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尾瀬沼深底部の底生動物群集 : 1986年と2018年の比較
大高, 明史;木村, 直哉
Permalink : http://hdl.handle.net/2115/84948
JaLCDOI : 10.14943/lowtemsci.80.439
KEYWORDS : 尾瀬沼;深底部;底生動物;長期変化;Lake Ozenuma;profundal zone;zoobenthos;long-term change
Abstract
2018年に尾瀬沼深底部で底生動物の構成と現存量を調べた．大型底生動物群集は，貧毛綱3種，ユスリカ科2種，フサカ科1種の計6種からなり，貧毛綱ミズミミズ科のユリミミズが優占した．同じ地点で1986年に行った調査ではイトミミズが優占していたことから，この間にイトミミズからユリミミズへの優占種の交代が起こったことが示唆される．これには，近年の湖底温度の上昇が関係している可能性がある．
Composition and abundance of macrozoobenthos were studied in the profundal bottoms of Lake Ozenuma in 2018. Six species of macrozoobenthos consisting of three oligochaetes, two chironomids and one chaoborid were recorded from the study sites, of which a tubificine oligochaete, Limnodrilus hoffmeisteri dominated. Compared with past benthological records in Lake Ozenuma in 1986, Limnodrilus hoffmeisteri increased, while those of another tubificine Tubifex tubifex decreased in the present study. The change in the oligochaete structure could be caused by increase of bottom temperature in recent years.
Composition and abundance of macrozoobenthos were studied in the profundal bottoms of Lake Ozenuma in 2018. Six species of macrozoobenthos consisting of three oligochaetes, two chironomids and one chaoborid were recorded from the study sites, of which a tubificine oligochaete, Limnodrilus hoffmeisteri dominated. Compared with past benthological records in Lake Ozenuma in 1986, Limnodrilus hoffmeisteri increased, while those of another tubificine Tubifex tubifex decreased in the present study. The change in the oligochaete structure could be caused by increase of bottom temperature in recent years.
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