Rangeland profitability in the northern Gulf region of Queensland: understanding beef business complexity and the subsequent impact on land resource management and environmental outcomes

The farm-gate value of extensive beef production from the northern Gulf region of Queensland, Australia, is ~$150 million annually. Poor profitability and declining equity are common issues for most beef businesses in the region. The beef industry relies primarily on native pasture systems and studies continue to report a decline in the condition and productivity of important land types in the region. Governments and Natural Resource Management groups are investing significant resources to restore landscape health and productivity. Fundamental community expectations also include broader environmental outcomes such as reducing beef industry greenhouse gas emissions. Whole-of-business analysis results are presented from 18 extensive beef businesses (producers) to highlight the complex social and economic drivers of management decisions that impact on the natural resource and environment. Business analysis activities also focussed on improving enterprise performance. Profitability, herd performance and greenhouse emission benchmarks are documented and discussed.

Comparing fixed and flexible stocking as adaptations to inter-annual rainfall variability in the extensive beef industry of northern Australia

Many beef producers within the extensive cattle industry of northern Australia attempt to maintain a constant herd size from year-to-year (fixed stocking), whereas others adjust stock numbers to varying degrees annually in response to changes in forage supply. The effects of these strategies on pasture condition and cattle productivity cannot easily be assessed by grazing trials. Simulation studies, which include feedbacks of changes to pasture condition on cattle liveweight gain, can extend the results of grazing trials both spatially and temporally. They can compare a large number of strategies, over long periods of time, for a range of climate periods, at locations which differ markedly in climate. This simulation study compared the pasture condition and cattle productivity achieved by fixed stocking at the long-term carrying capacity with that of 55 flexible stocking strategies at 28 locations across Queensland and the Northern Territory. Flexible stocking strategies differed markedly in the degree they increased or decreased cattle stocking rates after good and poor pasture growing seasons, respectively. The 28 locations covered the full range in average annual rainfall and inter-annual rainfall variability experienced across northern Australia. Constrained flexibility, which limited increases in stocking rates after good growing seasons to 10% but decreased them by up to 20% after poor growing seasons, provides sustainable productivity gains for cattle producers in northern Australia. This strategy can improve pasture condition and increase cattle productivity relative to fixed stocking at the long-term carrying capacity, and its capacity to do this was greatest in the semiarid rangeland regions that contain the majority of beef cattle in northern Australia. More flexible stocking strategies, which also increased stocking rates after good growing seasons by only half as much as they decreased them after poor growing seasons, were equally sustainable and more productive than constrained flexibility, but are often impractical at property and industry scales. Strategies with the highest limits (e.g. 70%) for both annual increases and decreases in stocking rates could achieve higher cattle productivity, but this was at the expense of pasture condition and was not sustainable. Constrained flexible stocking, with a 10% limit for increases and a 20% limit for decreases in stocking rates annually, is a risk-averse adaptation to high and unpredictable rainfall variability for the extensive beef industry of northern Australia. © Australian Rangeland Society 2016.

Seasonal and Species Variation of the Hepatotoxin Indospicine in Australian Indigofera Legumes as Measured by UPLC−MS/MS

Livestock industries have maintained a keen interest in pasture legumes because of the high protein content and nutritive value. Leguminous Indigofera plant species have been considered as having high feeding values to be utilized as pasture, but the occurrence of the toxic constituent indospicine in some species has restricted this utility. Indospicine has caused both primary and secondary hepatotoxicosis and also reproductive losses, but has only previously been determined in a small number of Indigofera species. This paper validates a high throughput ultra-performance liquid chromatography−tandem mass spectrometry (UPLC−MS/MS) method to determine indospicine content of various Indigofera species found in Australian pasture. Twelve species of Indigofera together with Indigastrum parviflorum plants were collected and analysed. Out of the 84 samples analyzed, *I. spicata contained the highest indospicine level (1003 ± 328 mg/kg DM, n = 4) followed by I. linnaei (755 ± 490 mg/kg DM, n = 51). Indospicine was not detected in 9 of the remaining 11 species, and at only low levels (<10 mg/kg DM) in 2 out of 8 I. colutea specimens and in 1 out of 5 I. linifolia specimens. Indospicine concentrations were below quantitation levels for other Indigofera spp. (I. adesmiifolia, I. georgei, I. hirsuta, I. leucotricha,* I. oblongifolia, I. australis and I. trita) and Indigastrum parviflorum. One of the more significant findings to emerge from this study is that the indospicine content of I. linnaei is highly variable (159 to 2128 mg/kg DM, n = 51), and differs across both regions and seasons. Its first re-growth after spring rain has a higher (p < 0.01) indospicine content than growth following more substantial summer rain. The species collected include the predominant Indigofera in Australia pasture, and of these, only *I. spicata and I. linnaei contain high enough levels of indospicine to pose a potential toxic threat to grazing herbivores.

Recent development and commercial adoption of legumes for heavy clay soils in Queensland

In previous chapters of this volume, various authors describe the development of herbaceous legumes for pastures on clay soils in Queensland until about the 1980s. Emphasis is on the collection and evaluation of the genus Desmanthus, given its relatively recent addition to agriculture and considerable potential for providing useful pasture legumes for clay soils, particularly in the seasonally dry areas of northern Australia. Other genera are also discussed, including early assessments of herbaceous legumes that were later developed for clay soils (Clitoria, Macroptilium and Stylosanthes). This chapter provides a summary of the development of herbaceous legumes for clay soils in Queensland from these earlier assessments until present. Beef cattle farming is the principal agricultural enterprise in seasonally dry areas of northern Australia, including large areas of clay soils in Queensland. Sown and naturally occurring grasses provide the key feed resource, and the inclusion of sown legumes can significantly improve live-weight gain and reproductive performance per unit area. Queensland has been the centre of development for legumes for clay soils in tropical and subtropical areas of Australia, mostly through assessing and developing plants held in the Australian Tropical Forages Genetic Resource Collection (ATFGRC) (now a component of the Australia Pastures Genebank (APG)). The systematic appraisal of genetic material for clay soils was a focus of well-resourced government research up to the early to mid-1990s, but declined thereafter as sown pasture research teams were dismantled and funding to maintain the ATFGRC declined. Cultivar development is now conducted by small government, private enterprise and university research teams that collaborate where possible. In recent studies the use of experienced researcher knowledge and old plant evaluation sites has been particularly valuable for identifying potentially useful material. Cultivars for long- and short-term pastures on clay soils have been developed to the level of commercial seed production for Desmanthus (five cultivars from four species with two cultivars (one composite) in current use), Clitoria ternatea (one cultivar), Macroptilium bracteatum (two) and Stylosanthes seabrana (two). Other potential cultivars of these species are currently in various stages of development. Each species has different production niches depending on climate, clay soil type and grazing strategy. Adoption of these cultivars is occurring but has variously been impeded by limited promotion, mismatch of seed supply and demand, and difficulty establishing legumes in pastures of some key grass species. Recent renewed investment by the Australian Beef Industry has seen revived government research into pasture legumes in Queensland and rejuvenation of the APG.

Bioeconomic modelling of woody regrowth carbon offset options in productive grazing systems

Agricultural land has been identified as a potential source of greenhouse gas emissions offsets through biosequestration in vegetation and soil. In the extensive grazing land of Australia, landholders may participate in the Australian Government’s Emissions Reduction Fund and create offsets by reducing woody vegetation clearing and allowing native woody plant regrowth to grow. This study used bioeconomic modelling to evaluate the trade-offs between an existing central Queensland grazing operation, which has been using repeated tree clearing to maintain pasture growth, and an alternative carbon and grazing enterprise in which tree clearing is reduced and the additional carbon sequestered in trees is sold. The results showed that ceasing clearing in favour of producing offsets produces a higher net present value over 20 years than the existing cattle enterprise at carbon prices, which are close to current (2015) market levels (~$13 t–1 CO2-e). However, by modifying key variables, relative profitability did change. Sensitivity analysis evaluated key variables, which determine the relative profitability of carbon and cattle. In order of importance these were: the carbon price, the gross margin of cattle production, the severity of the tree–grass relationship, the area of regrowth retained, the age of regrowth at the start of the project, and to a lesser extent the cost of carbon project administration, compliance and monitoring. Based on the analysis, retaining regrowth to generate carbon income may be worthwhile for cattle producers in Australia, but careful consideration needs to be given to the opportunity cost of reduced cattle income.

Pasture production and composition response after killing Eucalypt trees with herbicides in central Queensland

Clearing woodlands is practised world-wide to increase crop and livestock production, but can result in unintended consequences including woody regrowth and land degradation. The pasture response of 2 eucalypt woodlands in the central Queensland rangelands to killing trees with herbicides, in the presence or absence of grazing and regular spring burning, was recorded over 7 or 8 years to determine the long-term sustainability of these common practices. Herbage mass and species composition plus tree dynamics were monitored in 2 replicated experiments at each site. For 8 years following herbicide application, killing Eucalyptus populnea F. Muell. (poplar box) trees resulted in a doubling of native pasture herbage mass from that of the pre-existing woodland, with a tree basal area of 8.7 m2 ha-1. Conversely, over 7 years with a similar range of seasons, killing E. melanophloia F. Muell. (silver-leaved ironbark) trees of a similar tree basal area had little impact on herbage mass grown or on pasture composition for the first 4 years before production then increased. Few consistent changes in pasture composition were recorded after killing the trees, although there was an increase in the desirable grasses Dichanthium sericeum (R. Br.) A. Camus (Queensland bluegrass) and Themeda triandra Forssk. (kangaroo grass) when grazed conservatively. Excluding grazing allowed more palatable species of the major grasses to enhance their prominence, but seasonal conditions still had a major influence on their production in particular years. Pasture crown basal area was significantly higher where trees had been killed, especially in the poplar box woodland. Removing tree competition did not have a major effect on pasture composition that was independent of other management impositions or seasons, and it did not result in a rapid increase in herbage mass in both eucalypt communities. The slow pasture response to tree removal at one site indicates that regional models and economic projections relating to tree clearing require community-specific inputs.

An Investigation of the Impacts of Ponded Pastures on Barramundi and Other Finfish Populations in Tropical Coastal Wetlands

Objectives: 1) To document the extent of ponded pastures and other pondage systems in and adjacent to coastal wetlands on the central coast of Queensland. 2) To assess the movement, growth and survival of barramundi in ponded pastures. 3) To assess the utilisation by barramundi of ponded pastures and wetlands dominated by exotic grass species. 4) To identify appropriate wetland management strategies for facilitating barramundi movement and survival in ponded pastures and other pondage systems. 5) To document the species composition of finfish populations and their relative abundance in ponded pastures.

Interacción planta-animal en el contexto de sistemas productivos desarrollados en distintos ambientes ecológicos

El estudio de los factores que rigen los patrones espaciales de la distribución del pastoreo de los herbívoros domésticos es fundamental en la ecología y el manejo de los recursos naturales. Aunque los productores y profesionales realizan ajustes anuales o estacionales de la carga animal para influir en la preferencia animal por determinados ambientes de pastoreo y alcanzar un uso eficiente del recurso forrajero, el manejo de la distribución del ganado continúa siendo un gran desafío. La heterogeneidad de los ambientes de pastoreo tiene dimensión tanto espacial como temporal, lo cual impone desafíos en el entendimiento de los factores que influyen en las decisiones de selección de hábitat por parte del ganado. En esta contribución comenzamos revisando los modelos conceptuales actuales del comportamiento del ganado a grandes escalas. Luego, presentamos algunos resultados de estudios conducidos en diferentes ecosistemas contrastantes de Argentina y New Mexico (EEUU). Estos estudios desarrollados usando animales con y sin collares GPS contribuyen a mejorar gradualmente las decisiones de manejo de los pastizales. Finalmente, hacemos unas consideraciones breves relacionadas con el manejo del ganado en Ecuador que pueden contribuir a mejorar la sustentabilidad de los sistemas de producción ganaderos.

Dietary overlap between sympatric dingoes and feral cats at a semiarid rangeland site in Western Australia

Abstract. The diet of sympatric dingoes and feral cats was studied in the semiarid southern rangelands of Western Australia. A total of 163 scats were collected over a period of 19 months. Rabbit remains were the most common food item in cat scats, followed by reptiles, small mammals and birds. Macropod remains were the most common food item in dingo scats, followed by rabbits and birds. Dingo scats did not contain small mammal remains, and infrequently contained arthropod and reptile remains. Cat and dingo scats contained remains from 11 and six mammal species, respectively. Of the small mammals, cat scats contained rodent remains more frequently than those of dasyurids. Dietary diversity of cats was higher than for dingoes and dietary overlap between the two species was relatively low.