Alashan Desert Ecohydrology Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China,
Environ Monit Assess. 2014 Sep;186(9):5469-77. doi: 10.1007/s10661-014-3796-4. Epub 2014 May 11.
Desert riparian forests are the main body of natural oases in the lower reaches of inland rivers; its growth and distribution are closely related to water use sources. However, how does the desert riparian forest obtains a stable water source and which water sources it uses to effectively avoid or overcome water stress to survive? This paper describes an analysis of the water sources, using the stable oxygen isotope technique and the linear mixed model of the isotopic values and of desert riparian Populus euphratica forests growing at sites with different groundwater depths and conditions. The results showed that the main water source of Populus euphratica changes from water in a single soil layer or groundwater to deep subsoil water and groundwater as the depth of groundwater increases. This appears to be an adaptive selection to arid and water-deficient conditions and is a primary reason for the long-term survival of P. euphratica in the desert riparian forest of an extremely arid region. Water contributions from the various soil layers and from groundwater differed and the desert riparian P. euphratica forests in different habitats had dissimilar water use strategies.
荒漠河岸林是内陆河流下游天然绿洲的主体，其生长和分布与水源利用密切相关。然而，荒漠河岸林如何获得稳定的水源，以及利用哪些水源来有效避免或克服水分胁迫以生存？本研究采用稳定氧同位素技术，结合同位素值的线性混合模型，对不同地下水埋深和条件下生长的荒漠河岸林胡杨的水源进行了分析。结果表明，胡杨的主要水源由单一土层水或地下水转变为随地下水埋深增加而逐渐向深层土壤水和地下水转变。这似乎是对干旱缺水条件的一种适应性选择，也是胡杨在极端干旱区荒漠河岸林长期生存的主要原因。不同土层和地下水对胡杨的水分贡献不同，不同生境的荒漠河岸林胡杨具有不同的水分利用策略。
