Data from: Increased snowfall weakens complementarity of summer water use by different plant functional groups

Winter snowfall is an important water source for plants during summer in
semiarid regions. Snow, rain, soil water, and plant water were sampled for
hydrogen and oxygen stable isotopes analyses under control and increased
snowfall conditions in the temperate steppe of Inner Mongolia, China. Our
study showed that the snowfall contribution to plant water uptake
continued throughout the growing season and was detectable even in the
late growing season. Snowfall versus rainfall accounted for 30% and 70%,
respectively, of the water source for plants, on the basis of hydrogen
stable isotope signature (δD) analysis, and accounted for 12% and 88%,
respectively, on the basis of oxygen stable isotope signature (δ18O)
analysis. Water use partitioning between topsoil and subsoil was found
among species with different rooting depths. Increased snowfall weakened
complementarity of plant water use during summer. Our study provides
insights into the relationships between precipitation regimes and species
interactions in semiarid regions.

冬季降雪是半干旱地区夏季植物重要的水分来源。本研究在中国内蒙古温带草原样地中设置对照与增雪处理，分别采集降雪、降雨、土壤水与植物水样品，开展氢氧稳定同位素分析。本研究发现，降雪对植物水分吸收的贡献贯穿整个生长季，甚至在生长季末期仍可被检测到。基于氢稳定同位素（δD）特征分析结果，降雪与降雨分别占植物水分来源的30%与70%；而基于氧稳定同位素（δ¹⁸O）特征分析结果，二者占比则分别为12%与88%。不同根系深度的植物物种间存在表层土壤与亚表层土壤的水分利用分异现象。夏季增雪处理削弱了植物水分利用的互补性。本研究为揭示半干旱地区降水格局与物种互作间的关联提供了新的认知。