Population genetics across aquatic species: evolutionary history, phylogeography, and taxonomic complexity

This doctoral thesis investigates genetic diversity, population structure, and evolutionary dynamics of aquatic species across marine and freshwater systems through population genetic approaches. By integrating phylogenetics, phylogeography, and molecular taxonomy, four case studies were conducted on native and invasive species under distinct ecological contexts. The results provide insights into the complex interplay among evolutionary history, invasion dynamics, taxonomic complexity, and population connectivity and dispersal, highlighting the role of historical and contemporary factors in shaping genetic differentiation. Particular attention is given to processes including demographic decline, habitat fragmentation, and biological invasions, which represent major challenges for aquatic biodiversity. This research contributes to the understanding of evolutionary resilience, diversification, and adaptation in aquatic environments and highlights the role of population genetics as a unifying framework for interpreting evolutionary processes. Additionally, the findings offer relevant information to support biodiversity monitoring, management and conservation strategies.