Primary vegetation development on the sand spit of Shallow Inlet, Wilsons Promontory, southern Victoria

spit was colonised in the 1960s by the exotic grasses *Thinopyrum junceiforme and to a lesser extent *Ammophila arenaria. These species are native to the coast of western Europe, where they fulfil a key role in dune establishment. Being able to grow through sand accumulating among the culms, these grasses formed mounds where seeds or rhizome fragments were washed up during king tides. Where somewhat sheltered from the strongest impact of the westerlies, mounds gradually coalesced and formed short ridges at the landward side of the spit, and ‘dune fields’ towards its distal end. Circumstances favourable for dune field formation were enhanced by episodic processes in spit growth due to channel shifting in the tidal delta and the gradual lengthening of the main outlet channel. Austrofestuca littoralis and Spinifex sericeus joined the two foreign grasses in their pioneering role. The herbaceous Actites megalocarpa and the shrub Ozothamnus turbinatus established in the lee of the grasses, but conditions on mounds, dune crests and windward slopes are too severe for other species. Only at more sheltered sites is further development of vegetation possible. In the lee of the dune fields it has progressed into an open shrubland, initially of Ozothamnus turbinatus, Olearia axillaris and Olearia glutinosa, later enriched by Acacia longifolia var. sophorae, Leptospermum laevigatum and Leucopogon parviflorus. Wind-dispersed taxa form the dominant component of the vegetation, but several animal-dispersed species became established as well. The complement of woody species begins to resemble that of the dune scrub found elsewhere along this part of the Victorian coast, but severa