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Accueil du site → Master → Etats Unis → 2020 → Water Sourcing Strategies of Highly Resilient Vegetation in Desert Soils : Stable Isotope Analysis of a Northern Chihuahuan Desert Ecosystem

University of Texas at El Paso (2020)

Water Sourcing Strategies of Highly Resilient Vegetation in Desert Soils : Stable Isotope Analysis of a Northern Chihuahuan Desert Ecosystem

Thompson Hayden Eleanor

Titre : Water Sourcing Strategies of Highly Resilient Vegetation in Desert Soils : Stable Isotope Analysis of a Northern Chihuahuan Desert Ecosystem

Auteur : Thompson Hayden Eleanor

Université de soutenance : University of Texas at El Paso

Grade : Master of Science (MS) 2020

Résumé partiel
Plant water use strategies and water transport dynamics are important for understanding ecosystem productivity and soil-vegetation-atmosphere interactions within an environment (Li et al., 2007). Recent research using stable isotope analysis in wet and humid climates has found that vegetation uses tightly particle-bound water stored in the soil that does not participate in translatory flow (Brooks et al., 2010 ; Goldsmith et al., 2011 ; McDonnell 2014). In arid and semi-arid deserts of the United States, highly resilient vegetation, such as the Honey Mesquite (Prosopis glandulosa) and the Creosote shrub (Larrea tridentata), exhibit some degree of activity year-round despite limited water availability during the dry season. In an effort to determine the water sourcing strategies of these drought-tolerant species, as well as decern the existence and use of tightly bound soil water in arid and semi-arid environments, we collected and analyzed vegetation stems, soil, and precipitation samples from two sites over a 15-month period in the Jornada Experimental Range (JER) of the Northern Chihuahuan Desert. Using stable isotopes of hydrogen (δ2H) and oxygen (δ18O) we compared the isotopic composition of the mesquite and creosote xylem waters, to that of precipitation and soil water within the two study sites. One site was located in a low-lying channelized area (referred to as the Channel Area) and the other in a slightly higher, flatter area (referred to as the Flat Area). Our results indicate that the location of the vegetation and their associated soil in the landscape has an effect on the isotopic composition of the water they use.

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Page publiée le 26 mai 2021