Julia Dupin
Université Paul Sabatier, France.
Historical biogeography and the evolution of environmental niche in Datureae (Solanaceae)
Distributions of plant clades are shaped by abiotic and biotic factors as well as historical aspects such as center of origin. Dispersals between areas may lead to niche evolution when lineages are established in new environments. Alternatively, dispersing lineages may exhibit niche conservatism, moving between areas with similar environments. Here we tested these contrasting hypotheses in Datureae. We estimated the ancestral range of Datureae along with its historical biogeography, then characterized the environmental niche of each taxon using climatic and soil variables and tested for shifts in niche optima. Finally, we examined how these shifts relate to the niche breadth of taxa and the degree of overlap between them.
Datureae originated in the Andes and subsequently expanded its range to North America and non-Andean regions of South America. The ancestral niche, and that of most Datura and Trompettia species, is dry, while Brugmansia species likely shifted toward a more mesic environment. The expansion of Datureae into North America was associated with niche conservatism, with dispersal into similarly dry areas as occupied by the ancestral lineage. Subsequent niche evolution diversified the range of habitats occupied by species in Datureae but also led to significant niche overlap among the three genera.
23 сен 2024
