Fish diversity and threat factors in the Yunnan section of the Nujiang River
Aims:The Nujiang River is an important international river in southwestern China and one of the six major drainages in Yunnan.This study aims to understand the fish diversity and threat factors in the Yunnan section of the Nujiang River.Methods:A systematic survey of 53 sampling sites in the Yunnan section of Nujiang River from 2019 to 2020 was conducted.The indices of Margalef species richness index,Shannon-Wiener diversity index,Pielou's evenness index,Simpson dominance index was used to evaluate the diversity of fishes.Jaccard similarity index was used to evaluate the similarity of fish community structures in different rivers or reaches.The index of relative importance(IRI)was calculated to determine the dominant species.Pheatmap are used to analyze the threat factors.Results:A total of 89 fish species belonging to 59 genera,26 families,and 9 orders were recorded in the Yunnan section of the Nujiang River.In this study,51 fish species belonging to 42 genera,20 families and 6 orders were collected.The IRI analysis found that the dominant species in the Yunnan section of the Nujiang River was Schistura poculi,and the index score was much higher than other fish species.The species diversity index showed that the Shannon-Wiener index,Margalef species richness index,Simpson dominance index,and Pielou's evenness index of the Yunnan section of Nujiang River is 2.10,5.91,0.71,and 0.53,respectively.The mainstream of Nujiang River and its two larger tributaries,the Luomingba River and the Mengboluo River,had higher fish diversity.Similarity analysis showed that the fish composition of each section or river in the Yunnan section of the Nujiang River was quite different.Threat factor analysis found that the most threatening factors to the fish diversity in Yunnan section of the Nujiang River were agricultural and household waste pollution,fishing,invasive alien species,and hydraulic engineering and hydropower engineering construction.Conclusions:Agricultural and household waste pollution,fishing,invasive alien species,and hydroelectric project construction are the most threatening factors to the fish diversity in Yunnan section of Nujiang River.This study provides basic survey data for the conservation and scientific management of fish diversity in the Yunnan section of Nujiang River.This information will be useful for the ecological protection and high-quality development of Nujiang River basin.
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万方数据
