Study on vegetation change of Taitemar Lake during ecological water transfer

Abstract

The present study investigating the variation in plant diversity in Taitemar Lake before and after ecological water transfer is critical for the restoration of the ecological environment of the lower Tarim River. A comprehensive study of the vegetation in Taitemar Lake from 2000 to 2017 was conducted, to determine differences between the overflow and the non-overflow areas, which were monitored along belt transects. There are some conclusions: (1) the ecological benefits of Taitemar Lake gradually emerged with increased water transfer: in the overflow area, the number of species per unit area, vegetation cover, and vegetation density were 6.8 species per 100 m², 30%, and 1350 per 100 m², respectively, while the three indices above in the non-overflow area were 1.7 species per 100 m², 7.0%, and 27.0 per 100 m², respectively. (2) In recent decades, the major changes in Taitemar Lake were as follows: in the early stage of water transport (2000–2006), the surface vegetation was dominated by newly germinated annual herbs (important value (IV) 0.50), followed by perennial herbs (IV 0.20), and finally shrubs (IV 0.10). After a few years, in 2008, the annual herbs almost disappeared in the overflow are and were replaced by shrubs and perennial herbs. Shrubs were the newly germinating seedlings of native species, and perennial herbs were dominated by Phragmites australis. From 2012 to 2016, under the abundant water conditions, the dominant species composition tended to be simple and the local vegetation developed in the direction of a saline meadow. (3) From 2011 to 2017, P. australis became the dominant species on the shoreline with the Simpson and Shannon indices remaining at low levels.