1. The importance of flow‐related factors to benthic organisms, as well as the role of habitat conditions in shaping aquatic communities during low‐flow periods, have been recognised. Despite this, the preferences of macroinvertebrates to the ratio of lentic to lotic habitats at the reach scale have not been accurately quantified in most instances.
2. Aquatic invertebrates and habitat features in a range of temporary rivers in Sardinia were investigated. The investigation focused on the flow‐related characteristics that contribute to defining the lentic–lotic condition of the river reaches. The relation of habitat features to benthic taxa distributions was assessed using multidimensional scaling. The main aim of the paper was to quantify the responses of taxa to the different lentic and lotic habitat conditions by applying hierarchical logistic regressions. Finally, taxon optima were aligned along the lentic–lotic gradient and the responses of different taxonomic groups compared.
3. Unbroken waves and imperceptible flow were correlated with benthic taxa variability, suggesting local hydraulics and turbulence have a major role in regulating community composition. The overall lentic–lotic character of the river reaches was also clearly related to the benthic taxa distribution. More than 80% of taxa were significantly related to the lentic–lotic gradient, and an asymmetrical response curve was the predominant model.
4. Benthic groups showed taxon optima clustered in different ranges of the lentic–lotic gradient. Odonata, Coleoptera, Hemiptera, and Mollusca preferred clearly lentic conditions. Diptera mainly ranged on the lotic side of the gradient, while Trichoptera were relatively uniformly distributed across the gradient. Ephemeroptera taxa clustered in intermediate lentic–lotic conditions, with two species preferring extremely lentic habitats. In general, optima converged at intermediate and extremely lentic conditions, presumably due, respectively, to the coexistence of different lentic and lotic features and to the highly diverse environmental characteristics under extremely lentic situations.
5. These results support the conclusion that dissimilar ecological factors act on benthic taxa along the lentic–lotic range and species favouring different lentic–lotic conditions are subjected to pressures of different nature. This should not be ignored when defining species preferences and studying community structure or relationships between species in Mediterranean rivers, which cyclically vary their habitat composition. In addition, the uneven distribution of optima of different groups along the lentic–lotic gradient might affect macroinvertebrate metrics when assessing ecological status or establishing reference conditions under variable climatic conditions.

中文翻译：

---

生境的透镜和抽动特性决定了地中海河流底栖大型无脊椎动物的分布

1. 人们已经认识到与流量有关的因素对底栖生物的重要性，以及在低流量时期栖息地条件在塑造水生群落中的作用。尽管如此，在大多数情况下，仍无法准确地量化大型无脊椎动物对伸手可及的范围中的动植物栖息地比例的重视。
2. 调查了撒丁岛一系列临时河流中的水生无脊椎动物和栖息地特征。这项研究的重点是与水流有关的特征，这些特征有助于确定河段的文物-冰川状况。使用多维标度评估栖息地特征与底栖生物分类分布的关系。本文的主要目的是通过应用分级逻辑回归来量化分类群对不同的透镜和抽水生境条件的响应。最后，将分类最佳化沿着透镜—地层梯度对齐，并比较了不同分类组的响应。
3. 连续的波浪和不易察觉的水流与底栖生物群的变异性相关，表明局部水力和湍流在调节群落组成方面起着重要作用。河道的总体文物特征与底栖生物群的分布也明显相关。超过80％的分类单元与透镜-倾斜梯度显着相关，并且非对称响应曲线是主要模型。
4. 底栖动物群显示分类群最优化聚类在透镜-梯度梯度的不同范围内。Odonata，鞘翅目，半翅目和软体动物更喜欢明显的透镜状条件。双翅目主要分布在梯度的抽水侧，而毛鳞翅目在梯度上相对均匀地分布。鳞翅目类群聚集在中等的透镜—乳腺条件下，有两个物种偏爱极透镜状的栖息地。通常，最佳状态在中间和极端透镜状态下会聚，大概是由于不同的透镜和吸液特征并存以及在极端透镜状态下高度多样化的环境特征所致。
5. 这些结果支持这样的结论，即不同的生态因子作用于沿透镜—地带范围的底栖生物群，并且有利于不同透镜—地带条件的物种受到不同性质的压力。在定义物种偏好并研究地中海河流中物种的群落结构或物种之间的关系时，这一点不容忽视。此外，当评估生态状况或在可变气候条件下建立参考条件时，沿透镜—地势梯度的不同群体的最优分布不均匀，可能会影响大型无脊椎动物的指标。