Distribution of evergreen broad-leaved forests, inferred from phytolith, in the southernmost area of the Japanese Archipelago between the terminal Pleistocene and early Holocene

Abstract

In this study, we investigated the vegetation history of the southernmost area of Kyushu, southern Japan, by analyzing phytolith assemblages from buried soils, thereby providing insights into the distribution and transition of evergreen broad-leaved forests from the terminal Pleistocene to the early Holocene. On Tanegashima Island, evergreen forests were present during the terminal Marine Isotope Stage (MIS) 3. On southern Kyushu Island, in contrast, mixed forests consisting of coniferous and deciduous broad-leaved trees along with Bambusoideae and Andropogoneae grasslands expanded, and few evergreen trees survived. During the early and middle MIS 2, Sasa grasslands expanded across the inland areas of southern Kyushu, and mixed forests were also present. Evergreen broad-leaved forests were sparse and confined to Tanegashima Island and the lowlands of southern Kyushu. The early Holocene witnessed the establishment of evergreen forests throughout the study region, subsequent to the decline of Bambusoideae grasslands under climate warming. The development of evergreen forests began at approximately 13,000 cal yr BP, with widespread establishment across the study region by approximately 7300 cal yr BP.