Differences and similarities between water sources of Tamarix ramosissima, Nitraria sibirica and Reaumuria soongorica in the southeastern Junggar Basin

Abstract

Aims Water is the most important limiting factor for plant growth in desert ecosystems. Our objective was to investigate the water sources of three co-existing desert plants and illustrate seasonal variation characteristics in southeastern Junggar Desert in China. Methods We investigated three kinds of desert plants (Tamarix ramosissima, Nitraria sibirica and Reaumuria soongorica) in the same habitat and measured hydrogen and oxygen stable isotope ratio (δD and δ18O) values of their xylem water and potential water sources (precipitation, soil moisture and ground water). The IsoSource model was then used to calculate probable contributions of potential water sources to total plant water uptake. Important findings The water sources of the three desert plants had obvious seasonal characteristics. Reaumuria soongorica and N. tangutorum obtained a high proportion of water from shallow soil water (0–100 cm) in spring. However, during the summer and autumn, R. soongorica tended to use deeper soil water, and N. tangutorum tended to use ground water. Tamarix ramosissima obtained 90% of its water from deep soil water and ground water, and there were no seasonal variations. The three kinds of plants had different water sources closely related to their water use strategies. This shows desert shrubs, through self-regulation, could tend to their optimal phenotypes and maximize water uptake.