Background Mineral mining has formed a large number of rocky high steep slopes that can lead to increased soil erosion and other geologic disasters, so there is an urgent need for ecological restoration of these high steep slopes. The scientific configuration of slope protection plants and the evaluation of their restoration effect is an important part of the ecological restoration research and engineering practice of high and steep slopes, while the significant differences in the natural climate of North China will bring difficulties in the selection of plant species and configuration modes. Therefore, in order to explore the optimal configuration of plants for the ecological restoration of high and steep rocky slopes in North China, we took a typical high and steep rocky slope of Guye district of Tangshan as a research object, and carried out in-situ tests and evaluation of the restoration effect of different plant configurations.

Methods Firstly, 30 species of plants suitable for growing in North China were selected, and three different plant community configurations were designed, and in-situ tests were carried out on the experimental slope by using net spraying. Then, samples were taken during 2 peak plant growth periods (June and September), and biomass statistics and comparative analysis were conducted. Finally, a comprehensive evaluation model of vegetation restoration effect with 10 indicators and 5 levels was established using fuzzy comprehensive evaluation method to evaluate the restoration effect of the 3 plant allocation schemes.

Results 1) The importance values of Cosmos bipinnatus, Medicago sativa and Setaria viridis were higher in all three trial areas: 55.0%, 38.7% and 54.2% for C. bipinnatus, 13.9%, 12.3% and 10.4% for M.sativa, and 10.1%, 11.7% and 13.5% for S. viridis. 2) The community configuration of the trial area dominated by shrubs paired with a small number of arbors, and herbaceous plants were used as the pioneer plants. The experimental area of the community configuration had the highest average height of vegetation cover and trees and shrubs, the largest Shannon-Wiener diversity index and Pielou evenness index, and the smallest Simpson dominance index in the two monitoring sessions in June and September, and the evaluation composite scores were 2.441 and 3.958, respectively, which were the highest among the three configuration modes.

Conclusions In the management of high and steep slopes in North China, the plant allocation mode should be based on shrubs as the main population with a small number of arbors, and herbaceous plants as the pioneer plants to quickly build a stable ecological community system; the fuzzy comprehensive evaluation model based on 10 indicators and 5 levels of vegetation restoration effect can also be applied to the evaluation of ecological restoration effect of slopes in other regions of North China.