Leaf functional traits and insular colonization: subtropical islands as a melting pot of trait diversity in a widespread plant lineage

Aim: One of the main goals of functional biogeography is to examine distribution patterns of trait diversity, and islands provide excellent study cases for this emerging field. We tested the hypothesis that multiple dispersals from a common mainland pool would promote functional similarity among island systems when environmental conditions are similar, but also novel phenotypic traits related to colonization history and exploitation of new habitats.

Location: Mediterranean Basin and Macaronesian islands

Methods: We used the well-known biogeographical history of a woody plant complex (Periploca laevigata s.l.) to examine trait variation and how it relates to climatic conditions of mainland and subtropical island settings. In a common garden experiment, we measured a suite of leaf physiological and anatomical traits tightly related to plant performance in 320 seedlings representing 21 populations of five sublineages: the oldest (2.6 my) island colonization (western Canary Islands) a...