The aim of this report was to understand the causes of major episodes of degradation and recovery in Australia's pastoral rangelands, so that the community might better prepare for the future. A dominant feature of the eight episodes studied was the severe and extended nature of the drought periods. However, from our review, we concluded that other non-climatic factors contributed to the observed degradation. In some cases, the drought period revealed the damage already done in terms of the loss of desirable perennial vegetation (grasses and shrubs) and surface soil protection. This damage was the result of the over-expectation, by some graziers and governments, of the stocking rate that the resource could carry both in and out of drought. To some extent this over-expectation was falsely reinforced by relatively short periods (approximately five years) of above-average rainfall. In some cases, rapid declines in commodity prices contributed to the economic pressure to stock with too many animals.
The property histories highlighted that sustainable and profitable use of the rangelands is possible. However, the histories also documented the difficulties encountered during the first experience of severe and extended drought. These histories raised the question - does every new owner or manager have to learn from the painful experience of over-expectation of carrying capacity? The challenge for rangeland science is to provide and communicate the knowledge gained from hard-won grazier experience, and the understanding emerging from climate and ecological research. The episodes described here indicate that such knowledge is as important as skills in pasture management, animal husbandry and financial management.
Over the last decade, projects in cooperation with the grazing industry have addressed (and are continuing to address) the issue of sustainable grazing management and the extrapolation of successful grazier experience (e.g. Johnston et al. 2000). However, there remain major information and knowledge gaps that will have to be addressed if we are to prevent the next degradation episode. Systems for monitoring rangeland condition especially vegetation and soil cover are being put in place so as to provide `near real-time' resource assessment and alerts of increased risk of degradation. However, our review indicates that prevention of degradation will require a more timely reduction in numbers of livestock and other herbivores based on better risk assessment of the likelihood of extended drought periods. Our review of the current understanding of climate drivers of rangeland rainfall (and temperature) provided a tantalising glimmer of what might be possible at longer time scales (e.g. Power et al. 1999, White et al. 2003) than the current three-monthly outlooks.
The rapid growth in knowledge in climate science, fuelled in part by a desperate race to understand current climate trends and anticipate the impacts of future climate change, has not yet been regarded as mature enough to be included in operational climate forecasting systems for rangeland regions. Hence research to improve mechanistic understanding, skill and lead time is a high priority. Nevertheless, the initial understanding of El Niño-Southern Oscillation and other factors ( e.g. Indian Ocean sea surface temperatures) has underpinned current operational forecasting systems and community understanding since the late 1980s. The continuing use and availability of knowledge of historical climate variability and climate forecasts at least challenges graziers, their advisers, and governments to better manage for future climate variability to avoid repeating the mistakes of the past.
Last updated 16 February 2016