ABSTRACT

Understand how environmental factors correlate with the trophic structure of fish communities is a fundamental step to allow designing models for the functioning of stream ecosystems and planning conservation actions. Thus, this study aims to characterize the trophic structure of fish communities of streams of the Contas River basin and evaluate the relationships between local environmental factors (stream structure and limnological variables) and trophic structure. We sample nine streams of the Upper Contas sub-basin and nine of the Gongogi sub-basin using electric fishing. We analyzed the diet of 24 species, arranged in six trophic guilds, according to stomach contents: detritivores, omnivores, insectivores, invertivores, piscivores, and algivores. The results show high proportions of detritivores (46.62%), omnivores (28.55%), and insectivores (11.8%). Invertivores were correlated to colder streams, and with little proportion of sand in the substrate. Algivores were positively related to temperature and proportion of sand in the substrate. The relationship between other guilds and the environmental factors was not significant, probably due to limitations in the number of streams in the analysis. The sub-basins did not differ regarding the trophic structure, corroborating the perception that the trophic structure is more influenced by local factors than by broader scale factors.

摘要

了解环境因素如何与鱼类群落的营养结构相关是允许设计河流生态系统功能模型和规划保护行动的基本步骤。因此，本研究旨在描述孔塔斯河流域鱼类群落的营养结构，并评估当地环境因素（河流结构和湖泊学变量）与营养结构之间的关系。我们使用电钓对上康塔斯子流域的九个溪流和贡戈吉子流域的九个溪流进行采样。我们根据胃内容物分析了 24 个物种的饮食，这些物种分布在 6 个营养类群中：碎屑动物、杂食动物、食虫动物、反食动物、鱼食动物和藻类动物。结果显示，碎食动物（46.62%）、杂食动物（28.55%）、和食虫动物（11.8%）。反食动物与较冷的溪流相关，并且基质中沙子的比例很小。Algivores 与温度和基质中沙子的比例呈正相关。其他公会与环境因素之间的关系并不显着，可能是由于分析中流数的限制。子流域在营养结构方面没有差异，证实了营养结构更多地受当地因素影响而不是更广泛的尺度因素的看法。可能是由于分析中流数的限制。子流域在营养结构方面没有差异，证实了营养结构更多地受当地因素影响而不是更广泛的尺度因素的看法。可能是由于分析中流数的限制。子流域在营养结构方面没有差异，证实了营养结构更多地受当地因素影响而不是更广泛的尺度因素的看法。