Spatial niche of major fishes in Qingshitan Reservoir

Abstract

[Objective] To elucidate and study interspecies relationship between the main fishes competing spatially in the Qingshitan Reservoir, clarify the correlation between the main fishes and environmental factors, and provide a reference basis for the water environment management and fishery resources protection and sustainable utilization in the Qingshitan Reservoir.

[Method] Based on data of fishery resources survey in the Qingshitan Reservoir in July 2020 (flood season) and January 2021 (dry season), the index of relative importance (IRI) was used to determine the importance of various fishes. Spatial niche breadth ( B _ij) and niche overlap ( Q _ij) of major fishes were examined using the mean crowding ( x*), Shannon, and Pianka indexes, and correlation between fish communities and environmental factors was explored by redundancy analysis (RDA) and detrended correspondence analysis (DCA).

[Result] In flood season and dry season of Qingshitan Reservoir, there were 16 and 13 major fish species, respectively. In flood season, dominant species were Rhodeus ocellatus, Hemiculter leucisculus, Coptodon zillii, Sinipercas cherzeri and Oreochromis niloticus; in dry season, the dominant species were Carassius auratus, Opsariichthys bidens, Rhodeus ocellatus, S. cherzeri and Cyprinus carpio. Niche breadth of major fish species in flood season and dry season were 0.11-1.58 and 0.04-1.64, respectively. C. zillii was the wide-niche species ( B _ij≥2.0) in flood season, and H. leucisculus in dry season. There were 5 medium-niche species (2.0> B _ij≥1.0) in flood season and 8 species in dry season, whereas there were 10 narrow-niche species (1.0> B _ij>0) in flood season and 4 species in dry season. The degree of Q _ij was different obviously in the two seasons. There were 41 pairs of species with significant Q _ij in flood season, accounting for 34.17% of the total number of pairs, with a relatively high overlap degree. Conversely, the major fish species overlap degree in dry season was low, with 19 pairs of species with significant overlap, accounting for only 24.36% of the total number of pairs. RDA showed that depth and total phosphorus (TP) were the factors directly affecting the distribution of the major fish species, which exhibited obvious niche differentiation.

[Conclusion] Obvious differences are found in spatial niche of different feeding fishes in Qingshitan Reservoir at different seasons and places. Whether in flood season or dry season, the B _ij of omnivorous fishes is large, that is, omnivorous fishes occupy a wider ecological niche than other predatory fishes do, and omnivorous fishes have a strong competition relationship with herbivorous fishes.

Abstract

摘要：【目的】阐明青狮潭水库主要鱼类在空间上竞争的种间关系, 明确主要鱼类与环境因子的关联性, 为青狮潭 水库的水环境治理及渔业资源的保护和可持续利用提供参考依据。 【方法】根据2020年7月 (丰水期) 和2021年1月 (枯 水期) 青狮潭水库的渔业资源调查数据, 采用相对重要性指数 (IRI) 确定各种鱼类的重要程度, 通过平均拥挤度 ( x*) 、 Shannon指数及Pianka指数分析主要鱼类的生态位宽度 ( B _ij) 和生态位重叠 ( Q _ij), 并以冗余分析 (RDA) 和去趋势对应 分析 (DCA) 探究鱼类群落与环境因子的相关性。 【结果】青狮潭水库丰水期、枯水期的主要鱼类分别有16和13种, 其 中, 丰水期以高体鳑鲏、 、齐氏罗非鱼、斑鳜和尼罗罗非鱼为优势种, 枯水期以鲫、马口鱼、高体鳑鲏、斑鳜和鲤为优 势种。青狮潭水库丰水期、枯水期主要鱼类的 B _ij范围是0.11~1.58和0.04~1.64, 其中, 广生态位种 ( B _ij≥2.0) 丰水期为齐 氏罗非鱼、枯水期为, 丰水期中生态位种 (2.0> B _ij≥1.0) 有5种、枯水期有8种, 丰水期窄生态位种 (1.0> B _ij>0) 有10种、 枯水期有4种。丰水期和枯水期主要鱼类的 Q _ij差异明显, 其中, 丰水期 Q _ij显著的种对有41对, 占总种对数的34.17%, 重叠程度相对较高; 枯水期主要鱼类重叠程度较低, 种对间 Q _ij显著的只有19对, 占总种对数的24.36%。RDA分析结 果显示, 水深和总磷是影响青狮潭水库主要鱼类生态位分化的直接因素, 主要鱼类受这些环境因子的影响表现出较 明显的生态位分化现象。 【结论】不同季节和空间下青狮潭水库不同食性鱼类的生态位存在明显差异。无论丰水期还 是枯水期, 杂食性鱼类的 B _ij都较大, 即杂食性鱼类较其他食性鱼类占据更广的生态位, 且杂食性鱼类与植食性鱼类存 在较强的竞争关系。