How much organic carbon could the soil store? The carbon sequestration potential of Australian soil

Soil is a huge carbon (C) reservoir, but where and how much extra C can be stored is unknown. Current methods to estimate the maximum amount of mineral-associated organic carbon (MAOC) stabilized in the fine fraction (clay + silt,< 20 μm $$ <20\;\upmu \mathrm{m} $$ ) fit through the MAOC versus clay + silt relationship, not their maxima, making their estimates more uncertain and unreliable. We need a function that 'envelopes' that relationship. Here, using 5089 observations, we estimated that the uppermost 30 cm of Australian soil holds 13 Gt (10-18 Gt) of MAOC. We then fitted frontier lines, by soil type, to the relationship between MAOC and the percentage of clay + silt to estimate the maximum amounts of MAOC that Australian soils could store in their current environments, and calculated the MAOC deficit, or C sequestration potential. We propagated the uncertainties from the frontier line fitting and mapped the estimates of these values over Australia using machine learning and kriging with external drift. The maps show regions where the soil is more in MAOC deficit and has greater sequestration potential. The modelling shows that the variation over the whole continent is determined mainly by climate, linked to vegetation and soil mineralogy. We find that the MAOC deficit in Australian soil is 40 Gt (25-60 Gt). The deficit in the vast rangelands is 20.84 Gt (13.97-29.70 Gt) and the deficit in cropping soil is 1.63 Gt (1.12-2.32 Gt). Management could increase C sequestration in these regions if the climate allowed it. Our findings provide new information on the C sequestration potential of Australian soils and highlight priority regions for soil management. Australia could benefit environmentally, socially and economically by unlocking even a tiny portion of its soil's C sequestration potential.

Developing sustainable land-use patterns at watershed scale using nexus of soil, water, energy, and food

Aside from the many services that soil provides, it also stores water and makes it available to crops, which is critical for food security. However, the necessity of further studies for overcoming the existing gap in relation to the role of soil in the water, energy, and food nexus system has been preoccupying the experts and specialists around the world for some time. In this sense, the balance between many key ecosystem components based on the Soil, water, energy, and food (SWEF) nexus framework is one of the key characteristics of holistic and accommodative watershed management systems. To the best of our knowledge, the watershed scale is used as a planning unit for the first time in the current study to construct a conceptual model for adaptive management of optimum land-use/cover allocation using SWEF. The method was then used for the Shazand Watershed, Iran. Numerous metrics, such as soil erosion, soil organic carbon (SOC), water and energy use, mass efficiency, and economic efficiency, were investigated. Finally, a compound indicator was used to generate the SWEF nexus index (SWEFNI) for various land-uses/crops for the node year 2014. SWFENI ranged from 0.19 (worst) for rangeland to 0.78 (best) for almond plantations, according to the findings. The study's present approach may be tested worldwide.

Empowering Indigenous natural hazards management in northern Australia

Northern Australia is prone to recurring severe natural hazards, especially frequent cyclones, flooding, and extensive wildfires. The region is sparsely populated (≪ 0.5 persons km^-2), with Indigenous (Aboriginal) residents comprising 14% of the population, and typically the majority in remote regions. Despite national policy committed to addressing emergency management (EM) in vulnerable Indigenous communities, implementation remains unfunded. We synthesise participatory intercultural research conducted over seven years exploring core challenges, opportunities and potential solutions towards developing effective EM partnerships. Similar EM engagement and empowerment issues face First Nations and local communities in many international settings. In search of solutions, we explore developing effective partnership arrangements between EM agencies and culturally diverse Indigenous communities. Observing that government already provides substantial investment in cultural and natural resource management programmes conducted by over 150 Indigenous Ranger Groups (IRGs) nationally, we demonstrate that expansion of IRG roles to incorporate EM community engagement and service delivery can provide multiple cost-effective community and business development benefits for many remote communities.

Are canid pest ejectors an effective control tool for wild dogs in an arid rangeland environment?

Abstract Context Wild dogs are a significant pest species of livestock production and native wildlife in Australia. A suite of control tools is used to mitigate predation impacts. Baiting with sodium fluoroacetate is the most commonly used control tool in Australia; however, its effectiveness can be reduced by interference by non-target species, and in some contexts by microbial degradation of the toxin. Canid pest ejectors (CPEs) are a mechanical device with an attractant ‘lure head’ designed to eject a lethal toxin into the mouth of canids pulling on the lure head. A range of lure heads can be used to attract canids to pull, and trigger CPEs. Aims We aimed to determine whether uptake of CPEs by wild dogs in an arid rangeland environment could cause a decline in a wild dog population. We also aimed to determine whether there are particular lure heads that increase the rate of CPEs being triggered by wild dogs. Methods We deployed one hundred CPEs over four sessions of control across three properties in the southern rangelands of Western Australia from 2018 to 2020. Each session consisted of 2 months of CPE deployment with two different lure heads, totalling eight lure head types over the entire study. All CPEs were monitored using camera traps. Key results Wild dog density varied over the study period. In all four control sessions, a decrease in wild dog density was recorded (–46%, –5%, –13%, –38%). Wild dog activity events on camera and their interest in CPEs differed between sessions and lures (i.e. higher with scent-based lures). Non-target species did not interfere with CPEs significantly, despite a higher number of activity events by non-target species than wild dogs. Conclusions CPEs caused a reduction of 5–46% of wild dog density when deployed in the southern rangelands of Western Australia. Non-target interference was minimal when using CPEs for wild dog control. Implications Use of scent-based lures on felt lure heads is recommended for successful use of CPEs for wild dog control in arid rangeland environments. Future on-ground wild dog control should include CPEs as a complementary tool for the reduction of wild dog density.

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.

Building human capacity, capability and future leaders for Australia’s rangelands

Maintaining a skilled, knowledgeable and adaptable workforce in Australian rangeland enterprises and research, development and extension/adoption (RD&amp;E/A) organisations is a varied and challenging task, compounded by trends of sustained losses of human capacity through senior retirements and short-term appointments over the last decade. Concerns for how to fill these gaps while gaining the skills and knowledge needed for a successful career and leadership roles were raised by students and young professionals in the World Cafe session and throughout Early Career workshops and activities at the 2019 Biennial Conference of the Australian Rangeland Society (ARS). This paper responds to these expressed information needs through drawing on literature, experiences shared by session participants, and existing ARS members currently working in the rangelands in diverse roles to provide insights into two main areas: (i) skills and knowledge for personal development and future success in the rangelands across three broad classes of occupation/careers (i.e. advisors, researchers, and producers), and (ii) skills and knowledge that will be expected of future leaders in the rangelands. We outline a variety of options for professional development in the early stage(s) of a career working on aspects of sustainable production systems and pathways to leadership throughout a career in the rangelands. We note the apparent lack of formal rangeland-specific education in Australia, and suggest that this is a major impediment to efforts to build skills and knowledge to ensure the viability of the livelihoods and the integrity of our rangelands. Finally, we believe that the ARS has the potential to play a more central role in inspiring interest and passion for the rangelands, in providing current information on (i) range science and management-relevant education and training opportunities in Australia and internationally, and (ii) leadership development and training opportunities; and in facilitating and supporting mentoring to develop and retain human capacity for a resilient future.

Nudging the narrative: heading in the 'right direction'

Lack of engagement with rangelands by the general public, politicians and some practitioners has led to policy failure and unsustainable practice. We argue that thinking in terms of cultural reciprocity with land will lead to greater sustainability of rangeland uses. Many grass-roots initiatives are already showing the way by working at the boundary of science, society and decision makers, involving everyone with a stake in the outcome and developing genuine collaboration and acceptance of diverse value systems.

Challenges, solutions and research priorities for sustainable rangelands

Australia’s rangeland communities, industries, and environment are under increasing pressures from anthropogenic activities and global changes more broadly. We conducted a horizon scan to identify and prioritise key challenges facing Australian rangelands and their communities, and outline possible avenues to address these challenges, with a particular focus on research priorities. We surveyed participants of the Australian Rangeland Society 20th Biennial Conference, held in Canberra in September 2019, before the conference and in interactive workshops during the conference, in order to identify key challenges, potential solutions, and research priorities. The feedback was broadly grouped into six themes associated with supporting local communities, managing natural capital, climate variability and change, traditional knowledge, governance, and research and development. Each theme had several sub-themes and potential solutions to ensure positive, long-term outcomes for the rangelands. The survey responses made it clear that supporting ‘resilient and sustainable rangelands that provide cultural, societal, environmental and economic outcomes simultaneously’ is of great value to stakeholders. The synthesis of survey responses combined with expert knowledge highlighted that sustaining local communities in the long term will require that the inherent social, cultural and natural capital of rangelands are managed sustainably, particularly in light of current and projected variability in climate. Establishment of guidelines and approaches to address these challenges will benefit from: (i) an increased recognition of the value and contributions of traditional knowledge and practices; (ii) development of better governance that is guided by and benefits local stakeholders; and (iii) more funding to conduct and implement strong research and development activities, with research focused on addressing critical knowledge gaps as identified by the local stakeholders. This requires strong governance with legislation and policies that work for the rangelands. We provide a framework that indicates the key knowledge gaps and how innovations may be implemented and scaled out, up and deep to achieve the resilience of Australia’s rangelands. The same principles could be adapted to address challenges in rangelands on other continents, with similar beneficial outcomes.

A narrative to support the future of the Australian Outback

Stories matter: as powerful frames for policy and public understanding, but the current narratives about Outback Australia are both confused and often negative. We illustrate this power of stories, including how deliberate framing and story-telling to create a better narrative on some rangeland issues has had positive policy outcomes. Moving to a more intuitive name is one key issue – we suggest that talking of the ‘Modern Outback’ is a powerful change in this regard. We then draw on discussions to provide a set of guiding principles for how to frame writings about the Outback, and give an example of their use.

A call for collaboration: linking local and non-local rangeland communities to build resilience

The people who live in Australia’s rangelands are vital for maintaining natural systems, agricultural production, infrastructure for tourism and many services and products which benefit the nation. However, the number of people living within many rangeland regions is declining, services are being withdrawn and resilience undermined. Social capital is an important concept within the resilience literature. Bonding social capital is based strong ties within relatively homogenous local groups, bridging social capital is based on ties between more diverse local groups and linking social capital is based on ties between local and external groups. Within the rangelands, there are often strong bonding and bridging social capitals based on internal social and formal connections, but gaps in linking social capital due to weak or imbalanced connections with external groups and organisations. There is evidence that all three social capitals are needed for regional resilience, and the gap in linking is thus a key issue. People who live outside the rangelands can help rebuild this resilience by linking their skills, knowledge and expertise with local groups and communities. Many city-based scientists, policy makers, influencers and other professionals work in and have empathy for the rangelands. By connecting meaningfully with local groups such as Landcare, service clubs, philanthropic groups or Indigenous Rangers, they would find many benefits to their own endeavours through improved policies, knowledge and service delivery. Central-western Queensland is provided as an example where many such mutual benefits and networks already exist, offering pathways for linking local residents with external experts. Current platforms offer opportunities for a greater range of external academic institutions and organisations to engage with locals, with everyone standing to gain.

Public attitudes to animal welfare and landholder resource limitations: implications for total grazing pressure management in the southern rangelands of Australia

Sustainable grazing in the nationally iconic southern rangelands of Australia requires landholders to actively manage the grazing pressure from both domestic livestock and non-domestic herbivores. Landholders have primary responsibility for controlling the non-domestic herbivores. In doing so, they must meet the Australian public’s expectations for resource conservation (mainly a public good) and animal welfare. Governments are also involved in the management of non-domestic herbivores via native and feral animal legislation and control programs. The Australian public will not accept cruelty to animals, perceived or otherwise. In this paper we explore the challenges faced by landholders in their attempts to manage the grazing pressure from native herbivores, particularly kangaroos, feral goats and feral pigs, while meeting the Australian public’s expectations for animal welfare. Landholders typically live on extensive properties and their capacity to manage these is influenced by high climate variability, low labour availability, commodity price fluctuations and limited capital available for investment in new technologies. The additional requirement to reduce the grazing pressure from kangaroos, feral goats and feral pigs is a significant burden on already time-poor landholders. Hence, there is a critical disparity between landholders’ capacity and their responsibility to effectively manage the non-domestic herbivores on their properties. We suggest that current expectations of landholders to deliver public benefits by publicly acceptable practices are unreasonable. Further, we suggest that governments should accept more responsibility for managing non-domestic grazing pressure. The concept of duty of care to land management provides a means by which a more appropriate division of responsibilities between landholders and government could be achieved to ensure that valued attributes of this iconic Australian landscape are retained.