干旱区生态环境知识资源中心

Based on the CBERS images and meteorological data of the upper and middle reaches of Tarim River, this paper analyzed the distribution characteristics of natural vegetation dominated by Populus euphratica Oliv. and calculated the ecological water requirement of the desert riparian forest by using the methods of quota-area and phreatic evaporation. The results were shown as follows. (1) The total area of natural vegetation in the upper and middle reaches of Tarim River is 18,550.26 km(2), the area of sparse woodlot is 3283.40 km(2), forest land is 2476.60 km(2), high cover grassland is 6476.44 km(2), and low cover grassland is 6313.82 km(2). (2) From the distribution of natural vegetation, the vegetation area in the Section 1, Section 2, Section 3, and Section 4 is 25.5%, 34.5%, 23.8%, and 16.2% of the total, respectively. The pattern of regional natural vegetation has three characteristics: the area of the natural vegetation is decreasing in the vertical direction of river, and the vegetation distribution exist difference along the river. Additionally, the north bank has larger vegetation distribution area than the south bank. (3) For the natural vegetation protection, if the protection rate is 95% or 90%, the distribution range of the natural vegetation on the north bank would be 27.45 +/- 10.04 km and 23.87 +/- 10.17 km respectively while the distribution range on the south bank would be 26.13 +/- 3.77 km and 20.64 +/- 7.32 km, respectively. (4) Based on above vegetation distribution range, the minimum ecological water requirements under the same two protection rates are 21.610 +/- 1.832x10(8) m(3) and 19.758 +/- 1.537x10(8) m(3), respectively. These studies would provide a theoretic basis for the determination of water resource rational allocation and environmental conservation in Tarim River.