Abstract: To understand the variation characteristics of ciliate community and aquatic environment quality of Lhalu wetland in Tibet during summer and autumn, the ciliate species diversity and community structure were investigated by using site sampling, direct observation (in vivo) and fixedstaining methods in July and October of 2011 and 2012. A total of 110 ciliate species were identified, including 15 uncertain species, belonging to 53 genera, 44 families, 13 orders and 3 classes. Hypotrichida and Prostomatida were the dominant groups; Karyorelictida and Synhymeniida were occasional groups; the others were common groups. Coleps hirtu, Cinetochilum margaritaceum, and Strobilidium gyrans were the dominant species in summer. There were no dominant species in autumn. The distribution of ciliate species in the Lhalu wetland showed high heterogeneity temporally and spatially. The average species diversity index was higher in autumn (3.3) than in summer (2.7). The analysis of correlation between the community structure and major water environmental variables suggested that water temperature was the major factor controlling the variations of ciliate community structure in summer. Evaluation of water quality showed that the water quality of the Lhalu wetland was slightly disturbed by human activities.

Key words: Phragmites australis, Tamarix ramosissima, soil enzyme, growth period