Revista Chilena de Historia Natural 84 (4): 543-552, 2011
RESEARCH ARTICLE
Darwin’s Naturalization Hypothesis assessed in the alien flora of continental
Chile
The Darwin’s Naturalization Hypothesis (DNH) states that the successful
naturalization of alien species is favored when the phylogenetic relationship between the colonizer and the recipient
community is distant. Conversely, related species would compete strongly, hence reducing the probability of naturalization.
From a populational perspective, the concept of naturalization involves both the progressive increase in size and spatial
distribution of the invasive population. In this study, we focused our attention on the spatial component of naturalization,
assessing the role of phylogenetic relatedness as a determinant of its extension. Following the DNH, it is expected that
those alien species closely related to the native flora would show narrower distribution ranges than alien taxa less related to
native species. Using the APG III taxonomic system as an indicator of phylogenetic relationships in the vascular flora of
continental Chile, our analysis showed that alien species with congeneric native counterparts have larger ranges than alien
species with a distant relationship (i.e. species belonging to families or orders not represented in the native flora). These
results do not support the DNH because the more distant taxa (less related species) show distributional ranges smaller.
Results suggest that close relatedness could have facilitated the naturalization of alien plants in continental Chile, at least
for species belonging to genus and families represented on the native flora.
Key words:
alien flora,
biological invasion, geographic range, native flora, phylogenetic relatedness
