From gardens to forests: successful invasion of Japanese Mock Orange (Pittosporum tobira, Pittosporaceae) in the Llobregat Delta (NE Iberian Peninsula)

Abstract

Plant invasions are recognized as a threat to the worlds biodiversity, being particularly hard to supress its ecological and socio-economic impacts once an species establishes viable populations in a given locality. Prior knowledge about the potential of allochthonous plants to become invasive is essential to design adequate management policies. Here we present a study-case where an allochthonous plant the Japanese Mock Orange, Pittosporum toriba has established large populations in forests of a coastal wetland of Catalonia. Our work has geolocated more than 1000 individuals in natural and semi natural habitats. The species has become a widespread shrub in the understory of studied woods. We discuss the landscape properties that likely promoted such a successful invasion and the management possibilities. The invasive potential of plants as the Japanese Mock Orange should be reconsidered while such ornamentals are changing autochthonous flora communities.