Vegetation history after the late period of the Last Glacial Age based on phytolith records in Nangodani Valley basin, southern part of the Aso caldera, Japan

Abstract

Vegetation history after the late period of the Last Glacial Age has been reconstructed using phytolith records obtained from three tephra sections in the Nangodani Valley basin, southern part of the Aso caldera, southwest Japan. The topography of the Nangodani Valley basin is divided into three types: somma (caldera rim and wall), caldera floor (central valley) and post-caldera central cone slope. The vegetation transitions after the late period of the Last Glacial Age in the basin vary between these topographic types. The differences can be explained based on human activities in the valley basin. Grassland dominated by Sasa and Pleioblastus dwarf bamboos (before 8 ka) and Miscanthus and other Andropogoneae pampas grasses (after 8 ka) occurred in the central valley and on the postcaldera central cone slope, which were strongly affected by human activities including a long period of burning. In contrast, forest with an understory of Bambusoideae plants was preserved on the caldera rim and wall, which was inaccessible because of its steep topography, during the Holocene.

Genetic diversity and demography of Bufo japonicus and B. torrenticola (Amphibia: Anura: Bufonidae) influenced by the Quaternary climate

“…Volcanic activity in the central Kyushu ( Mahony et al, 2011 ) may have prevented clade B2 from inhabiting this region, which was also suggested by the increase in the effective population size after LGM. Vegetation in central Kyushu was also affected by volcanic activity around LGM, which contributed to the cool climate ( Miyabuchi, Sugiyama & Nagaoka, 2012 ; Miyabuchi & Sugiyama, 2020 ). Hynobius stejnegeri endemic to Kyushu diverged into northern and southern populations in central Kyushu (as Hynobius yatsui , Sakamoto et al, 2009 ), indicating that volcanic activity has long restricted amphibian migration.…”

Crossing new frontiers: extending tephrochronology as a global geoscientific research tool

“…(23) (15) South East Asia (Bouvet de la Maisonneuve and Bergal-Kuvikas (2020) (16) Aira caldera, Japan (Nishizawa and Suzuki, 2020) (17) Aso caldera, Japan (Miyabuchi and Sugiyama, 2020) (18) Lake Suigetsu, Japan (Maruyama et al, 2020) (19) Tohoku area, Japan (Suzuki et al, 2020) (20) Towada volcano, Japan (Ishimura and Hiramine, 2020) (21) Kamchatka Peninsula, Russia (Zelenin et al, 2020) (22) Meiji Rise, NW Pacific Ocean (Derkachev et al, 2020) (23) Auckland Volcanic Field, New Zealand (Peti et al, 2020) show that the eruptives can be distinguished using their glass geochemistry, thereby providing a key reference dataset to aid the identification of distal deposits.…”

“…The occurrence of this tephra layer in deep‐sea sediments could provide an age for the eruption and, overall, a key regional chronological marker for the Middle Pleistocene could be defined. In the second paper, Miyabuchi and Sugiyama (2020) reconstruct vegetation history within the Aso caldera using phytoliths. Three sections, from after the late period of the Last Glacial Age, were studied with dating control provided by tephra layers, with notably the K‐Ah present at all sites.…”

Phytoliths as an indicator of change in vegetation related to the huge volcanic eruption at 7.3 ka in the southernmost part of Kyushu, southern Japan

“…For instance, phytolith assemblages in paleosols represent the past vegetation type in situ , which enables us to assess the vegetation change at each site (e.g. Fredlund and Tieszen, 1997; Blinnikov et al, 2001; Miyabuchi and Sugiyama, 2020). Therefore, phytolith studies have been conducted in volcanic regions to assess the influence of eruptions on vegetation and its transition (e.g.…”