Using fire, planting, and topsoil translocation for restoration in South African fynbos: assessing the success and cost-effectiveness of various restoration treatments

Abstract

The successful restoration of endangered habitat types at a low cost is of vital importance. We tested how successful and cost-effective six combinations of restoration treatments were in the Cape Floristic Region of South Africa. Treatments were applied to an area that was primarily covered invasive alien grasses. Treatments that tested combinations of burning, direct sowing of seed, and planting of seedlings, aimed to test the synergistic effect of three treatment factors. Topsoil translocation aimed to determine if this, combined with planting, can restore native shrub cover and whether the addition of mulch and seed can improve overall success. The mechanical removal of invasive grasses, sowing and planting, were tested in the absence of fire. Both topsoil translocation treatments and the treatment that had been burned, sown and planted (“Burn-sow-plant”) led to plant species richness resembling near-pristine plots and approximately 30% higher than the burn-only treatment (“Burn”). Native shrub cover was the highest for treatments which included planting. Survival for planted species was 36–41% higher for Burn-sow-plant. The contribution of sowing was low, with 9–16% of species sowed being present across treatments. We show that topsoil translocation can be successful if combined with planting. Burn-sow-plant was most successful at a reasonable cost, despite planting being expensive, whereas Burn and Burn-sow were less successful, but cheaper. The treatment in which grass was removed before sowing and planting was the least successful and most expensive. We conclude that the most successful treatments are not necessarily the most expensive.