Journal articles on the topic 'Eastern grey kangaroo Australia Reproduction'
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Descovich, Kris, Andrew Tribe, Ian J. McDonald, and Clive J. C. Phillips. "The eastern grey kangaroo: current management and future directions." Wildlife Research 43, no. 7 (2016): 576. http://dx.doi.org/10.1071/wr16027.
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The eastern grey kangaroo is a common and iconic species of Australia. Its specialised behaviour and reproduction have evolved as adaptations to the Australian environment, allowing the species to survive and flourish, despite wide climatic and seasonal variations in habitat. Across its range, the eastern grey kangaroo is harvested and subjected to population management for a variety of reasons, including localised over-abundance, livestock competition, crop grazing, native habitat conservation, animal welfare and direct threats to human safety. Population management of kangaroos is most commonly undertaken by shooting, although other methods such as reproductive control, translocation and repellents may also contribute successfully to management. Kangaroo harvesting and population control are controversial and divisive, because the kangaroo is perceived as both a national icon and as a pest species. Although a limited number of surveys have been undertaken on attitudes towards kangaroos and their management, the socio-political aspects affecting these issues are yet to be systematically investigated. Within this review we discuss the relevance of culture and language to species management and conservation, as well as the importance of scrutiny of stakeholder perceptions, motivations and values. Future directions should examine human dimensions that influence kangaroo-management decisions and conservation. The following three key aspects are recommended as research and management priorities: (1) experimental determination of whether gaps exist between actual and perceived impacts of kangaroo populations, (2) empirical investigation of how stakeholder language, culture, identity and values influence perceptions of kangaroos and their management, and (3) where population control is determined to be necessary, an incorporation of stakeholder differences within decision making to ensure best outcomes for both species conservation and population management.
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Herbert, C. A., T. E. Trigg, and D. W. Cooper. "Fertility control in female eastern grey kangaroos using the GnRH agonist deslorelin. 1. Effects on reproduction." Wildlife Research 33, no. 1 (2006): 41. http://dx.doi.org/10.1071/wr04113.
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Eastern grey kangaroos are widespread on the east coast of Australia and frequently reach high densities in reserves and parkland near urban areas. Management of these populations is highly contentious and non-lethal fertility-control technologies are sought as an alternative option to manage population size. This study evaluated the potential of slow-release gonadotrophin-releasing hormone agonist (deslorelin) implants to inhibit reproduction in female kangaroos. Deslorelin treatment effectively inhibited reproduction in adult females for periods of 559 ± 111 days (n = 6) and 651 ± 21 days (n = 5) after administration of one or two 10-mg implants respectively. Animals treated with the lower dosage tended to resume breeding earlier than those that received a total of 20 mg of deslorelin (minimum duration of 18 months). Deslorelin treatment had no effect on blastocyst reactivation in a single treated female and repeat treatment had no negative side-effects. This study has demonstrated that slow-release deslorelin implants can successfully inhibit reproduction for extended periods in the female eastern grey kangaroos. This approach may have potential application in reproductive management of problem kangaroo populations.
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Wilson, Michelle E., and Graeme Coulson. "Comparative efficacy of levonorgestrel and deslorelin contraceptive implants in free-ranging eastern grey kangaroos (Macropus giganteus)." Wildlife Research 43, no. 3 (2016): 212. http://dx.doi.org/10.1071/wr15176.
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Context Fertility control of females with levonorgestrel or deslorelin implants shows promise for managing populations of overabundant eastern grey kangaroos (Macropus giganteus). Although these implants have been tested separately in captive and free-ranging kangaroos, there has been no direct comparison under equivalent field conditions. Aims We investigated the long-term efficacy of levonorgestrel and deslorelin implants, together with the cost of treatment, ease of administration, and the welfare of the animals, in a side-by-side trial under realistic management conditions. Methods We captured 65 adult female kangaroos over 11 days at a golf course in Anglesea, Victoria, Australia. We assigned each female to one of the following three experimental groups: levonorgestrel (210 mg, n = 18), deslorelin (9.4 mg, n = 24) or procedural control (n = 23). We monitored reproductive success for 8 years, by observing young in the pouch in winter and spring. Key results Natural fertility was high; in most years, less than 20% of control females failed to reproduce. For deslorelin-treated females, the odds of failing to reproduce were four times higher than for the control group; for levonorgestrel-treated females, these odds were 74 times higher. Deslorelin was ineffective after 3 years, whereas levonorgestrel was effective for at least 5 years. Conclusions Levonorgestrel was markedly superior in efficacy, as shown by a stronger contraceptive effect persisting for longer. In other respects, the two implants were comparable, being similar in cost and ease of delivery, and equally safe. Implications Only levonorgestrel implants fulfill their promise for non-lethal, long-term control of kangaroo populations. Deslorelin implants cannot be recommended for this purpose.
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Arnold, GW, DE Steven, and JR Weeldenberg. "Comparative ecology of western grey kangaroos (Macropus fulginosus) and euros (M. robustus erubescens) in Durokoppin Nature Reserve, isolated in the central wheatbelt of Western Australia." Wildlife Research 21, no. 3 (1994): 307. http://dx.doi.org/10.1071/wr9940307.
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The populations of western grey kangaroos (Macropus fuliginosus) and euros (M. robustus erubescens) in a 1196-ha area of native vegetation in the central wheatbelt of Western Australia were studied over six years (1985-91). The area was isolated from other remnants of native vegetation by at least 1.4 km. Captures were made periodically throughout each year and the animals weighed and measured. In all, 152 animals were captured (83 euros and 69 western grey kangaroos). The data for each sex and species were assigned to 'seasons' (February-July or August-January) and assessments made of body condition. The weights and tail circumstances, adjusted for individual size by regression on leg length, were higher for western grey kangaroos but not for euros in August-January. Euro males varied significantly in weight from year to year; euro females and grey males and females did not. Too few grey females were captured to analyse seasonality of reproduction. The estimated birth dates of 68 euro pouch young were distributed equally throughout the study period. There were approximately equal numbers of each species in an estimate made in 1988 from a helicopter survey, with a total (� s.e.) of 191�29 kangaroos. The mean faecal pellet counts on 42 Tied transects of 100 m2 did not differ significantly over the period 1985-88. These counts showed that the overall use of the different vegetation types varied by a factor of two. Heaths had the highest pellet counts and open mallee or woodland the least, with Allocasuarina-dominated shrublands being intermediate. Spotlight surveys around the reserve boundary showed a highly significant difference in distribution of the two species. This was confirmed by analysis of the home ranges of 13 radio-collared individuals. Euros showed a strong preference for areas of York gum-wandoo-jam woodland with a herbaceous ground layer and areas with tall Allocasuarina or dense heath. In contrast, the western grey kangaroos preferred the heathlands and open woodlands without a herbaceous ground cover. The sex ratios of the whole populations seen in spotlight searches was 0.72 : 1.00 (males: females) for western grey kangaroos and 0.81 : 1.00 for euros. Both differ significantly from parity. There was a higher proportion of female euros amongst the animals seen in the western part of the reserve than in the eastern part. These populations relied mainly on the resources of the reserve. The average number of kangaroos seen on adjacent farmland on any one night varied from 3.6 in 1986 to 13.5 in 1991. A significantly higher proportion of males of both species were seen on farmland.
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Brunton, Elizabeth A., Sanjeev K. Srivastava, David S. Schoeman, and Scott Burnett. "Quantifying trends and predictors of decline in eastern grey kangaroo (Macropus giganteus) populations in a rapidly urbanising landscape." Pacific Conservation Biology 24, no. 1 (2018): 63. http://dx.doi.org/10.1071/pc17034.
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Human population growth and the resultant expansion of urban landscapes are drivers of biodiversity loss globally. Impacts of urbanisation on wildlife are not well understood, although the importance of preserving biodiversity in urban areas is widely recognised. The eastern grey kangaroo (Macropus giganteus), a common species of large macropod, can be found in high densities in many urban landscapes across Australia. South East Queensland is a subtropical region of Australia that has experienced high rates of urban expansion. Human population growth in the region has resulted in widespread changes to the landscape and much of the eastern grey kangaroo’s natural habitat has been modified. Declines in kangaroo populations have been anecdotally reported; however, the impact of urbanisation on kangaroo populations has not been quantified. This study used a modelling approach, collecting data from the community, and private and government organisations to: (1) map the current distribution of eastern grey kangaroos; (2) quantify trends in kangaroo abundance; and (3) identify anthropogenic drivers of changes in kangaroo abundance in the region. Of the kangaroo populations identified, 42% were reported to have undergone an overall decline in abundance since 2000. Higher human population growth rate and smaller area remaining under natural land use were predictors of kangaroo population declines. Further kangaroo declines can be anticipated in the region, particularly in areas with projected human population growth rates over 80% for the next decade. This study emphasises the importance of integrated urban development over large spatial extents to mitigate impacts of urbanisation on terrestrial mammals.
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Pople, A. R., S. C. Cairns, N. Menke, and N. Payne. "Estimating the abundance of eastern grey kangaroos (Macropus giganteus) in south-eastern New South Wales, Australia." Wildlife Research 33, no. 2 (2006): 93. http://dx.doi.org/10.1071/wr05021.
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To provide an estimate of kangaroo numbers for harvest management, a survey was designed for an area of 29 500 km2 encompassing the agricultural and grazing lands of the Braidwood, Cooma, Goulburn, Gundagai and Yass Rural Lands Protection Board (RLPB) districts in south-east New South Wales. An aerial survey using a helicopter was considered more efficient than ground survey because of the size of the area, relatively high relief and dense tree cover, and the need for regular monitoring. Tree cover and landscape relief was used to stratify the five RLPB districts into areas of probable high, medium and low kangaroo density. Kangaroo density estimated from helicopter surveys conducted in the Northern Tablelands of New South Wales was used to suggest densities and thereby allocate survey effort in each stratum. A survey comprising 735 km of transect line was conducted in winter 2003 with a target precision of 20%. The survey returned an estimate of 286 600 ± 32 300 eastern grey kangaroos for the whole of the proposed south-east New South Wales kangaroo-management zone. In 2004, a trial harvest of slightly less than 15% of this estimate was taken. Success of the trial will be determined by the impact of harvesting on the population’s dynamics, by landholder and industry participation, and by the capacity to monitor population size, harvest offtake and compliance with regulations.
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Coulson, Graeme, Christopher D. Nave, Geoff Shaw, and Marilyn B. Renfree. "Long-term efficacy of levonorgestrel implants for fertility control of eastern grey kangaroos (Macropus giganteus)." Wildlife Research 35, no. 6 (2008): 520. http://dx.doi.org/10.1071/wr07133.
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Overabundant populations of kangaroos pose substantial management problems in small parks on the fringe of urban areas in Australia. Translocation is impractical and culling is often not publicly acceptable, but fertility control offers an acceptable alternative. One potential contraceptive is levonorgestrel, which provides effective long-term contraception in women, and prevents births in some marsupials for up to five years. We evaluated the long-term efficacy of levonorgestrel in free-ranging eastern grey kangaroos (M. giganteus) at two sites in Victoria, Australia. We trapped 25 adult females at one site (Portland Aluminium), treating 18 with two subcutaneous 70-mg levonorgestrel implants and seven with control (inert) implants. We darted 25 adult females at the other site (Woodlands Historic Park), treating all with two 70-mg levonorgestrel implants. We monitored the reproductive status of the kangaroos, as indicated by the obvious presence of a pouch young, in spring each year for up to seven years. In the first three years at Portland, 81–86% of levonorgestrel-treated females were infertile, compared with 12–29% in the control group, but the effectiveness of fertility control declined over time. At this site, the proportions of treated females breeding in the fourth, fifth, sixth and seventh years of the trial were 36%, 50%, 67% and 100% respectively. Fecundity at Woodlands was similar. Although this protocol achieved fertility control for several years, it was likely that more than one treatment or a higher dose rate would be required for effective fertility control in this long-lived species.
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Cairns, S. C., G. W. Lollback, and N. Payne. "Design of aerial surveys for population estimation and the management of macropods in the Northern Tablelands of New South Wales, Australia." Wildlife Research 35, no. 4 (2008): 331. http://dx.doi.org/10.1071/wr07079.
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As part of a kangaroo management program, eastern grey kangaroos (Macropus giganteus) and common wallaroos (M. robustus robustus) are harvested from three kangaroo management zones in north-eastern New South Wales, Australia. To set sustainable harvest quotas, it is necessary to obtain reasonably accurate estimates of the sizes of the populations of these two species of macropod. Recently, this has been done on two occasions using helicopter line-transect surveys. For the most recent of these surveys, conducted in 2004, each management zone was subdivided into three strata of increasing kangaroo density and the surveys were designed in relation to this stratification using an automated survey design algorithm. The results of the surveys were that eastern grey kangaroo densities were estimated as 8.11 ± 1.81 km–2 in the Glen Innes zone, 10.23 ± 2.41 km–2 in the Armidale zone and 4.82 ± 0.87 km–2 in the Upper Hunter zone. Wallaroo densities for these three zones were 3.06 ± 0.73 km–2, 5.68 ± 3.45 km–2 and 4.40 ± 1.01 km–2 respectively. The wallaroo densities were determined by multiplying the initial estimated densities by a correction factor of 1.85. Across the three kangaroo management zones, eastern grey kangaroo densities did not change in any significant way between the two surveys. This was also the case for wallaroos in the Glen Innes and Armidale zones. Wallaroo density in the Upper Hunter zone, however, increased significantly between the two surveys. Over a decade before these surveys were conducted, a series of ground surveys using walked line-transect sampling were undertaken. The density estimates derived from the helicopter surveys proved to be broadly comparable to those derived from the ground surveys, suggesting that conducting helicopter line-transect surveys designed using the method deployed here is effective in producing population estimates for the purpose of kangaroo management.
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Ritchie, EG. "An extension to the known range of the eastern grey kangaroo Macropus giganteus on Cape York Peninsula." Australian Mammalogy 27, no. 2 (2005): 225. http://dx.doi.org/10.1071/am05225.
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THE eastern grey kangaroo (Macropus giganteus) is one of Australia?s widest-ranging large macropodids, occurring in open forests, woodlands, subalpine woodland, farmland, and semi-arid regions throughout most of eastern Australia (Menkhorst and Knight 2001). However current general accounts (e.g., Poole 1995, Menkhorst and Knight 2001) regard M. giganteus as being absent from the northern Cape York Peninsula.
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McLeod, Steven R., Neal Finch, Glenn Wallace, and Anthony R. Pople. "Assessing the spatial and temporal organization of Red Kangaroo, Western Grey Kangaroo and Eastern Grey Kangaroo populations in eastern Australia using multivariate autoregressive state‐space models." Ecological Management & Restoration 22, S1 (November 2021): 106–23. http://dx.doi.org/10.1111/emr.12488.
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Hinds, LA, and CH Tyndale-Biscoe. "The effects of bromocriptine on lactation and subsequent reproduction in grey kangaroos, Macropus fuliginosus and Macropus giganteus." Reproduction, Fertility and Development 6, no. 6 (1994): 705. http://dx.doi.org/10.1071/rd9940705.
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Both species of grey kangaroo were tested to determine whether a single exposure to bromocriptine in mid winter will terminate lactation, and whether females that cease to lactate will return to oestrus immediately and give birth early, or at the next summer breeding season. In Experiment 1, 11 lactating western grey kangaroos (Macropus fuliginosus) received injections either of saline (n = 2) or of bromocriptine at dose rates of 0.2, 1.0 or 5.0 mg kg-1 bodyweight (n = 3 per dose). Pouch young of females treated with the highest dose of bromocriptine showed either retarded growth or no growth, but they subsequently survived. In Experiment 2, lactating western (n = 12) and eastern grey kangaroos (M. giganteus) (n = 14) received a single intramuscular injection of saline or approximately 2 mg kg-1 or 4 mg kg-1 Parlodel LA (a long-acting form of bromocriptine) and their young were weighed. Within 3 weeks, the young of all 19 females treated with Parlodel LA had lost weight and 17 had died, whereas only one young, which had not lost weight, was lost from the seven control females. The western grey females did not give birth until the normal summer breeding season but the eastern grey females gave birth 2-4 months early. It is concluded that bromocriptine has potential for the humane control of grey kangaroo populations.
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Barker, R. D., and G. Caughley. "Distribution and abundance of kangaroos (Marsupialia: Macropodidae) at the time of European contact: South Australia." Australian Mammalogy 17, no. 1 (1994): 73. http://dx.doi.org/10.1071/am94008.
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Historical records, and the names of animals within Aboriginal languages, were analysed to compare the distribution and density of kangaroos at European contact with those of today. We gave up this attempt for the Eastern Grey Kangaroo, Macropus giganteus, presently restricted to the extreme south-east of the state, because it was never differentiated historically from the Southern Grey Kangaroo, M. fuliginosus, which occurs right across the southern portion of the state. The historical distribution of the latter species, and of the Red Kangaroo, M. rufus, seems to have been similar to their distribution today. Past densities are difficult to extract from historical records and are not sufficiently reliable to justify comparison with present densities. We note however an apparent increase in density of 'kangaroos' in the mid-1800s.
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Brunton, Elizabeth A., Sanjeev K. Srivastava, and Scott Burnett. "Spatial ecology of an urban eastern grey kangaroo (Macropus giganteus) population: local decline driven by kangaroo–vehicle collisions." Wildlife Research 45, no. 8 (2018): 685. http://dx.doi.org/10.1071/wr18077.
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Context As urban landscapes proliferate globally, the need for research into urban wildlife interactions is magnified. The eastern grey kangaroo (Macropus giganteus) is a widespread species commonly involved in wildlife–vehicle collisions in urban areas in Australia. Despite the many urban kangaroo populations and associated conflicts with human activities, few studies have examined how eastern grey kangaroos interact with, and are affected by, the urban matrix. Aims The present study aimed to quantify kangaroo demography, movements, habitat utilisation and exposure to risks during a period of intensive urban development in a rapidly changing suburb located in a region undergoing high urban growth rates. Methods We utilised foot-based census surveys, global positioning system (GPS) collars, direct observations and reports of wildlife mortality between 2014 and 2016. Geographical information systems (GIS) were used to integrate GPS-tracking data with spatial layers, to quantify kangaroo movements and habitat utilisation. Key results The kangaroo population underwent a steep decline and kangaroo–vehicle collisions were the main source of mortality (73%) during the study period. Kangaroos were regularly exposed to the risk of injury, with roads intersecting many parts of their home range. Kangaroos showed positive habitat selection both for lawn and forest habitats and kangaroo movement and presence at the study site were influenced by high-quality forage and cover. Conclusions The present research has highlighted that despite areas of suitable habitat remaining, road-kill was a major contributor to localised kangaroo-population decline. We showed that habitat preferences of eastern grey kangaroos in this urban area were consistent with those in natural landscapes. Implications The present study is the first to implicate kangaroo–vehicle collisions as the major factor in population decline in kangaroos. These findings can be utilised to guide design and placement of kangaroo–vehicle collision mitigation and assist in planning of urban areas, particularly where kangaroo populations are in decline. Local extirpation of urban kangaroo populations would be greatly reduced by incorporating site-specific kangaroo habitat preferences and existing patterns of kangaroo habitat use in infrastructure planning. The study has contributed to our understanding of the effects of roads on urban wildlife in general and highlighted the importance of landscape permeability.
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Hume, Georgina, Elizabeth Brunton, and Scott Burnett. "Eastern Grey Kangaroo (Macropus giganteus) Vigilance Behaviour Varies between Human-Modified and Natural Environments." Animals 9, no. 8 (July 27, 2019): 494. http://dx.doi.org/10.3390/ani9080494.
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Rapid increases in urban land use extent across the globe are creating challenges for many wildlife species. Urban landscapes present a novel environment for many species, yet our understanding of wildlife behavioural adaptations to urban environments is still poor. This study compared the vigilance behaviour of a large mammal in response to urbanisation at a landscape level. Here, we investigate urban (n = 12) and non-urban (n = 12) populations of kangaroos in two regions of Australia, and the relationship between kangaroo vigilance and urbanisation. We used a linear modelling approach to determine whether anti-predator vigilance and the number of vigilant acts performed were influenced by land use type (i.e., urban or non-urban), human population densities, kangaroo demographics, and environmental factors. Kangaroo behaviour differed between the two study regions; kangaroo vigilance was higher in urban than non-urban sites in the southern region, which also had the highest human population densities, however no effect of land use was found in the northern region. Season and sex influenced the vigilance levels across both regions, with higher levels seen in winter and female kangaroos. This study is the first to compare urban and non-urban vigilance of large mammals at a landscape level and provide novel insights into behavioural adaptations of large mammals to urban environments.
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Bender, Helena. "Effectiveness of the eastern grey kangaroo foot thump for deterring conspecifics." Wildlife Research 32, no. 7 (2005): 649. http://dx.doi.org/10.1071/wr04091.
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Overabundant wild populations of herbivores often present challenges to primary industry, competing with stock, and damaging crops and property. Eastern grey kangaroos (Macropus giganteus) are one of seven macropodid species that are considered a problem in agriculture in Australia. Most deterrent devices available commercially use sounds that do not occur in nature (i.e. artificial sounds), which often have a short-lived or no effect on the target species, whereas trials with biologically significant sounds are often more effective and provide greater resistance to habituation. I used a playback trial of an eastern grey kangaroo foot thump, a biologically significant signal that is given in response to a predator and is usually followed by flight. I determined its effectiveness compared with a recording of background noise (control) for deterring kangaroos over a seven-week period. Kangaroos significantly increased their vigilance levels in response to the foot thump, but not in response to the control signal. Just over 60% of kangaroos took flight in response to the foot thump and the control signals, but more kangaroos took flight in the first 3 s when the foot thump was played. The foot thump shows potential as a deterrent of eastern grey kangaroos for primary industry, and is less likely to suffer from habituation because it is a natural sound.
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Wilson, Michelle E., Graeme Coulson, Geoff Shaw, and Marilyn B. Renfree. "Deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus): mechanism of action and contraceptive efficacy." Wildlife Research 40, no. 5 (2013): 403. http://dx.doi.org/10.1071/wr13050.
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Context Fertility control offers a non-lethal management technique for iconic yet overabundant wildlife. Slow-release hormonal implants containing deslorelin show promise for managing free-ranging populations, particularly in peri-urban reserves, but most studies have been limited to captivity. Aims We investigated the efficacy and mechanism of deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus) under realistic management conditions. Methods We assigned females to a deslorelin (9.4 mg, n = 53) or placebo (n = 56) group at three peri-urban sites in Victoria, Australia, and monitored reproductive success for 3 years by observing young in the pouch. We tested the plasma LH response of control and treated females to exogenous GnRH, and compared the size of ovarian follicles between the two groups. Key results Deslorelin implants reduced fertility at all three sites. No deslorelin-treated females bred in Year 1 at Anglesea and Serendip versus 42% and 44% of control females respectively. At Plenty Gorge, 60% of deslorelin-treated females bred in Year 1 versus 100% of control females. In Year 2, between 11% and 39% of the treated females bred versus between 82% and 100% of control females at all sites. The contraceptive efficacy reduced by Year 3 when between 43% and 57% of the treated females bred versus between 85% and 100% of controls. A GnRH challenge elicited higher plasma LH concentrations in control than in treated females, and unlike untreated females, treated females lacked ovarian follicles >2 mm. Conclusions Deslorelin implants reduced fertility in free-ranging female eastern grey kangaroos over three successive breeding seasons. Chronic exposure to deslorelin desensitised the pituitary gland to GnRH and suppressed follicular development, but did not inhibit the development of a blastocyst, pregnancy or lactation in at least some females that had conceived before treatment. Implications Effective population management using deslorelin implants will require females to be re-treated on multiple occasions because the contraceptive effect lasts only a portion of their reproductive life. This would be practical only at sites where kangaroos are relatively easy to capture. The timing of treatment is also important in a species that undergoes embryonic diapause, particularly at sites providing high-quality habitat.
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Power, Michelle L., Nicholas C. Sangster, Martin B. Slade, and Duncan A. Veal. "Patterns of Cryptosporidium Oocyst Shedding by Eastern Grey Kangaroos Inhabiting an Australian Watershed." Applied and Environmental Microbiology 71, no. 10 (October 2005): 6159–64. http://dx.doi.org/10.1128/aem.71.10.6159-6164.2005.
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ABSTRACT The occurrence of Cryptosporidium oocysts in feces from a population of wild eastern grey kangaroos inhabiting a protected watershed in Sydney, Australia, was investigated. Over a 2-year period, Cryptosporidium oocysts were detected in 239 of the 3,557 (6.7%) eastern grey kangaroo fecal samples tested by using a combined immunomagnetic separation and flow cytometric technique. The prevalence of Cryptosporidium in this host population was estimated to range from 0.32% to 28.5%, with peaks occurring during the autumn months. Oocyst shedding intensity ranged from below 20 oocysts/g feces to 2.0 × 106 oocysts/g feces, and shedding did not appear to be associated with diarrhea. Although morphologically similar to the human-infective Cryptosporidium hominis and the Cryptosporidium parvum “bovine” genotype oocysts, the oocysts isolated from kangaroo feces were identified as the Cryptosporidium “marsupial” genotype I or “marsupial” genotype II. Kangaroos are the predominant large mammal inhabiting Australian watersheds and are potentially a significant source of Cryptosporidium contamination of drinking water reservoirs. However, this host population was predominantly shedding the marsupial-derived genotypes, which to date have been identified only in marsupial host species.
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Freudenberger, D., and RB Hacker. "The Effect of Temporary Closure of Watering Points on Grazing Intensity of Red and Grey Kangaroos With Related Observations on Feral Goats." Rangeland Journal 19, no. 2 (1997): 157. http://dx.doi.org/10.1071/rj9970157.
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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
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Brandimarti, Maquel E., Rachael Gray, Fabiola R. O. Silva, and Catherine A. Herbert. "Kangaroos at maximum capacity: health assessment of free-ranging eastern grey kangaroos on a coastal headland." Journal of Mammalogy 102, no. 3 (March 30, 2021): 837–51. http://dx.doi.org/10.1093/jmammal/gyab022.
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Abstract Sprawling urban development is fragmenting the landscape and native wildlife habitats on the Australian east coast. The impact of this rapid urbanization on wildlife health is largely unknown. This study surveyed the health of a high-density (5.4 individuals per ha) population of eastern grey kangaroos (Macropus giganteus) affected by urban encroachment and prolonged drought. Blood parameters (hematological and serum protein), trace element and heavy metal concentrations, and parasite counts (fecal worm egg counts, ticks, and mites) are reported for a sample of ≤ 54 kangaroos at Look at Me Now Headland, New South Wales, Australia. These parameters were compared to lower density kangaroo populations from other sites in New South Wales. We found the health and welfare of this population to be severely compromised, with nonregenerative anemia and nutritional deficiencies evident. Our results indicate that high-density kangaroo populations isolated by urban encroachment are at significant health risk. To prevent further decline in this population’s health, we discuss management strategies that could be employed, concurrent with ongoing health and disease monitoring, to mitigate the poor health outcomes in this population. We conclude that it is essential to retain habitat connectivity when altering land use in areas with resident kangaroo populations if managers are to maintain healthy populations.
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Coulson, G. "The Effect of Drought on Road Mortality of Macropods." Wildlife Research 16, no. 1 (1989): 79. http://dx.doi.org/10.1071/wr9890079.
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Road-kills of eastern grey kangaroos, Macropus giganteus, and swamp wallabies, Wallabia bicolor, were monitored during and after the severe 1981-83 drought in central Victoria, Australia. These were compared with a survey of the same area prior to the drought. The frequency of road-kills of both species during the drought was higher than pre-drought and post-drought levels, and over 9 years the seasonal frequency of kangaroo road-kills was inversely related to the rainfall of the previous season. Road-kills of kangaroos were predominantly males, and almost half were juveniles.
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Garnick, S., J. Di Stefano, M. A. Elgar, and G. Coulson. "Do body size, diet type or residence time explain habitat use in a vertebrate herbivore community?" Australian Journal of Zoology 64, no. 2 (2016): 91. http://dx.doi.org/10.1071/zo15061.
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Many theories attempt to explain patterns of community organisation among large herbivores. We explored the role of body size, diet type and residence time on habitat use in a community comprising four metatherians (western grey kangaroo, Macropus fuliginosus; eastern grey kangaroo, M. giganteus; red-necked wallaby, Notamacropus rufogriseus; swamp wallaby, Wallabia bicolor) and two eutherians (red deer, Cervus elaphus; European rabbit, Oryctolagus cuniculus) in south-eastern Australia. We used camera traps to estimate habitat occupancy, quantified habitat specialisation using relative entropy, and ran regressions using percentage grass consumed, log(mass) and log(time at site) as predictor variables and relative entropy as the response. If body size influenced habitat use, we predicted smaller species would occupy fewer habitats. If diet type influenced habitat use, we predicted intermediate feeders would use more habitats. If the time that a species had been present at a site predicted community organisation, newer species would use more habitats. None of these theories explained habitat use in our community. Red deer used a narrower range of habitats than expected, perhaps due to the poor suitability of habitats available in the Grampians. While interactions between our hypotheses are likely to be important, the body size model deserves further attention in this community.
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Coulson, Graeme. "Male Bias in Road-kills of Macropods." Wildlife Research 24, no. 1 (1997): 21. http://dx.doi.org/10.1071/wr96004.
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I determined the sex of a total of 251 road-kills of six macropod species in southern Australia over a 13-year period. There was a significant bias towards males in five species, ranging from 65 to 92% males, but there was no difference from parity in the red kangaroo, Macropus rufus. Male eastern grey kangaroos, M. giganteus, and male western grey kangaroos, M. fuliginosus, probably behave in ways that expose them to vehicles more than females. Male-biased road-kills of swamp wallabies, Wallabia bicolor, may reflect skewed population sex ratios. There are insufficient data on the behaviour and population structure of the red-necked wallaby, M. rufogriseus, and rufous-bellied pademelon, Thylogale billardierii, to determine which explanation is responsible for male-biased road mortality in these species.
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Neaves, Linda E., Kyall R. Zenger, Robert I. T. Prince, and Mark D. B. Eldridge. "Paternally inherited genetic markers reveal new insights into genetic structuring within Macropus fuliginosus and hybridisation with sympatric Macropus giganteus." Australian Journal of Zoology 61, no. 1 (2013): 58. http://dx.doi.org/10.1071/zo12087.
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There are several aspects of biology in which the contribution of males and females is unequal. In these instances the examination of Y chromosome markers may be used to elucidate male-specific attributes. Here, male dispersal patterns and genetic structuring were examined using four Y-microsatellite loci in 186 male western grey kangaroos, Macropus fuliginosus, from throughout the species’ trans-continental distribution. In addition, 52 male grey kangaroos were examined to investigate hybridisation between M. fuliginosus and the eastern grey kangaroo, Macropus giganteus, in their region of sympatry in eastern Australia. Detected Y chromosome diversity was low, resulting from low effective male population size due to skewed sex ratios and a polygynous mating system. As expected, male dispersal was high across the range. However, the Lake Torrens–Flinders Ranges region appears to have significantly restricted male movement between eastern and central/western Australia. There was little evidence to suggest that other barriers (Nullarbor Plain and Swan River Valley) previously identified by nuclear and mitochondrial DNA marker studies restrict male movement. Hence, the admixture events previously identified may be associated with high male dispersal. Within the region of sympatry between M. fuliginosus and M. giganteus in eastern Australia, four M. giganteus individuals were found to possess M. fuliginosus Y-haplotypes. These results confirm the occurrence of hybridisation between male M. fuliginosus and female M. giganteus. Additionally, the introgression of M. fuliginosus Y-haplotypes into M. giganteus populations indicates that at least some male hybrids are fertile, despite evidence to the contrary from captive studies. This study has provided insights into the male contribution to population history, structure and hybridisation in M. fuliginosus, which were not predicted by comparisons between biparentally and maternally inherited markers. This highlights the importance of direct examination of the Y chromosome to provide novel insights into male-mediated processes, especially where the contribution of the sexes may differ.
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Balland, Jeff, Catherine A. Herbert, Justin A. Welbergen, and John M. Martin. "Habitat selection in a peri-urban area by a large mammal indicates a low potential for human–wildlife conflict." Wildlife Research 47, no. 5 (2020): 381. http://dx.doi.org/10.1071/wr19234.
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Abstract ContextIn Australia, various species of macropods (family Macropodidae) are known to occur within peri-urban areas, where they can be a source of human–wildlife conflict. Some species, such as the eastern grey kangaroo (Macropus giganteus), have received considerable research attention over the past few years following demands from land managers for evidence-based management guidelines; however, the ecology of other macropod species found in peri-urban areas, such as the eastern wallaroo (Osphranter robustus robustus), remains poorly understood. AimsThe aims were to determine the home range of male and female eastern wallaroos and assess habitat selection in order to define whether wallaroos in a peri-urban environment should be viewed as thriving (‘matrix-occupying’), persisting (‘matrix-sensitive’) or struggling (‘urban-sensitive’). MethodsHome range and habitat use of six adult male, five adult female and one subadult male eastern wallaroo were investigated using GPS telemetry between October 2017 and May 2018 in the south-west of Sydney. Key resultsHome ranges (mean±s.e.) of males (63.1±10.2ha) were significantly larger than those of females (31.1±3.3ha). Every adult wallaroo had highly overlapping monthly home ranges, indicating strong site fidelity in all individuals. Eastern wallaroos selected habitats based on vegetation composition during the night and canopy cover during the day. Grassland and open native woodlands were preferred during foraging activities at night. By contrast, human-modified habitats, including hard surfaces and lawns, were avoided at all times by all individuals. ConclusionThe results indicate that eastern wallaroos avoid human-modified features in the landscape, so they could be viewed as persisting (‘matrix-sensitive’) in peri-urban areas. ImplicationsCompared with matrix-occupying macropods, such as the eastern grey kangaroo, the eastern wallaroo is less likely to cause human–wildlife conflicts – a result of its avoidance of human-modified habitat. Land-use planning, involving green corridors linking remnant vegetation, should be implemented as part of urban planning to enable the persistence of diverse mammal populations in urban areas, particularly matrix-sensitive species.
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Glass, Ruth, David M. Forsyth, Graeme Coulson, and Marco Festa-Bianchet. "Precision, accuracy and bias of walked line-transect distance sampling to estimate eastern grey kangaroo population size." Wildlife Research 42, no. 8 (2015): 633. http://dx.doi.org/10.1071/wr15029.
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Context Distance sampling is widely used to estimate the size of wildlife populations, including kangaroos. However, the performance of distance-sampling abundance estimates has seldom been evaluated for wild mammal populations of known size. Aims We evaluated the precision, accuracy, bias and interval coverage of abundance estimates from walked line-transect sampling, a commonly used distance-sampling method, for a marked free-ranging population of eastern grey kangaroos (Macropus giganteus) at Yanakie Isthmus, Wilsons Promontory National Park, south-eastern Australia. Methods In each of two study periods (November 2012 and May 2013) we first determined the true size of the uniquely marked kangaroo population by conducting 10 intensive searches of the study area. We then conducted distance sampling along six systematically spaced line transects. We walked each transect four times in November 2012 and seven times in May 2013. Data were analysed using Program DISTANCE. Key results Our intensive searches revealed that 141 and 124 collared kangaroos were present in the study area in November 2012 and May 2013, respectively. When transects were walked four or more times (i.e. ≥400 observations), maximum precision (coefficient of variation; CV of ~13%) was achieved in both survey periods. Walking transects twice (i.e. ~200 observations) produced abundance estimates with CVs of <20% in each study period. The accuracy (root mean square error) of abundance estimates varied from 1 to 13 (November 2012) and from 3 to 28 (May 2013). Bias ranged from −9% to +23%, but stabilised at between −1% and −9% when transects were walked four or more times in each study period. The 95% confidence intervals for the abundance estimates always included the true population size. Conclusions Our results indicated that walked line-transect distance sampling is a precise and accurate method for estimating eastern grey kangaroo abundance. The small negative biases that occurred when sample sizes were large were likely to be due to some animals moving outside the study area. Implications Provided that the key design elements and assumptions are met, estimates of kangaroo abundance from walked line-transect distance sampling should have good precision (CV < 20%) and minimal (<10%) bias.
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Juillard, Loic Quentin, and Daniel Ramp. "The Impacts of Drought on the Health and Demography of Eastern Grey Kangaroos." Animals 12, no. 3 (January 21, 2022): 256. http://dx.doi.org/10.3390/ani12030256.
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Extreme climatic events such as droughts and floods are expected to become more intense and severe under climate change, especially in the southern and eastern parts of Australia. We aimed to quantify the relationship between body condition scores (BCS), demography, activity rate, and parasitic infections of eastern grey kangaroos on a large conservation property under different climate extremes by employing camera traps established at artificial water points (AWPs). The survey period included a severe drought, broken by a significant flooding event. Climatic and environmental conditions were documented using remotely sensed indices of moisture availability and vegetation productivity. These conditions were found to affect all health and population parameters measured. BCS, juvenile proportions, and sex ratios were most correlated with 6-month lags in climatic conditions, while the activity rate of kangaroos at AWPs was most correlated with vegetation productivity. Ticks were mostly found on individuals with a poorer BCS, while the concentration of parasitic eggs in feces was higher in autumn than in spring. Our study offers a glimpse into some of the environmental drivers of eastern grey kangaroo populations and their health, information that may become increasingly important in today’s climate. It further emphasizes the importance of this knowledge for wildlife conservation efforts appropriate to managing the impact of climate change alongside other threats.
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Woodward, R., M. E. Herberstein, and C. A. Herbert. "Fertility control in female eastern grey kangaroos using the GnRH agonist deslorelin. 2. Effects on behaviour." Wildlife Research 33, no. 1 (2006): 47. http://dx.doi.org/10.1071/wr04114.
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In recent years fertility control has been proposed as an ethically acceptable alternative to lethal control techniques when managing overabundant kangaroo populations. A promising non-steroidal, non-immunological approach to contraception in female kangaroos involves the use of slow-release implants containing the gonadotrophin-releasing hormone (GnRH) agonist deslorelin. The practicality of using deslorelin implants as a management option is dependant on its effective inhibition of reproduction without negative physical or behavioural side-effects. This study investigated the behavioural effects of deslorelin implants in female eastern grey kangaroos. Treatment had no detectable effects on crepuscular activity. Alterations in the frequency of sexual interactions were observed in deslorelin-treated females, with a behavioural oestrus induced ~3 days after combined removal of pouch young and deslorelin administration. Copulation was observed during this early oestrous period, but conception was not achieved and pouch young were not observed in any treated females. Control females gave birth within 69.6 ± 10.4 days (mean ± s.e.m., n = 9) of placebo implant administration. The first births observed in treated animals were on Days 510, 637 and 643 after treatment. The remaining seven treated animals had not bred by the end of the study, a period of 647 days.
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Lee, E., U. Klöcker, DB Croft, and D. Ramp. "Kangaroo-vehicle collisions in Australia's sheep rangelands, during and following drought periods." Australian Mammalogy 26, no. 2 (2004): 215. http://dx.doi.org/10.1071/am04215.
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The effects of roads on wildlife behaviour and ecological function are poorly known in arid Australia. The most obvious impact is roadkill from wildlife-vehicle collisions. Therefore we collected statistics on kangaroo-vehicle collisions, investigated the causal factors of these collisions, and related roadkill mortality to the population structure, size and distribution of four kangaroo species in two intensive six month studies during and following drought. The research was conducted along a 21.2 km sealed section of the Silver City Highway between Broken Hill and Tibooburra that passes through the University of New South Wales (NSW) Arid Zone Research Station at ‘Fowlers Gap’ in north-western NSW. The rate of roadkill was higher during drought (20.8 roadkills month-1) than non-drought (2.6 roadkills month-1). Affected species were red kangaroos (Macropus rufus), euros (Macropus robustus erubescens), western grey kangaroos (Macropus fuliginosus) and eastern grey kangaroos (Macropus giganteus). During drought, M. fuliginosus and M. giganteus were killed in lower proportions than their proportion in the source population, otherwise species were killed in proportion to their density along the road. There were no sex biases but male M. r. erubescens were much more likely to be beside the road than females and thus were killed more often during drought. The majority of roadkills were young individuals around 2 years old. Curves and stockraces along the road significantly increased the likelihood of roadkills. Likewise the frequency of roadkills was a function of the kangaroo population density along the road, night time traffic volume, low rainfall and higher vegetation cover and greenness along the road relative to surrounding areas. We evaluate the relationships between these causal factors and kangaroovehicle collisions, and discuss the possible effects of these collisions on kangaroo population structure under drought and post-drought conditions.
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Davis, Naomi E., Julian Di Stefano, Graeme Coulson, Jim Whelan, and John Wright. "Vegetation management influences habitat use by mammalian herbivores in shrub-encroached grassy woodland." Wildlife Research 43, no. 5 (2016): 438. http://dx.doi.org/10.1071/wr15218.
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Context Restoration of disturbed vegetation communities commonly involves altering vegetation composition and structure, attributes that can influence the suitability of habitat for fauna. Feedbacks may occur whereby changes to the vegetation affect mammalian herbivores, and unintended changes may prevent managers from achieving conservation goals. Aims To understand how vegetation management affects habitat use by five mammalian herbivores, namely eastern grey kangaroo (Macropus giganteus), swamp wallaby (Wallabia bicolor), common wombat (Vombatus ursinus), European rabbit (Oryctolagus cuniculus) and hog deer (Axis porcinus). Methods A management experiment (mechanical slashing of the encroaching shrub Leptospermum laevigatum) at Wilsons Promontory National Park, Australia, created slashed swales in addition to untreated dune and scrub woodland. In each vegetation stratum, we estimated the cover of L. laevigatum and quantified herbivore abundance by counting the standing crop of faecal pellets. Key results Relative to untreated vegetation, mechanical slashing of L. laevigatum substantially reduced cover of this species above 200 cm, but increased its cover below 30 cm. On the basis of faecal-pellet counts, multispecies use of managed and unmanaged parts of the landscape differed substantially, with the differences principally driven by higher abundance of European rabbits and eastern grey kangaroos at slashed sites. Conclusions The responses of three grazing species (kangaroo, rabbits and wombats) to vegetation management were predicted well by prior knowledge of diet and habitat preferences. This was not the case for the browser (swamp wallaby), nor for the grazer that consumes substantial amounts of browse in the study area (hog deer), and additional knowledge of the processes underlying their responses to vegetation change is required. Implications Our findings highlighted that vegetation management can influence herbivore abundances in the managed system. An improved understanding of these associations will allow vegetation management plans to incorporate herbivore responses.
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Lethbridge, Mark, Michael Stead, and Cameron Wells. "Estimating kangaroo density by aerial survey: a comparison of thermal cameras with human observers." Wildlife Research 46, no. 8 (2019): 639. http://dx.doi.org/10.1071/wr18122.
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Abstract ContextAerial surveys provide valuable information about the population status and distribution of many native and pest vertebrate species. They are vital for evidence-based monitoring, budget planning and setting management targets. Despite aircraft running costs, they remain one of the most cost-effective ways to capture distribution and abundance data over a broad area. In Australia, annual surveys of large macropods are undertaken in several states to inform management, and in some jurisdictions, to help set commercial kangaroo harvest quotas. Improvements in the cost efficiencies of these surveys are continually sought. Aerial thermal imaging techniques are increasingly being tested for wildlife surveys, but to date no studies have directly compared population data derived from thermal imaging with data collected by human observers during the same flight. AimsDuring an aerial survey of western grey kangaroos (Macropus fuliginosus), eastern grey kangaroos (M. giganteus) and red kangaroos (Osphranter rufus) across the state of Victoria, Australia, the objective was to conduct a direct comparison of the effectiveness of thermal camera technology and human observers for estimating kangaroo populations from aerial surveys. MethodsA thermal camera was mounted alongside an aerial observer on one side of the aircraft for a total of 1360km of transect lines. All thermal footage was reviewed manually. Population density estimates and distance sampling models were compared with human observer counts. Key resultsOverall, the kangaroo density estimates obtained from the thermal camera data were around 30% higher than estimates derived from aerial observer counts. This difference was greater in wooded habitats. Conversely, human-derived counts were greater in open habitats, possibly due to interference from sunlight and flushing. It was not possible to distinguish between species of macropod in the thermal imagery. ConclusionsThermal survey techniques require refining, but the results of the present study suggest that with careful selection of time of day for surveys, more accurate population estimates may be possible than with conventional aerial surveys. ImplicationsConventional aerial surveys may be underestimating animal populations in some habitats. Further studies that directly compare the performance of aerial observers and thermal imaging are required across a range of species and habitats.
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Davis, Naomi E., and Graeme Coulson. "Habitat-specific and season-specific faecal pellet decay rates for five mammalian herbivores in south-eastern Australia." Australian Mammalogy 38, no. 1 (2016): 105. http://dx.doi.org/10.1071/am15007.
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The accuracy of population abundance estimates of mammalian herbivores from faecal pellet counts is potentially affected by pellet decay. We collected fresh pellet groups from hog deer (Axis porcinus), European rabbit (Oryctolagus cuniculus), eastern grey kangaroo (Macropus giganteus), swamp wallaby (Wallabia bicolor) and common wombat (Vombatus ursinus) (n = 300 per species) at Wilsons Promontory National Park, Victoria, Australia. We deposited five pellet groups per species per month within each of five vegetation types in the park, then monitored pellet group decay over 24 months. We demonstrate that age estimation of pellet groups was inaccurate and is unlikely to improve the efficiency of pellet counts. We present habitat- and species-specific estimates of pellet and pellet group decay using two measures: decay rate (the proportion of pellets surviving per unit of time); and mean time to decay. We explain how our data can be used to optimise faecal pellet count design, and to improve the accuracy of both indices and estimates of abundance from pellet counts. The variability observed in the decay of pellet groups among vegetation types, and for species among seasons, suggests that caution should be used if applying pellet decay rates over long time-frames or to locations with differing environmental conditions.
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Coulson, G., A. Poiani, and CD Nave. "A modified draw-string trap for capture of kangaroos at fences." Australian Mammalogy 25, no. 2 (2003): 177. http://dx.doi.org/10.1071/am03177.
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We modified an earlier design of a draw-string trap to capture free-ranging eastern grey kangaroos, Macropus giganteus, at Portland Aluminium, Victoria, Australia. The trap consisted of a tunnel of netting suspended from a metal frame erected at a narrow gateway in a fence, which was constructed where kangaroos had established runways between paddocks and shelterbelts. We set up five traps on different fences and operated them from a hide 20 m away. A team of 2 ? 6 people drove kangaroos from the paddocks into cover, and the reverse. When a target individual entered a trap, we closed the netting at each end with hand-operated drawstrings, thereby restraining the kangaroo for examination and treatment. We captured 28 individuals a total of 59 times, and encountered few problems. The technique has potential for use with kangaroos and other species that habitually push under fences.
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Riquelme, Linda, Libby Rumpff, David H. Duncan, and Peter A. Vesk. "Understanding the spatiotemporal dynamics of understorey biomass in semi-arid woodlands of south-eastern Australia." Rangeland Journal 44, no. 1 (April 16, 2022): 47–59. http://dx.doi.org/10.1071/rj21060.
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When managing grazing pressure for conservation, understanding forage dynamics is essential. In south-eastern Australia, ongoing grazing is inhibiting regeneration in several semi-arid woodland communities. Western grey kangaroos (Macropus fuliginosus (Desmarest, 1817)) have been identified as a key component of total grazing pressure. They are thought to switch from grass to lower-quality browse, including tree seedlings, when grass biomass falls below 400 kg ha−1. One static threshold may not adequately capture the spatial and temporal hazard associated with kangaroo grazing, and this study aimed to explore how grassy biomass varies across a case-study landscape. Understorey biomass and species composition data were collected in the field on seven occasions between December 2016 and May 2019. We used Generalised Linear Mixed Models (GLMMs) to describe the influence of environmental and herbivory variables on total (live and dead) understorey, live understorey, and grass (live and dead) biomass. Canopy cover showed the strongest influence on understorey biomass, with more biomass found in open sites than in woodland. Understorey biomass levels were lowest in summer and autumn. Grass biomass, in particular, fell below the 400 kg ha−1 forage-switch threshold in wooded areas during this time. We anticipate that an increased understanding of understorey biomass dynamics will inform managers as to when and where to focus management efforts to promote regeneration and sustained recovery of these semi-arid woodlands. Results of this study suggest that conducting management efforts before the summer/autumn decline in understorey biomass, particularly in woodlands, is critical in reducing the browsing risk to seedlings.
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Trembath, Dane F., Simon Fearn, and Eivind Andreas Baste Undheim. "Natural history of the slaty grey snake (Stegonotus cucullatus) (Serpentes:Colubridae) from tropical north Queensland, Australia." Australian Journal of Zoology 57, no. 2 (2009): 119. http://dx.doi.org/10.1071/zo08091.
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Slaty grey snakes (Stegonotus cucullatus) are medium to large members of the Colubridae that are common throughout the eastern and northern tropics of Australia. Although intensive field studies have been conducted on populations in the Northern Territory for over 10 years, no ecological data have been presented on free-ranging specimens of populations inhabiting tropical north Queensland. During a 10-year period we collected opportunistic data on 120 free-ranging specimens from the seasonally Wet Tropics in north Queensland. These snakes provided data on body sizes, activity times, food habits and reproduction. Male S. cucullatus were larger than females and had larger heads. More snakes were found during the warmer, humid parts of the year (wet season). S. cucullatus ate a wide range of vertebrate prey, including reptile eggs that were obtained seasonally. Females produced one clutch per year, and no relationship was found between maternal snout–vent length and clutch size.
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Davis, Naomi E., Ian R. Gordon, and Graeme Coulson. "The influence of evolutionary history and body size on partitioning of habitat resources by mammalian herbivores in south-eastern Australia." Australian Journal of Zoology 65, no. 4 (2017): 226. http://dx.doi.org/10.1071/zo16075.
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Habitat use is the most common dimension along which sympatric species partition resources to reduce competition. We conducted faecal pellet counts at Wilsons Promontory National Park, Victoria, to examine habitat use by an assemblage of mammalian herbivores with disparate evolutionary histories and varying body size: introduced European rabbit (Oryctolagus cuniculus) and hog deer (Axis porcinus), and native eastern grey kangaroo (Macropus giganteus), swamp wallaby (Wallabia bicolor) and common wombat (Vombatus ursinus). Overlap in habitat use was low between four pairs of species, suggesting spatial partitioning of resources to reduce the potential for interspecific competition. More generally, however, overlap in habitat use was high, particularly between native and introduced grazers. These results indicate the potential for competition if resources were limiting and suggest that assemblages of species with independent evolutionary histories have inherently less resource partitioning to facilitate coexistence than assemblages of species with common evolutionary histories. Despite evidence of high overlap in habitat use between native and introduced species at a broad scale, and variation in the competitive ability of species, coexistence was likely facilitated by niche complementarity, including temporal and fine-scale partitioning of spatial resources. There was no relationship between body size and the diversity of habitats used. In contemporary assemblages of native and introduced species, evolutionary history is likely to have a strong influence on resource partitioning.
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Arundel, JH, KJ Dempster, KE Harrigan, and R. Black. "Epidemiological Observations on the Helminth Parasites of Macropus Giganteus Shaw in Victoria." Wildlife Research 17, no. 1 (1990): 39. http://dx.doi.org/10.1071/wr9900039.
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An epidemiological study of the nematode parasites of the eastern grey kangaroo (M. giganteus) was made in an enclosed reserve north of Melbourne, Victoria, Australia. Adult and juvenile kangaroos were collected at approximately 6-weekly intervals and blood, faeces and the entire gastrointestinal tract was obtained. The nematodes present were Globocephaloides trifidospicularis, Rugopharynx australis, R. rosemariae, Pharyngostrongylus kappa, Cloacina spp., Strongyloides sp., Macropostrongylus baylisi, Paramacropostrongylus toraliformis, Alocostoma clelandi, Labiostrongylus spp., Macroponema comani and Macropoxyuris. The majority of nematodes had a seasonal fluctuation. Acquisition commenced in late summer and reached a peak in midwinter before declining in spring. G. trifidospicularis caused considerable mortality in juvenile kangaroos and there was a strong relationship between rising numbers of this species and falling plasma protein, haemoglobin concentration and haematocrit values. This species can cause heavy mortality in juvenile kangaroos in enclosed populations when winter feed is depleted and when the small animals with no fat reserves experience maximum cold stress. Other parasites present included Progamotaenia ewersi, P. festiva, P. macropodis, Triplotaenia fimbriata, T. undosa, Eimeria wilcanniensis, E. macropodis, E. hestermani and E. marsupialum.
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Pillans, Brad, and Robert Bourman. "Mid Pleistocene arid shift in southern Australia, dated by magnetostratigraphy." Soil Research 39, no. 1 (2001): 89. http://dx.doi.org/10.1071/sr99089.
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In coastal sections at Hallett Cove and Sellicks Beach, south of Adelaide, and at Redbanks section on Kangaroo Island, the Brunhes/Matuyama polarity transition (780 ka) is identified in the strongly oxide-mottled Ochre Cove Formation. At all 3 sections, the Ochre Cove Formation is overlain by a calcareous grey-green aeolian clay, called Ngaltinga Clay, which in turn is overlain by calcareous sediments of the Taringa and Christies Beach Formations. The marked change from an oxide-dominated weathering regime to a carbonate-dominated weathering regime, estimated to have occurred at about 500–600 ka, is interpreted as a major arid shift in regional climates. Similar arid shifts are known from Lake Bungunnia in the Murray Basin and Lake Lefroy in southern Western Australia, where changes from lacustrine clays to evaporites and dune sediments are estimated to have occurred between 400 and 700 ka, and about 500 ka, respectively. An increase in aeolian dust accession in south-eastern Australia, consistent with increased aridity in the interior source area, occurred after 780 ka, and was probably coeval with increased dust input to Tasman Sea sediments since 350 ka. Between 600 and 900 ka, oxygen isotope fluctuations in deep-sea cores showed a pronounced change in frequency, from a 40 ka (obliquity dominated) to a 100 ka (eccentricity dominated) pattern. At the same time, glacial-interglacial amplitudes increased, with a marked enrichment of glacial d18O values consistent with larger continental based ice-sheets. Colder global temperatures, and lower sea levels during glacials, may have played a part in the mid Pleistocene arid shift recorded in southern Australia. Associated variations in the strength of the warm Leeuwin Current may also have affected regional rainfall patterns in southern Australia.
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Brunton, Elizabeth A., Javier X. Leon, and Scott E. Burnett. "Evaluating the Efficacy and Optimal Deployment of Thermal Infrared and True-Colour Imaging When Using Drones for Monitoring Kangaroos." Drones 4, no. 2 (May 27, 2020): 20. http://dx.doi.org/10.3390/drones4020020.
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Advances in drone technology have given rise to much interest in the use of drone-mounted thermal imagery in wildlife monitoring. This research tested the feasibility of monitoring large mammals in an urban environment and investigated the influence of drone flight parameters and environmental conditions on their successful detection using thermal infrared (TIR) and true-colour (RGB) imagery. We conducted 18 drone flights at different altitudes on the Sunshine Coast, Queensland, Australia. Eastern grey kangaroos (Macropus giganteus) were detected from TIR (n=39) and RGB orthomosaics (n=33) using manual image interpretation. Factors that predicted the detection of kangaroos from drone images were identified using unbiased recursive partitioning. Drone-mounted imagery achieved an overall 73.2% detection success rate using TIR imagery and 67.2% using RGB imagery when compared to on-ground counts of kangaroos. We showed that the successful detection of kangaroos using TIR images was influenced by vegetation type, whereas detection using RGB images was influenced by vegetation type, time of day that the drone was deployed, and weather conditions. Kangaroo detection was highest in grasslands, and kangaroos were not successfully detected in shrublands. Drone-mounted TIR and RGB imagery are effective at detecting large mammals in urban and peri-urban environments.
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Woinarski, J. C. Z., J. C. McCosker, G. Gordon, B. Lawrie, C. James, J. Augusteyn, L. Slater, and T. Danvers. "Monitoring change in the vertebrate fauna of central Queensland, Australia, over a period of broad-scale vegetation clearance, 1973—2002." Wildlife Research 33, no. 4 (2006): 263. http://dx.doi.org/10.1071/wr03110.
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This study reports change in the bird, mammal and amphibian fauna of the Emerald district, central Queensland, as detected from comparison of an inventory study undertaken in 1973–76, with a resurvey undertaken in 2001–02. Over this period, the region was subjected to unusually high rates of vegetation clearance, with the extent of native vegetation declining from 87% to 41%. In Australia, and elsewhere, there are remarkably few such long-term longitudinal studies, and particularly so for those that sample the same sites using identical procedures, and for those undertaken in a region of such dramatic environmental change. The ability to detect change from this dataset is constrained by the relatively small number of survey sites (24–45 survey sites, depending upon the taxonomic group considered). The interpretation of change is also affected by very different climatic conditions between the baseline and resurvey. Higher rainfall in the baseline survey period contributed to the most evident change, a major reduction in the number of waterbirds. However, even with waterbirds excluded, there was a significant change in the bird assemblage across the set of survey sites between the two periods. There were significant increases for a number of typically grassland birds (e.g. red-backed fairy-wren (Malurus melanocephalus), brown quail (Coturnix ypsilophora)) and significant decreases for a range of typically forest or woodland birds (e.g. grey shrike-thrush (Colluricincla harmonica), spiny-cheeked honeyeater (Acanthagenys rufogularis), striped honeyeater (Plectorhyncha lanceolata), grey fantail (Rhipidura fuliginosa)). These changes were largely maintained even when the dataset was restricted to only those sites that remained uncleared: that is, changes were evident not only across the changing landscape as a whole but there were also significant (consequential) changes at uncleared sites. Most of the native mammal species that were recorded sufficiently often to test for change showed a pattern of decline. Again, for some species (pale field-rat (Rattus tunneyi), greater glider (Petauroides volans) and eastern grey kangaroo (Macropus giganteus)), this decline occurred even within uncleared woodland sites. The most notable change in the frog fauna was the major increase in the exotic cane toad (Bufo marinus), but there were also significant declines for two native frog species. These results suggest a general trajectory of decline in distinctive woodland species, and their broad-scale replacement by more commensal species (weedy generalists favoured by human modification of the landscape).
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Dawson, Terence J., Kirsten J. McTavish, Adam J. Munn, and Joanne Holloway. "Water use and the thermoregulatory behaviour of kangaroos in arid regions: insights into the colonisation of arid rangelands in Australia by the Eastern Grey Kangaroo (Macropus giganteus)." Journal of Comparative Physiology B 176, no. 1 (October 6, 2005): 45–53. http://dx.doi.org/10.1007/s00360-005-0030-2.
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Webster, C., M. Massaro, D. R. Michael, D. Bambrick, J. L. Riley, and D. G. Nimmo. "Native reptiles alter their foraging in the presence of the olfactory cues of invasive mammalian predators." Royal Society Open Science 5, no. 10 (October 2018): 180136. http://dx.doi.org/10.1098/rsos.180136.
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Invasive mammalian predators are linked to terrestrial vertebrate extinctions worldwide. Prey naïveté may explain the large impact invasive predators have on native prey; prey may fail to detect and react appropriately to the cues of novel predators, which results in high levels of depredation. In Australia, the feral cat ( Felis catus ) and the red fox ( Vulpes vulpes ) are implicated in more than 30 animal extinctions and the naïveté of native prey is often used to explain this high extinction rate. Reptiles are one group of animals that are heavily preyed upon by F. catus and V. vulpes . However, very few studies have examined whether reptiles are naive to their cues. In this study, we examine the ability of two native reptile species ( Morethia boulengeri and Christinus marmoratus ) to detect and distinguish between the chemical cues of two invasive predators ( V. vulpes and F. catus ) and three native predators (spotted-tailed quoll, Dasyurus maculatus; dingo, Canis lupus dingo ; eastern brown snake, Pseudonaja textilis ), as well as two non-predator controls (eastern grey kangaroo, Macropus giganteus and water). We conducted experiments to quantify the effects of predator scents on lizard foraging (the amount of food eaten) during 1 h trials within Y-maze arenas. We found both study species reduced the amount they consumed when exposed to predator scents—both native and invasive—indicating that these species are not naive to invasive predators. An evolved generalized predator-recognition system, rapid evolution or learned behaviour could each explain the lack of naïveté in some native Australian reptiles towards invasive predators.
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Hampton, Jordan O., and David M. Forsyth. "An assessment of animal welfare for the culling of peri-urban kangaroos." Wildlife Research 43, no. 3 (2016): 261. http://dx.doi.org/10.1071/wr16023.
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Context Shooting is used to reduce the abundance of kangaroo (Macropus sp.) populations in many peri-urban areas in Australia, but there is uncertainty surrounding the animal welfare outcomes of this practice. Aim We assessed the animal welfare outcomes of night shooting for peri-urban eastern grey kangaroos (Macropus giganteus). We quantified the duration of stress for: (1) shot animals; (2) euthanased pouch young; and (3) other animals in the same social group. Methods An independent observer collected thermal imagery data, enabling four key animal welfare parameters to be quantified: instantaneous death rate, median time to death, wounding rate and flight duration of conspecifics. The duration between pouch removal and insensibility was recorded for pouch young. Post-mortem data were recorded to confirm the location and extent of pathology from shooting. Key results Of the 136 kangaroos that were shot at, two were missed. The wounding rate was zero, with a 98% instantaneous death rate. The median time to death for the three animals not killed instantaneously was 12 s. For pouch young considered sentient, the median stress time was 4 s. Kaplan–Meier survival analysis revealed that the median flight duration of conspecifics was 5 s. Conclusions Our results indicate that night shooting produces a very short duration of stress to shot kangaroos, their pouch young and their conspecifics. Implications When compared to other wildlife shooting methods, night shooting is a humane method for culling peri-urban kangaroos.
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Green-Barber, Jai M., and Julie M. Old. "What influences road mortality rates of eastern grey kangaroos in a semi-rural area?" BMC Zoology 4, no. 1 (December 2019). http://dx.doi.org/10.1186/s40850-019-0047-8.
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Abstract Background Roads have major ecological impacts on wildlife. Vehicle collisions most frequently impact large herbivores due to their larger home range compared to smaller animals, and higher population density compared to carnivores. Kangaroos (Macropus spp.) account for a large proportion of reported wildlife vehicle collisions that occur in N S W, Australia. We aimed to evaluate what influenced road mortality of eastern grey kangaroos (Macropus giganteus) in a temperate rural/suburban region. The location of roadkilled kangaroos found on or near two 1 km stretches of road in Richmond NSW was recorded throughout 2014 and 2015. Weather and moon phase data were recorded for the date of each roadkilled kangaroo. Transects were setup on both roads, and multiple road and landscape features, including the width of roadside, fence construction, habitat type, and distance from street lights measured at 50 m intervals. Data were analyzed to explore which landscape features and temporal factors influenced the occurrence of a roadkill hotspot. Results More kangaroo road mortalities occurred during periods of low temperature and low rainfall, and these factors are likely to affect forage quality. Fewer mortalities occurred when rain was falling. A greater number of mortalities occurred during the waning gibbous phase of the lunar cycle. Significantly more road mortalities occurred a short distance from the end of a section of street lights. Conclusions The findings suggest that illumination influences the likelihood of kangaroo road mortalities. Large herbivores are particularly sensitive to habitat fragmentation because they need unrestricted access to large continuous habitat. Knowledge of factors that influence where and when kangaroos are most likely to cross roads can be used to inform more targeted management strategies and improve future road design and habitat connectivity to reduce the incidence of wildlife vehicle collisions.
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McHugh, Darren, Ross L. Goldingay, and Mike Letnic. "Occupancy and co-occurrence patterns of endemic mammals and introduced predators across a broad geographical gradient in eastern Australia." Biodiversity and Conservation, March 10, 2022. http://dx.doi.org/10.1007/s10531-022-02374-0.
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AbstractInvasive predators, land clearing and altered fire regimes have been implicated in species decline and extinction worldwide. Enhanced knowledge of how these factors interact and influence medium-sized mammals is warranted. We tested three hypotheses using occupancy data for a diverse mammal assemblage including three threatened species, five common species, two introduced mesopredators and an apex predator in eastern Australia. We hypothesised that occupancy of mammal species within the assemblage would be influenced by (i) the physical environment (rainfall, vegetation type and elevation), (ii) habitat disturbance (number of fires and habitat fragmentation) and (iii) mesopredator release, whereby occupancy and/or detection of medium-sized mammals are influenced by mesopredators, the feral cat (Felis catus) and the red fox (Vulpes vulpes), which are influenced by an apex predator, the dingo (Canis familiaris). We utilised camera-trapping data from 173 sites (692 camera locations) across a north–south gradient spanning ~ 1500 km in eastern Australia. Although hypotheses i (physical environment) and ii (habitat disturbance) are not mutually exclusive, we show that the variables considered in each were only weakly correlated. We conducted occupancy modelling to investigate the physical environment and habitat disturbance hypotheses. We conducted co-occurrence modelling to investigate interactions between species. The physical environment hypothesis best supported occupancy models for six mammal species: red-necked pademelon (Thylogale thetis), bandicoots (Isoodon macrourus and Perameles nasuta), swamp wallaby (Wallabia bicolor), red-necked wallaby (Macropus rufogriseus), eastern grey kangaroo (Macropus giganteus) and feral cat. The disturbance hypothesis best supported occupancy models for four mammal species: long-nosed potoroo (Potorous tridactylus), red-necked pademelon and both mesopredators. Support for the mesopredator release hypothesis was equivocal. Large macropods showed site avoidance towards the red fox. Four species showed higher detection at sites where mesopredators were not detected. The fox showed a negative detection interaction to the dingo and the cat did not. Our study highlights how factors such as rainfall, land clearing, elevation and number of fires influence the occupancy of species within a diverse mammal assemblage at the macroecological scale. Our findings have implications for the conservation of threatened species in managed landscapes and suggestions for further research following the recent 2019–2020 wildfires.
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Reeves, Julie, Scott Burnett, and Elizabeth Brunton. "Virtual fencing as a wildlife-vehicle collision mitigation measure: technical function, wildlife response and considerations for installation in an urban environment." Australian Zoologist preprint, no. 2021 (July 19, 2021). http://dx.doi.org/10.7882/az.2021.021.
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ABSTRACT Virtual wildlife fencing presents as a cost-effective measure for roadkill mitigation, which aids in reducing fragmentation of wildlife populations by facilitating safer movement of wildlife across the landscape. In this study, we conducted an audit of a virtual fence installation in south-east Queensland, Australia. We assessed its reliability in flows of traffic and the effect that installation parameters and site conditions had on its effective operation in an urban setting. We made observations on the behavioural response of Eastern Grey Kangaroos Macropus giganteus to the acoustic signals produced by the fence. We found that the fencing activated consistently in response to headlights at dusk and dawn, and when traffic flows were dense, despite considerable variations in the range of installation parameters. However, we identified that the response of the virtual fence to headlights was affected by road curvature and we identified inconsistencies in the timing and pattern of activation in response to traffic. Behavioural observations showed a significant increase in kangaroo vigilance in response to the acoustic signal of the fence when resting or grazing, and kangaroos detected the acoustic signal up to 50 m away. While virtual fencing operates effectively and is a low-cost roadkill mitigation option that can be applied to the urban environment, more research is needed to better understand the effect of its acoustic and visual signals on wildlife behaviour and efficacy in busy urban environments.