Daptive plasticity to heterogeneous environments increases capacity for division of labor in the clonal invader Carpobrotus edulis (Aizoaceae)

Abstract

Premise of the study: Clonality has been proposed as an important mechanism favoring plant invasions, but few studies have been conducted to determine the role of clonal traits on successful invaders. An interesting trait associated with clonality is the capacity for division of labor. Division of labor requires a negative spatial correlation between the availabilities of two essential resources and ramet specialization for locally abundant resources to increase the overall performance of the clone. We hypothesized that the capacity for division of labor in the clonal invader Carpobrotus edulis will be selected in those clones from patchy environments where this trait could be an advantage. Methods: Morphological and physiological division of labor was compared between clones from coastal sand dunes (where nutrients and light show a negative spatial covariance) and from rocky coasts (where nutrients and light are homogenously distributed). Key results: Clones from coastal sand dunes showed a greater capacity than clones from rocky coasts for division of labor. Specialization for abundance was found at the morphological (biomass allocated to roots) and the physiological (photochemical efficiency) level. Conclusions: The greater ability for division of labor in the patchy environment where the presence of this trait would be more beneficial demonstrates the existence of local adaptation and suggests that rapid evolution in clonal traits could be contributing to the success of the invader C edulis. This study is one of the few showing that division of labor is under selection and is the first reporting adaptive division of labor of an aggressive invader. © 2014 Botanical Society of America.