The species composition of a community is driven by the dispersal capacity of the species forming that community and their ecological niche. While the ecological niches of EPTs (Ephemeroptera, Plecoptera and Trichoptera) are well-studied due to their wide use as indicators for the ecological status of freshwater ecosystems, their dispersal capacity has not yet been accurately characterized. Dispersion of the merolimnic EPT species during the terrestrial aerial adult stage is of special importance because the distance dispersed by active flight or passive wind drift is usually much larger compared to dispersion during the aquatic larval stage by active crawling or by drifting downstream.

The aerial dispersal distance has been directly measured for only a small number of EPT species. For most other species, the dispersal capacity is assessed indirectly using species’ traits that are mainly based on expert judgement and dispersal indices derived from trait information. In this study, we compiled a database of European EPTs’ aerial dispersal distances reported in empirical studies and compared them to the dispersal capacity of the species as described by five different dispersal indices (original and modified versions of Li’s Dispersal Capacity Metric DCM and Sarremejane’s Species Flying Propensity SFP as well as relative wing length).

The database included empirical data on 180 species, comprising 9.3% of European EPT species. Most data came from trap experiments with traps located at different distances from the assumed emergence point. Since the distance classes differed between studies and had to be translated to a fixed set of four distance classes here, several species had to be assigned to more than one class. To account for this uncertainty, five ordered logistic regression models, each one with a dispersal index as predictor and the ordinal-scaled aerial dispersal distance as response, were bootstrapped 10,000 times. In each run, species belonging to several distance classes were randomly assigned to a single class out of all possible classes. Since wing length had no significant effect on aerial dispersal distance in any of the 10,000 bootstrap runs, we question the use of this anatomical trait as an indicator for the aerial dispersal capacity. In contrast, a modified version of the DCM index was consistently related to the aerial dispersal distances (96%). The original SFP index had a significant effect in 100% of the model runs, indicating that this index is very well-suited as an indicator for the aerial dispersal capacity of European EPT species.

This study facilitates the assessment of European EPT flying distances by providing a compilation of empirical data on the topic and by recommending an accurate indirect method when empirical data is not available.

一个社区的物种组成由形成该社区的物种的分散能力及其生态位驱动。虽然EPT的生态位（星翅目，鞘翅目和毛鳞翅目）由于被广泛用作淡水生态系统生态状况指标而得到了充分的研究，但它们的扩散能力尚未得到准确表征。在陆地空中成年阶段，中色EPT物种的扩散尤为重要，因为与主动爬行或向下游漂移的水生幼虫阶段相比，主动飞行或被动风漂移所散布的距离通常要大得多。

仅对少量EPT种类直接测量了空气扩散距离。对于大多数其他物种，使用物种特征间接评估扩散能力，这些特征主要基于专家判断和从特征信息中得出的扩散指数。在这项研究中，我们建立了一个欧洲EPT在经验研究中报告的空中扩散距离的数据库，并将它们与该物种的扩散能力进行了比较，这由五个不同的扩散指数（李氏“ Dispersal Capacity Metric DCM”和“ Sarremejane's Species”的原始版本和修改版本）进行了比较。飞行倾向性SFP以及相对机翼长度）。

该数据库包括关于180种物种的经验数据，占欧洲EPT物种的9.3％。大多数数据来自陷阱实验，其中陷阱位于与假定的出现点不同距离处。由于不同研究之间的距离等级不同，并且在这里必须转换为四个距离等级的固定集合，因此必须将多个物种分配给一个以上的等级。为了解决这种不确定性，对五个有序逻辑回归模型进行了10,000次自举，每个模型均以分散指数作为预测指标，并按比例缩放的空中扩散距离作为响应。在每次运行中，将属于几个距离类别的物种随机分配给所有可能类别中的单个类别。由于机翼长度在10,000个自举程序中的任何一个中均不会对空中扩散距离产生重大影响，我们质疑这种解剖学特征作为空中扩散能力指标的用途。相反，DCM索引的修改版本与空中扩散距离（96％）一致。原始的SFP指数在100％的模型运行中具有显着影响，表明该指数非常适合作为欧洲EPT物种的空气扩散能力的指标。

通过提供有关该主题的经验数据的汇编，并在没有经验数据的情况下推荐一种准确的间接方法，本研究有助于评估欧洲EPT飞行距离。