Water use patterns of dominant species of riparian wetlands in arid areas

Water resource shortage in arid areas is the main cause of ecological problems. Understanding plant water use patterns is essential for understanding soil-plant interactions and assessing the adaptability of plants in ecosystems with limited water resources. Riparian wetlands are functional transition areas connecting aquatic ecosystems and terrestrial ecosystems. Wetland vegetation restoration is of great significance to water conservation and ecological balance. Using isotope tracing method, our study clarified the water use patterns of dominant plants in typical riparian wetlands in arid areas. The results showed that the dominant herbal species of Salsola affinis mainly used 0-60 cm soil water (48.96%). Salsola affinis, which continuously obtains water from shallow soil, may be difficult to survive in extreme drought conditions. If it withered significantly aged in the dry season, it would have a negative ecological impact. The dominant tree species of Salix matsudana Koidz mainly used 20-100 cm soil water (43.99%) and groundwater (23.16%). With increasing water stress, S. matsudana Koidz had a greater degree of ecological plasticity and can use water from deeper soils. However, S. matsudana Koidz can continuously obtained water from deep soil and groundwater, which may weaken the water and soil conservation capacity of the wetland. In addition, the lc-excess value of soil water showed that the soil evaporation intensity of grassland was higher than that of forest land, and the surface evaporation depth reached 60 cm. Our findings will help better understand the impact of vegetation restoration plan (artificial forest land and natural grassland) on the hydrological process of riparian wetland in arid areas, and provide reference for plant species selection and water resources management.