Dr John Passioura 'Perennial plants living with limited water: lifestyles, landscapes and some effects of disturbance'

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Thursday, 11 October 2012 - 12:30pm

Plant communities interact strongly with surface hydrology, and in so doing shape landscapes.  John will cover a few examples, including kangaroo grass, mallee, jarrah, and mulga. Disturbance of these vegetation types has had some remarkable hydrologic consequences, especially the conversion of kangaroo grass to ‘improved’ pastures, which immediately and unexpectedly resulted in farm dams drying up.  Likewise, the properties of the subsoils under jarrah and mallee have been massively shaped by the roots of the vegetation which have created permanent biopores in the soil. These biopores are repeatedly colonised by roots, and can convey fresh water deeply into the subsoil for later use during the demandingly dry summers. Above ground, much of the water during a rainfall is guided by the leaves and stems of the canopy towards the trunks, where the infiltration rate is especially high, and where the dominant biopores often start.


John Passioura is widely experienced in the environmental physiology of plants, especially in relation to the productive use of water by crops growing in semi-arid environments. He is currently an Honorary Research Fellow with CSIRO Plant Industry, where he is continuing to work on improving the performance of dryland crops and the landscapes in which they grow.