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Phenotypic plasticity is commonly considered as a trait associated with invasiveness in alien plants because it may enhance the ability of plants to occupy a wide range of environments. Although the evidence of greater phenotypic plasticity in invasive plants is considerable, it is not yet conclusive. We used a meta-analysis approach to evaluate whether invasive plant species show greater phenotypic plasticity than their native or non-invasive counterparts. Th e outcome of such interspecifi c comparisons may be biased when phylogenetic relatedness is not taken into account. Consequently, species pairs belonged to the same genus, tribe or family. Th e meta-analysis included 93 records from 35 studies reporting plastic responses to light, nutrients, water, CO 2 , herbivory and support availability. Contrary to what is often assumed, overall, phenotypic plasticity was similar between invasive plants and native or non-invasive closely related species. Th e same result was found when separate analyses were conducted for trait plasticity to nutrients, light and water availability. Th us, invasive plant species and their native or non-invasive counterparts are equally capable of displaying functional responses to environmental heterogeneity. Th e colonization of a wide range of environments by invasive plants could be due to their capacity to undergo adaptive ecotypic diff erentiation rather than to their ability to display plastic responses. Alternatively, phenotypic plasticity might play a role in plant invasion, but only during the initial phases, when tolerance of the novel environment is essential for plant survival. Afterwards, once alien plants are identifi ed as invaders, the magnitude of phenotypic plasticity might be reduced after selection of the optimum phenotypes in each habitat. Th e identifi cation of plant traits that consistently predict invasiveness might be a futile task because diff erent traits favor invasiveness in diff erent environments. Approaches at the local scale, focusing on the ecology of specifi c invasive plants, could be more fruitful than global macro-analyses. |
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