Factors affecting occurrence of erosion and establishment of indigenous species from surrounding vegetation at revegetated slopes in early stage

Abstract

To determine the factors contributing to both the control of erosion and the establishment of indigenous species dispersed from vegetation surrounding slopes in the early stages, we investigated the influence of location and construction methods on the occurrence of erosion and indigenous species cover at 293 sites located on slopes, which had been constructed within the past five years in Yamanashi prefecture, using a generalized linear mixed model. Erosion of the surface layer was observed in 37% of the study sites. The mean plant cover at all sites was relatively high, although there were few slopes where indigenous species were observed. Sites sprayed with a soil/seed cultivation base and located in valleys had a greater coverage by indigenous species and were considered to have established indigenous species faster than the other sites studied. In contrast, the use of a thick cultivated base spraying method and revegetation mats helped to control erosion, while both methods suppressed the establishment of indigenous species. The results suggest that either the control of erosion or the establishment of indigenous species on the slopes should be prioritized when selecting which revegetation method to use. To create favorable conditions for both slope stability and the establishment of an indigenous species community on cut slopes, it is important to consider the selection of revegetation methods, the composition of plant species introduced, and the control of wildlife damage.