Vegetation patterns on a landslide after five years of natural restoration in the Loess Plateau mining area in China

Landslides represent the most intense type of geological disaster in the gully region of the Loess Plateau and have caused great damage to surface vegetation. Natural restoration is considered as an effective method for revegetation, however, vegetation patterns on landslides after natural restoration and its related factors remain poorly understood. The present study investigated vegetation patterns on a landslide after 5 years of natural restoration, which located in Hezhai coal mining area, Shanxi Province, China, to understand the natural restoration of vegetation after landslides. The species composition on the bottom, middle and top of the landslide, as well as the species importance value, plant diversity and similarity were ascertained and compared with the that on undisturbed site. Furthermore, the soil seed bank in another landslide which just experienced 0.5-year natural restoration was also investigated, and a seed bank germination experiment was performed based on the collected seed samples from the landslide to test their vitalities. Results showed that 20 species of vegetation were found on all three parts of the landslide, which all belonged to herbaceous plants and shrubs. Eleusine indica was dominant in both the bottom and middle of the landslide, while the top was dominated by Potentilla sischanensis. From the bottom to the top of landslide, the Margalef Index was 3.26, 3.91, and 2.17 respectively; the Shannon–Wiener Index was 2.56, 2.60, and 2.13 respectively; the Pielou Index was 0.55, 0.56, and 0.46, respectively. Species similarity revealed a close relationship between species compositions on restored landslide and undisturbed area. A total of 13 species of seeds were found in the soil seed bank, which were also similar to the aboveground plants on disturbed site and the landslide after 5-year natural restoration, and the seed was also proved vital in the seed bank experiment. These results indicated that vegetation on landslides could recovery naturally, and natural restoration was more effective on the bottom and middle of the landslide, which revealed that changes in topography could affect revegetation. The seed bank in the soil was considered as a main factor affecting natural restoration. This research provides useful insight into the natural restoration of vegetation after landslides, and provides a reference for the selection of ecological restoration strategies.