Invasion of sandy beachfronts by ornamental plant species in Queensland
George N. Batianoff and Andrew J. Franks, Queensland Herbarium, Department of Environment, Indooroopilly, Queensland 4068, Australia.
This study encompasses the east coast of Queensland from the Gold Coast to Thursday Island. Data were derived from both past and recent coastal studies (1980-1997) by the senior author, herbarium records and through liaison with field officers. The ornamental vascular plants recorded as invasive weeds along the sandy beachfronts of Queensland include 103 species belonging to 48 families and 88 genera. Herbaceous lifeforms and succulence are frequent characteristics of invasive ornamental species along these sandy shores.
An increase in the proportion of weeds of sandy beachfronts from north to south along the east coast of Queensland is reported. This distribution is possibly associated with human population densities rather than climatic conditions. In this study the most important factors contributing to ornamental weed invasions are human assisted plant introductions through the dumping of garden plants into native vegetation. The most abundant invasive ornamental weeds of Queensland beachfronts are Agave spp. (sisal or agave), Asparagus densiflorus (asparagus fern), Bryophyllum spp. (mother-of-millions), Catharanthus roseus (pink periwinkle), Euphorbia cyathophora (dwarf poinsettia), Gloriosa superba (glory lily), Lantana camara (lantana), Opuntia stricta (prickly pear), Sanseviera trifasciata (mother-in-law's tongue), Schinus terebinthifolia (Brazilian pepperina tree) Senna pendula var. glabra (Easter cassia) and Wedelia trilobata (Singapore daisy). The proportion of naturalized exotic species of the Queensland sandy beachfront flora is three times greater than the state average.
To prevent the further degradation of beachfront vegetation and the possible loss of native species richness through weed encroachment, urgent action is required. We recommend restoration of affected beachfronts through removal of invasive ornamental weed species and replanting with indigenous seashore species. Education, policing and 'polluter pays' fines are also seen as a method of weed management along sandy beachfront areas of Queensland.
Plant Protection Quarterly (1997) 12 (4) 180-186.