Degradation and recovery of an alpine plant community: experimental removal of an encroaching dwarf bamboo

The dwarf bamboo Sasa kurilensis has responded to recent climate change by expanding its distribution into alpine snow meadows in Japan. Tall, dense clonal patches of bamboo suppress alpine plant growth, alter ecosystem functioning, and reduce diversity. We aim to assess the ecological impacts of bamboo expansion and the effectiveness of bamboo control for restoring alpine vegetation and species diversity. We quantified the extent of bamboo expansion, its effects on an alpine ecosystem, and the recovery of species diversity by bamboo removal over 6 years in Daisetsuzan National Park, northern Japan. We established paired, experimental plots assigned to either removal or control treatments following an encroaching gradient from interior to terminal locations in a large bamboo patch. We monitored bamboo development and aboveground production, and its impact on soil moisture and species diversity to assess the recovery process of snow meadow species after its removal. In control plots, bamboo density consistently increased and accumulated biomass from year to year. In the removal treatment, bamboo culm density, height and biomass decreased through time at all locations. Furthermore, soil moisture increased in the removal plots and remained consistently higher than controls throughout the growing season. Dwarf bamboo strongly suppressed alpine plants and reduced species diversity. However, alpine snow meadow species rapidly recovered and diversity increased through time in the removal treatment. This study presents an effective management strategy for restoring alpine plant diversity impacted by bamboo expansion under global climate change.