Academic literature on the topic 'Red kangaroo Australia Reproduction'

Immunocontraception involves eliciting an immune response against eggs, sperm or hormones so that successful reproduction is prevented. Work in Australasia is aimed at European rabbits (Oryctolagus cuniculus), red foxes (Vulpes vulpes), house mice (Mus musculus), common brushtail possums (Trichosurus vulpecula), koalas (Phascolartcos cinereus) and kangaroos (Macropus spp.), with the vaccines involved all containing self antigens or their relatives. Two fundamental problems have been inadequately addressed in this research. The first problem is that it is difficult to obtain strong immune responses against self antigens and so the vaccines may be ineffective. Most published data on the effect of immunocontraceptives on reproduction involve the use of an adjuvant of which there are many kinds. The materials enhance the immune response greatly. The most frequently used is Freund?s adjuvant which can cause chronic suffering. Its use on wildlife will lead to very negative public perceptions. There has been no convincing demonstration that successful immunocontraception is possible with any method of vaccination likely to be used in the field, if success is defined as contraception of a proportion of the population high enough for management requirements. If it is assumed that success can be achieved, the second fundamental problem arises with two potential consequences. Even with adjuvant, a substantial minority of the vaccinated animals remains fertile. The first consequence is that since failure to be contracepted is likely to be in part genetic, there is likely to be rapid selection for these non-responders. The method will become ineffective in a few generations. The second problem is that the offspring of the animals which breed will have altered immune responses. Their capacities to respond to their own pathogens or to harbor pathogens of other species in the same ecosystem are likely to be changed. The presence of chlamydia in P. cinereus and bovine tuberculosis in New Zealand T. vulpecula means that responses to these pathogens would have to be studied in offspring of immunocontracepted parents to ensure that the offspring were not more susceptible to them. New Zealand intentions to put an immunocontraceptive into a T. vulpecula gut worm must be viewed with caution by Australia. The eggs of transgenic worms will be easily transplanted either accidentally or deliberately back into Australia, and so infect T. vulpecula in Australia.

The cDNA encoding the follicle stimulating hormone beta subunit (FSH-β) was isolated from a red kangaroo pituitary cDNA library by using a porcine probe and the nucleotide sequence for the coding region was determined. The highest degree of deduced amino acid sequence identity (91%) was observed between the red kangaroo and another marsupial, the brushtail possum (Trichosurus vulpecula), followed by eutherian species (76%, 75% and 74%, respectively, for pig, mouse and sheep). Based on the deduced red kangaroo FSH-β amino acid sequence, putative antigenic sites have been identified that may prove useful for studying the hormonal control of reproduction in marsupials.

Pastoralists frequently claim that attempts at range regeneration in arid and semi-arid areas are thwarted by kangaroos. This paper examines the possibility that the impact of kangaroo grazing is exacerbated by an influx of kangaroos onto regeneration sites. The amount of kangaroo dung in a 7500 ha paddock in arid Western Australia increased six-fold over a 15-month period following the removal of sheep. A similar influx was apparent in another destocked paddock that provided unusually high offtake of kangaroos by a commercial shooter. The amount of kangaroo dung remained relatively stable in a control paddock that was stocked. Some areas subject to cultivation and reseeding with native shrubs also showed increased amounts of kangaroo dung, indicating relatively intense kangaroo grazing. Radio-tracking of 46 kangaroos showed them to be mostly sedentary, suggesting that 'invading' kangaroos emerge from the local area. This conclusion is contrary to the widespread view that kangaroos migrate from distant locations. Thus, kangaroo control programs on sensitive areas are likely to be long-lasting because incursions are predominantly from local populations.

The red kangaroo (Macropus rufus) and the dingo (Canis dingo) are two of Australia's iconic mammals. Both are ingrained in the national psyche and well known internationally. For the red kangaroo, recognition has come despite the fact that the highest densities of the species occur well away from most of the human population. The dingo has achieved its status despite being present on the continent for perhaps as little as 3,000 years. This article considers the question of how, and why, these two animals became so elevated in the popular imagination and the scientific literature. It is a story of both the integers and consequences of scientific research, a story best told with a particular focus on the contribution made by one individual. Alan Newsome changed our understanding of the interactions between agriculture, introduced species and native wildlife, and was one of the first to understand the possibilities of enriching western science with Indigenous knowledge. He was a pioneer in explaining—particularly by reference to the red kangaroo in central Australia—the remarkable story of how Australian wildlife has adapted to survive some of the harshest conditions on the planet. His work across the landscape of the arid zone has had profound implications for management and conservation in Australia. This, then, is the story of three icons: the red kangaroo, the dingo and Alan Newsome.

The number of individuals in a wildlife population is often estimated and the estimates used for wildlife management. The scientific basis of published continental-scale estimates of individuals in Australia of feral cats and feral pigs is reviewed and contrasted with estimation of red kangaroo abundance and the usage of the estimates. We reviewed all papers on feral cats, feral pigs and red kangaroos found in a Web of Science search and in Australian Wildlife Research and Wildlife Research, and related Australian and overseas scientific and ‘grey’ literature. The estimated number of feral cats in Australia has often been repeated without rigorous evaluation of the origin of the estimate. We propose an origin. The number of feral pigs in Australia was estimated and since then has sometimes been quoted correctly and sometimes misquoted. In contrast, red kangaroo numbers in Australia have been estimated by more rigorous methods and the relevant literature demonstrates active refining and reviewing of estimation procedures and management usage. We propose four criteria for acceptable use of wildlife abundance estimates in wildlife management. The criteria are: use of appropriate statistical or mathematical analysis; precision estimated; original source cited; and age (current or out-of-date) of an estimate evaluated. The criteria are then used here to assess the strength of evidence of the abundance estimates and each has at least one deficiency (being out-of-date). We do know feral cats, feral pigs and red kangaroos occur in Australia but we do not know currently how many feral cats or feral pigs are in Australia. Our knowledge of red kangaroo abundance is stronger at the state than the continental scale, and is also out-of-date at the continental scale. We recommend greater consideration be given to whether abundance estimates at the continental scale are needed and to their use, and not misuse, in wildlife management.

We studied the impact of grazing by red kangaroos (Macropus rufus) on pasture biomass and species diversity over a 32-month period in destocked open shrubland in the Gascoyne region of Western Australia. Grazing significantly impeded the accumulation of annual and perennial grass biomass in a degraded perennial shrub community (Pc0.001 and P<0.05) and on denuded sites that were cultivated and reseeded with native shrubs (P<0.01 and Pc0.01). The accumulation of annual and perennial forb biomass was unaffected by kangaroo grazing. After 12 months, pasture species diversity was significantly greater on degraded perennial sites protected from kangaroo grazing (P<0.05). Commercial kangaroo shooting did not alleviate the impact of kangaroo grazing on grass accumulation (P<0.01). Unless more effective methods of kangaroo control are integrated with stock reductions, the recovery of degraded rangeland pastures is likely to be severely limited.

In this study we examined the utility of manipulating artificial waters as a means of managing total grazing pressure in semi-arid rangelands of eastern Australia. We tested the efficacy of 'Finlayson trough' exclosure technology at three locations, over two summers, in paddocks with red kangaroos (Macropus rufirs) and two species of grey kangaroo (M. giganteus and M. fuliginosus). We also examined the effect of closing off five waters on the distribution of feral goat grazing intensity at one study site. Generally, there were no apparent reductions in kangaroo and goat grazing intensity following 6-10 weeks of water exclosure, the exception being a minor reduction in red kangaroo grazing intensity at one location. We concluded that kangaroo and goat grazing pressure cannot be substantially reduced by simply closing off waters in and near paddocks for several months. Key words: kangaroos, water exclosure. feral goats, grazing pressure, paddock spelling

I studied aspects of the ecology of the Murray River turtle, Emydura macquarii, to determine the impact of the introduced red fox, Vulpes vulpes. The fox is one of Australia's worst vertebrate pests through its predation on livestock and native mammals, but their impact on reptilian communities is not known. I conducted a large-scale mark-recapture study to evaluate population growth of E. macquarii in the Albury region of the upper Murray River by determining growth, reproduction and survival. The study was conducted downstream of the first, and largest, impoundment on the Murray River, Lake Hume. Emydura macquarii predominantly inhabit the lagoons in the upper Murray River, as the mainstream and Lake are possibly too cool to maintain metabolic processes. They are easily captured in hoop traps and the use of live decoys maximises trap success. Over 2000 hatchling turtles were marked and released into two lagoons between January 1997 and January 1998. Growth of these individuals is rapid over the first few years but declines towards maturity, and is indeterminate after maturity. Although growth annuli are not well defined, even on young individuals, the von Bertalanffy model describes the growth of both male and female E. macquarii. Male turtles mature at 5-6 years and females mature at 10-12 years. Female turtles may maximise reproductive potential by delaying maturity and producing one relatively large clutch (mean = 21 eggs) per year, which is positively correlated with body size (PL). Although primarily related to body size, clutch size varies annually because of environmental conditions. If winter and summer rainfalls are below average and temperatures are above average, E. macquarii may reduce clutch size to increase the chance of the eggs surviving. Nesting predominantly occurs during the first major rain-bearing depression in November. Habitat variables, including distance from water, nearest nest, and tree, and soil type were measured for each nest to determine characteristics that attract predators. Nests close to the shoreline and trees are heavily preyed on, and nests constructed in sand are less likely to be destroyed by predators. Foxes detect nests through a combination of chemical cues from eggs and slight soil disturbances, whereas birds only destroy nests observed being constructed during the day. Female turtles alter nesting behaviour and construct nests much further away from water when foxes were removed and as a result, nests are less dense and away from trees. Thus in high predation risk areas, turtles minimise emergence and search times to reduce the risk of direct predation by foxes. Predation is reduced when nests are in lower densities and away from trees, because predators increase search efforts when nests are in higher densities and birds are more likely to destroy nests close to trees. Reproductive success is further reduced in high predation risk areas because more nests are constructed in sandy substrates where clutch success is reduced compared to incubation in more dense substrates. Where predators are a significant source of mortality, prey may use indirect methods, such as chemical recognition, to avoid encounters. Nesting turtles did not avoid areas where fox odour was present, suggesting that they assess predation pressure from foxes by other mechanisms, such as visual recognition. However, an innate response occurs to the odour of a once common predator on the Murray River, the eastern quoll (Dasyurus viverrinus), whereby turtles recognise and avoid nesting in areas where quoll odour is present. Therefore nesting turtles show a similar avoidance response to two different predators, using different mechanisms of detection. Similarly, predation risk may influence hatching times and nest emergence. The rate of embryonic development of E. macquarii may increase or eggs may hatch early so that the clutch hatches synchronously, thereby reducing the risk of predation through group emergence from the nest. Emydura macquarii reach densities of over 100 turtles.ha-1, with the majority of the population consisting of sexually mature individuals. Emydura macquarii has a Type III survival curve where mortality is extremely high in the egg stage (93% nest predation), remaining high over the hatchling stage (minimum survival rate- 10%), but decreasing rapidly throughout the juvenile stage (~70% juvenile survival). Adult survival is extremely high, with greater than 95% of adults surviving each year. Foxes through nest predation cause most mortality but a small proportion (~3%) of nesting adult females are killed by foxes each year. A removal program evaluated the impact of foxes. In 1996, fox numbers were monitored around four lagoons by spotlighting and non-toxic bait uptake. Foxes were removed from around two of the lagoons throughout 1997 and 1998, using spotlight shooting and 1080 bait poisoning. Fox numbers were continually monitored around all four lagoons during the study. Nest predation rates remained around 90% in all sites where foxes were present, but fell to less than 50% when foxes were removed. At the same time, predation on nesting female turtles was eliminated where foxes were removed. Demographic models using staged based survival schedules, together with growth and fecundity values for E. macquarii show a decline of 4% per year in these populations. Elasticity analyses shows that survival of adult female E. macquarii has the major influence on population stability and a reduction of nest predation alone is unlikely to address the population decline. Management options, such as reducing foxes prior to nesting around key lagoons, will stabilise the population decline, and eliminating foxes completely from certain areas with high dispersal potential, will promote recruitment of juvenile E. macquarii.

Assessment of trophic interactions between increasing populations of New Zealand fur seals (Arctocephalus forsteri) and fisheries in southern Australia is limited due to a lack of species specific demographic data and an understanding of the factors influencing population growth. To establish species specific demographic parameters a cross-sectional sample of New Zealand fur seal females (330) and males (100) were caught and individually-marked on Kangaroo Island, South Australia between 2000 and 2003. The seals were aged through examination of a postcanine tooth, which was removed from each animal to investigate age-specific life-history parameters. Annual formation of cementum layers was confirmed and accuracy in age estimation was determined by examination of teeth removed from individuals of known-age. Indirect methods of assessing reproductive maturity based on mammary teat characteristics indicated that females first gave birth between 4-8 years of age, with an average age at reproductive maturity of 5 years. Among reproductively mature females, age-specific reproductive rates increased rapidly between 4-7 years of age, reaching maximum rates of 70-81% between 8-13 years, and gradually decreased in older females. No females older than 22 years were recorded to pup. Age of first territory tenure in males ranged from 8-10 years. The oldest female and male were 25 and 19 years old, respectively. Post-weaning growth in females was monophasic, characterised by high growth rates in length and mass during the juvenile growth stage, followed by a gradual decline in growth rates after reproductive maturity. In contrast, growth in males was biphasic and displayed a secondary growth spurt in both length and mass, which coincided with sexual and social maturation, followed by a rapid decline in growth rates. Age-specific survival rates were high (0.823-0.953) among prime-age females (8-13 yrs of age) and declined in older females. Relative change in annual pup production was strongly correlated with reproductive rates of prime-age females and adult female survival between breeding seasons.

The red kangaroo is at the heart of Australia's ecological identity. It is Australia's largest terrestrial land mammal, the largest extant marsupial, and the only kangaroo truly restricted to Australia's arid interior. Almost nothing was known about the ecology of the red kangaroo when Alan Newsome began to study it in 1957. He discovered how droughts affect reproduction, why red kangaroos favour different habitats during droughts from those after rains, and that unprecedented explosions in red kangaroo numbers were caused by changes to the landscape wrought by graziers. Most importantly, he realised the possibilities of enriching western science with Indigenous knowledge, a feat recognised today as one of the greatest achievements of his career. First drafted in 1975 and now revised and prepared for publication by his son, The Red Kangaroo in Central Australia captures Alan's thoughts as a young ecologist working in Central Australia in the 1950s and 1960s. It will inspire a new generation of scientists to explore Australia's vast interior and study the extraordinary adaptations of its endemic mammals. It will also appeal to readers of other classics of Australian natural history, such as Francis Ratcliffe's Flying Fox and Drifting Sand and Harry Frith's The Mallee Fowl, The Bird that Builds an Incubator. Recipient of a 2017 Whitley Awards Certificate of Commendation for Pioneering Zoology