Supplementary material from "The macro-eco-evolutionary interplay between dispersal, competition, and landscape structure in generating biodiversity"

Theory links dispersal and diversity, predicting highest diversity at intermediate dispersal levels. However, the modulation of this relationship by macro-eco-evolutionary mechanisms and competition within a landscape is still uncertain. We examine the interplay between dispersal, competition, and landscape structure in shaping biodiversity over 5 million years in a dynamic archipelago landscape. We model allopatric speciation, temperature niche, dispersal, competition, trait evolution and trade-offs between competitive and dispersal traits. Depending on dispersal abilities, our archipelago exhibits two “connectivity regimes”, each potentially fostering speciation events between the same group of islands. Peaks of diversity (i.e. alpha, gamma, and phylogenetic), occurred at intermediate dispersal and competition shifted diversity peaks towards higher dispersal values for each connectivity regime. This shift demonstrates how competition can boost allopatric speciation events through the evolution of thermal specialists, ultimately limiting geographical ranges. Even in a simple landscape, multiple intermediate dispersal diversity relationships emerged, all shaped similarly and according to dispersal and competition strength. Our findings remain valid as dispersal- and competitive-related traits evolve and trade-off; potentially leaving identifiable signals, particularly when trade-offs are imposed. Overall, we underscore the convoluted relationships between dispersal, species interactions and landscape structure on macro-eco-evolutionary processes, with lasting imprints on biodiversity.