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.

Lamb mortality under three lambing systems

1974 ◽  
Vol 14 (70) ◽  
pp. 600 ◽  
Author(s):  
RN Tyrrell ◽  
JR Giles
Keyword(s):  
Environmental Conditions ◽  
New South ◽  
New South Wales ◽  
South Wales

Three systems of lambing management were compared at Trangie in Central Western New South Wales. A supervised system involving daily drifting of ewes through a series of small paddocks was first compared with an unsupervised system in which ewes were set-stocked in a single large paddock (A) and later, an unsupervised system in which ewes were set-stocked in sub-flocks according to their expected date of lambing (B). Lamb loss associated with the management of marking and mulesing proved to be an important factor in the comparison. The introduction of unsupervised system (B) was associated with a reduction in losses after marking compared with the supervised system. Lamb loss prior to marking was lowest in the supervised system. Of the three systems, unsupervised system (B) is considered the most suitable for areas in which environmental conditions during lambing are not harsh.

Habitat Utilization by Sympatric Red Kangaroos Macropus-Rufus, and Western Grey Kangaroos Macropus-Fuliginosus, in Western New-South-Wales

1988 ◽  
Vol 15 (4) ◽  
pp. 413 ◽  
Author(s):  
D Priddel
Keyword(s):  
Temporal Change ◽  
New South ◽  
New South Wales ◽  
Aerial Survey ◽  
Habitat Utilization ◽  
South Wales ◽  
Macropus Rufus

Habitat utilisation by sympatric red kangaroos, Macropus rufus, and western grey kangaroos, M. fuliginosus, was monitored by aerial survey. Red kangaroos used floodplain and sandplain with equal intensity. Western grey kangaroos favoured floodplain and utilised woodland on both landforms relatively more than did red kangaroos. Movements of kangaroos between sandplain and floodplain paralleled changes in pasture condition. Red kangaroos responded to pasture growth, moving to sandplain immediately after rain. Western greys followed up to 3 months later, the increase in use of sandplain being weakly correlated (r = 0.70) to an increase in pasture biomass. There was no evidence of any temporal change in use of either woodland or open plain by either species.

Habitat Selection by Sex, Age and Reproductive Class in the Red Kangaroo, Macropus rufus, in Western New South Wales

1981 ◽  
Vol 8 (3) ◽  
pp. 465 ◽  
Author(s):  
CN Johnson ◽  
PG Bayliss
Keyword(s):  
Habitat Selection ◽  
National Park ◽  
Mating Systems ◽  
New South ◽  
New South Wales ◽  
Vegetation Types ◽  
Red Kangaroo ◽  
South Wales ◽  
Macropus Rufus ◽  
Lactating Females

The kangaroo populations of Kinchega National Park respond differently to shifts in pasture productivity, red kangaroos Macropus rufus being mobile and unevenly distributed with respect to soil and vegetation types, by comparison with the more evenly dispersed western grey kangaroos M. fuliginosus and the sedentary and localized euros M, robustus erubescens. Red kangaroo population classes tend to be differentially distributed, so that large males and heavily lactating females predominate on the seasonally preferred pastures, while other classes tend to predominate elsewhere. This finding has several implications for the management of red kangaroos and for our understanding of their resource ecology and mating systems.

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 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.

scholarly journals Beach safety: can drones provide a platform for sighting sharks?

2019 ◽  
Vol 46 (8) ◽  
pp. 701 ◽  
Author(s):  
Paul A. Butcher ◽  
Toby P. Piddocke ◽  
Andrew P. Colefax ◽  
Brent Hoade ◽  
Victor M. Peddemors ◽  
...  
Keyword(s):  
Water Depth ◽  
Environmental Conditions ◽  
New South ◽  
Marine Ecosystem ◽  
New South Wales ◽  
Cost Effective ◽  
Independent Observer ◽  
South Wales ◽  
User Groups ◽  
Shark Attacks

Abstract ContextA series of unprovoked shark attacks on New South Wales (Australia) beaches between 2013 and 2015 triggered an investigation of new and emerging technologies for protecting bathers. Traditionally, bather protection has included several methods for shark capture, detection and/or deterrence but has often relied on environmentally damaging techniques. Heightened environmental awareness, including the important role of sharks in the marine ecosystem, demands new techniques for protection from shark attack. Recent advances in drone-related technologies have enabled the possibility of real-time shark detection and alerting. AimTo determine the reliability of drones to detect shark analogues in the water across a range of environmental conditions experienced on New South Wales beaches. MethodsA standard multirotor drone (DJI Inspire 1) was used to detect shark analogues as a proxy during flights at 0900, 1200 and 1500 hours over a 3-week period. The 27 flights encompassed a range of environmental conditions, including wind speed (2–30.0kmh−1), turbidity (0.4–6.4m), cloud cover (0–100%), glare (0–100%), seas (0.4–1.4m), swells (1.4–2.5m) and sea state (Beaufort Scale 1–5 Bf). Key resultsDetection rates of the shark analogues over the 27 flights were significantly higher for the independent observer conducting post-flight video analysis (50%) than for the drone pilot (38%) (Wald P=0.04). Water depth and turbidity significantly impaired detection of analogues (Wald P=0.04). Specifically, at a set depth of 2m below the water surface, very few analogues were seen by the observer or pilot when water turbidity reduced visibility to less than 1.5m. Similarly, when water visibility was greater than 1.5m, the detection rate was negatively related to water depth. Conclusions The present study demonstrates that drones can fly under most environmental conditions and would be a cost-effective bather protection tool for a range of user groups. ImplicationsThe most effective use of drones would occur during light winds and in shallow clear water. Although poor water visibility may restrict detection, sharks spend large amounts of time near the surface, therefore providing a practical tool for detection in most conditions.

Movement of Kangaroos After a Fire in Mallee Woodland.

1985 ◽  
Vol 12 (3) ◽  
pp. 349 ◽  
Author(s):  
G Caughley ◽  
B Brown ◽  
J Noble
Keyword(s):  
Plant Growth ◽  
New South ◽  
New South Wales ◽  
Burned Area ◽  
Aerial Surveys ◽  
South Wales ◽  
Adequate Food ◽  
Macropus Rufus ◽  
Stimulate Plant Growth ◽  
Grazing Sheep

Experimental burning of mallee (Eucalyptus spp.) and shrub vegetation has been done in New South Wales to stimulate plant growth for grazing sheep and cattle. In March 1984 fires were started by an aerial ignition technique in a 'paddock' of 116 km2 and a study was made, by aerial surveys, of movements of kangaroos (Macropus rufus and M. fuliginosus) into the area. Such movements would detract from the benefit to grazing stock. It was found that on this occasion the burned area did not attract kangaroos, apparently because good winter rains gave adequate food for them elsewhere. It is suggested that burning for grazing is likely to be most beneficial where winter rains are most predictable, i.e. inside the mallee zone.

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