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研究者情報

マスター

アカウント（マスター）

  • 氏名

    露﨑　史朗(ツユザキ　シロウ), ツユザキ　シロウ

所属（マスター）

  • 地球環境科学研究院　統合環境科学部門　自然環境保全分野

所属（マスター）

  • 地球環境科学研究院　統合環境科学部門　自然環境保全分野

独自項目

syllabus

  • 2021, 環境保全学特論, Advanced Course in Environmental Conservation, 修士課程, 環境科学院, 生態系、環境、撹乱、遷移、保全、復元 ecosystem, environment, disturbance, succession, conservation, restoration
  • 2021, 自然環境学総論, Introduction to Natural Environmental Studies, 修士課程, 環境科学院, 生態系、環境、気候、物質循環、モデル ecosystem, environment, climate, material cycling, model
  • 2021, 統合自然環境調査法実習, Field Work in Integrated Observation, 修士課程, 環境科学院, 同定、植物種、動物種、気象 Identification, plant species, animal species, climate
  • 2021, 大学院共通授業科目（教育プログラム）：JICA開発大学院連携プログラム環境科学, Inter-Graduate School Classes(Educational Program):JICA Development Studies Program for Environmental Science, 修士課程, 大学院共通科目, 気候変動とその対策、持続可能な開発目標、生態系、生物多様性、生態系を利用した災害緩和、生態系撹乱、環境修復、湿地・湿原、里山、植生、オゾン枯渇、化学センサー、環境計測 global warming and its countermeasure, sustainable development goals, ecosystems, biodiversity, disaster reduction using ecosystem, ecological disturbance, remediation, wetland, satoyama, vegetation, ozone depletion, chemical sensor, environmental monitoring
  • 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, SDGs, sustainability, resources, energy, inequality, climate change, ecosystem, biodiversity, disaster, community
  • 2021, 環境科学総論, Introduction to Environmental Science, 修士課程, 環境科学院, SDGs, sustainability, resources, energy, inequality, climate change, ecosystem, biodiversity, disaster, community
  • 2021, General Education Seminar, General Education Seminar, 学士課程, 総合教育部, environments, natural sciences
  • 2021, General Education Seminar, General Education Seminar, 学士課程, 現代日本学プログラム課程, environments, natural sciences
  • 2021, 国際交流Ⅱ, Arts and Science Courses in English 2, 学士課程, 国際本部, environments, natural sciences
  • 2021, 一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), Freshman Seminar, 学士課程, 全学教育, 洞爺湖の環境、有珠山噴火、有珠山植生回復、海藻の生態、森林の生態

researchmap

プロフィール情報

所属

  • 北極域研究センター 陸圏研究グループ, 副グループ長

学位

  • 理学博士（北海道大学）

プロフィール情報

  • プロフィール

    自然および人為撹乱により変動している生態系において、群集多様性の維持様式およびその機構について研究している。火山・スキー場斜面・湿原等を主な調査地とし、永久調査区法を中心とした調査および解析を行い、生物-環境系相互作用による群集維持機構の解明を目指している。

  • 公開用メールアドレス

    stsuyugmail.com

  • 姓

    露崎, ツユザキ

  • 名

    史朗, シロウ

  • ID各種

    200901067241663111

対象リソース

所属

  • 北極域研究センター 陸圏研究グループ, 副グループ長

業績リスト

研究キーワード

  • 永久調査区   微地形   遷移   攪乱   生物学的侵入   実生   火山遷移   多様性   菌根菌   セーフサイト   オ-ディネーション   標高勾配   谷地坊主   播種実験   環境要因   撹乱   植生回復   永久調査   共存様式   植物群集動態   定着   一次遷移   生態系復元   実生生存   定着促進効果   ファシリテーション   植生遷移   侵入   植生動態   撹乱地   植物群集生態学   Environmental Conservation   Plant community ecology   

研究分野

  • ライフサイエンス / 生態学、環境学

経歴

  • 2010年12月 北海道大学 大学院地球環境科学研究科 教授
  • 1996年01月 - 2010年11月 北海道大学 大学院・地球環境科学研究院 助教授
  • 2003年09月 - 2004年08月 西オーストラリア大学 植物科学科 客員研究員
  • 1999年05月 - 2000年01月 ブリティッシュコロンビア大学 植物学科 客員研究員
  • 1990年04月 - 1990年07月 日本学術振興会 特別研究員

学歴

  • 1987年04月 - 1990年03月   北海道大学   理学研究科   植物学専攻博士後期課程
  • 1984年04月 - 1986年03月   北海道大学   大学院環境科学研究科   環境保全学専攻修士課程

委員歴

  • 2022年10月 - 現在   北海道   土地利用審査会
  • 2018年04月 - 現在   日本生態学会   保全生態学研究誌編集委員
  • 2015年04月 - 現在   北海道   環境影響評価審議会
  • 2012年04月 - 現在   日本生態学会   自然保護専門委員
  • 2008年04月 - 現在   洞爺湖有珠山ジオパーク科学検討会   学識顧問
  • 2023年04月 - 2025年03月   北広島市 特別天然記念物野幌原始林保存活用計画検討委員会   委員長
  • 2020年04月 - 2023年03月   北広島市   特別天然記念物野幌原始林調査委員会
  • 2015年01月 - 2018年12月   日本生態学会   Associate Editor-in-Chief, Ecological Research
  • 2017年04月 - 2018年03月   環境庁   支笏洞爺国立公園有珠山周辺保全活用検討委員会
  • 2006年04月 - 2014年03月   日本植物学会   欧文誌編集員   日本植物学会
  • 2001年04月 - 2004年03月   日本生態学会   和文誌編集委員
  • 1997年04月 - 2000年03月   日本生態学会   欧文誌編集委員

受賞

  • 1994年09月 日本植物学会 奨励賞
     火山遷移初期植生回復機構の解明 
    受賞者: 露崎 史朗

論文

  • Ryoji Nakanishi, Shiro Tsuyuzaki
    Environmental Processes 2024年03月
  • Shiro Tsuyuzaki
    Earth System Science Data 2024年
  • Shiro Tsuyuzaki
    Ecological Indicators 2024年
  • Shiro Tsuyuzaki
    Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology 2023年11月02日
  • Fumiko Takeuchi, Michiru Otaki, Shiro Tsuyuzaki
    Wetlands 2023年06月
  • Shiro Tsuyuzaki
    Remote Sensing 2023年
  • Shiro Tsuyuzaki
    Mires and Peat 29 2022年11月 [査読有り]
  • Lea Végh, Shiro Tsuyuzaki
    Forest Ecology and Management 510 120106 - 120106 2022年04月
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  • Shiro Tsuyuzaki, TaeOh Kwon, Fumiko Takeuchi, Michiru Otaki, Yuki Sawada
    Canadian Journal of Forest Research 52 3 357 - 364 2022年03月 
    We measured differences in %C, %N, δ13C, and δ15N of plant functional types (PFTs) between burned and unburned ground surfaces soon after a wildfire on a north-facing slope in interior Alaska. The C and N were measured for 16 species and Sphagnum litter. δ13C differed among the PFTs and was low for trees and shrubs, suggesting that woody stems slowed C dynamics or showed low water use efficiency. δ15N concentrations suggested that the herbaceous plants depended less on the mycorrhizal associations that became weak on the burned surfaces. The shrub leaves showed the lowest δ15N of PFTs and showed higher δ15N on the burned surface, showing that N transfer from the soils to the leaves in the shrubs was slowed by the wildfire. Mosses showed the highest C/N ratio. Sphagnum litter decomposed faster on the burned surface, and %N and δ15N in the litter increased from the second to third year on both burned and unburned surfaces, while %C changed little. In conclusion, the responses to the wildfire differed among the PFTs as characterized by their C and N dynamics.
    ダウンロード
  • Shiro Tsuyuzaki
    Journal of Plant Ecology 2022年
  • 露崎 史朗, 先崎 理之, 和田 直也, 松島 肇
    保全生態学研究 26 2021 333 - 343 日本生態学会 2021年11月 [査読有り][通常論文]
     
    日本生態学会は、 2011年に石狩浜銭函地区に風発建設計画が提案されたことを受け、海岸植生の帯状構造が明瞭かつ希少であるという学術的な価値から「銭函海岸における風車建設の中止を求める意見書」を北海道および事業者に提出した。これを受け、自然保護専門委員会内に石狩海岸風車建設事業計画の中止を求める要望書アフターケア委員会（ ACC）を発足させた。しかし、風発は建設され、 2020年 2月に稼働を始めた。そこで、 ACC委員は 2020年夏期に、銭函海岸風発建設地および周辺において、植生改変状況・鳥類相に関する事後調査を実施したので、その結果をここに報告する。建設前の地上での生物調査を行わなかったため、建設後に風発周辺の地域と風発から離れた地域を比較した。概況は以下の通り。（1）改変面積 5.5 haのうちヤードが 61％を占め、作業道路法面には侵食が認められ、（2）風発は海岸線にほぼ並行して建設されたため、内陸側の低木を交えた草原帯の範囲のみが著しい影響を受け、（3）風発建設時に作られた作業道路・ヤード上には外来植物種、特にオニハマダイコンの定着が著しく、（4）鳥類は、種数・個体数が低下し群集組成が単純化していた。
  • Lea Végh, Shiro Tsuyuzaki
    International Journal of Remote Sensing 42 15 5985 - 6002 2021年08月03日 [査読有り][通常論文]
  • Rina Yonamine, Kensuke Ichihara, Shiro Tsuyuzaki, Cecile Herve, Taizo Motomura, Chikako Nagasato
    JOURNAL OF PHYCOLOGY 57 4 1356 - 1367 2021年08月 
    We examined the ultrastructure of the cell wall and immunolocalization of alginates using specific antibodies against M-rich alginates and MG blocks during rhizoid formation in fucoid zygotes, Silvetia babingtonii. The thallus region of 24-h-old zygotes had a cell wall made of three layers with different fiber distribution. In the 12-h-old zygotes, three layers in the thallus were observed before rhizoid formation, namely the inner, middle, and outer layers. During rhizoid elongation, only the inner layer was apparent close to the rhizoid tip area. Immunoelectron microscopy detected M-rich blocks of alginate on the inner half of the cell wall, irrespective of the number of layers in the thallus and rhizoid regions. The MG blocks were seen to cover a slightly wider area than M-rich alginate blocks. It was suggested that parts of M in mannuronan would be rapidly converted to G, and MG-blocks are generated. Transcriptome analysis was performed using 3 -, 10 -, and 24-h-old zygotes after fertilization to examine the relationship between gene expression and alginate synthesis over time. The expression of two mannuronan C5-epimerase homologs that convert mannuronic acid into guluronic acid in alginates was upregulated or downregulated over the course of the examination.
  • Lea Végh, Shiro Tsuyuzaki
    Ecological Research 36 2 329 - 339 2021年03月29日 [査読有り]
     
    Vegetation patch dynamics were analyzed to detect vegetation development patterns after eruptions on two sites (summit destroyed in 1977-1978, and a foothill, Konpira destroyed in 2000) on the volcano Mount Usu, in northern Japan. Aerial photos and satellite images taken in 2000, 2006, and 2014 were used to develop an imagery chronosequence of vegetation patch dynamics. Vegetation patches were identified by the Normalized Difference Vegetation Index (NDVI) for satellite images, and by the Normalized Green-Red Difference Index (NGRDI) for aerial photos. We categorized the vegetation patch types based on whether the patches overlapped (touching) or not (isolated) with the future vegetation patches and whether their area increased (growing) or decreased (shrinking). Afterwards, patch dynamics were compared between the two sites through changes in patch types, dense vegetation, and patch growth with slope degree, elevation, and time. Isolated patches were established more at the summit and showed high mortality, while at Konpira most isolated patches survived until 2006 and merged into touching patches by 2014. Moreover, the vegetation density of patches was higher at Konpira than at the summit. Patch growth was associated with patch types at both sites. However, the time was more important for the patch dynamics at the summit, and the vegetation density affected the dynamics more at Konpira. Therefore, the two sites had different vegetation patch dynamics, which were related to the characteristics of topography and eruptions. In conclusion, the imagery chronosequence proposed in this study monitored patch dynamics well, and patches developed faster at Konpira.
  • Shiro Tsuyuzaki
    Journal of Phycology 2021年
  • Shiro Tsuyuzaki
    BOTANY LETTERS 167 4 424 - 429 2020年10月 [査読有り]
     
    Hare pellets contribute greatly to the seed dispersal of a berry-producing shrub,Gaultheria miquelianaTakeda (Ericaceae), on Mount Koma, northern Japan. Numerous seeds ofG. miquelianagerminated from the hare pellets (122.2 +/- 7.3/pellet, mean +/- SE), confirming that the pellets potentially had a role in the seed dispersal. Lab-experiments confirmed that the seeds ofG. miqueliananeeded light for full germination without cold stratification. Besides, hare pellets were collected from a post-mined peatland in Sarobetsu Mire, northern Japan, whereG. miquelianawas not distributed but two berry-producing ericaceous species were distributed. No seeds germinated on the pellets collected from the Mire. These results suggested that the tight relationships between hare and berry-producing shrubs were species-specific.
  • Yuri Hoyo, Yoichiro Hoshino, Shiro Tsuyuzaki
    FOLIA GEOBOTANICA 55 3 185 - 193 2020年09月 [査読有り]
     
    Neopolyploid species have been used as model plants to elucidate the consequences of hybridization and polyploidy. Two Drosera species, D. anglica Hudson (2n = 4x = 40) and D. rotundifolia L. (2n = 2x = 20), and the hybrid D. xobovata Mert. et Koch (2n = 3x = 30), which results from their crossing, have been reported from Hokkaido Island, northern Japan. Recently, we discovered unexpected higher ploidy levels within the population of these Drosera from a post-mined peatland, in Sarobetsu mire of Hokkaido. The ploidy levels were determined by flow cytometry. Polyploids were tagged and monitored at the site for three years. The morphological characteristics of the neopolyploid leaves and flowers were determined and compared to D. anglica, D. rotundifolia and D. xobovata. Seeds collected from hexaploids were incubated in a laboratory to verify their viability. Hexaploids occurred in the field over the three years of monitoring and produced a few flowers and viable seeds; however, octoploids were extinct in the second year. The leaf shape quantified by the blade length to blade width ratio showed that the ratios of hexaploids were intermediate between D. xobovata and D. rotundifolia, suggesting that the origin of hexaploids was likely to originate from the triploid D. xobovata. Polyploidy may occur in disturbed habitats more commonly than previously thought.
  • Sharmin Shishir, Tanjinul Hoque Mollah, Shiro Tsuyuzaki, Naoya Wada
    Global Ecology and Conservation 24 2020年09月 [査読有り]
     
    Detecting the determinants of spatiotemporal distribution are important, along with the identification of drivers for the decline of the species, for ecological conservation and restoration. Here, we applied maximum entropy (Maxent)-type species-distribution modeling to investigate current and future potential distributions of an endangered canopy tree, Shorea robusta C. F. Gaertn. (Dipterocarpaceae) in Purbachal, Bangladesh. The model was constructed using 280 location records covering the entire range of S. robusta, with nine environmental variables related to climate, geography, and soil conditions included. Two scenarios [representative concentration pathways (RCPs): 4.5 and 8.5] were used to predict altered S. robusta distribution due to climate change. The precision of predicted distributions was supported sufficiently by the binomial test of omission (similar to P = 0.00) and area under the curve analysis (0.79-0.89). The current distributions were mostly determined by precipitation and soil nitrogen. Maxent modeling predicted that the suitable area for S. robusta forests will decline by 21% and 24% (Global Climate Models) and 26% and 28% (Regional Climate Models) relative to the present area according to ACCESS1-0 and CCSM4, respectively, under RCP8.5 by 2070 due to temperature rise, precipitation variability, seasonal dryness, and drought stress. These results showed that precipitation and soil nitrogen are important predictors of the current distribution and conservation of S. robusta forests. Furthermore, our results accentuate the potential negative impact of climate change, thereby encouraging further development of conservation and restoration plans for S. robusta by identifying suitable habitats in the region. (C) 2020 The Authors. Published by Elsevier B.V.
  • Shiro Tsuyuzaki, Xiaoli Zhang
    FLORA 269 2020年08月 [査読有り]
     
    Thelypteris confluens (Thunb.) C. V. Morton exhibits dimorphism between sterile and fertile fronds when fully matured. To assess the frond fertility patterns in this species, the frond size and the shape and degree of fertile fronds were measured in individuals growing in disturbed wetlands in Hokkaido, northern Japan, between late summer and early autumn in 2017 and 2018. This species often establishes on human-disturbed wetlands in boreal regions. The measured parameters were frond fertility, number of veins (NV), dry weight (DW), frond length (FL), blade length (BL), blade width (BW), frond area and blade perimeter. The Dissection Index, aspect ratio and specific frond area were calculated. The data were analyzed by generalized linear models (GLMs) and standardized major axis tests to investigate the determinants of frond fertility and the differences between the sterile and fertile fronds. All the GLMs for predicting frond fertility contained NV, FL and BL, suggesting that NV had a specific role in fertility. Compared with the use of destructive measurements, the use of nondestructive measurements in the GLMs led to slightly lower prediction accuracies. The frond sizes and shapes in relation to fertility were not strongly related to the disturbance rank scores, while the populations in highly disturbed sites showed low numbers of fertile fronds. These findings strongly suggested that the shape- and size-related variables and NV affected frond fertility differently. NV provides more precise measurements of frond maturity and population dynamics for nondestructive long-term monitoring.
  • Chikako Nagasato, Hiroki Kawamoto, Teruo Tomioka, Shiro Tsuyuzaki, Chika Kosugi, Toshiaki Kato, Taizo Motomura
    PHYCOLOGICAL RESEARCH 68 1 57 - 62 2020年01月 [査読有り][通常論文]
     
    Laminarialean plants undergo heteromorphic alternation of generations between the macroscopic diploid sporophyte and the microscopic haploid gametophyte. The generations change through the formation and release of asexual or sexual reproductive cells. It is difficult to monitor the release and diffusion of zoospores into the environment. Furthermore, even if zoospores can be detected, species identification remains difficult. This study attempted to develop a sensitive and fast identification method for laminarialean zoospores using quantitative PCR. In addition, we aimed to estimate the density of zoospores in natural seawater. Specific primers for Saccharina japonica and Undaria pinnatifida were designed and used to estimate the quantity of zoospores in seawater. DNA samples (environmental DNA) were collected from seawater once or twice each month for 2 years at the same area, and seasonal variations in the release of zoospores was monitored. The estimated maturation period based on the number of released zoospores in this study was comparable with those of the previously reported maturation periods of S. japonica and U. pinnatifida sporophytes. This supports the validity of our method in estimating zoospore release from laminarialean plants. The method will be a useful tool for ecological studies on these commercially relevant species.
  • Shiro Tsuyuzaki
    Ecological Research 34 6 813 - 820 2019年11月09日 [査読有り][通常論文]
     
    The revegetation patterns after volcanic eruptions were monitored annually on Mount Usu, northern Japan, using over 25 years to detect successional changes. The vegetation was monitored by 2 x 5 m plots from 1984 and 2008 and by 5 x 5 m plots that were enlarged from the original plots from 1994 to 2008 due to increasing vegetation height. The thick tephra from these eruptions destroyed the former vegetation in 1977 and 1978. Diversity indexes were calculated, and nonmetric multidimensional scaling (NMDS) was conducted using the vegetation data with environmental factors. The cover of dominant species was higher in the large plots probably due to the vegetative expansion. Species richness and diversity continued to increase annually for 30 years after the eruptions. Well-established plants were perennial forbs and trees and the species replacement occurred consistently. NMDS of small plot data suggested that elevation was related to the first axis, and year, litter volume and distance to the caldera rim were related to the second axis. Plot scores on the first axis suggested that deterministic factors, that is, elevation and its related factors, produced vegetation convergence but those on the second axis suggested that the vegetation change was in response to stochastic factors, such as litter accumulation and its related unmeasured factors, with year. The results indicated that the convergence or divergence was determined by the conflict between the net effects of deterministic and stochastic factors on vegetation development.
  • Michiru Otaki, Shiro Tsuyuzaki
    ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 101 2019年11月 [査読有り][通常論文]
     
    Biological litter decomposition and the litter-associated microbial organisms were monitored for three years to characterize litter decomposition in early and late successional stages. Two forests were used for the investigation: pioneer a forest dominated by birch (Betula platyphylla var. japonica) and a climax forest by oak (Quercus mongolica var. grosseserrata) in the cool-temperate region of northern Japan. Three types of litter were used: birch, oak and mixed litter. The litter decomposition was effective during the first year but 50% of the original litter remained even after three years. Carbon-to-nitrogen ratios in the litter decreased largely in the first year and became stable thereafter. The litter decomposition rates were not different among the litter types and between the forests. The temporal changes in phospholipid fatty acids (PLFAs) showed that fungal biomass reached its peak in the first year and the bacterial biomass increased steadily until the end of the experiment. The concentrations of fungal PLFAs in the litter did not differ between the litter types but were lower in the oak forest. The litter decomposition was performed mostly by fungi, in particular in the early stages, while bacterial decomposition depended on the litter types and/or the forest types. Gram-negative bacteria reached their peak of PLFAs in the second year while gram-positive bacteria PLFAs increased gradually during the three years. Therefore, the succession of microorganisms in the litter occurred from fungi to bacteria and from gram-negative bacteria to gram-positive bacteria in the two forests. Unlike in the case of coniferous or monotonic forests, the effects of forests and litter types on litter decomposition for the first year were weak. The forest types on litter decomposition appeared only for the long-term litter decomposition. The successional changes of microorganisms occurred from fungi to bacteria for long-term litter decomposition processes with increasing N concentration in the litter.
  • Mukhlish Jamal Musa Holle, Shiro Tsuyuzaki
    Acta Oecologica 93 48 - 55 2018年11月 [査読有り][通常論文]
     
    Vegetation recovery on Mount Koma, Hokkaido, Japan, has been slow after the catastrophic eruption in 1929, due to undeveloped soil and limited plant colonization. Nowadays, the seedling establishment is supported mostly by a nurse plant, Salix reinii forming shrub patches, facilitates the plant colonization. Although the effects of shrub patches should differ with patch sizes, the size effects have not been examined well. To examine the size effects, seed-sowing experiments were conducted on two common pioneer herbaceous species, Misamthus sinensis and Polygonum sachalinense, in the field. The seed germination and seedling survival were monitored by the seeds sown into S. reinii patches (0.97 m(2)-4.12 m(2) in area) for 4 months during snow-free periods. Microenvironments altered by the patches were measured. Lab-experiments were performed to characterize the seed germination and seedling growth.Larger patches decreased light intensity and temperature more and increased litter and water content. The large patches promoted the seed germination of the two species. Interspecific interactions, examined by a seed mixture experiment, showed that the interaction increased the seed germination on M. sinensis and decreased that on P. sachalinense. On the lab-experiments at three temperatures (15, 20 and 25 degrees C), M. sinensis seeds germinated more at higher temperatures and obtained higher seedlings biomass. P. sachalinense germinated the seeds more at 20 degrees C and grew faster at lower temperatures. The total biomass of the two species was reduced by shade that intercepted 50% of light intensity. The seed germination and seedling growth of these two species became higher on litter with 2 cm in depth than on no litter. Soil water supported seed germination when the seeds of these two species were mixed while the water reduced the growth of P. sachalinense seedlings. Therefore, the dry soils were suitable for their growths. In all the treatments, P. sachalinense seedlings showed higher mortalities than M. sinensis.In conclusion, the large patches facilitated more to the colonization of pioneer plants via seed germination and growth. Large patches acted as a nursery supporting the natural regeneration in the disturbed area by improving litter accumulation, maintaining soil water, reducing strong light and/or protecting from heat.
  • Sharmin Shishir, Shiro Tsuyuzaki
    ENVIRONMENTAL MONITORING AND ASSESSMENT 190 6 2018年06月 [査読有り][通常論文]
     
    Detecting fine-scale spatiotemporal land use changes is a prerequisite for understanding and predicting the effects of urbanization and its related human impacts on the ecosystem. Land use changes are frequently examined using vegetation indices (VIs), although the validation of these indices has not been conducted at a high resolution. Therefore, a hierarchical classification was constructed to obtain accurate land use types at a fine scale. The characteristics of four popular VIs were investigated prior to examining the hierarchical classification by using Purbachal New Town, Bangladesh, which exhibits ongoing urbanization. These four VIs are the normalized difference VI (NDVI), green-red VI (GRVI), enhanced VI (EVI), and two-band EVI (EVI2). The reflectance data were obtained by the IKONOS (0.8-m resolution) and WorldView-2 sensor (0.5-m resolution) in 2001 and 2015, respectively. The hierarchical classification of land use types was constructed using a decision tree (DT) utilizing all four of the examined VIs. The accuracy of the classification was evaluated using ground truth data with multiple comparisons and kappa (kappa) coefficients. The DT showed overall accuracies of 96.1 and 97.8% in 2001 and 2015, respectively, while the accuracies of the VIs were less than 91.2%. These results indicate that each VI exhibits unique advantages. In addition, the DT was the best classifier of land use types, particularly for native ecosystems represented by Shorea forests and homestead vegetation, at the fine scale. Since the conservation of these native ecosystems is of prime importance, DTs based on hierarchical classifications should be used more widely.
  • Shiro Tsuyuzaki, Go Iwahana, Kazuyuki Saito
    POLAR BIOLOGY 41 4 753 - 761 2018年04月 [査読有り][通常論文]
     
    Tundra fires are increasing in their frequencies and intensities due to global warming, which alter revegetation patterns through various pathways. To understand the effects of tundra fire and the resultant thermokarst on revegetation, vegetation and related environmental factors were compared between burned and unburned areas of Seward Peninsula, Alaska, using a total of 140 plots, 50 cm x 50 cm each. The area was burned in 2002 and surveyed in 2013. Seven vegetation types were classified by a cluster analysis and were categorized along a fire-severity gradient from none to severe fire intensity. The species richness and diversity were higher in intermediately disturbed plots. Severe fire allowed the immigration of fire-favored species (e.g., Epilobium angustifolium, Ceratodon purpureus) and decreased or did not change the species diversity, indicating that species replacement occurred within the severely burned site. Although thermokarsts (ground subsidence) broadly occurred on burned sites, due to thawing, the subsidence weakly influenced vegetation patterns. These results suggest that the fire directly altered the species composition at a landscape scale between the burned and unburned sites and it indirectly altered the plant cover and diversity through the differential modification, such as thermokarst, at a small scale within the burned site.
  • Akira S. Hirao, Mikio Watanabe, Shiro Tsuyuzaki, Ayako Shimono, Xuefeng Li, Takehiro Masuzawa, Naoya Wada
    Journal of Biogeography 44 12 2740 - 2751 2017年12月19日 [査読有り][通常論文]
     
    AimWe identified and evaluated general latitudinal trends in genetic diversity within populations of a widespread arctic-alpine plant, Dryas octopetala, to examine the applicability to this species of the dominant hypothesis that intraspecific genetic diversity is highest in the tropics and declines towards the poles.LocationThe circumpolar Arctic and northern temperate alpine ranges, with a focus on high altitude mountains at the species lowest latitudinal margin in the Japanese archipelago.MethodsWithin-population genetic diversity was assessed using genotypes determined at nine microsatellite loci (n=489), chloroplast DNA sequences (atpB-rbcL and trnV-ndhC spacers, n=181) and a nuclear gene sequence (LEAFY, n=173) of 18 populations, as well as a previously published amplified fragment length polymorphism dataset for 26 populations, across the distributional range of the species. The latitudinal pattern of intra-population genetic diversity was modelled at hemispheric scale to discriminate linear latitudinal and quadratic central-marginal trends in genetic diversity. Population genetic structure was assessed by Bayesian clustering analyses.ResultsAt hemispheric scale, we identified two interacting effects: a general latitudinal decline in genetic diversity towards the equator and a central-marginal effect, whereby genetic diversity decreases towards the margins of a species' range. This decrease was more marked in low-latitude marginal populations than in high-latitude marginal populations. Populations at the lowest latitudes in the Japanese archipelago showed the lowest level of genetic diversity but exhibited distinctive genetic variation.Main conclusionThe latitudinal decline in genetic diversity within populations of this arctic-alpine plant across its range was opposite to the commonly observed trend. A significant part of the equator-ward latitudinal decline in genetic diversity in this arctic-alpine species may be attributable to a sky island effect, which played a greater role at low latitudes.
  • 江川知花, 西村愛子, 小山明日香, 露崎史朗
    保全生態学研究 22 1 187 - 197 [日本生態学会] 保全生態学研究編集委員会 2017年05月 [査読有り][通常論文]
  • Hirata, A.K.B., Tsuyuzaki, S.
    Wetlands Ecology and Management 24 5 521 - 532 2016年 [査読有り][通常論文]
     
    The responses of seedlings to solar radiation, including ultraviolet (UV), were investigated for Rhynchospora alba, an early colonizer, and Molinia japonica, a late colonizer, in a mined peatland in northern Japan. The solar radiation and rainfall were, respectively, higher and lower in 2008 than in 2009 during the field surveys. The seedlings were transplanted to bare ground, and measurements were made of the biomass, the allocation of biomass to shoots and roots, the absorbance of ultraviolet A and ultraviolet B, and the concentrations of anthocyanin and chlorophyll. R. alba did not change its biomass in response to any solar radiation treatment in 2008 and decreased shoot biomass with low UV and decreased root biomass with shade in 2009. Additionally, M. japonica did not change its biomass in 2008 but decreased its root biomass with low UV in 2009. The chlorophyll concentration of R. alba did not change in 2008 or 2009, whereas the chlorophyll concentration of M. japonica increased with decreased solar radiation, including UV. The UV absorbance of R. alba decreased under shade and with high peat moisture. In contrast, the content of UV-absorbing substances remained unchanged in M. japonica. Therefore, R. alba, the early colonizer, adapted more to strong solar radiation by changing its shoot-root allometry and producing UV-absorbing substances, whereas M. japonica, the late colonizer, tended to respond more to peat moisture. These differing responses to solar radiation and peat moisture may explain the temporal patterns of species replacement from early to late colonizers.
  • Iwahana, G., Harada, K., Uchida, M., Tsuyuzaki, S., Saito, K., Narita, K., Kushida, K., Hinzman, L.D.
    Journal of Geophysical Research F: Earth Surface 121 9 1697 - 1715 2016年 [査読有り][通常論文]
     
    Geomorphological and thermohydrological changes to tundra, caused by a wildfire in 2002 on the central Seward Peninsula of Alaska, were investigated as a case study for understanding the response from ice-rich permafrost terrain to surface disturbance. Frozen and unfrozen soil samples were collected at burned and unburned areas, and then water isotope geochemistry and cryostratigraphy of the active layer and near-surface permafrost were analyzed to investigate past hydrological and freeze/thaw conditions and how this information could be recorded within the permafrost. The development of thermokarst subsidence due to ice wedge melting after the fire was clear from analyses of historical submeter-resolution remote sensing imagery, long-term monitoring of thermohydrological conditions within the active layer, in situ surveys of microrelief, and geochemical signals recorded in the near-surface permafrost. The resulting polygonal relief coincided with depression lines along an underground ice wedge network, and cumulative subsidence to 2013 was estimated as at least 10.1 to 12.1 cm (0.9-1.1 cm/year 11 year average). Profiles of water geochemistry in the ground indicated mixing or replenishment of older permafrost water with newer meteoric water, as a consequence of the increase in active layer thickness due to wildfire or past thaw event. Our geocryological analysis of cores suggests that permafrost could be used to reconstruct the permafrost degradation history for the study site. Distinct hydrogen and oxygen isotopic compositions above the Global Meteoric Water Line were found for water from these sites where permafrost degradation with geomorphological change and prolonged surface inundation were suggested.
  • Kwon, T.O., Tsuyuzaki, S.
    Ecological Research 31 4 557 - 567 2016年 [査読有り][通常論文]
     
    Relationships involving the transfer of nitrogen (N) among Salix reinii (willow), Larix kaempferi (larch), and mycorrhizal fungi were investigated in a ridge and hillslope on the volcano Mount Koma in northern Japan using a two-pool fungal model. This model estimated N transfer among the examined taxa by measuring changes in the stable isotope ratio of N (delta N-15). Although N content in tephra was low at both sites, it was higher on the ridge than on the hillslope, and higher in the willow patch than on bare ground or in the larch understory. The non-mycorrhizal sedge (Carex oxyandra) exhibited non-significant differences between the two sites regarding delta N-15 for N obtained from tephra. Larches developed a relationship with larch-specific Suillus mycorrhizal fungal species in the roots, and had a lower foliar delta N-15 on the hillslope than on the ridge. The larch delta N-15 increased during the growing season, while the willow delta N-15 remained stable. The dependence of larch on mycorrhizal fungi for N uptake was 3-5 % on the ridge and 56-76 % on the hillslope in autumn. Therefore, larches exhibited a flexible symbiotic relationship with mycorrhizal fungi for obtaining N. Over 45 % of the N taken up by willow plants was obtained from mycorrhizal fungi at both sites. In conclusion, willow plants promoted N deposition in tephra through the litter supply, and formed a stable relationship with mycorrhizal fungi. This enabled successful revegetation with larch plants, which exhibited flexibility in terms of N uptake (i.e., dependent on mycorrhizae or from tephra).
  • Otaki, M., Takeuchi, F., Tsuyuzaki, S.
    Journal of Mountain Science 13 9 1652 - 1662 2016年 [査読有り][通常論文]
     
    Changes in the fungal and bacterial biomass and community structure in litter after the volcanic eruptions of Mount Usu, northern Japan were investigated using a chronosequence approach, which is widely used for analyzing vegetation succession. The vegetation changed from bare ground (10 years after the eruptions) with little plant cover and poor soil to monotonic grassland dominated by Polygonum sachalinense with undeveloped soil (33 years) and then to deciduous broad-leaved forest dominated by Populus maximowiczii with diverse species composition and well-developed soil (100 years). At three chronosequential sites, we evaluated the compositions of phospholipid fatty acids (PLFAs), carbon (C) and nitrogen (N) contents and the isotope ratios of C (delta C-13) and N (delta N-15) in the litter of two dominant species, Polygonum sachalinense and Populus maximowiczii. The C/N ratio, d13C and d15N in the litter of these two species were higher in the forest than that in the bare ground and grassland. The PLFAs gradually increased from the bare ground to the forest, showing that microbial biomass increased with the development of the soil and/or vegetation. The fungi-to-bacteria ratio of PLFA was constant at 5.3 +/- 1.4 in all three sites, suggesting that fungi were predominant. A canonical correspondence analysis suggested that the PLFA composition was related to the successional ages and the developing soil properties (P < 0.05, ANOSIM). The chrono-sequential analysis effectively detected the successional changes in both microbial and plant communities.
  • Nanae Nomura, Shiro Tsuyuzaki
    Acta Oecologica 63 22 - 27 2015年02月 [査読有り][通常論文]
     
    Although seed dispersal through animal guts (endozoochory) is a process that determines plant establishment, the behaviour of carriers mean that the seeds are not always dispersed to suitable habitats for germination. The germinable seeds of Gaultheria miqueliana were stored in the pellets of a hare (Lepus timidus ainu) on Mount Koma in northern Japan. To clarify the roles of hares in seed dispersal and germination, field censuses and laboratory experiments were conducted. The field observations were conducted on pellets and seeds in four habitats (bare ground, G. miqueliana shrub patch, Salix reinii patch, and Larix kaempferi understory), and the laboratory experiments were conducted on seed germination with different light, water potential and cold stratification treatments. The laboratory experiments confirmed that seed germination began a few weeks after the sowing of seeds, independent of cold stratification, when light was sufficient and the water potential was low. The seeds did not germinate at high water potential. The pellets were gradually degraded in situ. More seeds germinated from crushed than from intact pellets. Therefore, over the long term, seeds germinated when exposed to light due to the degradation of pellets. The pellets were proportionally dispersed among the four studied habitats. More seeds sown in the field germinated more in shaded habitats, such as in the Gaultheria patch and the Larix understory, and seeds did not germinate on bare ground, where drought often occurred. Thus, the hares had two roles in the dispersal and germination of seeds: (1) the expansion of G. miqueliana populations through seed dispersal to various habitats and (2) the facilitation of delayed seed germination to avoid risks of hazards such as drought. The relationships between small mammals represented by the hare and the shrubs that produce berries are likely to be more mutually evolved than was previously thought. (C) 2015 Elsevier Masson SAS. All rights reserved.
  • Narita, K., Harada, K., Saito, K., Sawada, Y., Fukuda, M., Tsuyuzaki, S.
    Arctic, Antarctic, and Alpine Research 47 3 547 - 559 2015年 [査読有り][通常論文]
     
    The recovery of tundra vegetation and the depth of permafrost thaw were observed on the Seward Peninsula, Alaska, the site of a wildfire in 2002. The study compared the vegetation in burned and adjacent unburned tundra from 5 to 10 years post-fire. The effects of the fire on the vegetation varied between species and were spatially variable at the stand scale. The cover of evergreen shrubs, bryophytes, and lichens was still drastically decreased 5 years after the fire and had not recovered even 10 years after the fire. By contrast, the cover of graminoids, especially Eriophorum vaginatum, and of the deciduous shrub Vaccinium uliginosum increased. The depth of permafrost thaw increased, and its spatial pattern was related to vegetation structure; specifically, deeper thaw corresponded to graminoid-rich areas, and shallower thaw corresponded to shrub-rich areas. As the E. vaginatum cover increased, the thaw depth recovered to that of the unburned area, and the spatial variation had disappeared 10 years after the fire. Our results indicate that both the prefire vegetation structure and the differences in the regrowth properties between species play important roles in the early stage of tundra ecosystem recovery after wildfire. Our findings also show that the favorable growing conditions related to deeper thaw do not last long.
  • Kushida, K., Hobara, S., Tsuyuzaki, S., Kim, Y., Watanabe, M., Setiawan, Y., Harada, K., Shaver, G.R., Fukuda, M.
    International Journal of Remote Sensing 36 17 4344 - 4362 2015年 [査読有り][通常論文]
     
    The relationships among in situ spectral indices, phytomass, plant functional types, and productivity were determined through field observations of moist acidic tundra (MAT), moist non-acidic tundra (MNT), heath tundra (HT), and sedge-shrub tundra (SST) in the Arctic coastal tundra, Alaska, USA. The two-band enhanced vegetation index (EVI2) was found more useful for estimating vascular plant green phytomass, leaf carbon and nitrogen, leaf carbon and nitrogen turnover, and vascular plant net primary productivity (NPP) without root production than the normalized difference vegetation index (NDVI). Deciduous shrub green phytomass was strongly correlated with deciduous shrub index (DSI), defined as EVI2 x (R-blue + R-green - R-red)/(R-blue + R-green + R-red) (with a coefficient of determination (R-2) of 0.63). R-blue, R-green, and R-red denote the blue, green, and red bands, respectively. This is because R-blue and R-green values were higher than the Rred values for green leaves, deciduous shrub stems, lichens, and rocks compared with other ecosystem components, and EVI2 values of lichens and rocks were very low. The vascular plant NPP without root production was estimated with an R-2 of 0.67 using DSI and EVI2. Our results offer empirical evidence that a new spectral index predicts the distribution of deciduous shrub and plant production, which influences the interactions between tundra ecosystems and the atmosphere.
  • Hoyo, Y., Tsuyuzaki, S.
    Flora: Morphology, Distribution, Functional Ecology of Plants 210 60 - 65 2015年 [査読有り][通常論文]
     
    Two Drosera species, D. anglica and D. rotundifolia, are established in Sarobetsu mire, Northern Japan. D. anglica is an endangered species in Japan because of its small numbers and population sizes, whereas D. rotundifolia is widespread throughout the country. We hypothesized that the reproductive strategies of these species are closely related to the differences in their population dynamics. To test this hypothesis, we monitored the plant size; flower development; daughters, formed by dormant buds; survival; and growth of the two Drosera species in five 300 cm x 40 cm plots in a post-mined Sphagnum peatland in Sarobetsu mire from 2009 to 2011. The two Drosera species maximized their total leaf area in mid-July; all D. anglica individuals flowered at precisely the same time, but D. rotundifolia flowered two weeks after D. anglica. The dormant buds were formed in the late fall of the previous year. Both D. anglica and D. rotundifolia increased their sexual and vegetative reproduction with increasing shoot size. However, seed production was lower in D. anglica than in D. rotundifolia, and the production of daughters was more than three times higher for D. anglica than for D. rotundifolia. These results indicate that D. anglica and D. rotundifolia populations are primarily maintained by vegetative reproduction and sexual reproduction, respectively. Vegetative reproduction does not allow for long-distance migration; thus, D. anglica established in restricted habitats and was characterized by a reduced population size and endangered status. Further, these results suggest that employing very careful management strategies to protect endangered species is important, with particular focus on providing preferable habitats rather than increasing population sizes. (C) 2014 Elsevier GmbH. All rights reserved.
  • Nishimura, A., Tsuyuzaki, S.
    Folia Geobotanica 50 2 107 - 121 2015年 [査読有り][通常論文]
     
    Nitrogen addition experiments were conducted in three plant communities in a post-mined peatland and on the surrounding original Sphagnum bog in northern Japan to compare the effects of nitrogenous fertilization among the plant communities. Gradients of added nitrogen were prepared by adding nitrogen to 1 m x 1 m plots at rates of 0-36 g/m(2)/yr. These different levels of nitrogen addition were applied to four sites representing a vegetation development chronosequence: bare ground (BG), a Rhynchospora alba sedgeland (RA), a Moliniopsis japonica grassland (MJ) and the original Sphagnum bog (SS). Vegetation was monitored in each plot for three years, and the groundwater level and nitrogen concentration in peat-pore water were monitored in each plot. The nitrogen concentration in peat-pore water increased with increasing nitrogen addition on BG, but was constantly low at the vegetated sites, suggesting the occurrence of nutrient uptake by plants. Species richness decreased as a result of nitrogen addition at the SS site, where plant cover was high. The aboveground biomass of the two common grasses M. japonica and Phragmites communis was not influenced by nitrogen addition in the post-mined peatland. Grasses and sedges, which produce large underground organs, showed increased biomass as a result of nitrogen addition in the SS plot whereas Sphagnum declined. Additionally, forbs declined in the SS plot with increasing nitrogen, most likely due to competition with the increased populations of grasses. Therefore, nitrogen enrichment can promote the dominance grasses, leading to a decrease in mosses and forbs.
  • Egawa, C., Tsuyuzaki, S.
    Acta Oecologica 62 45 - 52 2015年 [査読有り][通常論文]
     
    In disturbed habitats, shade often has facilitative effects on plants by ameliorating water and thermal stresses. Facilitation by shade tends to increase as water availability decreases. At the same time, several studies have suggested that facilitation by shade is not affected by water status or collapses under extremely dry conditions. We hypothesized that traits of beneficiary plants, specifically, the flexibility in the allocation of biomass between shoots and roots, would mediate variation in the relationship between facilitation by shade and water status. To test this hypothesis, we examined the responses of two bog species to shade under various water conditions in a post-mined peatland. The seeds of Rhynchospora alba and Moliniopsis japonica were sown under three water levels (dry: 53% peat water content, wet: 77%, and control: 71%) x two shading levels (50% shaded and unshaded). The survival, biomass, and biomass allocation between the shoots and roots of the two species were monitored for two years. Shade increased the survival and biomass of both species. However, the facilitation of R. alba by shade was independent of water level, whereas the strength of the facilitative effects on M. japonica increased as water content decreased. R. alba preferentially allocated biomass to roots under dry conditions and was highly drought tolerant. M. japonica did not alter the allocation of its biomass in response to either shade or water level and was drought intolerant. Our results suggest that flexibility in biomass allocation of beneficiary plants mediates occurrence patterns of facilitation by shade along a water gradient. The facilitation of species with inflexible biomass allocation by shade through the amelioration of water stress increases as water availability decreases, whereas the facilitation of species with flexible biomass allocation is independent of water status. Such species-specific facilitation would promote the coexistence of diverse species in a community. (C) 2014 Elsevier Masson SAS. All rights reserved.
  • Hoyo, Y., Tsuyuzaki, S.
    Wetlands 34 5 943 - 953 2014年 [査読有り][通常論文]
     
    The preservation of endangered species requires clarifying habitat preferences through survival, growth and competitive ability. The determinants of habitat differentiation between the endangered species, Drosera anglica, and a widespread congener, D. rotundifolia, were compared. The effects of water level, Sphagnum mats and overstory vascular plants on Drosera distribution, recruitment and survival were monitored at a previously mined Sphagnum peatland. Seedling transplant experiments were conducted using different water levels. Seed-sowing experiments were conducted using different light intensities in three habitat-types: bare ground, Sphagnum mat and waterlogged surface. Distributions of D. anglica and D. rotundifolia were determined using survival at the seedling stage. D. anglica seedling recruitment and survival occurred more at lower water levels and/or lower plant cover, while D. rotundifolia seedlings established independent of these factors. In the greenhouse the seedlings of both species survived better at lower water levels but grew more slowly. D. anglica seedlings reduced their growth under shade more than D. rotundifolia. D. anglica showed low competitive light and nutrient ability on Sphagnum mats. Therefore, D. anglica was pushed to areas of high water levels where few competitors could establish. The habitat differentiation between D. anglica and D. rotundifolia originated from the interactions with Sphagnum mats.
  • Nishimura, A., Tsuyuzaki, S.
    Wetlands 34 1 117 - 127 2014年 [査読有り][通常論文]
     
    The recovery of plant communities is related to various environmental factors, in particular, waterlevel and chemistry, after peat mining. The changes over time after peat-mining were annually monitored from 2002 to 2007 in Sarobetsu peatland mined during 1970 and 2003, northern Japan, by using permanent plots setting up in various ages after mining. Rhynchospora alba was the earliest colonizer in the post-mined peatland, and three grasses followed. The recovery was slow when waterlevel was low, while Sphagnum papillosum, being predominant in pre-mined peatland, established well in post-mined sites with high waterlevel of which values were equivalent to post-mined site. Water chemistry was variable according to the effect of waterlevel in the post-mined peatland, while they were relatively stable in pre-mined peatland. Therefore, with large scale, merged with post-and pre-mined peatlands, water chemistry became the first determinants manipulated by waterlevel. In conclusion, high waterlevel that decreases nutrients in groundwater is a prerequisite to promote Sphagnum recovery in a post-mined peatland. Also, low pH was related to nutrient uptake by vascular plants and dilution by groundwater, and was advantageous for Sphagnum establishment. Re-establishment of vascular plants may promote the stabilization of water chemistries and facilitate revegetation towards the original Sphagnum peatland.
  • Tsuyuzaki, S., Narita, K., Sawada, Y., Kushida, K.
    Plant Ecology 215 3 327 - 337 2014年 [査読有り][通常論文]
     
    Fire severity is predicted to increase in boreal regions due to global warming. We hypothesized that these extreme events will alter regeneration patterns of black spruce (Picea mariana). To test this hypothesis, we monitored seed dispersal and seedling emergence, survival and growth for 6 years from 2005 to 2010 after the 2004 wildfire on Poker Flat, interior Alaska, using 96 1 x 1 m plots. A total of 1,300 seedlings of black spruce and three broad-leaved deciduous trees (Populus tremuloides, Betula papyrifera, and Salix spp.) were recorded. Black spruce seedlings colonized burned and unburned ground surfaces for the first 2 years after the wildfire and established on any topographical surface, while the broad-leaved trees emerged less in areas of lower elevation, slope gradient and canopy openness and only on burned surfaces. Vascular plant cover on the ground floor increased the seedling establishment of black spruce and broad-leaved trees, most likely because of seed-trap effects. Black spruce grew faster on burned surface than on unburned surfaces. However, broad-leaved trees grew faster than black spruce on burned surfaces. Black spruce regenerates even after severe wildfire when the microtopography restricts the colonization of broad-leaved trees. The regeneration trajectories are determined soon after wildfire by a combination of seed limitation for black spruce and habitat preference for broad-leaved trees.
  • Chika Egawa, Shiro Tsuyuzaki
    JOURNAL OF VEGETATION SCIENCE 24 6 1062 - 1073 2013年11月 [査読有り][通常論文]
     
    QuestionsHow does litter accumulation through succession affect secondary seed dispersal and buried seed viability and consequently control seed bank formation for small- and large-seeded species?LocationA post-mined peatland in northern Japan (45 degrees 06N, 141 degrees 42E) where the chronological sequence of plant community succession is known.MethodsThe movements of seeds after reaching the ground surface and the availability of viable seeds potentially contributing to seed bank formation at various depths were experimentally investigated for 1yr in four species that produce different-sized seeds: Drosera rotundifolia (seed mass 0.01mg), Lobelia sessilifolia (0.25mg), Rhynchospora alba (0.87mg) and Moliniopsis japonica (1.82mg). The experiments were conducted in three successional stages with 0-, 4- and 9-cm thick litter layers.ResultsSeed emigration decreased and seed retention increased with an increase in litter thickness. Large seeds were retained within the litter throughout the experimental period, and fewer seeds were buried in peat compared to small seeds trapped by thick litter, which had shifted downward by the following early spring. Litter contributed to increasing the number of viable and ungerminated seeds. The number of viable seeds for all species was nearly zero on the bare peat surface. The numbers of viable seeds on and beneath the peat surface increased with increases in litter cover thickness.ConclusionsThe patterns of secondary seed dispersal and the availability of viable seeds were altered by litter accumulation through the progress of succession. Moreover, the effects of litter on seeds varied among species for which seed size differed. Overall, our results suggest that temporal changes in litter thickness through the progress of succession can play an important role in seed bank formation, which has potential impacts on the long-term dynamics of plant populations and the whole community.
  • Shiro Tsuyuzaki, Kenji Narita, Yuki Sawada, Koichiro Harada
    ECOLOGICAL RESEARCH 28 6 1061 - 1068 2013年11月 [査読有り][通常論文]
     
    We aimed to detect the trajectories of forest-floor vegetation recovery in a Picea mariana forest after a wildfire. Since fire severity in boreal forests is expected to increase because of climate changes, we investigated the effects of ground-surface burn severity, a surrogate for overall fire severity, on the revegetation. We annually monitored vegetation < 1.3 m high in 80 1 m x 1 m quadrats at Poker Flat Research Range (65A degrees 12'N, 147A degrees 46'W, 650 m a.s.l.) near Fairbanks, interior Alaska, where a large wildfire occurred in the summer of 2004, from 2005 to 2009. Sphagnum mosses were predominant on the unburned ground surface. In total, 66 % of the ground surface was burned completely by the wildfire. Total plant cover increased from 48 % in 2005 to 83 % in 2009. The increase was derived mostly by the vegetative reproduction of shrubs on the unburned surface and by the immigration of non-Sphagnum mosses and deciduous trees on the burned surface. Deciduous trees, which had not been established before the wildfire, colonized only on the burned surface and grew faster than P. mariana. Although species richness decreased with increasing slope gradient, these deciduous trees became established even on steep slopes. The wildfire that completely burned the ground surface distorted the revegetation, particularly on steep slopes. The restoration of the Sphagnum surface was a prerequisite after the severe wildfire occurred, although the Sphagnum cover had difficulty returning to predominance in the short term.
  • Hoyo, Y., Tsuyuzaki, S.
    American Journal of Botany 100 5 817 - 823 2013年 [査読有り][通常論文]
     
    Premise of the study: Although nondestructive, convenient species identification is desirable for follow-up research and species conservation, species identification is often confusing, particularly when an interspecific hybrid shows intermediate morphological characteristics between the parental species.Methods: Drosera anglica Hudson (2n = 40) and D. rotundifolia L. (20) bear the hybrid Drosera obovata Mert. et Koch (30). The samples were identified based on seed fertility and a cytological investigation (DNA amount) before examination. Then, 13 measured morphological traits-including leaf size, leaf shape, and flowering-were used in a canonical discriminant analysis (CDA). Leaf length and width were used in a hierarchical Bayesian model (HBM).Key results: The majority of the traits of D. obovata were intermediate between the two parental species. However, D. obovata developed larger leaves than the parental species. The identification error of the CDA based on the 13 morphological traits was 4.9%. Errors occurred more often with smaller leaves. When the CDA was used for blade length and width only, the error increased to 6.2%. The HBM, based on the relationships between blade length and width, showed the lowest identification error-4.7%-by improving the identification of small leaves.Conclusions: The HBM enabled convenient, nondestructive measurements for species identification by considering nonlinear relationships between morphological traits and measurement error. The HBM is likely to be applicable to various follow-up studies, as well as species conservation.
  • Koyama, A., Tsuyuzaki, S.
    Journal of Vegetation Science 24 3 473 - 483 2013年 [査読有り][通常論文]
     
    Questions Does the facilitation of herbaceous species seedling establishment by tussock-forming species collapse in an extreme drought year? Do different germination phenologies, between the seedling species, influence the variation in facilitation? Location A post-mined Sphagnum peatland at Sarobetsu mire, Hokkaido, northern Japan. Methods The effects of tussock-forming species, as potential facilitators, on seedling emergence and survival of five perennial herbs were examined during a 4-yr seedling monitoring, which included an extreme drought. The general effects of tussocks on each seedling species during annual variations were simultaneously assessed using hierarchical Bayesian analysis. To examine the stress limiting seedling establishment, which was ameliorated by the tussocks, micro-environments (i.e. light, temperature, water content and erosion) altered by morphological traits of the tussocks with litter cover were compared to those in open areas. Results In general, tussocks facilitated seedling establishment of all species through a positive effect on emergence and no effect on survival; however, the facilitative effect declined for several species in an extreme drought year. Peat erosion was the limiting stress on seedling establishment in normal years, however, peat water content also limited seedling establishment in a drought year. During the drought year, the positive effect of tussocks on seedling emergence for species that germinated before or during the drought was weakened for one species, and a negative effect on seedling survival emerged in another species. In contrast, species that germinated after the drought did not exhibit annual variation in the effects of tussocks on seedling emergence and survival. Conclusions Our results illustrate that collapse of facilitation arises under extremely severe conditions through addition of infrequently occurring stress (drought) on frequently occurring stress (peat erosion). Variation in seedling emergence and survival of the five study species in response to severe drought suggests that species-specific traits must be considered when assessing how facilitation varies temporally. Further, these findings suggest that facilitation in temporally varying environments can drive plant community composition and dynamics.
  • Asuka Koyama, Shiro Tsuyuzaki
    PLANT ECOLOGY 213 11 1729 - 1737 2012年11月 [査読有り][通常論文]
     
    In stressful and disturbed ecosystems, seedling establishment may be facilitated by early colonizing plants. We examined the mechanism of such facilitation by tussock-forming species (Carex middendorffii and Eriophorum vaginatum), focusing on the independent and interactive effects of tussock litter and tussock mound substrate. Shading by litter on tussock mounds provides a stable but dryer substrate that may negatively affect early colonizers, owing to the co-occurrence of light deficiency and limited water availability, but positively affect late colonizers by subsequent amelioration of water availability. We used seed sowing and seedling transplant experiments with un-manipulated tussocks and manipulated shading x tussock mounds to examine seedling emergence, survival, and the biomass of early (Moliniopsis japonica) and late (Lobelia sessilifolia) colonizers in a post-mined peatland in northern Japan. Carex and Eriophorum tussocks facilitated seedling emergence and the growth of M. japonica and L. sessilifolia. Manipulation experiments indicated that the major positive effect was in providing stable substrates for seeds and seedlings. While the survival and growth of both colonizers were unaffected by shading alone and were negatively affected by tussock mounds alone, shading on tussock mounds decreased both the survival and growth in M. japonica but increased it in L. sessilifolia. Overall, tussock mounds with litter shading accelerated seedling establishment, especially that of late colonizers, in post-mined peatland. Our results indicate that the importance of facilitation mechanisms, for early successional plant composition that result from independent and interactive processes that co-occur as environmental conditions change.
  • Shiro Tsuyuzaki
    Feddes Repertorium 122 3-4 275 - 286 2012年 [査読有り]
  • Shiro Tsuyuzaki, Miyuki Matsuda, Munemitsu Akasaka
    Climate Research 51 1 1 - 10 2012年 [査読有り][通常論文]
     
    To detect the effects of a deciduous shrub Salix reinii on microclimate along a gradient of elevation during the snow-free period, we measured ground surface temperature and surface photosynthetically active radiation (PAR) for bare ground and S. reinii patches (henceforth 'patches'). Measurements were made at low (560 m above sea level), middle (665 m), and high (755 m) elevations on the Mount Koma volcano in northern Japan. Soil water content was also measured for bare ground and under S. reinii patches at the middle elevation, and wind speed was measured on bare ground at all 3 elevations. The forest canopy, dominated by Larix kaempferi, was more developed at lower elevations, and wind speeds there were lower. The PAR value in patches decreased with increasing foliage, which also reduced temperature fluctuations at all 3 elevations. The water content remained higher in patches than on bare ground. These observations show that shrub cover markedly reduces temperature fluctuation and soil desiccation by intercepting solar radiation. Differences in microclimate between the 3 elevations were less in the shrub patches, showing that the patches weakened the effects of elevation and canopy on microclimate at each of the elevations surveyed.
  • Hideo Kimura, Shiro Tsuyuzaki
    APPLIED VEGETATION SCIENCE 14 3 350 - 357 2011年08月 [査読有り][通常論文]
     
    Questions: How does the severity of prescribed fires affect vegetation and seed bank in a wetland?Location: A fire-prone reed swamp in northern Japan (250 ha, 40 degrees 49'N, 141 degrees 22'E, < 10 m a.s.l.).Methods: Vegetation, biomass and seed bank were monitored for the 2 yr after annual prescribed fires were discontinued. Plant communities were placed into three categories based on fire severity: high (H) - fire consumed litter completely; moderate (M) - fire removed standing litter but left wet fallen litter; and low (L) - fire incompletely removed standing litter and did not remove fallen litter. Soil samples were collected in autumn 2007 and early summer 2008, and germinable seed bank was investigated by greenhouse trials.Results: High fire severity increased diversity in the next growing season by the establishment of short herbs in the standing vegetation. The biomass of forbs and grasses was greater in H where Phragmites australis biomass was reduced. The density of seed bank was > 30 000 seeds m(-2) throughout all the treatments. Perennial plants were dominant in the vegetation, while annuals, biennials and rushes were dominant in the seed bank. Small seeds were more abundant in the soil than in the litter. Qualitative and quantitative similarities between seed bank and the vegetation were low, and tended to be higher in H.Conclusions: Fire contributed to the development of diverse standing vegetation via the positive effects on seed bank dynamics, and can be considered a tool to maintain species-rich marshes.
  • Chika Egawa, Shiro Tsuyuzaki
    PLANT ECOLOGY 212 3 369 - 381 2011年03月 [査読有り][通常論文]
     
    The seedling establishment of late colonizer may be promoted in the environments created by the early colonizer without interspecific seedling competition. To confirm the hypothesis, seed-sowing experiments were conducted in a post-mined peatland, northern Japan. Seeds on three grasses (Rhynchospora alba, Moliniopsis japonica and Phragmites australis) were sown in four vegetation sites: bareground, R. alba grassland, M. japonica grassland, and grassland mixed with three examined species. R. alba is the earliest colonizer, and M. japonica and P. australis are the later ones. Seedling emergence, survival, growth and resource allocation were monitored for two growing seasons. The seedling emergence of all the species was lowest on bareground. The emergence of R. alba and P. australis was high in R. alba and mixed grasslands, but was low in M. japonica grassland. M. japonica seedlings emerged more in vegetation with moderate plant cover and litter. R. alba seedlings yielded the highest biomass on bareground, and the biomass decreased with increasing shading. R. alba did not change resource allocation of height to above-ground biomass between vegetation types. The seedling biomass of M. japonica was affected little by shading, probably because M. japonica adjusted resource allocation with shading. In the two summers, R. alba and M. japonica seedlings survived more when the neighboring seedlings emerged more. P. australis seedlings failed in overwintering. The seedling characteristics of each species explained the species replacement, i.e., R. alba invaded bareground and facilitated the establishment of late colonizer, M. japonica, by the shelter effects of the overstory and seedling.
  • K. Irie, S. Tsuyuzaki
    PLANT BIOSYSTEMS 145 4 798 - 801 2011年 [査読有り][通常論文]
     
    Aesculus turbinata acorns were dispersed earlier than other acorn-producing species and are removed completely by rodents, although the acorns are unpalatable. The dispersal timing and low palatability to rodents on A. turbinata acorns promote the seed caching by rodents, facilitating the seedling emergence is possible even in lower-seeding years.
  • H. Iwata, M. Ueyama, Y. Harazono, S. Tsuyuzaki, M. Kondo, M. Uchida
    SOLA 7 105 - 108 2011年 [査読有り][通常論文]
     
    Observations of carbon dioxide (CO2) flux with the eddy covariance technique were conducted at a burned boreal forest site five years after a wildfire and at a mature forest site in Interior Alaska to investigate the effects of wildfire on CO2 exchange in a boreal forest. Both gross primary productivity and ecosystem respiration were lower at the burned site. The lower amount of vegetation explains the lower gross primary productivity and ecosystem respiration at the burned site. The reduced soil organic layer at the burned site further explains the lower respiration. On an annual basis, the five-year-old burned site was a CO2 sink, which indicated earlier recovery of CO2 exchange compared to other burned boreal forests in North America reported in the literature. The quick recovery of net CO2 exchange is associated with constrained heterotrophic respiration, rather than recovery of vegetation. Burn severity can be a key variable in determining CO2 exchange during the early stage of succession after wildfire.
  • Shiro Tsuyuzaki
    SEED SCIENCE RESEARCH 20 3 201 - 207 2010年09月 [査読有り][通常論文]
     
    Seed longevity in situ is a prerequisite for understanding the life histories and community dynamics of species, although long-term longevity under thick tephra has not been documented because of a lack of opportunity and/or awareness. The seed bank for this study was estimated by both germination and flotation tests. Seeds of 17 species have survived with high density, having been buried under thick tephra for 30 years, since the 1977-1978 eruptions on Mount Usu, Hokkaido Island, northern Japan. The total seed density was > 1000/m(2). Rumex obtusifolius was the most common seed-bank species for 30 years, but decreased in density between 20 and 30 years. More seeds of Hypericum erectum occurred in deeper soil. The total seed density decreased gradually for 30 years, but H. erectum and Juncus effusus did not decline. Native seeds tended to be viable longer than exotic seeds. These results suggest that small, native seeds tend to survive longer with deep burial, while the more numerous weedy, exotic seeds located at the soil surface declined faster. The seed bank provides long-term monitoring of seed survival under natural conditions, and could be used to detect genetic changes.
  • Asuka Koyama, Shiro Tsuyuzaki
    WETLANDS ECOLOGY AND MANAGEMENT 18 2 135 - 148 2010年04月 [査読有り][通常論文]
     
    Facilitation (positive inter-specific interaction) plays an important role in promoting succession in harsh environments. To examine whether tussocks facilitate the establishment of other species, after peat mining, investigations were carried out in a formerly Sphagnum-dominated wetland (Sarobetsu mire, northern Japan). Two tussock-forming species, Carex middendorffii and Eriophorum vaginatum, have established in sparsely vegetated areas, with a dry ground surface, since peat extraction ended. The following factors were examined, in three microhabitats created by tussocks (center = raised tussock center, edge = tussock edge covered with litter, and flat = flat areas without tussocks): (1) relationships between tussock microhabitats and plant distributions, and (2) the effects of tussocks on survival, growth, flowering and seed immigration of common species. Two (1 x 10 m) plots were established, in each of three sparsely vegetated sites, in September 2005. Tussocks were mapped in each plot, and species, location, flowering, growth stage (seedling, juvenile and fertile) and size of all plants were recorded, during snow-free periods from September 2005 to September 2006. Seed traps were used to investigate seed dispersal from June to October 2006. Four native species, Drosera rotundifolia, Lobelia sessilifolia, Moliniopsis japonica, Solidago virgaurea, and an exotic species, Hypochaeris radicata, were most common. During seedling and juvenile stages, these species were distributed more densely at the tussock edge than in the flat areas, but were less common at the center. H. radicata had a higher survival rate at the edge than in the flat during the winter. The annual growth of H. radicata, L. sessilifolia and S. virgaurea was higher at the edge. Seed traps detected that D. rotundifolia seeds accumulate more at the edge. In conclusion, tussocks facilitated plant establishment in the edge microhabitat by providing litter cover, enhancing seed accumulation, germination and survival, and thus promoted revegetation. However, Sphagnum mosses have not established in the study sites, and the vegetation differs strongly from the areas where no peat mining had taken place.
  • Shiro Tsuyuzaki, Nobusyoshi Sento, Masami Fukuda
    POLAR BIOLOGY 33 4 565 - 570 2010年04月 [査読有り][通常論文]
     
    To understand how baidzharakhs (relic mounds enclosing polygonal ice blocks in permafrost) affect the zonal distribution of vegetation, vegetation was measured in 145 plots of area 50 cm x 50 cm on a coastal terrace facing the Arctic Ocean in northern Siberia. Cluster analysis classified five community types that were zonally distributed along the coastline. alpha-diversities (species richness and diversity) were not different among vegetation types except for vegetation close to the coastline. On and around baidzharakhs, burrows created by lemmings were frequently observed, and plant cover was low, suggesting that baidzharakhs support habitats for rodents. Disturbances by rodent habits caused plant cover to decline but did not change alpha-diversity. Two vegetation types that developed only on baidzharakhs were found at intermediate distances between the seacoast and inland areas. Because these two vegetation types are azonally distributed, beta- and gamma-diversities were increased by permafrost-derived topography, i.e., baidzharakh, and/or disturbance by rodents of which suitable nesting habitat is provided by baidzharakh.
  • S. Tsuyuzaki, J. H. Titus
    IFOREST-BIOGEOSCIENCES AND FORESTRY 3 52 - 55 2010年03月 [査読有り][通常論文]
     
    Roadside grassland vegetation in a Quercus garryana forest, that is one of the dominant species in west Cascade, on the Oak Creek Wildlife Area, Naches, Washington, USA, was investigated to determine the patterns of human impact on the vegetation along mountain trails. Vegetation and environmental data were collected on forty-eight 50 cm x 50 cm plots. Plot cover ranged from 3 to 100% (1 to 8 species) and most of the cover was from exotic species. In order to explore vegetation patterns the following environmental variables were measured: slope, tree canopy area, bare area, distance from road, and litter thickness. The vegetation data and environmental variables were examined using Canonical Correspondence Analysis (CCA). CCA showed that canopy area played important roles in vegetation development. Litter thickness and soil firmness also seemed to be related to the vegetation pattern. Distance from the road affected plant cover but was not related to canopy area, and litter thickness, suggesting that the distance was not a prime determinant on the vegetation pattern a priori. Species richness was the highest in mid-vegetation cover plots, i.e., 40-60%. An exotic plant, Sisymbrium officinale, increased in frequency with a decrease in vegetation cover, and two exotic plant species, Achillea millefolium and Anthoxanthum odoratum, occurred with S. officinale. S. officinale may be a good indicator for evaluating environmental deterioration. The preservation of canopy cover is of prime importance for nature conservation in forested recreational areas.
  • Shiro Tsuyuzaki
    JOURNAL OF VEGETATION SCIENCE 20 5 959 - 969 2009年10月 [査読有り][通常論文]
     
    Question: How do temporal changes in plant communities occur after volcanic eruptions? What characteristics determine successional divergence or convergence?Location: The summit area Of Mount Usu, northern Japan, completely destroyed by 1-3 m of thick ash and Pumice during the 1977-1978 eruptions. Habitats were classified into three types: gullies where the pre-eruption topsoil was exposed due to the erosion of tephra (EG), gullies covered with tephra (CG), and Outside of gullies covered with thick tephra (OG).Methods: Plant community structure was monitored for 15 years from 1983 to 1997 in 14 2m x 5m permanent plots. The data were Summarized by species diversity, life form, and the detrended correspondence analysis.Results: The common species were perennial herbaceous plants, but habitat preferences differed between species. Seed bank species, including a nitrogen fixer Trifolium repens, were dominant in EG, and excluded the establishment of the later colonists. Pioneer trees slowly increased in cover. The detrended correspondence analysis indicated that species composition in the earlier stages did not differ greatly between plots. Thereafter, three patterns of temporal community changes Were observed: seed bank species persisted in EG, and in OG and CG forest development proceeded or community structure did not change greatly.Conclusion: Pre-eruption topsoil contributed to revegetation by the supply of seed bank and nutrients in the earliest stages, but resulted in the delay of forest development due to the persistence of seed bank species. Plant community divergence was driven by the persistence of earlier colonists.
  • Chika Egawa, Asuka Koyama, Shiro Tsuyuzaki
    PLANT ECOLOGY 203 2 217 - 228 2009年08月 [査読有り][通常論文]
     
    To clarify seedbank developmental pattern and its determinants, we examined relationships between seedbank, standing vegetation, and litter in a post-mined peatland on Sarobetsu Mire, northern Japan. In late fall 2006 and early summer 2007, peat was sampled from four vegetation types, and litter was also sampled from two of the four vegetations where thick litter was accumulated. Seed germination tests were performed by the samples in a glasshouse. The results were compared between the standing vegetation and litter accumulation. Seed density and species richness in seedbank gradually increased with increasing vegetation cover. Seeds in surface layer germinated more in fall than in summer. In vegetation with thick litter, small seeds, such as Drosera rotundifolia and Gentiana triflora, germinated more from peat than from litter in summer, probably due to the downward movement. Seed density in litter decreased from fall to the next summer. Moliniopsis japonica and Rhynchospora alba developed short-term persistent seedbank, whereas D. rotundifolia and G. triflora preserved long-term persistent seedbank in peat covered with thick litter. Seedbank development follows the development of the standing vegetation with litter. Litter derived from the standing vegetation is a prime determinant on the seedbank composition and development, by acting as seed trap and keeping seed dormancy.
  • Shiro Tsuyuzaki, Akira Haraguchi
    Journal of Forestry Research 20 2 91 - 98 2009年06月 [査読有り][通常論文]
     
    There is an abrupt boundary between two well-developed wetland forests, a stand consisting of a broad-leaved, nitrogen-fixer Alnus japonica and a stand of the needle-leaved Picea glehnii Masters, in eastern Hokkaido, Japan. To clarify maintenance mechanisms, we studied the forest profile, water level, groundwater and precipitation chemistry, seedling establishment patterns in relation to microhabitats, and seed migration. The profile of groundwater level insufficiently explained the abrupt boundary formation, while the groundwater chemistry differed significantly between the two forests i.e., EC, Na +, K+, Mg2+, Ca2+ and Cl- were higher in P. glehnii forest and pH was lower. Precipitation in P. glehnii forest contained richer Na+, Ca2+ and Cl-, indicating that the differences in surface-water chemistry were mostly derived from precipitation. Solar radiation was less than 2.2 MJ•m -2•d-1 on P. glehnii forest in late June, while that was patchily distributed in A. japonica forest with a range from 1.0 to 3.7 MJ•m-2•d-1. Moss cover on the soil surface, most of which were made of Sphagnum spp., was 60% in P. glehnii forest, but was 10% in A. japonica forest. Surface water chemistry represented by pH was considered to determine the development of Sphagnum moss. About 70% of P. glehnii seedlings < 1.3 m in height established on moss cover. Seed-sowing experiments suggested that seed germination and seedling survival for both species were significantly higher in P. glehnii forest. Therefore, the regeneration of P. glehnii in A. japonica forest was negligible, owing to the paucity of favorable microhabitats and low seedling establishment. A. japonica regenerated only by resprouting, and the seedlings were few in both forests. In addition, A. japonica seed migration into the P. glehnii forests was greatly restricted, and low solar radiation in the P. glehnii forest contributed to low seedling survival. Based on those results, we concluded that Picea glehnii and Alnus japonica could develop distinct and selfish environments being unsuitable for the other species and inhibit natural afforestation of another species each other by excluding invasion. © 2009 Northeast Forestry University and Springer-Verlag GmbH.
  • Munemitsu Akasaka, Shiro Tsuyuzaki
    PLANT ECOLOGY 202 2 235 - 245 2009年06月 [査読有り][通常論文]
     
    We monitored the recruitment, survival, and growth of tree saplings on invasive (Larix kaempferi) versus native species (Betula and Populus) using 16 20 m x 20 m plots established along elevation gradient on the volcano Mount Koma, Japan, for 7 years because the sapling behaviors should determine forest structures. The crowding of overstory consists mostly of Larix decreased with increasing elevation. Larix recruits were conspicuous, particularly at middle elevation where overstory crowding was intermediate, while Betula recruits were least. Larix overstory crowding inhibited the recruitment of all the taxa, although intermediate crowding promoted the recruitment of Larix. The restriction of sapling emergence was conspicuous at lower elevation where the overstory crowding was highest, probably because of shading, and/or competition with overstory trees. Sapling recruitment for all taxa was restricted at higher elevation, due to high stresses derived from direct solar radiation and strong wind without overstory. The survival of saplings was 96% for Larix and Betula, while it was ca. 50% for Populus. Larix overstory decreased the survival and growth of all the taxa, except Larix survival and Betula growth. The results implied that Larix could establish by high survival once the recruits succeeded everywhere and native sapling regeneration was restricted by Larix overstory. Strong recruitment, survival, and growth of Larix, together with resistance to overstory crowding, enables it to dominate and persist in such disturbed areas regardless of the canopy closure.
  • S. Tsuyuzaki, C. Miyoshi
    PLANT BIOLOGY 11 3 369 - 378 2009年05月 [査読有り][通常論文]
     
    The effects of smoke, heat, darkness and cold stratification on seed germination were examined for 40 species with various life history attributes. These species establish in early successional stages on a volcano and are distributed in cool temperate zones of northern Japan. Smoke decreased seed germination in 11 species and increased it in one species, Leucothoe grayana. Germination of Polygonum longisetum was enhanced by a combination of smoke and cold, and that of Aralia elata by smoke and heat. Heat increased germination for three species and decreased it for one. Cold stratification broke dormancy in seeds of 11 species. Continuous darkness decreased germination of 22 species and did not increase germination for any species, showing that approximately half of the species require light for maximum germination. Although most species are sun plants that establish in early stages of succession and/or in disturbed areas, smoke and heat do not enhance germination of these species after disturbance, even when the disturbance is fire. Germination of slender and/or large seeds tends to be decreased more by smoke, probably because of their larger surface area. Light is more important than smoke and heat for detection of disturbance and for seed germination in this region. However, despite the low fire frequency in the region, germination of a few species was increased by fire-derived stimuli.
  • Shiro Tsuyuzaki, Keiji Kushida, Yuji Kodama
    CLIMATIC CHANGE 93 3-4 517 - 525 2009年04月 [査読有り][通常論文]
     
    Albedo influences vegetation structure, permafrost thawing, etc., in particular, after wildfires in Picea mariana forests in Alaska, USA, while albedo changes with plant succession. To understand interactions between albedo and ecosystem recovery after wildfire, surface albedo was measured in the spring and summer of 2005 at Poker Flat, interior Alaska, where P. mariana forest was dominant. The ground surface was mostly covered with Sphagnum moss before the 2004 wildfire, and was variously burned by the fire. The measured wavelengths ranged from 0.3 to 3.0 mu m. We measured four independent variables, incidence, plant cover on the forest floor, cover of burned ground surface, canopy openness and incidence, to examine the determinants on surface albedo. Multiple regression analysis showed that total plant cover positively and mostly determines albedo, indicating that plant recovery is prerequisite to return high albedo. When the ground surface was damaged by fire, changes in albedo were mostly derived from decrease in reflectance wavelengths between 0.7 and 1.4 mu m. The fluctuations of reflectance wavelengths did not differ greatly between damaged-moss and burned surfaces. We must mention the dynamics of Sphagnum to understand various environmental changes including surface albedo.
  • Aiko Nishimura, Shiro Tsuyuzaki, Akira Haraguchi
    ECOLOGICAL RESEARCH 24 2 237 - 246 2009年03月 [査読有り][通常論文]
     
    The aim of this study is to detect how vegetation development proceeds after Sphagnum-peat mining and how physical and chemical factors in groundwater are related to the revegetation patterns in Sarobetsu mire, Hokkaido, Japan. A total of 189 plots on peat-mining sites were set in a chronosequence and 18 plots were set on unmined control sites. A vegetation survey was conducted, and seasonal changes in groundwater levels and chemistry (pH, electrical conductance, total nitrogen, total phosphorus, anions, and cations) were monitored. Species richness and plot cover tended to increase with increasing age, but were significantly lower in mined sites than in unmined sites dominated by Sphagnum spp. The trends in vegetation change were (1) bare ground, (2) grasslands dominated by grasses and sedges, e.g., Rhyncohospora alba, Phragmites communis, and Moliniopsis japonica and (3) Sphagnum-dominated vegetation. The characteristics of groundwater level during the plant-growth period mostly determined vegetation recovery, i.e., Sphagnum establishment was promoted when groundwater declined greatly in early summer. The patterns of temporal vegetation changes affected by groundwater characteristics were detected by chronological sequence, and hydrological factors in groundwater were more important for revegetation than chemical factors. The original vegetation has not returned after three decades.
  • K. Kushida, Yongwon Kim, S. Tsuyuzaki, M. Fukuda
    INTERNATIONAL JOURNAL OF REMOTE SENSING 30 6 1651 - 1658 2009年 [査読有り][通常論文]
     
    Using field observations, we determined the relationships between spectral indices and the shrub ratio, green phytomass and leaf turnover of a sedge-shrub tundra community in the Arctic National Wildlife Refuge, Alaska, USA. We established a 50-m 50-m plot (69.73N 143.62W) located on a floodplain of the refuge. The willow shrub (Salix lanata) and sedge (Carex bigelowii) dominated the plot vegetation. In July to August 2007, we established ten 0.5-m 0.5-m quadrats on both shrub-covered ground (shrub quadrats) and on ground with no shrubs (sedge quadrats). The shrub ratio was more strongly correlated with the normalized difference vegetation index (NDVI, R2 of 0.57) than the normalized difference infrared index (NDII), the soil-adjusted vegetation index (SAVI) or the enhanced vegetation index (EVI). On the other hand, for both green phytomass and leaf turnover, the strongest correlation was with NDII (R 2 of 0.63 and 0.79, respectively).
  • Shiro Tsuyuzaki, Yuki Sawada, Keiji Kushida, Masami Fukuda
    ECOLOGICAL RESEARCH 23 4 787 - 793 2008年07月 [査読有り][通常論文]
     
    We measured vegetation patterns on palsas with reference to topographic characteristics on the Arctic National Wildlife Refuge, northern Alaska, to obtain benchmark data because of the changes expected from global warming. Vegetation was examined in 60 plots of area 50 cm x 50 cm by five environmental factors: water content in the peat and duff layers, groundwater level, slope angle, depth to frozen surface, and presence of pellets and feces. Three palsas were selected for the survey, and the heights were fewer than 50 cm from the groundwater surface. Based on TWINSPAN and canonical correspondence analysis, we confirmed that clear patterns of vegetation zonation had developed within a 60-cm difference in water level. Vaccinium vitis-idaea occurred well on the top areas of palsas, while Carex aquatilis was established on the bottom areas. Sphagnum spp. were established on intermediate locations between V. vitis-idaea and C. aquatilis. The prime determinant of the vegetation zonation seems to be water content in peat and duff layers rather than water level, although the five factors that we examined interact intricately with each other.
  • S. Tsuyuzaki, M. Haruki
    LAND DEGRADATION & DEVELOPMENT 19 3 233 - 241 2008年05月 [査読有り][通常論文]
     
    The effects of microtopographical characteristics of the thick accumulation of ash and pumice, which were produced from 1977-78 eruptions, on seedling emergence and survival were monitored on the volcano Usu, northern Japan, 10 years after the eruptions. The characteristics included inicrotopography, texture of volcanic deposits on ground surface, volcanic-deposit movements, water content on ground surface and chemical nature of volcanic deposits (ignition loss, P, K and pH). Polygonum sachalinense showed a higher seed germination percentage on finer-particle ground surface under lab conditions, and Petasites japonicus var. giganteits germinated well on the ground surface with any particle sizes. However, in the field, the seedling densities of those two species and Anaphalis margaritacea var. angustior (three dominant species in this region) were higher on the sites with coarse particles and/or the rill inside the crater basin. The seedling germination timing and space overlapped among these species in the field. Those facts suggested that the seedling colonisation pattern was influenced more by the topographical characteristics of ground surface rather than the germination abilities. The amount of organic matter in the volcanic deposits was very low, even I I years after the eruptions, and was not related to microtopography, suggesting that the effects of organic matter on seedling emergence did not differ along microtopographical characteristics. Inside of rills, higher water content seemed to be more advantageous for seed germination of those species. Volcanic deposits were physically stable in summer, but were heavily eroded after winter due to snowmelt. Most seedlings did not overwinter in the inside of rills with pumice where the volcanic deposits eroded intensively, indicating that the patterns of land degradation by melting snow should be mentioned carefully even with narrow scale. Copyright (c) 2007 John Wiley & Sons, Ltd.
  • T. B. Nishimura, E. Suzuki, T. Kohyama, S. Tsuyuzaki
    Plant Ecology 193 2 315  2007年12月 [査読有り][通常論文]
  • T. B. Nishimura, E. Suzuki, T. Kohyama, S. Tsuyuzaki
    PLANT ECOLOGY 193 2 315 - 315 2007年12月 [査読有り][通常論文]
  • Munemitsu Akasaka, Akira Hase, Shiro Tsuyuzaki
    Journal of Plant Research 120 2 329 - 336 2007年03月 [査読有り][通常論文]
     
    To investigate the seedling growth of a biologically invasive larch Larix kaempferi (Lamb.) Carr. on Mount Koma, Japan, seedlings were excavated from three microhabitats (bareground = BA, Salix reinii patch = SP, and Larix understory = LU) in three elevational zones. Seedlings showed the highest ectomycorrhizal (ECM) colonization percentage in the most shaded microhabitat, LU. ECM colonization percentages in BA and SP were found to decrease with decreasing elevation. These results inferred that the ECM colonization percentages were related to seedling growth, particularly in BA and SP. However, the annual seedling growth was not synchronized with the increases in either elevational gradients. Although ECM colonization was most evident in LU, the seedling growth was the lowest. We concluded that the effects of ECM colonization on seedling growth were reduced mostly by microhabitat characteristics.
  • T. B. Nishimua, E. Suzuki, T. Kohyama, S. Tsuyuzaki
    PLANT ECOLOGY 188 2 165 - 177 2007年02月 [査読有り][通常論文]
     
    Lowland forests in Central Kalimantan, Indonesian Borneo, are endangered by land conversion and the increasing frequency of severe drought. Knowledge of the tolerance of tropical trees to drought is urgent for the management of these lowland habitats. The short-term effects of drought on tree demography (mortality and growth) were investigated in an ever-wet riparian peat-swamp forest and a heath forest on coarse sandy soil after the 1997 El Nino Southern Oscillation (ENSO) event. This drought was unusually severe because little rain fell during the following rainy season. However, forest-wide mortality following the drought (1997-1999) was not critically high in the peat-swamp (6.13% yr(-1)) or heath (4.26% yr(-1)) forest. In both forests, standing trees frequently died during the dry season following the drought. The riparian peat-swamp forest was not flooded until 1998, after the prolonged drought in 1997. The hummock-hollow microtopography resulted in differential mortality of peat-swamp trees. On tall hummocks, standing death increased two-fold (4.99% yr(-1)) during the dry season, whereas uprooting decreased by one-third (0.85% yr(-1)) during the following rainy season. In contrast, tree growth was not affected by hummock height. Common canopy species were concentrated on tall hummocks and died standing more often than did understory species found in hollows, indicating species-specific mortality after the drought. The large stand basal area relative to the forest-wide growth rate in diameter suggested less resilience to drought by peat-swamp (45.6 m(2) ha(-1) and 0.0186 ln[cm] yr(-1)) than heath (27.9 m(2) ha(-)1 and 0.0232 ln[cm] yr(-1)) forest. A single severe drought did not cause dramatic changes in the peat-swamp and heath forests; however, an increasing frequency of droughts similar in severity to that of the 1997 ENSO event may have the potential to alter the community structure and dynamics, leading to a consistent decline in Bornean lowland forests.
  • S. Tsuyuzaki, H. Takahashi
    Applied Ecology and Environmental Research 5 2 25 - 36 2007年 [査読有り][通常論文]
     
    Decrease in species diversity by overgrazing is one of the crucial indicators for ecosystem deterioration. Sika deer (Cervus nippon Tamminck) has grazed various plants on Nakajima Island, Hokkaido, Japan, for a few decades, due to low food availability. We examined if diverse microtopography supported high species diversity by conserving specific plants on the grassland of the island where overgrazing by deer occurred. Based on TWINSPAN analysis, three plant community types were classified: grasslands represented by short seed plants, ferns, and unpalatable forbs. Grasslands dominated by short and/or unpalatable seed plants established on the flat ground, while fern species except Equisetum arvense did not establish there. Soil hardiness was higher on short-plant grasslands than on unpalatable-forb grasslands, suggesting that palatability on plants was related to plant community differentiation on the flat ground. Of 10 fern species recorded, 9 species established mostly in deep pits. Pit depth was more important than pit area to maintain high fern diversity. Those results indicated that diverse microtopography, i.e., pit development, supports fern diversity, because of the multiplier effects of predator avoidance and preferable sites for fern establishment. Diverse and/or specific microtopography must be a prerequisite to conserve rare species and high diversity in such disturbed areas. © 2007, Penkala Bt.
  • Survival and changes in germination response of Rumex obtusifolius, Polygonum longisetum and Oenothera biennis during burial at three soil depths
    Shiro Tsuyuzaki
    American Journal of Environmental Sciences 2 74 - 78 2006年 [査読有り][通常論文]
  • TSUYUZAKI S
    Lyonia 11 35 - 41 2006年 [査読有り][通常論文]
  • M Akasaka, S Tsuyuzaki
    JOURNAL OF VEGETATION SCIENCE 16 6 647 - 654 2005年12月 [査読有り][通常論文]
     
    Questions: How do biological invasion patterns of Larix kaempferi seedlings change with different microhabitats along an elevational gradient on a volcano? How are seedling attributes such as establishment, competitive ability and morphological plasticity, advantageous to the invasion of stressful disturbed areas? Location: Mount Koma, Hokkaido, Japan. Methods: Seed sowing experiments and natural seedling censuses were conducted with L. kaempferi and the dominant native tree Betula ermanii. Seed germination, seedling survival and allocation were investigated on three microhabitats (bare ground, Salix reinii patch and Larix understorey) in three elevational zones for three years. Results: Seed germination was higher in Larix understorey than in bare ground and Salix patches, but did not differ between elevations. Survival rates were not different between elevations and microhabitats. Larix had a higher survival rate than Betula. Larix showed the highest natural seedling density in Salix patches, independent of elevational differences, while Betula density was nearly zero. Larix seedlings changed allocations between microhabitats, while the ratio of leaf to total biomass was constant. In bare ground Larix was more stunted and branched and increased its allocation to the roots. This form is adaptive to windy, nutrient-poor environments. Larix seedlings were taller and more slender in Salix patches, indicating that the priority was light acquisition in shaded habitats. Little change in Betula allocation was detected. Conclusion: Invasive species establish themselves more efficiently than native species in every microhabitat investigated, especially at higher elevations, by having higher survival and growth rates derived from superior seedling performance. Plant communities on and above the tree line are modified by the biological invasion.
  • S Tsuyuzaki
    ECOLOGICAL INDICATORS 5 2 109 - 115 2005年05月 [査読有り][通常論文]
     
    Most ski slopes in Japan are established by forest clearcutting, scraping off the ground surface and thereby artificial seeding in well-developed forests. Recently, some ski slopes have been abandoned owing to economical failure, and more skis resorts will go bankrupt. To restore abandoned ski slopes, therefore, we have to find out appropriate indicators to restore forest cover with low cost. Vegetation data were collected in Yuzawa, central Honshu, Japan (500-760 m elevation), where ski slopes are over-concentrated. To predict the possibility of forest development, relationships between tree stem density and vegetation characteristics were examined. Trees did not establish in areas where the introduced plant cover was more than 40%. Of native grasslands, Miscanthus sinensis grassland showed the highest stem density but did not show high species richness. In particular, stem density increased with increasing M. sinensis cover. To indicate advanced successional sere towards forests, therefore, M. sinensis cover is a more appropriate indicator rather than species richness. (c) 2004 Elsevier Ltd. All rights reserved.
  • S Tsuyuzaki, A Hase, H Niinuma
    MYCORRHIZA 15 2 93 - 100 2005年03月 [査読有り][通常論文]
     
    To investigate the role of mycorrhizae in nutrient-poor primary successional volcanic ecosystems, we surveyed mycorrhizal frequencies on the volcano Mount Koma (42 degrees 04' N, 140 degrees 42' E, 1,140 m elevation) in northern Japan. After the 1929 eruptions, plant community development started at the base of the volcano. Ammonia and nitrate levels, along with plant cover, decreased with increasing elevation, whereas phosphorus did not. In total, 305 individuals of 56 seed plant species were investigated in three elevational zones ( 550 - 600 m, 650 - 700 m, and 750 - 800 m). Five mycorrhizal classes were classified based on morphological traits: ecto- (ECM), arbuscular ( AM), arbutoid, ericoid, and orchid mycorrhiza. All plant species were mycorrhizal to at least some extent, with most widespread tree species being heavily ectomycorrhizal. In addition, of 16 tree species collected in all three zones, 6 differed in the frequencies of ECM on roots between elevational zones, and 3 of these 6 species increased in frequency with increasing elevation. These results suggest that ECM colonization in some tree species is related to establishment in nutrient-poor habitats. All species of Ericaceae and Pyrolaceae had ericoid mycorrhizae, and an Orchidaceae species had orchid mycorrhizae. Herbaceous species, except for the low mycorrhizal frequency of Carex oxyandra and two Polygonaceae species, and ericoid and orchid mycorrhizal species, were generally AM. Of herbaceous species, Anaphalis margaritacea var. angustior increased AM frequency and decreased ECM frequency with increasing elevation, and Hieracium umbellatum increased ECM frequency. In total, the establishment of herbaceous species was not sufficiently explained by AM colonization on roots. Tree individuals developed 2 - 3 classes of mycorrhizae more than herbs at each elevational zone. We conclude that the symbiosis between seed plants and mycorrhizae, ECM in particular, greatly influences plant community structures on Mount Koma. Not only a single mycorrhizal class, but combinations of mycorrhizal classes should be studied to clarify effects on plant community dynamics.
  • S Tsuyuzaki, A Hase
    Folia Geobotanica 40 4 319 - 330 2005年 [査読有り][通常論文]
     
    A small eruption occurred in the early spring of 1996 on the summit of Mount Koma, northern Japan, 67 years after the 1929 catastrophic eruption. To identify damage on the plant communities and recovery patterns, we established 400 50 x 50 cm permanent plots in four locations along the gradient of the thickness of tephra produced in 1996: non-disturbed (N), weakly disturbed (W), middle disturbed (M), and heavily disturbed (H). Annual monitoring was conducted from 1996 to 2001. Gullies and rills formed in M and H, indicating that the ground surface movements were more intense there. Mean vascular plant species richness increased from H to N, but did not increase from 1996 to 2001 in any location. In an area where tephra thickness was 10 cm, the recovery was mostly conducted by the species that could have survived during the eruption. A shrub, Salix reinii, was the leading species in most sites throughout most years. Large perennial herbs, Polygonum weyrichii, P. sachalinense and Miscanthus sinensis were common in the disturbed areas, in particular in M and H. Those three species develop large underground organs and enlarge clonally, suggesting that the tolerance to ground surface stability is the most important trait for the recovery of those species. Carex oxyandra established not only by vegetative regeneration but also by seedling regeneration. A short forb, Campanula lasiocarpa, could establish only in W by seedling regeneration. Mosses and lichens were predominant in plots in N and W, but less represented and not greatly increasing their cover in M and H up to 2001. We concluded that the community recovery was delayed in all the disturbed areas, mostly due to low seedling establishment. Only a few specific species. established by vegetative reproduction. Disturbance gradients such as thickness of tephra and/or ground surface stability have determined plant community structure and development.
  • M Ishikawa-Goto, S Tsuyuzaki
    JOURNAL OF PLANT RESEARCH 117 3 245 - 248 2004年06月 [査読有り][通常論文]
     
    We compared two standard seed-bank estimation techniques using buried seed populations that had been covered to depths of >1 m by volcanic deposits for 20 years. Some seeds were germinated in a greenhouse (germination method [GM]), and other seeds were extracted by flotation using 50% K2CO3 solution (floatation method [FM]). In total, FM could detect more species and seeds in the soils than GM. However, many species that were extracted by FM did not germinate by GM and smaller seeds were extracted to a lesser extent by FM. FM and GM have distinct advantages and disadvantages. We concluded that the application of a single method should be avoided in estimating seed banks, in particular for long-lived seed banks, because the seeds cannot be readily germinated and are structurally weak.
  • H Nishi, S Tsuyuzaki
    ECOGRAPHY 27 3 311 - 322 2004年06月 [査読有り][通常論文]
     
    The interaction between frugivorous birds and trees producing bird-dispersed seeds in devastated areas has been considered to be weak, owing to the paucity of avifauna and/or food resources for birds. Here, we present evidence that strong interactions between birds and plants may promote the enlargement of tree distribution on harsh environments. The summit of Mount Koma, northern Japan, was denuded by the 1929 volcanic eruption. Vegetation cover gradually decreases from the bottom (secondary forest) to the top (bareground) of the mountain. We recorded 48 bird species in the four seasons of 2001, along a 5-km line transect on the southwestern slope of the mountain. Birds faeces collected along the transect contained seeds of more than 14 plant taxa. Five of the 14 taxa were bird-dispersal tree species (Rhus trichocarpa, Sorbus commixta, Prunus ssiori, Prunus maximowiczii and Prunus sargentii) and were established in the summit area. Most faeces were derived from Corvus spp. (mostly C. macrorhynchos) and Turdus naumanni. In particular, the seeds of R. trichocarpa were found mostly from the faeces of Corvus spp. and the seeds of Gaultheria miqueriana, a shrub species, were only from T. naumanni. Rhus trichocarpa retained fruits on the canopy at all times of the year, and crows could feed on them even when food resources were poor in winter. Rhus trichocarpa seedlings established well near rock at higher elevation, while they occurred mostly under the larch canopy of larches at lower elevation. Crows mostly utilized tree canopies and rocks as perches in respective habitats. Therefore, seedlings should be abundant in specific habitats at different elevations. Size-class distribution of seedlings suggested that seedling mortality was lower at higher elevation where open sites were more abundant. These findings indicate that strong mutual advantages for C. macrorhynchos and R. trichocarpa on denuded areas play an important role on revegetation.
  • S Tsuyuzaki, A Haraguchi, F Kanda
    ECOLOGICAL RESEARCH 19 3 349 - 355 2004年05月 [査読有り][通常論文]
     
    Herbaceous vegetation was examined in an Otanoshike wetland in northern Japan to clarify the relationships between vegetation patterns and environmental factors with different scales. Alders (Alnus japonica) have recently invaded and might modify the herbaceous vegetation. In total, 150 50 x 50 cm plots were established on the transitional areas between alder thickets and grassy marshland. Cover was measured for the vascular plant taxa, and canopy area, number of stumps, number of mounds, water depth, elevation difference, litter thickness, soil organic matter, and soil pH were measured in each plot. TWINSPAN cluster analysis classified four vegetation groups: (i), grasslands represented by Phragmites australis, Trientalis europaea, Lythrum salicaria, and Hosta rectifolia; (ii), Calamagrostis langsdorfii, and Polygonum thunbergii grasslands with Spiraea salicifolia; (iii), reed swamp dominated by Phragmites australis, and (iv), marshland dominated by Carex lyngbyei. Canonical correspondence analysis indicated that water depth primarily divided vegetation groups 1-2 and 3-4. Alder established in drier sites mostly by re-sprouting, and the canopy affected light and soil conditions on the ground surface. The second axis of canonical correspondence analysis was related to the canopy area and soil pH, and explained the vegetation differentiation between groups 1 and 2, and groups 3 and 4. In conclusion therefore, scale-dependent or hierarchical variables affected the vegetation patterns in different ways, that is, the herbaceous vegetation was first differentiated by water depth that was corresponding to alder establishment on a large scale, and subsequent light and soil conditions were second determinants on a small scale.
  • S Uesaka, S Tsuyuzaki
    PLANT ECOLOGY 175 2 165 - 177 2004年 [査読有り][通常論文]
     
    The effects of patches formed by a deciduous shrub (Salix reinii) and an evergreen shrub (Gaultheria miqueliana) on cohabitants were examined on an active volcano Mt. Koma, northern Japan, using bareground as a comparative baseline (control). Species richness increased with increasing the areas of three habitats (Salix patches, Gaultheria patches and bareground), but significantly slowed in Gaultheria patches where the shoot densities of cohabitants also decreased. Calamagrostis hakonensis and Spiranthes sinensis were 2-3 times more likely to establish in Salix patches than in bareground, Anaphalis margaritacea var. angustior and Campanula lasiocarpa were 4-5 times more likely to establish on bareground than in Salix patches. Cohabitants was fewer with Gaultheria. Light intensities of the two patch types were ca 1/3 of that on bareground. Light intensity on Gaultheria was ca 88% of that on Salix patch and decreased with increasing patch size, because the differences in stem and leaf architectures and phenology between the two patch-forming species. Moisture and total nitrogen in volcanic deposits were 2-3 times higher in the patches than in bareground. In the patches, low light intensity restricted seed germination, in particular, for the plants characteristic of bareground, e.g., Anaphalis, while high soil moisture increased the survival rates of Calamagrostis. In Gaultheria patches, despite high moisture, the reduced light intensity influenced seed germination and inhibited the establishment of most species. Seedbanks estimated by a lab-experiment indicated that Salix patches trapped more seeds. As a consequence, Salix patches act as facilitator, in particular, for Calamagrostis, by improving moisture and nutrients status of volcanic deposits, moderating light intensity and seed trapping. Deciduous shrub patches, such as Salix reinii, have an improving role in accelerating rates of succession in harsh environments, while evergreen shrub patches slow plant establishment.
  • 五十嵐 八枝子, 岩花 剛, 仙頭 宣幸, 露崎 史朗, 佐藤 利幸
    第四紀研究 = The Quaternary research 42 6 413 - 425 日本第四紀学会 2003年12月01日 [査読有り][通常論文]
  • MIRMANTO Edi, TSUYUZAKI Shiro, KOHYAMA Takashi
    Tropics 12 4 287 - 294 日本熱帯生態学会 2003年 [査読無し][通常論文]
     
    A plot census for trees over 5 cm in diameter at breast height was conducted in tropical wetlands to understand the effects of distance from river and peat depth on the development of communities, using 14 50 m_50 m plots in Central Kalimantan, Indonesia. There are 294 taxa of woody species were recorded. Combretocarpus rotundatus, Palaquium leiocarpum, Stemonurus scorpioides and Tristania whittiana are the common species. In the 14 plots, Stem density and cumulative basal diameter ranged from 1612-3088/ha, and 18.5-44.6 m2//ha, respectively. Species richness (S) ranged from 41 to 87. Diversity index (H') and evenness (J') varied from 1.29 to 1.68 and 0.771 to 0.910, respectively. Stem density was positively related to distance from river but not to peat depth. Geographical differences were also related to the stem density. H' was related to distance from river, but S and J' were not explained by any environmental factors examined. Plot distribution patterns were examined by detrended canonical correspondence analysis (DCCA). DCCA ordination indicated that distance from river, and hence the intensity and/or frequency of flooding more adequately explained plant community distribution patterns than peat depth. Geographical differences also significantly affected the distribution patterns. Therefore, the distance from river is a suitable parameter to use to investigate plant community distribution in tropical wetland forests, even if peat thickness differs greatly.
  • JH Titus, S Tsuyuzaki
    ECOLOGICAL RESEARCH 18 1 91 - 98 2003年01月 [査読有り][通常論文]
     
    On Mount Koma's volcanically devastated summit six common plant species colonized 12 microsite types differentially. Flat sites covered 65%, rills and gullies 16% and biotic sites 13% of the study area. Most species preferred sites near rocks and avoided flat and biotic microsites. Polygonum and Salix preferred gully bottoms and edges. Polygonum and Salix seedlings avoided flat areas and Polygonum seedlings strongly colonized gullies. Carex oxyandra seedlings preferred Salix patches. The distributions of seedlings and adult plants were correlated. Biotic microsites supported the largest Carex individuals, rills supported the largest Agrostis individuals and the largest Salix individuals were in gully bottoms and flats.
  • JH Titus, S Tsuyuzaki
    PLANT ECOLOGY 169 2 307 - 315 2003年 [査読有り][通常論文]
     
    The slopes of Mt. Koma in Japan are undergoing primary succession as a result of a 1929 eruption. Understory vegetation below a non-native invasive tree species, Larix kaempferi, a native tree, Betula ermanii, and in the open were compared to determine if the non-native tree species was influencing species composition. Larix canopies are significantly larger than Betula canopies. Vegetation under Larix canopies had significantly greater richness and diversity than vegetation in the open, vegetation under Betula was intermediate but was significantly greater than the open in diversity. Vegetation cover was highest under Betula and significantly lower in the open. Larix canopy size was positively correlated with size and number of Salix reinii shrubs. Betula canopy size was positively correlated with size but not with number of Salix reinii shrubs. Species assemblages in the three sites are slightly different as shown by DCA. Due to the limited species pool on Mt. Koma the greatest possible extent of differences between the three microsites is not large. At this point Larix certainly appears to be accelerating succession for the non-tree species. If Larix persists on the slopes then succession would be permanently deflected towards a Larix forest. This would be a case of succession being deflected towards dominance by the introduced species.
  • JH Titus, S Tsuyuzaki
    MYCORRHIZA 12 6 271 - 275 2002年12月 [査読有り][通常論文]
     
    Mycorrhizae occur in most terrestrial ecosystems and are crucial to understanding community structure and function. However, their role in primary succession is poorly understood. This study examined the mycorrhizal colonization of six plant species in relation to microsite types on recent volcanic substrates on the summit of Mt. Koma, Hokkaido, Japan. The six microsites were flat, rill, near rock, Carex tussock, Polygonum patch and Salix patch. Carex oxyandra was nonmycorrhizal and Agrostis scabra and Campanula lasiocarpa were arbuscular mycorrhizal (AM) at all microsites examined. Agrostis AM colonization levels did not differ across microsites. Near rock Campanula roots contained significantly more hyphae than at flat and Polygonum patch microsites, and rill and Carex tussock Campanula more arbuscules than at Polygonum patches. Penstemon frutescens was found to be facultatively mycotrophic with AM colonization occurring in roots of Penstemon growing in Carex tussocks, Polygonum patches and near rocks. Polygonum weyrichii was found to be ectomycorrhizal. Polygonum located in rills and in Polygonum and Salix patches were more colonized than Polygonum in Carex patches. Salix reinii was heavily ectomycorrhizal.
  • S Tsuyuzaki
    BIOLOGICAL CONSERVATION 108 2 239 - 246 2002年12月 [査読有り][通常論文]
     
    The Japanese montane zones are usually covered with well-developed forests, and most ski resorts are constructed there. Therefore, the construction of skislopes requires the destruction of forest ecosystems. To detect vegetation development patterns on skislopes, I assessed vegetation on seven skislopes in the lowland of Hokkaido Island, Japan, using 155 2 m x 2 in plots. The surrounding vegetation was mostly consisted of broad-leaved forests with a floor of dwarf bamboo, Sasa senanensis. The skislopes were established 5-28 years before the surveys by scraping off the topsoil and subsequent artificial seeding. The data of vegetation analyzed by TWINSPAN resulted in six different grassland types: (A) Miscanthus sinensis-Hypochaeris radicata, (B) introduced herbs with low richness, (C) introduced herbs, (D) Artemisia montana, (E) M. sinensis Pueraria lobata-A. montana, and (F) Solidago gigantea var. leiophylla. H. radicata and S. gigantea var. leiophylla were alien species. Vegetation dominated by introduced grasses for erosion control, such as Dactylis glomerata and Poa pratensis, should be initial vegetation on the skislopes. Most tree pioneer species established in the vegetation type A, that was most natural vegetation in the skislopes. Type A seemed to proceed from types B and C, and species richness was the highest. Therefore, this type should be preferable for the management and restoration of skislope vegetation. Type D established on newer skislopes, while types E and F established on older skislopes. Results including detrended correspondence analysis suggested that those vegetation types D-F proceeded to distorted succession, i.e. biological invasion changed native successional sere. Based on these results, I recommended that the restriction of alien invasion and careful monitoring on M. sinensis grasslands are required to restore the natural vegetation. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • S Tsuyuzaki, M Goto
    AMERICAN JOURNAL OF BOTANY 88 10 1813 - 1817 2001年10月 [査読有り][通常論文]
     
    The topsoil that contained the seed bank became buried under thick tephra after the eruptions of Mount Usu during 1977 and 1978. To determine the seed bank potential of the topsoil 20 yr after the eruptions, i.e., in 1998. 408 100-cm(3) samples were excavated under 115-185 cm of volcanic deposits. The topsoil was collected at 10-cm intervals along the horizontal scale and was divided into a 0-5 cm deep upper layer and a 5-10 cm deep lower layer. The seed bank was estimated by both the germination (GM) and flotation (FM) methods. In total, 23 species with an average seed density of 1317 seeds/m(2) were identified by GM, and 30 species with a density of 2986 seeds/m(2) were extracted by FM. The dominant species was Rumex obtusifolius, and perennial herbs. such as Carex oxyandra, Viola grypoceras, and Poa pratensis, were common. For nine species this study provided the first records for field seed longevity > 20 yr. The seed density in the upper layer was double that in the lower layer, and the horizontal distribution was heterogeneous even at 10-cm intervals, We concluded that the seed bank has retained the original structure of the seed bank under the tephra and will persist longer with soil water content between 20 and 40%, no light, and low temperature fluctuations (+/-0.17 degreesC of standard deviation in a day).
  • M Haruki, S Tsuyuzaki
    ECOLOGICAL RESEARCH 16 3 451 - 457 2001年09月 [査読有り][通常論文]
     
    The establishment patterns of woody plants were investigated on the volcano Usu, 9 years after the 1977-1978 eruptions. The former vegetation was covered by a 1-3 m thick volcanic deposit. Trees producing wind-dispersed seeds capable of long distance dispersal, such as Populas maximowiozii Betula platyphylla var. japonica, Salix hultenii var. angustifolia, and Salix sachalinensis, were dominant. Most trees were only 2-4 years old in 1986, suggesting that chances for seedling establishment were restricted. The tree heights did not differ significantly among the species, while lengths of annual shoots differed due to herbivore preferences. Trees were established at higher densities on gravel-dominated pumice surfaces than on fine-textured surfaces. Tree density was not greatly affected by the nutrient content of deposits. From 1987 to 1990, tree height increments did not differ between the gravel and non-gravel areas. Ground surface texture is an important factor in determining seedling establishment in the early stages of volcanic succession, and nutrient status is unimportant.
  • S Tsuyuzaki, T Nakano, S Kuniyoshi, M Fukuda
    SOIL BIOLOGY & BIOCHEMISTRY 33 10 1419 - 1423 2001年08月 [査読無し][通常論文]
     
    The relationships between vegetation types and methane flux were evaluated in north-eastern Siberia in the summer of 1995. Based on 71 50 X 50-cm plots, the vegetation was divided into three types by TWINSPAN cluster analysis: (1) Eriophorum grassland where species richness was high and moss well-established (Eriophorum grassland), (2) horsetail grassland with moss cover and (3) Carex grassland without moss. Vascular plant cover in all vegetation types was less than 50%. The methane flux was measured by a static chamber method. Horsetail grassland emitted the highest amount of methane, 165.5 mg CH4/m(2)/d, while diverse-sedge grassland emitted less methane, i.e., - 1.9 mg CH4/m(2)/d. Methane flux positively increased with electric conductivity (EC), water depth, thaw depth, and soil humidity. Of those, EC was strongly correlated to methane emission (Spearman's rank correlation, r(2) = 0.630). The difference in methane flux between horsetail grassland and sedge-dominated grassland suggested that the morphological characteristics of vascular plants were important on methane transport, probably because vascular plants, such as horsetail, that developed aerenchyma and intercellular gas space promoted methane transport from soil to air while mosses do not. (C) 2001 Elsevier Science Ltd. All rights reserved.
  • 露崎史朗
    日本生態学会誌 51 1 13 - 22 2001年 [査読有り][通常論文]
  • S Tsuyuzaki
    JOURNAL OF PLANT RESEARCH 113 1112 415 - 418 2000年12月 [査読有り][通常論文]
     
    In this report, the author suggests that the number of veins (NV) is useful to estimate leaf maturation for a tropical fern Pteris mutilata, as has been established in ferns of cool temperate regions. NV expressed developmental stages better than any other leaf size parameters, such as blade length, blade width, stipe length, and total length (blade + stipe length). The leaf shape became more oblong and/or slender after the plant matured, which could be measured by two shape parameters, (blade width)/(total length) and (blade width)/(blade length). Principal component analysis using all the morphological parameters showed that NV is categorized into size parameters, although NV has been considered to differ somehow from the other size parameters. Thus NV represents one of the size parameters that is the most appropriate to estimate leaf maturation.
  • S Tsuyuzaki, T Ishizaki, T Sato
    ECOLOGICAL RESEARCH 14 4 385 - 391 1999年12月 [査読有り][通常論文]
     
    Vegetation structure was surveyed in gullies developed by the melting of ice wedges along the Kolyma River, northern Siberia, using 72 50 x 50 cm plots. The mean total plant cover was approximately 50% on gley soils, which were only distributed in the gullies. Based on TWINSPAN cluster analysis, four vegetation types were recognized: (i) Agrostis purpurascens grassland with Ceratodon purpureus moss carpet; (ii) Matraicaria mataricarioides forbland; (iii) Chamaenerium angustifolium and M. matricarioides forbland; and (iv) Descurainia sophia grassland. Species that produce seeds capable of long-distance dispersal established well. Of the environmental factors surveyed, the gully scales (height and width) and elevational difference within a plot were primarily related to the vegetation development. The gully height was correlated with soil pH and compaction that might be related to intensities of ground surface disturbances. Agrostis purpurascens established in large gullies, while Equisetum arvense and Salix alaxensis established in small gullies. Soil compaction was also related to the vegetation establishment patterns (e.g. Rumex sibirica did not establish on hard soils). We concluded that the gully scales primarily determine soil conditions, including ground surface instability as a function of slope and soil compaction, and subsequent community structure.
  • 露崎 史朗
    日本生態学会誌 49 3 265 - 268 日本生態学会 1999年12月 [査読有り][通常論文]
  • Jonathan H. Titus, Shiro Tsuyuzaki
    Arctic, Antarctic, and Alpine Research 31 3 283 - 292 1999年 [査読有り][通常論文]
     
    Ski slope vegetation on Mount Hood, Oregon, U.S.A. was surveyed to assess vegetation that has developed under a constant disturbance regime and the environmental factors that are important in structuring the vegetation. Ski runs extend from 1200 to 2200 m on the south face of Mount Hood. TWINSPAN distinguished 17 plant communities including 4 above treeline and 13 below treeline 3 of the latter also occur in the forest adjacent to the ski runs. Elevation, which is correlated to temperature, precipitation, depth of snowpack, and timing of snow melt, is the most important variable structuring the vegetation. Soil texture is also important. Distance to the forest boundary influences the vegetation only at lower elevations. Most of the slopes we examined were thickly vegetated, except above treeline where vegetation is typically sparse. Non-native species were detected only at the lowest elevations and were infrequently dominant. Non-native species cover and richness were correlated with percent bare area. Relative to ski runs in other areas, those on Mount Hood have little non-native species invasion, probably due to the harsh conditions prevalent on the ski runs and to a relative lack of bare areas, which occupy 17% of the runs below treeline. The relative scarcity of bare areas may be a result of the relatively great age of the ski runs (64 yr). Above treeline there was no detectable difference in vegetative composition on and off the ski run, probably due to extensive trampling of the vegetation in the summer.
  • Toshihiro Kondo, Shiro Tsuyuzaki
    Diversity and Distributions 5 5 223 - 233 1999年 [査読有り][通常論文]
     
    The 1929 eruption of Mount Koma (1140 m in altitude) completely deforested the vegetation on the summit area of the volcano. An alien species of larch, Larix kaempferi (= L. leptolepis) was planted on the lower slopes of the volcano between 1953 and 1963, but since then has become abundant on the summit. To determine the regeneration patterns of the larch, we measured stem densities on aerial photographs taken in 1963, 1973 and 1994, and in the field during 1996. Larix kaempferi stems with crown diameters > 2 m were mapped on aerial photographs divided into 1083 100 m x 100 m grids. Stem densities on the summit increased from 0.8/ha in 1963, to 14.1/ha in 1994. Willows and birches also established there but did not grow as large as the larch. All these species are wind dispersed, and larch densities were higher in areas closer to the plantations, suggesting that wind intensity and direction determined seed migration. Four environmental factors - slope gradient, direction, elevation, and distance from the plantations in each grid were correlated with larch stem densities. Multiple regression showed that establishment patterns of L. kaempferi in the early stages were mainly related to distance from seed source (the plantations). Later, geographical disturbances and/or physiological stresses became more important. Density effects on tree invasion have been weak until now. We concluded that revegetation primarily depends on the chance of seed immigration, and that the latches may be an earlier successional species than any other native tree species.
  • JH Titus, S Tsuyuzaki
    ECOLOGICAL RESEARCH 13 2 97 - 104 1998年08月 [査読有り][通常論文]
     
    Ski slope vegetation at Snoqualmie Pass in Washington State, USA, was sun eyed in order to identify community types and to compare it with vegetation development patterns in Japan. Ski slopes in Japan, most of which were constructed after 1960, underwent heavy land recontouring, while those at Snoqualmie Pass were constructed before 1950 with less modification. Three points apply to Japanese ski slope vegetation and differentiate these slopes from those at Snoqualmie Pass: (i) grasslands of introduced species are widespread and persistent; (ii) unvegetated patches are uncommon; and (iii) wetland vegetation has developed. These differences are mainly derived from the intensity of human impact, history of the slope and its scale: namely, ski slopes in Washington are older and larger than those in Japan. Ski slope vegetation in Washington was primarily differentiated by a soil moisture gradient. The large size of Washington ski slopes permitted the inclusion and development of wetland habitats, whereas most ski slopes in Japan are constructed on ridges and do not contain wetlands. Most introduced species in Japan are eliminated soon after seeding. In contrast, the long-term management of ski slopes decreased soil erosion and/or unvegetated patches in Washington and created relatively permanent grasslands composed of introduced species. Tsuga heterophylla and Abies amabilis were found established on the ski slopes in Washington, whereas in Japan the pioneer tree species are shade-intolerant broadleaved species. These differences may be a result of the different disturbance histories of ski slopes in the two countries. In addition, along with the conifers, early successional forbs such as Anaphalis margaritacea and Epilobium angustifolium are well established on Washington ski slopes. Results show that disturbances created by ski slope development greatly affect the vegetation, even on older, less heavily impacted ski slopes.
  • M Tu, JH Titus, S Tsuyuzaki, R del Moral
    FOLIA GEOBOTANICA 33 1 3 - 16 1998年 [査読有り][通常論文]
     
    The 1980 eruption of Mount St. Helens deposited new substrates upon which wetlands are now developing. We collected soil from five wetlands south of Spirit Lake, Mount St. Helens, Washington, to examine the seed banks. Seedling emergence density in the top 5 cm was highly variable, and ranged from (mean +/- s.d.) 15,700 +/- 15,200 to 38,000 +/- 31,500 per m(2.). Seedling emergence from soil at 5 to 10 cm depth varied from 800 +/- 600 to 18,000 +/- 24,800 per m(2), and averaged 1/3 as many seeds as the surface. The high proportion of buried seeds may be due to continuing deposition of upland sediments. We identified 17 taxa from the wetland soil samples with Epilobium ciliatum, Juncus bufonias, Agrostis exarata and Juncus ensifolius being the dominant species. Wetland vegetation was dominated by Equisetum arvense, Salix sitchensis, Typha latifolia and the four dominant species in the seed bank. Correlations between vegetation and seed bank were not significant for four of the five wetlands, and the dominance by Typha latifolia in two wetlands contributed to the low correlations. Thus, vegetation of these early successional wetlands generally was not similar to seed bank composition. Canonical correspondence analysis was used to relate soil parameters to vegetation and seed bank data. The vegetation was correlated primarily with soil particle size and secondarily to water temperature, while the seed bank was correlated to pH, texture and temperature.
  • TAGUIAM Carmela G, 露崎 史朗
    Tropics 7 3 271 - 284 日本熱帯生態学会 1998年 [査読有り][通常論文]
     
    Agroforestry is the favored farming system farmers adopt in Bagong Silang, Makiling Forest Reserve, Philippines. It is a farming system whose origin can be traced from kaingin (swiddening), a fundamental form of agroforestry, handed down by the first batch of farmers to the present generation of farmers. Agroforestry is recognized as an age-old tool in the protection and stabilization of the ecosystem, at the same time it provides a stable source of income and basic materials to the rural folks. However, farmers in Bagong Silang refused to associate their farming system to agroforestry. From the farmers' perspective, agroforestry means reforestation that involves the sole planting of forest trees. Thus, there is a need to strengthen the dissemination of basic information on agroforestry as a farming system and as a conservation tool in order to protect the Reserve from other forms of human activity. Other sociological factors determined to influence the adoption of agroforestry include beliefs and practices, migration pattern, place of origin, occupation and income.
  • Shiro Tsuyuzaki
    Journal of Vegetation Science 8 3 353 - 360 1997年 [査読有り][通常論文]
     
    Wetland vegetation developed in the crater of Mount Usu, northern Japan, soon after the 1977-1978 eruptions which destroyed the vegetation. The cover of each species was measured in 1994 in 118 50 cm x 50 cm plots situated in transects and related to environmental factors (elevation, water depth, soil texture, soil compaction, soil organic matter, and soil pH) to clarify vegetation development. Five vegetation types were recognized dominated by Eleocharis kamtschatica, Equisetum arvense, Lythrum salicaria. Juncus fauriensis and Phragmites australis respectively. Sedge/grass marsh and reed swamp dominated deep-water sites willow swamp and wet meadow vegetation characterized shallow-water sites, indicating that vegetation zonation developed soon after the eruption. Since those wetland plants were derived neither from seed banks nor from vegetative propagules, they had to immigrate from outside the summit areas. However, except for willows, most species lack the ability for long-distance dispersal. Late successional species, such as P. australis established in the early stages of the primary succession. The water depth varied by 27.5 cm among the plots. Coarse soil particles accumulated, and pH (5.22 - 6.55) was low on the elevated sites. Organic matter ranged from 2.8 % to 19.1 % and was high on the elevated sites. Water depth was responsible for the establishment of large-scale vegetation patterns, while edaphic factors, i.e. soil compaction, pH, and organic matter, were determinants of small-scale vegetation patterns. Among the edaphic factors, soil compaction appeared to have a strong influence on vegetation development.
  • Shiro Tsuyuzaki, Jonathan H. Titus, Roger Del Moral
    Journal of Vegetation Science 8 5 727 - 734 1997年 [査読有り][通常論文]
     
    We examined the factors that control seedling establishment on barren substrates on the pyroclastic flows from Mount St. Helens. From June to September in 1993, we monitored seedling and microhabitat changes in 240 20 cm x 20 cm quadrats on the Pumice Plain. Seedlings emerged in 104 quadrats (43.3 %). The most abundant species were A naphalis margaritacea, Hypochaeris radicata, Lupinus lepidus and Epilobium angustifolium. Measured site characteristics included topography, particle size distribution, ground surface movements, soil water content, organic matter, pH, and presence or absence of dead lupines. Quadrats with seedlings had higher cover of dead lupines, higher amount of rock and gravel substrate, and a greater cover of rills. More seedlings emerged where eroded material accumulated. Compared to coarse-textured surfaces, silt surfaces had higher organic matter, held more water, and showed higher pH. However, seedlings became established more frequently on coarse-textured surfaces. In greenhouse experiments, a higher percentage of Hypochaeris seeds germinated on silt than on sand or gravel. The germination of Anaphalis and Epilobium did not differ with soil texture, but was higher at higher moisture levels. Seedling colonization is more dependent on ground surface microtopography, particle size, and ground movement than on the chemical status of these volcanic deposits.
  • キク科属名HypochoerisはHypochaerisの誤りである
    露崎史朗, 北山太樹
    植物研究雑誌 71 302 - 303 1996年 [査読有り][通常論文]
  • Shiro Tsuyuzaki
    Vegetatio 122 2 151 - 156 1996年 [査読有り][通常論文]
     
    To evaluate alpha diversities, various variables such as density, cover, volume, and weight have been used. However, density is often a distinct variable from the remaining three. To clarify differences in diversity measured by those two kinds of variables, the data collected in fourteen 2 x 5 m permanently-marked plots on Mount Usu, Japan, which erupted during 1977 and 1978 in growing seasons from 1983 to 1989 was analyzed, using Shannon's species diversity (H′) that is represented as a result of combination of species richness and evenness (J′). H′ and J′ were evaluated by density (density H′ and J′) and cover (cover H′ and J′). Cover H′ and J′ were significantly lower than density H′ and J′, indicating that cover H′ has different characteristics from density H′. Those differences are due to differences in evenness, because species richness is the same. The rank orders of species density are different from those of cover. The predominance of a few perennial herbs greatly decreases cover evenness, while seedling establishment success influences density evenness. Therefore, I propose that, during the early stages of succession on harsh environments such as volcanoes, density diversity represents seedling establishment success rate while cover diversity expresses vegetative reproduction success rate. © 1996 Kluwer Academic Publishers.
  • Shiro Tsuyuzaki, Masahiro Haruki
    Vegetatio 126 2 191 - 198 1996年 [査読有り][通常論文]
     
    Although the summit of Mount Usu was deforested by the 1977-78 eruptions, vegetative regeneration on the caldera rim was rapid due to the erosion of thick volcanic deposits by snow and rain. To obtain the mechanisms underlying regeneration patterns after the eruptions, we monitored the growth of permanently-marked stems from 1983 to 1990. Regeneration was from resprouting-branches buried in the volcanic deposits on the caldera rim, while on the crater basin, where thick volcanic deposits accumulated, regeneration was from seedlings. The seedling regeneration lagged approximately 3 years behind vegetative regeneration. Stem densities averaged 14,000 ha-1 in the vegetatively-regenerated community on the caldera rim, and 28,000 ha-1 in the seedling regeneration on the crater basin. Populus maximowiczii accounted for ca. 75% of total stems on the caldera rim, while P. maximowiczii accounted for ca. 30% on the crater basin where Salix integra and Betula platyphylla var. japonica were also common. In both stands, immigration and mortality rates were very low. The growth of vegetatively regenerated stems expressed as stem height and diameter was significantly faster than that of stems grown from seedlings. Herbivory damage on the terminal shoots of tall stems was restricted on the caldera rim and was restricted for B. platyphylla var. japonica on the creater basin, perhaps due to fast growth supporting herbivore avoidance or low palatability. Height growth was restricted when neighbors established in close proximity, especially in the seedling-regenerated forest. The results suggest that vegetative regeneration is rapid due to three mechanisms: 1) faster plant growth 2) herbivore avoidance and 3) decreased interference by neighboring.
  • Shiro Tsuyuzaki, Fusayuki Kanda
    American Journal of Botany 83 11 1422 - 1428 1996年 [査読有り][通常論文]
     
    To compare revegetation patterns between native and exotic species on abandoned pastures in northern Japan, we surveyed the vegetation structure and the seedbank using a flotation technique in 140 1 x 1 m plots. Previously introduced grasses such as Poa pratensis, Phleum pratense, and Dactylis glomerata were abundant 20 yr after the pasture abandonment, while Sasa senanensis, native shrub species, regenerated from propagation that had spread from the surrounding forests. S. senanensis shrublands and P. pratensis/P. pratense grasslands established on deep soils while D. glomerata grasslands established on shallow soils. Trees rarely became established on abandoned pastures. The seed density in the seedbank, representing 19 species, ranged from 542 to 2957 seeds/m2. The dominant species in the vegetation (P. pratensis, Trifolium repens, and Rumex acetosella) were also common in the seedbank, whereas Cerastium holosteoides var. angustifolium, Chenopodium album var. centrorubrum, and Erigeron canadensis were widespread in the seedbank but did not occur in the extant vegetation. S. senanensis regenerated by vegetative propagation, and P. pratensis and P. pratense developed a seedbank. We concluded that for native species, particularly S. senanensis, vegetative reproduction has an important role on revegetation rather than regeneration from the seedbank, and the dwarf bamboo may be a keystone species in the ecosystems.
  • S Tsuyuzaki, JH Titus
    AMERICAN MIDLAND NATURALIST 135 1 172 - 177 1996年01月 [査読有り][通常論文]
     
    We surveyed 28 pairs of 2 X 5 m plots located inside and outside of six gullies on the Pumice Plains of Mount St. Helens to study the effects of gully development on vegetation. These gullies are the result of the movement of volcanic deposits laid down by the eruption in 1980. Surveyed gullies were more than 5.0 m wide, 1.5 m deep and 200 m long. Mean cover of vegetation inside and outside the gullies was, respectively, 1.5% and 8.0%. Anaphalis margaritacea, Carer mertensii and Penstemon cardwellii were common both inside and outside the gullies, but cover and frequency of each species were significantly lower inside the gullies than outside. Lupinus lepidus was dominant outside gullies with a mean cover of 5.0%, but only 0.3% inside gullies. These results suggest that gully develop ment strongly restricts cover development of most species, in particular L. lepidus. Total cover and species richness were significantly lower inside gullies, but species diversity was net significantly different. Because of the reduction of L. lepidus cover inside gullies, evenness was higher and species diversity did not differ between inside and outside the gullies.
  • S TSUYUZAKI
    ENVIRONMENTAL MANAGEMENT 19 5 773 - 777 1995年09月 [査読有り][通常論文]
     
    To determine the status of the vegetation of ski slopes in northeastern-central Honshu, Japan, 94 plots (2 x 2 m) were set up on five ski areas (101-520 m elevation) which were established between 1945 and 1985 by forest clear-cutting, land modification, and seeding. Six vegetation types were recognized: five grasslands dominated by Digitaria adscendens, Miscanthus sinensis, Zoysia japonica, Festuca rubra, and Pteridium aquilinum var. latiusculum, respectively, and bare areas of very low to no vegetation cover. Of the dominant species, F. rubra is the only introduced species; it does not, however, appear to persist. After the introduced grassland declines, M. sinensis or annual grasslands develop. Native plants, especially woody species, can establish in M. sinensis grassland but do not establish in the other grasslands. It is concluded that the introduction of exotic species is inappropriate to maintain ski slope vegetation, and the development of M. sinensis grassland is desirable to promote natural revegetation.
  • S TSUYUZAKI
    JOURNAL OF PLANT RESEARCH 108 1090 241 - 248 1995年06月 [査読有り][通常論文]
     
    Permanently plots were monitored from 1983 to the present on Mount Usu after the eruptions of 1977-78 which destroyed the pre-eruption vegetation by 1-3 m thick accumulations of ash and pumice in order to clarify the processes and mechanisms of succession. Until now, 163 species were recorded in the summit area. Most of these species were derived from vegetative reproduction throughout the volcanic deposits. Vegetative reproduction plays a major role on increases in cover. Although long-distance seed-dispersal species could immigrate to the crater basin, their cover increase was slow. Seedbank species only established in gullies where the original topsoil was exposed by erosion. Most annuals were supplied by the seedbank in the original topsoil and woody species originated via immigration, suggesting that the source greatly determines the species composition of establishing vegetation. Annual seedlings showed low survival, while overwintering perennial seedlings steadily established. Ground surface movements strongly restricted increases in plant cover and the distance from source vegetation was the principal determinant of plant density. Due to differences in disturbance intensity, successional rates were higher in the stable substrates outside gullies and lower on the exposed original topsoil in some gullies.
  • Shiro Tsuyuzaki, Roger del Moral
    Journal of Vegetation Science 6 4 517 - 522 1995年 [査読有り][通常論文]
     
    Abstract. We predicted that plants that can establish on volcanic soils with similar disturbance histories will have similar growth characteristics. We tested this prediction by a multivariate analysis of 27 traits of 84 species found six years after an eruption on Mount St. Helens, Washington State, USA, and Mount Usu, Hokkaido, Japan. These traits include vegetative, life‐history, phenological and seed‐biology characteristics. Cluster analysis revealed five species groups: annual herbs, perennial forbs, graminoids, shrubs and trees. Each group has distinct vegetative, life‐history, and seed‐biology traits. Except for shrubs, which were lacking on Mount Usu, both floras were well represented in each group. On intensely disturbed sites on both volcanoes, perennial forbs, whose development is dependent primarily on well‐developed below‐ground organs and wind‐dispersal, expanded their cover more rapidly than did graminoids. These graminoids generally produce gravity‐dispersed seeds and have close‐set rhizomes and/or shoots. These results suggest that species that can establish during the early stages of succession on each volcano have similar vegetative, life‐history, and seed‐biology traits. 1995 IAVS ‐ the International Association of Vegetation Science
  • 露崎 史朗
    日本生態学会誌 44 3 315 - 320 日本生態学会 1994年12月 [査読有り][通常論文]
     
    I studied the structure of a thinned Larix olgensis HENRY forest located on Sandaohu peatland in northeastern China. In the peatland where peat accumulation was less than 20 cm, three tree species, L. olgensis, Betula platyphylla and Populus koreana, occurred. Forest did not develop at sites where peat accumulation exceeded 40 cm. No tree seedlings were present on the forest floor. Forty-one L. olgensis stems were established in a 15 m×15 m plot. The age of L. olgensis ranged from 20 to 29 (averaged 30.9) years. Height and DBH, varied from 1.8 to 14.9 m, and from 0.9 to 22.3 cm, respectively. The thinning, which had been conducted 10-18 years previously, had reduced tree density by 1/3 and created crown gaps. At the time of observation, there were 32% gaps and 12% tree crown overlaps, both of which were also considered to have been created by thinning. However, the thinning had little influence on stem width growth. These results suggested that the growth and seedling establishment of L. olgensis are little affected by light conditions. Soil status such as nutrient availability is considered to be more important.
  • S TSUYUZAKI, R DEMORAL
    ECOLOGICAL RESEARCH 9 2 143 - 150 1994年08月 [査読有り][通常論文]
     
    Canonical correspondence analysis (CCA) was applied to explore revegetation patterns during early succession on Mt Usu. Vegetation was buried by deposits of ash and pumice from 1 to 3 m in depth from the 1977-78 eruptions. Three habitats were selected: tephra, tephra in gully and original surface. Plant density and plant cover data were analyzed separately. Environmental factors consisted of five quantitative variables (organic matter, elevation, distance from colonizing source, erosion and deposition of volcanic deposits) and three nominal variables (habitat types: tephra, tephra in gully and original surface). Canonical correspondence analysis showed that the original surface played a special role in vegetation development because the old topsoil supplied both nutrients and seed-bank species. The CCA also suggested that the environmental factors that influence plant density and cover differ. Distance from colonizing source affected plant density while erosion affected cover. Using CCA, factors could be distinguished that influenced seedling establishment from vegetation expansion and vegetation recovery dynamics could also be more clearly interpreted.
  • Shiro Tsuyuzaki
    Environmental Conservation 21 2 121 - 125 1994年 [査読有り][通常論文]
     
    Ski slopes are commonly established following clearcutting of areas of well-developed forests, scraping off the surface soil, and seeding the entire ground-surface, as forests widely remain in mountainous regions where skiing is developed in Japan. The ski slopes are then sown with seeds of exotic plants in an attempt to prevent soil erosion. However, many bare areas remain, or develop, on ski slopes. Due to this landscape fragmentation, not only deterioration of Nature but also environmental problems develop, including those of water, garbage, and traffic, pollution. The ski-resort concentration occurs mainly in regions of high-quality landscape around urbanized areas, and derives mostly from economic benefits. Yet any regulation of ski-resort construction has unfortunately been delayed. Areas where ski-resorts have been concentrated have a high risk of damage, and further studies of the situation are overdue. We should reconsider the construction, enlargement, and distribution patterns, of skiresorts, and any further development should be based on sound ecological and conservational knowledge rather than mere transient economic considerations. © 1994, Foundation for Environmental Conservation. All rights reserved.
  • S TSUYUZAKI
    NATURAL AREAS JOURNAL 14 1 59 - 60 1994年01月 [査読有り][通常論文]
  • S. TSUYUZAKI
    Weed Research 34 6 433 - 436 1994年 [査読有り][通常論文]
     
    In this study a flotation method is described which enables the rapid extraction of seeds from soil. Essentially, soil is mixed with 11.0 M K2CO3 and thoroughly dispersed by mechanical stirring for 3–6 min. The dispersed soil samples were delivered to plastic tubes, then centrifuged at more than 4000 g for about 5 min. Buried seeds and lighter organic materials floated in the supernatant and could be removed by filtration, washed and subsequently identified. This method performed reliably using soil samples artificially loaded with white clover and a range of cultivated grass species. In addition, a wide range of weed seeds which differed in size and density were also effectively recovered from a range of soil types from loam to gravel. Extraction rapide de graines à partir du sol par une méthode de flotation Cet article décrit une méthode de flotation qui permet l'extraction rapide de graines à partir du sol. Pour l'essentiel, le sol est mélangé avec du K2CO3 11,0 M et complètement dispersé par agitation mécanique pendant 3 à 6 min. Les échantillons de sol dispersé sont placés dans des tubes en matière plastique et contrifugés à plus d 4000Xg pendant environ 5 min. Les graines enfouies et le matériel organique plus léger flottent dans le surnageant, sont récupérées par filtration, lavées et identifiées. Cette méthode s'est révélée fiable avec des échantillons de sol portant artificiellement de fortes densités de trèfle blanc et une série de graminées cultivées. De plus, de nombreuses graines de mauvaises herbes qui différaient par leur taille et leur densité ont été efficacement récupérées de plusieurs types de sol (limons à graviers). Schnellmethode zur Bestimmung des Samengehalts im Boden durch Abschwemmen Es wird eine Methode beschrieben, mit der Samen aus Boden schnell ausgelesen werden konnen. Bazu wird dem Boden 11,0 M K2CO3 zugesetzt und der Boden 3 bis 6 Min. lang grundlich gemischt. Danach wird das Bodenmaterial in Plastikzylindern bei mehr als 4.000 g 5 Min. lang zentrifugiert. Die im Boden enthaltenen Samen und organisches Material sammeln sich im Uberstand und konnen durch Filtration abgetrennt und nach dem Waschen identifiziert werden. In einem Modellversuch, bei dem Samen von Weiß‐Klee und einer Reihe Graser dem Boden beigemischt worden waren, erwieß sich diese Methode als zuverlassig. Auch andere Samen unterschiedlicher Große und Dichte wurden in verschiedenen Bodenarten von Lehm bis grobem Sand vollstandig wieder aufgefunden. Copyright © 1994, Wiley Blackwell. All rights reserved
  • S TSUYUZAKI, F KANDA, K NARITA
    ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 15 4 461 - 467 1994年 [査読有り][通常論文]
     
    Vegetation status on an abandoned pasture in northern Japan was investigated to obtain the determinants of vegetation development. Ten factors were selected: soil depth down to three horizons, soil texture (relative percentage of silt, sand, and gravel), soil water content, soil organic matter, light intensity at the ground surface, and distance from the forest edge. Above- and below-ground systems of a dwarf bamboo, Sasa senanensis, were also measured. These data were analyzed by canonical correspondence analysis. Previously-introduced grass, i.e., Dactylis glomerata, remained on the abandoned pasture even 20 years after the abandonment of the pasture. While S. senanensis inhabits sites with deep soil by means of vegetative reproduction, mosses establish on sites with shallow soil. Soil depths that permit root expansion seem to be the most important for S. senanensis to elongate roots. Species richness was very low under the canopy of S. senanensis, which strongly intercepts light. Therefore, we conclude that soil depth is the primary determinant of vegetation development.
  • 露崎 史朗
    生物科学 45 4 p177 - 181 日本生物科学者協会 1993年11月 [査読無し][通常論文]
  • S TSUYUZAKI
    BIOLOGICAL CONSERVATION 63 3 255 - 260 1993年 [査読無し][通常論文]
     
    This paper describes the characteristics of the present vegetation on highland ski grounds, predicts its successional sere, and proposes methods for the restoration of natural vegetation. Vegetation data were collected from Nakayama (836 m altitude, 40-ha ski area), Teine Highland (1000 m, 40 ha), and Sapporo International (1100 m, 61 ha) ski grounds located around the city of Sapporo, Hokkaido, northern Japan. These ski areas were established by clearcutting of forest, scraping off the soil surface, and artificial seeding over the whole ground surface at the time of opening. Petasites japonicus var. giganteus was dominant in all three ski grounds. Based on species clustering and quadrat data, including cover, species numbers, life forms, and stem densities, three phases of vegetation establishment were noted: (1) artificially introduced plants gradually declined in cover; (2) three types of native vegetation were then recognized, dominated by P. japonicus var. giganteus, Juncus effusus var. decipiens and Sasa kurilensis; and (3) there was invasion by woody plants consisting of sun trees, e.g. Betula spp. and Salix spp. Based on these vegetational changes, successional seres are suggested, together with problems of vegetation maintenance in highland ski grounds in relation to the establishment of native plants.
  • S TSUYUZAKI
    SEED SCIENCE AND TECHNOLOGY 21 2 479 - 481 1993年 [査読有り][通常論文]
     
    The final germination of seeds immersed in 50% K2CO3 was greatest when soaking time was least. Dry seeds germinated better after immersion in K2CO3 than did pre-imbibed seeds. The implications for seed recovery from soil by flotation in K2CO3 are indicated.
  • S. Tsuyuzaki, T. Tsujii
    Canadian Journal of Botany 70 2310 - 2312 1992年01月01日 [査読無し][通常論文]
     
    While tussocks did not exceed 26 cm in height, the basal area of tussocks continually expanded. Mature tussocks sometimes resulted in aggregation of tussocks. Carex meyeriana rarely developed long horizontal rhizomes and produced shoot rhizomes that led to the development of bell-shaped tussocks as a result of basalt shoot (tiller) development patterns. Equisetum limosum invaded and grew in immature tussocks, while Potentilla anserina and Chamaesium paradoxum invaded tussock summits. -from Authors
  • Shiro Tsuyuzaki
    Advanced Optical Manufacturing and Testing Ii 1992年
  • 露崎史朗
    人間と環境 18 1 1992年
  • 露崎 史朗
    日本生態学会誌 41 2 83 - 91 The Ecological Society of Japan 1991年08月 [査読無し][通常論文]
     
    To obtain characteristics of ski ground vegetation and predict its successional sere, surveys were undertaken on three ski grounds in Hokkaido : Play Bankei (constructed in 1968), Teine Olympia (1971) and Makomanai (1980), whose land surface were modified by heavy human impact, i.e., land cutting, sowing of herbs, and regular bush cutting. Analysis of species composition and clustering revealed vegetation of sites surveyed to be mainly divisible into four vegetation groups as follows : al) grassland of sowed herbs ; a2) Artemisia montana grassland ; b) low-cover grassland ; c) Miscanthus si...
  • S. Tsuyuzaki
    Canadian Journal of Botany 69 2251 - 2256 1991年01月01日 [査読無し][通常論文]
     
    Even after 10 yr burial by 65-140cm volcanic deposits, 16.6% of the seeds, representing 25 species, were viable. Speed volume of most species was less than 2.0 mm3. Smaller seeds had a greater rate of survival than larger seeds; seed survival rates of Poa annua, Rumex obtusifolius, Alopecurus aequalis var. amurensis and Viola grypoceras were positively correlated with thickness of volcanic deposits. -from Author
  • Shiro Tsuyuzaki
    Journal of Vegetation Science 2 3 301 - 306 1991年 [査読無し][通常論文]
     
    To study the rate of revegetation during succession on the volcano Usu, northern Japan, vegetation structure and species composition were monitored from 1984 to 1988 in permanent quadrats near the summit of the volcano, which had been almost completely deforested by 1 to 3 m thick volcanic deposits in 1977–78. Analyses of vegetation structure included species richness, species diversity IT, evenness (J') year‐to‐year changes were quantified using Community Coefficient (CC), and Percentage Similarity (PS). While species turnover rates fluctuated and vegetation cover gradually increased, species richness, diversity and evenness did not fluctuate much. The diversity parameters showed slightly different levels for three habitat types distinguished. CC values comparing subsequent years with the starting year 1984 suggest only minor changes in qualitative species composition PS values decreased more rapidly, indicating larger changes in species cover. A few well‐rooted perennial plants were predominant, therefore, PS decline resulted from dominance‐controlled community structure. PS‐value detected not only habitat difference, but also the rate of the volcanic succession, suggesting that PS is most effective to evaluate successional pace. 1991 IAVS ‐ the International Association of Vegetation Science
  • Shiro Tsuyuzaki, Tatsuichi Tsujii
    Ecological Research 5 2 271 - 276 1990年08月 [査読無し][通常論文]
  • S TSUYUZAKI, S URANO, T TSUJII
    VEGETATIO 88 1 79 - 86 1990年07月 [査読無し][通常論文]
     
    To obtain the characteristics of Chinese alpine grassy marshland, the vegetation of Ruoergai marshland, which is the largest peatland in China, and of neighboring areas was surveyed along mountain slopes in three areas, Ouhailao, Waqie and Kaharqiao. Based on the clustering of 122 1 m × 1 m quadrats surveyed, the vegetation was grouped into 8 types. From bottom to top of mountain slopes, the dominant species, zonally established, were: 1) Carex enervis and Equisetum limosum; 2) Carex meyeriana; 3) Deschampsia caespitosa, Caltha scaposa and Anemone obtusiloba; 4) Koeleria cristata; 5) Kobresia tibetica and Caltha scaposa; 6) Blysmus sinocompressus; 7) Polygonum sphaerostachyum and Trollius ranuncloides; and 8) Ranunculus pedicularis. In this order, species richness increased gradually along the slopes. A principal component analysis demonstrated that water depth partly regulated the establishment of vegetation. The geographical difference of vegetation was also observed, in particular, in Waqie. Likewise, grazing is considered to modify this vegetation. © 1990 Kluwer Academic Publishers.
  • S TSUYUZAKI
    ENVIRONMENTAL MANAGEMENT 14 2 203 - 207 1990年03月 [査読無し][通常論文]
     
    In 1986 and 1987, a study on factors governing revegetation on ski grounds was conducted at Teine ski ground (built in 1971) located near the city of Sapporo in northern Japan. Soil movement, slope gradient, distance from forest edge, vegetation cover, and number of species on the ski ground were examined. Although artificial sowing of exotic plants was undertaken in the whole ground surface at the time of opening, bare land occurred in ca. 50% of surveyed plots and the ski ground was mostly covered with native plants. The number of species was positively correlated to vegetation cover, which was low in the sites where intensive soil erosions occurred in winter. A principal component analysis of plant species distinguished three major groups of factors, i.e., vegetation cover (first axis, contribution rate 30.3%), soil erosion in winter and slope gradient (second, 23.1%), and distance from forest edge (third, 16.3%). The vegetation characteristics on the ski ground were not determined by a single environmental gradient but by the combination of factors described above. In particular, soil movements, which are mostly derived from snowmelt, are considered to be the initiator of vegetation changes. © 1990 Springer-Verlag New York Inc.
  • S TSUYUZAKI
    BOTANICAL MAGAZINE-TOKYO 102 1068 511 - 520 1989年12月 [査読無し][通常論文]
     
    Soon after the 1977-78 eruptions of the volcano Usu, there were created many gullies in which former topsoil, i.e., well-developed soil accumulated before the eruptions, was eroded in the crater basin, whereas the outside of the gully was covered with thick volcanic deposits. The short-dispersal-seed plants were the most abundant in the inside of gully where the former topsoil was exposed, however, they have not immigrated from external environments. The germination tests of the seeds extracted from the former topsoil demonstrated that viable seeds were buried at 1683.3/m2 for 9 years after the eruptions. At least, 12 herbaceous species, e.g., Rumex obtusifolius, Geum macrophyllum var. sachalinense and Poa annua, were derived from the buried seeds in the former topsoil. Their contribution to revegetation was estimated to be 40.0% in the inside of gully where the former topsoil was exposed in 1983, suggesting that buried seeds are one of the most important seed source for revegetation even in the case of a volcano which produced pumice and ash by eruption. © 1989 The Botanical Society of Japan.
  • Shiro Tsuyuzaki
    Ecological Research 4 2 167 - 173 1989年08月 [査読無し][通常論文]
     
    In 1987, a study on buried seed populations was conducted in the crater basin of Mt. Usu, a volcano located in northern Japan, where the vegetation had beeen almost completely destroyed by eruptions in 1977 and 1978. The former vegetation had consisted of grassland and broad-leaved forest. In the areas formerly occupied by this grassland and forest, 2128.0 and 1985.3 seeds per square meter, respectively, were extracted from 12 blocks of the former topsoil using a floattion method. This revealed that many seeds were still viable even after ten years of burial under thick volcanic deposits. The seeds were distributed more in sandy soil than in rocky soil of the former topsoil. Twenty-five species, most of which favored grassland, were detected in both the former grassland and forest. From comparison of α-and β-diversities between the grassland and forest, the structure of the buried seed population was considered likely to have been more diverse in the forest than in the grassland. The determinants of composition of the buried seed populations were discussed with reference to the former vegetation and soil characteristics. © 1989 the Ecological Society of Japan.
  • S. Higashi, S. Tsuyuzaki, M. Ohara, F. Ito
    Oikos 54 389 - 394 1989年01月01日 [査読無し][通常論文]
     
    Trillium tschonoskii is a perennial herb which grows in single-species stands in the cool temperate broad-leaved deciduous woodland of Hokkaido, Japan. Its many-seeded fruit initially falls close to the parent, >50% within 20 cm. Ants, principally Myrmica ruginodis and Aphaenogaster japonica, transport seeds to their nests, a mean distance of 64 cm. The nests are overdispersed and short-lived, and are no richer in N or P than surrounding soils. There are proportionally more older than younger juvenile Trillium plants at distances >60 cm from the nearest parent plant, ie the relatively short-distance dispersal of seeds by ants is sufficient to reduce seedling mortality, by reducing competition between seedlings. -from Authors
  • S. Tsuyuzaki
    American Journal of Botany 76 1468 - 1477 1989年01月01日 [査読無し][通常論文]
     
    Since seedling mortality appeared mostly due to the frequent erosion of the volcanic deposits, ephemeral annuals and well-rooted perennials or woody plants were successful here. The high mortality of seedlings resulted in intensive fluctuation of plant density in all habitats, but owing to the expansion of perennials, once they became established, the plant cover increased from year to year. In particular, Polygonum sachalinense and Petasites japonicus var. giganteus, seeds of which were frequently provided from their community vegetatively recovered on the wall of the caldera rim soon after the eruptions, were remarkably contributive to the revegetation. Perennial plants were derived not only from the seeds but also vegetatively from the old stumps buried in the former topsoil by extending their rhizomes up to the present gound surface. -from Author
  • T SATO, S TSUYUZAKI
    BOTANICAL MAGAZINE-TOKYO 101 1063 267 - 280 1988年09月 [査読無し][通常論文]
     
    Developmental leaf architecture was quantitatively described in terms of measurements of various parameters on leaf blade from different size of sporophytes in Dryopteris monticola, D. tokyoensis and a putative hybrid, D. kominatoensis in the natural site of Hokkaido, to compare the ontogenetic differentiation in foliage structure among allied ferns. The morphological stage of leaf and sporophyte was tentatively quantified by the number of midrib branches of the leaf (NV, number of veins), which exhibited a significant correlation to the leaf-shape complexity from a circle (DI=marginal length/2×(3.14×square)1/2) of leaf blade. D. kominatoensis showed intermediate values between others in following characters; DI increase, maximum NV (also blade length), maximum number of costa branches of pinnae (NVMP), number of costa branches of the lowest pinna (NVLP), difference between NVMP and NVLP (NVMP-NVLP), during heteroblastic leaf development. A larger number of leaves per sporophyte was found in D. kominatoensis than in others. The fertility rate (%) and initiation of fertility (IF) in the relative developmental stage (RDS) of D. kominatoensis shifted to that of D. tokyoensis, while the order of pinnae with NVMP shifted to that of D. monticola. Even in the intermediate characters in D. kominatoensis, slight shifts in characters to those of putative parents were found during heteroblastic leaf development. © 1988 The Botanical Society of Japan.
  • 露崎史朗
    人間と環境 14 1 1988年
  • S TSUYUZAKI
    VEGETATIO 73 1 53 - 58 1987年12月 [査読無し][通常論文]
     
    The vegetation near the summit of the volcano Usu was destroyed during eruptions in 1977 and 1978 by 1-3 m thick layers of volcanic deposits. Thereafter, the vegetation gradually recovered and by 1984 134 plant species were recognized of which 95 species had established by vegetative reproduction, 18 by seed immigration from elsewhere, 5 by artificial introduction for soil erosion control and 17 species from viable seeds buried in the former topsoil. The summit area was still covered by thick layers of volcanic ash, which were however rapidly eroded by rains. Vegetatively reproducing plants such as Petasites japonicus var. giganteus and Polygonum sachalense contribute more effectively to the revegetation process than plants of other types of origin. © 1987 Dr W. Junk Publishers.
  • Kiyoshi Irie, Shiro Tsuyuzaki
    NORTHWEST SCIENCE 81 4 333 - 336 1970年01月 [査読有り][通常論文]
     
    Rodent densities were estimated on Mount Usu, northern Japan, 17 years after the 1977-1978 volcanic eruptions. The summit area was completely deforested by the eruptions, and was covered with thick tephra. When the survey was performed, two plant communities developed. One was a forest dominated by Populus maximowiczii, and another was a grassland with a canopy of the large perennial, Polygonum sachalinense. In each plant community, we estimated the abundance of rodents by Sherman traps. The abundance was 5 Clethrionomys rutocanus bedfordiae/100 traps/night in the grassland, and 0 in the forest. This implied that a generalist, C. rutocanus bedfordiae became established in the grassland, probably because of plant community structure, including litter deposits, rather than food resources. The results compared with those from Mount St. Helens suggested that rodent immigration was greatly determined by the scales of eruptions and recovery patterns of plant communities.

MISC

  • 佐藤利幸, 露崎史朗, 吉田静男 長野県植物研究会誌 50 (50) 95‐99 2017年06月 [査読無し][通常論文]
  • Tatsuya I. Saito, Shiro Tsuyuzaki WEED BIOLOGY AND MANAGEMENT 12 (2) 63 -70 2012年06月 [査読無し][通常論文]
     
    In order to explore the methods of recovering native grasses into exotic vegetation, the response of riparian vegetation to the removal of the above-ground shoots and/or litter of Solidago gigantea in a flood plain in Hokkaido, northern Japan, was investigated. The four treatments were: the removal of the above-ground shoots of S. gigantea (A); the removal of the litter of S. gigantea (L); the removal of both the above-ground shoots and litter of S. gigantea (AL); and a control (C). The vegetation cover and S. gigantea cover decreased in the A and AL treatments and increased in the L and C treatments. The understory plant cover increased in the A and AL treatments, but did not change in the L and C treatments. The increases in the understory cover in the A and AL treatments were associated with increases in Phalaris arundinacea. The seedling emergence of P. arundinacea was promoted by AL. In a greenhouse, the S. gigantea litter tended to decrease the seed germination of P. arundinacea. The AL treatment also increased the abundance of the other exotic plant, Solidago altissima. The continuous removal of the above-ground shoots and litter of S. gigantea long term is effective for promoting the recovery and emergence of native riparian grassland vegetation. However, this method also promotes the recovery of other exotics.
  • Appiah Catherine, Shiro Tsuyuzaki, Djietror Jonathan Castel Research Journal of Seed Science 5 (4) 126 -135 2012年 [査読無し][通常論文]
     
    Gold mining occurs in four administrative regions in Ghana with tropical forest cover. Establishment of pioneer vegetation immediately after the mining process is one of the most important rehabilitation practices leading to land reclamation and eventual habitat restoration. A major environmental challenge is that post-mining vegetation sites are prone to wild forest fires that dry up the topsoil and produce a layer of ash on the soil surface. We experimentally tested the effect of post-fire ash and soil moisture on seed germination using the Black-eyed pea (Vigna unguiculata L. Walp) and Egusi (Citrullus colocynthis L.). The study focused on the potential for seed germination in ash under high and low moisture conditions within a greenhouse environment. The viable seeds of the two species were planted at depths 0.0, 0.5 and 1.0 cm. V unguiculata exhibited the highest germination percentage at 0.0 cm in both moisture treatments, but no germination occurred at 0.5 and 1.0 cm depth, showing that germination was considerably inhibited by the ash depth. C. colocynthis showed a comparatively longer dormancy period but with superior germination percentage at all 3 depths under wet conditions. Due to the lower seed germination rate for V. unguiculata under ash, the species might not be easily adapted to ash-covered soils. However, due to significantly higher germination rates under similar conditions, C. colocynthis could potentially be adapted for post-mine vegetation restoration after the occurrence of wild forest fires. © 2012 Academic Journals Inc.
  • <改訂版> 北大エコキャンパス読本-植物編 付・鳥類リスト-
    露崎史朗 北海道大学総合博物館 2005年 [査読無し][通常論文]
  • 西 秀雄, 露崎 史朗 環境教育研究 5 (2) 121 -127 2002年10月 [査読無し][通常論文]
  • 露崎 史朗 日本生態学会誌 52 (1) 140 -140 2002年04月 [査読無し][通常論文]
  • 春木 雅寛, 露崎 史朗 日本生態学会誌 51 (3) 308 -308 2001年12月 [査読無し][通常論文]
  • 露崎 史朗, 長谷 昭, 新沼 寛子, 花田 安司 生物教材 36 (0) 1 -6 2001年03月 [査読無し][通常論文]
  • 露崎 史朗, 長谷 昭 環境教育研究 3 (1) 153 -159 2000年03月 [査読無し][通常論文]
  • 露崎史朗 河川美化・緑化調査研究論文集 6 1998年
  • 露崎 史朗 日本生態学会誌 46 (1) 113 -113 1996年08月 [査読無し][通常論文]
  • 露崎史朗, 神田房行 自然度の高い生態系の保全を考慮した流域管理に関するランドスケープエコロジー的研究 平成6年度 科学技術振興調整費による生活・地域流動研究 1995年
  • 露崎 史朗 日本林学会北海道支部論文集 (37) 39 -41 1989年03月01日
  • 春木 雅寛, 露崎 史朗, 滝川 貞夫 北海道大学農学部演習林研究報告 46 (1) p191 -222 1989年 [査読無し][通常論文]
  • 露崎史朗 日本林学会北海道支部論文集 34 62 -64 1985年
  • 露崎史朗 日本林学会北海道支部論文集 33 89 -91 1984年

書籍等出版物

  • 森林学の百科事典
    露崎史朗 (担当:分担執筆範囲:遷移)
    丸善出版 2021年01月
  • 地球を行く～まだ知らない生きものを調べに, 深海から宇宙まで
    露崎 史朗 (担当:分担執筆範囲:ツンドラファイヤー 永久凍土帯の野火が生態系に与える影響)
    文一総合出版 2018年03月
  • 町村, 尚, 惣田, 訓, 露崎, 史朗, 西田, 修三, 大場, 真, 岸本, 亨, 齊藤, 修, 吉田, 謙太郎, 林, 希一郎, Gibbons, Philip, 松井, 孝典 (担当:分担執筆範囲:第5章. 生態系のダイナミクス (他))
    理工図書 2017年07月 (ISBN: 9784844608646) viii, 163p
  • 河村公隆, 河村 公隆, 大島 慶一郎, 小達 恒夫, 川村 賢二, 佐﨑 元, 杉山 慎, 関 宰, 高橋 晃周, 西岡 純, 原 登志彦, 福井 学, 藤吉 康志, 三寺 史夫, 宮﨑 雄三, 本山 秀明, 渡部 直樹 (担当:分担執筆範囲:北方林における森林火災, 地球環境変動と北方林植生)
    朝倉書店 2016年07月 (ISBN: 425416128X) 432
  • 日本植物学会 (担当:分担執筆範囲:植生遷移)
    丸善出版 2016年06月 (ISBN: 4621300385) 802
  • 生物学辞典
    露崎 史朗 (担当:分担執筆範囲:[ 亜極相, 環境傾度分析, 気候的極相, 極相, 極相種, 極相群集, 極相パターン説, 極相林, 後極相, 湿性遷移, 前極相, 土壌的極相)
    東京化学同人 2010年
  • 重定, 南奈子, 露崎, 史朗, 鈴木, 英治, 上條, 隆志, 奈良, 一秀, 志水, 顕, 原口, 昭, Hotes, Stefan, 神田, 房行, 佐藤, 千尋, 下野, 綾子, 下野, 嘉子, 成田, 憲二, 中坪, 孝之 
    北海道大学出版会 2008年06月 (ISBN: 9784832981850) vi, 258p
  • 重定 南奈子, 露崎 史朗, 神田 房行, 上條 隆志, 佐藤 千尋, 志水 顕, 下野 綾子, 下野 嘉子, 鈴木 英治, 中坪 孝之, 奈良 一秀, 成田 憲二, 原口 昭, HOTES, Stefan, 重定 南奈子, 露崎 史朗 (担当:共編者(共編著者))
    北海道大学図書刊行会 2008年06月 (ISBN: 4832981854) 258
  • 露崎史朗, 北海道大学大学院環境科学院 (担当:分担執筆範囲:地球温暖化にともなう陸上生態系の変化)
    北海道大学出版会 2007年03月 (ISBN: 4832981811) 246
  • 北海道大学大学院環境科学院, 藤原, 正智, 東, 正剛, 長谷部, 文雄, 廣川, 淳, 鈴木, 光次, 豊田, 和弘, 露崎, 史朗 (担当:分担執筆範囲:紫外線と生物)
    北海道大学出版会 2007年03月 (ISBN: 9784832981799) vi, 408p
  • 高橋, 英樹, 露崎, 史朗, 笹, 賀一郎 
    北海道大学総合博物館 2005年03月 52p
  • 露崎, 史朗 
    [北海道大学大学院地球環境科学研究科] 2004年05月 1冊
  • 植物生態学
    露崎 史朗 (担当:分担執筆範囲:第9章 群集・景観パターンと動態)
    朝倉書店 2004年
  • 生態学事典(日本生態学会編)
    露崎 史朗 (担当:分担執筆範囲:ホイッタカー)
    共立出版 2003年
  • 高橋, 英樹, 露崎, 史朗, 笹, 賀一郎, 東, 隆行 
    [北海道大学総合博物館] 2002年 36p

講演・口頭発表等

担当経験のある科目（授業）

  • 自然との共生 SDGs「気候変動に具体的な対策を」を見据えて.北海道大学
  • 生態系論札幌大学
  • 地球環境と生態学北海道大学全学共通科目
  • 生物の多様性北海道大学全学共通科目
  • 流域環境学特論北海道大学大学院環境科学院
  • 自然環境学総論北海道大学大学院環境科学院
  • 生命環境野外実習北海道教育大学
  • 生態学北海道教育大学
  • エコキャンパス-植物編-北海道大学大学全学教育
  • 統合環境調査法実習北海道大学大学院環境科学院
  • 地球温暖化生態学特論北海道大学環境科学院
  • 景観生態学北海道大学環境科学院
  • 人間と環境北海道大学全学教育
  • 自然環境学特論北海道大学大学院環境科学院
  • 環境保全学特論北海道大学大学院環境科学院

所属学協会

  • 米国生態学会   国際植生学会   米国植物学会   英国生態学会   日本植物学会   Botanical Society of Japan   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2022年04月 -2025年03月 
    代表者 : 露崎 史朗
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2021年04月 -2025年03月 
    代表者 : 吉野 邦彦, 露崎 史朗, 串田 圭司
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2016年04月 -2020年03月 
    代表者 : 吉野 邦彦, 露崎 史朗, 串田 圭司
     
    本研究は、生物多様性ホットスポットである釧路湿原の高層湿原を対象にして， ①高層湿原のUAVカラー空中写真による複数年分の詳細植生図作成し経年変化を分析した。②次に複数年次に観測した衛星画像間の画像変化検出を行い、衛星画像上の変化はUAV植生図の変化範囲と対応していることを確認した。③最後にUAV植生図から得られる衛星画像データのピクセルの地上瞬時視野内の植物群落面積率から、植物群落分類のための分光反射特性（分類教師データ）の推定を試み、UAV詳細植生図は分類用参照データとして利用可能であり、ハイパースペクトル衛星リモートセンシングによる湿原全体の詳細植生図作成が可能であると結論付けた。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2012年04月 -2016年03月 
    代表者 : 吉野 邦彦, 神田 房行, 串田 圭司, 足立 泰久, 露崎 史朗
     
    本研究では，釧路湿原保全策の提案を最終目標としてリモートセンシングの最適観測諸元を明らかにした．研究対象地域の高層湿原地域の観測に必要な空間解像度は，独自の精細高層湿原植物群落図を用いた空間解析の結果，高層湿原植物群落の詳細な目視判読のためには1cm程度の地上空間解像度が必要である．植物群落図の作成のためには 10cm～30cm程度の地上解像度が必要であることを明らかにした．最適観測時期は，スゲ類の開花時期の6月下旬から7月中旬であることが明らかになった．しかし，最適観測スペクトル波長帯については明らかに出来なかった．高層湿原の最適観測スペクトル波長帯については,今後，解明する必要がある．
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2009年 -2011年 
    代表者 : 露崎 史朗
     
    多種共存機構であるファシリテーションは、リターと微地形の発達により顕著となるが、定着促進効果が生物学的侵入を促進すれば、生態系回復には負の作用となる。そこで、在来種と外来侵入種が侵入している地域を選び、定着種決定機構に関する比較実験を行った。その結果、リターの発達様式と侵入種の特性との対応関係が最も高く、リター発達は気候に規定されていた。したがって、光・土壌資源や微地形よりもリター発達様式が、より侵入種を規定することが明らかとなった。
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2005年 -2006年 
    代表者 : 露崎 史朗
     
    生物学的侵入(biological invasion)は、非自生生物が人為により移入されその生態系に定着することを指す。特に、撹乱の強い遷移初期において生物学的侵入は顕著であり、その侵入機構には、微地形から景観レベルまで様々なスケールに依存する生物的・非生物的要因が階層的に関与している。本研究は、生物学的侵入が顕著である渡島駒ヶ岳と、それに近接するが生物学的侵入が検出できない有珠山において、比較研究を行ない、スケール依存性環境要因とその相互作用、生物学的侵入種および在来種の生育特性を解明することを目的に行なった。本研究における論文に公表した主な成果は(1)-(4)の通り。1)駒ヶ岳1996年噴火被害地では、有珠山と同様に、有性繁殖よりも栄養繁殖の方が植物群集回復に寄与している。また、様々な生息地において微地形が群集発達に重要である。2)菌根菌の定着は、標高勾配に沿い変化する種が存在する。これまで、内生菌根の発達未報告数種から内生菌根菌定着を確認した。カラマツ成長に対する菌根菌の寄与は低かった。3)埋土種子の生存・発芽特性の時間的変化には、それまで体験していた環境が大きく関与する。4)生物学的侵入種は実生段階において、強風・土壌乾燥・貧栄養などの様々な撹乱やストレスに対応して、在来種よりも高い可塑性を示すことにより生存率が高い。これらの成果をもとに、スケール間の相互作用(トップグウンーボトムアップ効果)の解析を行った。本科研費により購入したウェザーステーションを駒ヶ岳3標高に設置し気象観測を行った。これらの結果を組み合わせ、土壌湿度・微地形等の環境と種子分散・発芽・定着・成長過程でのスケール別の相互作用定量化を完了させた。
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2001年 -2003年 
    代表者 : 露崎 史朗
     
    火山では、裸地化した地域から微量の火山灰堆積が認められる地域まで幅広い環境勾配中で調査が行える。この特色を利用し、微地形および長期動態を考慮に入れ菌根菌-植物間相互作用を定量化することを目的として研究を行った。結果と考察は以下の通り。1.裸地、草地、森林それぞれに調査地を設置した。各群集に設けた調査区内を樹冠下・草地・裸地・コケ優占地(駒ケ岳のみ)、リル発達地といった微地形に区分し(複数カテゴリを含む個所もある)、それらのマクロ-微地形関係における群集動態(特に優占種の動態)を測定した。その結果、木本植物の定着初期には、微地形がもっとも関与することを見出した。また、菌根分布も微地形と関係していることを示した。2.各植物群集における優占種については全種を、各山頂域における種子植物についてはできる限り多くの種(駒ケ岳で約40種)の地下部を採取し、菌根付着量を定量化した。定量化にはメッシュカウント法がよく用いられるが、予備実験から本手法が全種には適応できないことが判明したため、トライパンブルー染色した菌根断片を元にした菌根頻度を測定した。その結果、これまで報告のなかった草本植物数種に外生菌が共生していることを発見した。3.菌根が貧栄養下で植物群集発達に寄与する要因としては、土壌の中でもリンの取り込みを菌根が担うためと言われている。土壌中の、総有機物量、窒素濃度、リン濃度等と菌根菌の分布関係を測定した。その結果、外生菌頻度は標高増加およびそれに伴う噴火降灰物中の窒素減少に伴い増加すること、内生菌頻度は標高軽度とは関係がないことを見出した。4.以上の結果を加え、火山遷移初期動態に関するレビューを行った。特に、駒ケ岳におけるカラマツのように生物的侵入が広範に起こっていることと、その要因としての菌根菌の重要性を指摘した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 1998年 -1999年 
    代表者 : 甲山 隆司, 露崎 史朗
     
    本研究は、北海道山地林に観察される森林タイプ間の明瞭な群集境界に注目して、そのパタンを整理し、景観レベルでのモザイク構造の形成と動態を機能的に説明することを目的として行なった。 知床半島・遠音別岳西斜面のアカエゾマツ林とトドマツ・アカエゾマツ・ダケカンバ混交林の間にみられる明瞭な森林境界について,そのパターンを記述し,動態パラメータと関連づけた。地形・環境条件が連続的であるのに,林木群集が不連続な境界を形成していることを明かにすることができた。森林境界において,アカエゾマツからトドマツに交替するメカニズムを,風雪圧耐性と関連づけるモデルを提案した。渡島駒ケ岳に侵入しつつあるカラマツ林のパターンを航空写真から解析した。 いままで,樹木個体のサイズ分布動態の移流モデルを地理的空間軸に沿って展開したモデルで,群集境界の形成とその動態(環境変化に対して示すタイムラグ)が解析されてきた(Kohyama&Shigesada1995)。森林がギャップ動態とそれに対応したパッチモザイク構造を持つ場合について,このモデルを改訂し,ギャップ動態がある場合でも境界は明瞭であるが,環境変化に対するタイムラグが格段に短くなることを理論的に明かにした。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1996年 -1999年 
    代表者 : 日浦 勉, 石城 謙吉, 甲山 隆司, 東 正剛, 戸田 正憲, 植村 滋, 露崎 史郎, 前川 光司, 青井 俊樹, 大串 隆之, 中野 繁
     
    北海道大学苫小牧演習林において、森林生態系における生物多様性の維持機構を4年間にわたって調べた。この期間に演習林を舞台に我々が出版した学術論文は36編にのぼる(別冊報告書参照)。専門分野の異なる分担者が協力してプロジェクトを行ったため、研究材料は、樹木、昆虫、魚類、哺乳類、土壌動物、鳥類など非常に多岐にわたる。これらの材料を用いてこれまでの日本の生態学では考えられなかったほどの大規模な野外実験や、精細な長期観察によって、動植物の相互作用、攪乱の効果、森林の垂直構造が昆虫の群集配列に及ぼす影響、生態系境界面での物質の移動に伴う生物の資源利用などが明らかされた。 これらの研究成果は日本の生態学に寄与するもっとも重要なもののひとつとなるであろう。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 1996年 -1997年 
    代表者 : 甲山 隆司, 工藤 岳, 植村 滋, 大原 雅, 佐藤 利幸, 露崎 史朗
     
    北海道の低標高域に残存する北方混交林は、その緯度帯の森林植生としては植物種多様性が高い系である。本研究では、北海道の北方混交林を対象に、多年生草本の種多様性が維持されるメカニズムを解き明かすことを目的とした。 前年度に引き続き、札幌市東郊の野幌森林公園内と、北海道大学苫小牧演習林内およびその近郊を中心に調査を継続した。苫小牧では2年間の林床草本群集のフェノロジーについてデータを蓄積し、融雪と林冠の展葉開始の年変動にともなって、積算受光量を一定に調節するような季節性の変化が存在することを見いだした。さらに季節に沿った各部分重の間の相対生長関係を6種について追跡調査し、種差が少なく葉に多くを分配するパターンを記録した。繁殖に注目した調査としては、一回繁殖型植物のオオウバユリ個体群の空間パターンを継時的に解析した。また、あらたに円盤接触法を考案して、葉群の垂直構造の定量的解析を行なった。選択的な採食圧にともなう群集の変化の解析を、夏季の馬の林間放牧系で調査した。さらに、対象地域の広域分布特性を空間スケール依存性として把握するために、シダ植物群について分析を行なった。 以上の基礎調査で明かにした群集パターンに基づいて、共存する種間の形態、繁殖持性、季節戦略、そして微環境のあいだのシンドロームについて、考察を行なった。
  • 文部科学省：科学研究費補助金(奨励研究(A))
    研究期間 : 1996年 -1996年 
    代表者 : 露崎 史朗
     
    火山における微環境の変化と実生の定着様式との対応関係を明らかにするために、主として北海道有珠山において永久調査区法・バイオマス測定・個体追跡・環境要因測定等の調査実験を行い、結果を以下のように得た。微環境は、植生発達を伴い大きく変化し、それに対応して実生の定着率が規定されている。火山において実生死亡率は非常に高く、個体にとって発芽に要する期間常に安定したセイフサイトを獲得することが生存および繁殖にとって重要なものである。一方、定着に成功すれば、実生生長には栄養分が必要不可欠である。しかしながら、有珠山では土壌栄養は、灼熱損料でわずかに数パーセントと非常に低かった。したがって、種子の定着には、地表の凹凸などの微環境とこれに関与する要因である斜面斜度、土壌粒径分布、土壌移動強度などの物理的要因が重要なものであることが示唆された。一方、定着に成功した実生は、生長に必要な光及び栄養分獲得、そして土壌移動に耐えるためにも地下器官を大きく発達させることが予測された。実生の生長には土壌要因、光要因ともに重要であるが、土壌栄養は貧栄養状態でほぼ均一に分布しているため、光環境によって実生の成長量更には死亡率が規定されていた。実生追跡調査によって得られたデータ(各プロットのアロ-ケーションデータ、実生個体数、死亡率)、さらに、有珠山における12年間以上の追跡調査データをもとに、各植物の動態および環境変動を定量化し、オ-ディネーション分析を行い個々の環境要因の植生発達への寄与率を定量化した。その結果、植生回復初期には土壌移動が主たる植生発達規定要因となるが、時間の経過につれ、その外の要因が個々のサイトによって重要なものとなっていくことが示唆された。
  • 日本学術振興会：科学研究費助成事業 国際学術研究
    研究期間 : 1995年 -1996年 
    代表者 : 福田 正己, FEDOROV A.N., SIDORENKO V., VINOKUROVA A, ZIMOV A.S., GRIGORIEV M., KUNISTKY V.V, RUSAKOV V.G., IVANOV B.B., 石崎 武志, 露崎 史朗, 安永 智秀, 高橋 邦秀, 佐藤 利幸, 渡部 英昭, 戸田 正憲, RUSAKOV V.C.
     
    1 東シベリア永久凍土の気候温暖化への応答-目的と方法- シベリア永久凍土は、最近の気候変動、特に温暖化の傾向に対して、大規模融解が拡大している。永久凍土は単に受動的に応答するのみならず、永久凍土中に貯留されたメタンガスを融解により大気に放出する。その結果、大気中のメタンガス濃度を増加させ、更なる温暖化を引き起こす。こうした温暖化への能動的な応答が、将来の温暖化にどのように影響するか、その予測と評価を行うために現地調査を行った。現地調査では、凍土そのものの応答・特に過去に生産・貯留されたメタンガスの成因と放出機構、凍土中の地下氷「エドマ層」の分布など、凍土圏そのものの調査・研究と、凍土を覆う植生や動物生態からみた応答と総合的な研究を実施した。 2 シベリア永久凍土中の地下氷「エドマ層」の成因と形成時期 東シベリアは過去7万年前の最終氷期以降、厚い氷床に覆われることはなかった。そのため、東シベリアには1000mを超える厚さの永久凍土が形成されていた。その形成過程で、レナ河・ヤナ河・インジギルガ河・コリマ河といった、永久凍土地域を南北に貫く大河の下流と、北極海沿岸地域では、エドマと呼ばれる地下氷の集積があった。この地下氷には、部分的に高濃度のメタンガスが含まれ、それが大気へ放出されることで、将来の温暖化に寄与する。そこで、エドマ層の成因とその分布を掌握することは、シベリア永久凍土の能動的応答を理解する上で欠かせない。本研究計画では、エドマ層の分布や形成時期が、東シベリアの他の地域と異なるコリマ河の下流地域と河口付近を主な調査地域として選んだ。コリマ河支流のスタドヒンスカヤ河沿いに比高20mの段丘が発達している。Pluhinoでは13mの厚さのエドマ層が露出している。さらに支流のアニュイ河でも類似の段丘が発達している。エドマ層に含まれる有機物を用いて、^<14>C年代測定を行った。その結果、エドマ層の下部は約4万年前から堆積が始まり、中位で2.5万年前であった。最上位の年代は決定されなかったが、エドマ層を覆う泥炭から、少なくとも後氷期(1.3万年前)には、エドマ層の堆積は終了したと判断される。コリマ河の本流沿いの高位段丘が発達するが、そこの年代は最上位で33,000年前であり、明らかに他の地域より古い。氷に含まれるメタンガス濃度と酸素同位体は、下層では変動が大きく、2.5万年前からは、より寒冷側にシフトし、かつ安定化している。これは、エドマ層が最終氷期の亜間氷期(カルギンスキー期4万-2.3万年前)が、気候不安定期であり、グリーンランド氷床コアー解析から明らかになった、ダンスガード-オスガ-不安定期に対応することがわかった。形成機構では、いわゆる同時発生的な氷楔に起因している。 3 コリマ河の氾濫原(湿原)から発生するメタンガスとそれを制御する環境要素 現在の環境化では、夏季に水分飽和となる湿原は、メタンガス発生源としての役割が大きい。そこで、コリマ河下流の湿原で、6月から9月までの長期観測を行い、メタンガスフラックスの変動とそれに影響する環境要素を調査した。その結果、永久凍土中の夏季融解層とそこの平均地温との積を指数とする実験式を得た。それを適用して、シベリアのツンドラ全域から発生するメタンガス量を10^<12>g(テラグラム)であると推定した。 4 気候変動が植生の分布と多様性に与える影響 気候の温暖化、特に夏季温度の上昇は、植生の分布と種構成に大きく影響する。コリマ河河口でのツンドラ-タイガ移行帯では、草本の種構成は北海道の釧路湿原に匹敵することがわかった。これは、2万年前の最終氷期以降の温度上昇が大きく、植生がかなりの速度で北上したことを裏付ける。さらに、永久凍土中の堆積物から採取した花粉により、植生回復の速度の速さが示された。 5 シベリアタイガの森林火災が気候変動に与える影響 森林機能を調査したグループは、森林に貯留されている炭素が一気に大気へ放出される森林火災についての評価を試みた。森林火災はCO2の直接的放出のみならず、本来森林が備えていた炭素呼吸(CO2を吸収し、O2を放出する)機能を損なう。そのため、2重の意味で大気へのCO2の放出源となる。火災のタイプ分けを行うには、樹木の根の部分の呼吸量が重要であることが、現地での観測から判明した。 6 土壌動物及び小動物の生態的特徴 タイガ及びツンドラに生息するショウジョウバエの生態的分布は、森林の更新過程や土壌生成に関わる指標となる。動物生態班は、森林の垂直分布によるショウジョウバエの棲み分けを調査した。その結果、新たに3種の新種を発見し、森林成立に依存する小動物の種の多様性が成り立つという知見を得た。
  • 文部科学省：科学研究費補助金(奨励研究(A))
    研究期間 : 1994年 -1994年 
    代表者 : 露崎 史朗
     
    火山における植物群集発達機構を明らかにするために主として有珠山において調査研究を行った。合わせて米国セントヘレンズ山噴火後の植生発達様式との比較研究を行った。本年度の主な成果は以下の通り。1.火山灰堆積地において微環境と実生の定着様式には強い対応関係が認められた。特に、地表面が軽石で覆われた所及びガリ-やリルの内部に実生は多かった。従って、実生出現には物理的なsafe siteの供給が必要不可欠なものと考えられた。2.実生の多かった所の土壌栄養分(灼熱損量・NPK等)は実生の少なかった所と比べて必ずしも高い値は示さず、土壌栄養的なものよりもむしろ物理的要因が実生の定着には重要なものと考えられた。3.旧表土中に生存する埋土種子集団を効率良く土壌中から抽出する方法を考案した。また、本手法は旧表土ばかりでなく、草地土壌等においても適用可能であることを示した。4.Canonical correspondence analysisによる植生解析にあたり、植物個体数及び被度を用い比較した所、異なる環境要因が両者を規定していることが明らかとなった。このことは各植物種の栄養繁殖と種子繁殖の違いに起因しているものと考えられた。更に、種子侵入には周辺植物供給起源の質及び量が、植物発達には地表面の安定性が重要なものと考えられた。5.有珠山とセントヘレンズ山では噴火に伴う撹乱強度の類似した生息地では群集構造的に類似した植生が発達しており、撹乱は初期植生構造を大きく規定しているものと考えられた。
  • 日本学術振興会：科学研究費助成事業 奨励研究(A)
    研究期間 : 1992年 -1992年 
    代表者 : 露崎 史朗
  • 文部科学省：科学研究費補助金(重点領域研究)
    研究期間 : 1992年 -1992年 
    代表者 : 露崎 史朗
     
    これまでの調査研究によって、4つの植物供給起源を明示し、これらの植物の生活型・供給起源と回復様式との対応様式を確定し、さらに、有珠山火口原域における種子の定着域を微地形レベルで明らかにした。本科研においては永久調査区内において種子の定着位置及び発芽位置を調査し実生にとってのセイフサイトが種子にとってのセイフサイトになりうることを示し、また、散布された種子と微地形との対応関係を明らかにした。特に、種子発芽にとって不利である粒径の大きな土壌上において種子がトラップされやすいため、結果的に微地形変化の大きな所で植生回復が早く進むことを示した。さらに、散布種子を土壌中から回収し同定選別を行い、これらの種子を実験室において光条件を変えて発芽試験にかけて最適発芽温度及び光条件を決定した(温度可変インキュベータを本科研にて購入)。次に、発達した大型多年生草本の光合成能力を野外において階層別に測定し、さらに最下層植物の光合成能を裸地に定着しているものと比較し、これらの植物が下層形可能な要因を探る(調査実験継続中)。これらの結果と今までの結果を合わせることによって、植物群集の垂直方向への発達様式とその要因を考察した。有珠山においては、現在でもなお個体数は激しく変動しており安定した変動傾向を得るためにも今後とも継続調査を行うことが重要であるが少なくともこれまでに上記のような結果を本科研によって得ることができた。
  • 日本学術振興会：科学研究費助成事業 奨励研究(特別研究員)
    研究期間 : 1990年 -1990年 
    代表者 : 露崎 史朗
  • 撹乱地(火山・スキー場・湿原等)における植物群集構造・動態の解明
    研究期間 : 1984年
  • Structure and dynamics of plant communities after disturbances
    研究期間 : 1984年

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