Vegetation Succession After Bauxite Mining in Western Australia Melanie A. Norman, 1,2 John M. Koch, 1 Carl D. Grant, 1 Tim K. Morald, 1 and Samuel C. Ward 1 Abstract Alcoa World Alumina Australia has been rehabilitating bauxite mines in the jarrah forest of Western Australia for more than 35 years. An experiment was established in 1988 using three different seed treatments (legume and small understorey mix, small understorey mix only, and no seed) and two fertilizer treatments (N and P, and P only). The objectives of this study were to (1) document vegeta- tion changes in the first 14 years after bauxite mining; (2) assess whether the vegetation is becoming more similar to the unmined forest; and (3) gain a better understanding of successional processes. Seed treatments significantly affected 13 of the 14 measured vegetation characteristics. Native species richness was higher in seeded than in un- seeded sites at 1, 2, and 5 years of age, whereas diversity and evenness were generally higher at all assessment ages. Exotic species density was higher in unseeded than in seeded sites from 5 years onward, whereas richness was higher from 8 years onward. Nitrogen fertilizer signifi- cantly increased exotic species richness, density, and cover. Ephemerals dominated plant density in all rehabilitation treatments over time, whereas seeder species dominated cover. In contrast, resprouting species dominated density and cover in the unmined forest. Orchids were the only species that were not present in the first year in rehabili- tated sites but increased in abundance over time. Vegeta- tion composition in rehabilitated areas did not become more similar to the unmined forest during the 14 years since seeding, instead strongly reflected the initial species mix. Rehabilitated bauxite mines appear to follow the ini- tial floristic composition model of succession. Key words: fertilizer, jarrah forest, rehabilitation, seeding, species richness, understorey. Introduction Alcoa World Alumina Australia (Alcoa) has carried out bauxite mining in Western Australia’s Jarrah (Eucalyptus marginata) forest since 1963. The current objective of the rehabilitation is to establish a self-sustaining jarrah forest ecosystem, planned to enhance or maintain water, timber, recreation, and conservation values. Approximately 550 ha of forest are cleared, mined, and rehabilitated each year at Huntly and Willowdale mines, whereas Del Park and Jarrahdale mines are now closed. Sites rehabilitated after 1976 were seeded with an understorey composed mainly of native legume species (e.g., Acacia pulchella, A. urophylla). In the early 1980s, rehabilitated sites were planted with a mix of local and eastern Australian euca- lypt species. Eastern Australian eucalypts were used due to the unknown impact, at that time, of Phytophthora cin- namomi (jarrah dieback disease) on the native overstorey. Since 1988, a native overstorey has been established in rehabilitated sites by seeding or planting jarrah and Marri (Corymbia calophylla). A more detailed account of the mining and rehabilitation process is given elsewhere (Ward et al. 1993, 1996; Gardner 2001). The investigation of successional patterns in rehabili- tated mine sites is a subject of both practical and ecologi- cal importance and can be used to indicate whether the vegetation is on a development trajectory toward a desired endpoint. Numerous successional theories have been pro- posed for a range of ecosystems (e.g., Clements 1916; Egler 1954; Noble & Slatyer 1981; Westoby et al. 1989; Hobbs & Harris 2001). The classical view of ecological succession is that, following a disturbance, several assemb- lages of species progressively occupy a site, each giving way to its successor until a community that is able to reproduce itself indefinitely finally develops (Clements 1916). Egler (1954) termed this classical view of succession ‘‘relay floristics’’. However, he concluded that in many situations, it is the ‘‘initial floristic composition’’ (IFC) fol- lowing disturbance that determines future shifts in domi- nance. In this type of community succession, the overall pattern of development of the stand will be influenced by the species composition that first establishes, and subse- quent developments are merely changes in the relative abundance of species (Hobbs & Legg 1983). Numerous studies have been conducted in post-mining rehabilitated vegetation (coastal dunes, temperate hard- wood forests, and tropical forests) to determine if the 1 Alcoa World Alumina Australia, Applecross, WA 6953, Australia. 2 Address correspondence to M. A. Norman, email melanie.norman@alcoa. com.au Ó 2006 Society for Ecological Restoration International 278 Restoration Ecology Vol. 14, No. 2, pp. 278–288 JUNE 2006