Functional traits of common New Zealand foredune species at New Brighton, Canterbury

© 2014 The Royal Society of New Zealand. The introduction of exotic plant species to the sand dunes of New Zealand has displaced native dune species. To examine our hypotheses that: (1) exotic species have functional traits that allow them to outcompete native species; and (2) that traits of exotic species vary across the dune environment, we measured specific leaf area, leaf dry matter content, leaf area and plant height in five common fore-dune taxa of New Brighton, Christchurch. The native species Spinifex sericeus, Ficinia spiralis and Poa billardierei had traits indicative of a more conservative growth strategy compared with the exotic tussock grass Ammophila arenaria and the exotic succulent Carpobrotus spp., suggesting that natives would be less competitive. In exotics, leaf size was larger at greater distances from the high tide mark, as was plant height in A. arenaria. These differences in traits across the dune environment point to phenotypic plasticity across short, but sharp, environmental gradients