The diversity of predatory species plays a key role in ecosystem functioning but our understanding of the mechanisms underlying their coexistence is limited, particularly in freshwater ecosystems. Northern pike Esox lucius, European perch Perca fluviatilis and pikeperch Sander lucioperca are three widespread predatory species in European lakes, where they often coexist. As potential competitors, we hypothesised that partitioning habitat is a determinant of species coexistence. This was tested by quantifying the variability of their habitat use in tracking adult individuals in the Bariousses reservoir (France, 86.6 ha, mean depth 7.1 m). Specifically, we investigated their distribution along the littoral–pelagic and depth axes along the daily cycle and across seasons. From littoral to pelagic waters were first found pike, then perch and finally pikeperch. Pike was the closest to the surface while pikeperch was the deepest. This general pattern was, however, variable across seasons with the three species located in the upper layer in summer during reservoir stratification. Individuals were more evenly distributed along the littoral–pelagic axis and closer to the bottom when water was mixing (autumn, winter). In summer, perch used more intensively in the pelagic zone during the daytime. Other species did not show any diel change of habitats. Our results highlighted that species coexistence is associated with habitat partitioning among these three predators, with perch showing a more variable behaviour regarding habitat characteristics. Now more than ever, in the context of global change which modifies habitats, it is of crucial importance to understand the coexistence mechanisms of species that shape ecosystems.

中文翻译：

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温带水库中三种捕食性鱼类的栖息地划分

捕食性物种的多样性在生态系统功能中起着关键作用，但我们对其共存机制的理解有限，特别是在淡水生态系统中。北梭子鱼Esox lucius、欧洲鲈鱼Perca fluviatilis和梭鲈Sander lucioperca是欧洲湖泊中三种广泛分布的掠食性物种，它们经常共存。作为潜在的竞争对手，我们假设划分栖息地是物种共存的决定因素。这是通过量化它们在 Bariousses 水库（法国，86.6 公顷，平均深度 7.1 米）中追踪成年个体的栖息地使用的可变性来测试的。具体来说，我们调查了它们在沿岸 - 远洋和深度轴沿每日周期和跨季节的分布。从沿海到远洋水域首先发现梭子鱼，然后是鲈鱼，最后是梭鱼。派克是最接近地表的，而派克鲈鱼是最深的。然而，这种一般模式在不同季节是可变的，在夏季水库分层期间三种物种位于上层。当水混合时（秋季，冬季），个体沿着沿海 - 远洋轴分布更均匀，更靠近底部。夏季，鲈鱼白天在远洋带的使用更为频繁。其他物种没有表现出任何栖息地的变化。我们的研究结果强调，物种共存与这三种捕食者之间的栖息地划分有关，鲈鱼在栖息地特征方面表现出更加多变的行为。现在比以往任何时候都更重要的是，在改变栖息地的全球变化的背景下，了解塑造生态系统的物种的共存机制至关重要。其他物种没有表现出任何栖息地的变化。我们的研究结果强调，物种共存与这三种捕食者之间的栖息地划分有关，鲈鱼在栖息地特征方面表现出更加多变的行为。现在比以往任何时候都更重要的是，在改变栖息地的全球变化的背景下，了解塑造生态系统的物种的共存机制至关重要。其他物种没有表现出任何栖息地的变化。我们的研究结果强调，物种共存与这三种捕食者之间的栖息地划分有关，鲈鱼在栖息地特征方面表现出更加多变的行为。现在比以往任何时候都更重要的是，在改变栖息地的全球变化的背景下，了解塑造生态系统的物种的共存机制至关重要。