Physiological condition and water source use of Sonoran Desert riparian trees at the Bill Williams River, Arizona, USA

J. L. Horton, S. C. Hart, Thomas E Kolb

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

We investigated the environmental water sources used in mid-summer by three Sonoran Desert phreatophytic riparian tree species, Salix gooddingii, Populus fremontii, and the exotic Tamarix spp., at sites that differed in water table depth. Salix gooddingii was most sensitive to water table decline, as evidenced by lower predawn water potentials. Although P. fremontii was less sensitive to water table decline than S. gooddingii, its leaf gas exchange was the most responsive to atmospheric water stress imposed by high leaf-to-air vapor pressure deficit. Tamarix spp. was least sensitive to water table decline and showed no reduction of predawn water potential over the measured range of depth to groundwater. Comparison between D/H of xylem and sampled environmental water sources suggest that S. gooddingii and P. fremontii used groundwater at most sites with no change in water source as depth to groundwater varied. In contrast, xylem D/H of Tamarix spp. was depleted in deuterium compared to groundwater at most sites, suggesting on of water from an unsampled source, or discrimination against deuterium during water uptake. This study highlights the difficulty in sampling all water sources in largescale studies of riparian ecosystems with complex subsurface hydrogeology.

Original languageEnglish (US)
Pages (from-to)69-82
Number of pages14
JournalIsotopes in Environmental and Health Studies
Volume39
Issue number1
DOIs
StatePublished - Mar 2003

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Keywords

  • Groundwater
  • Hydrogen 2
  • Leaf gas exchange
  • Natural variations
  • Riparian ecosystem
  • Sonoran Desert
  • Trees
  • Water stress

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Environmental Science(all)
  • Environmental Chemistry

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