol 11 (4) ◽  
pp. 271-295 ◽  
Author(s):  
G. A. C. Beattie ◽  
E. A. Roberts ◽  
C. L. Vanhoff ◽  
L. K. Flack
Keyword(s):  
Natural Enemies ◽  
New South ◽  
New South Wales ◽  
South Wales

scholarly journals The population dynamics of perennial chenopod shrubs in semi-arid western New South Wales.

1990 ◽  
Vol 12 (1) ◽  
pp. 29 ◽  
Author(s):  
DJ Eldridge
Keyword(s):  
Population Dynamics ◽  
Population Ecology ◽  
Arid Zone ◽  
Seedling Survival ◽  
New South ◽  
New South Wales ◽  
South Wales ◽  
Semi Arid

This thesis deals with some aspects of the population ecology of arid zone perennial chenopod shrubs. It examined the effects of grazing on the population dynamics of Atriplex vesicaria, Maireana astrotricha and Maireana pyramidata, the influence of weather on recruitment and survival of Atriplex vesicaria and the effects of various microtopographical features on seedling survival of Atriplex vesicaria.

The influence of grazing by cattle and sheep on the population dynamics of Bladder Saltbush (Atriplex Vesicaria) and white top (Danthonia caespitosa).

1980 ◽  
Vol 2 (2) ◽  
pp. 208 ◽  
Author(s):  
RD Graetz
Keyword(s):  
Population Dynamics ◽  
New South ◽  
New South Wales ◽  
Population Data ◽  
Plant Population ◽  
Rainfall Pattern ◽  
South Wales ◽  
A Site ◽  
Stocking Rates ◽  
Cattle And Sheep

Plant population data for the pass white-top (Danthonia caespitosa) and for bladder saltbush (Atriplex vesicaria) were collected for four years from a pasture continuously grazed by either cattle or sheep (at equivalent stocking rates) at a site near Booligal, New South Wales. During the four years of the experiment the cattle and sheep had different Impacts on the grass and scrub components of the pasture Sheep tended to deplete the numbers of pass plants far more than did cattle, whereas saltbush shrub numbers here little affected by either type of stock. The rainfall pattern experienced throughout the experiment had a far greater influence on the survival of both grass and shrub than did grazing.

Factors Influencing the Bacteriological Quality of Spa-Pool Waters in New South Wales (Australia)

1989 ◽  
Vol 21 (2) ◽  
pp. 141-145
Author(s):  
A. G. Bernard
Keyword(s):  
Water Quality ◽  
New South ◽  
New South Wales ◽  
Chlorine Disinfection ◽  
Bacteriological Quality ◽  
Department Of Health ◽  
Factors Influencing ◽  
South Wales ◽  
Principal Factors

The increasing popularity in the use of spa pools during the 1970's and 1980's and the accompanying incidents of folliculitis and ear infections caused by Pseudomonas aeruginosa associated with spa-pool use has necessitated the development of bacteriological and chemical guidelines for spa-pool water quality. The New South Wales (N.S.W.) Department of Health introduced a bacteriological standard for swimming pools and spa-pools in 1981 based on the findings of a series of surveys aimed at identifying the principal factors influencing the bacteriological quality of spa waters. Four surveys are summarised in this paper. The major findings described are the tenfold higher recovery of P. aeruginosa from spa-pools than from outdoor pools; the need for at least 2.0 milligrams per litre (mg/L) free chlorine residual in order to achieve reliable satisfactory water quality in spas compared with a requirement of 1.0mg/L to achieve the same quality in outdoor pools; the need to maintain pH below 8.0 in order to ensure efficient chlorine disinfection; the apparent inability of bromochlorodimethylhydantoin to adequately disinfect spas during heavy bather load periods; and the success of the Health Department's spa-pool operator education program which resulted in a 30% reduction in the incidence of bacteriologically unsatisfactory spa-pool waters in N.S.W. between 1980 and 1986.

Population ecology of the eastern pygmy-possum (Cercartetus nanus) in a montane woodland in southern New South Wales

2014 ◽  
Vol 36 (2) ◽  
pp. 212 ◽  
Author(s):  
Jamie M. Harris ◽  
Ross L. Goldingay ◽  
Lyndon O. Brooks
Keyword(s):  
Population Dynamics ◽  
Population Ecology ◽  
New South ◽  
Local Population ◽  
New South Wales ◽  
The Body ◽  
Floral Resources ◽  
Nectar Feeding ◽  
South Wales ◽  
Cercartetus Nanus

The population dynamics of nectar-feeding non-flying mammals are poorly documented. We investigated aspects of the population ecology of the eastern pygmy-possum (Cercartetus nanus) in southern New South Wales. We captured 65 individuals over a 4-year period during 5045 trap-nights and 1179 nest-box checks. The body mass of adult males (mean ± s.e. = 24.6 ± 1.0 g) was marginally not significantly different (P = 0.08) from that of non-parous adult females (28.2 ± 1.9 g). Females gave birth to a single litter each year of 3–4 young during February–May. No juveniles were detected in spring of any year. Mark–recapture modelling suggested that survival probability was constant over time (0.78) while recapture probability (0.04–0.81) varied with season and trap effort. The local population (estimated at ~20–25 individuals) underwent a regular seasonal variation in abundance, with a decline in spring coinciding with the cessation of flowering by Banksia. A population trough in spring has been observed elsewhere. This appears to represent some local migration from the study area, suggesting a strategy of high mobility to track floral resources. Conservation of this species will depend on a more detailed understanding of how flowering drives population dynamics.

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