Diversity patterns of mosses and its determinants in Maolan (Guizhou Province, China) in view of species and function

Guizhou Maolan National Nature Reserve has rare karst forest ecosystems, which are unique in the world at the same latitude. To elucidate moss diversity pattern and its environmental factors in the reserve in view of species and function, species composition and distribution of mosses in 342 sites were investigated in five representative landscapes (stone-hillside forest, funnel forest, karst valley, ancient plum forest and villages). A total of 1 668 moss specimens were collected, from which 319 species belonging to 106 genera and 36 families were identified. Among the five landscape types, species richness was highest in karst valley (Qinglong Pond) and Stone-hillside Forest, and the species diversity was highest in Stone-hillside Forest, followed by karst valley. There was no significant difference in functional diversity among these five landscapes. Among different substrates, species diversity of saxicolous mosses and epiphytic mosses was higher than that of soil-based mosses. Saxicolous mosses had the highest functional divergence and richness index, and epiphytic mosses had comparatively high functional evenness. Species diversity and functional diversity of ground mosses increased significantly with the increase of tree canopy coverage, but decreased or decreased significantly with the increase of herb coverage, soil thickness and substrate moisture. With the increase of elevation, species diversity and functional diversity of saxicolous mosses increased to an extent, while the epiphytic mosses somewhat decreased. Significantly positive correlations existed between species richness and functional richness, between species diversity and functional divergence, and between species evenness and functional evenness for the mosses in the Reserve, all at a significance of p<0.001. In karst areas with different desertification degrees, bryophyte diversity increased with the improvement of desertification environment.