Ayako Shimono - Academia.edu (original) (raw)
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Papers by Ayako Shimono
Journal of Plant Ecology, Feb 10, 2010
To describe the biodiversity patterns of plants along an altitudinal gradient on the Qinghai-Tibe... more To describe the biodiversity patterns of plants along an altitudinal gradient on the Qinghai-Tibetan Plateau and to clarify the bias in plant specimen records at high altitude. We conducted a large-scale investigation of vegetation at a wide range of altitudes, focusing on a high-altitudinal range (3 200-5 200 m) at different locations on the Qinghai-Tibetan Plateau. We then compared the altitudinal distribution of plant species obtained from our field investigation with that in plant specimen records from published sources and an online database. Our data provide evidence that altitude plays a large role in regulating species composition on the Qinghai-Tibetan Plateau. We could not, however, detect a clear relationship between altitude and spe-cies richness, although a weak monotonically increasing trend of richness was detected with increasing altitude. According to specimen records, most species have been sampled at a wide range of altitudes, and the average range of 145 species is >2 000 m. Despite this wide range, more than half of the species we observed were at higher altitudes than the specimen records indicate. High-altitude areas have probably been so poorly sampled that only a small fraction of the resident species has been recorded. This study clearly shows the regional bias of specimen records in the Qinghai-Tibetan Plateau. Keywords: altitudinal gradient d alpine plant d species composition d species richness d specimen bias
Journal of Plant Ecology, 2009
Aims Our objectives were (i) to elucidate the phylogeography of chloroplast DNA (cpDNA) in Potent... more Aims Our objectives were (i) to elucidate the phylogeography of chloroplast DNA (cpDNA) in Potentilla fruticosa in relation to Quaternary climate change and postglacial colonization, (ii) to infer historical population range expansion using mismatch distribution analyses and (iii) to locate the refugia of this alpine species on the Qinghai-Tibetan plateau during glacial-interglacial periods. Methods Potentilla fruticosa is a widespread species distributed on the Qinghai-Tibetan Plateau. We sampled leaves of P. fruticosa from 10 locations along a route of ;1 300 km from the northeastern plateau (Haibei, Qinghai) to the southern plateau (Dangxiong, Tibet). We examined the cpDNA of 15 haplotypes for 87 individuals from the 10 populations based on the sequence data from ;1 000 base pairs of the trnS-trnG and rpl20-rps12. Phylogenetic relationship of haplotypes was analyzed using the Phylip software package and the program TCS. The diversity of populations indices was obtained using the program ARLEQUIN. Important Findings With the limited samples, we found that (i) higher nucleotide diversity often occurs in high-altitude populations, (ii) the ancestral haplotypes distribute in the populations with higher nucleotide diversity than recent haplotypes, (iii) the expansion time of population in the high altitudes was estimated to be approximately at 52-25 ka BP (1000 years Before Present, where ''Present'' is AD 1950) and that in the low altitudes to be ;5.1-2.5 ka BP and (iv) the source location of P. fruticosa is at the high altitudes, which might provide refugia for the species during the interglacial warm periods. The species expanded from the high-elevated locations on the Tanggula Mountains during the Holocene. Keywords: alpine plants d climatic changes d cpDNA d Qinghai d Tibet
Heredity, 2009
The Qinghai-Tibetan Plateau is one of the most extensive habitats for alpine plants in the world.... more The Qinghai-Tibetan Plateau is one of the most extensive habitats for alpine plants in the world. Therefore, the patterns of genetic variation in populations on the Plateau can reveal the detailed demographic history of alpine plants. We analysed the geographical structure of chloroplast matK sequence variation in Potentilla fruticosa L. (Rosaceae), a shrub currently found across the entire Plateau. We obtained sequence data from 508 individuals from 23 populations at sites ranging from the high-altitude interior to the relatively low-altitude northeastern Plateau. In the interior region, genetic diversity was high and included ancestral haplotypes. In contrast, northeastern populations were characterized by relatively low genetic diversity and recently derived haplotypes. The estimated expansion time in the interior population was 17 times that in the northeastern population. These data suggest that P. fruticosa expanded its range on the Plateau during periods of climatic cooling and contracted to the interior region during warmer periods. Thus, the interior region acted as a refugium and greatly contributed to the diversification of P. fruticosa.
Journal of Geography (Chigaku Zasshi), 2013
Journal of Plant Ecology, Feb 10, 2010
To describe the biodiversity patterns of plants along an altitudinal gradient on the Qinghai-Tibe... more To describe the biodiversity patterns of plants along an altitudinal gradient on the Qinghai-Tibetan Plateau and to clarify the bias in plant specimen records at high altitude. We conducted a large-scale investigation of vegetation at a wide range of altitudes, focusing on a high-altitudinal range (3 200-5 200 m) at different locations on the Qinghai-Tibetan Plateau. We then compared the altitudinal distribution of plant species obtained from our field investigation with that in plant specimen records from published sources and an online database. Our data provide evidence that altitude plays a large role in regulating species composition on the Qinghai-Tibetan Plateau. We could not, however, detect a clear relationship between altitude and spe-cies richness, although a weak monotonically increasing trend of richness was detected with increasing altitude. According to specimen records, most species have been sampled at a wide range of altitudes, and the average range of 145 species is >2 000 m. Despite this wide range, more than half of the species we observed were at higher altitudes than the specimen records indicate. High-altitude areas have probably been so poorly sampled that only a small fraction of the resident species has been recorded. This study clearly shows the regional bias of specimen records in the Qinghai-Tibetan Plateau. Keywords: altitudinal gradient d alpine plant d species composition d species richness d specimen bias
Journal of Plant Ecology, 2009
Aims Our objectives were (i) to elucidate the phylogeography of chloroplast DNA (cpDNA) in Potent... more Aims Our objectives were (i) to elucidate the phylogeography of chloroplast DNA (cpDNA) in Potentilla fruticosa in relation to Quaternary climate change and postglacial colonization, (ii) to infer historical population range expansion using mismatch distribution analyses and (iii) to locate the refugia of this alpine species on the Qinghai-Tibetan plateau during glacial-interglacial periods. Methods Potentilla fruticosa is a widespread species distributed on the Qinghai-Tibetan Plateau. We sampled leaves of P. fruticosa from 10 locations along a route of ;1 300 km from the northeastern plateau (Haibei, Qinghai) to the southern plateau (Dangxiong, Tibet). We examined the cpDNA of 15 haplotypes for 87 individuals from the 10 populations based on the sequence data from ;1 000 base pairs of the trnS-trnG and rpl20-rps12. Phylogenetic relationship of haplotypes was analyzed using the Phylip software package and the program TCS. The diversity of populations indices was obtained using the program ARLEQUIN. Important Findings With the limited samples, we found that (i) higher nucleotide diversity often occurs in high-altitude populations, (ii) the ancestral haplotypes distribute in the populations with higher nucleotide diversity than recent haplotypes, (iii) the expansion time of population in the high altitudes was estimated to be approximately at 52-25 ka BP (1000 years Before Present, where ''Present'' is AD 1950) and that in the low altitudes to be ;5.1-2.5 ka BP and (iv) the source location of P. fruticosa is at the high altitudes, which might provide refugia for the species during the interglacial warm periods. The species expanded from the high-elevated locations on the Tanggula Mountains during the Holocene. Keywords: alpine plants d climatic changes d cpDNA d Qinghai d Tibet
Heredity, 2009
The Qinghai-Tibetan Plateau is one of the most extensive habitats for alpine plants in the world.... more The Qinghai-Tibetan Plateau is one of the most extensive habitats for alpine plants in the world. Therefore, the patterns of genetic variation in populations on the Plateau can reveal the detailed demographic history of alpine plants. We analysed the geographical structure of chloroplast matK sequence variation in Potentilla fruticosa L. (Rosaceae), a shrub currently found across the entire Plateau. We obtained sequence data from 508 individuals from 23 populations at sites ranging from the high-altitude interior to the relatively low-altitude northeastern Plateau. In the interior region, genetic diversity was high and included ancestral haplotypes. In contrast, northeastern populations were characterized by relatively low genetic diversity and recently derived haplotypes. The estimated expansion time in the interior population was 17 times that in the northeastern population. These data suggest that P. fruticosa expanded its range on the Plateau during periods of climatic cooling and contracted to the interior region during warmer periods. Thus, the interior region acted as a refugium and greatly contributed to the diversification of P. fruticosa.
Journal of Geography (Chigaku Zasshi), 2013