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From the early 1940s until 1993, the 600 hectare West Coast Fossil Park (WCFP) was mined for phosphate.
In 1996, plots were established to determine the most cost-effective approach to restore the exposed
phosphate beds, as well as sites in the tailings dam area. Three replicates of control and treated plots were
established. Treatments at the phosphate beds site included fertilizer addition, brushpacking and topsoiling.
Seed was added to all treatments on the phosphate beds. In tailings dam plots, the treatments included
adding seeds, or planting seedlings of different grass and early-succession species with and without
brushpacking. We resurveyed the plots between March and April 2008. Our objectives were to record
species richness and the percentage cover of species and growth forms within treated plots, and to compare
them to the control plots and to plots from an undisturbed reference site. Species richness was determined by
counting all the species in a plot. Species cover was determined using a point intercept method. We also
measured the cover of litter and bare ground using this approach. Comparisons between plots were visually
assessed, using a DCA ordination analysis. Species richness, plant, litter and bare ground cover, as well as
plant cover of the major growth forms were compared with ANOVA and Student-Newman-Keuls tests for the
phosphate bed and tailings dam sites separately. Results show that all control and treated plots had
significantly fewer species and lower cover than the reference plots. Tree and succulent plant cover was also
generally higher in the reference plots. The absence of restios in the control and treated plots was a
significant difference between previously-mined and reference sites. There were few significant differences
between treated and control plots at the tailings dam site for all variables. The main difference between
treated and control plots at the phosphate beds was the increase in short-lived shrubs at sites which received
topsoil prior to seeding. The dramatic differences between previously-mined sites and reference sites are
primarily attributed to the comprehensive transformation of the substrate available for plant growth on
previously-mined sites. Three reasons for the lack of difference between treated and control plots are
suggested. First, after twelve years, the initial impact of the treatments might be obscured. Second,
significant substrate differences between plots and low replication might make it difficult to find statistically
meaningful differences. Third, greater intervention effort in terms of labor and seed or seedling quantity
might have produced a different result. We conclude by acknowledging the significant role that the
rehabilitation project has played in the region.
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