@misc{McGrathSadlerFlemingetal., author = {McGrath, Gavan S. and Sadler, R. and Fleming, K. and Tregoning, P. and Hinz, Christoph and Veneklaas, Erik J.}, title = {Tropical cyclones and the ecohydrology of Australia's recent continental-scale drought}, issn = {0094-8276}, doi = {10.1029/2011GL050263}, language = {en} } @misc{GwenziVeneklaasBlebyetal., author = {Gwenzi, Willis and Veneklaas, Erik J. and Bleby, Timothy M. and Yunusa, Isa A.M. and Hinz, Christoph}, title = {Transpiration and plant water relations of evergreen woody vegetation on a recently constructed artificial ecosystem under seasonally dry conditions in Western Australia}, series = {Hydrological Processes}, volume = {26}, journal = {Hydrological Processes}, number = {21}, issn = {1099-1085}, doi = {10.1002/hyp.8330}, pages = {3281 -- 3292}, abstract = {Understanding transpiration and plant physiological responses to environmental conditions is crucial for the design and management of vegetated engineered covers. Engineered covers rely on sustained transpiration to reduce the risk of deep drainage into potentially hazardous wastes, thereby minimizing contamination of water resources. This study quantified temporal trends of plant water potential (ψp), stomatal conductance (gs), and transpiration in a 4-year-old evergreen woody vegetation growing on an artificial sandy substrate at a mine waste disposal facility. Transpiration averaged 0.7 mm day-1 in winter, when rainfall was frequent, but declined to 0.2 mm day-1 in the dry summer, when the plants were quite stressed. In winter, the mean ψp was -0.6 MPa at predawn and -1.5 MPa at midday, which were much higher than the corresponding summer values of -2.0 MPa and -4.8 MPa, respectively. The gs was also higher in winter (72.1-95.0 mmol m-2 s-1) than in summer (<30 mmol m-2 s-1), and negatively correlated with ψp (p < 0.05, r2 = 0.71-0.75), indicating strong stomatal control of transpiration in response to moisture stress. Total annual transpiration (147.2 mm) accounted for only 22\% of the annual rainfall (673 mm), compared with 77\% to 99\% for woody vegetation in Western Australia. The low annual transpiration was attributed to the collective effects of a sparse and young vegetation, low moisture retention of the sandy substrate, and a superficial root system constrained by high subsoil pH. Amending the substrate with fine-textured materials should improve water storage of the substrate and enhance canopy growth and deep rooting, while further reducing the risk of deep drainage during the early stages of vegetation establishment and in the long term. Overall, this study highlights the need to understand substrate properties, vegetation characteristics, and rainfall patterns when designing artificial ecosystems to achieve specific hydrological functions. Copyright © 2011 John Wiley \& Sons, Ltd.}, language = {en} } @misc{GwenziHinzBlebyetal., author = {Gwenzi, Willis and Hinz, Christoph and Bleby, Timothy M. and Veneklaas, Erik J.}, title = {Transpiration and water relations of evergreen shrub species on an artificial landform for mine waste storage versus an adjacent natural site in semi-arid Western Australia}, series = {Ecohydrology}, volume = {7}, journal = {Ecohydrology}, number = {3}, issn = {1936-0592}, doi = {10.1002/eco.1422}, pages = {965 -- 981}, abstract = {In water-limited environments, transpiration may minimize deep drainage on engi-neered covers used for hazardous waste disposal. However, comparative studies investigating plant ecophysiology and water use on engineered covers and natural sites are limited. Water use patterns and plant-water relations of evergreen shrubs were monitored in semi-arid Western Australia to (1) investigate the response of plant-water relations and shrub transpiration to soil moisture changes and (2) quan-tify stand transpiration and its contribution to the water balance. The shrubs showed conservative (<20 cm hr-1) but persistent transpiration. Differential response to rainfall pulses was evident among species; sap velocity for Acacia bivenosa and Acacia inaequilatera increased by 20-103\% (p < 0•05) after rainfall events ex-ceeding 15 mm but declined rapidly to pre-storm levels. On the contrary, sap veloc-ity for Acacia pruinocarpa increased by 61\% after large pulse (83 and 127 mm) as-sociated with cyclonic activity and remained high (10-15 cm hr-1) thereafter. These transpiration patterns suggested contrasting rooting patterns among the spe-cies. Sap velocity was low (<20 mm hr-1) for all species, even when moisture was readily available. Annual shrub transpiration was 65 (engineered cover) and 81 mm (natural shrubland), accounting for 16 and 20\% of annual rainfall (395 mm). Stand characteristics, plant ecophysiology and shrub transpiration were comparable for both sites, demonstrating the importance of using topsoil as a growth medium and seedbank in revegetation. Overall, the study provided insights on ecophysiological behaviour of artificial landforms, and the first empirical evidence suggesting rapid and successful restoration of mined lands can be achieved under semi-arid conditions.}, language = {en} }