marram grass

Desmoschoenus spiralis displacement by Ammophila arenaria: the role of drought

The exotic sand-binder Ammophila arenaria (marram grass) has displaced the native sedge Desmoschoenus spiralis (pingao or pikao) from many of New Zealand’s coastal dunes. This study explores the possible role of drought as a mechanism promoting marram invasion and pingao displacement. The response of the two sandbinders to conditions of increasing soil water deficit was compared in a four-week pot trial. Water potential, relative water content and stomatal conductance were measured every 3–4 days on randomly selected individuals from a control and two drought treatments.