Water sources of typical plants during the rainy season in desertification areas of the agro-pastoral ecotone in northern China

Abstract

The agro-pastoral ecotone in northern China is an important ecological security barrier for central and eastern China. Ecological restoration in this zone is very important due to its fragile ecosystem structure, frequent ecological and environmental problems, and severe land desertification. The plant-soil water relationship is essential to ecological and hydrological processes in land desertification areas. Studying the water conversion process between plants and soil is of great importance for understanding the water absorption patterns of plants and determining the preferred plant species for ecological restoration. Taking northern Kangbao County, Zhangjiakou City, Hebei Province as the study area, this study analyzed the water uptake layer, ecological niche width, and water competition of typical plants based on the hydrogen and oxygen isotopic characteristics of rainfall, groundwater, soil water, and xylem water during the rainy season, were analyzed. The results showed that Caragana korshinskii mainly absorbed soil water at a depth of 80-100 cm, with a maximum water uptake rate of 87.7%, while Brassica campestris mainly absorbed soil water at a depth of 0-20 cm, with a maximum water uptake rate of 82.3%. The water absorption layer of Stipa baicalensis was related to the soil moisture content, and the depth of water absorption of Neopallasia pectinata was more balanced. The ecological niche of each plant species is relatively wide, but there is intense water competition among some plants. This study provides a scientific basis for identifying plant water sources and ecological restoration in desertification areas of the agro-pastoral ecotone in northern China.

Keywords

• agro-pastoral ecotone
• desertification area
• typical plant
• stable hydrogen and oxygen isotopes
• water source
• niche breadth
• proportional similarity