Restoring Jarrah Forest after Bauxite Mining in Western Australia — The Effect of Fertilizer on Floristic Diversity and Composition

Abstract

South-western Australia is well known for its diverse and mostly endemic flora that live on some of the most P-impoverished soils in the world. One of the challenges in the restoration of these ecosystems after mining is to establish colonizing species to facilitate vegetation succession, and to establish the dominant tree species, both without compromising the diversity and composition of the climax community. P-fertilizer is used to replace the nutrients that are lost as a result of the mining process, and to achieve these primary goals. In this paper, we explored the effects of P-fertilizer on the diversity of the jarrah forest that is restored after bauxite mining. We assessed the restored jarrah forest 13 years after its establishment and compared it to nearby unmined jarrah forest. The residual effects of the P-fertilizer, applied prior to seeding, were evident in the furrows of the rip-lines in the fertilized plots. We found that the native species richness, diversity and evenness of the restored jarrah forest were reduced with the application of P-fertilizer compared with the values of these measures for unmined jarrah forest. These measures were similar for the unmined jarrah forest and for the restored sites where no P-fertilizer was applied. Within the restored sites, the application of P-fertilizer had no statistically significant effect on native species richness, diversity and evenness. The similarity of the restored jarrah forest to the unmined jarrah forest decreased with increasing P (i.e. 0, 80 and 120 kg/ha P). The composition of the restored jarrah forest was different to that of the unmined jarrah forest but this was unrelated to the application of P-fertilizer.