Tim Parratt

The Institute of Wildlife Research
School of Biological Sciences
Heydon-Laurence Building A08
University of Sydney
NSW 2006

Tel: (61-2) 9351 3134
Fax: (61-2) 9351 4119

Current Research

There is a huge spatial and temporal variation in the distribution of biotic resources in the arid environment. The dramatic fluctuations in resource levels are thought to be driven primarily by rainfall, although it is now thought that fire also plays a significant role, especially in the hummock grasslands of inland Australia. Based on the ecological principal that events at the regional scale (rainfall and fire) will drive the local dynamics of producers (seeds), the overall study aim is to evaluate the roles of rainfall and fires in driving seed abundance in arid Australia.

The conceptual model is that there are two extremes; boom (high plant biomass and rodent eruptions), and bust ((low plant biomass, rodents scarce). Between these two extremes are several transitional states.

The first prediction is that peak rainfall events (>300mm over summer) will increase plant productivity and drive the system from bust towards a boom. Modest rainfall will lead to transitions only one state in the system, whilst prolonged drought will reverse this effect and the system will decrease in diversity to the lower states.

The second prediction is that extensive wildfire will reset the system to low plant biomass (bust) and if followed by significant rainfall then productivity will increase and transitions to higher states in the system will quickly follow. Average or low rainfall following fire will slow the transitions among states, and fires of small extent or low intensity will only lead to transitions to adjacent states.

Specifically my research seeks to test that peaks in rainfall stimulate germination in ephemerals and flowering of perennials and thus ultimately increase seed production. To test the hypothesis that fires initially deplete seed abundance I will establish experimental fire and water regimes to track the fate of seeds in the seed bank.

The research findings should advance our understanding of the role that rainfall and fire play in the ecology of arid habitats, and should provide resource managers with information that facilitates the sustainable management of Australia's native flora and fauna.

Publications

Parratt. N. T., (1996), The Potential of the Non Timber Forest Products of Botswana, Botswana Notes and Records; The Journal of The Botswana Society, 28, 203-218.