Comparison of fish community with different human disturbance: A case study of Taizi River catchment, China

Background/Question/Methods  In the developing countries, agriculture, urbanization and deforest are three important essentials for development, but the effect of these human disturbance on ecosystem, especially on the freshwater ecosystem is still with little attentions. Moreover, the unbalance of regional development resulted in the varied degradation degrees of river ecosystem health in these countries. So the urgent mission is to understand the status of freshwater ecosystem under different levels of human disturbance, and to find the key factors that confined the freshwater ecosystem health. This study was conducted on the six typical streams, including Taizi south stream (TS), Xiaotang stream (XT), Tang stream (TA), Lan stream (LA), Nansha stream (NS) and Beisha stream (BS) in Taizi River catchment, which is located in the northeastern of China to describe the structure of fish assemblages and the relationship to chemical parameters. TS & XT are upper streams with less human disturbance, whereas TA & LA and NS &BS are middle and lower streams with intermediate and severe human disturbance, respectively. This study was conduct on the summer of 2009 and 2010.

Results/Conclusions A total of 6418 specimens representing 32 species in nine families were captured from the six streams. The most common species were Phoxinus lagowskii with frequencies of occurrence of 55.13%. The results showed that the water quality decreased with the increase of human disturbance for six streams. Cluster results based on the fish assemblage showed that two lower streams with severe human disturbance were different from the other streams. Meanwhile, the fish diversity and trophic structure complexity were also lower quietly in NS & BS because of the poor water quality. Herbivore fish was not appeared in NS & BS due to the worse riparian vegetation conditions found in the survey. Canonical Correspondence Analysis found out that TDS, TN, SS and DO were the important water parameters influencing the fish spatial distribution. TDS and TN were the main parameters affecting the fish spatial distribution, and represented human disturbance, such as urbanization and agriculture. In conclusion, six streams showed the different fish assemblage structure with different human disturbance, so the fish protective measures should be drawn up according to different stream characteristics, and the nitrogen pollution should be pay close attention to the streams with severe human disturbance.