Poster, Macroecology and Biogeography 2023, SWO-Tagungszentrum, Campus: 04.05.2023 - 05.05.2023
Abstract:
In island radiations, the evolution of secondary (insular) woodiness and the rapid diversification of species show intriguing parallels between oceanic islands and tropical alpine sky islands. We explore the evolutionary dynamics of species diversification and trait disparification across evolutionary radiations in contrasting island systems compared with their non-island relatives. We estimate rates of species diversification, growth form evolution, and phenotypic space saturation for the classical oceanic island plant radiations – the Hawaiian silverswords and Macaronesian Echium – and the well-studied sky island radiations of Lupinus and Hypericum in the Andes. Our results show that secondary woodiness is associated with dispersal to islands and with accelerated rates of species diversification, accelerated disparification of plant growth forms, and occupancy of greater phenotypic trait space for island clades than their non-island relatives, on both oceanic and sky islands. We conclude that secondary woodiness is an enabler trait, manifested as the potential to occupy greater trait space, for general plant radiations on island systems. This further emphasizes the importance of combinations of clade-specific traits and ecological opportunities in driving adaptive radiations.