Weiss Martina, Brasseur Marie V, Lorenz Armin W, Leese Florian
Aquatic Ecosystem Research University of Duisburg-Essen Essen Germany.
Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen Essen Germany.
Ecol Evol. 2025 Apr 24;15(4):e71214. doi: 10.1002/ece3.71214. eCollection 2025 Apr.
Urbanization and the resulting modifications of freshwater ecosystems can play an important role in shaping metapopulation structure and dynamics of aquatic organisms. Ecological restoration aims at improving river ecosystems by reducing or removing anthropogenic stressors and habitat fragmentation, facilitating natural dispersal among population patches. However, the success of such ecological restoration measures is not guaranteed, and for many of the functionally important but smaller organisms, improved connectivity is difficult to assess. Here, genetic markers can help in assessing small-scale connectivity and in identifying persisting gene flow barriers. In this study used high-resolution genetic markers to study the metapopulation structure of two ecologically important amphipod species, and , in the heavily urbanized Emscher catchment in Germany. This catchment was strongly degraded and polluted for over a century but has been restored over the past two decades. For both strictly aquatic species, we analyzed mitochondrial cytochrome c oxidase I (COI) gene sequences as well as nuclear genome-wide single nucleotide polymorphism (SNP) data. We detected strong metapopulation structure within both species, which was mainly driven by catchment affiliation, wastewater, large in-stream barriers, and recent recolonization of restored stream sections. However, population structure was not fully explained by these factors, indicating that eco-evolutionary factors such as priority effects, adaptation, or biotic interactions play a role in shaping the population structure. Furthermore, our data show a strong mito-nuclear discordance for both species with regard to detailed population structure and also the presence of possible cryptic species for . Here, nuclear data indicate that the diverging mitochondrial lineages of (Gp-C and Gp-E) represent only one species in this region. Our study shows how genetic markers can support the assessment of population connectivity and thus evaluate the success of ecological restoration.
城市化以及由此导致的淡水生态系统变化，在塑造水生生物集合种群结构和动态方面可能发挥重要作用。生态修复旨在通过减少或消除人为压力源和栖息地破碎化，促进种群斑块间的自然扩散，从而改善河流生态系统。然而，此类生态修复措施的成功并无保障，对于许多功能重要但体型较小的生物而言，改善连通性难以评估。在此，遗传标记有助于评估小规模连通性，并识别持续存在的基因流动障碍。在本研究中，我们使用高分辨率遗传标记，研究了德国高度城市化的埃姆斯河集水区内两种具有重要生态意义的双足类物种（物种名缺失）的集合种群结构。该集水区在过去一个多世纪里严重退化和污染，但在过去二十年中已得到修复。对于这两种严格水生的物种，我们分析了线粒体细胞色素c氧化酶I（COI）基因序列以及全基因组范围的核单核苷酸多态性（SNP）数据。我们在两个物种中均检测到强烈的集合种群结构，其主要由集水区归属、废水、大型河道障碍物以及恢复河段的近期重新定殖驱动。然而，这些因素并未完全解释种群结构，这表明诸如优先效应、适应或生物相互作用等生态进化因素在塑造种群结构中发挥了作用。此外，我们的数据显示，这两个物种在详细种群结构方面存在强烈的线粒体 - 核不一致性，并且（物种名缺失）可能存在隐存物种。在此，核数据表明，（物种名缺失）不同的线粒体谱系（Gp - C和Gp - E）在该区域仅代表一个物种。我们的研究表明遗传标记如何能够支持对种群连通性的评估，从而评估生态修复的成功与否。
