Historical Imprints and Future Shifts: Evolutionary Biogeography of Atlantic Reef Fishes Under Climate Change

Abstract

Aim To incorporate phylogenetic relationships into Atlantic marine biogeography, investigating how evolutionary history and environmental conditions interact to shape biodiversity patterns at ocean‐basin scales, and to assess how phylogenetic metrics can inform predictions of ecological vulnerability under climate change. Location Atlantic Ocean. Time Period Last glacial maximum to 2100. Major Taxa Studied Reef‐associated ray‐finned fishes. Methods We integrated the distributions of 1637 species with detailed phylogenetic information to delineate phylogenetically informed bioregions (“phyloregions”). Using phylogenetic diversity, endemism, and evolutionary distinctiveness, we quantified large‐scale evolutionary patterns and applied machine‐learning models with climate projections to forecast future changes in biodiversity structure, including alpha‐ and beta‐diversity metrics and thermal niche breadth. Results We delineated 19 distinct phyloregions, shaped mainly by past isolation and major oceanographic barriers. Evolutionary distinctiveness was highest in temperate transition zones and remote oceanic islands, while tropical regions emerged as hotspots of phylogenetic diversity and endemism. Future climate scenarios indicate rising phylogenetic diversity and endemism in tropical areas, likely reflecting lineage mixing and range shifts, alongside narrowing thermal niche breadths that signal reduced ecological adaptability. Main Conclusions The delineation of Atlantic phyloregions reveals how evolutionary legacies, historical climatic dynamics, and major oceanographic barriers have shaped reef fish diversity at ocean‐basin scales. Temperate transition zones and remote oceanic islands harbour highly distinct evolutionary lineages, while tropical regions concentrate phylogenetic diversity and endemism. Coupling this bioregionalization framework with future climate projections further suggests that warming may reorganize assemblage composition and narrow thermal niche breadths across the Atlantic. Together, these findings provide a scalable framework for integrating evolutionary history into conservation prioritization and improving our understanding of biodiversity dynamics under global change.

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