Experimental study on water transport observations of desert riparian forests in the lower reaches of the Tarim River in China

Abstract

Studying the water use processes of desert riparian vegetation in arid regions and analyzing the response and adaptation strategies of plants to drought stress are of great significance for developing ecological restoration measures. Based on field monitoring and test analyses of physiological ecological indicators of dominant species (Populus euphratica and Tamarix chinensis) in the desert riparian forest in the lower reaches of the Tarim River, the water relations of P. euphratica and T. chinensis under drought stress are discussed and some water use strategies put forward. The results show that (1) concerning plant water uptake, desert riparian forests depend mainly on groundwater to survive under long-term water stress. (2) Concerning plant water distribution, the survival of P. euphratica and nearby shallow root plants is mainly due to the hydraulic lift and water redistribution of P. euphratica under drought stress. (3) Concerning plant water transport, P. euphratica sustains the survival of competitive and advantageous branches by improving their ability to acquire water while restraining the growth of inferior branches. (4) Concerning plant transpiration, the sap flow curves of daily variations of P. euphratica and T. chinensis were wide-peak sin and narrower-peak respectively. T. chinensis has better environmental adaptability.

Relationships between Plant Communities and Environmental Factors in an Extremely Arid Area: A Case Study in China

“…This shows that the species richness of this region is poor and the ecosystem is unstable. These results confirm the findings reported by Xi et al [17] and Chen et al [18] who also showed that the desert ecosystem in arid and semi-arid areas was more fragile when water and environmental problems are particularly prominent. …”

Tree rings: A key ecological indicator for reconstruction of groundwater depth in the lower Tarim River, Northwest China

“…P. euphratica , a strongly dominant species of the desert riparian forest in the lower Tarim River of northwestern China, is a drought‐tolerant species, and can survive in extremely arid areas and areas with <6–8 m groundwater tables (Chen et al, ; Vishnu et al, ). Due to drought, scarce precipitation, and deep groundwater table in the lower Tarim River, P. euphratica became a deep‐rooted plant that obtained a significant portion of the water that it needed from the phreatic zone, and it could absorb soil water at 375–700 cm and groundwater (Chen et al, ). It has also been reported that the longest roots of P. euphratica could even reach 10 m (http://bbs.tianya.cn/post-333-177925-1.shtm, Li, ).…”

Variation of the floodplain forest ecosystem service value in the lower reaches of Tarim River, China

“…Since the 1970s, the water volume of the riverbed showed a marked decrease after the construction of the Daxihaizi Reservoir, which exacerbated water shortages by drying up the 321‐km riverbed in the lower reaches of the Tarim River (Chen et al, ; Guo et al, ). The groundwater table dropped sharply to 8–12 m due to a lack of surface water refilling for nearly 30 years.…”

“…This resulted in the large‐scale degradation of natural vegetation along with serious environmental degradation problems such as soil wind erosion. Ultimately, these changes and their resulting downstream effects yielded serious environmental damage (Chen et al, ; Wills et al, ).…”

“…In the study area, the mean annual precipitation is less than 60 mm, and the run‐off is 280 × 10 8 m 3 /year (Guo et al, ). The primary water source for the basin is seasonal snow and glacier melt from the higher surrounding mountains, which supply the Tarim River through their various tributaries (Chen et al, ).…”