Abstract:The main protection objects of the Yaoluoping Nature Reserve are typical representative forest vegetation and the national key protected, rare and endangered animal and plant resources in the Dabie Mountain area. It is also an important water conservation forest reserve in the Dabie Mountains. The total area of the reserve is 123 km2, which is divided into three functional areas. The core area is 21.2 km2 (including Shifosi-Dachuanling core area, Diaojujing core area, Qilingou core area and Duozhijian core area), the buffer area is 28.4 km2, and the experimental area is 73.4 km2. This paper took the herbaceous plants under the deciduous broad-leaved forest 11.56 km2 permanent sample plot in the Yaoluoping National Nature Reserve as the research objects, and then investigated the plant diversity, spatial distribution pattern, interspecific association, and correlation of dominant species in the herb layer. The main results are as follows:1. The herbaceous plants investigated in the sample plot belong to 52 families, 134 genera and 195 species. The floristic geographical compositions of herbaceous plants in the Yaoluoping sample plot are complex, covering many distribution types. Among them, there are more temperate elements, accounting for 60.44% of the total genera. The results showed that the temperate characteristics of deciduous broad-leaved forest communities were obvious. Tropical plants accounted for 18.66% of the total genera. The herbaceous plants in the sample plot had an obvious affinity to the temperate growth environment.2. Analysis of important values of 195 herbaceous plants in plot showed that the important values of Carex breviculmis, Carex brachyathera, Carex siderosticta, Elymus kamoji, Viola acuminata, Galium hoffmeisteri, Cardamine engleriana, Cardamine macrophylla, Carex sp., and Galium bungei accounted for 58.57% of the total, and they were the dominant species in the plot. Among them, the Carex breviculmis had a significant advantage in the plot.3. Species diversity not only reflects the species richness of community composition and the degree of uniform distribution among species, it also reflects the relationship between different physical and geographical conditions and the community, as well as the stability and dynamics of the community. It is an important feature of the combination of community organization. Through analysis of Simpson index, Shannon-Wiener index, and Pielou evenness index of herbaceous plants in the sample plot, it is found that the dominant species of herbaceous plants in this area are obvious, the herbaceous plant diversity is rich, and the overall distribution is relatively uniform. The area with high species diversity is concentrated in the central and southern corner of the river, and the species diversity on shady slope of the south is higher than that on sunny slope of the north.4. Diffusion coefficient (C), average congestion degree (m*), negative binomial parameter (K), cluster index (I), agglomeration index (PI), cassie index (CA), green index (GI) and other methods were used to analyze the spatial distribution patterns of the dominant species. The species correlation was measured according to the 2×2 joint list and coefficient (AC) and χ2 statistics. The results demonstrated that the herbaceous plants were mostly aggregated, and the positive correlation of species was higher than negative correlation, but the correlation intensity was low. It indicated that the community remained in the unstable succession stage.5. In the Spearman rank correlation test of the dominant populations in the large sample plot, among the 45 species pairs of the first 10 herbaceous dominant species, 27 species pairs showed positive correlation, accounting for 60.00% of the total species logarithm. Among them, the logarithm with extremely significantly positive correlation was 17, accounting for 37.78% of the total species logarithm, and the species logarithm with a significantly positive correlation was 1, accounting for 2.22% of the total species logarithm. The species logarithm with negative correlation among species pairs was 18, of which the species logarithm with extremely significant negative correlation was 9, accounting for 20.00% of the total species logarithm. The species logarithm with significantly negative correlation was 2, accounting for 4.44% of the total species logarithm. The total species logarithm which was not significant was 16 pairs, accounting for 35.56% of the total species logarithm. The results showed that the correlation among the dominant species was not strong, and the interspecific state was loose as a whole, which was consistent with the results of the dominant population χ2-test. The association test among herbaceous species in large sample plots of mountain deciduous broad-leaved forest showed that the scope of Pearson correlation coefficient test was for the data of continuous and linear relationship between two variables, normal distribution or near-normal unimodal distribution. However, the Spearman rank correlation coefficient test did not require the overall distribution shape of the two variables and the size of the sample size. The investigation and monitoring of herb under the deciduous broad-leaved forest provided an importantly theoretical basis for the effective protection and rational utilization of precious herb resources under the forest.