Optimising seed broadcasting and greenstock planting for restoration in the Australian arid zone

Abstract

Vegetation within some parts of Western Australia has been degraded by resource extraction, and ecological restoration is necessary to prevent erosion and reinstate plant biodiversity. Two restoration approaches, seed broadcasting and planting of seedlings, were tested with plant species (Acacia tetragonophylla F. Muell., Atriplex bunburyana F. Muell. and Solanum orbiculatum Poir.) known to have been dominant prior to mining activities in the World Heritage Area at Shark Bay. For broadcast seeding, soil raking and/or ripping increased seedling emergence, but only after sufficient rainfall. Survival of A. bunburyana seedlings (≤92%) was higher than A. tetragonophylla (≤13%) almost two years after planting and soil ripping partly alleviated soil impedance and resulted in increased seedling survival. Shoot pruning, fertiliser and moisture retaining gel had a reduced or detrimental effect on survival. Seedling survival differed between the three experimental sites, with electrical conductivity being the most noted soil difference between the sites. Restoration in the arid environs of the World Heritage Area at Shark Bay in Western Australia is challenging, but this study shows that seedling establishment is technically feasible and provides methodology useful to other arid restoration projects.