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Hokkaido University Collection of Scholarly and Academic Papers (135.711 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

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Mostrando recursos 1 - 20 de 124

  1. Effects of time and environmental conditions on the quality of DNA extracted from fecal samples for genotyping of wild deer in a warm temperate broad-leaved forest

    Agetsuma-Yanagihara, Yoshimi; Inoue, Eiji; Agetsuma, Naoki
    Extraction of DNA from non-invasive samples (feces) has been used increasingly in genetic research on wildlife. For effective and reliable genetic analyses, knowledge about which samples should be selected in the field is essential. For this reason, we examined the process of DNA degradation in feces of deer. We collected fresh fecal pellets from three wild deer living in a warm temperate forest. We then assessed the effects of time (3, 5, and 10 days) under three environmental conditions (on the forest floor, on exposed ground, and inside the laboratory) on the rates of correct genotyping (CG), amplification failure (NA),...

  2. Spatial pattern of soil nitrogen availability and its relationship to stand structure in a coniferous-broadleaved mixed forest with a dense dwarf bamboo understory in northern Japan

    Inoue, Takahiro; Fukuzawa, Karibu; Watanabe, Tsunehiro; Yoshida, Toshiya; Shibata, Hideaki
    Natural disturbances create spatial patterns of the ecosystem processes and functions in natural forests. However, how dynamics and the spatial structure of forests relate to soil nitrogen dynamics is not well understood. We examined the spatial relationship between the distributions of canopy and understory species, and soil nitrogen dynamics in a natural coniferous-broadleaved mixed forest with a dense understory of Sasa dwarf bamboo in northern Japan. The O horizon was thick where coniferous litter predominated, and it was thin where broadleaved litter predominated. The soil water content was low in areas with a thick O horizon and a high abundance...

  3. Structural Complexity and Ecosystem Functions in a Natural Mixed Forest under a Single-Tree Selection Silviculture

    Yoshida, Toshiya; Naito, Sayoko; Nagumo, Misato; Hyodo, Natsumi; Inoue, Taiki; Umegane, Hiromitsu; Yamazaki, Haruka; Miya, Hisashi; Nakamura, Futoshi
    The objective of forest management has become broader, and it is essential to harmonize timber production with conservation of the forest ecosystem. Selection cutting is recognized as a major alternative of clear-cutting, because it can maintain the complexity and heterogeneity of a natural forest; however, its long-term evaluations are limited. This study compared various attributes of stand structures, which are indicators of biodiversity and ecosystem carbon stock between managed and unmanaged blocks (12.6 ha area in total) in a natural mixed forest in Hokkaido, the northernmost island of Japan. We found that 30 years' implementation of single-tree selection did not...

  4. Structural Complexity and Ecosystem Functions in a Natural Mixed Forest under a Single-Tree Selection Silviculture

    Yoshida, Toshiya; Naito, Sayoko; Nagumo, Misato; Hyodo, Natsumi; Inoue, Taiki; Umegane, Hiromitsu; Yamazaki, Haruka; Miya, Hisashi; Nakamura, Futoshi
    The objective of forest management has become broader, and it is essential to harmonize timber production with conservation of the forest ecosystem. Selection cutting is recognized as a major alternative of clear-cutting, because it can maintain the complexity and heterogeneity of a natural forest; however, its long-term evaluations are limited. This study compared various attributes of stand structures, which are indicators of biodiversity and ecosystem carbon stock between managed and unmanaged blocks (12.6 ha area in total) in a natural mixed forest in Hokkaido, the northernmost island of Japan. We found that 30 years' implementation of single-tree selection did not...

  5. Airborne basidiospores as an inoculum source of Typhula variabilis and the effect of hilling on the incidence of Typhula winter rot of carrots

    Ikeda, Sachiko; Hoshino, Tamotsu; Matsumoto, Naoyuki; Kondo, Norio
    Typhula winter rot on overwintering carrots caused by Typhula variabilis is a newly confirmed disease, and no practical control measure is yet available. To develop a control method, here we researched the infection period of T. variabilis and the time that winter rot appeared on carrots. Using spore traps, we found that basidiospore rain occurred from September to November before snowfall in Memuro, Hokkaido. In addition, carrot leaves collected in autumn had already been infected by T. variabilis. These epidemiological investigations revealed that the pathogen releases basidiospores to infect carrot leaves before snow cover, resulting in root decay under snow....

  6. Airborne basidiospores as an inoculum source of Typhula variabilis and the effect of hilling on the incidence of Typhula winter rot of carrots

    Ikeda, Sachiko; Hoshino, Tamotsu; Matsumoto, Naoyuki; Kondo, Norio
    Typhula winter rot on overwintering carrots caused by Typhula variabilis is a newly confirmed disease, and no practical control measure is yet available. To develop a control method, here we researched the infection period of T. variabilis and the time that winter rot appeared on carrots. Using spore traps, we found that basidiospore rain occurred from September to November before snowfall in Memuro, Hokkaido. In addition, carrot leaves collected in autumn had already been infected by T. variabilis. These epidemiological investigations revealed that the pathogen releases basidiospores to infect carrot leaves before snow cover, resulting in root decay under snow....

  7. Marine protected area restricts demographic connectivity: Dissimilarity in a marine environment can function as a biological barrier

    Sato, Masaaki; Honda, Kentaro; Uy, Wilfredo H.; Baslot, Darwin I.; Genovia, Tom G.; Nakamura, Yohei; Bernardo, Lawrence Patrick C.; Kurokochi, Hiroyuki; Pantallano, Allyn Duvin S.; Lian, Chunlan; Nadaoka, Kazuo; Nakaoka, Masahiro
    The establishment of marine protected areas (MPAs) can often lead to environmental differences between MPAs and fishing zones. To determine the effects on marine dispersal of environmental dissimilarity between an MPA and fishing zone, we examined the abundance and recruitment patterns of two anemonefishes (Amphiprion frenatus and A.perideraion) that inhabit sea anemones in different management zones (i.e., an MPA and two fishing zones) by performing a field survey and a genetic parentage analysis. We found lower levels of abundance per anemone in the MPA compared to the fishing zones for both species (n=1,525 anemones, p=.032). The parentage analysis also showed...

  8. Genetic differences among varieties of Saccharina japonica in northern Japan as determined by AFLP and SSR analyses

    Yotsukura, Norishige; Maeda, Takashi; Abe, Tsuyoshi; Nakaoka, Masahiro; Kawai, Tadashi
    The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect...

  9. Genetic differences among varieties of Saccharina japonica in northern Japan as determined by AFLP and SSR analyses

    Yotsukura, Norishige; Maeda, Takashi; Abe, Tsuyoshi; Nakaoka, Masahiro; Kawai, Tadashi
    The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect...

  10. Genetic differences among varieties of Saccharina japonica in northern Japan as determined by AFLP and SSR analyses

    Yotsukura, Norishige; Maeda, Takashi; Abe, Tsuyoshi; Nakaoka, Masahiro; Kawai, Tadashi
    The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect...

  11. Assessment of genetic relationships among cultivated and wild Rubus accessions using AFLP markers

    Miyashita, Tomoya; Kunitake, Hisato; Yotsukura, Norishige; Hoshino, Yoichiro
    The genus Rubus comprises more than 740 species divided into 12 subgenera and contains the raspberries, blackberries, arctic fruits, and flowering raspberries, all of which have been utilized in breeding programs. The objective of this study was to evaluate the phylogenetic relationships among wild and cultivated Rubus species mainly collected in Japan. To evaluate genetic resources in Rubus, 81 accessions were analyzed with three amplified fragment length polymorphism (AFLP) primer pairs and data were analyzed with the neighbor-joining and unweighted pair group methods with arithmetic mean. Two of the generated phylogenetic trees grouped subgenera Anoplobatus, Eubatus, Idaeobatus, and Malachobatus into...

  12. Assessment of genetic relationships among cultivated and wild Rubus accessions using AFLP markers

    Miyashita, Tomoya; Kunitake, Hisato; Yotsukura, Norishige; Hoshino, Yoichiro
    The genus Rubus comprises more than 740 species divided into 12 subgenera and contains the raspberries, blackberries, arctic fruits, and flowering raspberries, all of which have been utilized in breeding programs. The objective of this study was to evaluate the phylogenetic relationships among wild and cultivated Rubus species mainly collected in Japan. To evaluate genetic resources in Rubus, 81 accessions were analyzed with three amplified fragment length polymorphism (AFLP) primer pairs and data were analyzed with the neighbor-joining and unweighted pair group methods with arithmetic mean. Two of the generated phylogenetic trees grouped subgenera Anoplobatus, Eubatus, Idaeobatus, and Malachobatus into...

  13. Karyological evidence of hybridogenesis in Greenlings (Teleostei: Hexagrammidae)

    Suzuki, Shota; Arai, Katsutoshi; Munehara, Hiroyuki
    Two types of natural hybrids were discovered in populations of three Hexagrammos species (Teleostei: Hexagrammidae) distributed off the southern coast of Hokkaido in the North Pacific Ocean. Both hybrids reproduce by hybridogenesis, in which the maternal haploid genome is transmitted to offspring without recombination and the paternal haploid genome is eliminated during gametogenesis. While natural hybrids are unisexual and reproduce hemiclonally by backcrossing with the paternal species (BC-P), artificial F-1-hybrids between the pure species produce recombinant gametes. Thus, despite having the same genome composition, the natural hybrids and the F-1-hybrids are not genetically identical. Here, to clarify the differences between...

  14. Root exudation of low-molecular-mass-organic acids by six tree species alters the dynamics of calcium and magnesium in soil

    Ohta, Tamihisa; Hiura, Tsutom
    Soils in plantations of Cryptomeria japonica in Japan have similar to threefold more exchangeable Ca compared with soils in other types of forest vegetation even in a Ca-poor environment. To explain mechanisms underlying this phenomenon, we determined the effect of root exudation rate of low-molecular-mass organic acids (LMMOAs) on exchangeable cations in soil. We conducted a pot experiment using C. japonica and five dominant tree species in Japan, and measured the root exudation rates of LMMOAs and exchangeable nutrient concentrations in the soils. To estimate whether the root exudation rate of LMMOAs is elevated in response to Ca deficiency, we...

  15. New Multicentury Evidence for Dispersal Limitation during Primary Succession

    Kobayashi, Makoto; Wilson, Scott D.
    Primary succession is limited by both ecosystem development and plant dispersal, but the extent to which dispersal constrains succession over the long-term is unknown. We compared primary succession along two co-occurring arctic chronosequences with contrasting spatial scales: sorted circles that span a few meters and may have few dispersal constraints and glacial forelands that span several kilometers and may have greater dispersal constraints. Dispersal constraints slowed primary succession by centuries: plots were dominated by cryptogams after 20 years on circles but after 270 years on forelands; plots supported deciduous plants after 100 years on circles but after >400 years on...

  16. Flagellar waveforms of gametes in the brown alga Ectocarpus siliculosus

    Kinoshita, Nana; Shiba, Kogiku; Inaba, Kazuo; Fu, Gang; Nagasato, Chikako; Motomura, Taizo
    Brown algae are members of the Stramenopiles and their gametes generally have two heterogeneous flagella: a long anterior flagellum (AF) with mastigonemes and a short posterior flagellum (PF). In this study, swimming paths and flagellar waveforms in free-swimming and thigmotactic-swimming male and female gametes and in male gametes during chemotaxis, were quantitatively analysed in the model brown alga Ectocarpus siliculosus. This analysis was performed using a high-speed video camera. It was revealed that the AF plays a role in changing the locomotion of male and female gametes from free-swimming to thigmotactic-swimming and also in changing the swimming path of male...

  17. Impact of anthropogenic disturbance on the density and activity pattern of deer evaluated with respect to spatial scale-dependency

    Agetsuma, Naoki; Koda, Ryosuke; Tsujino, Riyou; Agetsuma-Yanagihara, Yoshimi
    This study examined the influence of anthropogenic disturbance (agriculture, forestry, hunting and feral domestic dogs) on the population density and daily activity pattern of deer. We quantified the effects of land use (broad-leaved forest, mixed coniferous/broad-leaved forest, natural grassland, subalpine vegetation, forestry area, and agricultural land), along with hunting pressure, and densities of feral domestic dogs and wild macaques on deer. The effects of land use were analyzed at various spatial scales and a model selection procedure (generalized mixed model) was used to examine the effects of factors on density and daily activity pattern of deer at each spatial scale....

  18. Effective spatial scales for evaluating environmental determinants of population density in Yakushima macaques

    Agetsuma, Naoki; Koda, Ryosuke; Tsujino, Riyou; Agetsuma-Yanagihara, Yoshimi
    Population densities of wildlife species tend to be correlated with resource productivity of habitats. However, wildlife density has been greatly modified by increasing human influences. For effective conservation, we must first identify the significant factors that affect wildlife density, and then determine the extent of the areas in which the factors should be managed. Here, we propose a protocol that accomplishes these two tasks. The main threats to wildlife are thought to be habitat alteration and hunting, with increases in alien carnivores being a concern that has arisen recently. Here, we examined the effect of these anthropogenic disturbances, as well...

  19. Diel habitat-use patterns of commercially important fishes in a marine protected area in the Philippines

    Honda, Kentaro; Uy, Wilfredo H; Baslot, Darwin I; Pantallano, Allyn Duvin S; Nakamura, Yohei; Nakaoka, Masahiro
    The diel habitat-use patterns of commercially mportant fishes in a small marine protected area (MPA) (0.31 km2) containing coral reef and seagrass habitats were examined by passive acoustic telemetry during 2011 and 2012. The occurrence patterns of the target fishes both inside and outside the MPA were also observed. Thirty individuals from 6 species (20.2 to 41.4 cm fork length) were caught, acoustically tagged and released inside the MPA, and 4 to 210 d of tracking data were then obtained from 28 detected fishes. Lutjanus monostigma, Lethrinus atkinsoni, and Lethrinus obsoletus were found to mostly inhabit the coral reef. The...

  20. Involvement of hormones in olfactory imprinting and homing in chum salmon

    Ueda, Hiroshi; Nakamura, Shingo; Nakamura, Taro; Inada, Kaoru; Okubo, Takashi; Furukawa, Naohiro; Murakami, Reiichi; Tsuchida, Shigeo; Zohar, Yonathan; Konno, Kotaro; Watanabe, Masahiko
    The olfactory hypothesis for salmon imprinting and homing to their natal stream is well known, but the endocrine hormonal control mechanisms of olfactory memory formation in juveniles and retrieval in adults remain unclear. In brains of hatchery-reared underyearling juvenile chum salmon (Oncorhynchus keta), thyrotropin-releasing hormone gene expression increased immediately after release from a hatchery into the natal stream, and the expression of the essential NR1 subunit of the N-methyl-D-aspartate receptor increased during downstream migration. Gene expression of salmon gonadotropin-releasing hormone (sGnRH) and NR1 increased in the adult chum salmon brain during homing from the Bering Sea to the natal hatchery....

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