Background Mine tailings are one of the most serious and longest lasting products of environmental damage generated by mining activities. As an extremely degraded habitat, the tailings dam in the Zhongtiaoshan copper mine area is extremely difficult to restore the vegetation, and ecological restoration is urgently needed. The characteristics of naturally colonized herbaceous plant communities in the Shibahe tailings dam of the Zhongtiaoshan copper mining area were studied to reveal the relationship between herbaceous community diversity and environmental factors, and to screen out the dominant herbaceous species suitable for ecological restoration of tailing dam in copper mine area, so as to provide scientific basis for ecological restoration of tailing dams in copper mine area.

Methods In September 2020, a total of 54 sampling plots were surveyed in 1 m×1 m samples of the naturally colonized herbaceous plant community at the tailings dam in the Zhongtiaoshan copper mining area according to the gradient change in elevation. The characteristics of naturally colonized herbaceous plant community in the tailings dam of Zhongjianshan copper mine area, was studied by using the methods of TWINSPAN classification, DCA ordination, M. Godron stability, and species diversity index. SPSS 20.0, Excel 2010 and Origin 2021 software were used for data analysis.

Results 1) A total of 43 species belonging to 16 families and 38 genera were recorded in 54 sampling plots in the naturally colonized herbaceous plant community of the study area.2) 54 sampling plots of naturally colonized herbaceous plant communities in study area were divided into ten associations(Ⅰ-Ⅻ) by TWINSPAN classification. Association Ⅹ located at the top of tailings dam had the shortest revegetation period, while Associations I and II located at the bottom of tailings dam had the longest revegetation period.3) The community stabilities of the ten Associations were ranked as follows: Ⅳ>Ⅷ>Ⅶ>Ⅴ>Ⅰ>Ⅲ>Ⅵ>X>IX>Ⅱ, which indicated that all the ten Associations were in a relatively unstable state.4) The first DCA axis of 54 quadrats represented the changes of the revegetation period and the altitude of the tailings dam, and the second DCA axis represented the change of plant ecotypes.5) The revegetation period were the major limiting factors affecting the composition of the naturally colonized herbaceous plant communities in the tailings dam of the Zhongtiaoshan copper mining area.6) One-way ANOVA showed that the Patrick richness index and Shannon-Wiener heterogeneity index of ten Associations were significantly different(P < 0.05).

Conclusions The dominanrt plant species of Pennisetum alopecuroides and Bothriochloa ischaemum could be used in the ecological restoration of the tailings dams of Zhongjianshan copper mine area in the future.