Global change impacts on native pastures in south-east Queensland, Australia

Howden, S. M.; McKeon, Greg; Walker, L.; Carter, J.O.; Conroy, Jann P.; Day, K. A.; Hall, W. B.; Ash, Andrew; Ghannoum, Oula

doi:10.1016/s1364-8152(98)00082-6

Cited by 39 publications

(19 citation statements)

References 33 publications

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“…The general physiological effects of reduced transpiration rate, slower decline in soil moisture, increased deep drainage, and increased transpiration and radiation use efficiencies are well known (Howden et al , 1999aMorgan et al 2004). Field trials using the FACE methodology (e.g.…”

Section: Co 2 Effectsmentioning

confidence: 99%

“…In this simulation example we used previous estimates of plant response to increased CO 2 Howden et al 1999aHowden et al , 1999bCrimp et al 2002). For CO 2 increase, pasture parameters (radiation use efficiency, potential regrowth, transpiration use efficiency, yield for 50% cover and nitrogen uptake per 100 mm of transpiration) were changed for C 3 and C 4 pasture communities.…”

Section: Simulating the Impact Of Increasing Comentioning

confidence: 99%

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Climate change impacts on northern Australian rangeland livestock carrying capacity: a review of issues

McKeon¹,

Stone²,

Syktus³

et al. 2009

Rangel. J.

213

136

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Grazing is a major land use in Australia’s rangelands. The ‘safe’ livestock carrying capacity (LCC) required to maintain resource condition is strongly dependent on climate. We reviewed: the approaches for quantifying LCC; current trends in climate and their effect on components of the grazing system; implications of the ‘best estimates’ of climate change projections for LCC; the agreement and disagreement between the current trends and projections; and the adequacy of current models of forage production in simulating the impact of climate change. We report the results of a sensitivity study of climate change impacts on forage production across the rangelands, and we discuss the more general issues facing grazing enterprises associated with climate change, such as ‘known uncertainties’ and adaptation responses (e.g. use of climate risk assessment). We found that the method of quantifying LCC from a combination of estimates (simulations) of long-term (>30 years) forage production and successful grazier experience has been well tested across northern Australian rangelands with different climatic regions. This methodology provides a sound base for the assessment of climate change impacts, even though there are many identified gaps in knowledge. The evaluation of current trends indicated substantial differences in the trends of annual rainfall (and simulated forage production) across Australian rangelands with general increases in most of western Australian rangelands (including northern regions of the Northern Territory) and decreases in eastern Australian rangelands and south-western Western Australia. Some of the projected changes in rainfall and temperature appear small compared with year-to-year variability. Nevertheless, the impacts on rangeland production systems are expected to be important in terms of required managerial and enterprise adaptations. Some important aspects of climate systems science remain unresolved, and we suggest that a risk-averse approach to rangeland management, based on the ‘best estimate’ projections, in combination with appropriate responses to short-term (1–5 years) climate variability, would reduce the risk of resource degradation. Climate change projections – including changes in rainfall, temperature, carbon dioxide and other climatic variables – if realised, are likely to affect forage and animal production, and ecosystem functioning. The major known uncertainties in quantifying climate change impacts are: (i) carbon dioxide effects on forage production, quality, nutrient cycling and competition between life forms (e.g. grass, shrubs and trees); and (ii) the future role of woody plants including effects of fire, climatic extremes and management for carbon storage. In a simple example of simulating climate change impacts on forage production, we found that increased temperature (3°C) was likely to result in a decrease in forage production for most rangeland locations (e.g. –21% calculated as an unweighted average across 90 locations). The increase in temperature exacerbated or reduced the effects of a 10% decrease/increase in rainfall respectively (–33% or –9%). Estimates of the beneficial effects of increased CO2 (from 350 to 650 ppm) on forage production and water use efficiency indicated enhanced forage production (+26%). The increase was approximately equivalent to the decline in forage production associated with a 3°C temperature increase. The large magnitude of these opposing effects emphasised the importance of the uncertainties in quantifying the impacts of these components of climate change. We anticipate decreases in LCC given that the ‘best estimate’ of climate change across the rangelands is for a decline (or little change) in rainfall and an increase in temperature. As a consequence, we suggest that public policy have regard for: the implications for livestock enterprises, regional communities, potential resource damage, animal welfare and human distress. However, the capability to quantify these warnings is yet to be developed and this important task remains as a challenge for rangeland and climate systems science.

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Section: Co 2 Effectsmentioning

confidence: 99%

Section: Simulating the Impact Of Increasing Comentioning

confidence: 99%

Climate change impacts on northern Australian rangeland livestock carrying capacity: a review of issues

McKeon¹,

Stone²,

Syktus³

et al. 2009

Rangel. J.

213

136

View full text Add to dashboard Cite

show abstract

“…Global warming and sustainability issues can be considered at a large number of levels as well as related to several environmental conditions. According to the IPCC 2 forecast, glo- bal ambient temperature is likely to increase up to 5ºC until the end of this century affecting in an overall way agricultural and animal production (Bates et al, 1996;Brklacich et al, 2000;Chiotti and Johnston, 1995;CIG, 1996;IPCC 2001IPCC , 2001aIPCC, 2007;Specht and Specht, 1995) and this kind of global change leads to broad shifts in socio-economic systems Harrington and Lu, 2002;Howden et al, 1999;McCown et al, 1981;Mott et al, 1985;Stafford Smith and Foran, 1992;Topp and Doyle, 1996;), as well as bio-physical changes (Foran and Stafford Smith, 1991;Graetz et al, 1988;Marcelino, 2007). Possible variation in agricultural yield facing global warming has been established Siqueira et al, 1994;Stafford Streck and Alberto, 2006) and trends of modification in rainfall indexes leading to droughts not only in the Cerrado area, but also expanding towards the Amazon basin, have been reported (Marcelino et al, 2006;Marcelino, 2007;Sombroek, 2001).…”

Section: Impact Of Global Warming On Beef Cattle Production Cost In Bmentioning

confidence: 99%

Impact of global warming on beef cattle production cost in Brazil

2015

ASABE 1st Climate Change Symposium: Adaptation and Mitigation

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Global warming is affecting agribusiness in its economic aspects. Therefore, the prediction of the evolution of Brazilian beef cattle production cost was made using the IPCC forecast scenario for global warming. The methodology consisted of two steps: (i) the development of a fuzzy model that estimated the grazing land capacity (RP) decrease risk as a function of the changes in the average total rain index, air temperature and increase in extension of the dry season; and (ii) the design of an algorithm for predicting the decrease in production as function of the RP fuzzy model, that results in the impact in beef cattle productivity, and consequent increase in production costs. Historical environmental data from important producing counties in the Cerrado were organized and a set of fuzzy Gaussian functions were developed, and three possible settings (optimistic, medium and pessimistic) were considered. The decrease in beef cattle productivity was estimated using the losses in production due to the increase in air temperature and vulnerability of pasture capacity. The boundary settings for the total increase of production cost scenario used the number of animals per area of grazing land, the adoption of grain supplement and its future scenario; and the result output function pointed to a threshold within a variation from an increase in production cost of 80% (optimistic) to 160% (pessimistic). Under the optimistic scenario the total cost of Brazilian beef cattle production in the Cerrado became near to US$ 2.88 kg -1 , while in the pessimistic scenario this cost reached US$ 4.16 kg -1 , challenging the international competitiveness of this economic segment. Key words: dry season, environmental temperature, fuzzy simulation, mathematical modeling Impacto do aquecimento global no custo de produção de carne bovina no Brasil RESUMO: O aquecimento global afeta o agronegócio em seus aspectos econômicos. Foi feita previsão da evolução do custo de produção de carne bovina brasileira usando a predição de aquecimento global do IPCC. A metodologia consistiu de duas etapas: (i) o desenvolvimento de modelo fuzzy que estimou o risco de decréscimo da capacidade de pastagens (RP) em função das mudanças no índice pluviométrico total, na temperatura do ar e na extensão da estação de seca; e (ii) o desenvolvimento de um algoritmo para predição do decréscimo da produção em função de um modelo fuzzy de RP que resulte no impacto na produtividade bovina de corte e conseqüente aumento no custo de produção. Foram organizados os dados históricos de fatores ambientais dos municípios importante produção no Cerrado e um conjunto de funções Gaussianas fuzzy foi desenvolvido e três estimativas possíveis (otimista, média e negativa) foram consideradas. O decréscimo na produtividade do gado foi estimado usando as perdas de produção devido ao acréscimo da temperatura bem como da vulnerabilidade da capacidade de pastagem. O estabelecimento dos limites para o cenário do acréscimo do custo de produção usou o número de unidade animal por ár...

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“…These studies have employed mechanistic pasture growth and animal production models to determine how combinations of changes in CO 2 , temperature and rainfall influence forage production and livestock carrying capacity (Hall et al 1998;Howden et al 1999b;White et al 2003;Cullen et al 2009;McKeon et al 2009). The studies have demonstrated the effects of CO 2 fertilisation on pasture growth in both C 3 and C 4 pasture communities (Cullen et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Interacting effects of vegetation, soils and management on the sensitivity of Australian savanna rangelands to climate change

Webb

Stokes

Scanlan³

2011

Climatic Change

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There is an increasing need to understand what makes vegetation at some locations more sensitive to climate change than others. For savanna rangelands, this requires building knowledge of how forage production in different land types will respond to climate change, and identifying how location-specific land type characteristics, climate and land management control the magnitude and direction of its responses to change. Here, a simulation analysis is used to explore how forage production in 14 land types of the north-eastern Australian rangelands responds to three climate change scenarios of +3°C, +17% rainfall; +2°C, −7% rainfall; and +3°C, −46% rainfall. Our results demonstrate that the controls on forage production responses are complex, with functional characteristics of land types interacting to determine the magnitude and direction of change. Forage production may increase by up to 60% or decrease by up to 90% in response to the extreme scenarios of change. The magnitude of these responses is dependent on whether forage production is water or nitrogen (N) limited, and how climate changes influence these limiting conditions. Forage production responds most to changes in temperature and moisture availability in land types that are water-limited, and shows the least amount of change when growth is restricted by N availability. The fertilisation effects of doubled atmospheric CO 2 were found to offset declines in forage production under 2°C warming and a 7% reduction in rainfall. However, rising tree densities and declining land condition are shown to reduce potential opportunities from increases in forage production and raise the sensitivity of pastures to climate-induced water stress. Knowledge of these interactions can be applied in engaging with stakeholders to identify adaptation options.

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Global change impacts on native pastures in south-east Queensland, Australia

Cited by 39 publications

References 33 publications

Climate change impacts on northern Australian rangeland livestock carrying capacity: a review of issues

Climate change impacts on northern Australian rangeland livestock carrying capacity: a review of issues

Impact of global warming on beef cattle production cost in Brazil

Interacting effects of vegetation, soils and management on the sensitivity of Australian savanna rangelands to climate change

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