XVI International Botanical Congess
Molecular studies on the evolution of red algal species and genera show that geographic distribution patterns have been shaped by vicariant events (through continental drift), dispersal events, and environmental constraints set by present and past climatic limits. Old vicariant patterns may still be recognized in tropical species (Tethys imprint).In temperate species, palaeoclimatic change through glacial/interglacial cycles has been of major importance. By superimposing ecophysiological traits (thermal limits for life history processes) onto phylogenetic trees, the evolution of these traits may be reconstructed. Although some local adaptation may occur, phylogenetic constraints, reflecting adaptations to past conditions, are strong. These constraints contribute to the maintenance of thermal barriers at geographic boundaries.