The invasion of Pinus pumila and Sasa kurilensis following the drying of moor on Mt. Hiragatake, the mountainous area of Gunma and Niigata prefectures, Central Japan

Abstract

This paper documents the vegetation distribution of the moor on the summit of Mt. Hiragatake and its circumference, located on the boundary between Gunma and Niigata Prefectures, to clarify the invasion of nonnative vegetation after the moor became arid. It is clear that Pinus pumila and Sasa kurilensis, nonnative moor vegetation, invaded the moor from the circumference. They were distributed over the boundary region of the moor, and P. pumila invaded the moor first, forming shrub vegetation. The shrub blocked the northwesterly wind in winter, forming an environment with a temperature not too low and high desiccation, allowing S. kurilensis to invade. Such an environment protects S. kurilensis, it became vigorously. Finally, S. kurilensis replaced P. pumila. The invasion of other nonnative moor vegetation will simultaneously progress further following the invasion of S. kurilensis.