ObjectiveIn this study, the Guizhou Chishui Alsophila spinulata National Nature Reserve was taken as the research site, and the characteristics of different plant communities were analyzed and compared to provide a scientific basis for the effective protection of rare and endangered plants as well as the typical forest ecosystem of the subtropical evergreen broadleaved forest.

Method73 quadrats were established in the study area. Through sample survey, the community characteristics were analyzed from the aspects of species composition, floristic characteristics, life form and community structure.

Result(1) There were 91 families, 180 genera and 251 species of tracheophyte in the reserve. Among them, there were 16 families, 21 genera and 25 species of pteridophytes.The top three species of community importance value were Musa basjoo, Phyllostachys pubescens and Alsophila spinulosa. (2) The flora composition of community spermatophyte was mainly tropical and contained a certain proportion of temperate components. The life form was dominated by microphanerophytes, and the therophytes were the least. (3) Community vertical structure can be divided into four layers: tree layer, sub tree layer, shrub layer and herb layer, the high-layer edificator of main Phyllostachys pubescens, Cunninghamia lanceolata, Betula luminifera and Lindera pulcherrima var. hemsleyana etc, and middle-layer edificator mainly included the Musa basjoo, Mallotus philippensis, Brassaiopsis glomerulata and Casearia balansae, etc, low-layer edificator included Eurya japonica, Actinodaphne cupularis and Maesa montana, etc. The average height of the Alsophila spinulosa was 3.58 m. it had a dominant position in the shrub layer and a stable age structure. (4) DBH of the tree layer plants was mainly 2-8 cm, shrub layer was mainly less than 3 cm, species with an average DBH greater than 9 cm were mainly found Musa basjoo, Cunninghamia lanceolata, Betula luminifera and A. spinulosa, etc. Species with an average DBH less than 5 cm were mainly found Eurya japonica, Actinodaphne cupularis and Maesa montana, etc., the DBH of Alsophila spinulosa was stable, and the average DBH was 12.2 cm. (5) The 73 investigation quadrats had been divided into 14 groups, which were divided into 10 formation, respectively for form. P. pubescens, M. basjoo, A. spinulosa-M. basjoo-B. glomerulata, Pinus massoniana, P. zhennan, C. lanceolata, B. luminifera, Liquidambar formosana-Gordonia acuminata, P. zhennan-B. controversum-C. axillaris var. pubinervis and form. B. controversum. The plant diversity and evenness increased with elevation. Among them, the form. A. spinulosa-M. basjoo-B. glomerulata was the most unevenly distributed.

ConclusionThe diversity and structure of plants in different communities in the reserve area were obviously different, altitude was the main environmental factor affecting the spatial distribution of community.The higher elevation area was mostly the montane mixed evergreen and deciduous broadleaved forest and typical broadleaved forest, community stability was higher. The low-elevation areas of gully valley are mostly south Asian tropical evergreen broadleaved bushes, and the dominant species represented by plantain Musa basjoo and Phyllostachys pubescens are prominent. The community species composition and structure are single, which is the main growth environment of cymbidium, and its habitat range is relatively narrow.