关键词: 塔里木河下游, 植物群落, 空间分布, 影响因素

Abstract: In order to explore the spatial distribution of plant communities and their influencing factors in the lower reaches of Tarim River, 36 sample plots and important values of plant species surveyed in the field were used to classify the number of plant communities by the two-way indicator species analysis method (TWINSPAN), and the distributions of plant communities and influencing factors were analyzed by detrended correspondence analysis (DCA), canonical correspondence analysis (CCA) and detrended canonical correspondence analysis (DCCA). The results showed that: ①among all the plots investigated, T. ramosissima had the highest frequency, accounting for 8611% of the total plots. P. euphratica accounted for 41.67% of the total plots. P. aviculare, H. caspica, C. physodes, S. pellucida and K. scoparia had the lowest frequency, accounting for 2.78% of the total plots. ②TWINSPAN classification classified all samples into 9 plant clusters, and the performance of their spatial distribution showed that P. euphratica, T. ramosissima and P. australis were mainly dominant species within 50 m reaches from the river. P. euphratica, A. sparsifolia, H. halodendron, T. ramosissima and P. australis were the dominant species within 150—500 m reaches from the river. P. euphratica and T. ramosissima were the dominant species within 500—1 050 m reaches from the river. ③ The cumulative contribution rates of the first two principal component factors on environmental factors reached more than 50%. The contribution rate of each factor and the significance analysis showed that the total salt content and the depth of groundwater were main influence factors on the spatial distribution of plant communities in the lower reaches of Tarim River, which had great significance for studying the quantitative characteristics of plant communities, vegetation protection and ecological restoration in the lower reaches of Tarim River.

Key words: lower reaches of Tarim River, plant community, spatial distribution, influencing factors