Niche Characteristics of Herbaceous Plants under Pinus tabuliformis Plantation Forest in Feldspathic Sandstone Area

[Objectives] To explore the niche characteristics of herbaceous plants under Pinus tabuliformis plantation forest in the feldspathic sandstone area, and to provide basic data for maintaining biodiversity and community stability in the local P. tabuliformis plantation forest. [Methods] The types, quantity, average plant height, and coverage of various herbaceous plants were recorded by field survey in a well-growing P. tabulaeformis forest area. Based on the survey data, Shannon and Levins niche breadth index, Levins niche overlap index and ecological response were used to analyze the niche characteristics of herbaceous plants under P. tabulaeformis plantation forest. [Results] (i) There were 35 species of herbaceous plants in the P. tabulaeformis plantation forest in the feldspathic sandstone area. Among them, Stipa bungeiensis had the largest niche breadth indexes with better performance. Because of its strong adaptability, its community was in an obviously advantageous position. (ii) The overall niche width and niche overlap index were generally not high, and understory herb species showed differentiation. (iii) Among the understory herbaceous species, 37.15% of the species were developed species, and 62.86% of the species were declining species. Among the 14 dominant species, 11 were developmental species. The species with largest the resource occupancy were S. bungeiensis (0.188 5), Heteropappus altaicus (0.053 1), and Cleistogenes squarrosa (0.037 9). [Conclusions] Competition among under herbaceous plants in P. tabulaeformis plantation forest in the feldspathic sandstone area was weak, and the community species had poor utilization of resources and environment. Most of the dominant herbaceous species were in the developing stage, indicating that the P. tabulaeformis plantation community tends to be relatively stable at the current stage.