Dispersal syndrome evolution in angiosperms: ancestral zoochory, correlations with pollination mode and biome, and sampling effects

- Aim: Angiosperms have evolved a diverse range of seed dispersal syndromes that have undoubtedly played a key role in their evolutionary history and rise to dominance. However, it remains largely unknown how ancestral angiosperm seeds were dispersed, whether dispersal syndromes are associated with biome and pollination mode transitions, and how sampling and syndrome assignment affect historical inferences at the angiosperm-wide scale. - Location: Global - Time period: Cretaceous - Cenozoic - Major taxa studied: Angiosperms - Methods: We integrated a large phylogeny with a high quality dispersal-related trait and syndrome dataset for >1200 species representing all extant angiosperm families. We used phylogenetic comparative methods to infer ancestral states of major angiosperm clades and evolutionary correlations between dispersal syndromes, biomes and pollination modes. In addition, we used taxon removal simulations to assess how sampling affects ancestral state and transition rate inferences. - Results: We show that angiosperms were ancestrally most likely animal-dispersed (zoochory), with fleshy, indehiscent fruits. Over macroevolutionary time, frequent transitions between dispersal syndromes occurred, with non-specialised (autochorous) dispersal as an intermediate state between transition from animal (zoochory) to wind (anemochory) dispersal. Furthermore, we found that zoochory was associated with increased evolutionary transitions to tropical biomes and to biotic pollination, and abiotic dispersal to cold or arid biomes and to abiotic pollination. Taxon removal up to 50% showed minimal effects on ancestral state and transition rate inferences. - Main conclusions: The progressive evolution of diaspore complexity may have facilitated the frequent and repeated transition between dispersal syndromes, critical for the colonisation and exchange of angiosperms across modern biomes, and present-day associations between biotic and abiotic pollination and seed dispersal.