Springs are unique and vulnerable habitats, which have always been rather out of focus of the scientist interest. Nevertheless, they frequently host very diverse and species-rich assemblages with high proportion of species more or less adapted to their unique environment and can act as biodiversity hotspots in some areas. The Western Carpathian springs are helocrene springs and represent wide variety of different habitat types, from mineral rich sparsely-vegetated or bryophytes-rich covered helocrenes to acidic peaty sites. Such diversification allows the creation of highly diverse assemblages, in which Chironomidae usually dominate in both species richness and abundance. The aim of this study was to provide a comprehensive overview of chironomid assemblages inhabiting the unique environment of spring fens and factors driving the metacommunity structuring and populations of individual taxa. We examined chironomid assemblages of 62 small, treeless helocrenes sites, which are highly isolated from each other by the terrestrial environment constituting dispersal barriers such as the east-west oriented mountain ridges and valleys. The sampling was performed to cover mesohabitat heterogeneity of study sites. Two main mesohabitats were sampled, the plot with flowing water and coarser substratum near water source (the lotic mesohabitat), and water-logged soil with standing water (the lentic mesohabitat). Study sites hosted nearly 100 chironomid taxa, both mesohabitats were inhabited by chironomid assemblages similar in number of species and abundances and the local environment was proved to be the main driver of compositional changes in chironomid assemblages as expected. Moreover, the significant spatial structure of assemblages was found at the lentic mesohabitat, while biotic interactions described by the abundance of Gammarus fossarum and taxa richness and abundances of predators did not significantly contribute to compositional changes in assemblages at any mesohabitat. Nevertheless, taxa-specific responses revealed populations of many taxa significantly affected by biotic interactions, especially at the more stable lotic mesohabitat, which is in concordance with suggested greater importance of biotic interactions at stable environment. Our results emphasized the importance of multilevel approach in community ecology for proper distinction between different mechanisms of metacommunity structuring. Biotic interaction such as competition can result into the same community patterns as environmental filtering, thus the involvement of detailed analyses of species requirements and interactions is necessary.

中文翻译：

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西喀尔巴阡海陆龟的摇蚊科：元群落结构及其在独特栖息地的驱动因素

泉水是独特而脆弱的栖息地，这一直是科学家关注的焦点。然而，它们经常拥有非常多样化和物种丰富的组合，其中高比例的物种或多或少地适应了其独特的环境，并且可以成为某些地区的生物多样性热点。西喀尔巴阡山泉是海藻泉，代表了各种不同的栖息地类型，从富含矿物质的稀疏植被或富含苔藓植物的海藻到酸性泥炭地。这种多样化允许创建高度多样化的组合，其中摇蚊科通常在物种丰富度和丰度方面占主导地位。本研究的目的是全面概述栖息在春季沼泽独特环境中的摇蚊组合，以及驱动个体分类群的元群落结构和种群的因素。我们检查了 62 个小型、无树木的 helocrenes 站点的摇蚊组合，这些站点通过构成分散障碍的陆地环境（例如东西向的山脊和山谷）彼此高度隔离。进行抽样以涵盖研究地点的中生境异质性。采样了两个主要的中生境，水源附近有流水和较粗糙基质的地块（积水中生境）和积水的积水土壤（静水中生境）。研究地点托管了近 100 个摇蚊类群，两个中生境都居住着种类数量和丰度相似的摇蚊组合，并且当地环境被证明是摇蚊组合组成变化的主要驱动力，正如预期的那样。此外，在缓慢的中生境中发现了组合的显着空间结构，而由 Gammarus fossarum 的丰度和分类群的丰富性和捕食者的丰度所描述的生物相互作用对任何中生境中组合的组成变化没有显着贡献。尽管如此，特定分类群的反应揭示了许多分类群的种群受到生物相互作用的显着影响，特别是在更稳定的中间生境中，这与在稳定环境中生物相互作用的更大重要性一致。我们的结果强调了社区生态学中多层次方法的重要性，以适当区分元社区结构的不同机制。竞争等生物相互作用可以导致与环境过滤相同的群落模式，因此需要对物种需求和相互作用进行详细分析。