Patterns of Water Use by Great Basin Plant Species Under Summer Watering

• Published in: Arid land research and management 2014-10, Vol.28 (4), p.428-446
• Main Authors: Mata-González, Ricardo, Evans, Tracie L., Martin, David W., McLendon, Terry, Noller, Jay S., Wan, Changgui, Sosebee, Ronald E.
• Format: Article
• Language: English
• Subjects: Arid zones; Artemisia tridentata; Atriplex confertifolia; desert shrubs; Distichlis spicata; Ericameria; evapotranspiration; Freshwater; Grasses; groundwater; Irrigation; Juncus arcticus; phreatophytes; root systems; Salix exigua; Salsola; Sporobolus airoides; Summer; Tragus; Vegetation; Water
• ISSN: 1532-4982; 1532-4990
• DOI: 10.1080/15324982.2014.886088

We analyzed temporal and spatial patterns of water use by a functionally-diverse group of Great Basin plant species and determined their water use rates at the whole-plant and individual-leaf scales under variable summer watering. Species studied were the desert grasses Distichlis spicata and Sporobolus airoides, the desert shrubs Artemisia tridentata, Ericameria nauseosa, and Atriplex confertifolia; the wetland/riparian plants Juncus arcticus, Leymus triticoides, and Salix exigua; and the annual exotic Salsola tragus. Plant species were individually grown in 5.8 m 2 plots in a common garden in eastern California. Three irrigation treatments in the form of monthly pulses were applied during the summer: low (1.3 cm), medium (2.6 cm), and high (3.9 cm), in addition to a nonirrigated control. Whole-plant water uptake characteristics were determined by soil water depletion at different soil depths, while leaf transpiration was determined by gas exchange. Whole-plant water extraction and leaf transpiration varied similarly among species. Desert shrubs had low water extraction (35 to 395 g m −2  day −1 ) and were not affected by irrigation. The desert grasses and riparian/wetland species had higher water extraction, increasing with irrigation levels. L. triticoides and J. arcticus had the highest water extraction overall (>2,000 g m −2  day −1 ). Desert shrubs relied 10 times more on deeper water sources than herbaceous species. The average T/ET was 31%, but varied by species. Summer available water in environments such as the Great Basin favors desert grasses and riparian/wetland species, but not desert shrubs. The observed species differences provide alternatives for water and vegetation management.