Spinifex-mallee revegetation: Implications for restoration after mineral-sands mining in the Murray-Darling Basin

Mineral-sands mining in the semiarid and arid zone of south-eastern Australia is now a widespread disturbance that may adversely affect large areas of remnant vegetation, including mallee (Eucalyptus spp.) with hummock grass or spinifex (Triodia scariosa) understorey. No broad-scale restoration projects have been undertaken to revegetate mallee Eucalyptus species with spinifex. We report on the survivorship and relative importance (spatial coverage) of hand-planted tubestock 10 years after establishment in 2001, which included mallee Eucalyptus, Triodia scariosa, Acacia spp. and Hakea spp. These taxa are the dominant plants in a semiarid dune-swale system on a former mineral-sands mine licence area in semiarid, north-western Victoria. Mean survivorship of tubestock was 0.58±0.04. Spinifex (Triodia scariosa), needlewood (Hakea) and several mallee species (Eucalyptus spp.) survived substantially better than the average of all tubestock-planted species, although Acacia spp. had low survivorships. Although the plantings were undertaken in the early stages of the most severe drought in the instrumental record (the 'Millennium drought'), several taxa survived well and species such as spinifex established and developed ground coverage greater than the benchmark values for the ecological vegetation class of the location. We conclude that hand-planting of tubestock can achieve restoration objectives for this component of spinifex-mallee vegetation, even under extremely arduous conditions associated with long-term drought. We also herald the importance of taking a long-term view to the assessment of revegetation success, in this case 10 years.