佐渡島の棚田放棄地における植物群落の成立と土壌および水環境との関係 Establishment of plant communities in relation to soil and water environments in abandoned terraced paddy fields on Sado Island, Japan

この論文にアクセスする

この論文をさがす

著者

    • 辻井 令恵 TSUJII Norie
    • 新潟大学大学院自然科学研究科:(現)(株)きものブレイン Graduate School of Science and Technology, Niigata University
    • 中田 誠 NAKATA Makoto
    • 新潟大学大学院自然科学研究科 Graduate School of Science and Technology, Niigata University

抄録

  1. 本研究は新潟県佐渡島の棚田放棄地において,さまざまな植物群落が成立している原因を,土壌,地下水,地形などの環境要因との関連から明らかにすることを目的とした.<BR>  2. 18ヵ所に調査プロットを設定し,植生,土壌,地下水位の調査を行うとともに,土壌と水のサンプルを採取し,化学性の分析を行った.<BR>  3. 本調査地の植物群落は,優占種の生育形や樹高,草本植物の種組成により,中生高木林,湿生高木林,中生低木林,湿生低木林,ヨシ群落の5タイプに分けられた.<BR>  4. 調査したすべての土壌断面で,棚田として利用していたころの作土層と心土層を確認でき,作土層の上部には,腐植を多く含んだ黒色層が形成されていた.<BR>  5. 平均地下水位は中生高木林と中生低木林で低く,逆に湿生高木林と湿生低木林,ヨシ群落で高く,両者の違いが明瞭だった.<BR>  6. 多くの土壌断面中にグライ層が存在し,その現れる深さは平均地下水位と強い相関を示した.<BR>  7. ヨシ群落では土壌表層に堆積した泥炭の影響で,他の群落タイプよりもC,N含有率が高かった.また,ヨシ群落と中生および湿生低木林では,中生および湿生高木林よりも土壌中のCaが多く,pHが高かった.<BR>  8. 斜面下部に位置するヨシ群落と湿生低木林では,斜面浸出水が地下水のおもな供給源と考えられ,中生および湿生高木林よりも地下水位の経時変動が小さく,各成分の含有率とpHが高かった.<BR>  9. 林床植生のデータを用いたDCAによる第I軸上でのプロットの配列は,平均地下水位,土壌,地下水の多くの化学性との間で有意な相関を示し,地下水位の高さに起因した土壌の水分環境傾度に沿った空間的な植生構造の変化を反映していると考えられた.<BR>  10. 棚田放棄後の植生遷移においては,畦および棚田間の法面の存在と周囲の植生の影響が大きく,高木林では,その内部を被陰することで林床植生の組成や優占度に影響を及ぼしていた.<BR>  11. 棚田放棄後は斜面位置や傾斜といった地形条件の違いが地下水位の高さやその変動パターンを通じて異なる植物群落を成立させ,さらに土壌や地下水の化学性にも影響を及ぼしていると考えられた.

Factors affecting plant community types in relation to soil and groundwater environments were studied in abandoned terraced paddy fields in the southeastern part of Sado Island, Niigata Prefecture, Japan. Plant communities were classified into forest, shrub, and reed communities based on growth form and height of dominant species. The forest and shrub communities were further divided into mesic and wet forest communities, and mesic and wet shrub communities, respectively, based on the species composition of the herb layer. Both the ploughed layer and the subsoil that were formed when the site was used as a paddy field were distinguished in all investigated soil profiles. A humus-rich black layer was formed in the top portion of the ploughed layer. A gley layer was recognized in most investigated soil profiles. Both the carbon and nitrogen contents of the soil in the reed community were higher than those in the other community types owing to the peat layer that accumulated in the top portion of the ploughed layer. The Ca content and pH of the soil were higher in the reed and shrub communities than in the forest communities. The average groundwater table level was significantly lower in the mesic forest and mesic shrub communities than in the wet forest, wet shrub, and reed communities. The depth of the gley layer showed a strong correlation with the average height of the groundwater table level. The fluctuation range of the groundwater table level was small, and the cation contents and pH of the groundwater were higher in the reed and wet shrub communities, which were located on the lower portions of the slope, than in the mesic and wet forest communities. Detrended correspondence analysis (DCA) using understory vegetation data showed significant correlations between the first axis of the DCA and environmental factors, i.e., the average groundwater table level and chemical properties of both the soil and the groundwater. The surrounding vegetation and levees around the terraced paddy field may have played important roles in plant succession after the terraced paddy fields were abandoned. Topographical conditions, such as slope position and inclination, may have affected the establishment of the different types of plant community because they affected both the height and fluctuation pattern of the groundwater table after the terraced paddy fields were abandoned.

収録刊行物

  • 植生学会誌

    植生学会誌 23(1), 37-54, 2006

    植生学会

参考文献:  44件中 1-44件 を表示

被引用文献:  4件中 1-4件 を表示

各種コード

  • NII論文ID(NAID)
    110007522375
  • NII書誌ID(NCID)
    AA11347548
  • 本文言語コード
    JPN
  • 資料種別
    ART
  • ISSN
    13422448
  • NDL 記事登録ID
    8906418
  • NDL 雑誌分類
    ZR3(科学技術--生物学--植物) // ZU4(書誌・図書館・一般年鑑--専門書誌)
  • NDL 請求記号
    Z18-3499
  • データ提供元
    CJP書誌  CJP引用  NDL  NII-ELS  J-STAGE 
ページトップへ