Plant colonization across the Galápagos Islands: success of the sea dispersal syndrome

A new approach for investigating evidence for the capacity of plant colonization between islands and the success of plant morphological traits associated with seed dispersal is presented. As colonization is the result of dispersal and establishment, oceanic archipelagos provide an ideal spatio-temporal system in which to analyse plant dispersal traits related to current distributions of species across islands. The Galápagos archipelago comprises 12 islands> 10 km2 that harbour 403 native angiosperms, of which 313 native species occupy lowland habitats that are present on all islands. We inferred the minimum number of colonization events within the archipelago for the species (289 lowland species) present on more than one island (floristic analysis). The distribution (number of islands) of species across the islands was slightly left-skewed, with 58 % of all lowland species being present on one to six islands. The success of dispersal syndromes (i.e. morphological trait sets of the diaspores associated with dispersal) favourable to inter-island dispersal (medium-distance dispersal, MDD) was also analysed (syndrome analysis). In particular, the 289 lowland species were classified into four dispersal groups (syndromes): sea (thalassochory), wind (anemochory), and animal interior (endozoochory) or animal exterior (epizoochory). Most species (N = 174, 55.6%), however, displayed no traits related to MDD (unspecialized diaspores). Analyses of the distribution of syndrome traits across the 289 lowland native species and 12 islands revealed that: (1) species with one or more of the four MDD syndromes did not have broader distributions than those with unspecialize