Islands have long been recognized as key contributors to biodiversity because islands facilitate geographic isolation and ecological divergence from mainland ancestors. However, island colonization has traditionally been considered an evolutionary dead-end process, and its consequences for continental biodiversity remain understudied. Here, we studied the evolutionary radiation of Columbiformes (i.e. pigeons and doves) to examine if ecological niche shifts on islands shaped biological diversification and community composition on continents. We show that the colonization of islands by continental, terrestrial-foraging lineages led to exploitation of a new ecological niche (i.e. arboreal foraging). This transition towards arboreal foraging was associated with evolutionary adaptation towards a new morphological optimum. In addition, arboreal-foraging lineages experienced an increase in speciation rates, which was associated with successful range expansions to other islands as well as back-colonization of continents. Our results provide empirical evidence that diversification on continents can only be fully understood when studying the diversification processes that took place on islands, challenging the view of islands as mere sinks of evolutionary diversity.

Files included:

ColumbidaeTraits.csv

The dataset includes a list of 214 species of Columbiformes for which morphological, ecological and genetic data are available. Morphological data include wing, tail, tarsus and bill length (mm) as well as body mass (g). Ecological data includes foraging behaviour (A=arboreal vs T=Terrestrial), habitat type (F=Forest vs O=Open) and island dwelling (C=Continent vs I=Island). The combination of foraging, habitat and island variables define the ecoGroup variable, consisting in five categories (AFI, AFC, TFC, TFI, TOC). The mophological data is log-transformed.

Columbidae100phylo.tre

A random sample of 100 phylogenetic trees from the posterior distribution, including the 214 species of Columbiformes included in this study.