Native and introduced populations of Solidago gigantea differ in shoot production but not in leaf traits or litter decomposition

1. Invasive alien plants tend to have a greater specific leaf area and more nutrient-rich tissues than the invaded native vegetation. To test whether these traits differ between introduced and native populations of the same species, we compared 20 European (introduced) and 22 American (native) populations of Solidago gigantea Aiton (Asteraceae) in a common-garden experiment. 2. Five plants per population were grown for 2 years in pots and for one summer outdoors in nutrient-rich soil. We recorded shoot number and biomass, leaf production and senescence, flowering, leaf morphology and nutrient concentrations of leaves and litter. In laboratory assays, we compared litter decomposition and nutrient mineralization. 3. Shoot growth and leaf traits varied three- to 10-fold among the 42 populations. European plants produced, on average, more shoots than American plants, but did not differ in shoot size, leaf traits or litter decomposition. 4. The shoot number and total shoot biomass per plant in the experiment correlated positively with the number of new rhizomes produced by shoots of the same populations at their original field sites. 5. We conclude that introduced S. gigantea populations tend to produce more shoots through clonal growth than native populations. This may increase their ability to compete against the established vegetation in dense stands or at nutrient-poor sites.