为了解河西走廊内陆河水系的鱼类多样性和资源现状, 作者于2019年4月至2023年10月在该流域设置了25个采样断面, 进行了8次调查。共采集鱼类9,743尾, 隶属于4目8科20属29种, 其中甘肃省重点保护鱼类有祁连裸鲤(Gymnocypris chilienensis)和黄河裸裂尻鱼(Schizopygopsis pylzovi) 2种, 列入《中国生物多样性红色名录》易危和近危的物种有4种, 河西走廊内陆河特有鱼类4种。3条内陆河水系现有鱼类以小型鱼类为主, 祁连裸鲤、酒泉高原鳅(Triplophysa hsutschouensis)、鲫(Carassius auratus)为优势种, 不同水系不同时间段优势种有一定差异。河西走廊内陆河水系鱼类多样性总体较低, 其中Margalef丰富度指数在夏季最高, 为2.215; Simpson优势度指数在秋季最高, 为0.715; Shannon-Wiener多样性指数和Pielou均匀度指数都在春季最高, 分别为1.463和0.716。黑河的Margalef丰富度指数和Shannon-Wiener多样性指数最高, 分别为2.767 ± 1.455和1.549 ± 0.432; 疏勒河的Simpson优势度指数和Pielou均匀度指数最高, 分别为0.755 ± 0.060和0.807 ± 0.095。3条内陆河上游与中下游的鱼类种类组成有明显差异, 采用冗余分析发现, 总磷是影响鱼类群落结构差异的主要因子。与20世纪80年代的调查数据相比, 祁连裸鲤和叶尔羌高原鳅(Triplophysa yarkandensis)的分布区域缩小, 其他高原鳅属(Triplophysa)鱼类的分布范围尚未有较大变化。水资源短缺、外来物种入侵和水利工程建设是影响河西走廊内陆河水系鱼类多样性和分布的主要因素。

Aims:The Hexi Corridor serves as a critical ecological protection area in Northwest China. This study aims to investigate the fish diversity and resource status within the interior drainage systems of this region.

Methods:From April 2019 to October 2023, eight fishery resource surveys were conducted at 25 sampling sections across inland river basin of the Hexi Corridor. The relative importance index (IRI) was used to determine the dominant species of the population. Fish diversity was analyzed using the Margalef richness index, Shannon-Wiener diversity index, Simpson dominance index, and Pielou evenness index. The Bray-Curtis similarity coefficient was used to cluster and sort the distribution characteristics of fish. Non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA) was employed to examine the gradient relationships between fish community composition and environmental factor using Canoco 5.0 software.

Results:A total of 9,743 fish belonging to 4 orders, 8 families, 20 genera and 29 species were identified. Among them, 12 species are indigenous, including Gymnocypris chilienensis and Schizopygopsis pylzovi, which are under Gansu Provincial protection. Schizopygopsis pylzovi was identified as a new recorded species in the interior drainage of Hexi Corridor, and four species, including Triplophysa yarkandensis and Silurus soldatovi, were classified as vulnerable or near-threatened under the Red List of Biodiversity of China. The fish populations were predominantly composed of small-sized species, with Gymnocypris chilienensis, Triplophysa hsutschouensis and Carassius cuvieri as the dominant species. Notable differences in dominant species were observed across different river systems and temporal intervals. The fish diversity in the inland river system of Hexi Corridor was generally low across the inland rivers. The Margalef richness index was the highest in summer (2.215), while the Simpson dominance index peaked in autumn at the 0.715. Both Shannon-Wiener diversity index (1.463) and Pielou evenness index (0.716) reached their maxima in spring. Among the rivers, the Heihe River exhibited the highest species richness index of Margalef (2.767 ± 1.455) and Shannon-Wiener diversity index (1.549 ± 0.432), whereas the Shule River recorded the highest Simpson dominance index (0.755 ± 0.060) and Pielou evenness index (0.807 ± 0.095), respectively. The NMDS analysis revealed significant differences in fish species composition between the upper and middle-to-lower reaches of rivers. Redundancy analysis indicated that total phosphorus was the primary environmental factor influencing fish community structure.

Conclusion:Compared with survey data from the 1980s, the distribution areas of Gymnocypris chilienensis and Triplophysa yarkandensis have been reduced, while the distribution areas of other Triplophysa species have remained relatively stable. Key factors affecting fish diversity and distribution in the region include water resource scarcity, invasive species, and water conservancy projects.