Land use and dingo baiting are correlated with the density of kangaroos in rangeland systems

Rangelands worldwide have been subject to broadscale modification, such as widespread predator control, introduction of permanent livestock water and altered vegetation to improve grazing. In Australia, these landscape changes have resulted in kangaroos (i.e. large macropods) populations increasing over the past 200 years. Kangaroos are a key contributor to total grazing pressure and in conjunction with livestock and feral herbivores have been linked to land degradation. We used 22 years of aerial survey data to investigate whether the density of 3 macropod species in the southern rangelands of Western Australia was associated with: (i) land use, including type of livestock, total livestock, density of feral goats, type of land tenure, and kangaroo commercial harvest effort; (ii) predator management, including permitted dingo control effort, estimated dingo abundance, and presence of the State Barrier Fence (a dingo exclusion fence); and (iii) environmental variables: ruggedness, rainfall, fractional cover, and total standing dry matter. Red kangaroos (Osphranter rufus) were most abundant in flat, open vegetation, on pastoral land, where area permitted for dingo control was high, and numbers were positively associated with antecedent rainfall with a 12-month delay. Western grey kangaroos (Macropus fuliginosus) were most abundant on flat, agricultural land, but less abundant in areas with high permitted dingo control. Euros (Osphranter robustus) were most abundant in rugged pastoral land with open vegetation, where permitted dingo control was high. While environmental variables are key drivers of landscape productivity and kangaroo populations, anthropogenic factors such as land use and permitted dingo control are strongly associated with kangaroo abundance.

Prospects for sustainable use of the pastoral areas of Australia’s southern rangelands: a synthesis

There is growing recognition of the need to achieve land use across the southern Australian rangelands that accommodates changing societal preferences and ensures the capacity of future generations to satisfy their own preferences. This paper considers the prospects for sustainable use of the pastoral lands based either on continued grazing or emerging, alternative land uses. After an overview of the southern rangelands environment, the status of the pastoral industry, its environmental impacts, and key issues for pastoral management, we propose four principles and 19 associated guidelines for sustainable pastoralism. Although some continued withdrawal of land from pastoralism is anticipated, we expect that pastoralism will continue throughout much of the region currently grazed, particularly in the higher rainfall environments in the east. Within these areas, sustainable pastoral land use should be achievable by the application of four broad management principles, as follows: (1) manage grazing within a risk management framework based on the concept of tactical grazing, (2) develop infrastructure to allow best management of both domestic and non-domestic grazing pressure, (3) incorporate management of invasive native scrub, where required, into overall, ongoing property management and (4) manage grazing to enhance biodiversity conservation at landscape scale. Application of these principles and guidelines will require the development of appropriate policy settings, particularly in relation to kangaroo management, climate change, and natural resource governance, together with innovative approaches to research, development and extension. Policy development will also be required if the new industry of carbon sequestration is to deliver socio-ecological benefits without perverse outcomes. Other emerging industries based on renewable energy or ecosystem services appear to have considerable potential, with little risk of adverse ecological consequences.

Expansion of Vertebrate Pest Exclusion Fencing and Its Potential Benefits for Threatened Fauna Recovery in Australia

The global effort to conserve threatened species relies heavily on our ability to separate these species from the processes that threaten them, and a common tool used for this purpose is exclusion fencing. In Australia, pest animal exclusion fencing has been repeatedly used on conservation land on a small scale to successfully exclude introduced predators and competitors from threatened native fauna populations. However, in recent years, "cluster fencing" on agricultural land has re-emerged on a large scale and is used by livestock producers seeking to reduce predation losses by dingoes (Canis familiaris) and manage total grazing pressure from native and introduced herbivores, including red kangaroos (Osphranter rufus). Given that the primary threats to at-risk native fauna are also predation and overgrazing, there may be potential for cluster fencing on livestock land to achieve additional fauna conservation benefits. Understanding the amount, location and potential conservation value of cluster fenced livestock land is critical for determining how these areas might contribute to broader threatened fauna recovery goals. Drawing from publicly available databases maintained by the Australian Government, we assessed the spatial overlap of threatened species' distributions with 105 cluster fences erected in Queensland since 2013, which cover 65,901 km² of land. These cluster fenced areas represent 18 biogeographic subregions and may contain 28 extant threatened mammals, birds and reptiles including 18 vulnerable species, 7 endangered species and 3 critically endangered species. An average of nine threatened species or their habitats were identified per cluster, and over three quarters (78.6%) of these species face at least one threat that is being mitigated within clusters. The true status of threatened and pest species within clusters is largely unknown or unrecorded in most cases, but some examples of pest eradication and threatened species recovery are already emerging. Given the vast size of the cluster fenced estate, the many different biomes and species that it represents and the nature of the threats being removed within these fenced areas, we contend that agricultural cluster fencing may offer an unprecedented opportunity to advance threatened fauna conservation goals for some species at scales previously thought impossible and should be a research priority for threatened species managers.

Prospects for ecologically and socially sustainable management of total grazing pressure in the southern rangelands of Australia

Numerous large herbivore species, both native and exotic, share the southern Australian rangelands with domestic livestock, which often account for only about half of the total grazing pressure. Although each presents its individual challenge to landholders, the management of kangaroos is a key component of ecologically sustainable management of the region because (a) they represent a significant component of the non-domestic grazing pressure, particularly in areas from which dingos and wild dogs have been (partially) removed; (b) commercial harvesting, the means of control that has the highest social acceptability, has been rendered ineffective by the actions of activist groups and market closure due to food safety concerns; (c) the task is largely beyond the capacity of individual landholders; and (d) the same constraints do not apply to other non-domestic components of total grazing pressure. Management of total grazing pressure, and particularly kangaroos, currently represents a case of market failure because the level of management that can be expected of landholders is not consistent with public expectations for resource conservation and animal welfare. Several avenues are available by which kangaroo management could be advanced to achieve both public and private benefits. These include adoption of an active, adaptive management approach to the kangaroo population, establishment of arrangements that will shift the general perception of kangaroos from pest to resource, development of an appropriate incentive framework to achieve desirable landscape outcomes, and continued evaluation of the benefits and costs of cluster fencing. These initiatives require both a greater commitment from governments to address the market failure and a proactive stance by industry to engage stakeholders, self-regulate, and objectively demonstrate environmental and animal welfare credentials.

Macropods, feral goats, sheep and cattle: 1. Equivalency in how much they eat

The extent to which goats and cattle eat equivalent amounts of forage as sheep has been based on their maintenance energy requirements (MERs) relative to a 50kg wether or dry ewe, known as a dry sheep equivalent (DSE). As such, a 50kg goat was considered 1 DSE and a 450kg steer as 7–8 DSE. In comparison, the DSE of macropods has been based on their basal metabolic rate (BMR) or energy expenditure of grazing (EEg) relative to those of sheep, with a 50kg macropod thought to be 0.7 and 0.45 DSE respectively. Based on published energy requirements of goats, macropods and cattle relative to sheep, their DSE values are estimated to be 1.2, 1.0 and 7.6 respectively. However, relative energy requirements may not be the same as relative dry matter intakes (DMIs), due to differences in forage quality, the structure of digestive tracts and selective foraging capabilities. Allometric equations that predict DMI were developed from published liveweights and intakes of sheep, goats, macropods and cattle. Given DMIs when fed high-quality forage, a 50kg goat was 1 DSE, a 50kg macropod was 0.7 DSE and a 450kg steer was 7.6 DSE. Their DMIs were depressed by 35–50% when fed low-quality forage, but a goat remained as 1 DSE, macropods increased to 1.0 DSE and cattle increased to 8.3 DSE. The capacity of macropods to maintain relatively higher DMIs of low-quality forage than sheep is probably due of their faster digesta passage rates and more expandable stomachs. These DMIs of animals provided ad-libitum quantities of similar forages in small pens are likely to differ from their DMIs when selectively grazing heterogeneous rangeland pastures. Under these conditions, sheep select higher-quality diets than cattle, and kangaroos select higher-quality diets than sheep, which increase the relative DMIs of the smaller herbivores. For this reason, a 50kg macropod is likely to be 1 DSE and consume twice as much forage than previously assumed.