Variations in stream water uptake by Eucalyptus camaldulensis with differing access to stream water

• Published in: Oecologia Vol. 100; no. 3; pp. 293 - 301
• Main Authors: Thorburn, P.J. (Commonwealth Scientific and Industrial Research Organisation, Glen Osmond (Australia). Div. of Water Resources. Centre for Groundwater Studies), Walker, G.R
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01-12-1994; Springer
• Subjects: ABSORCION DE AGUA; ABSORPTION D'EAU; Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; AGUA DULCE; AGUA SALINA; AGUA SUPERFICIAL; AGUAS SUBTERRANEAS; Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Biological and medical sciences; CARBONE; CARBONO; COURS D'EAU; CRECIDA; CRUE; CURSOS DE AGUA; EAU DOUCE; EAU SALINE; EAU SOUTERRAINE; EAU SUPERFICIELLE; ESTRES DE SEQUIA; Eucalyptus camaldulensis; Floods; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Groundwater; Leaves; Plants and fungi; RELACIONES PLANTA AGUA; RELATION PLANTE EAU; River water; Soil samples; Soil water; Soil water content; Streams; STRESS DU A LA SECHERESSE; Surface water; TECHNIQUE DES TRACEURS; TECNICAS DE TRAZADORES; USO DEL AGUA; UTILISATION DE L'EAU; VEGETACION RIPICOLA; VEGETATION RIPICOLE; Water balance and requirements. Evapotranspiration; Water channels; Australia; Oceania; Queensland; Australia, Murray R; Forests; Water management; Isotope labelling; Long term test; Environmental factor; Stem; Dicotyledones; Chlorides; Angiospermae; Humidity; Myrtaceae; Hardwood forest tree; Water absorption; Chemical concentration; Stream; Habitat; Ground water; Plant leaf; Water use efficiency; Eucalyptus camaldulensis; Water potential; Environmental design; Edaphic factor; Flood plain; Water level; Water quality; Spermatophyta; Riparian zone ecology; Phreatophyte; Stable isotope ratio; Water uptake patterns Water use efficiency
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/BF00316957

The stable isotopes (2)H and (18)O were used to determine the water sources of Eucalyptus camaldulensis at three sites with varying exposure to stream water, all underlain by moderately saline groundwater. Water uptake patterns were a function of the long-term availability of surface water. Trees with permanent access to a stream used some stream water at all times. However, water from soils or the water table commonly made up 50% of these trees' water. Trees beside an ephemeral stream had access to the stream 40-50% of the time (depending on the level of the stream). No more than 30% of the water they used was stream water when it was available. However, stream water use did not vary greatly whether the trees had access to the stream for 2 weeks or 10 months prior to sampling. Trees at the third site only had access to surface water during a flood. These trees did, not change their uptake patterns during 2 months inundation compared with dry times, so were not utilising the low-salinity flood water. Pre-dawn leaf water potentials and leaf (13)C measurements showed that the trees with permanent access to the stream experienced lower water stress and had lower water use efficiencies than trees at the least frequently flooded site. The trees beside the ephemeral stream appeared to change their water use efficiency in response to the availability of surface water; it was similar to the perennial-stream trees when stream water was available and higher at other times. Despite causing water stress, uptake of soil water and groundwater would be advantageous to E. camaldulensis in this semi-arid area, as it would provide the trees with a supply of nutrients and a reliable source of water.