Abstract
Seed for restoring natural ecosystems is an expensive and finite resource. Yet seedling emergence is notoriously low in mining rehabilitation and restoration projects more generally. Unlocking this potential in broadcast seed has been critical to restoring a diverse kwongan ecosystem at Iluka’s Eneabba mineral sands mine, in the mid-west of Western Australia.
Using an innovative combination of rehabilitation practices in the sandy soils of Eneabba—seed burial, land imprinting, and an artificial soil crust—two-fold more seedlings emerged from broadcast seed in 2017 than from standard rehabilitation practice of ripping and seed broadcast. To combine and automate these practices in a single pass, we designed, built, and commissioned tractor-drawn equipment named ‘Flora Restorer’. Flora Restorer spreads fertiliser, scarifies the uneven soil, air-seeds a diverse size and shape seed mix, land imprints and thereby buries the seed, and sprays the soil surface with dilute bitumen emulsion forming an artificial soil crust to stop wind and water erosion.
Over the last four years of use, consistently two- to three-fold more seedlings have emerged from broadcast seed using Flora Restorer than from previous rehabilitation practice. Independently, long-term botanical monitoring has also demonstrated revegetation improvement using Flora Restorer, with species richness more than 50% higher and native plant cover more than double compared to rehabilitation at Eneabba over the previous 20 years. Flora Restorer demonstrates that large improvements in revegetation outcomes are possible in mining rehabilitation by automating seed sowing in combination with land imprinting and application of an artificial soil crust.