A phylogenetic comparative study of preadaptation for invasiveness in the genus Silene (Caryophyllaceae)
2011
Jenkins, Christina | Keller, Stephen R.
The role of preadaptation in ecology and evolution is determined by how the traits evolved by a species in one environment allow it to be successful in novel environments. This concept bears directly on modern biological invasions, as species are introduced to new locations beyond their historical borders. In this study, we used a phylogenetically-controlled analysis of the flowering plant genus Silene (Caryophyllaceae) to show that native geographic range size, along with a suite of life history traits affecting plant growth and reproduction, have preadapted some species for the invasion of new ranges. Using a path analytic approach, we further show that some of the covariance between life history traits and invasiveness is indirect, caused by mutual associations with native range size. Specifically, we found that reproductive traits such as the number of flowers per inflorescence and length of the flowering season directly preadapt species for invasion, while plant height is indirectly associated with invasion through a correlation with native range size. Other traits such as ovule number and leaf size are both directly and indirectly associated with invasion success. Our results reveal the importance of accounting for correlations among plant traits and geographic range size when predicting preadaptation for invasiveness. We also highlight that the traits predictive of invasion success among species of Silene are often those found to be rapidly evolving within introduced populations, suggesting common forces of selection operating at these different biological scales of organization during invasion.
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