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Learning from history: preventing future land and pasture degradation under climate change.

McKeon, G.M., Dr.; Ph.: (07) 3896 9548; Fax: (07) 3896 9606; greg.mckeon@dnr.qld.gov.au

Research organisation: Climate Impacts and Grazing Systems Group, Queensland Department of Natural Resources, 80 Meiers Road, Indooroopilly Brisbane Qld 4068.

Collaborators:

QDNR (M. Silburn), QDPI (D. Orr, P. O'Reagain, P. Johnston, D. Phelps, M. Quirk), CSIRO Division of Wildlife & Ecology (M. Stafford Smith, S.M. Howden, N.O.J. Abel), CSIRO Division of Atmospheric Research (P. Whetton), CSIRO Division of Tropical Agriculture (A.J. Ash), NSW Division of Land and Water Conservation (R. Richards), South Australian Department of Environment, Heritage and Aboriginal Affairs (R.Tynan), WA Agriculture (I. Watson), Bureau of Meteorology Research Centre (N. Nicholls)

Sponsors: Environment Australia; Australian Greenhouse Office

Objectives:

The history of Australia's rangelands includes several major degradation events. The events provide an opportunity to learn from history so that the mistakes can be avoided in the future. These events include major episodes of climatic variability and the mismanagement of grazing pressure resulted in severe land and vegetation degradation. There is a clear need to understand the interaction of climate and management to evaluate climate change scenarios.

The objectives of the project are therefore to:

1. model historical degradation events in Australia's grazing lands;

2. use these models to evaluate the causes of such events including the interaction of climate variability and grazier perceptions of climate;

3. evaluate future climate change scenarios; and

4. develop adaptation strategies for the future.

We have concentrated on six events in the native pastures and shrublands of Australia:

1. south-west Queensland in the 1960s;

2. north-east Queensland in the 1980s;

3. south-east Queensland in the 1870s;

4. north-east South Australia and far western Queensland in the 1930s;

5. Gascoyne catchment in Western Australia in the 1930s; and

6. western New South Wales in the 1890s.

Methodology:

Document historical degradation events using published sources, oral history and reported animal statistics (eg shire or police district stock numbers). Modify existing models (developed in Rural Industries Research and Development Corporation project 124A) to include additional processes such as germination and establishment of woody weeds and annual pasture weeds. Use the models of land and pasture degradation to simulate each degradation event. Determine the combination of seasonal climate and stock management most likely to have caused degradation and examine historical climate record for frequency of such events. It is expected that the sequence is a series of good years followed by back to back intense droughts. Examine with simulation models to what extent ENSO-based forecasts could have reduced degradation. Evaluate output from GCM simulations of climate change to determine future frequency of these events. Incorporate the methodology in the existing Queensland and National Drought Alert system to provide early warning of the risk of degradation. Communicate the case study methodology and results to other States and develop collaborative proposals to seek funding to repeat this analysis in other States. Communicate results through Aussie GRASS project.

Progress:

The project has documented the role of climate variability in historical land and pasture degradation. It has developed general quantitative strategies from successful grazier experience to manage climate and shown how these strategies might be used to adapt to climate change. The project, when completed, will form the basis for policy recommendation on managing future climate change to prevent resource degradation.

  • Over 12 degradation events have been documented.
  • The interaction of climate variability and grazing pressure has been described.
  • Models of vegetation change and soil loss have been developed.
  • General safe stocking rate models as a function of climate have been constructed for Queensland based on grazier experience and expert opinion.
  • Effects of CO2 on tropical grass growth have been modelled.
  • Simulations of change in carrying capacity have been conducted for a range of climate change/CO2 scenarios.
  • Adaptation strategies using grazing management principles and seasonal forecasting have been evaluated in simulation studies.

Period: starting date 1996-07; 1999-06

Status: ongoing

Keywords: cattle; climate change; grazing management; land degradation; rangelands; sheep

Publications:

Ash, A.J., O'Reagain, P.J., McKeon, G.M. and Stafford Smith, M. (1998). Managing Climate Variability in Grazing Enterprises: A Case Study for Dalrymple Shire. The Symposium on Applications of Seasonal Climate Forecasting in Agricultural and Natural Ecosystems, The Australian Experience.

Carter, J.O., Day, K.A., Brook, K.D., Hall, W.B., McKeon, G.M. and Young, R.A. (1997). Aussie GRASS: Australian Grassland and Rangeland Assessment by Spatial Simulation, The Symposium on Applications of Seasonal Climate Forecasting in Agricultural and Natural Ecosystems; The Australian Experience, Volume of Abstracts, pp. 35-36, Brisbane, Australia, 10th-13th November.

Hall, W.B., McKeon, G.M., Carter, J.O., Day, K.A., Howden, S.M., Scanlan, J.C., Johnston, P.W. and Burrows, W.H. (in press). Climate Change in Queensland's Grazing Lands: II. An assessment of the impact on animal production from native pastures. The Rangeland Journal.

McKeon, G.M., Hall, W.B., Crimp, S.J., Howden, S.M., Stone, R.C. and Jones, D.A. (in press). Climate Change in Queensland's Grazing Lands: I. Approaches and climatic trends. The Rangeland Journal.

Stafford Smith, M., Buxton, R., McKeon, G.M. and Ash, A. (submitted). Seasonal Climate Forecasting and the Management of Rangelands: Do Production Benefits Translate into Enterprise Profits? The Symposium on Applications of Seasonal Climate Forecasting in Agricultural and Natural Ecosystems, The Australian Experience.

 

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