Abstract: Based on the relative aggregation degrees among hierarchies of different agroecosystems,the author pro- posed that locational quotient model could be used to measure the locational superiority of agroecosystem.The main purpose of this paper is to provide a scientific basis for choosing agricultural marketable basesand establishing a high-efficient and sustainable agroecosystem.

Key words: macrozoobenthos, community structure,  , biomass, functional feeding group, bioassessment of water quality, Fenshuijiang Reservoir.