Vegetation change on an urban coastal dune system

Coastal environments, not directly transformed by urbanisation but within an urban matrix, can be transformed by changes in climate, invasive species and plantings. We assess changes in vegetation structure since European settlement and changes in native species abundance since 2003 on the cuspate dune complex at Lower Sandy Bay, Tasmania. The pre-European vegetation of the cuspate forehead seems likely to have been grassland dominated by Spinifex sericeus and Austrofestuca littoralis on the foredunes and Eucalyptus viminalis open-forest with a shrubby to grassy understorey on the older dunes. Some trees of E. viminalis still occur on the dune system, together with many elements of the original understorey. The foredune native vegetation had been replaced by Ammophila arenaria closed-grassland by 2003. Much of this grassland was invaded by the native shrub, Acacia longifolia, by 2017. Between 2003 and 2017 almost all native shrub species increased in abundance. Succulent, grass and herb species suffered decline. Increased competition with exotic species, changes in disturbance regimes and decreases in fire frequency in the coastal area are most likely to have influenced the changes in native species distributions.