Managing Sources and Sinks of Greenhouse Gases in Australia’s Rangelands and Tropical Savannas

Abstract

Rangelands and savannas occupy 70% of the Australian continent and are mainly used for commercial grazing of sheep and cattle. In the center and north, where there are extensive areas of indigenous land ownership and pastoral production is less intensive, savanna burning is frequent. Greenhouse gas emissions from rangelands have been overwhelmingly from land clearing and methane production by livestock. Reductions in the rate of land clearing have substantially reduced Australia’s greenhouse gas emissions, but these have been controversial with the reduced potential pasture production being of concern to many land managers. Reductions in direct livestock emissions are possible through manipulation of the genetics, rumen flora, or diet of animals. However, the greatest potential benefit is a whole-property approach with improved animal husbandry and attention to other aspects of property management such as fossil fuel consumption. Focus on emissions per unit of land area is likely to have other ecological benefits for land condition and to capture the effects of changes in carbon stocks in vegetation and soils. In much of northern and central Australia, changes in settlement patterns have led to more frequent and intense fires than under indigenous management regimes before European settlement. The implementation of more benign regimes of savanna burning has great potential benefit for greenhouse abatement, biodiversity, and livelihoods of indigenous people in remote settlements.