本文通过东湖与后湖浮游甲壳动物群落的长期变化、东湖浮游甲壳动物的空间分布格局、营养水平对东湖浮游甲壳动物群落体长的影响及围隔实验这四方面的研究揭示了东湖滤食性鱼类的捕食(下行效应)与富营养化(上行效应)对东湖浮游甲壳动物群落的影响。在1989-1998年期间，东湖I、II站近邻剑水蚤和微型裸腹？的生物量大幅上升，这两个种类优势度的上升与水体富营养化关系密切。80年代至90年代哲水蚤与剑水蚤生物量之比的明显下降与哲水蚤较低的内禀增长力有关。从60年代至199 7-1 998年，鱼类捕食压力的上升导致后湖枝角类的优势种由隆线？-亚种演替为逃避能力较强的短尾秀体？，后湖剑水蚤密度的上升导致右突新镖水蚤、长江新镖水蚤和特异荡镖水蚤的优势明显下降。浮游甲壳动物群落结构在东湖I、II、I I I、IV站间具有显著差异。微型裸腹？与近邻剑水蚤的优势度随水体营养水平的上升而上升，而大型枝角类(盔型透明？与透明薄皮？)的优势度随水体中鱼类捕食压力的上升而下降，哲水蚤相对于剑水蚤的优势趋向于随鱼类捕食压力的上升而下降。郭郑湖区浮游甲壳动物的生物量与水体营养水平间正的相关性不明显，而微型裸腹？、短尾秀体？和近邻剑水蚤在郭郑湖区的分布与鱼类捕食压力关系密切。从80年代至90年代，东湖浮游甲壳动物群落的平均体长呈现明显的上升趋势。浮游甲壳动物群落体长的上升由优势种体长的上升所导致，其中微型裸腹滔与近邻剑水蚤体长的上升与水体营养水平的上升关系密切。通过围隔实验发现，滤食性鱼类的捕食导致逃避能力强的种类(如哲水蚤)及世代时间短的种类(主要是小型枝角类)的优势增强。在鱼类捕食压力较高的水体中哲水蚤的生物量较低，因为无节幼体较容易被鱼类所捕获。通过对“下行效应”与“上行效应”对浮游甲壳动物群落影响机理的鲁敏：“上行效应”与“下行效应”对东湖浮游游甲壳动物群落的影响机理的深入研究，表明滤食性鱼类的捕食与水体的营养水平均为决定东湖浮游甲壳动物群落结构的重要因子。
Impacts of predation by filter-feeding fishes (top-down effects) and eutrophication (bottom-up effects) on crustacean zooplankton community were revealed through studies on the long-term changes of crustacean community, spatial distribution pattern and an enclosure experiment. In Lake Donghu, biomass of Cyclops vicinus and Moina micrura increased remarkably with eutrophication of the lake water during 1989-1998. The obvious decrease in biomass ratio of calanoids to cyclopoids at Stations I and II during 1980s to 1990s were related to relatively lower intrinsic increase rates of calanoids. In Lake Houhu, dominance of Daphnia carinata spp. was replaced by Diaphanosoma brachyurum from1960s to 1997-1998. Meanwhile, increase in density of cyclopoid was reponsible for decreased dominance of Neodiaptomus schmackeri, N. Yangtsekiangensis and Neutroditapomus incongruens. Significant differences in the structure of crustacean community were found among Stations I, II, III and IV. Biomass of M. micrura and C. vicinus increased with increased trophic level of the lake water, while biomass of large-bodied cladocerans (D. galeata and Leptordora kindti) decreased with increased fish predation, and relative abundance of calanoids to cyclopoids tended to decrease with increased fish predation. In Guozheng Hu area, no obvious positive correlation was found between the biomass of crustaceans and the trophic level of lake water, while distribution patterns of micrura, D. brachyurum and C. vicinus populations were related to predation of fish. From 1980s to 1990s, average length of crustacean community increased obviously due to increased average length of dominant crustacean species, and the increases of the average lengths of the dominant species, M. micrura and C. vicinus, were related to increased trophic level of the lake water. The enclosure experiment showed that dominance of evasive species (such as calanoids) and species with short generation times (generally small-sized cladocerans) increased by predation of filter-feeding fishes. Biomass of calanoids was low when fish predation was intensive, probably because their nauplii were more vulnerble. Through comprehensive studies on the mechanisms of top-down and bottom-up effects on the crustacean zooplankton community, the present researches indicate that both predation by filter-feeding fishes and trophic level of the lake water are important driving forces in shaping the structure of crustacean zooplankton community in Lake Donghu.