Jianxin Ma

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

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.

Changes of Value of Ecosystem Services and its Driving Forces in the Lower Reaches of the Tarim River

In this paper, we used TM image data in the lower reaches of the Tarim River as well as ecosystem service value assessment methods, and assessed the change of regional land use/ cover and analyzed its ecosystem service value, and discussed the driving forces of the change factors. The results show that : the study area is mainly grassland and desert grasslands accounted for more than 43% , the desert about 32% , less than 6% of the forest area , waters and wetlands area , less than 1% of the total area, which mean that the area is mainly the oasis agriculture , desertification serious water shortages. Since 2000, the , the ecological restoration project significantly effective under the emergency water conveyance on the lower reaches of the Tarim River, woodland restoration and water area increased , the desert area has decreased. GDP continued to increase from 2000 to 2005, the value of ecosystem services greatly reduce. In a shorter time scale, agricultural development and human activity are the dominant factors of the transfer of the value of ecosystem structure adjustment and service functions in the study area.