TEMPORAL TRENDS IN PLANT-SPECIES COMPOSITION ON MINED SAND DUNES IN MYALL-LAKES-NATIONAL-PARK, AUSTRALIA

The floristic composition of the vegetation of mined and unmined sand dunes at Bridge Hill, in Myall Lakes National Park, was studied from 1982-90 inclusive. Data from mined sites ranging in age from 2-15 years post mining, with replication of time since mining in both time and space, were incorporated in the study. The mined part of the Bridge Hill dune is very different in plant species composition compared with either the dune prior to mining or to the adjacent unmined duties. The mined dune also displays a temporal development of species composition over the period 2-15 years post mining, the dominant trend being a reduction in similarity to that of the dune prior to mining. Mining resulted in significant increases in the abundance of six introduced species, and in significant differences in the abundance of 49% of the native species. Species richness and diversity increased during the period 2-15 years post mining, and a significant component of this could be attributed to the presence of the introduced species.