- A 0.6 ha area in North Wahroonga, Sydney NSW, where the plant and soil cover had been completely removed to expose the underlying sandstone rock surface, was examined in 1997, c. 70 years after the disturbance ceased. The area has remained relatively undisturbed since the 1920s, and the revegetation has been allowed to proceed unhindered. In total, 146 species were encountered in and around the area, 126 of them occurring in the quarried area. Twenty-six of these species are not native to the area, but they occurred almost exclusively in the south-east quarry working, which is adjacent to the closest residential area. The three quarry workings were clearly floristically distinct from each other, with the south-east quarry working differing from the other two in having many unique species (mainly the introduced species) and the east working being floristically de-pauperate. None of the measured soil physical or chemical variables was particularly correlated with the variation in floristic composition. There was a partial distinction between the plant species composition of the quarried area and the adjacent undisturbed area, with 17% of the native species encountered not occurring in the quarried area and a further 10% showing a significantly lower abundance in this area. However, the distinctive south-east quarry working was floristically no more different from the rest of the quarry than was the native area last burnt in 1990 from the native area last burnt in 1968, and the quadrats in the long-unburnt native area were rather similar in species composition to those of the north and east quarry workings. However, many of the species in long-unburnt vegetation will be represented in the community solely by a soil seedbank, and so this comparison of above-ground vegetation may be artificial. The soil structure and fertility both showed no consistent differences between the native area and the quarried area.
Deutsches Urheberrecht