Abstract
Pollen analytical studies were made on materials collected from two sites in a mire developed on Yururi Island to clarify the vegetation history of Nemuro Peninsula in easternmost Hokkaido since the Late Glacial. A landscape consisting of grassland and poor birch forests existed around this area ca. 12,000 years ago. Thereafter, a larch forest began to invade and formed a boreal forest on this island. Picea glehnii forests began to increase in this area ca. 10,000 years ago. The larch forest was extinct ca. 8000 years ago, but Picea glehnii forests continuously occupied this area until ca. 4500 years ago. After this period woody vegetation never developed on Yururi Island. Though coniferous forests deteriorated due to climatic warming, cool temperate oak forests have not developed fully in Nemuro Peninsula because of the cool and wet climate of the summer season. Boreal birch forests gradually developed in this area, and boreal coniferous forests began to increase in the western part of Nemuro Peninsula during the last 2500 years. However, coniferous forests has not developed fully in the eastern part yet.
