Pioneering direct seeding trials in Queensland show real promise for sand mine rehabilitation in SEQ
This new Queensland study published in Ecological Engineering is already transforming sand mine rehabilitation practices across South East Queensland. Led by Christopher Johnson (Griffith University PhD candidate and Senior Environmental Officer at Southern Pacific Sands) with some helpful guidance from Healthy Land & Water’s Portfolio Manager Mark Waud. The research showed that direct seeding can outperform traditional tubestock planting in both cost-effectiveness and ecological recovery when proper site conditions are met.
This innovative Queensland case study provides mining operators with a proven alternative that delivers superior environmental outcomes while significantly reducing rehabilitation costs, a win-win approach that could reshape restoration strategies across the region.
Read more about the encouraging results.
The direct seeding method was trialled across two rehabilitation sites at a sand mine nearby Bribie Island, with objectives, to evaluate its viability under the mine’s Progressive Rehabilitation and Closure Plan (PRCP).
The team applied a carefully selected mix of 15 seed varieties reflecting the sites’ local ecology, including 10 native woody species (e.g. koala food trees) and 5 native grasses. Then, over three years, monitored vegetation establishment, focusing on species richness, plant density, and competition with non-native species.
The native ecosystem site blew researchers’ expectations out of the water, exceeding PRCP plant density targets eightfold and yielded strong native diversity and densities.
The grazing site, however, faced greater challenges from pasture species, though still demonstrated moderate success.
Cost-effective, scalable, and ecologically robust
One of the most significant findings was the method’s cost efficiency, reducing rehabilitation costs by >30% compared to tubestock planting. When done right and the landscape cooperates, this revegetation method requires fewer man-hours and could be the answer for larger projects that require scalability.
Lead researcher Christopher Johnson emphasised that tailoring techniques to site conditions is critical, a sentiment that restoration expert Mark Waud supported, noting, “Making direct seeding work means getting the recipe right.”.
The mentorship behind the method
Mark and Chris first met as fellow bush regenerators a few lifetimes ago, sparking years of collaboration and knowledge-sharing. In 2020, Mark was invited to visit the sand mine to explore possibilities and brought valuable insights from his Western Australian experience to help refine the early direct seeding trials.
“That 2020 visit is really where the idea for this project took shape”, said Chris. “Mark will probably downplay his role and say he was just ‘kicking dirt’, but his industry perspective, as well as the papers and guides he shared in follow-up chats and emails over the years, added a lot of value.”.
A model for the future
While more Queensland-based research is necessary to evaluate its application across different bioregions, this research confirms that direct seeding has legs. When paired with tailored site preparation and proper weed management, this rehabilitation strategy is cheaper and meets or exceeds ecological recovery targets. For those designing restoration projects, direct seeding could prove to be a great tool for more efficient and scalable land recovery efforts across Queensland.
At Healthy Land & Water, we’re proud to support such pioneering research, and to support experts like Mark Waud, whose industry-wide mentorship continues to shape best practices in environmental restoration.
This study was made possible through collaborative efforts between Southern Pacific Sands, Healthy Land & Water, and Griffith University’s Green Research Infrastructure Labs (GIRLS).
Want to learn more? Read more about the findings in this Griffith University article.
