Pohe Stephen R, Winterbourn Michael J, Harding Jon S
School of Biological Sciences, University of Canterbury, Christchurch 8140, New Zealand.
Pohe Environmental, Whangarei 0112, New Zealand.
Insects. 2024 Sep 29;15(10):757. doi: 10.3390/insects15100757.
The distribution of species in relation to latitude and altitude is of fundamental interest to ecologists and is expected to attain increasing importance as the Earth's climate continues to change. Species diversity is commonly greater at lower than higher latitudes on a global scale, and the similarity of communities frequently decreases with distance. Nevertheless, reasons for such patterns are not well understood. We investigated species richness and changes in community composition of mayflies (Ephemeroptera) over 13 degrees of latitude at 81 locations throughout New Zealand by light-trapping and the benthic sampling of streams. Mayflies were also sampled along an altitudinal gradient on a prominent inactive volcano in the east of North Island. Sampled streams were predominantly in the native forest, at a wide range of altitudes from sea level to c. 1000 m a. s. l. A total of 47 of the 59 described New Zealand mayflies were recorded during the study, along with five undescribed morphospecies. Species richness declined and the degree of dissimilarity (beta diversity) of mayfly communities increased significantly from north to south but less strongly with increasing altitude. Our results suggest that the southward decline in species richness has historical origins with the north of the country having acted as a major refuge and region of speciation during the Pleistocene. The increasing dissimilarity of the northern and southern communities may reflect an increasingly harsh climate, variable amounts of subsequent southward dispersal of northern species and, in the South Island, the presence of species which may have evolved in the newly uplifted mountains during the Miocene-Pliocene.
物种在纬度和海拔上的分布是生态学家们极为感兴趣的基本问题，并且随着地球气候持续变化，预计其重要性会日益增加。在全球范围内，通常低纬度地区的物种多样性高于高纬度地区，而且群落的相似性常常随距离增加而降低。然而，对于这些模式形成的原因，人们尚未完全理解。我们通过灯光诱捕和对溪流的底栖生物采样，在新西兰各地的81个地点，跨越13个纬度调查了蜉蝣目（Ephemeroptera）的物种丰富度以及群落组成的变化。我们还沿着北岛东部一座著名的休眠火山的海拔梯度对蜉蝣进行了采样。采样的溪流主要位于原生森林中，海拔范围广泛，从海平面到海拔约1000米。在这项研究中，共记录了新西兰已描述的59种蜉蝣中的47种，以及5个未描述的形态物种。蜉蝣群落的物种丰富度从北向南显著下降，且随着海拔升高下降幅度较小，但群落的差异程度（β多样性）显著增加。我们的研究结果表明，物种丰富度的向南递减具有历史根源，该国北部在更新世期间曾是主要的避难所和物种形成区域。南北群落差异的不断增加可能反映出气候日益恶劣、北方物种随后向南扩散的数量不同，以及在南岛存在可能在中新世 - 上新世期间在新隆起的山脉中进化而来的物种。
