PDF(Pubmed)
Abstract：
Niche differentiation between closely related species leads to differentiation of their habitats. Segregation based on slight differences in environmental factors, that is niche differentiation on the microhabitat scale, allows more species to inhabit a certain geographic space. Therefore, such fine scale niche differentiation is an important factor in the support of species diversity. In addition, niche differentiation on the microhabitat scale and/or the differentiation of breeding seasons can be considered typical mechanisms that facilitate multispecies\' co-existence. In this study, sister species (Commonly, Ephemera japonica inhabit at upstream region and Ephemera strigata inhabit at middle stream region), which often coexist in the upper to middle reaches of river systems of the Japanese Islands, were targeted and the following aspects were investigated. First, differences in habitat preference and interspecific differences in flow distribution patterns on a geographically fine scale were tracked in detail. Subsequently, the temporal transitions of their distribution patterns were investigated in detail and seasonal changes were investigated. Finally, we thoroughly investigated the disappearance of nymphs of each species from the river due to emergence affected the distribution of each species (by conducting daily emergence surveys). Combining results of these multiple studies also suggested that there may be spatiotemporal interspecial interaction between these two species within/around their overlapping regions. Traditionally, the longitudinal distribution pattern of these two Ephemera mayflies has been thought to be established based on a difference in habitat preferences, but this study revealed that the interspecific interaction between the two species also plays an important role. This study provides new insights into species diversity and distribution pattern formation in river-dwelling species.
摘要：
密切相关的物种之间的生态位差异导致其栖息地的差异。根据环境因素的细微差异进行隔离，也就是微生境尺度上的生态位分化，允许更多的物种居住在一定的地理空间。因此,这种精细尺度的生态位分化是支持物种多样性的重要因素。此外,微生境尺度上的生态位分化和/或繁殖季节的分化可以被认为是促进多物种共存的典型机制。在这项研究中,姐妹物种(通常，海象栖息在上游地区,纹状海象栖息在中流地区),经常在日本群岛的中上游河流系统中共存，有针对性地对以下几个方面进行了调查。首先,详细跟踪了地理尺度上栖息地偏好的差异和流量分布模式的种间差异。随后，详细研究了其分布模式的时间转变，并调查了季节变化。最后,我们彻底调查了由于出苗影响每个物种的分布而从河流中消失的每个物种的若虫（通过进行每日出苗调查）。综合这些多项研究的结果还表明，这两个物种在其重叠区域内/周围可能存在时空间相互作用。传统上,这两种天象may的纵向分布模式被认为是基于栖息地偏好的差异而建立的，但是这项研究表明，两种物种之间的种间相互作用也起着重要作用。这项研究为河流居住物种的物种多样性和分布格局形成提供了新的见解。
