Megan Star1, John Rolfe2, Giselle Whish1, and Miriam East1
1 Queensland Department of Agriculture, Fisheries and Forestry
Recent research has identified that poor water quality is having negative impacts on the health of the GBR. The prime determinant for the changes in water quality entering into the GBR has been attributed to the grazing industry, for sediment pollutants, and sugarcane for nutrient pollutants. The focus of this report is the trade-offs that occur in the grazing industry between land types, land condition, grazing pressure, economic implications and subsequent sediment emissions.
The report employs a bioeconomic model methodology to understand the biophysical and economic trade-offs for twelve land types in the Fitzroy, Burdekin and Herbert basins. The twelve land types explored in the report were black basalt, brigalow blackbutt, coolibah floodplains, goldfields, loamy alluvial, narrow leaved ironbark on deeper soils, narrow leaved ironbark on shallower soils, narrow leaved woodlands, open downs, red basalt, silver leaved ironbark and silver leaved ironbark on duplex.
Bioeconomic modelling captures the biophysical aspects of grazing production systems such as pasture growth, pasture species composition, sediment exported, and subsequent animal growth. The model then and integrates these variables into an economic framework which allows enterprise, sales, variable costs and subsequent profit to be estimated. To allow for climate variability, the model has 20 random start years followed by 20 consecutive years, capturing the profits and resulting sediment losses.
The results of the bioeconomic modelling highlighted the importance of the inherit productivity of the land type, land condition and tree basal area. Land types with poor land condition and of low productivity provided the greatest opportunity for low cost sediment reductions. Understanding the economically optimal grazing pasture utilisation rate provided insights into the policy mechanisms required for sediment reductions.
The report further informs the trade-offs between grazing pressure, economic implications and subsequent sediment exported. A key contribution is measured outcomes of investments, highlighting the efficient allocation of public funds for incentives and extension programs. It addresses a key criticism of past natural resource management programs through providing measured outcomes and through understanding the relationship between the biophysical and economic factors.