Tree invasions of Mediterranean‐climate ecosystems pose a significant threat to both biodiversity and functioning, by excluding native species, altering soil nutrient status and depleting water resources. In order to attain greater relative biomass associated with successful invasion in these characteristically resource‐poor environments, invasive species must have novel traits that enable better acquisition (e.g. deep roots) or exploitation of different resources (e.g. N2 fixation) and/or more efficient use of available resources than native species. We compared the ecophysiological and morphological traits of three abundant native species to those of the invasive Australian tree species,
Acacia cyclops. This species is widely invasive in the Mediterranean‐climate coastal vegetation of South Africa that includes the Strandveld vegetation type. A. cyclopshad 30–50% greater foliar N concentrations ( P< A. cyclopsmaintained higher photosynthetic rates over the dry summer season ( ca. 15 μmol m−2 s−1) than the native species. These higher photosynthetic rates may result from sustained access to water due to deeper rooting abilities as indicated by the more negative δD values ( P< A. cyclops(−43‰) in comparison with the some native species (−29 to −37‰). Acacia cyclopsdid not, however, exhibit greater water use efficiencies or photosynthetic nitrogen use efficiencies ( P> A. cyclopsinto this resource‐limited Mediterranean‐climate ecosystem appears to be supported by greater resource acquisition, possibly partially through N2 fixation and greater rooting depth, rather than greater resource use efficiency or conservation.