Kotaki A.,Shinshu University |
Katoh S.,Museum of Nature and Human Activities |
Kitani K.,Earth Environment and Energy Service Company of Kyoto
Quaternary International | Year: 2011
Analyses of chemical compositions and refractive indices of mafic minerals have been effective correlation tools, especially for crystal-rich tephra layers containing isolated volcanic glass shards. The analyses are applied to the correlation of the Middle Pleistocene tephra layers in the Kinki and Chubu districts, central Japan, with those erupted from Daisen Volcano in the Chugoku Mountains, west of the districts. On the basis of chemical compositions of hornblende phenocrysts and refractive indices of hornblende, orthopyroxene and cummingtonite phenocrysts, four groups of tephra layers in the Kinki and Chubu districts are successfully correlated to bvs2, cpm, gpm and hpm1, or DOP tephra layers of the Lowermost Member of the Daisen Tephra Formation. The correlation reveals that two tephra layers, bvs2 and cpm, with estimated eruption ages of 410. ka and 370-400. ka, respectively, are present in the Kinki district. The hpm1 tephra, about 210. ka, is also widespread and recognized at the eastern foot of Yatsugatake Volcanoes about 400. km east of the source. These tephra layers can contribute to establishing the regional correlation and chronology of the Middle Pleistocene sequences in central Japan, especially for the time from MIS 7 to MIS 11. © 2011 Elsevier Ltd and INQUA.
Takano A.,Museum of Nature and Human Activities |
Okada H.,Osaka City University
Journal of Plant Research | Year: 2011
To determine evolutionary relationships among all Japanese members of the genus Salvia (Lamiaceae), we conducted molecular phylogenetic analyses of two chloroplast DNA (cpDNA) regions (rbcL and the intergenic spacer region of trnL-trnF:trnL-trnF) and one nuclear DNA (nrDNA) region (internal transcribed spacer, ITS). In cpDNA, nrDNA, and cpDNA+nrDNA trees, we found evidence that all Japanese and two Taiwanese Salvia species are included in a clade with other Asian Salvia, and Japanese Salvia species were distributed among three subclades: (1) S. plebeia (subgenus Sclarea), (2) species belonging to subg. Salvia, and (3) species belonging to subg. Allagospadonopsis. At the specific level our findings suggest: a close relationship between S. nipponica and S. glabrescens, no support for monophyly of S. lutescens and its varieties in cpDNA, nrDNA and cpDNA+nrDNA trees, and that S. pygmaea var. simplicior may be more closely related to S. japonica than to other varieties of S. pygmaea. © 2010 The Botanical Society of Japan and Springer.
Kodate S.,Museum of Nature and Human Activities
Nature and Human Activities | Year: 2013
The topography, vegetation and soil properties were investigated in a stand of red pine (Pinus densiflora Sieb. et Zucc.) forest on a ridge-shaped slope in Sanda City, Hyogo Prefecture. The purpose of this study is to clarify the relationship between the degree of damage of the forest from the pine wilt disease and environmental and topographic factors, such as the position on the slope and the maximum capillary-water capacity of the soil. The degree of elongation growth of the red pine tended to be smaller on the upper part of the slope than the lower part. There was also a tendency of more frequent, severer pine root die-back damage on the lower part of the slope than the upper part. The total basal area was higher in plots with severe pine wilt damage than in other plots. The soil in the investigated area was thin in effective depth and poor development. The soil water-repellency was weaker in plots with severe pine wilt damage than in the other plots. Plots with severe damage from the pine wilt disease had a better soil moisture environment than the other plots. Resistance of the red pine to the dryness was weak, and trees that had developed in a good moisture environment appeared prone to root desiccation during periods of extraordinary summer dryness.
Uematsu Y.,Kobe University |
Koga T.,Kobe University |
Mitsuhashi H.,Museum of Nature and Human Activities |
Ushimaru A.,Kobe University
Agriculture, Ecosystems and Environment | Year: 2010
Although traditional agricultural land use maintains biodiversity, recent land-use changes involving abandonment or use intensification have rapidly reduced the biodiversity of agricultural landscapes. Organisms living in agricultural landscapes are likely to respond differently to these changes, with some species declining rapidly and others remaining unchanged. However, few studies have focused on this interspecific difference in susceptibility to land abandonment and intensification in agricultural landscapes. We hypothesize that rarer herb species are more susceptible to both abandonment and intensification than are common herbs due to habitat preferences in the semi-natural grasslands of agricultural landscapes. To test this hypothesis, we examined the distributions of two pairs of congeneric grasslands species on abandoned and consolidated (production-intensified) paddy fields to assess differences in vulnerability to paddy abandonment and consolidation between the rarer and the more common species in an agricultural landscape. We found that higher, steeper fields farther from roads in the upper areas of paddy terraces were more frequently abandoned in our study area. The two rarer species had significantly more overlap with the distribution of fields at risk of abandonment than did the two more common congeneric species. In addition, the two rarer species were significantly less widely distributed in consolidated fields. Thus, both land abandonment and intensification appear to asymmetrically decrease habitats of rarer species. In light of our findings, we also discuss biodiversity conservation in agricultural landscapes with changing land use. © 2009 Elsevier B.V. All rights reserved.
Iwata T.,Yamanashi University |
Urabe J.,Tohoku University |
Mitsuhashi H.,Museum of Nature and Human Activities
Conservation Biology | Year: 2010
Interfaces between terrestrial and stream ecosystems often enhance species diversity and population abundance of ecological communities beyond levels that would be expected separately from both the ecosystems. Nevertheless, no study has examined how stream configuration within a watershed influences the population of terrestrial predators at the drainage-basin scale. We examined the habitat and abundance relationships of forest insectivorous birds in eight drainage basins in a cool temperate forest of Japan during spring and summer. Each basin has different drainage-basin geomorphology, such as the density and frequency of stream channels. In spring, when terrestrial arthropod prey biomass is limited, insectivorous birds aggregated in habitats closer to streams, where emerging aquatic prey was abundant. Nevertheless, birds ceased to aggregate around streams in summer because terrestrial prey became plentiful. Watershed-scale analyses showed that drainage basins with longer stream channels per unit area sustained higher densities of insectivorous birds. Moreover, such effects of streams on birds continued from spring through summer, even though birds dispersed out of riparian areas in the summer. Although our data are from only a single year, our findings imply that physical modifications of stream channels may reduce populations of forest birds; thus, they emphasize the importance of landscape-based management approaches that consider both stream and forest ecosystems for watershed biodiversity conservation. © 2010 Society for Conservation Biology.