Vegetation and soil succession determine the water-use strategy ofCaragana korshinskiiin a chronosequence of revegetated areas in Ningxia, Northwest China

AbstractPlant and soil properties and stable isotope data from soil and xylem samples of Caragana korshinskii from four different-aged revegetated sites (1976, 1987, 1996, and 2005) were studied in a desertified steppe ecosystem of Northwest China. Results showed that the revegetation of C. korshinskii had a positive effect on the local habitat restoration. The δ18O values of soil water at the four study sites varied between different months and exhibited a monotonic decline from the soil surface to deep soil layers. The variation of soil water δ18O values in the older revegetated sites was lower than that in the younger revegetated sites. C. korshinskii mainly tapped water from secondary (60–120 cm) and relatively stable (120–250 cm) soil water in the older revegetated site, and they had relatively slight monthly fluctuations. However, in the younger revegetated site, the contribution of active (0–60 cm) soil water increased, and they exhibited a clear shift in the water-use pattern. In the initial stage of vegetation establishment, soil water content played a major role in the plant water-use strategy, but in the middle and later stages of revegetation, plant biological characteristics and soil physical properties were the main impact factors.