2022/04/12 更新

写真a

ヒョウドウ フジオ
兵藤 不二夫
HYODO Fujio
所属
環境生命科学学域 准教授
職名
准教授
外部リンク

学位

  • 博士(理学) ( 京都大学 )

研究分野

  • ライフサイエンス / 生態学、環境学

学歴

  • 京都大学大学院   理学研究科博士課程   生物科学専攻

    1999年4月 - 2002年3月

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  • 京都大学大学院   理学研究科修士課程   生物科学専攻

    1997年4月 - 1999年3月

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  • 京都大学    

    1993年4月 - 1997年3月

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経歴

  • 岡山大学   環境生命学研究科   准教授

    2019年4月 - 現在

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  • 岡山大学   異分野融合先端研究コア   准教授

    2013年4月 - 2019年3月

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  • 岡山大学   異分野融合先端研究コア   テニュアトラック助教

    2009年1月 - 2013年3月

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  • スウェーデン農科大学   日本学術振興会海外特別研究員

    2007年5月 - 2009年1月

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  • 総合地球環境学研究所   プロジェクト研究員

    2006年4月 - 2007年4月

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  • 総合地球環境学研究所   日本学術振興会特別研究員(PD)

    2003年4月 - 2006年3月

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  • 総合地球環境学研究所   技術補佐員

    2002年4月 - 2003年3月

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▼全件表示

 

論文

  • Topography is more important than forest type as a determinant for functional trait composition of Collembola community

    Takuo Hishi, Rieko Urakawa, Seikoh Saitoh, Yuka Maeda, Fujio Hyodo

    Pedobiologia   90   150776 - 150776   2022年3月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier BV  

    DOI: 10.1016/j.pedobi.2021.150776

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  • Stable- and radio-isotopes and a bait-choice experiment reveal changes in feeding habits of the ant community during primary succession

    Fujio Hyodo, Hiroshi O. Tanaka

    Ecological Entomology   2022年

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    掲載種別:研究論文(学術雑誌)  

    Ants play important roles in trophic dynamics through their functions, ranging from herbivores to predators. However, little is known about whether the ant community modifies diet preferences and feeding habits during primary succession. We performed a bait-choice experiment and analyses of stable carbon and nitrogen isotopes (δ13C and δ15N) and radiocarbon (Δ14C) of ants at four study sites that underwent primary succession on lava flows created by four volcanic eruptions approximately 70, 100, 230, and 540 years ago in Sakurajima, Japan. The ant community increasingly preferred plant-based diets over animal-based diets as the primary succession proceeded, likely because the ants attempted to balance nutrition through compensatory feeding according to diet availability. The δ13C values showed that the ants depended largely on carbon from C4 plants at the young sites with no canopy trees. The δ15N values of ants consistently differed among the species, suggesting that each species maintained the proportion of plant- and animal-based diets during succession. The baseline-corrected δ15N values of the ants were significantly higher at the youngest site than at the older sites; this probably reflects intraguild predation or reliance on aerial prey from surrounding older sites, which exhibited a higher δ15N-baseline partly due to the colonisation of nitrogen-fixing plants. The Δ14C values show that the two ant species examined had older diet ages, by approximately 2 years, at the old sites than those at the young sites, indicating their greater dependence on the detritus food web.

    DOI: 10.1111/een.13129

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  • Verification of the accuracy of the recent 50 years of tree growth and long-term change in intrinsic water-use efficiency using xylem Δ14C and δ13C in trees in an aseasonal tropical rainforest

    Tomoaki Ichie, Shuichi Igarashi, Ryo Yoshihara, Kanae Takayama, Tanaka Kenzo, Kaoru Niiyama, Nur Hajar Zamah Shari, Fujio Hyodo, Ichiro Tayasu

    Methods in Ecology and Evolution   2022年

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    掲載種別:研究論文(学術雑誌)  

    Growth analysis based on tree-ring chronology is difficult in trees in aseasonal tropical rain forests, because annual growth rings may be unclear or completely absent. Fortunately, tree growth history recorded in xylem tissue is capable of providing valuable information on the responses of trees and forests to past and present environmental changes, including global warming. We have developed a new technique for aseasonal tropical forest trees which derives their growth rates from xylem Δ14C, and verified its accuracy. We also determined, from xylem δ13C, the intrinsic water-use efficiency (iWUE) in the past 50 years. We analysed changes in xylem Δ14C and δ13C in 23 canopy trees of 12 species in 6 families growing in Pasoh Forest Reserve, Malaysia; each stem diameter at breast height (DBH) was recorded 14 times from 1969 to 2011. We found a significant positive relationship between the growth rates determined by 14C dating and the past DBH data. On the other hand, leaf-internal CO2 (Ci) content did not change with increasing atmospheric CO2 (Ca). Thus, the iWUE increased significantly over the last 50 years in all the families and species tested. This study showed that the simultaneous measurements of xylem Δ14C and δ13C could reveal a long-term change in tree growth and iWUE during the past 50 years with high accuracy in various species and/or individuals in aseasonal tropical rainforests exhibiting high species diversity.

    DOI: 10.1111/2041-210X.13823

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  • Survival rate, chemical and microbial properties of oak seedlings planted with or without oak forest soils in a black locust forest of a dryland

    Chikae Tatsumi, Takeshi Taniguchi, Fujio Hyodo, Sheng Du, Ryunosuke Tateno, Norikazu Yamanaka

    Forests   12 ( 6 )   2021年6月

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    掲載種別:研究論文(学術雑誌)  

    Native tree species are frequently unable to effectively grow in non-native tree cultivation scenarios. In the Loess Plateau, China, it is difficult to find native oak (Quercus liaotungensis) seedlings in non-native black locust forests. Black locust is an arbuscular mycorrhizal (AM) tree, but oak is an ectomycorrhizal (ECM) tree. Plants highly depend on their symbiotic mycorrhizal fungi to take up water, nitrogen (N) and other nutrients. We hypothesized that black locust forests would not provide ECM inoculum to oak seedlings, limiting their water and nutrient uptake, which would be improved by ECM inoculum. Here, we (1) sowed seeds, with or without oak forest soils, (2) transplanted seedlings collected in oak forests, with or without oak forest soils, and (3) planted seedlings germinated in autoclaved or unautoclaved oak forest soils. We measured the survival and growth rate for all three experiments, along with chemical properties, and root ECM colonization. Oak seeds sowed with oak forest soils had higher mycorrhizal colonization, leaf N concentrations and survival rate, and lower root δ13C than the seeds sowed without oak forest soils. Planting with oak forest soils also increased the survival rate of the germinated seedlings, but not the transplanted seedlings. Overall, our study suggested that the use of oak forest soils in the black locust forest to improve the water and N uptake of oak seedlings by providing the ECM inoculum, resulting in a high survival rate. Our study also implies that the method of sowing seeds was effortless and effectively compared to transplanting wild/nursery seedlings.

    DOI: 10.3390/f12060669

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  • Linkage of fine and coarse litter traits to soil microbial characteristics and nitrogen mineralization across topographic positions in a temperate natural forest

    Tomohiro Yokobe, Fujio Hyodo, Ryunosuke Tateno, Naoko Tokuchi

    Plant and Soil   459 ( 1-2 )   261 - 276   2021年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Aims: Topographic positions within a natural forest can considerably influence litter traits, soil microbial characteristics, and nitrogen (N) mineralization, causing plant–soil feedbacks. Despite the high abundance of coarse litter (woody debris and coarse roots) in forest ecosystems, most studies have focused on linkages between fine litter (leaves and fine roots) and N dynamics and/or the soil microbial community. Methods: We investigated the association of fine and coarse litter with soil microbial biomass, community structure, and N mineralization at upper and lower slope positions on sedimentary rocks in a temperate forest dominated by Fagus crenata. Results: Greater coarse litter abundance and litter C-to-N ratio, and lower soil microbial biomass, bacterial abundance, and N mineralization potential were found in upper positions than in lower positions. Among litter traits, coarse litter abundance and litter C-to-N ratio were the best predictors of the microbial biomass and fungal-to-bacterial dominance, possibly due to differences in climatic stress among plant communities. Microbial traits were the best predictors of N mineralization potential. Conclusions: Fine litter traits and coarse litter abundance are likely linked to soil microbial characteristics and N mineralization in natural forests with variable topography.

    DOI: 10.1007/s11104-020-04759-y

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    その他リンク: http://link.springer.com/article/10.1007/s11104-020-04759-y/fulltext.html

  • Arbuscular Mycorrhizal Community in Roots and Nitrogen Uptake Patterns of Understory Trees Beneath Ectomycorrhizal and Non-ectomycorrhizal Overstory Trees 国際誌

    Chikae Tatsumi, Fujio Hyodo, Takeshi Taniguchi, Weiyu Shi, Keisuke Koba, Keitaro Fukushima, Sheng Du, Norikazu Yamanaka, Pamela Templer, Ryunosuke Tateno

    Frontiers in Plant Science   11   583585 - 583585   2021年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nitrogen (N) is an essential plant nutrient, and plants can take up N from several sources, including via mycorrhizal fungal associations. The N uptake patterns of understory plants may vary beneath different types of overstory trees, especially through the difference in their type of mycorrhizal association (arbuscular mycorrhizal, AM; or ectomycorrhizal, ECM), because soil mycorrhizal community and N availability differ beneath AM (non-ECM) and ECM overstory trees (e.g., relatively low nitrate content beneath ECM overstory trees). To test this hypothesis, we examined six co-existing AM-symbiotic understory tree species common beneath both AM-symbiotic black locust (non-ECM) and ECM-symbiotic oak trees of dryland forests in China. We measured AM fungal community composition of roots and natural abundance stable isotopic composition of N (δ N) in plant leaves, roots, and soils. The root mycorrhizal community composition of understory trees did not significantly differ between beneath non-ECM and ECM overstory trees, although some OTUs more frequently appeared beneath non-ECM trees. Understory trees beneath non-ECM overstory trees had similar δ N values in leaves and soil nitrate, suggesting that they took up most of their nitrogen as nitrate. Beneath ECM overstory trees, understory trees had consistently lower leaf than root δ N, suggesting they depended on mycorrhizal fungi for N acquisition since mycorrhizal fungi transfer isotopically light N to host plants. Additionally, leaf N concentrations in the understory trees were lower beneath ECM than the non-ECM overstory trees. Our results show that, without large differences in root mycorrhizal community, the N uptake patterns of understory trees vary between beneath different overstory trees. 15 15 15

    DOI: 10.3389/fpls.2020.583585

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  • Diet niche segregation of co-occurring larval stages of mesopelagic and commercially important fishes in the Osumi Strait assessed through morphological, DNA metabarcoding, and stable isotope analyses

    Gen Kume, Toru Kobari, Junya Hirai, Hiroumi Kuroda, Tsutomu Takeda, Mutsuo Ichinomiya, Tomohiro Komorita, Maki Aita-Noguchi, Fujio Hyodo

    Marine Biology   168 ( 1 )   2021年1月

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    掲載種別:研究論文(学術雑誌)  

    The Osumi Strait and its neighboring waters are major spawning grounds for commercially important small pelagic and coastal fish in the Pacific coastal area of Japan. Mesopelagic fish larvae are also abundant here, co-occurring with the larvae of commercial species. However, it is unknown whether these fish groups compete for prey. We examined the diet of four commercial fish groups (Engraulis japonicus, Trachurus japonicus, Triglidae spp., and Sebastiscus spp.) and two mesopelagic species (Sigmops gracilis, Myctophum asperum) during their larval stages to determine whether they had the same prey source. Morphological analysis and DNA metabarcoding of gut contents showed that the main prey species of all six fish groups were calanoid copepods. However, results from metabarcoding differed greatly from morphological analysis, showing that appendicularians were abundant in the guts of S. gracilis, M. asperum, and Sebastiscus spp. This may be because the methods differ in how they determine prey composition, with morphological analysis relying on counts of identifiable prey parts and metabarcoding being only a semi-quantitative method. In addition, appendicularians might be underestimated by metabarcoding analysis due to variation in genome size, copy number of target genes, and primer mismatches. Stable isotope analysis supported the importance of appendicularians as prey for S. gracilis, M. asperum, and Sebastiscus spp. Our results indicate that the two mesopelagic species and Sebastiscus spp. may compete for prey, but E. japonicus, T. japonicus, and Triglidae spp. occupy niches different from those of the two mesopelagic species. Our results imply that the trophic pathway via appendicularians may support the feeding of dominant mesopelagic species and enable coexistence with commercial species in the study area.

    DOI: 10.1007/s00227-020-03810-x

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  • Potential sources of ammonium-nitrogen in the coastal groundwater determined from a combined analysis of nitrogen isotope, biological and geological parameters, and land use

    Anna Fadliah Rusydi, Shin Ichi Onodera, Mitsuyo Saito, Fujio Hyodo, Morihiro Maeda, Khori Sugianti, Sunarya Wibawa

    Water (Switzerland)   13 ( 1 )   2021年1月

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    掲載種別:研究論文(学術雑誌)  

    The origin of ammonium-nitrogen in Indonesian coastal groundwater has not been intensively examined, meanwhile the elevated concentration remains a concern. This research aims at tracing the potential sources of ammonium-nitrogen in the groundwater of Indramayu, Indonesia where groundwater is vital for livelihood. From results, a combined examination of nitrogen isotope, coliform bacteria, land-use, and geology confirmed the natural and anthropogenic origins of ammonium-nitrogen in the groundwater. In the brackish-water aquaculture region, groundwater has δ N values from +1.8 to +4.8‰ signifying that ammonium-nitrogen is derived from mineralization of organic nitrogen to ammonium. Furthermore, ammonium has a significantly positive relationship with sodium indicating the exchangeable ammonium is mobilized to groundwater via cation exchange. Meanwhile ammonium-nitrogen from anthropogenic waste was detected in agricultural and residential region. The groundwater has more varied δ N values, from −2.9 to +16.1‰, which implies attenuation of ammonium-nitrogen from several sources namely manure, mineral fertilizer, sewage, and pit latrines. Also, the presence of E. coli confirms the indication of human and animal waste contamination. However, since ammonium has no relationship with sodium, cation exchange is not feasible and ammonium-nitrogen flows into the groundwater from anthropogenic sources along with liquid wastes. 15 15 NH4 NH4

    DOI: 10.3390/w13010025

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  • Changes in stable nitrogen isotopes of plants, bulk soil and soil dissolved N during ecosystem retrogression in boreal forest

    Fujio Hyodo, Yu Takebayashi, Akiko Makabe, David A. Wardle, Keisuke Koba

    Ecological Research   36 ( 3 )   420 - 429   2021年

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    掲載種別:研究論文(学術雑誌)  

    Stable nitrogen isotope ratios (δ N) of plants and soil have been used to study changes in the N cycle during ecosystem succession and retrogression. However, little is known about how δ N of soil mineral N and dissolved organic N (DON) change during retrogression, despite their potential to inform on processes contributing to N loss. Here, we examined the δ N of NH and DON together with δ N of the dominant plant species and bulk soil across a 5,000-year-old retrogressive chronosequence of forested islands in northern Sweden. The δ N of bulk soil N, NH and DON did not change greatly during retrogression, suggesting that there are no major losses of N from the system. The δ N of NH and DON was significantly correlated with that of bulk soil N across islands, indicating that bulk soil N is an important determinant of the δ N of dissolved soil N. The δ N of DON was significantly higher than those of NH and bulk soil N, probably because of the inclusion of microbial N to the DON fraction. Despite the lack of changes in δ N of soil N as retrogression proceeded, the δ N of most plant species increased. These results suggest that despite the relative importance of the three underlying mechanisms involved is unclear, the N resources of plants change in response to retrogression: they have an increasing reliance on DON, a decreasing dependence on N transferred from the mycorrhizal fungi and reduced reliance on N from surface soil layers as retrogression proceeds. 15 15 15 + 15 15 + 15 + 15 15 + 15 15 4 4 4 4

    DOI: 10.1111/1440-1703.12208

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  • 元素分析計連結型安定同位体比質量分析計の簡易改造による微量試料炭素窒素安定同位体比測定

    木庭啓介, 木下桂, 大西雄二, 福島慶太郎, 尾坂兼一, 松尾奈緒子, 舟川一穂, 瀬古祐吾, 目戸綾乃, 平澤理世, 小川奈々子, 兵藤不二夫, 由水千景

    RADIOISOTOPES (Web)   70 ( 4 )   2021年

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  • Constraints on the jumping and prey-capture abilities of ant-mimicking spiders (Salticidae, Salticinae, Myrmarachne) 査読

    Yoshiaki Hashimoto, Tomoji Endo, Takeshi Yamasaki, Fujio Hyodo, Takao Itioka

    Scientific Reports   10 ( 1 )   2020年12月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    <title>Abstract</title>
    Accurate morphological ant mimicry by <italic>Myrmarachne</italic> jumping spiders confers strong protective benefits against predators. However, it has been hypothesized that the slender and constricted ant-like appearance imposes costs on the hunting ability because their jumping power to capture prey is obtained from hydraulic pressure in their bodies. This hypothesis remains to be sufficiently investigated. We compared the jumping and prey-capture abilities of seven <italic>Myrmarachne</italic> species and non-myrmecomorphic salticids collected from tropical forests in Malaysian Borneo and northeastern Thailand. We found that the mimics had significantly reduced abilities compared with the non-mimics. The analysis using geometric morphometric techniques revealed that the reduced abilities were strongly associated with the morphological traits for ant mimicry and relatively lower abilities were found in <italic>Myrmarachne</italic> species with a more narrowed form. These results support the hypothesis that the jumping ability to capture prey is constrained by the morphological mimicry and provide a new insight into understanding the evolutionary costs of accurate mimicry.

    DOI: 10.1038/s41598-020-75010-y

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    その他リンク: http://www.nature.com/articles/s41598-020-75010-y

  • Volcanic deposits affect soil nitrogen dynamics and fungal-bacterial dominance in temperate forests 査読

    Tomohiro Yokobe, Fujio Hyodo, Naoko Tokuchi

    SOIL BIOLOGY & BIOCHEMISTRY   150   108011 - 108011   2020年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Volcanic deposits increase soil organic carbon storage. However, little is known about the effect of volcanic deposits on forest soil nitrogen (N) dynamics and microbial communities. We explored gross and net N transformation rates and microbial community structure using a phospholipid fatty acid (PLFA) method across eight forests with soils derived from different parent material in Japan. Volcanic mineral soils had approximately three-fold greater total N and inorganic N contents and gross nitrification, ammonium immobilization, and nitrate immobilization rates that were one order of magnitude higher than in non-volcanic soils. Moreover, volcanic mineral soils had a 1.7-fold lower N turnover rate, which was estimated as net N mineralization rate per soil N. This was likely caused by a higher gross N immobilization rate, potentially due to the mineral traits of volcanic soils. Volcanic mineral soils had approximately four- and three-fold greater microbial biomass-N and bacterial PLFA contents, respectively, and the fungal:bacterial PLFA ratio was lower in volcanic mineral soils than in non-volcanic soils. Microbial community structure, analyzed using non-metric multidimensional scaling, was distinct between volcanic and non-volcanic soils, and was significantly affected by soil characteristics. This study demonstrates that aside from soil carbon storage, volcanic deposits are related to increases in soil N immobilization, N content, bacterial biomass, and N transformation rates in forest ecosystems.

    DOI: 10.1016/j.soilbio.2020.108011

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  • A new species of the genus Agorius (Araneae: Salticidae) from Sarawak, Borneo 査読

    Takeshi Yamasaki, Yoshiaki Hashimoto, Tomoji Endo, Fujio Hyodo, Itioka Takao, Paulus Meleng

    Acta Arachnologica   69 ( 1 )   37 - 41   2020年6月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Arachnological Society of Japan  

    DOI: 10.2476/asjaa.69.37

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  • Stable and radio-isotopic signatures reveal how the feeding habits of ants respond to natural secondary succession in a cool-temperate forest

    H. O. Tanaka, T. F. Haraguchi, I. Tayasu, F. Hyodo

    Insectes Sociaux   66   37 - 46   2019年2月

  • How can we quantitatively study insects whose larvae live beneath the forest floor? A case study at an experimental long-term log-removal site in Japan

    Tomonori Tsunoda, Fujio Hyodo, Daisuke Sugiura, Nobuhiro Kaneko, Satoshi N. Suzuki

    Entomological Science   22   275 - 282   2019年1月

  • Stable isotope analysis reveals the importance of plant-based diets for tropical ant-mimicking spiders

    Fujio Hyodo, Takeshi Yamasaki, Takuya Iwasa, Takao Itioka, Tomoji Endo, Yoshiaki Hashimoto

    Entomological Science   21   461 - 468   2018年12月

  • New species of the ant-mimicking genus Myrmarachne MacLeay, 1839 (Araneae: Salticidae) from Sarawak, Borneo

    Takeshi Yamasaki, Yoshiaki Hashimoto, Tomoji Endo, Fujio Hyodo, Takao Itioka, Paulus Meleng

    Zootaxa   4521 ( 3 )   335 - 356   2018年11月

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    掲載種別:研究論文(学術雑誌)  

    DOI: 10.11646/zootaxa.4521.3.2

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  • Foraging association between myxomycetes and fungal communities on coarse woody debris

    Yu Fukasawa, Yu Fukasawa, Fujio Hyodo, Shin ichi Kawakami

    Soil Biology and Biochemistry   121   95 - 102   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.soilbio.2018.03.006

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  • Seasonal effects on microbial community structure and nitrogen dynamics in temperate forest soil

    Tomohiro Yokobe, Fujio Hyodo, Naoko Tokuchi

    Forests   9 ( 3 )   2018年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3390/f9030153

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  • 野外操作実験で解き明かす「樹上性」の適応的意義~木登りカタツムリサッポロマイマイを例として

    佐伯いく代, 丹羽慈, 長田典之, 兵藤不二夫, 太田民久, 大石善隆, 日浦勉

    Venus   75 ( 1/4 )   A.21‐A.22   2017年11月

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    記述言語:日本語  

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  • Radiocarbon analysis reveals expanded diet breadth associates with the invasion of a predatory ant

    Wataru Suehiro, Fujio Hyodo, Hiroshi O. Tanaka, Chihiro Himuro, Tomoyuki Yokoi, Shigeto Dobata, Benoit Guenard, Robert R. Dunn, Edward L. Vargo, Kazuki Tsuji, Kenji Matsuura

    SCIENTIFIC REPORTS   7   2017年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Invasions are ecologically destructive and can threaten biodiversity. Trophic flexibility has been proposed as a mechanism facilitating invasion, with more flexible species better able to invade. The termite hunting needle ant Brachyponera chinensis was introduced from East Asia to the United States where it disrupts native ecosystems. We show that B. chinensis has expanded dietary breadth without shifting trophic position in its introduced range. Transect sampling of ants and termites revealed a negative correlation between the abundance of B. chinensis and the abundance of other ants in introduced populations, but this pattern was not as strong in the native range. Both termite and B. chinensis abundance were higher in the introduced range than in native range. Radiocarbon (C-14) analysis revealed that B. chinensis has significantly younger 'diet age', the time lag between carbon fixation by photosynthesis and its use by the consumer, in the introduced range than in the native range, while stable isotope analyses showed no change. These results suggest that in the introduced range B. chinensis remains a termite predator but also feeds on other consumer invertebrates with younger diet ages such as herbivorous insects. Radiocarbon analysis allowed us to elucidate cryptic dietary change associated with invasion success.

    DOI: 10.1038/s41598-017-15105-1

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  • Adaptive significance of arboreality: field evidence from a tree-climbing land snail

    Ikuyo Saeki, Shigeru Niwa, Noriyuki Osada, Fujio Hyodo, Tamihisa Ohta, Yoshitaka Oishi, Tsutom Hiura

    ANIMAL BEHAVIOUR   127   53 - 66   2017年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

    Arboreality has evolved in a wide range of taxa, but its adaptive significance has rarely been examined in natural ecosystems. Euhadra brandtii sapporo is an arboreal land snail distributed in a restricted area of Hokkaido, Japan. We hypothesized that arboreality provides the species with significant survival advantages, which we tested via field observations and experiments. A monitoring census showed that E. b. sapporo hibernates in winter in the ground litter, climbs into the canopy in early spring and returns to the ground in late autumn. This seasonal movement appears to be effective for escaping from predation by ground-dwelling carabine beetles, whose activity was high during the summer based on a pitfall-trap census. Manipulative field experiments were conducted to compare survival rates in arboreal and ground-dwelling environments. We collected 120 E. b. sapporo individuals in summer and tethered 40 in tree canopies and 80 on the ground; half those on the ground were covered by baskets to prevent predation by large animals. The survival rate after 11 days was highest in the canopy, followed by that on the ground with a basket and was lowest on the ground without a basket. Predation was the main cause of death, but some died from other causes. Similar results were obtained in autumn, except for higher survival rates of the ground treatments. Analyses of carbon and nitrogen isotope ratios suggest that the land snail uses epiphytic lichens and mosses as food resources. In conclusion, arboreality has a marked advantage in reducing mortality in E. b. sapporo and is probably supported by food availability as well. (C) 2017 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

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  • Recent progress in ecological studies of soil fauna

    Motohiro Hasegawa, Saori Fujii, Satoshi Kaneda, Hiroshi Ikeda, Takuo Hishi, Fujio Hyodo, Makoto Kobayashi

    Japanese Journal of Ecology   67 ( 2 )   95 - 118   2017年1月

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    記述言語:日本語   出版者・発行元:一般社団法人 日本生態学会  

    DOI: 10.18960/seitai.67.2_95

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  • Variations in lignin-derived phenols in sediments of Japanese lakes over the last century and their relation to watershed vegetation

    Fujio Hyodo, Michinobu Kuwae, Naoko Sasaki, Ryoma Hayashi, Wataru Makino, Soichiro Kusaka, Narumi K. Tsugeki, Seiji Ishida, Hajime Ohtsuki, Kohei Omoto, Jotaro Urabe

    ORGANIC GEOCHEMISTRY   103   125 - 135   2017年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Lignins have been used as a biomarker to explore changes in terrestrial organic matter input into lakes and to investigate past watershed vegetation. Burial of organic carbon (OC) in lake sediments, an important component of the global C cycle, is likely associated with the terrestrial OC input. However, few studies have explored changes in terrestrial C input into lakes in the last century. Furthermore, the relationship between lignin phenol compositions and watershed vegetation remains poorly examined. In this study, we examined changes in OC concentrations, OC mass accumulation rates (MAR), and lignin phenol compositions over the last century in sediments from six lakes in Japan that differ in watershed land-use and vegetation. The sediments were dated using Pb-210 and Cs-137, and showed increased OC concentrations and MARs in three lowland lakes over the last century. This pattern was not found in three mountain lakes. In one of the lowland lakes, lignin phenol concentrations normalized to OC did not change during the periods with high OC concentrations and MARs. This indicates that not only eutrophication but also enhanced terrestrial OC input could lead to greater burial of OC. The lignin phenol compositions did not show clear trends over the last century in most of the lakes examined. The ratios of syringyl to vanillyl phenols and the lignin phenol vegetation index had significant relationships with proportions of angiosperms in watershed vegetation. These results demonstrate that lignin phenols are useful in inferring recent as well as past changes in lake watershed environments. (c) 2016 Elsevier Ltd. All rights reserved.

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  • A new species of the genus Sphecotypus O. Pickard-Cambridge, 1895 from Borneo, with a comparison with the holotype of S. birmanicus (Thorell, 1897) (Araneae, Corinnidae) 査読

    Yamasaki, T, Hashimoto, Y, Endo, T, Hyodo, F, Itioka, T, Tavano, M

    Annali del Museo Civico di Storia Naturale Giacomo Doria   110   21 - 32   2017年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Homogeneous diet of contemporary Japanese inferred from stable isotope ratios of hair

    Soichiro Kusaka, Eriko Ishimaru, Fujio Hyodo, Takashi Gakuhari, Minoru Yoneda, Takakazu Yumoto, Ichiro Tayasu

    SCIENTIFIC REPORTS   6   2016年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    The globalization of food production and distribution has homogenized human dietary patterns irrespective of geography, but it is uncertain how far this homogenization has progressed. This study investigated the carbon and nitrogen isotope ratios in the scalp hair of 1305 contemporary Japanese and found values of -19.4 +/- 0.6% and 9.4 +/- 0.6% (mean +/- SD), respectively. Within Japan, the inter-regional differences for both isotope ratios was less than 1%, which indicates low dietary heterogeneity among prefectural divisions. The carbon and nitrogen isotope ratios of the hair showed a significant correlation with the results of questionnaires on self-reported dietary habits. The carbon isotope ratios from Japan were lower than those in samples from the USA but higher than those in samples from Europe. These differences stem from the varying dietary proportions of food products originally derived from C-3 and C-4 plants. The dietary variation of Japan is as small as those of Europe and USA and smaller than those of some Asian countries. These results indicate that dietary homogeneity has progressed in Japan, which may indicate the influence from the spread of the Western-style diet and food globalization, although dietary heterogeneity among countries is still preserved.

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  • Effects of remnant primary forests on feeding habits of ants in a secondary forest in Sarawak, Malaysia: An isotopic study

    Fujio Hyodo, Keiko Kishimoto-Yamada, Masayuki Matsuoka, Hiroshi O. Tanaka, Yoshiaki Hashimoto, Reiichiro Ishii, Takao Itioka

    Food Webs   6   48 - 54   2016年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fooweb.2016.02.002

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  • Carbon and nitrogen isotopes reveal feeding habits of arthropods in tropical rain forests

    Fujio Hyodo

    Japanese Journal of Ecology   66 ( 2 )   421 - 428   2016年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:一般社団法人 日本生態学会  

    DOI: 10.18960/seitai.66.2_421

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  • A new species of the genus Castoponera (Araneae, Corinnidae) from Sarawak, Borneo, with comparison to a related species

    Takeshi Yamasaki, Yoshiaki Hashimoto, Tomoji Endo, Fujio Hyodo, Takao Itioka

    ZOOKEYS   2016 ( 596 )   13 - 25   2016年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PENSOFT PUBL  

    A new species of the genus Castoponera Deeleman-Reinhold, 2001, Castoponera christae sp. n., is described here. The species is closely related to C. lecythus Deeleman-Reinhold, 2001, but can be distinguished by the structures of the male palp and the female genitalia.

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  • Changes in aboveground and belowground properties during secondary natural succession of a cool-temperate forest in Japan

    Hyodo, F., Haraguchi, T.F., Hirobe, M., Tateno, R.

    Journal of Forest Research   21 ( 4 )   170 - 177   2016年

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    掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s10310-016-0526-5

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  • Pattern of co-occurrence between ant-mimicking jumping spiders and sympatric ants in a Bornean tropical rainforest

    Yoshiaki Hashimoto, Tomoji Endo, Takao Itioka, Fujio Hyodo, Takashi Yamasaki, Maryati Mohamed

    RAFFLES BULLETIN OF ZOOLOGY   64   70 - 75   2016年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATL UNIV SINGAPORE, SCHOOL BIOLOGICAL SCIENCES  

    To evaluate the pattern of co-occurrence between ant-mimicking jumping spiders and sympatric ants in a tropical rainforest, we sampled these arthropods and also non-mimicking jumping spiders by net-sweeping from the understory vegetation in Sabah, Malaysian Borneo. We collected the spiders and ants from a total of 594 sample points, with ants occurring in 445 points (79.4%), non-mimicking jumping spiders in 308 (51.9%), Agorius ant-mimicking spiders in 40 (6.7%), and Myrmarachne ant-mimicking spiders in 59 (9.9%). Frequencies of occurrence of non-mimicking jumping spiders showed no significant difference in relation to ant-occurrence, whereas both of the ant-mimicking spider genera occurred significantly more frequently with ants. Agorius spiders co-occurred with a wider variety of different ant genera, compared to Myrmarachne, but logistic regression analyses and a null model test showed no specific associations between Agorius spiders and the sympatric ant genera. The mimetic resemblances of Agorius spiders are considered to be much less ant-like than those of Myrmarachne spiders, because their constriction of the cephalothorax is not as obvious as in Myrmarachne. These data provide support for the multi-model hypothesis (Edmunds 2000), which predicted that a poor ant-mimic should occur in ranges of many different ants, compared to good ant-mimic.

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  • Use of stable carbon and nitrogen isotopes in insect trophic ecology

    Fujio Hyodo

    ENTOMOLOGICAL SCIENCE   18 ( 3 )   295 - 312   2015年7月

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    記述言語:英語   出版者・発行元:WILEY-BLACKWELL  

    Insects are the most diverse organisms and often the most abundant animals in some ecosystems. Despite the importance of their functional roles and of the knowledge for conservation, the trophic ecology of many insect species is not fully understood. In this review, I present how stable carbon (C) and nitrogen (N) isotopes have been used to reveal the trophic ecology of insects over the last 30years. The isotopic studies on insects have used differences in C isotope ratios between C-3 and C-4 plants, along vertical profiles of temperate and tropical forest stands, and between terrestrial and aquatic resources. These differences enable exploration of the relative importance of the food resources, as well as movement and dispersal of insects across habitats. The C-13-enrichment (approximately 3 parts per thousand) caused by saprotrophic fungi can allow the estimation of the importance of fungi in insect diets. Stable N isotopes have revealed food resource partitioning across diverse insect species above and belowground. Detritivorous insects often show a large trophic enrichment in C-13 (up to 3 parts per thousand) and N-15 (up to 10 parts per thousand) relative to the food substrates, soil organic matter. These values are greater than those commonly used for estimation of trophic level. This enrichment likely reflects the prevalence of soil microbial processes, such as fungal development and humification, influencing the isotopic signatures of diets in detritivores. Isotope analysis can become an essential tool in the exploration of insect trophic ecology in terms of biogeochemical C and N cycles, including trophic interactions, plant physiological and soil microbial processes.

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  • Dependence of diverse consumers on detritus in a tropical rain forest food web as revealed by radiocarbon analysis

    Fujio Hyodo, Takashi Matsumoto, Yoko Takematsu, Takao Itioka

    FUNCTIONAL ECOLOGY   29 ( 3 )   423 - 429   2015年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    Energy and material flows from dead organic matter, or detritus, to generalist predators have a potential impact on the food web dynamics. However, little is known about how commonly generalist predators depend on detritivorous prey, or the detritus on which the detritivores have fed in terrestrial food webs. To examine this, we measured the diet ages of terrestrial invertebrate and vertebrate consumers (&gt;30 species) at multiple trophic levels in a tropical rain forest, with a particular focus on ants and termites by using radiocarbon (C-14). Here, we defined diet age as the lag time between the primary production and the utilization by consumer organisms. The diet ages varied from 0 to &gt;50years and corresponded to known feeding habits of the consumers. Herbivores such as bees, butterflies, a frugivorous bird and bat, and nectar-feeding ants had young diet ages (0-3years). Meanwhile, detritivores such as termites had old diet ages, which increased according to the food resources in the order of litter (6years), soil (10years) and wood (19years). The diet ages of predators such as wolf spiders, hunting wasps, army ants, tree shrews and an insectivorous bat were intermediate (2-8years), indicating the dependence of many predators on detritivores. Because known dietary components of the predators include herbivores and detritivores, the intermediate ages likely indicate the coupling of energy and material flows between plant-based and detritus-based food webs. Diet ages of soil-feeding termite and army ant differed significantly, although a previous study reported that their nitrogen isotope ratios were indistinguishable despite the differing feeding habits. This indicates that radiocarbon can distinguish the two factors, trophic enrichment and the below-ground processes (humification), both of which could influence the nitrogen isotopic signatures of the terrestrial consumers. Our results show that radiocarbon would provide insights into structures of terrestrial food webs as well as time frame of energy and material flows through the webs.

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  • Faunal studies of sap beetles (Coleoptera: Nitidulidae) in primary and secondary tropical rainforests in the middle reaches of the Baram River Basin, Borneo.

    J. Yoshimoto, S. T. Hisamatsu, K. Kishimoto-Yamada, F. Hyodo, Y. Hashimoto, T. Itioka

    30 ( 2 )   77 - 84   2015年

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    記述言語:英語   掲載種別:研究論文(大学,研究機関等紀要)  

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  • A new genus and species of myrmecophilous brentid beetle (Coleoptera: Brentidae) inhabiting the myrmecophytic epiphytes in the Bornean rainforest canopy

    Munetoshi Maruyama, Luca Bartolozzi, Yoko Inui, Hiroshi O. Tanaka, Fujio Hyodo, Usun Shimizu-Kaya, Yoko Takematsu, Takuo Hishi, Takao Itioka

    ZOOTAXA   3786 ( 1 )   73 - 78   2014年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:MAGNOLIA PRESS  

    Pycnotarsobrentus inuiae Maruyama & Bartolozzi, gen. nov. and sp. nov. (Brentinae: Eremoxenini) is described from the Lambir Hills National Park, Borneo (Sarawak, Malaysia) based on specimens collected from Crematogaster difformis F. Smith, 1857 ant nests in the myrmecophytic epiphytic ferns Platycerium crustacea Copel. and Lecanopteris ridleyi H. Christ. A second species of Pycnotarsobrentus is known from Malaysia but is represented by only one female and consequently not yet described pending discovery of a male. Pycnotarsobrentus belongs to the tribe Eremoxenini and shares some character states with the African genus Pericordus Kolbe, 1883. No species of Eremoxenini with similar morphological modifications are known from the Oriental region.

    DOI: 10.11646/zootaxa.3786.1.5

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  • Use of carbon-13 and carbon-14 natural abundances for stream food web studies

    Naoto F. Ishikawa, Fujio Hyodo, Ichiro Tayasu

    Ecological Research   28 ( 5 )   759 - 769   2013年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s11284-012-1003-z

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  • Changes in stable nitrogen and carbon isotope ratios of plants and soil across a boreal forest fire chronosequence

    Fujio Hyodo, Soichiro Kusaka, David A. Wardle, Marie-Charlotte Nilsson

    PLANT AND SOIL   367 ( 1-2 )   111 - 119   2013年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Nitrogen (N) and carbon (C) isotopic signatures (delta N-15 and delta C-13) serve as powerful tools for understanding temporal changes in ecosystem processes, but how these signatures change across boreal forest chronosequences is poorly understood.
    The delta N-15, delta C-13, and C/N ratio of foliage of eight dominant plant species, including trees, understory shrubs, and a moss, as well as humus, were examined across a 361 years fire-driven chronosequence in boreal forest in northern Sweden.
    The delta C-13 and C/N ratio of plants and humus increased along the chronosequence, suggesting increasing plant stress through N limitation. Despite increasing biological N fixation by cyanobacteria associated with feather mosses, delta N-15 showed an overall decline, and delta N-15 of the feather moss and associated vascular plants diverged over time from that of atmospheric N-2.
    Across this chronosequence the N fixed by cyanobacteria is unlikely to be used by mosses and vascular plants without first undergoing mineralization and mycorrhizal transport, which would cause a change in delta N-15 signature due to isotopic fractionation. The decreasing trend of delta N-15 suggests that as the chronosequence proceeds, the plants may become more dependent on N transferred from mycorrhizal fungi or from N deposition.

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  • Effects of remnant primary forests on ant and dung beetle species diversity in a secondary forest in Sarawak, Malaysia

    Keiko Kishimoto-Yamada, Fujio Hyodo, Masayuki Matsuoka, Yoshiaki Hashimoto, Masahiro Kon, Teruo Ochi, Seiki Yamane, Reiichiro Ishii, Takao Itioka

    JOURNAL OF INSECT CONSERVATION   17 ( 3 )   591 - 605   2013年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Tropical landscape structures have been transformed into mosaic structures consisting of small patches of primary and secondary forests, and areas of other land use. Diversity of insect assemblages is often higher in primary forests than in surrounding secondary forests. However, little is known about how the primary forests affect diversity in surrounding secondary forests in a landscape. In Sarawak, Malaysia, the typical landscape in areas from which lowland tropical rainforests had originally spread consists mainly of primary and secondary forests, with small areas of cultivation. In this study, we examined how the proportion of remnant primary forests in a landscape affects species diversity and species composition of ants and dung beetles in Macaranga-dominated secondary forests. The proportions were quantified based on remote-sensing data at various spatial scales, ranging from 100- to 5,000-m radius from each of the target forests. We found that the proportions of remnant primary forests within a 100-m radius had a significant positive effect on ant species diversity, and those within 100-, 300-, and 500-m radii significantly affected species compositions. However, the proportions of remnant primary forests had no significant relationship with dung beetle diversity, while those within 100- and 1,000-m radii had significant effects on species composition. The different responses to the remnant primary forests are likely to be related to differences in the movement and dispersal traits between the two taxa.

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  • Possible ideas on carbon and nitrogen trophic fractionation of food chains: a new aspect of food-chain stable isotope analysis in Lake Biwa, Lake Baikal, and the Mongolian grasslands

    Eitaro Wada, Reiichiro Ishii, Maki Noguchi Aita, Nanako O. Ogawa, Ayato Kohzu, Fujio Hyodo, Yoshihiro Yamada

    ECOLOGICAL RESEARCH   28 ( 2 )   173 - 181   2013年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER JAPAN KK  

    Trophic fractionation of carbon and nitrogen isotopes (Delta delta C-13, Delta delta N-15) was examined using previously complied databases for food chains in Lake Biwa, Lake Baikal, and Mongolian grassland. The following two features were clarified: (1) For each ecosystem, the ratios of trophic fractionation of carbon and nitrogen isotopes (Delta delta N-15/Delta delta C-13) throughout food chain could be obtained as the slope of linear regression line on the delta N-15-delta C-13 plot. (2) Further, analysis of covariance (ANCOVA) revealed the slopes on delta N-15-delta C-13 were not significantly different among these various ecosystems and allowed us to have the regression by setting delta N-15 as the response variable: delta N-15 = 1.61 delta C-13 + [ecosystem specific constant] with standard errors of [+/- 0.41] and [+/- 9.7] for the slope and the intercept, respectively. It was suggested that the slope of the regression (or the ratio Delta delta N-15/Delta delta C-13) could be applicable to more complicated food webs in case nitrogen and carbon isotope ratios of primary producers can be assumed constant in space and time within the ecosystems. The results from simple linear regression analyses coincided well with the ANCOVA results for these ecosystems, although there was some discrepancy between the results of the two statistical analyses. Possible factors that govern the linear relationship between delta N-15 and delta C-13 along a food chain are discussed together with a new scope for the stable isotope food chain analyses.

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  • Changes in stable nitrogen and carbon isotope ratios of plants and soil across a boreal forest fire chronosequence

    Fujio Hyodo, Soichiro Kusaka, David A. Wardle, Marie-Charlotte Nilsson

    PLANT AND SOIL   364 ( 1-2 )   315 - 323   2013年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Nitrogen (N) and carbon (C) isotopic signatures (delta N-15 and delta C-13) serve as powerful tools for understanding temporal changes in ecosystem processes, but how these signatures change across boreal forest chronosequences is poorly understood.
    The delta N-15, delta C-13, and C/N ratio of foliage of eight dominant plant species, including trees, understory shrubs, and a moss, as well as humus, were examined across a 361 years fire-driven chronosequence in boreal forest in northern Sweden.
    The delta C-13 and C/N ratio of plants and humus increased along the chronosequence, suggesting increasing plant stress through N limitation. Despite increasing biological N fixation by cyanobacteria associated with feather mosses, delta N-15 showed an overall decline, and delta N-15 of the feather moss and associated vascular plants diverged over time from that of atmospheric N-2.
    Across this chronosequence the N fixed by cyanobacteria is unlikely to be used by mosses and vascular plants without first undergoing mineralization and mycorrhizal transport, which would cause a change in delta N-15 signature due to isotopic fractionation. The decreasing trend of delta N-15 suggests that as the chronosequence proceeds, the plants may become more dependent on N transferred from mycorrhizal fungi or from N deposition.

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  • Use of radiocarbon to estimate diet ages of earthworms across different climate regions

    Fujio Hyodo, Tomoko Uchida, Nobuhiro Kaneko, Ichiro Tayasu

    APPLIED SOIL ECOLOGY   62   178 - 183   2012年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Natural abundance of radiocarbon (C-14) has been applied to estimate the turnover time of soil carbon (C) across different climate regions. However, despite the important functional role played by soil animals in decomposition processes, little is known about variation in their C-14 concentrations across different climate regions. In this study, we measured C-14 concentrations of earthworms collected in three forests in Japan. In addition, we also reviewed C-14 data on earthworms that were previously reported. We used these data to test whether the diet ages (defined as time elapsed since C in the diet of earthworms was fixed from atmospheric CO2 by photosynthesis) differed according to feeding habits and across study sites in various climate regions ranging from cool temperate forest to tropical savanna. Multiple regression analysis showed that the diet ages of earthworms were significantly affected by both feeding habits and study sites. The diet ages of endogeic (soil-feeding) earthworms (8.3 +/- 0.4 years, mean SE) were significantly older than those of epigeic (litter-feeding) earthworms (2.6 +/- 0.5 years), with anecic (litter-/soil-feeding) earthworms (5.7 +/- 0.9 years) having intermediate diet ages. When mean diet age was compared for each feeding habit, only that of endogeic earthworms differed significantly across the sites. However, it did not necessarily become younger in warmer climate regions. These results either suggest that the degree of decomposition of soil organic matter used by earthworms differs among the study sites, or that the difference in the turnover time of Soil organic C used by earthworms across the sites is relatively small and variable due to factors other than temperature, such as soil texture and vegetation. (C) 2012 Elsevier B.V. All rights reserved.

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  • Nitrogen niches revealed through species and functional group removal in a boreal shrub community

    Michael J. Gundale, Fujio Hyodo, Marie-Charlotte Nilsson, David A. Wardle

    ECOLOGY   93 ( 7 )   1695 - 1706   2012年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    Most theories attempting to explain the coexistence of species in local communities make fundamental assumptions regarding whether neighbors exhibit competitive, neutral, or positive resource-use interactions; however, few long-term data from naturally assembled plant communities exist to test these assumptions. We utilized a 13-year experiment consisting of factorial removal of three shrub species (Vaccinium myrtillus, V. vitis-idaea, and Empetrum hermaphroditum) and factorial removal of two functional groups (tree roots and feather mosses) to assess how neighbors affect N acquisition and growth of each of the three shrub species. The removal plots were established on each of 30 lake islands in northern Sweden that form a natural gradient of resource availability. We tested the hypotheses that: (1) the presence of functionally similar neighbors would reduce shrub N acquisition through competition for a shared N resource; (2) the removal of functional groups would affect shrub N acquisition by altering the breadth of their niches; and (3) soil fertility would influence the effects of neighbor removals. We found that the removal of functionally similar neighbors (i.e., other shrub species) usually resulted in higher biomass and biomass N, with the strength of these effects varying strongly with site fertility. Shrub species removals never resulted in altered stable N isotope ratios (delta N-15), suggesting that the niche breadth of the three shrubs was unaffected by the presence of neighboring shrub species. In the functional group removal experiment, we found positive effects of feather moss removal on V. myrtillus biomass and biomass N, and negative effects on E. hermaphrotium N concentration and V. vitis-idaea biomass and biomass N. Tree root removal also caused a significant shift in foliar delta N-15 of V. myrtillus and altered the delta N-15, biomass, and biomass N of E. hermaphroditum. Collectively, these results show that the resource acquisition and niche breadth of the three shrub species are often affected by neighbors, and further that both the identity of neighbors and site fertility strongly determine whether these interactions are positive, negative, or neutral. These findings have implications for understanding species coexistence and the reciprocal relationships between productivity and species diversity in this ecosystem.

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  • Variation in nitrogen isotopic composition in the Selenga river watershed, Mongolia

    Fujio Hyodo, Junko Nishikawa, Ayato Kohzu, Noboru Fujita, Izuru Saizen, Jamsran Tsogtbaatar, Choijilsuren Javzan, Mangaa Enkhtuya, Davaadorj Gantomor, Narantsetsegiin Amartuvshin, Reiichiro Ishii, Eitaro Wada

    LIMNOLOGY   13 ( 1 )   155 - 161   2012年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER JAPAN KK  

    The stable nitrogen (N) isotope ratio (delta N-15) has been used to examine the anthropogenic N input (i.e., septic water, wastewater, and manure) to aquatic ecosystems, because anthropogenic N generally has a delta N-15 signature distinct from that found in nature. Aquatic organisms and the derived organic matter such as sediments are reported to become increasingly enriched in N-15 as the human population density increases in watersheds. However, little is known about the relationship in steppe ecosystems, where the livestock population is greater than that of humans. Here, we conducted a preliminary study in the Selenga river mainstream watershed in Mongolia, which covers an area of approximately 300,000 km(2). A multiple regression analysis revealed that the delta N-15 of the riverine sediment was significantly affected by the human population density and more significantly by livestock population density. The population density, including both humans and livestock, significantly influenced delta N-15 of the macrophytic Potamogeton spp. The results showed that delta N-15 of riverine organic matter can be an indicator of the human and livestock population density, which is likely associated with the status of N cycles in livestock-dominated watersheds.

    DOI: 10.1007/s10201-011-0351-7

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  • 琵琶湖湖底堆積物に記録された過去100年間のスギ花粉年間堆積量の変化

    林 竜馬, 兵藤 不二夫, 占部 城太郎, 高原 光

    日本花粉学会会誌   58 ( 1 )   5 - 17   2012年

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    記述言語:日本語   出版者・発行元:日本花粉学会  

    DOI: 10.24524/jjpal.58.1_5

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  • 笠岡湾干拓地における水質汚濁の現状と 安定同位体比を用いた汚濁機構解析 査読

    前田守弘, 浅野裕一, 兵藤不二夫, 中島泰弘, 藤原拓, 永禮英明, 赤尾聡史

    土木学会論文集G(環境)   67 ( 7 )   III_213 - III_222   2011年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Linear relationship between carbon and nitrogen isotope ratios along simple food chains in marine environments

    Maki Noguchi Aita, Kazuaki Tadokoro, Nanako O. Ogawa, Fujio Hyodo, Reiichiro Ishii, S. Lan Smith, Toshiro Saino, Michio J. Kishi, Sei-Ichi Saitoh, Eitaro Wada

    JOURNAL OF PLANKTON RESEARCH   33 ( 11 )   1629 - 1642   2011年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    To examine the relationship between carbon and nitrogen stable isotope (SI) ratios (delta C-13 and delta N-15) of zooplankton, we analyzed samples collected bimonthly from March to October 2009, from the euphotic layers of the Oyashio current along the A-line in the western North Pacific. Isotopic ratios of higher trophic levels such as predatory zooplankton and/or long-lived zooplankton varied little with season, while those of short-lived zooplankton were variable on the delta N-15-delta C-13 map. We also analyzed preserved samples taken from the warm-core ring 86-B derived from the Kuroshio extension region. Although the zooplankton groups in the two regions exhibited different values in delta N-15, the delta N-15 versus delta C-13 slopes for each ecosystem do not show significant differences. Statistical analysis conducted together with previously published data from the Antarctic Ocean and the Gulf of Alaska suggested a similar delta N-15 versus delta C-13 slope throughout the four regions. We attributed this common slope to physiological aspects of feeding processes (e. g. the kinetic isotope effects inherent in the processes of amino acid synthesis). The common pattern for all four oceanic regions suggests that SIs may be used to elucidate general patterns in ecosystems and biogeochemical cycles.

    DOI: 10.1093/plankt/fbr070

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  • Feeding habits of Hymenoptera and Isoptera in a tropical rain forest as revealed by nitrogen and carbon isotope ratios

    F. Hyodo, Y. Takematsu, T. Matsumoto, Y. Inui, T. Itioka

    INSECTES SOCIAUX   58 ( 3 )   417 - 426   2011年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER BASEL AG  

    Despite the recognition of the functional role of Hymenoptera (ants, bees and wasps) and Isoptera (termites) in tropical ecosystems, their detailed feeding habits are not well known. To examine the feeding habits of these groups, we measured nitrogen (N) and carbon (C) stable isotope ratios (delta(15)N and delta(13)C) of hymenopterans (12 families, a parts per thousand yen16 genera and a parts per thousand yen32 species) and isopterans (one family and 10 species) collected in a tropical rain forest, Sarawak, Malaysia. We compared the isotopic signatures of these insects to those previously reported for other consumers collected in the same forest. The delta(15)N and delta(13)C values of these insects overlapped with those of the other consumers, indicating that they have access to diverse C and N sources in the forest. The delta(15)N values of ants and termites indicated that their feeding habits range along a continuum from herbivory (i.e. dependent on honeydew and nectar) to predation and from wood-feeders to soil-feeders, respectively. In addition, the delta(15)N values of wasps varied greatly from -0.1aEuro degrees (Braconidae sp.) to 8.6aEuro degrees (Bembix sp.), suggesting that their feeding habits also range from omnivory to predation. The ant species Camponotus gigas had delta(13)C values similar to those of invertebrate detritivores and omnivores rather than to those of invertebrate herbivores, although the diet of this species consists mostly of honeydew. This discrepancy suggests that the ant uses carbohydrates as an energy source, the isotopic signatures of which are not well retained in the body tissues. Values of both delta(15)N and delta(13)C of the predatory army ant Leptogenys diminuta and the soil-feeding termite Dicuspiditermes nemorosus did not differ significantly, indicating that both trophic level and the humification of feeding substrates can increase the isotopic signatures of terrestrial consumers.

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  • 伏見城跡遺跡から出土した江戸時代人骨の安定同位体による食性分析

    日下 宗一郎, 五十嵐 健行, 兵藤 不二夫, 藤澤 珠織, 片山 一道

    Anthropological science. Japanese series : journal of the Anthropological Society of Nippon : 人類學雜誌   119 ( 1 )   9 - 17   2011年6月

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    記述言語:日本語   出版者・発行元:日本人類学会  

    江戸時代は、急激な人口増加とその後の人口安定、また陸・海路による交易網の発達によって特徴づけられ、コメや野菜や魚介類を主要な食物としていたと言われる。そのような江戸時代の人々の食性を、遺跡から出土した人骨を用いて実証しようとするのが本研究である。伏見城跡遺跡(京都市)より出土した江戸時代人骨および動物骨からコラーゲンを抽出して、炭素および窒素の安定同位体比を測定した。合計で27個体(男性9個体、女性12個体、子ども6個体)の人骨を分析に用いた。それにより、伏見江戸時代人の食性、その性差を検討することを目的とした。江戸時代の伏見の人々は、タンパク質源を淡水魚類に強く依存した食生活、もしくは陸上生態系から得られるC3植物と海産あるいは淡水魚類などを主たるタンパク質源とする食生活を送っていた可能性を示した。江戸時代の都市では、食生活が米、野菜、魚介類からなり、アワやヒエ、キビなどC4植物の消費が少ないとする古記録を考慮に入れると、後者の食生活像が支持される。また、男性の炭素同位体比は女性よりも高く、より多くの海産魚類や貝類などを摂取していた可能性がある。また、年齢が上がると子どもの窒素同位体比は下がる傾向があり、これは母乳の摂取と離乳の開始に関連していると考えられる。(著者抄録)

    DOI: 10.1537/asj.119.9

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  • Long-term aboveground and belowground consequences of red wood ant exclusion in boreal forest

    David A. Wardle, Fujio Hyodo, Richard D. Bardgett, Gregor W. Yeates, Marie-Charlotte Nilsson

    ECOLOGY   92 ( 3 )   645 - 656   2011年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ECOLOGICAL SOC AMER  

    Despite their ubiquity, the role of ants in driving ecosystem processes both aboveground and belowground has been seldom explored, except within the nest. During 1995 we established 16 ant exclusion plots of approximately 1.1 x 1.1 m, together with paired control plots, in the understory layer of a boreal forest ecosystem in northern Sweden that supports high densities of the mound-forming ant Formica aquilonia, a red wood ant species of the Formica rufa group. Aboveground and belowground measurements were then made on destructively sampled subplots in 2001 and 2008, i.e., 6 and 13 years after set-up. While ant exclusion had no effect on total understory plant biomass, it did greatly increase the relative contribution of herbaceous species, most likely through preventing ants from removing their seeds. This in turn led to higher quality resources entering the belowground subsystem, which in turn stimulated soil microbial biomass and activity and the rates of loss of mass and carbon (C) and nitrogen (N) from litter in litterbags placed in the plots. This was accompanied by losses of similar to 15% of N and C stored in the humus on a per area basis. Ant exclusion also had some effects on foliar stable isotope ratios for both C and N, most probably as a consequence of greater soil fertility. Further, exclusion of ants had multitrophic effects on a microbe-nematode soil food web with three consumer trophic levels and after six years promoted the bacterial-based relative to the fungal-based energy channel in this food web. Our results point to a major role of red wood ants in determining forest floor vegetation and thereby exerting wide-ranging effects on belowground properties and processes. Given that the boreal forest occupies 11% of the Earth&apos;s terrestrial surface and stores more C than any other forest biome, our results suggest that this role of ants could potentially be of widespread significance for biogeochemical nutrient cycling, soil nutrient capital, and sequestration of belowground carbon.

    DOI: 10.1890/10-1223.1

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  • Carbon and nitrogen stable isotope analysis on the diet of Jomon populations from two coastal regions of Japan

    Soichiro Kusaka, Fujio Hyodo, Takakazu Yumoto, Masato Nakatsukasa

    JOURNAL OF ARCHAEOLOGICAL SCIENCE   37 ( 8 )   1968 - 1977   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

    We report on a stable isotope paleodietary reconstruction of Jomon populations in Japan during the Middle to Final Jomon period (ca. 5000-2300 years BP), focusing on dietary differences within and among populations and between regions. Carbon and nitrogen isotope analysis was performed on human and faunal bone collagen from six coastal sites along the Inland Sea in the Sanyo (Ota, Funamoto, and Tsukumo) region and along Mikawa Bay and the Pacific Ocean in the Tokai (Kawaji, Yoshigo, and lnariyama) region. We found that carbon and nitrogen isotope ratios were positively correlated, indicating that the Jomon people consumed a mixed diet of marine (shellfish and marine fish) and terrestrial (C(3) plants and terrestrial mammals) protein. In the Ota samples (n = 25, during the Middle Jomon period, 5000-4000 years BP), sex was one of the main reasons for the intra-population dietary variation. Ota males consumed greater amounts of marine food, while Ota females consumed greater amounts of terrestrial food; these dissimilar diets may have been related to the sexual division of labor. Significant inter-population dietary differences were found, which may have been related to differences in age or site location. Notably, the two coastal regions showed clear isotopic differences. Nitrogen isotope ratios of individuals from the Sanyo region were significantly higher than ratios of individuals from the Tokai region. The individuals in the Sanyo region might have consumed a diet high in aquatic foods, particularly high trophic level marine fish, whereas the individuals in the Tokai region might have consumed a lot of marine shellfish. Another possible reason for the regional isotopic difference might have been different baseline of nitrogen isotope ratios of the marine ecosystems. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jas.2010.03.002

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  • Linking aboveground and belowground food webs through carbon and nitrogen stable isotope analyses

    Fujio Hyodo, Ayato Kohzu, Ichiro Tayasu

    ECOLOGICAL RESEARCH   25 ( 4 )   745 - 756   2010年7月

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    記述言語:英語   出版者・発行元:SPRINGER TOKYO  

    Carbon and nitrogen stable isotope ratios (delta(13)C and delta(15)N) have been used for more than two decades in analyses of food web structure. The utility of isotope ratio measurements is based on the observation that consumer delta(13)C values are similar (&lt; 1aEuro degrees difference) to those of their diet, while consumer delta(15)N values are about 3aEuro degrees higher than those of their diet. The technique has been applied most often to aquatic and aboveground terrestrial food webs. However, few isotope studies have examined terrestrial food web structure that includes both above- and belowground (detrital) components. Here, we review factors that may influence isotopic signatures of terrestrial consumers in above- and belowground systems. In particular, we emphasize variations in delta(13)C and delta(15)N in belowground systems, e.g., enrichment of (13)C and (15)N in soil organic matter (likely related to soil microbial metabolism). These enrichments should be associated with the high (13)C (similar to 3aEuro degrees) enrichment in belowground consumers relative to litter and soil organic matter and with the large variation in delta(15)N (similar to 6aEuro degrees) of the consumers. Because such enrichment and variation are much greater than the trophic enrichment generally used to estimate consumer trophic positions, and because many general predators are considered dependent on energy and material flows from belowground, the isotopic variation in belowground systems should be taken into account in delta(13)C and delta(15)N analyses of terrestrial food webs. Meanwhile, by measuring the delta(13)C of key predators, the linkage between above- and belowground systems could be estimated based on observed differences in delta(13)C of primary producers, detritivores and predators. Furthermore, radiocarbon ((14)C) measurements will allow the direct estimation of the dependence of predators on the belowground systems.

    DOI: 10.1007/s11284-010-0719-x

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  • The structure of a food web in a tropical rain forest in Malaysia based on carbon and nitrogen stable isotope ratios

    Fujio Hyodo, Takashi Matsumoto, Yoko Takematsu, Tamaki Kamoi, Daisuke Fukuda, Michiko Nakagawa, Takao Itioka

    JOURNAL OF TROPICAL ECOLOGY   26   205 - 214   2010年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CAMBRIDGE UNIV PRESS  

    Carbon and nitrogen stable isotope ratios (delta(13)C and delta(15)N) have been used to study the structure of food webs. However, few studies have examined how a terrestrial food web can be depicted by this technique. We measured delta(13)C and delta(15)N in various consumers of four trophic groups (detritivores, herbivores. omnivores and predators), including vertebrates and invertebrates (14 orders, &gt;= 24 families). as well as canopy and understorey leaves in a tropical rain forest in Malaysia. We found that. delta(13)C and delta(15)N of the consumers differed significantly among the trophic groups. The predators had significantly, higher delta(13)C than the herbivores, and were similar in delta(13)C to the detritivores, suggesting that most. predators examined depend largely, on below-ground food webs. delta(15)N was higher in predators than detritivores by about, 3 parts per thousand. The comparison of delta(13)C in plant materials and herbivores suggests that most. herbivores are dependent on C fixed in the canopy, layers. The vertebrates had significantly higher delta(15)N and delta(13)C than the invertebrates of the same trophic group. likely reflecting differences in the physiological processes and/or feeding habits. This study indicates that stable isotope techniques can help better Understanding of the terrestrial food webs in terms of both trophic level and the linkage of above and below-ground systems.

    DOI: 10.1017/S0266467409990502

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  • A strontium isotope analysis on the relationship between ritual tooth ablation and migration among the Jomon people in Japan

    Soichiro Kusaka, Atsushi Ando, Takanori Nakano, Takakazu Yumoto, Eriko Ishimaru, Minoru Yoneda, Fujio Hyodo, Kazumichi Katayama

    JOURNAL OF ARCHAEOLOGICAL SCIENCE   36 ( 10 )   2289 - 2297   2009年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

    Distinct patterns can be discerned in the extensive ritual tooth ablation found among the human skeletal remains of the Late-Final Jomon period (ca. 3200-2800 cal BP) in Japan. Based on comparative observations of sex and grave patterns in the skeletal remains, two major patterns in ritual tooth ablation, termed type 41 and type 2C, have been assigned to locals and immigrants, respectively. In order to test this hypothesis, strontium (Sr) isotope ((87)Sr/(86)Sr) analyses were performed on human skeletal remains from the Yoshigo shell mound in Aichi Prefecture, central Japan. Plants in the surrounding area were also examined to illustrate the geographic (87)Sr/(86)Sr distribution. The Sr isotopic variation in human tooth enamel ((87)Sr/(86)Sr = 0.70868-0.71028) was greater than that in human bones ((87)Sr/(86)Sr = 0.70871-0.70943). Individuals with higher Sr isotope ratios in their tooth enamel than seawater Sr values of 0.7092 can be identified as immigrants (36% of population). The presence of these isotopically identified immigrants between both type 2C and type 41 individuals does not support the previous hypothesis. The intra-population (87)Sr/(86)Sr distribution of tooth enamel of type 2C individuals showed a significantly higher mean ratio than that of type 41 individuals, suggesting a higher proportion of immigrants among the former. (C) 2009 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jas.2009.06.013

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  • Effect of ecosystem retrogression on stable nitrogen and carbon isotopes of plants, soils and consumer organisms in boreal forest islands

    Fujio Hyodo, David A. Wardle

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   23 ( 13 )   1892 - 1898   2009年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JOHN WILEY & SONS LTD  

    In the prolonged absence of catastrophic disturbance, ecosystem retrogression occurs, and this involves increased nutrient limitation, and reduced aboveground and belowground ecosystem processes rates. Little is known about how the nitrogen and carbon stable isotope ratios (delta(15)N and delta(13)C) of plants, soils and consumer organisms respond to retrogression in boreal forests. We investigated a 5000 year chronosequence of forested islands in the boreal zone of northern Sweden, for which the time since lightning-induced wildfire increases with decreasing island size, leading to ecosystem retrogression. For this system, tissue delta(15)N of three abundant plant species (Betula pubescens, Vaccinium myrtillus and Pleurozium schreberi) and humus all increased as retrogression proceeded. This is probably due to enhanced ecosystem inputs of N by biological fixation, and greater dependency of the plants on organic N during retrogression. The delta(13)C of B. pubescens and plant-derived humus also increased during retrogression, probably through nutrient limitation increasing plant physiological stress. Unlike the plants, delta(15)N of invertebrates (lycosid spiders and ants) did not increase during retrogression, probably because of their partial dependence on aquatic-derived prey that had a variable delta(15)N signature. The delta(13)C of the invertebrates increased as retrogression proceeded and converged towards that of an aquatic prey source (chironomid flies), suggesting increased dependence on aquatic-derived prey during retrogression. These results show that measurement of delta(15)N and delta(13)C of plants, soils, and consumers across the same environmental gradient can provide insights into environmental factors that drive both the aboveground and belowground subsystems, as well as the linkages between them. Copyright (C) 2009 John Wiley & Sons, Ltd.

    DOI: 10.1002/rcm.4095

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  • Flower orientation enhances pollen transfer in bilaterally symmetrical flowers

    Atushi Ushimaru, Ikumi Dohzono, Yasuoki Takami, Fujio Hyodo

    OECOLOGIA   160 ( 4 )   667 - 674   2009年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Zygomorphic flowers are usually more complex than actinomorphic flowers and are more likely to be visited by specialized pollinators. Complex zygomorphic flowers tend to be oriented horizontally. It is hypothesized that a horizontal flower orientation ensures effective pollen transfer by facilitating pollinator recognition (the recognition-facilitation hypothesis) and/or pollinator landing (the landing-control hypothesis). To examine these two hypotheses, we altered the angle of Commelina communis flowers and examined the efficiency of pollen transfer, as well as the behavior of their visitors. We exposed unmanipulated (horizontal-), upward-, and downward-facing flowers to syrphid flies (mostly Episyrphus balteatus), which are natural visitors to C. communis. The frequency of pollinator approaches and landings, as well as the amount of pollen deposited by E. balteatus, decreased for the downward-facing flowers, supporting both hypotheses. The upward-facing flowers received the same numbers of approaches and landings as the unmanipulated flowers, but experienced more illegitimate landings. In addition, the visitors failed to touch the stigmas or anthers on the upward-facing flowers, leading to reduced pollen export and receipt, and supporting the landing-control hypothesis. Collectively, our data suggested that the horizontal orientation of zygomorphic flowers enhances pollen transfer by both facilitating pollinator recognition and controlling pollinator landing position. These findings suggest that zygomorphic flowers which deviate from a horizontal orientation may have lower fitness because of decreased pollen transfer.

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  • Nitrogen-stable isotopic signatures of basal food items, primary consumers and omnivores in rivers with different levels of human impact

    Ayato Kohzu, Ichiro Tayasu, Chikage Yoshimizu, Atsushi Maruyama, Yukihiro Kohmatsu, Fujio Hyodo, Yukio Onoda, Akitake Igeta, Kiyoshi Matsui, Takanori Nakano, Eitaro Wada, Toshi Nagata, Yasuhiro Takemon

    ECOLOGICAL RESEARCH   24 ( 1 )   127 - 136   2009年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER TOKYO  

    We examined how nitrogen-stable isotopic signatures of food web components (basal resources, primary and lower consumers, and omnivores) in rivers change with increasing levels of human population density (HPD) in their watersheds. Samples were collected from 22 rivers flowing in the Lake Biwa basin, Japan. Among three potential resources at the base of food webs (epilithon, benthic and suspended particulate organic matter), the mean isotopic values (delta(15)N) of the epilithon (4.5-7.8%) were consistently higher than those of other items (1.9-4.2%) and displayed the most pronounced elevation (by 3.3%) with increasing HPD. The mean delta(15)N values of the individual taxa of lower consumers (bivalve, snail and caddisfly) tended to increase with increasing HPD, although the pattern and the extent of the elevation were highly variable among the taxa. These results suggest a taxon-specific feature in the N source (or sources) of lower consumers. Our data suggested that human activities (e.g. nutrient loading) potentially induce changes in the N baselines of river food webs. The major N source of bivalves appeared to be shifted from suspended particulate organic matter to other items with increasing HPD. Trophic levels of goby fish (Rhinogobius sp. OR) and shrimp (Palaemon paucidens), being estimated to be at 2.4-3.8 and 2.1-3.4, respectively, did not differ significantly among rivers with different HPD levels.

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  • Within-nest abundance of a tropical cockroach Pseudoanaplectinia yumotoi associated with Crematogaster ants inhabiting epiphytic fern domatia in a Bornean dipterocarp forest

    Yoko Inui, Hiroshi O. Tanaka, Fujio Hyodo, Takao Itioka

    JOURNAL OF NATURAL HISTORY   43 ( 19-20 )   1139 - 1145   2009年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:TAYLOR & FRANCIS LTD  

    Many epiphytic ferns in tropical forest canopies have domatia that provide habitat for arboreal arthropods such as ants. Two species of fern that were predominantly occupied by Crematogaster difformis ants were collected from the canopy of a forest in Borneo. In the fern domatia, two cockroach species, Pseudoanaplectinia yumotoi and Blatta sp., were found to live with C. difformis. Pseudoanaplectinia yumotoi were found in large numbers and accounted for approximately 20% of the total arthropod population, while Blatta sp. comprised only 1% of the arthropods living in the domatia. Behavioural experiments were conducted to evaluate the response of C. difformis workers to newly introduced cockroaches of each species and to allospecific ant workers. Crematogaster difformis workers were highly aggressive and quickly attacked allospecific workers. Both cockroach species could fend off ant attacks; however, dead Blatta sp. were often attacked by the ants while dead P. yumotoi were infrequently bothered.

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  • Use of Stable Nitrogen Isotope Signatures of Riparian Macrophytes As an Indicator of Anthropogenic N Inputs to River Ecosystems

    Ayato Kohzu, Toshihiro Miyajima, Ichiro Tayasu, Chikage Yoshimizu, Fujio Hyodo, Kiyoshi Matsui, Takanori Nakano, Eitaro Wada, Noboru Fujita, Toshi Nagata

    ENVIRONMENTAL SCIENCE & TECHNOLOGY   42 ( 21 )   7837 - 7841   2008年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    Deterioration of aquatic ecosystems resulting from enhanced anthropogenic N loading has become an issue of increasing concern worldwide, and methods are needed to trace sources of N in rivers. Because nitrate from sewage is enriched in N-15 relative to nitrate from natural Soils, delta N-15 values of stream nitrate (delta N-15(nitrate)) should be an appropriate index of anthropogenic N loading to rivers, as should the delta N-15 values of riparian plants (delta N-15(plant)) because they are consumers of nitrate. We determined the delta N-15 values of stream nitrate and six species of riparian macrophytes in 31 rivers in the Lake Biwa Basin in Japan. We then tested the correlation between these values and various land-use parameters, including the percentage of land used for residential and agricultural purposes as well as for natural areas. These delta N-15 values were significantly positively correlated with land use N that had a high N load (i.e., residential or agricultural use) and significantly negatively correlated with forest N. These findings indicate that (delta N-15 values of stream nitrate and riparian plants might be good indicators of anthropogenic inputs of nitrogen.

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  • Changes in stable isotopes, lignin-derived phenols, and fossil pigments in sediments of Lake Biwa, Japan: Implications for anthropogenic effects over the last 100 years

    Fujio Hyodo, Narumi Tsugeki, Jun ichi Azuma, Jotaro Urabe, Masami Nakanishi, Eitaro Wada

    Science of the Total Environment   403 ( 1-3 )   139 - 147   2008年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.scitotenv.2008.05.010

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  • Variability in stable isotope ratios in two Late-Final Jomon communities in the Tokai coastal region and its relationship with sex and ritual tooth ablation

    Soichiro Kusaka, Soichiro Kusaka, Takeyuki Ikarashi, Fujio Hyodo, Takakazu Yumoto, Kazumichi Katayama

    Anthropological Science   116 ( 2 )   171 - 181   2008年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1537/ase.070703

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  • Gradual enrichment of 15N with humification of diets in a below-ground food web: Relationship between 15N and diet age determined using 14C

    F. Hyodo, I. Tayasu, S. Konaté, J. E. Tondoh, P. Lavelle, E. Wada

    Functional Ecology   22 ( 3 )   516 - 522   2008年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    1. Stable nitrogen (N) isotope has been widely used to disentangle food webs and to infer trophic positions of organisms based on an assumption that the stepwise enrichment occurs along trophic levels. The enrichment of N in soil organisms with diet humification has also been reported, but the underlying mechanism has not been fully examined. 2. To examine the effect of diet humification on N, we estimated the stable N isotope ratios and diet ages of earthworms and termites. These organisms feed on organic matter with various degrees of humification, ranging from undecomposed plant materials to humified organic matter (soil organic matter), in a gallery forest and a savanna in the Ivory Coast. We defined diet age as the time elapsed since carbon (C) in the diet of earthworms and termites was fixed from atmospheric CO by photosynthesis; it was estimated by comparing the radiocarbon ( C) content of these organisms to atmospheric CO records. 3. Stable N isotope ratios increased along the humification gradient of diets, and values for earthworms and termites varied from 1.8‰ to 9.9‰ and from -1.5‰ to 15.9‰, respectively. Epigeic (litter-feeding) earthworms had younger diet ages (2-4 years), whereas endogeic (soil-feeding) earthworms generally exhibited older diet ages (5-9 years). Grass-feeding termites had young diet ages (2 years), and wood/soil-feeding termites had the oldest diet ages (c. 50 years). Soil-feeding termites were similar in diet age (7-12 years) to wood feeders (8-11 years), with the exception of one species (18-21 years) that consumes large-diameter wood. 4. A significant positive relationship was found between diet ages and stable N isotope ratios of the two groups in the savanna. This relationship held in the gallery forest when termites feeding on woody tissues were not considered. These results show that the stable N isotope ratios of organisms can increase with diet age, unless C in the diet has been stored as organic matter, such as woody tissue, that is able to age without being subject to humification processes. 5. Given that above-ground food webs are often sustained directly by material and energy flow from below-ground food webs, in addition to trophic interactions, gradual enrichment of N with the humification of below-ground diets should be considered when interpreting stable N isotope ratios of terrestrial food webs. © 2008 The Authors. 15 15 14 14 15 2 2

    DOI: 10.1111/j.1365-2435.2008.01386.x

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  • Effect of agriculture on water quality of Lake Biwa tributaries, Japan

    Takanori Nakano, Ichiro Tayasu, Yoshihiro Yamada, Takahiro Hosono, Akitake Igeta, Fujio Hyodo, Atsushi Ando, Yu Saitoh, Takuya Tanaka, Eitaro Wada, Shigeo Yachi

    SCIENCE OF THE TOTAL ENVIRONMENT   389 ( 1 )   132 - 148   2008年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    We investigated the effects of natural environments and human activity on Lake Biwa, central Japan. We determined the concentrations of 19 elements and the compositions of stable S and Sr isotopes in the main tributaries of the lake and compared them with the corresponding values obtained from the lake water during the circulation period. Results of a principal component analysis indicated that the components dissolved in the lower reaches of the tributaries can be divided into group 1 (HCO3, SO4, NO3, Ca, Mg, Sr) and group 2 components (Cl, Br, Na, K, Ba, Rb, Cs). The concentrations of group 1 components were high in the rivers of the southern area, which is urbanized and densely populated, and the eastern area, which consists of plains where agriculture predominates, compared with the rivers of the northern and western areas, which are mostly mountainous and sparsely populated. The concentrations of group 2 components tended to be high in the river water of industrial areas. The delta S-34 values of SO4 in the river water converged to 0 +/- 2 parts per thousand as the SO4 concentration increased and, excluding the areas where limestone is extensively distributed, as the HCO3 concentration increased. In particular, both the delta S-34 values (0 +/- 2 parts per thousand) and the Sr-87/Sr-86 ratios (0.7117 +/- 0.0005) fell within narrow ranges in the small and medium rivers of the eastern plain area, where rice is widely grown. These values agreed respectively with the delta S-34 values of the fertilizers used in the Lake Biwa basin and the soil-exchangeable Sr-87/Sr-86 in the eastern plain. The characteristics of water quality in the small and medium rivers of the eastern area can be explained by a model in which sulfuric, nitric, and bicarbonic acids generated by the decomposition of agricultural fertilizer and paddy rice selectively leached out alkaline-earth elements adsorbed on the soil and sediments of the plain or dissolved calcium carbonate enriched with Mg and Sr. Compared with tributary waters, the lake water was depleted in NO3, owing to denitrification, and in Mn, owing to mineralization, which occur under the redox condition of bottom sediments. Excluding NO3 and Mn, the compositions of both the dissolved elements and the Sr and S isotopes in the water of Lake Biwa can be approximately reproduced by simple mixing of the tributary water, indicating that these components provide effective indices for evaluating the relationship between the waters of the lake and its tributaries. (C) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.scitotenv.2007.08.042

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  • 大気圏核実験由来放射性炭素14を用いた生態学

    陀安一郎, 兵藤不二夫, 石川尚人

    生物の科学「遺伝」11月号   2008年

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  • Divergence times in the termite genus Macrotermes (Isoptera : Termitidae)

    R. Brandl, F. Hyodo, M. von Koff-Schmising, K. Maekawa, T. Miura, Y. Takematsu, T. Matsumoto, T. Abe, R. Bagine, M. Kaib

    MOLECULAR PHYLOGENETICS AND EVOLUTION   45 ( 1 )   239 - 250   2007年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    The evolution of fungus-growing termites is supposed to have started in the African rain forests with multiple invasions of semi-arid habitats as well as multiple invasions of the Oriental region. We used sequences of the mitochondrial Coll gene and Bayesian dating to investigate the time frame of the evolution of Macrotermes, an important genus of fungus-growing termites. We found that the genus Macrotermes consists of at least 6 distantly related clades. Furthermore, the Coll sequences suggested some cryptic diversity within the analysed African Macrotermes species. The dates calculated with the Coll data using a fossilized termite mound to calibrate the clock were in good agreement with dates calculated with COI sequences using the split between Locusta and Chortippus as calibration point which supports the consistency of the calibration points. The clades from the Oriental region dated back to the early Tertiary. These estimates of divergence times suggested that Macrotermes invaded Asia during periods with humid climates. For Africa, many speciation events predated the Pleistocene and fall in range of 6-23 million years ago. These estimates suggest that savannah-adapted African clades radiated with the spread of the semi-arid ecosystems during the Miocene. Apparently, events during the Pleistocene were of little importance for speciation within the genus Macrotermes. However, further investigations are necessary to increase the number of taxa for phylogenetic analysis. (c) 2007 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.ympev.2007.07.007

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  • The feeding habits of collembola along decomposition gradients using stable carbon and nitrogen isotope analyses

    Takuo Hishi, Fujio Hyodo, Seikoh Saitoh, Hiroshi Takeda

    SOIL BIOLOGY & BIOCHEMISTRY   39 ( 7 )   1820 - 1823   2007年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    We measured the natural stable carbon (C) and nitrogen (N) isotope ratio patterns of collembola and the organic substrates of their habitats and potential food sources in a warm temperate coniferous forest. Based on previous studies, we classified collembola into successional classes along litter decomposition gradients: early colonizers, late colonizers, and dominants-throughout. The stable C and N isotope ratios of late colonizers exceeded those of early colonizers, and those of the dominants-throughout were intermediate between early and late colonizers, which is consistent with previous studies on two macro-invertebrates, earthworms and termites. The C and N isotopic signature differences in collembola may reflect food resource partitioning along decomposition gradients. (c) 2007 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.soilbio.2007.01.028

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  • Effect of forest use on trophic levels of small mammals: an analysis using stable isotopes

    Michiko Nakagawa, Fujio Hyodo, Tohru Nakashizuka

    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE   85 ( 4 )   472 - 478   2007年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS  

    The degradation of tropical forests is progressing rapidly and its ecological effects on wild animals are a global concern. We evaluated the hypothesis that small mammals in highly degraded forest occupy higher trophic levels than those in somewhat degraded forests, as indicated by diets high in consumers such as insects, in a tropical rain forest in Sarawak, Malaysia. After correcting for differences in the delta N-15 values for primary production among the study sites, the delta N-15(corrected) values for rats and mice (Muridae) differed significantly among forest types. Rats and mice in more degraded forest had higher delta N-15(corrected) values than those in less degraded or primary forest: in contrast, treeshrews (Tupaiidae) and squirrels (Sciuridae) showed no significant differences in the delta N-15(corrected) values among forest types. We found significant positive correlations between canopy openness and the delta N-15(corrected) values for one species of squirrel and two species of rats. This hypothesis was supported for small mammals that have normal dietary preferences for plants, i.e., omnivorous rodents, but not for those that normally prefer insects, i.e., treeshrews. The delta N-15 values for omnivorous mammals may be useful as an indicator of changes in food-web structure in response to forest disturbance.

    DOI: 10.1139/Z07-026

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  • Effects of mound occupation by the meat ant Iridomyrmex sanguineus (Hymenoptera : Formicidae) on the termite Amitermes laurensis (Isoptera : Termitidae) in an Australian woodland

    Akinori Yamada, Tetsushi Inoue, Fujio Hyodo, Ichiro Tayasu, Takuya Abe

    SOCIOBIOLOGY   50 ( 1 )   1 - 9   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CALIF STATE UNIV  

    Mounds of the termite Amitermes laurensis in northern Queensland, Australia, are frequently invaded and occupied by the meat ant Iridomyrmex sanguineus, but their interactions remain unclear. In 1999, 68 A. laurensis mounds that were mapped and examined for the presence of the meat ants in 1998 were studied by destructive sampling, and the occupancy percentages of the termites were compared during the 2 years of meat ant occupation. The results indicate that the occupancy percentages of the termites in the intact mounds (79%) are significantly different from those in the mounds that were occupied by the meat ants in 1998 (58%), 1999 (42%), or both (20%). Although the mean vales showed apparent differences, no significant difference was observed in the occupancy percentages among the latter three cases. Our results suggest that the meat ants arc not lethal invaders of the termite mounds and that the recovery of the termite populations occurs after the meat ants abandon the mounds.

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  • しろかき期の強制落水による懸濁物, 窒素とリンの流出 : 圃場における流出実験

    山田 佳裕, 井桁 明丈, 中島 沙知, 三戸 勇吾, 小笠原 貴子, 和田 彩香, 大野 智彦, 上田 篤史, 兵藤 不二夫, 今田 美穂, 谷内 茂雄, 陀安 一郎, 福原 昭一, 田中 拓弥, 和田 英太郎

    陸水學雜誌   67 ( 2 )   105 - 112   2006年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:日本陸水学会  

    DOI: 10.3739/rikusui.67.105

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  • Estimation of the longevity of C in terrestrial detrital food webs using radiocarbon (C-14): how old are diets in termites?

    F Hyodo, Tayasu, I, E Wada

    FUNCTIONAL ECOLOGY   20 ( 2 )   385 - 393   2006年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BLACKWELL PUBLISHING  

    We propose that diets of consumers in a food web have various ages, where age is defined as the time elapsed since carbon (C) in the diet was fixed from atmospheric CO2 by primary producers. To examine the diet ages for primary consumers in a detrital food web, we measured the radiocarbon (C-14) content of termites collected in Thailand in 1998 and 2004. Diet ages were estimated by comparing the C-14 content of samples with records of atmospheric (CO2)-C-14, which doubled in the early 1960s as a result of nuclear weapons tests and decreased after the nuclear test ban treaty. For comparison, we measured the C-14 content of bees as primary consumers in a grazing web at the same study site. Stable carbon and nitrogen (N) isotope ratios were also analysed.
    The C-14 contents of the same species of termites decreased during the sampling interval, indicating that they used organic matter produced after the peak in atmospheric (CO2)-C-14. The diet ages were estimated to be 12-18, 7-13 and 5-9 years for the wood-feeder (Microcerotermes crassus), the soil-feeders (Dicuspiditermes makhamensis and Termes comis) and the fungus-grower (Macrotermes carbonarius), respectively. One colony of soil-feeder (T. comis), which nested in a fallen tree trunk, had exceptionally low C-14 content, and its diet age was estimated to be around 50 years. The two bee species had lower C-14 contents compared with the termites, and their diet ages were estimated to be 0 (Apis florea) and 2-4 years (Trigona sp.).
    Stable C and N isotope ratios of termites showed similar patterns as previously reported, and no clear difference was observed between 1998 and 2004. Although the bees and the fungus-growing termite had similar stable C and N isotope ratios, their diet ages differed.
    Our study suggests that radiocarbon can be used to estimate the diet ages of consumers in terrestrial food webs. Diet age should provide new insight into the trophic positions of organisms in grazing and detrital food webs and the interactions between these two webs.

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  • Sulfur and strontium isotope geochemistry of tributary rivers of Lake Biwa: implications for human impact on the decadal change of lake water quality

    T Nakanao, Tayasu, I, E Wada, A Igeta, F Hyodo, Y Miura

    SCIENCE OF THE TOTAL ENVIRONMENT   345 ( 1-3 )   1 - 12   2005年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    To study the deterioration of the water quality in Lake Biwa, Japan, over the last 40 years, we measured the concentrations and isotopic ratios of sulfur and strontium of water in 41 inflowing rivers and one discharging river. The concentrations of SO4 and Sr of inflowing rivers at downstream sites were generally high in the southern urban area and in the eastern area, where a large agricultural plain is situated, but low in the northern and western areas, whose watersheds are mountainous and with low population density. SO4 and Sr concentrations are also lower at upstream sites, which are closer to mountainous areas. Thus, the inflowing river receives large amounts of SO4 and Sr as it flows across the plain, where human activity levels are high. The delta(34)S or Sr-87/Sr-86 values of most eastern rivers at downstream sites are lower than those of water in Lake Biwa, and values become more uniform as the proportion of the plain area in the watershed increases. River water in other areas has higher values of delta(34)S or Sr-87/Sr-86 than the lake water. This result indicates that the decadal decrease of delta(34)S and Sr-87/Sr-86 in the lake water has been caused mainly by the increased flux of SO4 and Sr from rivers in the eastern plain. We assume that in the plain, sulfur, nitrogen, and organic compounds induced by human activities generate sulfuric, nitric, and organic acids in the water, which accelerate the extraction of Sr from bedrocks, leading to the generation of Sr in the river water in the area. (c) 2004 Elsevier B.V. All rights reserved.

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  • Why do bilaterally symmetrical flowers orient vertically? Flower orientation influences pollinator landing behaviour

    A Ushimaru, F Hyodo

    EVOLUTIONARY ECOLOGY RESEARCH   7 ( 1 )   151 - 160   2005年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:EVOLUTIONARY ECOLOGY LTD  

    Flower orientation is an important character influencing plant fitness. Zygomorphic flowers are known to orient vertically. We conducted field experiments in which we changed the flower angle of zygomorphic Commelina communis to determine how flower orientation affects pollinator behaviour. We confirmed that Commelina flowers oriented vertically like other zygomorphic flowers. Then, we artificially prepared control, upward- and downward-oriented flowers and exposed them to natural pollinators (syrphid flies and bumblebees). We found that the frequency of approach by syrphid flies and bumblebees was not influenced by flower angle, but there were fewer landings on downward-oriented flowers than on control and upward-oriented flowers. Moreover, the upward flower orientation increased illegitimate landings (landing on the flower without touching the stigmas or mating-related anthers) compared with controls. Thus, vertical flower orientation in zygomorphic flowers serves to control pollinator landings. Our findings suggest that deviations from vertical orientation may reduce fitness in C communis by reducing the efficiency of insect-mediated pollen transfer.

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  • Changes in crown architecture with tree height in two deciduous tree species: developmental constraints or plastic response to the competition for light?

    N Osada, R Tateno, F Hyodo, H Takeda

    FOREST ECOLOGY AND MANAGEMENT   188 ( 1-3 )   337 - 347   2004年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    We examined the crown architecture of two canopy species, Fagus crenata Blume, which is highly shade tolerant, and Quercus crispula Blume, which is less shade tolerant, in upper and lower positions on a slope in a cool-temperate forest in Japan. The purpose of this study was to investigate the relative effects of the competitive position for the light environment and developmental constraints on the crown architecture of two species that have different degrees of shade tolerance. In both species, the maximum attainable height was smaller on the upper slope than on the lower slope. The light environment brightened with increasing tree height. Trees in similar competitive position and thus similar light environments were shorter on the upper slope than on the lower slope. When we considered tree height relative to the maximum attainable height, the difference between the upper and lower slopes in the relationship of competitive position to tree height disappeared. Thus, relative tree height was a good index of the competitive position for the light environment when the trees of both slope positions were pooled. The relationships of crown depth and width to relative tree height differed between trees on the upper and lower slopes, while the relationships of crown depth and width to actual tree height were similar. This suggests that developmental constraints are more important than the competitive position in determining the crown architecture of the two species. However, variation in crown architecture was greater in Q. crispula than in F crenata, probably because of the difference in shade tolerance between the two species. (C) 2003 Elsevier B.V. All rights reserved.

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  • Abundance and biomass of termites in dead wood in a dry evergreen forest in Thailand (vol 42, pg 569, 2003) 査読

    Yamada, A; Inoue, T; Sugimoto, A; Takematsu, Y; Kumai, T; Hyodo, F; Fujita, A; Tayasu, I; Klangkaew, C; Kirtibutr, N; Kudo, T; Abe, T   43 ( 2 )   231 - 232   2004年

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  • Differential role of symbiotic fungi in lignin degradation and food provision for fungus-growing termites (Macrotermitinae : Isoptera)

    F Hyodo, Tayasu, I, T Inoue, JI Azuma, T Kudo, T Abe

    FUNCTIONAL ECOLOGY   17 ( 2 )   186 - 193   2003年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BLACKWELL PUBLISHING LTD  

    1. To investigate whether the role of symbiotic fungi in lignin degradation and food provision differs among fungus-growing termites (four species of Macrotermes , three species of Odontotermes , Hypotermes makhamensis , Ancistrotermes pakistanicus and Pseudacanthotermes militaris ), the chemical composition of fungus combs of different ages and the chitinolytic activity in the gut of termites were analysed. In addition, the carbon stable isotope ratios (delta(13) C) in old combs, worker termite tissues and fungal nodules (aggregated conidia) were compared.
    2. In Macrotermes spp., the carbohydrate : lignin ratio of the combs increased with increased comb age, but it decreased or remained the same in Odontotermes spp., H. makhamensis , A. pakistanicus and P. militaris. In contrast, the chitin : carbohydrate ratio and ash content increased more over time in the combs of Odontotermes spp., H. makhamensis , A. pakistanicus and P. militaris than in the combs of Macrotermes spp.
    3. Chitinolytic activity in the gut of workers was higher in O. takensis , H. makhamensis and A. pakistanicus than in M. annandalei .
    4. In all species examined, the delta(13) C value increased in the sequence: old combs &lt; termites &lt; fungal nodules. Based on a two-source model of delta(13) C, the contribution of fungi to termite nutrition was considered higher in Odontotermes spp., H. makhamensis , A. pakistanicus and P. militaris than in Macrotermes spp.
    5. These results suggest that symbiotic fungi play different roles among fungus-growing termites. In Macrotermes spp., the main role of symbiotic fungi is to degrade lignin, so that the termites can utilize cellulose more efficiently, whereas in Odontotermes spp., H. makhamensis , A. pakistanicus and P. militaris , it is to serve as a food source.

    DOI: 10.1046/j.1365-2435.2003.00718.x

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  • Diversity of nest types in Microcerotermes crassus (Termitinae, Termitidae, Isoptera) in a dry evergreen forest of Thailand

    Y Takematsu, T Inoue, F Hyodo, A Sugimoto, N Kirtebutr, T Abe

    SOCIOBIOLOGY   42 ( 3 )   587 - 596   2003年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CALIF STATE UNIV  

    In a dry evergreen forest of Sakaerat, Thailand, five types of nests (arboreal, epigeal, hypogeal, inquiline and nests within wood) which were built by the genus Microcerotermes were observed. Morphologically, all samples collected from five nest types belonged to the same species and were identified as Microcerotermes crassus. This indicates that a single species can build different nest types in the same locality. Furthermore, the density of nests and the relative abundance were investigated. At 99 nests per plot area (165 nests per hectare), the nest abundance and the relative abundance was very much higher than in other Southeast Asian forests.

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  • Abundance and Biomass of termites (Insecta : Isoptera) in dead wood in a dry evergreen forest in Thailand

    A Yamada, T Inoue, A Sugimoto, Y Takematsu, T Kumai, F Hyodo, A Fujita, Tayasu, I, C Klangkaew, N Kirtibutr, T Kudo, T Abe

    SOCIOBIOLOGY   42 ( 3 )   569 - 585   2003年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CALIFORNIA STATE UNIV  

    The abundance and biomass of termites in dead wood were estimated in a dry evergreen forest in Thailand. Litter and dead wood were collected within ten 2 x 2 m quadrats on a 100 m transect, and then all termites in the litter and dead wood (= termites in dead wood) were dislodged. The biomass of litter and dead wood was 2.50 kg (dry weight) m(-2), of which 76% was represented by dead wood with a diameter of ! 1 cm. A total of 239 pieces of dead wood (diameter ! I cm) were collected, and 38 of them contained termites. The frequency of termites in dead wood was significantly different between pieces with a diameter of 1-5 cm and pieces with a diameter of greater than or equal to5 cm. The abundance and biomass of termites in dead wood were 1269 termites m(-2) and 3.53 g m(-2), respectively. A total of I I species, comprising Kalotermitidae, Rhinotermitidae and Termitidae, were collected; all of them belonged to the wood/litter-feeding group. Using our previous estimation for termites in the soil and data from other studies, the abundance and biomass of termites in the dry evergreen forest were estimated to be 7794 termites m(-2) and 16.7 g m(-2), of which 16 and 21%, respectively, were represented by termites in dead wood. Our study confirmed the importance of termites in dead wood in tropical seasonal forests.

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  • Caste-specific N and C isotope ratios in fungus-growing termites with special reference to uric acid preservation and their nutritional interpretation

    Tayasu, I, F Hyodo, T Abe

    ECOLOGICAL ENTOMOLOGY   27 ( 3 )   355 - 361   2002年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BLACKWELL PUBLISHING LTD  

    1. Nitrogen and carbon isotope ratios and uric acid concentrations in fungus-growing termites (Isoptera: Termitidae: Macrotermitinae), sampled in Cameroon and Thailand, were determined in order to compare castes that are known to differ in behaviour and feeding habits.
    2. Nitrogen isotope ratios (delta(15) N) were either not significantly changed or lower in workers compared with the diet (the fungus combs), whereas carbon isotope ratios (delta(13) C) were higher in worker termites than in the fungus combs.
    3. In old workers, delta(15) N values were unexpectedly low and correlated negatively with whole-body uric acid concentrations. This indicates that older workers retain uric acid, which has a low delta(15) N value, to conserve nitrogen within the colony and, furthermore, that older colony members may ultimately be consumed by younger conspecifics.

    DOI: 10.1046/j.1365-2311.2002.00414.x

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  • Termite ecology in a dry evergreen forest in Thailand in terms of stable (δ13C and δ15N) and radio (14C, 137Cs and 210Pb) isotopes

    Ichiro Tayasu, Ichiro Tayasu, Toshio Nakamura, Hirotaka Oda, Fujio Hyodo, Yoko Takematsu, Yoko Takematsu, Takuya Abe

    Ecological Research   17 ( 2 )   195 - 206   2002年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1046/j.1440-1703.2002.00479.x

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  • Nitrogen and carbon stable isotope ratios in the sympatric Australian termites, Amitermes laurensis and Drepanotermes rubriceps (Isoptera : Termitidae) in relation to their feeding habits and the quality of their food materials

    Tayasu, I, F Hyodo, T Abe, T Inoue, AV Spain

    SOIL BIOLOGY & BIOCHEMISTRY   34 ( 3 )   297 - 301   2002年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Tissue N and C stable isotope ratios of two sympatric termite species were investigated in relation to those of their stored food materials at two savanna sites in north-eastern Australia (Woodstock and Oak Valley). At both sites, the delta(15)N values of termite tissues and the stored food materials of the litter-feeding species Amitermes laurensis were significantly greater than their equivalents in the grass-harvesting species Drepanotermes rubriceps. In addition, the carbohydrate/lignin and C/N ratios were higher and chitin/carbohydrate ratios were lower in food materials stored in the mounds of D. rubriceps. Both sets of analyses confirmed that A rubriceps assimilates less decomposed food materials than A. laurensis. Tissue delta(13)C Values indicated that both species assimilated similar proportions of C3 and C4 plant materials at the Woodstock site, but that the workers of A. laurensis assimilated a greater proportion of C3 plant material at the Oak Valley site. The delta(15) N values of termites from the Woodstock site were significantly greater than those from Oak Valley, although the differences in order at each site were consistent between species. The results indicate that N and C stable isotope ratios must be carefully compared across habitats. (C) 2002 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0038-0717(01)00181-X

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  • Effect of the soil-feeding termite, Dicuspiditermes makhamensis, on soil carbon structure in a seasonal tropical forest as revealed by CP/MAS C-13 NMR

    F Hyodo, Tayasu, I, JI Azuma, N Kirtibutr, T Abe

    SOCIOBIOLOGY   38 ( 3A )   487 - 493   2001年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CALIF STATE UNIV  

    Decomposition processes in the soil profile (L, F, A1 and A2 layer) in a seasonal tropical forest in Thailand was investigated and compared to the epigeal mound of the soil-feeding termite Dicuspiditermes makhamensis by CP/MAS C-13 NMR. The main characteristics of carbon structural changes during decomposition was the loss of carbohydrate and accumulation of recalcitrant aliphatic compounds. In terms of CP/MAS C-13 NMR, there is no clear difference between the carbon composition of the termite mound and that of the surface organic soil layer, suggesting that the effect of the soil-feeding termite is not very prominent on soil carbon structure.

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  • The abundance and biomass of subterranean termites (Isoptera) in a dry evergreen forest of northeast Thailand

    T Inoue, Y Takematsu, F Hyodo, A Sugimoto, A Yamada, C Klangkaew, N Kirtibutr, T Abe

    SOCIOBIOLOGY   37 ( 1 )   41 - 52   2001年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CALIF STATE UNIV  

    The abundance and biomass of subterranean termites were assessed in the dry evergreen forest within the Sakaerat Environmental Research Station, northeast Thailand. The samplings were carried out by pit-digging in November 1998 (during rainy season) and February 1999 (during dry season). A total of 23 species of termites, comprising 17 genera were identified. Estimated abundance was 6450 tesmites/m(2) in November and 2526 termites/m(2) in February and biomass was 10.74g/m(2) (fresh mass) in November and 5.35g/m(2) in February, although no significant difference was detected in termite abundance and biomass between rainy and dry season. In 30cm depth pit-digging, we found more than 93% of individual termites and more than 94% of total biomass within the top 20cm of soil layer in both samplings. The termite abundance and biomass within the surficial soil layer (0-10cm layer) showed no significant difference between in November and February sampling.

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  • Role of the mutualistic fungus in lignin degradation in the fungus-growing termite Macrotermes gilvus (Isoptera; Macrotermitinae)

    F Hyodo, T Inoue, JI Azuma, Tayasu, I, T Abe

    SOIL BIOLOGY & BIOCHEMISTRY   32 ( 5 )   653 - 658   2000年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    In order to investigate the role of the mutualistic fungus, Termitomyces sp., in the fungus-growing termite, Macrotermes gilvus, we applied CP/MAS C-13 NMR and selected proximate analyses to fungus comb of different ages and degrees of maturation. We found evidence that lignin degradation took place progressively in the fungus comb. In vitro digestibility of cellulose in old fungus comb, on which the termites feed, was approximately 3-fold higher than that in the fresh part. These results confirm the 'lignin degradation hypothesis' that the role of the mutualistic fungi is lo degrade lignin and enhance the digestibility of cellulose for the termites, suggesting the ability of the termite-fungus association to make extremely efficient use of plant material. (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0038-0717(99)00192-3

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  • Stable isotope ratios and uric acid preservation in termites belonging to three feeding habits in Thailand

    Tayasu, I, F Hyodo, Y Takematsu, A Sugimoto, T Inoue, N Kirtibutr, T Abe

    ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES   36 ( 3 )   259 - 272   2000年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP  

    Nitrogen and carbon stable isotope ratios and uric acid concentrations in termites sampled from a dry evergreen forest in Thailand, were determined across three kinds of feeding habits. Feeding habits of Microcerotermes crassus, which is an abundant wood-feeder, and Dicuspiditermes makhamensis, a common soil-feeding termite, were confirmed by isotopic signatures. Lichen feeding termites (Hospitalitermes birmanicus, H. bicolor and H. ataramensis) were characterized by low delta N-15 values, suggesting that they assimilated nitrogen deposited from the atmosphere. There was also a significant difference in uric acid concentrations between termites representing different feeding habits. No significant relationships were found between uric acid concentrations and delta N-15 or delta C-13 in Hospitalitermes. However, delta N-15 values were correlated with C/N ratios in H. birmanicus, except in one colony of H. ataramensis. delta C-13 values in both species were negatively correlated with C/N ratios.

    DOI: 10.1080/10256010008036386

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  • Estimation of effect of passage through the gut of a lower termite, Coptotermes formosanus Shiraki, on lignin by solid-state CP MAS C-13 NMR

    F Hyodo, J Azuma, T Abe

    HOLZFORSCHUNG   53 ( 3 )   244 - 246   1999年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WALTER DE GRUYTER & CO  

    DOI: 10.1515/HF.1999.041

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  • A new pattern of lignin degradation in the fungus comb of Macrotermes carbonarius (Isoptera, Termitidae Macrotermitinae)

    F Hyodo, J Azuma, T Abe

    SOCIOBIOLOGY   34 ( 3 )   591 - 596   1999年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CALIF STATE UNIV  

    A hypothesis on the role of the symbiotic fungi in fungus growing termites was examined on Macrotermes carbonarius, whose fungus comb had appearance different from those of other Macrotermes species reported so far. Chemical analyses of fungus comb of M. carbonarius indicated that decline of lignin concentration within the fungus comb, which has been observed in some Macrotermes species, was not observed, but the decrease was detected between the fungus combs. This new pattern of lignin degradation confirms the hypothesis that the role of the symbiotic fungi is to degrade lignin and improve cellulose digestibility.

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▼全件表示

書籍等出版物

  • 安定同位体を用いた餌資源・食物網調査法

    土居 秀幸, 兵藤 不二夫, 石川 尚人

    共立出版  2016年  ( ISBN:9784320057548

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    記述言語:日本語

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  • 環境史をとらえる技法

    湯本 貴和, 高原 光, 村上 哲明, 瀬尾 明弘, 津村 義彦, 百原 新, 清水 勇, 川瀬 大樹, 米田 穣, 陀安 一郎, 石丸 恵利子, 兵藤 不二夫, 日下 宗一郎, 覚張 隆史, 村上 由美子, 辻野 亮, 山口 裕文, 中井 精一, 中野 孝教

    文一総合出版  2011年  ( ISBN:9784829912003

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MISC

  • ケツユクサの可塑的な性決定メカニズム:花序内の資源動態に着目して

    佐藤弘大, 宮崎祐子, 勝原光希, 邑上夏菜, 廣部宗, 兵藤不二夫, 丑丸敦

    日本生態学会大会講演要旨(Web)   68th   2021年

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  • 侵略的外来アリ類と在来アリ群集の競合機構の解明:食性解析からのアプローチ ―外来アリ類研究グループ―

    上田 昇平, 渡邊 琢斗, 池田 健一, 兵藤 不二夫

    自然保護助成基金助成成果報告書   28 ( 0 )   76 - 80   2020年

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(大学・研究所紀要)   出版者・発行元:公益財団法人 自然保護助成基金  

    <p>アルゼンチンアリ(以下,本種)は,南米を原産地とする世界的な侵略的外来種であり,国内の12都府県で定着が確認されている.本種は侵入先で在来アリ類を駆逐することで生態系機能を撹乱するとされる.本研究では,安定同位体分析を用いて本種の食性を検証し,本種と在来アリ類の競合機構を明らかにすることを目的とした.2015年,大阪府堺市では本種の侵入が確認されており,本研究グループは,環境省・地方行政と連携して本種のモニタリング調査と防除に継続して取り組んでいる.2017年10月から2018年6月にかけて本調査地から採集した本種と在来アリ8種を用いて安定同位体分析を行い,δ15N値の種間比較から,アリ類が動物質と植物質のどちらを餌として利用しているかを推定した.本種のδ15N値は,同所的に分布するアリ類の中で2番目に高く,捕食者であるオオハリアリやウロコアリ類と同程度であったこの結果は,本調査地において本種は高次消費者であり,動物類を餌として利用していることを示している.</p>

    DOI: 10.32215/pronatura.28.0_76

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  • リターの起源と降水量がリターの真菌群集と分解速度に与える影響

    舘野 隆之輔, 龍見 史恵, 兵藤 不二夫, 谷口 武士, 山中 典和, 杜 盛

    日本森林学会大会発表データベース   131 ( 0 )   829 - 829   2020年

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    記述言語:日本語   出版者・発行元:日本森林学会  

    <p>リター分解は、リターの化学性やサイトの土壌環境に加えて、分解者の真菌群集組成の影響を受けるが、真菌群集に関する知見は相対的に少ない。さらにリター分解は、他種が生育する土壌と比べて、自身が生育する土壌環境で速いことが多く(home-field advantage)、これには自身の生育環境の土壌に特異的な分解者が関与するとされるが、詳細については不明である。本研究では、中国黄土高原の乾燥傾度に沿って3か所のニセアカシア林から葉リターを採取し、それぞれのサイトにリターバッグを相互に設置し、分解速度と真菌群集組成に与えるリター起源とサイトの土壌環境(物理化学性や微生物組成など)の相対的な重要性を明らかにすることを目的とした。分解速度は、リターの起源よりサイトの影響を主に受け、また分解1年後のリターの真菌群集組成も同様に主にサイトの影響を受けていた。リターの起源により初期リターの化学性や葉圏真菌群集にも違いがみられたが、home-field advantageはみられず、乾燥傾度に沿った同一樹種間の比較では、土壌物理化学性や土壌由来の腐生菌群集の違いが分解に相対的に重要であることが示唆された。</p>

    DOI: 10.11519/jfsc.131.0_829

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  • 同位体分析が明らかにする寒帯林の植物の窒素源と生理状態の退行遷移における変化

    兵藤不二夫, 竹林佑, 眞壁明子, 眞壁明子, DAVID Wardle A., DAVID Wardle A., 木庭啓介, 木庭啓介

    日本生態学会大会講演要旨(Web)   67th   2020年

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  • 60年前の風倒木が亜高山帯無脊椎動物群集に与える影響

    鈴木智之, 角田智詞, 兵藤不二夫, 杉浦大輔, 深澤遊, 中森泰三, 金子信博

    日本生態学会大会講演要旨(Web)   67th   2020年

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  • 森林表層土壌における有機態窒素の分解性の違いと窒素無機化および窒素保持特性との関係

    安達亮太, 兵藤不二夫, 黒岩恵, 大西雄二, 福島慶太郎, 木庭啓介, 廣部宗

    日本生態学会大会講演要旨(Web)   67th   2020年

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  • 局所的環境条件がブナ若齢実生の生残と成長に及ぼす影響

    山田和弘, 赤路康朗, 宮崎祐子, 安達亮太, 谷口武士, 兵藤不二夫, 坂本圭児, 廣部宗

    日本生態学会大会講演要旨(Web)   66th   ROMBUNNO.P1‐133 (WEB ONLY)   2019年2月

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  • 安定同位体が明らかにする熱帯のアリグモにおける植物性食物の重要性

    兵藤不二夫, 山崎健史, 岩浅拓也, 市岡孝朗, 遠藤知二, 橋本佳明

    日本生態学会大会講演要旨(Web)   66th   ROMBUNNO.M02‐04 (WEB ONLY)   2019年2月

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  • 落葉広葉樹二次林における優占種コナラの成長に影響を与える環境要因

    伊藤蒼, 兵藤不二夫, 松本哲也, 赤路康朗, 宮崎祐子, 廣部宗, 西村尚之, 坂本圭児

    日本生態学会大会講演要旨(Web)   66th   ROMBUNNO.P1‐118 (WEB ONLY)   2019年2月

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  • 落葉広葉樹林の下層植生管理による土壌生物相への影響

    藤巻玲路, 兵藤不二夫, 牛川大輝, 山下多聞

    日本生態学会大会講演要旨(Web)   66th   ROMBUNNO.P2‐207 (WEB ONLY)   2019年2月

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  • 雄性両全性同株ケツユクサの花の性は資源依存的に決まるのか?

    佐藤弘大, 宮崎祐子, 勝原光希, 邑上夏菜, 廣部宗, 兵藤不二夫, 丑丸敦史

    日本生態学会大会講演要旨(Web)   66th   ROMBUNNO.P1‐152 (WEB ONLY)   2019年2月

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  • 粒径分画を用いた森林表層土壌に含まれる有機態窒素の分解性評価

    廣部宗, 冨田悟司, 浦川梨恵子, 兵藤不二夫, 柴田英昭

    日本生態学会大会講演要旨(Web)   66th   ROMBUNNO.P2‐402 (WEB ONLY)   2019年2月

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  • 樹木の機能形質の気温勾配:種内・種間パターンの共通性と相違性

    小野田 雄介, 饗庭 正寛, 黒川 紘子, 兵藤 不二夫, 市栄 智明, 中静 透

    日本森林学会大会発表データベース   130 ( 0 )   2019年

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    記述言語:日本語   出版者・発行元:日本森林学会  

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  • 魚類の産卵場及び生育場としての北部薩南海域の重要性について

    久米元, 小針統, 一宮睦雄, 小森田智大, 平井惇也, 相田真希, 兵藤不二夫, 竹田力, 重村太一, 黒田大海, 吉永尚平, 中屋慧, 鳴海敦

    日本海洋学会大会講演要旨集   2018   118   2018年9月

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  • 鹿児島湾湾口部における魚類仔魚の摂餌生態

    黒田大海, 久米元, 小針統, 竹田力, 一宮睦雄, 小森田智大, 平井惇也, 相田真希, 兵藤不二夫

    日本海洋学会大会講演要旨集   2018   125   2018年9月

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  • 鹿児島県南部の黒潮周辺海域における魚類仔魚の群集構造と摂餌生態

    吉永尚平, 久米元, 山之上香織, 田野中里佳, 小針統, 平井惇也, 相田真希, 兵藤不二夫

    日本海洋学会大会講演要旨集   2018   126   2018年9月

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  • ベトナム中部沿岸農業地域における地下水窒素汚染機構の解明

    木場 遥香, 前田 守弘, 兵藤 不二夫, 井上 大介, 近森 秀高

    日土肥講要   63 ( 0 )   14 - 14   2018年5月

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    記述言語:日本語   出版者・発行元:一般社団法人 日本土壌肥料学会  

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  • ブナ若齢実生の成長に光環境と土壌環境が与える影響

    山田 和弘, 赤路 康朗, 廣部 宗, 兵藤 不二夫, 宮崎 祐子, 坂本 圭児

    日本森林学会大会発表データベース   129 ( 0 )   2018年5月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)   出版者・発行元:日本森林学会  

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  • ブナ若齢実生の成長に光環境と土壌環境が与える影響

    山田和弘, 赤路康朗, 赤路康朗, 廣部宗, 兵藤不二夫, 宮崎祐子, 坂本圭児

    日本森林学会大会学術講演集   129th   151   2018年3月

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  • 同位体分析が解き明かすシロアリの多様な食性

    兵藤不二夫

    しろあり   ( 169 )   1‐11 - 11   2018年1月

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    記述言語:日本語   出版者・発行元:日本しろあり対策協会  

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  • 冷温帯林の二次遷移に伴う地上部‐地下部の生態特性とアリ群集の食性の変化

    兵藤不二夫, 田中洋, 原口岳, 舘野隆之輔, 廣部宗, 陀安一郎

    日本生態学会大会講演要旨(Web)   65th   ROMBUNNO.D02‐07 (WEB ONLY)   2018年

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  • 枯死木を利用する生物群集が森林生態系食物網に与える影響:50年前の風倒地を例に

    鈴木智之, 角田智詞, 杉浦大輔, 兵藤不二夫, 深澤遊, 中森泰三, 金子信博

    日本生態学会大会講演要旨(Web)   65th   ROMBUNNO.T10‐5 (WEB ONLY)   2018年

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  • 安定同位体比等を用いたベトナム中部沿岸農業地域における地下水窒素汚染機構の解明

    前田守弘, 木場遥香, 兵藤不二夫, 近森秀高, 井上大介

    日本水環境学会シンポジウム講演集   20th   219‐220   2017年9月

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  • 堆積物中の花粉組成から周辺植生を復元できるか?:REVEALSモデルを用いた北海道4湖沼における定量的な植生復元の試み

    佐々木尚子, 高原光, 杉田真哉, 林竜馬, 兵藤不二夫, 加三千宣, 占部城太郎

    日本花粉学会大会講演要旨集   58th   79   2017年9月

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  • ベトナム中部沿岸農業地域における地下水窒素汚染機構の解明

    木場遥香, 前田守弘, 兵藤不二夫, 井上大介, 近森秀高

    日本土壌肥料学会講演要旨集   63   14   2017年9月

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  • 木登りカタツムリはなぜ木に登る?~樹上生活性が進化した適応的意義~

    佐伯いく代, 丹羽慈, 長田典之, 兵藤不二夫, 太田民久, 大石善隆, 日浦勉

    日本貝類学会大会研究発表要旨集   2017   23   2017年4月

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  • 安定同位体を用いて昆虫の食性を調べる (特集 安定同位体を用いた昆虫の食性解析)

    兵藤 不二夫

    昆虫と自然   52 ( 2 )   2 - 6,図巻頭1p   2017年2月

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    記述言語:日本語   出版者・発行元:ニューサイエンス社  

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  • 森林下の埋没腐植土層における有機物続生成作用の特性

    安達 亮太, 保原 達, 金子 命, 平舘 俊太郎, 和穎 朗太, 兵藤 不二夫, 中谷 暢丈

    日本森林学会大会発表データベース   128 ( 0 )   2017年

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    記述言語:日本語   出版者・発行元:日本森林学会  

    &lt;p&gt;火山灰土壌の地下部に存在する埋没腐植土層は、植物炭化物を含む黒色土層とされるが、未だ不明点が多い。一般に土壌の黒色は植物炭化物等に含まれる縮合芳香環量と関係しているとされるが、黒色土層である埋没腐植土層の炭素濃度は概ね10%以下であり、埋没腐植土層の形成には炭素以外の元素や微生物体の寄与も考えられる。また、埋没腐植土層は表層と環境が異なり、そこでの生成物も異なる可能性がある。これらを検証するため、本研究では森林の表層土と埋没腐植土における化学特性と微生物群集構造の比較を行った。さらに、土壌に有機物(ミズナラ葉またはグルコース)を添加して培養し、有機物特性の変化を追った。そして、これら土壌の有機物構造及び元素組成の解析を行うこととした。その結果、微生物量は表層土に比べて埋没腐植土の方が低かった。従って、埋没腐植土層は微生物が生存困難な環境であると考えられる。全炭素濃度は埋没腐植土で7%程であり、概ね表層と遜色ない値を示した。これより、埋没腐植土層は表層と同程度に炭素を蓄積しうることが考えられる。発表では、有機物構造と元素組成及び群集構造などの解析結果も加えて議論する。&lt;/p&gt;

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  • ヒノキ人工林の斜面に沿った土壌の窒素無機化特性と有機態窒素存在形態

    廣部 宗, 兵藤 不二夫, 磯部 一夫, 嶋 一徹

    日本森林学会大会発表データベース   128 ( 0 )   2017年

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    記述言語:日本語   出版者・発行元:日本森林学会  

    &lt;p&gt;土壌において粒子状有機物に含まれる窒素は微生物が利用しやすく,鉱物−有機物複合体(MAOM)に含まれる窒素は利用しにくいとされる。本研究ではヒノキ人工林内の同一斜面に沿った窒素無機化特性の違いと土壌中の高分子有機態窒素の存在形態の関係を明らかにすることを目的とした。調査地は岡山県津山市のヒノキ人工林であり,斜距離約90mの斜面を対象に25か所で鉱質土層表層を採取した。純窒素無機化特性,総窒素無機化特性および粒径分画による有機態窒素存在形態の評価(53µm未満をMAOM,53µm以上を粒子状有機物・砂粒子)などを行った。純窒素無機化速度,純硝化速度および総硝化速度は斜面の上部で値が低く,MAOM窒素量(g-N/kg soil)および単位シルト・粘土重量あたりのMAOM窒素量(g-N/kg silt+clay)も斜面の上部で低かった。また,添加したアンモニア態窒素は単位シルト・粘土重量あたりのMAOM窒素量が高いとMAOMへの取り込み割合が低下した。これらから,斜面に沿った窒素無機化特性の違いにMAOMへの非生物的な窒素取り込みの違いも影響していることが示唆された。&lt;/p&gt;

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  • Effects of tropical forest remnants on the assemblage of parasitoid wasps in the surrounding areas in Borneo

    Meleng, Paulus, Itioka, Takao, Yamashita, Satoshi, Mohammad, Fatimah, Ali, Mohammas Nafri, Hossman, Mohamad Yazid, Sakai, Shoko, Takano, K. Takenaka, Hyodo, Fujio, Takematsu, Yoko, Ito, Masato, Maeto, Kaoru

    The symposium "Frontier in tropical forest research: progress in joint projects between the Forest Department Sarawak and the Japan Research Consortium for Tropical Forests in Sarawak"   169 - 174   2016年6月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

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    その他リンク: http://orcid.org/0000-0001-8803-0252

  • 木登りカタツムリが木に登らないとどうなるのか?

    佐伯いく代, 丹羽慈, 長田典之, 兵藤不二夫, 太田民久, 大石善隆, 日浦勉

    日本生態学会大会講演要旨(Web)   63th   G1‐12 (WEB ONLY)   2016年

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  • 安定同位体を用いた餌資源・食物網調査法

    土居 秀幸, 兵藤 不二夫, 石川 尚人

    1 - 164   2016年

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(商業誌、新聞、ウェブメディア)  

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  • 木の上のカタツムリを観察してみよう

    佐伯いく代, 丹羽慈, 長田典之, 兵藤不二夫, 太田民久, 日高周, 日浦勉

    日本貝類学会大会研究発表要旨集   2015   23   2015年5月

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  • 1-1-17 PTFEトラップおよびデバルダ合金を用いた化学形態別窒素安定同位体分析の適用条件(1-1 物質循環・動態,2015年度京都大会)

    木場 遥香, 前田 守弘, 兵藤 不二夫, Hoang Ngoc Tuong Van

    日本土壌肥料学会講演要旨集   61 ( 0 )   2015年

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    記述言語:日本語   出版者・発行元:一般社団法人日本土壌肥料学会  

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  • サッポロマイマイはなぜ木に登るのか?

    佐伯いく代, 丹羽慈, 長田典之, 兵藤不二夫, 日高周, 太田民久, 日浦勉

    日本生態学会大会講演要旨(Web)   62nd   PB2-103 (WEB ONLY)   2015年

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  • 近過去における湖沼の環境変動を評価するための地球化学的手法の検討

    大元 皓平, 千葉 仁, 兵藤 不二夫

    日本地球化学会年会要旨集   59 ( 0 )   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人日本地球化学会  

    本研究では,湖沼やその集水域においての過去100年における環境変遷を地球化学的に評価する手法の開発を目的とし,北海道の羅臼湖・阿寒湖・ニセコ大沼・渡島大沼、富山県のみくりが池,長野県の木崎湖,琵琶湖の計7湖沼の湖底堆積物コアサンプルの各種元素濃度を深度(年代)ごとに誘導結合型プラズマ質量分析計(ICP-MS)で測定した。また,湖沼堆積物の起源を推定することを目的として,堆積物中のSr同位体比を表面電離型質量分析計(TIMS)で測定した。その結果,琵琶湖・阿寒湖ではP( 最上部で共に > 1000ppm ),As( 最上部で共に > 100ppm )の濃度増加が確認され,湖底環境の嫌気化並びに湖水の富栄養化の影響が示唆された。また,Sr同位体比とSr濃度データから,ニセコ大沼ではSr同位体比の異なる二成分の混合が示唆されたが,他の湖沼においてはSr同位体比の異なる複数の成分は明確に区別されなかった。

    DOI: 10.14862/geochemproc.59.0.219.0

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  • 1-15 牛舎由来のアンモニア揮散が隣接圃場におよぼす影響 : 笠岡湾干拓地における一事例(1.物質循環・動態,2012年度鳥取大会)

    浅野 裕一, 前田 守弘, 兵藤 不二夫, 中島 泰弘, 藤原 拓, 永禮 英明, 赤尾 聡史

    日本土壌肥料学会講演要旨集   58 ( 0 )   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人日本土壌肥料学会  

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  • 1-45 農地排水を対象とした形態別窒素安定同位体比分析手法の検討(1.物質循環・動態)

    浅野 裕一, 前田 守弘, 兵藤 不二夫, 中島 泰弘, 藤原 拓, 永禮 英明, 赤尾 聡史

    日本土壌肥料学会講演要旨集   57 ( 0 )   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人日本土壌肥料学会  

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  • Carbon and nitrogen stable isotope analysis of dietary differences among the Jomon population in Japan. 査読

    Kusaka Soichiro, Hyodo Fujio, Yumoto Takakazu, Nakatsukasa Masato

    AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY   149   2010年

  • 1-30 笠岡湾干拓地内における水質汚染の現状と安定同位体比による汚染源の推定(1.物質循環・動態,2010年度北海道大会)

    浅野 裕一, 前田 守弘, 兵藤 不二夫, 中島 泰弘, 藤原 拓, 永禮 英明, 赤尾 聡史

    日本土壌肥料学会講演要旨集   56 ( 0 )   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人日本土壌肥料学会  

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  • Nitrogen-stable isotopic signatures of basal food items, primary consumers and omnivores in rivers with different levels of human impact (Ecological Research DOI: 10.1007/s11284-008-0489-x)

    Ayato Kohzu, Ichiro Tayasu, Chikage Yoshimizu, Atsushi Maruyama, Yukihiro Kohmatsu, Fujio Hyodo, Yukio Onoda, Akitake Igeta, Kiyoshi Matsui, Takanori Nakano, Eitaro Wada, Toshi Nagata, Yasuhiro Takemon

    Ecological Research   24 ( 1 )   137   2009年1月

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  • 大気圏核実験由来放射性炭素14を用いた生態学 (特集 生物の年代測定・年齢査定) -- (放射性炭素同位体を用いた年代測定)

    陀安 一郎, 兵藤 不二夫, 石川 尚人

    遺伝   62 ( 6 )   90 - 94   2008年11月

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    記述言語:日本語   出版者・発行元:エヌ・ティー・エス  

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  • 土壌食物網における食物の腐植化に伴う15Nの濃縮:15Nと食物年齢の関係

    兵藤不二夫, 陀安一郎, Souleymane KONATE, Jerome Ebagnerie TONDOH, Patrick LAVELLE, 和田英太郎

    日本生態学会第55回大会   2008年

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  • 食物源の年齢からみたシロアリの食性群の特徴

    兵藤 不二夫, 陀安 一郎, 和田 英太郎

    日本生態学会大会講演要旨集   52 ( 0 )   581 - 581   2005年

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    出版者・発行元:日本生態学会  

    陸上熱帯生態系において、シロアリ群集は落葉・枯死木から土壌有機物にわたる様々な分解過程の有機物を利用することで分解者として重要な役割を果たしている。様々な陸上熱帯生態系におけるシロアリ機能群を評価する一つの指標として、安定炭素・窒素同位体(δ&lt;sup&gt;13&lt;/sup&gt;C・δ&lt;sup&gt;15&lt;/sup&gt;N)が用いられてきた。これらの指標はある時間断面における生産者から始まる食物連鎖での消費者の位置づけを表している。しかし、実際の食物連鎖、特に腐植食物連鎖には生産者が有機物を生産してから消費者によって利用されるまでのタイムラグとして表される時間軸が存在し、消費者が利用する有機物は様々な年齢(古さ)を持つ。&lt;br&gt;本研究ではこの時間軸の指標として、冷戦時の核実験によって生成した放射性炭素同位体(Δ&lt;sup&gt;14&lt;/sup&gt;C)を用いて、シロアリ群集の食物源の年齢の特徴を明らかにすることを目的とした。1998年及び2004年にタイ・サケラート環境研究所の乾燥常緑林において、材木食、落葉食、土壌食の食性を持つシロアリ4種を採集し、そのδ&lt;sup&gt;13&lt;/sup&gt;C・δ&lt;sup&gt;15&lt;/sup&gt;N及びΔ&lt;sup&gt;14&lt;/sup&gt;Cの値を測定した。1998年2004年のサンプル共に土壌食性シロアリ2種は材木食・落葉食性シロアリに比べ高いδ&lt;sup&gt;15&lt;/sup&gt;N値を示した。Δ&lt;sup&gt;14&lt;/sup&gt;C値は同種内では1998年より2004年のサンプルで低い値を示し、大気中の&lt;sup&gt;14&lt;/sup&gt;C O&lt;sub&gt;2&lt;/sub&gt;の1963年以降の減少を反映していると考えられた。別種間では材木食性シロアリのほうが、土壌食性シロアリよりも高いΔ&lt;sup&gt;14&lt;/sup&gt;C値を示し、その食物源の平均年齢は材木食性シロアリで12から18年、土壌食性シロアリで7から12年、落葉食性シロアリで約8年であることが推定された。また、これらの食物源の年齢について、当調査地における土壌有機態炭素の回転時間との関連で考察を行った。

    DOI: 10.14848/esj.ESJ52.0.581.0

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  • しろかき期の濁水流出による琵琶湖への生元素負荷

    山田 佳裕, 井桁 明丈, 中島 沙知, 三戸 勇吾, 小笠原 貴子, 和田 彩香, 大野 智彦, 上田 篤史, 兵藤 不二夫, 谷内 茂雄, 陀安 一郎, 福原 昭一, 田中 拓弥, 和田 英太郎

    日本陸水学会 講演要旨集   69 ( 0 )   187 - 187   2005年

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    出版者・発行元:日本陸水学会  

    水田からの排水が琵琶湖に与える影響を評価することを目的に、圃場単位において代掻き期の粗放的水管理を再現して、水田から排出される懸濁態粒子(SS)、全窒素、全リンの量を明らかにした。水深の深い水田での強制落水時に各々最大値が得られた。この結果を、東近江地域(近江八幡_から_彦根)の水田141km&lt;sup&gt;2&lt;/sup&gt;に適用すると、すべての水田で水深を深くして強制落水を行った場合、この地域から琵琶湖北湖への全窒素と全リンの負荷率はそれぞれ約2%、約9%になると見積もられた。粗放的水管理の常態化は特にリンの琵琶湖への大きな負荷源となりうることが示された。

    DOI: 10.14903/jslim.69.0.187.0

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  • 施設9 サルの臓器間の炭素・窒素同位対比の変動(X.共同利用研究 2.共同利用研究成果)

    和田 英太郎, 田中 洋之, 兵藤 不二夫

    霊長類研究所年報   34 ( 34 )   153 - 153   2004年9月

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    記述言語:日本語   出版者・発行元:京都大学霊長類研究所  

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  • 物質循環と水資源-水系を中心として

    和田 英太郎, 陀安 一郎, 兵藤 不二夫

    エネルギー・資源   24 ( 1 )   27 - 33   2003年1月

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    記述言語:日本語   出版者・発行元:エネルギー・資源学会  

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  • キノコシロアリ亜科におけるキノコ栽培の役割とその進化

    兵藤 不二夫, 陀安 一郎, 井上 徹志, 前川 清人, 三浦 徹, 竹松 葉子, 松本 忠夫, 東 順一, 安部 琢哉

    日本生態学会大会講演要旨集   50 ( 0 )   250 - 250   2003年

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    記述言語:日本語   出版者・発行元:日本生態学会  

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  • 安定同位体を用いたシロアリとミミズの食性と機能の比較について

    陀安 一郎, 兵藤 不二夫, Konate Souleymane, Tondoh Jerome E, Lavelle Patrick

    日本生態学会大会講演要旨集   50 ( 0 )   221 - 221   2003年

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    記述言語:日本語   出版者・発行元:日本生態学会  

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  • Termites in a dry evergreen forest in Thailand: species diversity, abundance and ecosystem function.

    Hyodo, F, I. Tayasu, T. Inoue, Y. Takematsu, A. Fujita, A. Yamada, T. Kumai, N. Kirtibutr, C. Klangkaew, A. Sugimoto, T. Abe

    An integrated study on biodiversity conservation under global change and bioinventry management system. Kyoto University   186 - 198   2002年

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    記述言語:英語  

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  • B110 タイのDEFおよびDDFにおけるシロアリの種多様性とfunctional group組成(形態学・組織学,発生学・遺伝学,生活史・分布)

    竹松 葉子, 阿部 琢哉, 兵藤 不二夫, 杉本 敦子

    日本応用動物昆虫学会大会講演要旨   ( 44 )   2000年3月

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    記述言語:日本語   出版者・発行元:日本応用動物昆虫学会  

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▼全件表示

共同研究・競争的資金等の研究

  • ミミズの土壌肥沃度改善機能の活用に向けてー圃場実証と機能の定量化ー

    研究課題/領域番号:21H02335  2021年04月 - 2026年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    金田 哲, 池田 紘士, 米村 正一郎, 兵藤 不二夫, 舟山 健, 和穎 朗太, 伊藤 通浩, 上野 秀人

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    配分額:17290000円 ( 直接経費:13300000円 、 間接経費:3990000円 )

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  • 鳥類標本の羽から探る生態と種分化

    研究課題/領域番号:21H00622  2021年04月 - 2026年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    武山 智博, 小高 信彦, 水田 拓, 岩見 恭子, 富田 直樹, 兵藤 不二夫

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    配分額:17160000円 ( 直接経費:13200000円 、 間接経費:3960000円 )

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  • 斜面地形に沿った立地条件の違いに土壌微生物群集の機能や多様性が果たす役割の解明

    研究課題/領域番号:21H02235  2021年04月 - 2025年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    舘野 隆之輔, 徳地 直子, 廣部 宗, 兵藤 不二夫, 磯部 一夫

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    配分額:17160000円 ( 直接経費:13200000円 、 間接経費:3960000円 )

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  • 流域水・物質輸送に伴う藻場変遷過程の解明:生態系サービスの定量化と活用に向けて

    研究課題/領域番号:21H03650  2021年04月 - 2024年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    齋藤 光代, 濱田 麻友子, 兵藤 不二夫, 小野寺 真一, 作野 裕司

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    配分額:17290000円 ( 直接経費:13300000円 、 間接経費:3990000円 )

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  • アリグモは,なぜ植食者へと食性を転換したのか

    研究課題/領域番号:21K06310  2021年04月 - 2024年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    橋本 佳明, 市岡 孝朗, 兵藤 不二夫, 山崎 健史

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    配分額:4290000円 ( 直接経費:3300000円 、 間接経費:990000円 )

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  • 立地条件がトビムシ群集の生態系機能の温暖化応答に与える影響

    研究課題/領域番号:19K06126  2019年04月 - 2022年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    菱 拓雄, 兵藤 不二夫

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    配分額:4420000円 ( 直接経費:3400000円 、 間接経費:1020000円 )

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  • アリグモの種多様性を増大させるアリ擬態効果の解明

    研究課題/領域番号:18K06386  2018年04月 - 2021年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    橋本 佳明, 市岡 孝朗, 遠藤 知二, 兵藤 不二夫, 山崎 健史

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    配分額:4290000円 ( 直接経費:3300000円 、 間接経費:990000円 )

    熱帯で特に高い種多様性を有するハエトリグモ科アリグモ属では,各種が特定のアリ種に外見をそっくりに似せる特異なアリ擬態が見られる.我々は,この特異なアリ擬態が,擬態モデルのアリ種からの攻撃を回避し,そのなわばり内を生息や採餌場所として利用するための擬態ではないかと考えた.本研究の目的は,この仮説を検証し,アリグモがアリのなわばり内を生息場所とすることが,アリグモの生殖隔離機構として種分化を促進している可能性を検証する足がかりとすることである.本年度は,まず,ボルネオ島ランビルで,アリ類とアリグモ類で,擬態形態のマッチングの組み合わせの違いよる両者の攻撃行動や回避行動の行動生態学解析を行った.実験材料として,ツムギアリとツムギアリ擬態アリグモやトゲアリ擬態アリグモ,さらに,非擬態のハエトリグモを用い,59例の行動観察実験を動画に記録できた.その詳細な解析は,現在進行中であるが,1)アリグモが擬態モデルとしているアリ種とそうでないアリ種を認識して,回避行動を明確に変えていること,2)一方,アリ種でも,自分に擬態しているアリグモ種には積極的な攻撃行動を見せず,別のアリ種に擬態しているアリグモや非擬態のハエトリグモには,すぐに攻撃を加えることが確認できた.これらの結果は,これまで外敵から身を守るための適応現象と考えられてきた擬態に,世界で初めて,擬態モデルからの攻撃回避の効果と意味があることを実際のデータで示したものであり,我々の仮説が正しいことを支持するものである.
    さらに,1)アリグモが擬態モデルのアリが作るテリトリー内を採餌場所として利用しているのかを検証するための安定同位体分析用サンプルと,2)アリグモの擬態モデル選択が,その種分化を促進しているのかを,種分岐パターンと擬態モデル選択の合致よって検証するための系統解析用DNAサンプルの収集も実施した.

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  • 「形質アプローチ」でせまる森林の植物―土壌フィードバック

    研究課題/領域番号:17H03736  2017年04月 - 2021年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    黒川 紘子, 深澤 遊, 飯田 佳子, 兵藤 不二夫, 直江 将司, 瀧本 岳

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    配分額:17550000円 ( 直接経費:13500000円 、 間接経費:4050000円 )

    本研究では、樹木群集形成や多種共存機構の包括的理解のため、形質アプローチにより樹木群集における植物-土壌フィードバックの役割を検証する。本年度は、動態、機能形質データベースの充実・再整理のため、2018年5および9月に調査区内の毎木調査を行った。また、機能形質データベースに実生の形質情報を追加するため、6、7月に1年生以上の実生106個体(33種)の採取を行い、物理形質の測定を行った。これにより、実生、稚樹、成木の葉の機能形質の一部が揃い、群集レベルで成長段階間の比較を行ったところ、LMAや葉の強度は成木の値が最も高く、ついで稚樹、実生の順に低くなっていったが、個葉サイズは実生が一番小さいものの、成木と稚樹は大きく変わらないことなどが明らかとなった。さらに、実生の根を59個体(22種)から採取し、菌根菌、病原菌測定用に保管した。土壌特性データベースの新規構築のため、前年度の7-9月に1.2haプロット内の10m x 10m格子点(計143点)で採取し、保管してあった土壌試料の分析を開始した。現在までに、土壌含水率、bulk density, 土壌pH, アンモニウム態窒素、硝酸態窒素、無機化速度、硝化速度、PLFA法による微生物量・組成の測定が終了しており、地上部の葉の炭素やタンニン含量が多いと、土壌の菌類やバクテリアが増える可能性があることが明らかとなった。また、前年度の12月に、土壌試料を採取した場所と同じ場所で採取・保管してあった地表面の落葉試料(新規落葉と1年以上前の落葉)を樹種ごとに仕分け、現在乾燥重量を測定中である。これらの試料を採取した場所で、光、温度環境の通年測定も開始した。来年度以降も動態、機能形質、土壌、環境データベースの拡充を継続し、土壌特性の決定要因解析などを行う予定である。

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  • 同位体から昆虫の機能形質を評価する

    研究課題/領域番号:17H01912  2017年04月 - 2021年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    兵藤 不二夫, 菱 拓雄, 黒川 紘子, 岸本 圭子

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    配分額:16900000円 ( 直接経費:13000000円 、 間接経費:3900000円 )

    地球規模で生じている生物の種構成の変化が,生態系機能に及ぼす影響を明らかにすることは環境学の重要な課題である.現在,植物群集の種ごとの機能形質をもとに,その生態系機能を評価する研究が広く行われている.一方,多様な表現型を持つ昆虫など動物については,共通の機能形質を測定することが困難なため,そのような研究はほとんどない.本研究では,動物の食性を反映する同位体を用いて,昆虫の生態系機能に関連する形質を評価することを目的としている。本年度はまず調査方法の確立を行い、その後、当初予定していたモニタリング1000の3サイト(半田山(岡山県)、椎葉(宮崎県)、小佐渡(新潟県))において6月と9月の2度にわたりアリ類、トビムシ類、糞虫類や土壌有機物(リターと土壌)の採集を行った。昆虫試料については、個体数の計測や同定、同位体分析用試料の作成を行った。土壌試料については栄養塩の測定等、土壌特性の評価を行った。その結果、これら3地点での昆虫群集組成の違いや調査地ごとの特性が把握できた。昆虫試料の一部については連続フロー型同位体比質量分析計を用いて炭素、窒素同位体分析を行った。また、放射性炭素濃度については、封管法により昆虫試料から二酸化炭素を生成、グラファイトを作成し、加速器質量分析計によって放射性炭素分析を行った。また、一部の昆虫については形態計測を行い、外部形態に基づく形質評価も行った。現在、これら得られたデータの解析中である。

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  • 環境保全型農法がミミズの土壌肥沃度改善機能に及ぼす効果

    研究課題/領域番号:16H05058  2016年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    金田 哲, 池田 紘士, 小松崎 将一, 兵藤 不二夫, 舟山 健, 上野 秀人

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    配分額:17030000円 ( 直接経費:13100000円 、 間接経費:3930000円 )

    ミミズは団粒形成を促進し、養分循環を促進するため、持続的農業生産を行ううえで重要な生物群である。しかし、農薬散布や下草管理といった農法がミミズ群集やミミズの肥沃度改善機能に及ぼす影響は明らかになっていない。
    そこで本課題では、大きく4つのテーマで進めている。初年度からは1)ミミズの生活型区分の解明、2)農法がミミズ群集に及ぼす影響の解明、3)ミミズの機能の解明及び団粒形成量との関係の解明の3つのテーマを行い、最終年度に4)環境保全型農法によるミミズの土壌肥沃度改善効果の推定を行う予定である。1)ミミズの生活型区分の解明では、つくば市、苫小牧市、福島市の3ヶ所でサンプルを採取した。分析には1ヶ所につき同一種で3個体が最低必要となるが、今年の調査により、新たに2種の分析結果を得ることができた。またそれぞれの採取地でこれまでに採取していた種を採取出来た。今後、採取地毎の安定同位体比を比較し、場所により餌資源が変化しないかを評価する。2)農法がミミズ群集に及ぼす影響の解明に関する研究では、カバークロップがミミズ群集に及ぼす影響を調べるため、秋田県の農家と茨城大学で調査を行った。ミミズ幼体の種名を調べるサンプルは茨城大学で採取した。秋田県の調査は本年度で終了し、調査の結果カバークロップによるミミズ生息密度増加の効果は認められなかった。一方で低土壌pHにより生息密度が低下する傾向が検出できた。欧米では低pHによりミミズの生息密度が低下することが知られており、今後はpHの影響も評価していく必要がある。3)ミミズの機能の解明及び団粒形成量との関係を解明する研究では、団粒形成量と窒素無機化速度の関係を調べ、団粒形成量が増加するとともに窒素無機化速度が増加することを明らかにした。また、団粒形成量と養分溶脱量の関係を評価する実験系を検討し、実験準備を整えた。

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  • 熱帯雨林の食物網の安定性:昆虫標本の放射性炭素・アミノ酸同位体分析による解明

    研究課題/領域番号:16K14811  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 挑戦的萌芽研究  挑戦的萌芽研究

    兵藤 不二夫, 陀安 一郎, 市岡 孝朗

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    配分額:3640000円 ( 直接経費:2800000円 、 間接経費:840000円 )

    熱帯雨林は地球上で最も生物多様性の高い生態系の一つであり、その食物網は安定であると古くから考えられてきたが、その種数の多さや住み場所の多様性など調査の困難さから、実証的な研究はほとんどなかった。そこで、炭素・窒素安定同位体、放射性炭素同位体、アミノ酸窒素同位体を用いて、熱帯雨林の代表的な動物であるハチ目の食性を解析した。その結果、過去7年間に明瞭な食性や食物網構造の変化は見られず、従来指摘されている熱帯雨林の食物網の安定性を支持した。

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  • 同位体分析から食物連鎖の源流を探る:西部北太平洋生態系保全指標の開発に向けて

    研究課題/領域番号:16H02947  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    相田 真希, 田所 和明, 小針 統, 兵藤 不二夫, 石井 励一郎, 山口 篤, 山口 篤

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    配分額:18200000円 ( 直接経費:14000000円 、 間接経費:4200000円 )

    北太平洋亜寒帯西部~熱帯海域、チャクチ海に至る動物プランクトンの炭素・窒素安定同位体比について統計的に解析を行った。その結果、食物網の構造や構成する生物が異なっても、海域に関わらず食物連鎖とN/C同位体比には統一的な規則性があることが確認された。黒潮流域のメソ動物プランクトン群集の同位体分析から、外洋域ほど再生栄養塩・窒素固定に由来するエネルギー源を利用している可能性が示唆された。また、同海域で採集した群体珪藻・群体シアノバクテリア、稚仔魚群集の同位体比から、局所的に発生する藻類は黒潮生態系の主なエネルギー供給源とはなっておらず、黒潮流域の稚仔魚の餌料源は小型カイアシ類であることが推定された。

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  • 人為撹乱影響下におけるアフリカ大型類人猿の生態学的研究

    研究課題/領域番号:16H02753  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    湯本 貴和, 古市 剛史, 橋本 千絵, 竹ノ下 祐二, 北村 俊平, 兵藤 不二夫

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    配分額:36530000円 ( 直接経費:28100000円 、 間接経費:8430000円 )

    チンパンジーが生息しているウガンダ国カリンズ森林で、森林を構成する主要な樹種について、植物の機能形質である材密度、葉面積葉重比、葉の硬さ、窒素含有量を計測した。またチンパンジーが採食する植物の葉については、新葉と旧葉を採取して、葉面積葉重比、葉の硬さ、窒素含有量を比較した。その結果、チンパンジーが好んで食べる樹種の葉は、葉の硬さが柔らかく、窒素含有量を多い傾向があり、それは材密度が小さく、葉面積/葉重比が大きい、すなわち光環境の好適な場所で成長量が大きいという生態学的な性質と関連が大きいことがわかった。このことは、チンパンジーなどの類人猿は原生林の成熟した林分よりも、むしろ人為などで撹乱を受けた二次林などで採食する時間が長いという観察と一致した。より樹上生活に適応していると考えられるオランウータンについても、マレーシア・サバ州のキナバタンガンの森林でも、同様の植物サンプリングをおこなった。まだ窒素含有量などの計測は完結していないが、葉の硬さが柔らかい、材密度が小さい、葉面積/葉重比が大きいなど、アフリカのデータと類似する傾向があることがわかった。オランウータンの場合には、明るい環境である川辺林で採食が多くみられる一方、成熟林分内では不定期に展開する新葉をもとめて、森林内をかなり広い範囲で移動している可能性がある。今後は、キナバタンガンの森林をサンプルを国内に輸入し、さらに高度は化学分析をおこなって、厳密な比較による議論をおこなう予定である。

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  • 新しい森林生態系の窒素飽和メカニズムの提案とそれに基づく脆弱性の診断

    研究課題/領域番号:15H04515  2015年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    徳地 直子, 大手 信人, 兵藤 不二夫, 木庭 啓介, 木庭 啓介, 大手 信人

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    配分額:16250000円 ( 直接経費:12500000円 、 間接経費:3750000円 )

    集水域の綿製が小さい場合、濃度のばらつきが大きく、1ヘクタール以下の場合は、窒素飽和 と考えられないことが多いため、解析から除外した。河川水の硝酸態窒素濃度の分布を、窒素負荷量、植生、気象条件などからランダムフォレストを用いて、寄与の高いものを抽出した。その結 果、窒素負荷量そのものよりも、植物の生育期間に負荷される窒素が多い場所ほど窒素飽和が起こりやすいことがあきらかになった。

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  • 降雨パターンの変化にたいする中国黄土高原の半乾燥地生態系の脆弱性の評価

    研究課題/領域番号:15H05113  2015年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    舘野 隆之輔, 谷口 武士, 山中 典和, 兵藤 不二夫, 龍見 史恵, 杜 盛, 時 偉宇

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    配分額:17030000円 ( 直接経費:13100000円 、 間接経費:3930000円 )

    今後、地球規模で進行すると考えられる降水の変動に対して、半乾燥地の生態系がどのように変化するのかを明らかにすることを目的に、土壌養分動態とそれを担う土壌微生物に着目して研究を行った。本研究では、中国黄土高原の乾燥限界周辺の森林において、降水量の傾度に沿った調査区での野外調査に加えて、野外での降雨操作実験、野外における土壌交換培養実験、実験室における水分操作培養実験など様々なスケールでの野外・室内操作実験を行うことにより、半乾燥地生態系の土壌養分動態と土壌微生物群集が、降水量や土壌水分の短期的・長期的な変化に対してどのように変化するかを明らかにした。

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  • 安定同位体分析とIn vitroによる捕食寄生性双翅類の寄主選好性の考察

    研究課題/領域番号:26440220  2014年04月 - 2017年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    舘 卓司, 中村 達, 兵藤 不二夫

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    配分額:4940000円 ( 直接経費:3800000円 、 間接経費:1140000円 )

    捕食寄生性双翅類の成虫の炭素・窒素安定同位体分析や幼虫のIn vitroにおける室内実験によって,ヤドリバエ科幼虫の寄主に関する情報を質・量的に考察した.野外における成虫の安定同位体分析では,腐食性,寄生性,分解者などの大きな枠組みでの従来考えられている幼虫の食性を示すことが可能となった.しかし,個体差や地理的な変異が見られ,さらに食物連鎖の栄養段階が上がるほどそれは大きくなる傾向が見られた.飼育実験では,植物(人工飼料)―植食者(寄主)―捕食者(寄生者)の生物間相互作用による同位体分別が明らかになり,寄主昆虫の体液を使ってIn vitroでの人工培地の開発にも成功した.

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  • モンゴル高分解能生態系変動予測モデルの構築と気候/人間活動変動への応答予測研究

    研究課題/領域番号:25304003  2013年04月 - 2017年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    石井 励一郎, 松岡 真如, 兵藤 不二夫

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    配分額:13130000円 ( 直接経費:10100000円 、 間接経費:3030000円 )

    モンゴル北部の常緑針葉樹林-草原移行帯において、相互の植生間の遷移と土壌の生成・消失がの相互作用の時空間スケールを野外調査・分析(放射性炭素同位体・組成分析)から調べ、植生変動モデルの定量的パラメータを取得した。現生の林木の樹齢が150年程度であり、両植生の土壌中の有機物などを行った結果、草原と森林で共通する土壌深度まで平均約600-800年経ていること、森林の最深部の65cmでは6000年近く経過していること、当該地域の植生は、数百年から千年のスケールの間に、人為的伐採、森林火災、気候変動により森林と草原が何度か入れ替わっている可能性、水平的な有機物の移動の可能性が推察された。

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  • 放射性炭素が解き明かす地下部食物網を駆動する炭素の滞留時間

    研究課題/領域番号:25840158  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業 若手研究(B)  若手研究(B)

    兵藤 不二夫

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    配分額:4420000円 ( 直接経費:3400000円 、 間接経費:1020000円 )

    本研究では、異なる気候帯に属する森林に調査地を設定し、消費者やそれを支える土壌有機物を対象に放射性炭素分析から食物年齢を測定し、どの程度の時間スケールで食物網が支えられているのかを明らかにすることを目的とした。得られた結果は栄養塩濃度や土壌呼吸速度、リン脂質濃度や組成は調査地によって大きく異なることがわかった。また、土壌の放射性炭素濃度も大きく異なっていた。しかしながら、放射性炭素濃度から求めた土壌節足動物の食物年齢については、調査地間において顕著な差は見られなかった。

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  • 持続可能な生物生産のための土壌食物網設計

    研究課題/領域番号:25281053  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    金子 信博, 中森 泰三, 日浦 勉, 小松崎 将一, 島野 智之, 兵藤 不二夫, 唐沢 重考, 岡田 浩明

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    配分額:18070000円 ( 直接経費:13900000円 、 間接経費:4170000円 )

    森林と農地において土地管理が土壌生物の食物網構造を通して生態系機能に与える影響を調べ、持続可能な土地利用を可能とする生態系管理について明らかにした。土壌動物の国内における多様性情報を整理した。森林伐採により土壌有機物の分解が進行し、土壌生態系が攪乱の影響を長期に受けることがわかった。農地では耕起よりも不耕起のほうが、窒素無機化ポテンシャルは高く、ミミズやその他の土壌動物、および微生物バイオマスが増加し、特に内生菌根菌のマーカーが増加した。土壌攪乱の減少により、微生物から大型土壌動物までの現存量がともに増加する食物網構造を維持することで、植物の生長が維持されることがわかった。

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  • 大型類人猿を含む霊長類群集と森林構造の比較研究

    研究課題/領域番号:25257407  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    湯本 貴和, 古市 剛史, 橋本 千絵, 山極 壽一, 幸島 司郎, 北村 俊平, 兵藤 不二夫, 黒川 紘子

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    配分額:40690000円 ( 直接経費:31300000円 、 間接経費:9390000円 )

    調査の対象地域であったマレーシア国サバ州のダナムバレーの政治社会情勢が改善しないため、代替地である同国サバ州キナバタンガンに調査許可を申請し、植物を採集する許可を得て、調査を行った。以上の結果、当初の目的であったゴリラ、チンパンジー、ボノボ、オランウータンの生息している調査地において、それぞれの大型類人猿の行動に関連した植生および主要植物の機能形質のデータを得ることができた。

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  • アリ-アリ擬態クモ共生系の食物連鎖構造の解明:多様性創出は生態系安定に寄与するか

    研究課題/領域番号:24570109  2012年04月 - 2015年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    橋本 佳明, 市岡 孝郎, 遠藤 知二, 兵藤 不二夫

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    配分額:5590000円 ( 直接経費:4300000円 、 間接経費:1290000円 )

    我々はアリ類とその擬態クモ類の関係に着目し, 熱帯でのアリ類の飛び抜けて高い多様性がアリ擬態現象を介して,アリ類と共存関係を有する生物群の多様性創出・維持機構のひとつになっているという仮説の検証研究に取り組んで来た.本研究では.少数のアリ種が優占する熱帯乾燥林などに調査地を広げ、「特定のアリが占有する林では特定のアリに良く似たクモだけが見つかる」という予想の検証を行うことで,アリ類を鋳型とする多様性創出機構の確証を示すとともに、炭素・窒素安定同位体分析や捕食行動実験から,アリ擬態現象がクモ類の「喰い分け」機構として多種共存や生態系の安定性に寄与していることを明らかにした.

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  • 放射性炭素および分子レベル同位体解析を用いた、炭素循環と生態系構造の関係の解明

    研究課題/領域番号:22370011  2010年 - 2012年

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    陀安 一郎, 内田 昌男, 兵藤 不二夫

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    配分額:18720000円 ( 直接経費:14400000円 、 間接経費:4320000円 )

    本研究においては、放射性炭素14の分析と、炭素・窒素安定同位体比およびアミノ酸窒素同位体比を用いて、集水域レベルの炭素循環と生態系構造の関係を研究した。△14C値の測定を行なうことによって、陸域由来の隔離された炭素と大気CO2起源の炭素が混合されて河川食物網に取り込まれていることが示された。その比率は河川内部生産と外部生産の比率に依存することが分かった。

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  • 寒帯林の遷移過程における植物の窒素源の変化

    研究課題/領域番号:22770020  2010年 - 2011年

    日本学術振興会  科学研究費助成事業 若手研究(B)  若手研究(B)

    兵藤 不二夫

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    配分額:3510000円 ( 直接経費:2700000円 、 間接経費:810000円 )

    寒帯林の遷移過程における植物の窒素源の変化を明らかにするために、スウェーデン北部において約400年と5000年の遷移系列を対象にし、その植物及び土壌窒素の窒素同位体分析を行った。その結果、2つの遷移系列において植物の窒素同位体比が有意に変化することが明らかになった。土壌の溶存有機態窒素や無機態窒素の同位体分析の結果と合わせると、この植物の窒素同位体比の変化は、植物が溶存態有機窒素やコケによる窒素固定、そして菌根菌へとその窒素源を変化させていることを反映しているものと考えられる。

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  • 生体構成有機物の年令からみた陸上生態系の食物網の構造

    研究課題/領域番号:03J09346  2003年 - 2005年

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    兵藤 不二夫

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    配分額:3700000円 ( 直接経費:3700000円 )

    二酸化炭素の形で大気中にある放射性炭素(^<14>CO_2)は宇宙線の作用による上空での生成と放射性崩壊(半減期:5730年)による消失のバランスにより、大気中ではおおよそ一定量に保たれている。しかし、^<14>Cは冷戦期の核実験によって大量に作られ、その後1963年の核実験禁止条約の締結後、急激に減少している。本研究では、その核実験によって大量に作られた^<14>Cをトレーサーとして用いて、陸上食物網の構造に時間軸を導入することを目的としている。すなわち、大気14Cは光合成によって植物に取り込まれ、その年々の減少は植物の一次生産物にも反映されている。よって、これまでの既知の大気14Cの記録と消費者の体の^<14>C含量を測定し比較することで何年前に作られた一次生産物であるをその消費者は利用しているかが明らかになる。
    従来の食物網の研究では一次生産から消費者へとつながる様々な量の物質やエネルギーの流れを対象としていたが、それらの流れには別の軸、すなわち時間軸が存在することはあまり考慮されていなかった。そこでの時間軸とは、植物が大気中の二酸化炭素を固定してから、その一次生産物が消費者によって利用されるまでの時間である。私はこの時間軸のことを食物年齢(diet age)と定義した。
    本研究では熱帯生態系の重要な分解者であるシロアリを対象にその食物年齢を上述の14C分析から推定した。その結果、シロアリの食物年齢は7年から50年という幅をもつこと、また土壌食シロアリでは7-13年、木材食シロアリでは12-18年などその食性に応じた値を持つことが明らかとなった。また熱帯雨林の主要な送粉者であるハリナシバチ、ミツバチの14C含量を測定したところ、ハリナシバチでは2-4年、ミツバチでは0年と同じ生食食物網に属する生物間でも、食物年齢が異なることが明らかとなった。

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  • キノコシロアリ亜科におけるキノコ栽培の進化

    研究課題/領域番号:00J03013  2000年 - 2001年

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    兵藤 不二夫

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    配分額:2000000円 ( 直接経費:2000000円 )

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担当授業科目

  • Laboratory in Environmental Ecology 2-1 (2021年度) 第3学期  - 木5,木6,木7,木8

  • Laboratory in Environmental Ecology 2-2 (2021年度) 第4学期  - 木5,木6,木7,木8

  • コース演習1 (2021年度) 1・2学期  - 水3

  • コース演習2 (2021年度) 3・4学期  - 水3

  • コース演習3 (2021年度) 1・2学期  - その他

  • コース演習4 (2021年度) 3・4学期  - その他

  • 卒業論文 (2021年度) 1~4学期  - その他

  • 同位体生態学 (2021年度) 前期  - 水5,水6

  • 教養生物学(環境・生態・進化) (2021年度) 第4学期  - 木1~2

  • 森林生態学演習 (2021年度) 前期  - その他

  • 森林生態学演習 (2021年度) 後期  - その他

  • 森林生態学演習 (2021年度) 後期  - その他

  • 森林生態学演習 (2021年度) 前期  - その他

  • 森林生物学 (2021年度) 後期  - その他

  • 特別研究 (2021年度) 通年  - その他

  • 環境生態学コース実験2-1 (2021年度) 第3学期  - 木5,木6,木7,木8

  • 環境生態学コース実験2-2 (2021年度) 第4学期  - 木5,木6,木7,木8

  • 生態学概論1 (2021年度) 第1学期  - 金3,金4

  • 研究科目演習1 (2021年度) 1・2学期  - その他

  • 研究科目演習2 (2021年度) 3・4学期  - その他

  • Laboratory in Environmental Ecology 2-1 (2020年度) 第3学期  - 木5,木6,木7,木8

  • Laboratory in Environmental Ecology 2-2 (2020年度) 第4学期  - 木5,木6,木7,木8

  • コース演習3 (2020年度) 1・2学期  - その他

  • コース演習4 (2020年度) 3・4学期  - その他

  • 卒業論文 (2020年度) 1~4学期  - その他

  • 同位体生態学 (2020年度) 前期  - 水5,水6

  • 教養生物学(環境・生態・進化) (2020年度) 第4学期  - 木1,木2

  • 森林生態学演習 (2020年度) 前期  - その他

  • 森林生態学演習 (2020年度) 後期  - その他

  • 森林生態学演習 (2020年度) 後期  - その他

  • 森林生態学演習 (2020年度) 前期  - その他

  • 森林生物学 (2020年度) 特別  - その他

  • 特別研究 (2020年度) 通年  - その他

  • 環境生態学コース実験2-1 (2020年度) 第3学期  - 木5,木6,木7,木8

  • 環境生態学コース実験2-2 (2020年度) 第4学期  - 木5,木6,木7,木8

  • 生態学概論1 (2020年度) 第1学期  - 金3,金4

  • 研究科目演習1 (2020年度) 1・2学期  - その他

  • 研究科目演習2 (2020年度) 3・4学期  - その他

▼全件表示