日本の有機農法水田における水生貧毛類の群集構造と季節変化 Community structure and seasonal changes in aquatic oligochaetes in an organic paddy field in Japan

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Author(s)

    • 谷地 俊二 Yachi Shunji
    • 横浜国立大学大学院環境情報研究院土壌生態学研究室 Soil Ecology Research Group, Graduate School of Environment and Information Science, Yokohama National University
    • 金子 信博 Kaneko Nobuhiro
    • 横浜国立大学大学院環境情報研究院土壌生態学研究室 Soil Ecology Research Group, Graduate School of Environment and Information Science, Yokohama National University

Abstract

神奈川県鎌倉市にある冬期湛水型の有機農法水田における水生ミミズ類の種組成,個体数密度,バイオマスを,冬季を除いた2010年6月から2011年5月まで調べた.水生ミミズ類の種構成は8種類からなり,他の水田や富栄養湖に優占するL.hoffmeiteriとB.sowerbyiが優占していた.鎌倉水田における水生ミミズ類の個体数密度は2,822m^<-2>であり,似た種構成を記録した北日本(50,000m^<-2>)やフィリピン(8,200m^<-2>)の水田と比べ低かった.また,渓流性のE.yamaguchiiが生息していた.

Field surveys of aquatic oligochaetes were conducted in an organic paddy field once per month in Kamakura, central Japan between June 2010 and May 2011, except during winter. We found eight aquatic oligochaete taxa. The species composition agreed with results from other paddy fields and eutrophic lakes in Japan. The oligochaete community was dominated by the tubicifine Limnodrilus hoffmeisteri and the rhyacodriline Branchiura sowerbyi. The tubicifine Embolocephalus yanaguchii was also collected. This species has been most frequently reported from springs and their outlet streams. Total population density and biomass were 2800 m^<-2> and 21.2 g wet wt. m^<-2>, respectively, lower than those in other similar paddy fields in northern Japan and the Philippines. The population dynamics of B. sowerbyi were examined by size distribution. Growth and reproduction continued until September; however, growth was reduced beginning in October. B. sowerbyi overwintered at various development stages, and newly born individuals were found beginning in April. The management practice for this paddy (organic, winter flooding) seemed to disturb aquatic oligochaeta less than does conventional farming (chemical, winter drainage), therefore the population remained stable throughout the year.

Journal

  • Edaphologia

    Edaphologia 90(0), 13-24, 2012

    The Japanese Society of Soil Zoology

References:  45

Codes

  • NII Article ID (NAID)
    110009426113
  • NII NACSIS-CAT ID (NCID)
    AN00334874
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    0389-1445
  • NDL Article ID
    023580937
  • NDL Call No.
    Z18-1362
  • Data Source
    CJP  NDL  NII-ELS  J-STAGE  JASI 
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