Lake littoral zone,as a natural protection barrier of lake,is one kind of the most important ecotones between terrestrial and aquatic ecosystem.It plays an important role in diluting pollutant concentration,improving aquatic environment and providing aquatic animals′ habitat for their survival and reproduction.Therefore,ecological restoration of littoral zone is a necessary measure for lake protection and rehabilitation technologies.However,little work has been done on its ecosystem health assessment.Lake Taihu,being a typical large shallow lake,is one of the five famous greatest lakes in the east China plain.Its ecosystem has been deteriorating due to the more and more serious water pollution and eutrophication since 80′s.The environmental problems of Lake Taihu have attracted Chinese government′s careful attention.Many attempts for Lake Taihu′s pollution control have been made by the government.Some progresses have been achieved since the 10th Five-Year period.In the present work,a case study for assessing ecosystem health of lake littoral zones has been conducted in the littoral zone of Lake Taihu. A unique structure of littoral zone of Lake Taihu is its dike,which occupies about 73% of the total lake bank length.The dike blocks the natural material flow between the surrounding land area and the lake water,sequentially the material exchange between them was reduced to a great extent.Therefore,unlike the natural lakes without dike,the littoral zone of Lake Taihu does not cover the land area near the bank.After a careful analysis of the hydrology,geography,and aquatic plant distribution,we defined the littoral zone as the region ranging from dike edges to 50—100m water forward.Among the three common methods for ecosystem health assessment,namely,biological indicator,pressure-state-response(PSR) method and ecological health comprehensive index(EHCI) method,the last one was employed for the lake littoral zone,because it could better reflect the ecological health state from different aspects.According to the characteristic of littoral zone ecosystem,an ecosystem health assessment approach for lake littoral zone was developed based on the method of comprehensive ecological health index.The evaluating system in this approach is composed of objective level,normal level and index level.The normal level consists of 5 factors including water quality,sediment quality,emergent macrophyte conditions,and other biological physical conditions.In the index level,there are 15 factors including total nitrogen,total phosphorous,dissolved oxygen,emergent macrophyte cover and so on.Total 33 sites in the littoral zone of Lake Taihu were sampled.The normalization values of the observed sample data were used for ecosystem health assessment.The assessment results shows that among these 33 sampling sites,the percentages of 'very healthy','healthy','sub-healthy','ill' and 'serious ill' ecological situation are 0%,24.2%,21.2%,51.5% and 3.0%,respectively.This result indicates that more than half of the ecosystems in the 33 sampling sites were 'ill' state.Generally,the ecological health situation of the East Taihu Lake littoral zone was better than others,with an EHCI value just over the low limit score for 'healthy' situation.The ecosystems in the east lake side zone,Gonghu lake and the south lake side zone were in 'sub-healthy' state,while those in Meiliangwan,Zhushanwan and the west lake side zone were evaluated to be 'ill' state.It is shown that the ecosystem in Zhushanwan was in the worst ecological health situation among all of the littoral zones in Taihu Lake.The assessment results were coincident with the real situations.The assessment approach developed in this study is highly workable and reliable.This study may have some implications for the ecosystem health assessment of other lake littoral zones.