利根川水系小貝川上流域の谷津内水路の魚類の生息密度に影響を与える環境因子の期別変化 [in Japanese] Seasonal Changes of Environmental Factors Influencing on Fish Population Density in Ditches of Hill-bottom Valleys Located in the Upper Stream of the Kokai River, the Tone River Basin [in Japanese]
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小貝川上流域の環境の属性が異なる5つの谷津で非灌漑期 (1～2月), 灌漑期 (5～6月), 移行期 (8～9月) に生息魚類の分布調査を行った. ヌマムツ, タモロコ, シマドジョウ, ドジョウ, ホトケドジョウの分布は期別で異なった. 生息密度を目的変数とした数量化1類解析では, ホトケドジョウでは三期とも谷頭と谷尻から各調査区までの水路距離が環境因子として抽出され, シマドジョウでは灌漑期で谷尻から各調査区までの水路距離, 最大水深, 流速, 水路床に対する砂被覆率が, ヌマムツでは非灌漑期で谷尻, 谷頭から各調査区までの水路距離, 最大水深, 流速, 岸辺下部のえぐれ面積率, シルト被覆率, 砂被覆率が, タモロコでは非灌漑期でえぐれ面積率が, ドジョウ1歳以上魚では移行期で谷尻, 谷頭から各調査区までの水路距離, 流速, 垂下植物被覆率が抽出された。以上から5種の生息場を期別で示した.
Population density of five fish species was investigated at five valleys with different environmental characteristics. The investigation was carried out during non-irrigation period (January and February), irrigation period (May and June), and transitional period (August and September). As a result, it was found that distribution pattem of <I>Numamutsu, Tamoroko, Simadojyo, Dojyo, Hotokedojyo</I> were different By using analysis of quantification theory I, environmental factors for each fish were identified. The factors obtained were summarized as follows; 1) distance of ditch from <I>Tanigashira</I> (upper most of hill-bottom valley) to each station, and from <I>Tanijiri</I> (lower most of hill-bottom valley) to each station were extracted as environmental factor of <I>Hotokedojyo</I>; 2) From <I>Tanijiri</I> to each station, maximum depth, water velocity, rate of sand riverbed area in May and June for <I>Simadojyo</I>; 3) From <I>Tanijiri</I> and <I>Tanigashira</I> to each station, maximum depth, water velocity, rate of undercut bank area, rate of silt and sand riverbed area in January and February for <I>Numamutsu</I>; 4) rate of undercut bank area in January and February for <I>Tamoroko</I>; and 5) distance of ditch from <I>Tanijiri</I> and <I>Tanigashira</I> to each station, water velocity, rate of overhanging vegetation in August and September for <I>Dojyo</I> one year old or over.
- Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering
Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering 75(1), 19-29, 2007-02-25
The Japanese Society of Irrigation, Drainage and Rural Engineering