Abstract: The karst Tiankeng is an unique negative landform with a huge and enclosed space, which forms a special habitat suitable for bryophyte growth and development. In order to study the relationship between environmental factors and distribution of Hypopterygiaceae, and their vertical distribution characteristics in Monkey-Ear Tiankeng(diameter of 300 m, and depth of 280 m) in Guizhou Province, 12 sampling sites in the Tiankeng were investigated in our fieldwork, and laboratory analysis and Canonical Correspondence Analysis(CCA) were used, and compared with the bryoflora of other sampling sites like karst rocky desertificated zone and Tiankeng marginal zone. The results showed that:(1)There were three genera and nine species of Hypopterygiaceae in the Tiankeng, accounting for 47.37% of the total species of this family in China, and accounting for 69.23% of the total species of this family in Guizhou, of which the Hypopterygiumflavo-limbatum C.Muell was more common species in six spots with a frequency of occurrence 50%; (2)Air humidity, light, canopy density, and human disturbance were the main environmental factors affecting the distribution of Hypopterygiaceae in the Monkey-Ear Tiankeng. The descending order in the influence of environmental factors was soil water content, soil pH, gradient, and air temperature; (3)The descending order in species richness of Hypopterygiaceae was karst Tiankeng,Tiankeng marginal zone,and desertification area; (4)In the vertical distribution pattern, the Hypopterygiaceae showed that the bottom of the Tiankengwas the center of biodiversity, and the distribution from the crater to the bottom was gradually increasing. It is a natural refuge for karst rocky desertification.

Key words: Karst Tiankeng, Hypopterygiaceae, Environmental factor, Canonical Correspondence Analysis(CCA)