MACRO-PATTERNS OF SPECIES DIVERSITY AND STANDING CROPS OF MACROZOOBENTHOS IN THE YANGTZE RIVER BASIN

We summarize macro-patterns of macrozoobenthos in the Yangtze River basin in this paper. A total of 1033 taxa (species/genus) belonging to 3 phyla, 7 classes, 162 families and 513 genera have been recorded from the Yangtze River Basin, including 121 annelids, 318 molluscs and 594 arthropods. In terms of taxa distributions, the species/genus number of annelids and of molluscs in the middle reaches were the highest, while that of arthropods in the upper reaches was the highest; the species/genus number of annelids and of molluscs in the lakes were the highest, while that of arthropods in the tributaries was the highest; the species/genus number of macrozoobenthos in the middle mainstem sub-basin ranked first, and that of the upper mainstem sub-basin, of the Jinshajinag sub-basin, of the Lake Dongting sub-basin and of the Lake Poyang sub-basin second. The total density of macrozoobenthos in the Yangtze River basin was 672 ind./m², and insects were predominant; the total biomass was 34.22 g/m², and molluscs were predominant. In terms of standing crops distribution, the total density of macrozoobenthos in the middle reaches was the highest, the total biomass in the lower reaches the highest, while the total standing crop in the upper reaches was the lowest; the total density and biomass of macrozoobenthos in the lakes ranked first, those in the tributaries second, and those in the mainstem last; the total density of macrozoobenthos in the Lake Taihu sub-basin was the highest, and the total biomass in the Lake Poyang sub-basin was the highest. Our study indicates that the upper and middle mainstem sub-basins, the Jinshajiang sub-basin, the Lake Dongting sub-basin and the Lake Poyang sub-basin are important distribution regions for macrozoobenthos. By integrating more information of aquatic organisms, we should make comprehensive and systematic conservation planing of the Yangtze River system and implement them as soon as possible.