Management-mediated facilitation: Miscanthus sinensis functions as a nurse plant in Satoyama grassland

Abstract

Facilitation can occur when one species changes form to function as a nurse plant. Miscanthus sinensis grasslands are one component of the typical Satoyama landscape. Due to dieback, the shoot density of M. sinensis decreases with increasing patch size, forming “fairy rings” and subsequently facilitating the establishment of co-existing plants by improving soil and light conditions. M. sinensis forms fairy rings also with human management efforts, particularly burning or cutting. In this study, it was hypothesized that M. sinensis fairy rings created by human management function as a nursery for other species in Sengokuhara grasslands maintained by burning or cutting. To test this hypothesis, the plant species richness inside and outside M. sinensis fairy-ring patches was compared after management events. Species richness was higher inside M. sinensis patches than outside the patches. The type of management method also affected plant species richness. Total number of species and the number of woody plant species were significantly lower in the burned areas than in the cut areas, whereas the reverse was observed for the number of spring ephemeral species. These differences may have been caused by micro-environmental differences generated by management methods and by plant life forms. The results indicate that management-induced facilitation may play an important role in conserving plant species diversity in Satoyama grasslands.