Microsatellite datasets in Genepop format:The first dataset includes 1,021 genotypes, uncorrected for repeated multilocus genotypes (MLGs).The second dataset contains 912 distinct MLGs, representing one unique multilocus genotype per individual.

Canopy-forming seaweeds, especially fucoids (Fucales, Phaeophyceae), constitute marine forests in the Mediterranean Sea that deliver key ecosystem services. However, escalating human pressures in coastal areas have led to habitat fragmentation, significantly impacting the dynamics of gene flow and evolutionary trajectories. In this study, we investigated population connectivity among 43 sites hosting Ericaria amentacea situated in the northwestern Mediterranean Sea. By integrating microsatellite genotyping and biophysical modelling, we aimed to evaluate the hypothesis that population connectivity is approximated by oceanographic connectivity, rather than coastal distance. While traditional approaches to oceanographic connectivity had focused on single-generation dispersal models, we adopted a multigeneration perspective. This involves employing a biophysical model that considers gene flow through multiple stepping-stones populations across the E. amentacea distribution and over distinct generations of dispersal. Using distance-based redundancy analysis (db-RDA), we found that multi-generation dispersal significantly contributes to genetic differentiation, surpassing the influence of coastal distance. Even so, genetic differentiation remained significant among all population pairs, suggesting that gene flow may be hindered by differential selection acting against migrants and/or obscured by the effects of local genetic drift. The latter is likely, given the species' low dispersal potential and self-compatibility, both of which promote small, spatially restricted breeding units. In addition, our results emphasized that oceanographic connectivity promoted long-distance dispersal across northern Corsica and Eastern Provence over a single generation throughout the drifting of fertile thalli, which might have contributed to moderate differentiation between local populations. Overall, this pilot framework highlights the value of considering multi-generation dispersal across numerous intermediate stepping-stones for informing management strategies aimed at enhancing population connectivity and safeguarding genetic diversity in seaweeds.

形成冠层的海藻（canopy-forming seaweeds），尤其是墨角藻类（fucoids，褐藻纲墨角藻目（Fucales, Phaeophyceae）），在地中海构建了海洋森林，提供关键的生态系统服务功能。然而，沿海区域不断加剧的人类活动压力已导致生境破碎化，显著影响了基因流动态与演化轨迹。
本研究针对地中海西北部海域内43个分布有围小网衣藻（Ericaria amentacea）的样地开展种群连通性调查。研究整合微卫星基因分型技术与生物物理建模，旨在验证“种群连通性可通过海洋连通性而非沿海距离进行近似表征”这一假说。过往针对海洋连通性的传统研究多聚焦于单世代扩散模型，而本研究采用多世代视角：即借助生物物理模型，考量Ericaria amentacea分布范围内多个踏脚石种群间跨世代的基因流扩散过程。
通过基于距离的冗余分析（distance-based redundancy analysis, db-RDA），本研究发现多世代扩散对遗传分化的贡献显著高于沿海距离的影响。尽管如此，所有种群对间的遗传分化仍显著存在，这表明基因流可能受到针对迁移个体的差异化选择的阻碍，或因局域遗传漂变效应而被掩盖。鉴于该物种兼具低扩散潜能与自交亲和性，二者均会促进形成空间受限的小型繁殖单元，后一种可能性更大。
此外，研究结果表明，在单世代的具繁殖能力的叶状体（fertile thalli）漂流过程中，海洋连通性可推动科西嘉岛北部与普罗旺斯东部区域实现长距离扩散，这或促成了局域种群间的中等程度分化。
总体而言，本试点研究框架凸显了考虑跨多个中间踏脚石种群的多世代扩散的价值，可为旨在提升海藻种群连通性、保护遗传多样性的管理策略提供科学参考。