Predation may significantly control number and density of coexisting species. The effects of predation on species diversity have traditionally been tested in experiments and theoretical models of simple trophic systems. In complex natural ecosystems, however, disentangling multiple sources of variation is difficult. In groundwater‐fed environments, a significant effect of predation can be expected due to the relatively stable environmental conditions; however, it has never been properly examined. We analysed species diversity and total abundance of macroinvertebrate assemblages in 48 Western Carpathian spring fens, separately for whole sites and mesohabitat/season, and partitioned the effects of predation intensity from those of environmental variables in robust models using a bootstrapping technique. We verified our results by accounting for taxa resistant to predation. The assumption that predation‐mediated coexistence of species is the main mechanism responsible for the relatively species‐rich assemblages in the Western Carpathian spring fens was not supported. However, predation may significantly influence abundance of non‐predatory species and, under some conditions, it may contribute to explaining patterns in species diversity. The effect of predation did not differ between the mesohabitats with different stability. However, we found higher environmental control in spring and a stronger effect of predators in autumn, which suggests that different mechanisms influence fen assemblages in different seasons. Our study provides a new robust approach how to test the effect of predation on natural macroinvertebrate assemblages. The importance of predation was lower than expected in equilibrium assemblages but it may vary in time.

中文翻译：

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捕食者丰度是否影响春季沼泽平衡大型无脊椎动物组合的物种多样性？

捕食可以显着控制共存物种的数量和密度。捕食对物种多样性的影响历来在简单营养系统的实验和理论模型中进行测试。然而，在复杂的自然生态系统中，很难解开多种变异来源。在地下水补给的环境中，由于环境条件相对稳定，可以预期捕食效果显着；然而，它从未得到适当的审查。我们分析了 48 个西喀尔巴阡春季沼泽地的物种多样性和大型无脊椎动物组合的总丰度，分别针对整个地点和中生境/季节，并使用自举技术将捕食强度的影响与稳健模型中的环境变量的影响分开。我们通过考虑抗捕食的分类群来验证我们的结果。不支持捕食介导的物种共存是导致西喀尔巴阡山脉中物种相对丰富的组合的主要机制的假设。然而，捕食可能会显着影响非捕食性物种的丰度，并且在某些条件下，它可能有助于解释物种多样性的模式。捕食效果在稳定性不同的中生境之间没有差异。然而，我们发现春季环境控制更高，秋季捕食者的影响更强，这表明不同的机制影响不同季节的蕨类组合。我们的研究提供了一种新的稳健方法，可以测试捕食对天然大型无脊椎动物组合的影响。