- Control and monitoring of kangaroo populations in the Mallee Parks of semi-arid Northwest Victoria
- Remote sensing of trophic cascades: multi-temporal landsat imagery reveals vegetation change driven by the removal of an apex predator
- Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian Grasslands and Grassy Woodlands
- Victoria’s rangelands: In Recovery or in Transition?
- Threatened plant translocation in Australia: A review
- Using evidence of decline and extinction risk to identify priority regions, habitats and threats for plant conservation in Australia
- Density and dispersion of two species of kangaroo in relation to habitat
- Density Distributions and Habitat Associations of Red Kangaroos, Macropus rufus, and Western Grey Kangaroos, M. fuliginosus, in the South Australian Pastoral Zone
- Home ranges of sympatric red kangaroos Macropos rufus, and Western Grey Kangaroos M. fuliginosus, in Western New South Wales
- Is camera trap videography suitable for assessing activity patterns in eastern grey kangaroos?
- Sixteen years of Eastern Barred Bandicoot Perameles gunnii reintroductions in Victoria: a review
- The Effects of Grazing by Kangaroos and Rabbits on the Vegetation and the Habitat of Other Fauna in the Tidbinbilla Nature Reserve, Australian-Capital-Territory
- The impact of grazing by Eastern Grey Kangaroos (Macropus giganteus) on vegetation recovery after fire at Reef Hills Regional Park, Victoria
- Bringing forward the benefits of coarse woody debris in ecosystem recovery under different levels of grazing and vegetation density.
- Birds of a feather flock together: Using trait-groups to understand the effect of macropod grazing on birds in grassy habitats
- Habitat preference of the striped legless lizard: Implications of grazing by native herbivores and livestock for conservation of grassland biota
- Mitigating impacts of weeds and kangaroo grazing following prescribed fire in a Banksia woodland
- Experimental reduction of native vertebrate grazing and addition of logs benefit beetle diversity at multiple scales.
- The concept of overgrazing and its role in management of large herbivores
- Eating away at protected areas: total grazing pressure is undermining public land conservation
- Resource use by the Eastern Grey Kangaroo and the Black Wallaby in a managed remnant woodland community
- Sensitivity of soil organic carbon to grazing management in the semi-arid rangelands of south-eastern Australia
- Management of grazing intensity in the semi-arid rangelands of southern Australia – Effects on soil and biodiversity
- Overabundant kangaroo populations in Southeastern Australia
- Spatial patterns of kangaroo density across the South Australian pastoral zone over 26 years: aggregation during drought and suggestions of long distance movement
- Native vertebrate herbivores facilitate native plant dominance in old fields while preventing native tree invasion – implications for threatened species
- An adaptive management case study for managing macropods on Maria Island National Park, Tasmania, Australia: adding devils to the detail
- The impact of grazing by Eastern Grey Kangaroos (Macropus Giganteus) on vegetation recovery after fire at Reef Hills regional park, Victoria
- What does it take to do successful adaptive management? A case study highlighting Coastal Grassy Woodland restoration at Yanakie Isthmus
- Vegetation responses to stratified kangaroo grazing pressure at Hattah-Kulkyne National Park, 1992-96
- Town roo, country roo: a comparison of behaviour in eastern grey kangaroos (Macropus giganteus) in developed and natural landscapes
- 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)
- Vegetation change, erosion risk and land management on the Nullarbor Plain, Australia
- Are the faecal pellets of kangaroos (Macropus spp.) a source of nutrients and carbon in an inland floodplain wetland during flooding? A preliminary experimental inundation study in the Macquarie Marshes, New South Wales
- Disentangling chronic regeneration failure in endangered woodland ecosystems
- Can threatened species survive where the top predator is absent?
- Novel trophic cascades: apex predators enable coexistence
- Fire and grazing influence food resources of an endangered rock-wallaby
- Foraging behaviour and dispersion of eastern grey kangaroos (Macropus giganteus) in an ideal free framework
- Large herbivore distribution and abundance: intra and interspecific niche variation in the tropics
- Macroecological patterns in mammal abundances provide evidence that an apex predator shapes forest ecosystems by suppressing herbivore and mesopredator abundance
- Mammals of particular conservation concern in the Western Division of New South Wales
- National Recovery Plan for the Brush-tailed Rock-wallaby Petrogale penicillate
- Is the removal of domestic stock sufficient to restore semi-arid conservation areas?
- Predation risk and competitive interactions affect foraging of an endangered refuge-dependent herbivore
- Resolving the value of the dingo in ecological restoration
- Resource pulses and mammalian dynamics: conceptual models for hummock grasslands and other Australia desert habitats
- Eating away at protected areas Total grazing pressure is undermining public land conservation
- Stemming the tide: progress towards resolving the causes of decline and implementing management responses for the disappearing mammal fauna of northern Australia
- Trophic cascades and dingoes in Australia: Does the Yellowstone wolf-elk-willow model apply?
- Top predators as biodiversity regulators: the dingo Canis lupus dingo as a case study
- Predation by red foxes limits recruitment in populations of eastern grey kangaroos
- Linking modelling, monitoring and management: an integrated approach to controlling overabundant wildlife
- Predicting Ecosystem Wide Impacts of Wallaby Management using a Fuzzy Cognitive Map
- Unintended Consequences of Invasive Predator Control in an Australian forest: Overabundant wallabies and vegetation change
- Effects of large native herbivores on other animals
- Interactive effects of fire and large herbivores on web-building spiders
- Herbivory and fire interact to affect forest understory habitat, but not its use by small vertebrates
- The interactive effects of fire and herbivory on understorey vegetation and its dependent fauna
- Gradient analysis of macropod distribution in open forest and woodland in eastern Australia
- A Study of Habitat Preferences in the Grey Kangaroo
- Seasonal movement patterns of the Eastern Grey Kangaroo in Southern Queensland
- Trends in Kangaroo Numbers in Western New South Wales and their relation to Rainfall
- Habitat Utilization by Sympatric Red Kangaroos Macropus-Rufus, and Western Grey Kangaroos Macropus-Fuliginosus, in Western New-South-Wales
- Predation of Red Kangaroos, Macropus rufus, by the Dingo, Canis familiaris dingo (Blumenbach) in North-Western New South Wales
- The Diurnal and Seasonal Patterns of Grazing of the Red Kangaroo, Macropus-Rufus, and the Western Gray-Kangaroo, Macropus-Fuliginosus
- Observations of the behaviour of male eastern grey kangaroos when attacked by dingoes
- Scavengers and detritivores of kangaroo harvest offcuts in arid Australia
- Do fecal odors from native and non-native predators cause a habitat shift among macropods?
- Shifts in macropod home ranges in response to wildlife management interventions
- Density dependence in foraging habitat preference of eastern grey kangaroos
- Mechanisms of drought-induced population decline in an endangered wallaby
- Australia’s Savannah Herbivores: Bioclimatic Distributions and an Assessment of the Potential Impact of Regional Climate Change
- Evaluating the role of the dingo as a trophic regulator in Australian ecosystems
- High macropod populations at Look At Me Now Headland, North Coast NSW: implications for endangered Themeda triandragrasslands on coastal headlands
- The virtuous circle: predator-friendly farming and ecological restoration in Australia
(Morris, Duncan, & Vesk, 2018)
This report explores the kangaroo population programs in the Mallee National Parks of Victoria. Kangaroo populations in the Parks are managed for two interdependent reasons: to prevent large die-offs of kangaroos during drought and to prevent kangaroo grazing from impeding the ecological restoration of degraded semi-arid woodland ecosystems.
Remote sensing of trophic cascades: multi-temporal landsat imagery reveals vegetation change driven by the removal of an apex predator
(Fisher et al, 2021)
Trophic cascade theory predicts that predators indirectly benefit plants by limiting herbivore consumption. As humans have removed large predators from most terrestrial ecosystems the effect of their absence is unrecognized. A manipulation of dingo populations across Australia’s dingo-proof fence, within the Strzelecki Desert, was used to assess how predator absence has altered vegetation cover dynamics at landscape and site scales.
Landscape-scale analysis used Landsat fractional vegetation cover time series statistics to classify landforms and examine vegetation dynamics either side of the dingo fence. Generalised additive models were used to analyse the influence of predator absence on site-scale observations of fauna abundance and vegetation cover. The location of the dingo fence was visible as a change in both the standard deviation and maximum of non-photosynthetic vegetation (NPV) cover (e.g. wood and dry leaves) over 32 years (1988–2020). On average, NPV cover of swales decreased in the standard deviation by 1.4% and in the maximum by 5.0% where dingo abundance was reduced. The differences were consistent with suppressed vegetation growth following rainfall, due to high grazing pressure, where predators were rare. The landscape-scale analysis was supported by site-scale observations. The influence of the trophic cascade was observable at both the landscape and site scales, suggesting that apex predator removal has significantly affected the arid ecosystem’s responses to resource pulses. Analogous effects may exist across the large areas of the planet over which apex predators have been extirpated.
Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian Grasslands and Grassy Woodlands
(Howland, et al., 2014)
Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities.
The management of approach of the reserved rangeland areas in NW Victoria are more akin to “restoration ecology” than the move conventional concept of conservation management of parks and reserves. This report provides an extensive exploration of historical land use as well as the creation of the mallee parks. Management plans include extensive rabbit and kangaroo population management strategies to prevent adverse impacts on regeneration and habitat restoration.
(Silcock, et al., 2019)
This project combined a literature review with extensive consultations with translocation practitioners to compile data on translocations of threatened Australian plants. The evaluation highlights the need to consider translocation in the broad context of conservation actions for species recovery and the need for long-term commitment to monitoring, site maintenance and documentation. Macropod grazing and trampling was a significant factor in the survival rates of some species.
Using evidence of decline and extinction risk to identify priority regions, habitats and threats for plant conservation in Australia
(Silcock & Fensham, 2018)
This project undertook to compile published information and best available field knowledge including 125 expert interviews to identify declining and at risk species of vascular plants. Grazing from kangaroos featured as a threat to many of these at risk species.
A seminal work which investigates the differences in dispersion of red and grey kangaroos which indicated that grey kangaroos are more dependent on cover than red kangaroos and suggests that grey kangaroos frequent areas where they feel safe from observation.
Density Distributions and Habitat Associations of Red Kangaroos, Macropus rufus, and Western Grey Kangaroos, M. fuliginosus, in the South Australian Pastoral Zone
(Cairns, Pople, & Grigg, 1991)
Density distributions of red and western grey kangaroos in the South Australian pastoral zone were determined for the period 1978-1986. The habitat associations of these kangaroos were analysed. Habitat heterogeneity and climatic factors including low evaporation and relatively high rainfall appeared to be the major determinants of the density distribution of western grey kangaroos.
Home ranges of sympatric red kangaroos Macropos rufus, and Western Grey Kangaroos M. fuliginosus, in Western New South Wales
(Priddel, Shepherd, & Wellard, 1988)
Kangaroos are the most significant herbivores on Kinchega National Park. This research involved using radiotracking 48 individual kangaroos over 20 months to determine home ranges. Based on diurnal locations (resting sites) only, home ranges of red kangaroos were larger than those of western greys, but home ranges of kangaroos on Kinchega were smaller than those on the adjacent pastoral leasehold.
(Green-Barber & Old, 2017)
This project assessed the suitability of using cameras to document the behaviour of eastern grey kangaroos by comparing activity patterns collected using cameras to published activity patterns for the species. The findings of this study suggest that camera traps are suitable for assessing the diurnal activity of eastern grey kangaroos and are useful tools for documenting their behaviour.
(Winnard & Coulson, 2008)Examined characteristics affecting the success of Eastern Barred Bandicoot reintroductions, including competition from herbivores. A combination of drought and grazing pressure from kangaroos and rabbits reduced the amount of available habitat and possibly led to population decline of Eastern Barred Bandicoots at one reintroduction site in Victoria.
The Effects of Grazing by Kangaroos and Rabbits on the Vegetation and the Habitat of Other Fauna in the Tidbinbilla Nature Reserve, Australian-Capital-Territory
(Neave & Tanton, 1989)
Examined the status of grassland vegetation in three areas in which exclosures provided protection since 1979 and compared with 1982-1983. Showed that some plants had declined while others increased under high kangaroo grazing and explored habitat implications for other wildlife.
The impact of grazing by Eastern Grey Kangaroos (Macropus giganteus) on vegetation recovery after fire at Reef Hills Regional Park, Victoria
(Meers & Adams, 2008)
This project was aimed at determining the grazing patterns of Eastern Grey Kangaroos after fire and determine the impacts that grazing might have on post fire woody shrub recovery. Found preferential grazing occurred on small burnt plots compared to adjacent unburnt areas and significant reduction in shrub diversity on grazed plots compared to ungrazed plots.
Bringing forward the benefits of coarse woody debris in ecosystem recovery under different levels of grazing and vegetation density.
(Manning, Cunningham, & Lindenmayer, 2012)
Examined the effect of experimentally adding Course Woody Debris, in four different treatments, on reptile abundance in temperate woodlands in south-eastern Australia – one of the most highly degraded vegetation types on the continent. They investigated the influence that varying grazing pressure and vegetation density had on those effects.Found a reduction of grazing was the most effective way of increasing small skink abundance in high density vegetation.
Birds of a feather flock together: Using trait-groups to understand the effect of macropod grazing on birds in grassy habitats
(Howland B. W., et al., 2016)
Investigated the relationship between (1) density of native eastern grey kangaroos and grass structure and (2) grass structure and reptiles. Found reptile abundance, species richness and diversity were highest where grazing intensity was low.
Habitat preference of the striped legless lizard: Implications of grazing by native herbivores and livestock for conservation of grassland biota
(Howland B. W., et al., 2016)
Investigated habitat preferences of Delma Impar at multiple spatial scales and found it was not affected by the size of grassland remnants, but was negatively related to the density of native grazers.
(Brown, Paczkowska, & Gibson, 2016)
Investigated (i) how native and weed species richness and cover changed following autumn prescribed fire and (ii) effectiveness of management techniques at reducing the impacts of grazing by western grey kangaroos. Found fencing significantly increased cover of native shrubs and grasses through prevention of kangaroo grazing. However, kangaroos also appeared to play a role in suppressing weedy annual grasses post-fire in the woodlands.
Experimental reduction of native vertebrate grazing and addition of logs benefit beetle diversity at multiple scales.
(Barton, Manning, Gibb, Lindenmayer, & Cunningham, 2011)
Investigated whether the differences in vertebrate grazing affect the trophic structure of beetle assemblages and a number of other habitat factors. Found a reduction in grazing level had benefits for the abundance and species richness of beetles at the site scale.
Detailed discussion of what overgrazing means under different land uses and impacts of overgrazing in conservation and production landscapes. There are several different ways of defining overgrazing. Native and exotic herbivores can result in overgrazing which can lead to new stable ecosystems states and these new states may be irreversible.
(Prowse, O’Connor, Collard, & Rogers, 2019)
Grazing by domestic and wild mammalian herbivores can have a significant impact on the condition of remnant native vegetation, even if it is formally protected. This project evaluated the evidence for grazing pressure trends in native vegetation covering 180 000km2 of South Australia and employed Bayesian linear mixed-effects modelling and over the 12 year period found grazing severity in protected areas increased to levels closely matching those on private, unprotected land. These researchers suggest that macropod densities have increased substantially over that time frame and this has contributed significantly to the grazing pressure issue.
Resource use by the Eastern Grey Kangaroo and the Black Wallaby in a managed remnant woodland community
(de Munk, 1999)
This work studies the interactions and relationships that exist between Eastern Grey Kangaroos and Black Wallabies in their utilisation of spatial and trophic resources in a managed remnant woodland community. The thesis provides a close understanding of the way in which these species impact upon their habitats. Both species contributed to ecological management problems including lack of shrub and tree recruitment.
Sensitivity of soil organic carbon to grazing management in the semi-arid rangelands of south-eastern Australia
(Orgill, et al., 2017)
This study compared the effects of grazing management on soil organic carbon stocks in the semi-arid rangelands of NSW. Field surveys were conducted at three locations with paired sites of rotational grazing and continuous grazing. In some parts of the landscape higher soil C was found with TGP control. Grazing pressure was determined by domestic livestock records and data from annual aerial surveys of goats and kangaroos.
Management of grazing intensity in the semi-arid rangelands of southern Australia – Effects on soil and biodiversity
(Waters, Orgill, Melville, & Douglas, 2016)
Overgrazing contributes to rangeland degradation altering plant community composition, erosion and biodiversity. This research provides evidence that the effects of grazing management on SOC are mediated by ground cover and increased organic matter supply and/or reduced soil carbon redistribution (erosion), which indicates that the management of grazing intensity may provide a tool to avoid soil carbon loss in rangelands.
Overabundant kangaroo populations in Southeastern Australia
(Coulson G. , 2001)
Review of 5 reserve sites where kangaroos have become overabundant and the control methods adopted. The negative impacts of high kangaroo density include threats to humans, depression of threatened species, decline in body condition of kangaroos, and altered grazing equilibria. Population density has been reduced by culling at all sites, supplemented by fertility control at 3 sites.
Spatial patterns of kangaroo density across the South Australian pastoral zone over 26 years: aggregation during drought and suggestions of long distance movement
(Pople, et al., 2007)
This research went beyond the usual focus of wildlife surveys that estimate population size by using spatial analysis techniques to explore the spatial patterns of density of red and western grey kangaroos over a 26 year period in an area exceeding 200 000km2 in South Australia. The research found considerable year-to-year variation in the spatial patterns of kangaroo density which were too high to be explained by vital rates alone, implying immigration from surrounding areas. “These large shifts in distribution were occasionally to areas that had received better rainfall than the surrounding areas.” The research shows that the Kriged density surface approach allowed improved estimations of kangaroo density, especially on individual properties and also validated that the current divisions for harvest management were appropriate.
Native vertebrate herbivores facilitate native plant dominance in old fields while preventing native tree invasion – implications for threatened species
(Ingram & Kirkpatrick, 2013)
In a world in which reconstruction of the ‘natural’ does not necessarily result in the best outcomes for biodiversity, it is important to consider the implications of management change on faunal populations in protected areas, and on the future of the species that are most in need of protecting. On the old fields of Maria Island National Park, Tasmania we use vegetation data from exclosure plots and adjacent controls to reveal that current populations of native vertebrate herbivores prevent tree and shrub invasion of marsupial lawns and reduce the abundance of introduced plants. This maintenance of marsupial lawns may be less effective after an insurance population of the endangered marsupial carnivore, the Tasmanian Devil Sarcophilus harrisii, is introduced to the island. Native vertebrate herbivores represent potential prey for the devils, impacting on grazing regimes and plant succession. Vegetation change is most likely to favour two threatened bird species, while reducing the prospects for the threatened Tasmanian Devil and potentially threatened Tasmanian Pademelon Thylogale billardierii.
An adaptive management case study for managing macropods on Maria Island National Park, Tasmania, Australia: adding devils to the detail
Adaptive management is driven by structured decision making and evidence from monitoring in a ‘learning’ framework that guides management actions. In a conservation context, this iterative approach includes evaluation of the impacts on natural processes. On Maria Island National Park, Tasmania, Australia, introduced Forester kangaroo, Bennetts wallaby and Tasmanian pademelon have been intensively managed by an annual cull since 1994. Management actions were triggered by high parasite loads, intense grazing pressure and high juvenile mortality during drought periods. Criticism of the annual cull from animal welfare groups initiated the development of an adaptive management approach for decision making that replaces the historic ‘trial and error’ process. Following a comprehensive review of the existing macropod management program in 2011, an integrated monitoring strategy was established to provide evidence for informed decision making. Assessments of animal health and estimates of population trends are the key indicators for management actions to occur. Maintaining viable macropod populations and protecting natural values form the basis of management objectives. Management actions in each year, for each species, represent ‘treatments’ as spatial replication is not possible at such a small scale. An adaptive management approach for macropod management on Maria Island has resulted in only one species being culled in 2014 and 2015 for the first time in almost 20 years. However the recent introduction of a major predator, the Tasmanian devil, has increased uncertainty for long-term macropod management on Maria Island with no cull occurring in 2016 and 2017.
The impact of grazing by Eastern Grey Kangaroos (Macropus Giganteus) on vegetation recovery after fire at Reef Hills regional park, Victoria
(Adams & Meers, 2003-2008)
In southeastern Australia ecological burning is frequently used to maintain a number of plant and animal populations. However, many of these prescribed fires are small, and may focus intense grazing activity on new regrowth. At Reef Hills Regional Park, Victoria shrub species have senesced, presumably due to the absence of fire. Ecological burning may be necessary to promote regeneration, however, the population density of the Eastern Grey Kangaroo (Macropus giganteus) is high (approx 38 per km2), and grazing pressure presents a significant risk to postfire vegetation recovery. An assessment of grazing patterns and their effects on postfire recovery was carried out at Reef Hills Regional Park through grazing exclusion plots. Preferential grazing by Eastern Grey Kangaroos occurred on small burnt plots compared to adjacent unburnt areas as determined by faecal pellet counts. On burnt areas, there was a significant reduction in shrub diversity on grazed plots compared to ungrazed plots. Most observations of kangaroos were of animals grazing on farmland surrounding the Park, and it is likely that any burning might shift grazing from farmland to burnt areas when new growth occurs. This needs to be considered before any ecological burn plan is applied to manage vegetation communities, particularly if the plan requires small areas to be burnt. We recommended that a large area up to 200 ha area be burnt and monitored to determine whether burning larger areas disperses grazing pressure from macropods to a level where impacts on vegetation are reduced and localized plant extinctions do not occur.
What does it take to do successful adaptive management? A case study highlighting Coastal Grassy Woodland restoration at Yanakie Isthmus
(Morgan, et al., 2018)
This case study illustrates the steps necessary to deliver a complex, long-term adaptive management project involving a range of stakeholders at a landscape scale. Perspectives of the land manager, scientist and volunteer help to convey successes and lessons learned.
Vegetation responses to stratified kangaroo grazing pressure at Hattah-Kulkyne National Park, 1992-96
(Sluiter, Allen, Morgan, & Walker, 1997)
Many landscapes worldwide are degraded. Restoration ecology offers a variety of tools to enable managers to restore valued processes to landscapes. One such tool is state-and-transition (S-T) modelling, which provides a way to summarise knowledge of vegetation dynamics, tools for restoration and the impact of restoration activities. A theoretical S-T framework was developed and used to organise the history of degradation and restoration in the semi-arid woodlands of Hattah Kulkyne National Park, north-west Victoria. This process highlighted four main opportunities to enhance restoration success including: exploring where, when and why natural recruitment of key species was occurring, utilising the artificial stimulation of root suckers as an alternative tool to enhance the regeneration of desirable species, understanding and developing techniques to enable regenerating or partially restored woodlands to move to the desirable state of a self-perpetuating, restored woodland and a need to monitor and manage the threat posed by emerging weeds.
Town roo, country roo: a comparison of behaviour in eastern grey kangaroos (Macropus giganteus) in developed and natural landscapes
(Green-Barber & Old, 2018)
Many species have adapted their behaviour to survive in anthropogenically developed environments (hereafter referred to as developed). Eastern grey kangaroos Macropus giganteus are common in developed areas, however very few studies have evaluated their behavioural adaptations to developed landscapes. This study compared the behaviour of eastern grey kangaroos in a developed environment to those surrounded by a natural environment. i Knowledge of the behavioural differences of kangaroos in developed areas will assist in designing management strategies.
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)
(Dawson, McTavish, Munn, & Holloway, 2005)
The Eastern Grey Kangaroo (Macropus giganteus) occurs mostly in the wetter regions of eastern Australia. However, in the past 30-40 years it has moved into more arid regions (rainfall < 250 mm), thus increasing its overlap zone with the xeric adapted Red Kangaroo (Macropus rufus). An increased access to water (supplied for domestic stock) may explain this range extension, but changes in the availability of preferred feed could also be involved. The water use, drinking patterns and thermoregulatory behaviour of these two species of kangaroo have been examined in a semi-free range study, during summer at an arid rangeland site. Foraging was largely nocturnal in both species and during the day they behaved to reduce heat loads.
(Gillieson, Wallbrink, & Cochrane, 1996)
Arid karst landscapes that have been degraded by human activities provide a challenge for rehabilitation and an opportunity to test ideas about the stability and resilience of limestone ecosystems. The Nullarbor Plain is the largest arid karst area in Australia (220 000 km2) and is divided into extensive closed karstic depressions separated by low rocky ridges, while the dominant vegetation is chenopod shrubland. Since European settlement there has been considerable change in the vegetation, with significant reduction in shrub and grass cover over large areas of the plain. These changes are related to a state and transition model of vegetation dynamics which incorporates climatic variability, fire history and grazing pressure from sheep, kangaroos and rabbits.
Are the faecal pellets of kangaroos (Macropus spp.) a source of nutrients and carbon in an inland floodplain wetland during flooding? A preliminary experimental inundation study in the Macquarie Marshes, New South Wales
(Kobayashi, Iles, & Knowles, 2011)
Kangaroos (Macropus spp.) are one of the most abundant native macrofauna on Australian floodplains with a positive relationship between their density and the deposition of faecal pellets that contain nutrients and carbon. This project tested whether kangaroo faecal pellets are a source of nutrients and carbon during flooding in the Macquarie Marshes, an inland floodplain wetland, in south-eastern Australia. Nutrient and carbon depositions to floodplains in the form of faecal pellets from large terrestrial animals such as kangaroos are an important process of cycling these elements in inland floodplain wetlands, especially where large populations of these animals occur.
(Bennett, Duncan, Rumpff, & Vesk, 2020)
Ecological restoration of degraded ecosystems requires the facilitation of natural regeneration by plants, often augmented by large-scale active revegetation. The success of such projects is highly variable. Risk factors may be readily identifiable in a general sense, but it is rarely clear how they play out individually, or in combination. We addressed this problem with a field experiment on the survival of, and browsing damage to, 1275 hand-planted buloke (Allocasuarina luehmannii) seedlings in a nationally endangered, semi-arid woodland community.
(Wallach, Murray, & O’Neill, 2008)
Top predators have been described as highly interactive keystone species. Their decline has been linked to secondary extinctions and their increase has been linked to ecological restoration. Several authors have recently argued that the dingo Canis lupus dingo is another example of a top predator that maintains mesopredators and generalist herbivores at low and stable numbers, thereby increasing biodiversity and productivity. Due to the sensitivity of many Australian species to introduced mesopredators and herbivores, the top predator hypothesis predicts that threatened species will not survive where dingoes are rare or absent. However, several threatened species have survived inside the Dingo Barrier Fence (DBF). We present a new view on the survival of the yellow-footed rock-wallaby Petrogale xanthopus xanthopus and the malleefowl Leipoa ocellata inside the DBF where the dingo is considered very rare, or in areas where the dingo is believed to have been eradicated several decades ago.
(Wallach, Ripple, & Carroll, 2015)
Novel assemblages of native and introduced species characterize a growing proportion of ecosystems worldwide. Some introduced species have contributed to extinctions, even extinction waves, spurring widespread efforts to eradicate or control them. We propose that trophic cascade theory offers insights into why introduced species sometimes become harmful, but in other cases stably coexist with natives and offer net benefits. Large predators commonly limit populations of potentially irruptive prey and mesopredators, both native and introduced. This top-down force influences a wide range of ecosystem processes that often enhance biodiversity. We argue that many species, regardless of their origin or priors, are allies for the retention and restoration of biodiversity in top-down regulated ecosystems.
(Tuft, Crowther, & McArthur, 2012)
Fire and grazing have complex and interacting impacts on food resources available to endangered herbivores and can potentially be manipulated as part of conservation strategies. Aims. We examined the interacting impacts of fire and grazing on the food resources available to a colony of endangered brush-tailed rock-wallabies (Petrogale penicillata) to test fire as a potential management tool. Methods. We conducted two manipulative experiments using a repeated-measures split-block design. We measured the effects of grazing and strategic burning on total vegetation biomass and on particular plants selected by rock-wallabies.
Foraging behaviour and dispersion of eastern grey kangaroos (Macropus giganteus) in an ideal free framework
(Maguire, Ramp, & Coulson, 20016)
Ideal free distribution (IFD) theory predicts that animals in competitive situations should distribute themselves among available habitat patches according to the density of conspecifics and its regulatory effect on resources. To investigate the applicability of IFD models to free-ranging herbivores, we quantified the disper-sion and foraging behaviour of eastern grey kangaroos Macropus giganteus among habitat patches of differing suitability, within and outside a reservoir catchment in southern Victoria, Australia. Kangaroo densities within the catchment had a regulatory effect on resource density, while surrounding farmland maintained a higher standing crop despite higher densities of competitors.
(Ritchie, et al., 2008)
Determining the biological and environmental factors that limit the distribution and abundance of organisms is central to our understanding of the niche concept and crucial for predicting how species may respond to large-scale environmental change, such as global warming. However, detailed ecological information for the majority of species has been collected only at a local scale, and insufficient consideration has been given to geographical variation in intraspecific niche requirements. To evaluate the influence of environmental and biological factors on patterns of species distribution and abundance, we conducted a detailed, broadscale study across the tropical savannas of northern Australia on the ecology of three large, sympatric marsupial herbivores (family Macropodidae): the antilopine wallaroo (Macropus antilopinus), common wallaroo (M. robustus), and eastern grey kangaroo (M. giganteus).
Macroecological patterns in mammal abundances provide evidence that an apex predator shapes forest ecosystems by suppressing herbivore and mesopredator abundance
(Colman, Crowther, & Letnic, 2015)
Apex predators often exert strong, top‐down effects on ecosystems, and their removal can result in the dramatic reorganization of ecosystems owing to herbivores and smaller predators becoming the dominant trophic‐regulating species. However, field studies designed to understand the influence that apex predators have on ecosystems are hampered by the large spatial and temporal scales required. Here, we use pre‐existing datasets to test predictions on the direct and indirect effects of apex predators on mammals and vegetation generated from trophic cascade theory and the mesopredator release hypothesis.
(Dickman, Pressey, Lim, & Parnaby, 1996)
The Western Division of New South Wales is an administrative region of 325 000 km2 on the eastern fringe of the Australian arid zone. Since European settlement in 1788, 71 species of native mammals have been recorded in the Division, seven more have been documented only as subfossils, and a further 15 species occur within 100 km of the Divisional boundary. At least 27 of the original species have become regionally extinct, and a further 11 have declined in distribution. As in other regions of Australia, species losses have been greatest for rodents and marsupials in a critical weight range of 35–5500 g, and least for bats. However, percentage losses among the terrestrial fauna are high relative to other regions, and probably reflect both the early settlement of New South Wales and the marginal distribution in the Division of 49% of the original fauna. Feral cats are implicated in the regional extinction of up to ten species of native mammals prior to 1857.
(Menkhorst & Hynes, 2011)
The Brush-tailed Rock-wallaby (Petrogale penicillata) is a medium-sized marsupial macropod that was formerly widely distributed in south-eastern Australia, from south-eastern Queensland through eastern and central New South Wales and the Australian Capital Territory to western Victoria. It has suffered a widespread decline in range and abundance, with a major range contraction and local extinctions in many areas, especially in the south and west of its distribution. The species now survives mostly on isolated rocky escarpments along the Great Dividing Range from south-eastern Queensland through eastern New South Wales to eastern Victoria. Historical and current threats include hunting, predation, habitat loss, competition with other species and loss of genetic diversity. The Brush-tailed Rock-wallaby is listed as Vulnerable under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. It is also listed as Vulnerable under the Queensland Nature Conservation Act 1992, Endangered under the New South Wales Threatened Species Conservation Act 1995, Endangered under the Australian Capital Territory Nature Conservation Act 1980, and Threatened under the Victorian Flora and Fauna Guarantee Act 1988. This Recovery Plan for the Brush-tailed Rock-Wallaby is the first national recovery plan for the species, and details its distribution, habitat, threats and recovery objectives and actions necessary to ensure its long-term survival.
(Page & Beeton, 2000)
Increasingly, conservation areas are proclaimed in non-pristine environments that have biodiversity values and the issue of how to change the management regime to restore such landscapes arises. Before gazettal in 1992, Currawinya National Park (28°52’S, 144°30’E) in south-west Queensland’s mulga lands was grazed by domestic stock for over 130 years. Following gazettal, the area was destocked and a monitoring programme initiated to determine the response by the vegetation. This paper describes the grass dynamics in three vegetation communities on Currawinya National Park with three different grazing regimes. Data are presented for an on-park site (native and feral herbivores present), an off-park site (domestic, native and feral herbivores were present), and an exclosure (no mammalian herbivores present). The results show that removal of domestic livestock alone is not sufficient to promote rapid recovery of grass populations and suggest that conservation area managers must reduce native herbivore numbers as well if the desired outcome is a return to the supposed “natural” condition.
Predation risk and competitive interactions affect foraging of an endangered refuge-dependent herbivore
(Tuft K. D., Crowther, Connell, Muller, & McArthur, 2011)
Predators can have non-lethal effects on prey by causing animals to restrict their foraging in order to avoid predation risk. These effects can be of conservation concern when an introduced predator constrains the foraging behaviour of a threatened species, and therefore its access to resources. We examined the spatial response of foraging in endangered brush-tailed rock-wallabies to predation risk and food while taking into account the potentially competitive role of sympatric herbivores.
(Newsome, et al., 2015)
There is global interest in restoring populations of apex predators, both to conserve them and to harness their ecological services. In Australia, reintroduction of dingoes (Canis dingo) has been proposed to help restore degraded rangelands. This proposal is based on theories and the results of studies suggesting that dingoes can suppress populations of prey (especially medium‐ and large‐sized herbivores) and invasive predators such as red foxes (Vulpes vulpes) and feral cats (Felis catus) that prey on threatened native species. However, the idea of dingo reintroduction has met opposition, especially from scientists who query the dingo’s positive effects for some species or in some environments. Here, we ask ‘what is a feasible experimental design for assessing the role of dingoes in ecological restoration?’
Resource pulses and mammalian dynamics: conceptual models for hummock grasslands and other Australia desert habitats
(Letnic & Dickman, 2009)
Resources are produced in pulses in many terrestrial environments, and have important effects on the population dynamics and assemblage structure of animals that consume them. Resource-pulsing is particularly dramatic in Australian desert environments owing to marked spatial and temporal variability in rainfall, and thus primary productivity. Here, we first review how Australia’s desert mammals respond to fluctuations in resource production, and evaluate the merits of three currently accepted models (the ecological refuge, predator refuge and fire-mosaic models) as explanations of the observed dynamics. We then integrate elements of these models into a novel state-and-transition model and apply it to well-studied small mammal assemblages that inhabit the vast hummock grassland, or spinifex, landscapes of the continental inland.
(Prowse T. A., O’Connor, Collard, & Rogers, 2019)
Protected areas are critical for the long-term conservation of biodiversity globally. Across agricultural landscapes, protected areas serve as refuges for threatened and declining species and provide valuable ecosystem services that support broader landscape function. However, increasing pressure on protected areas from a range of sources is undermining their unique conservation values. Much of the native vegetation remaining in southern Australia is now protected from broad-scale clearing, but the management of threats within these areas could be inadequate to maintain their biodiversity. In particular, grazing by domestic and wild mammalian herbivores can have a significant impact on the condition of remnant native vegetation, even if it is formally protected. We evaluated the evidence for grazing-pressure trends in native vegetation in both protected and unprotected areas across an agricultural landscape covering c. 180 000 km2 of South Australia.
Stemming the tide: progress towards resolving the causes of decline and implementing management responses for the disappearing mammal fauna of northern Australia
(Ziembicki, et al., 2015)
Recent studies at sites in northern Australia have reported severe and rapid decline of several native mammal species, notwithstanding an environmental context (small human population size, limited habitat loss, substantial reservation extent) that should provide relative conservation security. All of the more speciose taxonomic groups of mammals in northern Australia have some species for which their conservation status has been assessed as threatened, with 53 % of dasyurid, 47 % of macropod and potoroid, 33 % of bandicoot and bilby, 33 % of possum, 30 % of rodent, and 24 % of bat species being assessed as extinct, threatened or near threatened. However, the geographical extent and timing of declines, and their causes, remain poorly resolved, limiting the application of remedial management actions.
(Morgan, Hunter, Ballard, Reid, & Fleming, 2016)
Wolves are widely regarded as top-down regulators of prey and trophic cascades in North America. Consequent expectations of biodiversity benefits from canid-driven trophic cascades have driven debate around reintroduction plans for dingoes in south-eastern Australia. The biophysical characteristics of Yellowstone National park predispose that environment to trophic cascades but it is not clear that Australia provides a comparative context for dingoes. The wolf–elk–willow trophic cascade in Yellowstone National Park provides a key case study for understanding the broader system controls on trophic interactions. Here, we compare similarities and dissimilarities of the Yellowstone National Park model and the south-eastern Australian environments where dingo reintroductions have been proposed.
(Letnic, Ritchie, & Dickman, 2012)
Top‐order predators often have positive effects on biological diversity owing to their key functional roles in regulating trophic cascades and other ecological processes. Their loss has been identified as a major factor contributing to the decline of biodiversity in both aquatic and terrestrial systems. Consequently, restoring and maintaining the ecological function of top predators is a critical global imperative. Here we review studies of the ecological effects of the dingo Canis lupus dingo, Australia’s largest land predator, using this as a case study to explore the influence of a top predator on biodiversity at a continental scale.
(Banks, Newsome, & Dickman, 2000)
We investigated the impact of red fox (Vulpes vulpes Linnaeus 1758) predation on juvenile eastern grey kangaroos (Macropus giganteus Shaw 1790) using a replicated predator removal experiment. In two sites in Namadgi National Park, south-eastern Australia, a persistent 1080 poisoning campaign over 18 months reduced fox density by more than 85%, and to less than 10% of the fox density in two other sites with no fox baiting. Changes in the mother : young ratios and densities of kangaroo populations were monitored twice monthly along 2-km transects in each site from July 1993 to February 1995. Compared to nonremoval sites, where foxes were controlled, 25–40% more females retained juveniles over the period when these young became emergent from the pouch. This higher survival of emergent pouch young resulted in a significantly higher proportion of juveniles in kangaroo populations at fox control sites, which resulted in a significantly higher annual growth rate. We conclude that predation upon juveniles is an important limiting factor for kangaroo populations in Namadgi NP
Linking modelling, monitoring and management: an integrated approach to controlling overabundant wildlife
(Chee & Wintle, 2010)
Overabundant wildlife can cause economic and ecological damage. Therefore population control typically seeks to maintain species’ abundance within desired control limits. Efficient control requires targets, methods for estimating population size before and after control, and reliable means of forecasting population size. Demographic stochasticity, environmental variability and model uncertainty complicate these tasks. Monitoring provides critical feedback in the control process, yet examples of integrated monitoring and management are scarce. Synthesis and applications. We provide a general and flexible framework for integrated monitoring and culling when the objective is to keep a species’ abundance within control limits. Our framework explicitly deals with uncertainty arising from demographic stochasticity, ecological complexity and lack of knowledge, and provides the foundation for maximizing efficiency and cost‐effectiveness of control operations. Our approach could be applied in any instances where control is effected via culling.
(Dexter, Ramsey, McGregor, & Lindenmayer, 2012)
At Booderee National Park, south-eastern Australia, the intensive control of the introduced red fox (Vulpes vulpes) resulted in a major increase in the abundance of a browsing macropod, the swamp wallaby (Wallabia bicolor). This has led to a major decrease in the abundance and biomass of a range of palatable plant species. Fox control has also started a trophic cascade that has resulted in a decline in the abundance of the greater glider (Petauroides volans) a folivorous arboreal marsupial, mediated either through increased predation by owls or increased competition with common brushtail possums (Trichosurus vulpecula). We identified five potential scenarios for managing the effects of over-abundant swamp wallabies on the ecosystem as a whole. These were (1) the present scenario of continued intensive fox control and four possible scenarios to redress the problem: (2) ceasing fox control; (3) intensive fox control and intensive wallaby control; (4) introducing dingoes and ceasing fox control; and (5) introducing dingoes and maintaining fox control. We used an ecosystem modelling approach based on a fuzzy cognitive map (FCM) to predict relative estimates of abundance for each scenario for a wide range of taxa in the Booderee National Park ecosystem likely to be affected by each scenario. We addressed uncertainty in our knowledge of the interactions between species by creating alternative models of the system by removing one or more of the uncertain links between species and varying the strength of the remaining interactions in the FCM and aggregated predictions from 100,000 models to estimate the effect of uncertainty on the predictions from our FCM model. In comparison with the current scenario of intensive fox control, scenario 3 had the greatest likelihood of improving the status of palatable plants. Scenarios 2 and 4 reduced the abundance of a range of medium-sized mammals but improved the status of greater gliders, whereas the predicted effects of scenario 5 were uncertain. The FCM modelling approach developed here provided a valuable tool for managers to learn about the potential ecosystem wide effects of management actions while incorporating the likely effects of uncertain knowledge on system outcomes.
(Dexter, Hudson, James, MacGregor, & Lindenmayer, 2013)
Over-abundance of native herbivores is a problem in many forests worldwide. The abundance of native macropod wallabies is extremely high at Booderee National Park (BNP) in south-eastern Australia. This has occurred because of the reduction of exotic predators through an intensive baiting program, coupled with the absence of other predators. The high density of wallabies at BNP may be inhibiting the recruitment of many plant species following fire-induced recruitment events. We experimentally examined the post-fire response of a range of plant species to browsing by wallabies in a forest heavily infested with the invasive species, bitou bush Chrysanthemoides monilifera. unbrowsed plots probably because of reduced competition with more palatable angiosperms. Twelve months after plots were installed the community structure of the browsed and unbrowsed plots was significantly different (P = 0.023, Global R = 0.091). The relative abundance of C. monilifera and P. esculentum contributed most to the differences. We discuss the possible development of a low diversity bracken fern parkland in Booderee National Park through a trophic cascade, similar to that caused by overabundant deer in the northern hemisphere. We also discuss its implications for broad scale fox control in southern Australian forests.
(Foster, Barton, & Lindenmayer, 2014)
Large mammalian herbivores are major drivers of the structure and function of terrestrial ecosystems world‐wide, and changes in their abundance have resulted in many populations being actively managed. Many empirical studies have identified that abundant mammalian herbivores can have negative impacts on biodiversity, but there has been no specific review of the impacts of native mammalian herbivores. We assessed the peer‐reviewed literature on the effects of large native herbivores on other animals. We aimed to quantitatively synthesize current knowledge, identify gaps and limitations in the literature, and highlight priorities for future research.
(Foster C. , Barton, Wood, & Lindenmayer, 2015)
Altered disturbance regimes are a major driver of biodiversity loss worldwide. Maintaining or re-creating natural disturbance regimes is therefore the focus of many conservation programmes. A key challenge, however, is to understand how co-occurring disturbances interact to affect biodiversity. We experimentally tested for the interactive effects of prescribed fire and large macropod herbivores on the web-building spider assemblage of a eucalypt forest understorey and investigated the role of vegetation in mediating these effects using path analysis. Fire had strong negative effects on the density of web-building spiders, which were partly mediated by effects on vegetation structure, while negative effects of large herbivores on web density were not related to changes in vegetation. Fire amplified the effects of large herbivores on spiders, both via vegetation-mediated pathways and by increasing herbivore activity.
(Foster C. N., et al., 2015)
Herbivory and fire are two disturbances that often co‐occur, but studies of their interactive effects are rare outside of grassland ecosystems. We experimentally tested the interactive effects of prescribed fire and macropod herbivory on forest understory vegetation and its vertebrate fauna. Fire and herbivory interacted synergistically to affect forest understory vegetation, with palatable plants showing poor post‐fire recovery in unfenced sites compared with herbivore exclusion sites. Despite this strong interactive effect on vegetation, small vertebrates responded to the individual, and not the interactive effects of disturbance.
(Foster C. , 2015)
Interactions between multiple disturbances have been shown to have unexpected, and often undesirable effects on ecosystems and biodiversity. Improving our ability to predict and manage the outcomes of multiple disturbances is therefore an important research priority. In this thesis, I focused on the interaction between fire and grazing (or browsing) by large herbivores. Evidence of the individual effects of fire and large herbivores is substantial, but there has been little quantitative synthesis of the effects of native herbivores on biodiversity. Using a systematic review and meta-analysis, I found that high densities of large herbivores usually have negative effects on other animals. However, I found that interactions between large herbivores and episodic disturbances, such as fire, remain poorly understood. I therefore designed a field experiment to test the interactive effects of prescribed fire and large herbivores on forest flora and fauna.
(Southwell, Cairns, Pople, & Delaney, 1999)
Patterns of macropod abundance along environmental gradients were examined from data collected on transects located in open forest, woodland, and pasture close to forest or woodland, throughout eastern Australia from latitudes 18–33°S. Nine species of macropod were recorded on the transects. Patterns of ecological separation of the species along the gradients are examined and discussed.
In a state forestry reserve in south-eastern Queensland, indices of grey kangaroo abundance were obtained from faecal pellet counts and were related to habitat structure by analysis of variance, multiple regression and cluster analysis. Of these, cluster analysis proved the most effective technique. Results identified a preference for habitats displaying an abundance of food reserves and shelter. Climax forest and open woodland type habitats were relatively little used.
A 2-y study was made of seasonal movement patterns of the eastern grey kangaroo, Macropus giganteus, in the Warwick district of south-eastern, and the Bollon district of south-western, Queensland. Faecal pellet counts were used to obtain indices of kangaroo usage of cleared country adjacent to cover. Kangaroos were sensitive to changes in forage status, particularly pasture phenology. As quality and quantity of forage reserves declined, animals made progressively greater use of cleared areas. This resulted in marked seasonal changes in distribution patterns. Of the variables quantified (rainfall, soil moisture storage and pasture growth), rainfall provided the best correlations with kangaroo usage of cleared country, explaining 55% (P = 0.002) of the variation in distribution at Warwick and 91% (P = 0.001) of that at Bollon.
(Caughley, Bayliss, & Giles, 1984)
Annual aerial counts of kangaroos within randomly selected blocks of the western plains of New South Wales showed that the numbers of kangaroos doubled between 1975-76 and 1982, and that the widespread drought of 1982 reduced the populations on average by 43%. Localized reductions of similar magnitude occurred after regional droughts in 1977 and 1980 within parts of the monitored area. The observed trends in kangaroo numbers, with eastern and western blocks treated separately, were correlated with annual rainfall with a time lag of 6 months in the response. The relationships show that kangaroos reach their maximum rate of increase following rainfall 100 mm above the annual average in the east and approximately 50 mm above the annual average in the west. At average annual rainfall kangaroos increase at 25% (greys) and 35% (reds) per annum in the east and at 25% (greys) and 30% (reds) per annum in the west. Rate of increase is zero when rainfall is 100 mm below average in the east and approximately 60 mm below average in the west. When rainfall is below these values, kangaroo numbers decline.
Habitat utilisation by sympatric red kangaroos, Macropus rufus, and western grey kangaroos, M. fuliginosus, was monitored by aerial survey. Red kangaroos used floodplain and sandplain with equal intensity. Western grey kangaroos favoured floodplain and utilised woodland on both landforms relatively more than did red kangaroos. Movements of kangaroos between sandplain and floodplain paralleled changes in pasture condition. Red kangaroos responded to pasture growth, moving to sandplain immediately after rain. Western greys followed up to 3 months later, the increase in use of sandplain being weakly correlated (r = 0.70) to an increase in pasture biomass. There was no evidence of any temporal change in use of either woodland or open plain by either species.
Over 7 weeks a group of five dingoes killed 83 red kangaroos within 150 m of a watering point in north-western New South Wales. All except three of these kangaroos were juveniles. Detailed autopsies were performed on 17 of the dead kangaroos: primary predation was the only significant gross pathological finding; the dingoes had eaten portions from about half the kangaroos killed. The daily rate of killing was estimated to be about 0.38 kg prey per kg predator. The rate of killing and the selection for juvenile kangaroos suggested that dingoes could have a direct effect on kangaroo densities by limiting rate of increase. The significance of this finding is discussed with reference to the difference in abundance of kangaroos between the New South Wales and Queensland sides of the border fence.
(Priddel D. , 1986)
Free-ranging red and western grey kangaroos were fitted with radio transmitters which, when the kangaroo grazed, emitted a pulse rate different to that emitted during other activities. Red kangaroos grazed for between 7.1 and 10.5 h day-1; western grey kangaroos grazed for between 5.9 and 9.8 h day-1 . Red kangaroos grazed for the same amount of time each season despite fourfold changes in pasture biomass. The grazing time of western grey kangaroos was similar in autumn, winter and spring, but decreased by 22% in summer when pasture was most abundant. Males of both species grazed for about an hour longer than females each day. Most grazing (78% for red kangaroos; 86% for western grey kangaroos) took place between sunset and sunrise. The distribution of grazing activity with respect to time of day was bimodal; kangaroos grazed for extensive periods during the 6 h immediately after sunset and again during the few hours before and after sunrise. The time of grazing changed seasonally and these changes were associated with differences in day length.
Interactions between dingoes and male eastern grey kangaroos observed at Wallaby Creek (in northeastern New South Wales) are described. Other than simple flight, large male kangaroos can react to dingoes by defending themselves or fleeing to water. A male kangaroo defended himself during an encounter lasting over 60min. His actions included high-standing, kicking, thumping the tail, and hopping towards and watching the dingo. The encounter was made up of six intense bouts, during which the dingo was within 5m of the kangaroo. Most bouts involved the dingo circling and the kangaroo turning to face the dingo, with the kangaroo’s degree of reaction depending on the distance to the dingo. The response of the kangaroo diminished during later bouts. A second kangaroo fled to water when pursued by a dingo and after swimming to shallow water lowered his body so only his head showed. The dingo remained on the bank watching for some time. Both encounters ended with the dingo leaving.
(Read & Wilson, 2004)
The role of the offcuts of harvested kangaroos as a food source for native and introduced scavengers and detritivores was examined in the Roxby Downs region of arid South Australia. Corvids were the prominent users of offcuts in January and eagles and foxes significant users in September. Meat ants and a suite of carrion-specialist beetles and maggots also assisted with the decomposition of kangaroo offcuts. Harvested kangaroo populations provided a more reliable and better utilised food resource for scavengers and detritivores than did kangaroos that died naturally of heat stress. Kangaroo harvesting probably supports elevated populations of foxes, corvids, wedge-tailed eagles and detritivores. Therefore, kangaroo harvesters have a responsibility to control foxes, particularly in regions where endangered mammals or lambs are present.
(Cox, Murray, Bengsen, Hall, & Li, 2014)
Predator-odor-based repellents have benefits as humane, non-lethal management tools that may reduce the need for lethal control in some areas. Macropods (such as kangaroos and wallabies) are iconic Australian native marsupials; however, some are considered important rangeland pests, and their presence in the urban and peri-urban environment often results in conflict. The management of these macropods is a contentious and volatile issue.We evaluated lion (Panthera leo), Sumatran tiger (P. tigris sumatrae), and dingo (Canis lupus dingo) fecal odors as short-term odor-based repellents for wild eastern grey kangaroos (Macropus giganteus) and red-necked wallabies (M. rufogriseus). These odors were used to ‘protect’ highly palatable food sources; with any food not consumed (residue) collected and weighed each day.
(Wiggins, Bowman, McMahon, & McCallum, 2010)
The movement patterns of individual animals define their home range and govern their mode of population dispersal. Understanding how the individual movement patterns and dispersion of a population change following wildlife management interventions is crucial for effective population management. We quantified the impacts of two wildlife management strategies; a lethal intervention and a barrier intervention, on localised populations of the two most common macropod species across the Tasmanian landscape: the Tasmanian pademelon (red-bellied pademelon, rufous wallaby [Thylogale billardierii]) and the Bennett’s wallaby (red-necked wallaby [Macropus rufogriseus rufogriseus]. This manipulation allowed us to examine two competing hypotheses concerning the distribution of individuals in animal populations – the Ideal Free Distribution (IFD) hypothesis and the Rose Petal (RP) hypothesis.
(Ramp & Coulson, 1998)
For a free-ranging forager, the suitability of a patch is dependent on population density, resource supply, resource quality, and the costs of foraging or dispersal. We quantified differences among three foraging habitats and compared this variation to temporal patterns of habitat preference by free-ranging eastern grey kangaroos, Macropus giganteus. We investigated selection on a fine-grained spatial scale, and asked whether habitat preference is constrained by density-dependent mechanisms. Variation in the quantity and quality of resources among habitats was greatest during spring, when biomass and quality were highest, and differences among habitats were most pronounced. However, consistent and discernable differences among habitats were not obtained, indicating that the system fluctuated around an equilibrium state. Using isodar regressions to examine the consumer-density relationships among habitats, open-woodland habitat was favoured over the two open-forest habitats for foraging. Seasonal isodars indicated that density dependence regulated preference between the three foraging habitats during autumn, spring and summer, but not during winter, when variability in resources among habitats was lowest.
(Hoyle, Blomberg, & Fisher, 2001)
The bridled nailtail wallaby is restricted to one locality in central Queensland, Australia. The population declined severely during a major drought between 1991 and 1995. We investigated age-specific covariates of survival and proximate causes of mortality from 1994 to 1997, using mark–recapture and radio-tagging techniques at two study sites. Using a matrix population model, we also modelled the effect of drought on age-specific survival and the intrinsic rate of population increase, λ. The only significant covariate of survival for adults was a measure of health unrelated to drought. Rainfall, food, predator activity, year, sex and habitat were not associated with variation in adult survival. Juvenile survival was negatively affected by drought, and predation was the proximate cause of most juvenile deaths. The matrix projection model showed that the observed juvenile survivorship during the drought was low enough to have produced a population decline, although fecundity and survival of other age classes was high throughout the study.
Australia’s Savannah Herbivores: Bioclimatic Distributions and an Assessment of the Potential Impact of Regional Climate Change
(Ritchie & Bolitho, 2008)
The aims of this investigation were to define and compare the climatic conditions that influence the current distributions of four sympatric large macropodids in northern Australia (Macropus antilopinus, Macropus robustus, Macropus giganteus, and Macropus rufus) and to predict the potential future impact of climate change on these species. The results suggest that contemporary distributions of these large macropodids are associated with well-defined climatic gradients (tropical and temperate conditions) and that climatic seasonality is also important. Bioclimatic modeling predicted an average reduction in northern Australian macropodid distributions of 48%_16.4% in response to increases of 2.0_C. At this temperature, the distribution of M. antilopinus was reduced by 89%_0.4%. We predict that increases of 6.0_C may cause severe range reductions for all four macropodids (96%_ 2.1%) in northern Australia, and this range reduction may result in the extinction of M. antilopinus.
(Glen, Dickman, Soule, & Mackey, 2007)
The importance of strongly interactive predators has been demonstrated in many ecosystems, and the maintenance or restoration of species interactions is a major priority in the global conservation of biodiversity. By limiting populations of prey and/or competitors, apex predators can increase the diversity of systems, often exerting influences that cascade through several trophic levels. In Australia, emerging evidence points increasingly towards the dingo (Canis lupus dingo) as a strongly interactive species that has profound effects on ecosystem function.
Through predatory and competitive effects, dingoes can alter the abundance and function of mesopredators including the introduced red fox (Vulpes vulpes) and feral cat (Felis catus), and herbivores including the European rabbit (Oryctolagus cuniculus). These effects often benefit populations of native prey, and diversity and biomass of vegetation, but may not occur under all circumstances. Despite abundant observational evidence that the dingo is a strong interactor, there have been few attempts to test its ecological role experimentally. Given the well-recognized importance of species interactions to ecosystem function, it is imperative that such experiments be carried out.To do this, we propose three broad questions: (i) do dingoes limit the abundance of other predators or prey? (ii) do dingoes affect the ecological relationships of other predators or prey (e.g. by altering their spatial or temporal activity patterns)? and (iii) does the removal or reintroduction of dingoes entrain ecological cascades?
High macropod populations at Look At Me Now Headland, North Coast NSW: implications for endangered Themeda triandragrasslands on coastal headlands
(Hunter & Hunter, 2019)
High grazing pressure from over-abundant macropods (kangaroos) is perceived to have a detrimental impact on biodiversity. Studies have shown potential changes in state and retardation of degraded vegetation recovery while other investigations have shown correlations with increased floristic diversity. The responses of grasslands to high impact macropod grazing may not be universal. Endangered Themeda triandra-dominated grasslands, on coastal headlands of New South Wales (NSW) and the associated threatened flora are thought to be negatively affected by high macropod grazing. We assess these assumptions via a comparative investigation across 46 headlands (467 plots) on the North Coast of NSW, and a BACI (Before and After Control Incident) design grazing exclusion experiment at a particularly significant site. We compare floristic richness, species density, evenness, Shannon H, Whittaker Beta Diversity, occurrence of listed threatened flora, average sward height and macropod density. Look At Me Now Headland (LAMN), between Coffs Harbour and Woolgoolga has one of the highest recorded population densities of macropods. Here permanent plots were placed with grazing exclusion cages erected around half. Sampling occurred annually (October-26 November) for four consecutive years (2015-2018). Under high macropod grazing pressure LAMN Headland was found to have the highest scores for total richness, species density, species diversity and moderate to high values for species evenness and beta diversity. Within grazing exclusion plots the sward height increased significantly and was associated with a significant decrease in species density, beta and alpha diversity. Our results indicate that macropod grazing, even at the highest intensities, may be beneficial to floristic species diversity within the endangered Themeda-grasslands of coastal headlands and seacliffs within the North Coast Bioregion of NSW; our broader comparative study would suggest that this may also be the case on other headlands.
(Johnson & Wallach, 2016)
In Australia, dingoes are widely regarded as enemies of livestock, and accordingly livestock producers commonly attempt to reduce or eradicate them by lethal control. This can have two forms of perverse outcomes: lethal control often does not succeed in reducing dingo populations and can even result in increased attacks on livestock; and the environmental benefits provided by dingoes, some of which are valuable to livestock production, are lost.We describe these outcomes and suggest mechanisms by which tolerance of dingoes could provide benefits to livestock enterprises, at the same time widening the scope of ecological restoration, and humane treatment of wildlife in Australia.