月湖底栖动物的空间格局及其对水草可恢复区的指示

底质适宜是富营养湖泊恢复沉水植物(水草)的重要前提。大型底栖动物可综合指示底质的污染程度，于2002~2003年在武汉月湖开展了底栖动物水平分布对水草可恢复区指示作用的研究。首先通过月湖底栖动物与环境的相关分析，选择颤蚓科寡毛类作为底质营养状况的指示类群，然后利用同类湖泊群颤蚓与水草数据分析阈值，初步确定颤蚓密度≤100 ind/m2的底质适合水草生长，最后绘制月湖颤蚓分布的水平等值线，显示水草恢复的合适区域。在此基础上构建了应用底栖动物空间格局指示水草恢复区的技术原理框架。

INDICATION OF MACROPHYTE-RESTORABLE AREA BY SPATIAL PATTERN OF MACROBENTHOS IN YUEHU LAKE

Substrate suitability is critical to the restoration of submersed macrophytes in shallow eutrophic lakes.Since benthic animals are good indicators of sediment eutrophication,the authors conducted a pioneer study during 2002~2003 in Yuehu Lake,a hypertrophic urban lake of Wuhan City,with the purpose to explore the indicative value of macrobenthos distribution in determining macrophyte-restorable area.First,by correlating density and biomass of different benthos with trophic variables of sediment,density of Tubificidae(Oligochaeta) was selected as the best indicator.Secondly,on the basis of the data from 16 Yangtze lakes,a significant negative relationship between tubificids and macrophytes was detected,and it is demonstrated that the sediment with tubificids less than 100 ind/m~2 could be suitable for macrophyte growth.Finally, the horizontal isograms of tubificid density in Yuehu Lake were drawn,showing two proper places for macrophyte restoration.As the first attempt,the authors have established a principal framework for indicating macrophyte-restorable area by macrobenthos distribution,and will focus on the threshold analysis in the future.