Acacia longifolia, which is native to Australia, is a species which was cultivated in Portugal primarily to stabilize dunes and as an ornamental plant; now it has spread out uncontrollably in Portugal and into many ecosystems around the world. This has varying effects on native species. Because of a symbiosis with bacteria at its roots, Acacia longifolia can use atmospheric nitrogen from the air; it also grows fast and produces a lot of biomass. This means it adds nitrogen to the otherwise low-nutrient dune ecosystem, giving it unintended fertilizer. The acacia also uses more water than the native species. A team of researchers headed by the ecologists Professor Christiane Werner and Christine Hellmann, in collaboration with scientists at the Universities of Münster and Hamburg, has worked out a new approach to determine the extent to which the physical surroundings influence the acacia’s interaction with other plants.