Abstract: By using non-flooded Petri dish method, live observation, and protargol dyeing, this paper studied the ciliate species diversity in the plateau swamp wetlands of southern Gansu Province in autumn, with the relationships between the ciliate community’s structural parameters and environmental factors analyzed by grey relational analysis. At six sampling sites, a total of 157 ciliate species were collected, belonging to 53 genera, 34 families, 11 orders, and 3 classes, among which, 1 species was new, 24 species were uncertain, and 4 species were newly recorded in China. Among the species identified, Hypotrichida was the most predominant group, followed by Prostomatida, while Oligorichida and Bursariomorphida were of rare groups. The common groups included Colpodida,  Nassulida, Cyrtophorida, Hymenostomatida, Scuticociliatida, Heterotrichida, and Peritrichida. Due to the habitat peculiarity in the plateau swamp wetlands, the ciliate species diversity and community complexity were high, rare and endemic species had greater proportion, while cosmopolitan species occupied smaller proportion. Grey relational analysis showed that the abundance of ciliate species at the sampling sites had close correlations with the microhabitat environmental factors, among which, organic matter and ammonium nitrogen contents were the major factors affecting the ciliate community stability in the plateau swamp wetlands.

Key words: Pinus koraiensisdominated broadleaved mixed forest, forest gap, pit and mound complex, distribution pattern.