Bang for your buck: revegetating arid sites using coloniser species

Authors: Horner, B; Christie, G; Williams, B; Scanlon, AT; Lemon, J Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_rep/1915_60_Horner

Cite As:
Horner, B, Christie, G, Williams, B, Scanlon, AT & Lemon, J 2019, 'Bang for your buck: revegetating arid sites using coloniser species', in AB Fourie & M Tibbett (eds), Mine Closure 2019: Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 753-758, https://doi.org/10.36487/ACG_rep/1915_60_Horner



Abstract:
Revegetation of mine sites in the arid zone is inherently challenging because of the harsh environmental conditions, low and irregular rainfall, high temperatures and winds and complex soil conditions. Issues with erosion and dust contribute to these challenges. A ‘ground up’ approach to revegetation was used in the recovery of a large ash storage area of arid South Australia. This approach works with the natural process of succession to build habitat; it involves sowing high densities of native colonising species. A total of 2,700 kg (15 kg per ha) of native seed was spread over 180 ha of the capped site from June 2017 to August 2017. Despite lower than average rainfall (160.3 mm in 12 months), the mean density of native plants in August 2018 was 1.8 ± 0.6 plants per m2 (n = 50 quadrats), which represents 3.2 million individual plants across 180 ha. The standing crop of seeds for three Atriplex species (A. holocarpa, A. lindleyi and A. vesicaria) was assessed from photographs of all individuals within 10 plots, 10 × 10 m in size. Based on plant volumes and densities and scaling up for the 180 ha area, those species produced more than 500 kg of seed in August 2018; equivalent to almost a fifth of the original quantity of seed added to site. The value of this seed exceeded $76,000, and the number of individual seeds calculated for that point in time was 42.6 million. Importantly, these figures represent the standing crop for three species in August only; many colonising species produce multiple crops per annum and will increase the number of seeds (and plants) produced onsite in perpetuity. As prolific seed producers, colonising plants bolster soil seedbanks for self-sustained recovery with few other interventions or costs, providing plenty of ‘bang for your buck’.

Keywords: colonising species, dust mitigation, native seed, natural systems, revegetation

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