The Ecological Research On The Zoobenthos In Ganjiang River Basin

Zoobenthos is the important part of the aquatic ecosystem, and plays an irreplaceable role in the material circulation and energy flowing. To a large degree, it reflects the healthy status of the entire aquatic ecosystem. In a seriously polluted aquatic ecosystem, the structure of zoobenthos is often simple, and part of the functionality is bereaved. The richness of a Zoobenthos community can reflect the degree of affection and the status of healthy of an aquatic ecosystem. Therefore, through researching the Zoobenthos ecology, we can understand the degree of water pollution and the major factor that affect the health of the water ecosystem in Ganjiang River basin. It not only helps us to develop a health evaluation technology system and criteria for the water ecosystem in Ganjiang River basin, thus finally assess the health status, but also provide scientific reference for reasonable development of the Ganjiang River basin and technical support for protecting the biodiversity, the health water ecological environment and the biological habitat in that area.This paper relies on the national 11th-Five-Year major scientific and technological program, Water Ecological Function Division, Target Quality Management and Technology Demonstration of Ganjiang River Basin (2008ZX07526-008-01). It's the first time of systematical ecology exploration of the zoobenthos of Ganjiang River basin. It mainly discusses the structure of zoobenthos community, functional feeding groups and the influence of environmental factors on the zoobenthos. It provides good reference for future pollution prevention & treatment of the Ganjiang River Basin and ecosystem evaluation for rivers.The main content and results are as follows:(1) In the zoobenthos investigation,4 classes of animals were found in total, which are annelids, molluscs, arthropods and nemathelminthes, including 27 families 73 species. They belong to hirudinea, oligochaete, polychaetes, malacostraca, insecta, gastropoda, lamellibranchia and nematoda, respectively. The mollusc was the dominant in three water status periods, that 18 families and 44 species in high-water period,20 families 44 species in low-water period and 20 families and 48 species in normal-water period. And bellamya aeruginosa was the favorable phylum in high-water period, Limnoperna Forfunei in low-water period, and Corbicula fluminen in normal-water period. Sensitive indicator species include Caridina denticulate sinensis, Gammarus sp. acrobrachium sp. Semisulcospiro libertinea Ephemeropsis sp. Gomphus sp. Limnoperna forfunei and so on, total 9 kinds, which indicates that water of Ganjiang River has been polluted to some degree.(2) The exploration results of zoobenthos functional feeding groups in Ganjiang River Basin shows that the scrapers and filter-collectors have the absolute advantage, and it's followed by collectors, predators, and shredders. The dynamic space analysis of Zoobenthos functional feeding groups implies that each functional feeding group can reflects the ecological characteristics of each resource niche on the spatial sequence, and their distribution formats were significantly limited by the spatial resources.(3) Base on the environmental factors on Zoobenthos, using canonical correspondence analysis (CCA) in the analysis of environmental factors affecting the benthic animal community of Gan jiang River Basin, the study found that, during wet period, the main environmental factors for community distribution are the water level, the latitude and longitude of river basin, flow velocity, heavy metals Pb, Zn and sulfide in the water, and that affecting the density distribution of benthic animals are the latitude and longitude of the basin, Cr6+, heavy metals Pb and Zn in the water, fecal coliform, sulfide and Cu in the water. For dry period, the main environmental factors affecting the distribution of benthic animal community are the latitude and longitude of the basin, water level, F-, Zn in the water and flow velocity, and that influence the density distribution of benthic animals are the watershed latitude, Zn and Cu in the water, phenol, and BOD5. We conclude that there is a strong correlation between the benthic fauna and environmental factors, and also for the benthic species composition, density and environmental factors.