Abstract
Recently, it has been reported that the vegetation on the moor of Mt. Hiragatake is changing. This moor is located on the boundary between Gunma and Niigata prefectures, central Japan. To clarify this change in vegetation, we compared aerophotographs of Hiragatake moor obtained at different times. The distortion in these aerophotographs was removed using correction software (orthonized). The moor area was calculated using GIS software based on the orthonized aerophotographs. The results reveal that the moor area was reduced by 10% over the period of 33 years from 1971 to 2004. Further, we investigated the part of the moor where the vegetation had changed markedly and found that patches of Pinus pumila had colonized the interior regions of the moor. Furthermore, we found Sasa kurilensis growing thickly on the moor edges. We examined the ecological characteristics and invasive forms of S. kurilensis and P. pumila. Our results clarify that P. pumila was the pioneering species invading the moor and it played the main ecological role in changing the vegetation of the moor. Moreover, S. kurilensis was the main plant with area changes in the moor. The change in vegetation is believe to have occurred due to the decrease in snowfall which is related to the origin and maintenance of the moor.
