Changes in river environments due to elevation gradients have a great impact on living organisms. In particular, with respect to aquatic insects, it has been recognized that even in closely related species there is a tendency for species to be replaced between upstream and downstream environments. Such a distribution tendency has also been suggested for the three species of the genus Ephemera of interest in this study. We used the “Megadata” on the distribution of each Ephemera mayfly species and comprehensively analyzed habitat information, GIS and data on multiple environmental factors. As a result, it became clear that environmental factors closely related to the altitudinal gradient were closely related to the distribution patterns of three Ephemera mayflies. In addition, we simulated how their distribution areas have changed due to Quaternary climate change cycles using the software M_AXENT. Although it was revealed that there were niche differentiations within the three Ephemera mayflies, there were overlaps in their respective preferred niche widths. Therefore, it is considered that the distribution pattern of the three Ephemera mayflies according to the altitudinal gradient represents mild niche differentiation, and also slight inter-species competition.

海拔梯度引起的河流环境变化对生物体有很大影响。特别地，对于水生昆虫，已经认识到即使在密切相关的物种中，也存在在上游和下游环境之间替换物种的趋势。在这项研究中，对于感兴趣的Ep属的三个物种也已经提出了这样的分布趋势。我们在每个Ep属”类的分布上使用了“ Megadata”，并综合分析了栖息地信息，GIS和有关多个环境因素的数据。结果，很明显，与海拔梯度密切相关的环境因素与三个Ep的分布模式密切相关。可能。此外，我们使用M _AXENT软件模拟了由于第四纪气候变化周期而导致其分布区域的变化。虽然据透露，有三个壁龛内分化蜉蝣蜉蝣，有在各自的利基首选宽度重叠。因此，可以认为，根据海拔梯度，三个Ep的分布模式代表了适度的生态位分化，也代表了轻微的种间竞争。