Résumé
The tropical Andes of South America, the world’s richest biodiversity
hotspot, are home to many rapid radiations. While geological, climatic,
and ecological processes collectively explain such radiations, their
relative contributions are seldom examined within a single clade. We
explore the contribution of these factors by applying a series of
diversification models that incorporate mountain building, climate change,
and trait evolution to the first dated phylogeny of Andean bellflowers
(Campanulaceae: Lobelioideae). Our framework is novel for its direct
incorporation of geological data on Andean uplift into a macroevolutionary
model. We show that speciation and extinction are differentially
influenced by abiotic factors: speciation rates rose concurrently with
Andean elevation, while extinction rates decreased during global cooling.
Pollination syndrome and fruit type, both biotic traits known to
facilitate mutualisms, played an additional role in diversification. These
abiotic and biotic factors resulted in one of the fastest radiations
reported to date: the centropogonids, whose 550 species arose in the last
5 Myr. Our study represents a significant advance in our understanding of
plant evolution in Andean cloud forests. It further highlights the power
of combining phylogenetic and Earth science models to explore the
interplay of geology, climate, and ecology in generating the world’s
biodiversity.