三峡水库坝前段蓄水前后枝角类的周年变化

三峡水库蓄水前后,作者从2002年6月至2004年7月按月在坝前段(茅坪—归州)采集枝角类,研究蓄水前后枝角类的变化,结果显示蓄水前该江段水流急不适合枝角类栖息,仅在水流相对较缓的岸边采集到2种;蓄水后水环境较适宜枝角类生活,周年内共采集到20种,并存在着明显的季节变化和水平分布上的差异,文中对其原因进行了分析讨论。  

Variation of cladocerans from Maoping to Guizhou in the Three Gorges Reservoir before and after impoundment

The Three Gorges Reservoir was filled at 1 Jun.,2003.The water level of the reservoir rose up to 135m.The lotic river ecosystem evolved into relative lentic reservoir ceosystem before the dam.The community composition of aquatic life changed with the environmental variation.We sampled the cladocerans at 5 sites from Maoping to Guizhou every month during June,2003 to July,2004.There only 2 species were sampled before impoundment at the 5 sites in the reservoir.This result showed the lotic ecosystem(didn't) suit for inhabit for cladocerans.There 20 species were sampled after impoundment at the 5 sites in the reservoir during the first year.The reservoir ecosystem supplied habitat for the water flea.The cladoceran composition changed with season and distribution after impoundment in the reservoir.The species except Bosmina coregoni and B.fatalis varied with season and showed different in composition.The species enriched at the first month(June,2003)after impoundment and in the spring(April,2004).Six species(D.brachyurum,Daphnia cucullata,Bosmina coregoni,B.fatalis,Bosminopsis deitersi and Alona guttata) distributed in five sampling sites.The others species distributed in part sampling sites.