sand dune

The sand dune system at Chrystalls Beach, New Zealand comprises front dune, dune hollow and rear dune areas. On the front dunes are two communities: one on the seaward face of the dunes, and another on the landward face. Most of the dune hollow is occupied by a series of grassland communities, but there are areas of a distinctive cushion community, still largely native in its species composition. It is suggested that the cushion community is maintained against invasion by a switch, possibly involving sand grain size, soil organic content, water supply, wind and magnesium:calcium ratio.

A range of slack vegetation in southern New Zealand was described by detailed sampling of four dune slacks, contrasting in topographic situation and in vegetation. Comparison is made with a slack previously sampled on Stewart Island. The five slacks differed markedly in the plant communities present. One slack, where there was considerable peat accumulation, was dominated by the megaherb Phormium tenax and the restiad Leptocarpus similis.