Abstract: Understanding herbaceous plant resources in temperate forests is of great significance for biodiversity conservation. We investigated herb diversity in 450 quadrats (1 m×1 m) in a 20 hm² plot of warm temperate deciduous broad-leaved forest in Donglingshan from 2015 to 2018, compared the species composition and quantitative characteristics of herbaceous layer across four years. We classified the floristic types based on families and genera, and analyzed the dynamics of species diversity and structure. There were 62, 55, 57, and 56 herbaceous species within the four years, respectively. The dominant species were Deyeuxia pyramidalis, Saussurea mongolica and Carex lanceolata, which remained unchanged within four years. The temperate floristic characteristics were obvious. The Patrick richness index, Shannon diversity index, Simpson dominance index and Pielou evenness index of herbaceous species were significantly different among the four years. The vertical stratification of herbaceous plants was obvious, with large proportion of plants in the range of 10-20 cm in height. The number of species and individuals were unevenly distributed horizontally in the plot. The proportion of species in each frequency level was unstable. The majority of herbaceous species were the low-abundance species, and the high-abundance species were few.

Key words: understory herbaceous layer, species composition, floristic characteristics, species diversity