A new distribution record of Gleditsia L. in Guizhou and its community characteristics

Through field surveys and specimen identification, a new distribution record for a Gleditsia species in Guizhou was established, namely Gleditsia australis. To further understand the characteristics of the community where G. australis is found, and to make full use of and protect the resources of the Gleditsia genus, three 20 m × 20 m plots were set up in Liping County and Tianzhu County for community investigation. The species composition, life forms, community structure, and plant diversity of the communities were analyzed. The results show: (1) G. australis represents a new distribution record for Gleditsia species in Guizhou, occurring in Liping County, Tianzhu County, and Libo County. (2) The three communities contain 49 families, 83 genera, and 103 species of vascular plants. Community I has 21 families, 27 genera, and 29 species; Community II has 26 families, 36 genera, and 39 species; Community III has 34 families, 48 genera, and 56 species. There were obvious differences among families, genera and species (3) The community is dominated by small-sized, high-bud plants and dwarf high-bud plants, exhibiting typical characteristics of the subtropical Central Asian region. The community has a distinct stratification, which can be divided vertically into the tree layer, shrub layer, and herbaceous layer. (4) The average diameter at breast height (DBH) of Community III is 9.1 cm, and its diameter class structure follows an "inverted J-shape" with a lack of larger diameter individuals but good regeneration. Communities I and II have similar diameter class ranges, and their successional stages are more advanced.