If you access the documents via the EPA link (
https://www.epa.wa.gov.au/proposals/arrowsmith-north-silica-sand-project then go to 3. -> Assessment -> Environmental Review ) you can open all the appendices.
I have always been curious about the VDT, so was pleased to be able to see the Mattiske report on the Iluka study.
It's interesting reading (or insomnia therapy) and actually doesn't pull any punches in suggesting, if I read it correctly, that there are pros and cons to the technique, but also that the varying environmental conditions over the 4 years of study may be just as much a cause of the inconsistent results.
(there are 4 trial areas, or "treatments")
Total species richness excluding introduced species decreased within all four treatments since the 2015 monitoring. This is most likely due to a reduction in annual species seen in 2019 compared to 2015. Total species richness including introduced species also decreased within all four treatments for the same reasons. ***
Between 2012 and 2014 within all four treatments there was a noticeable increase in the proportions of alive seeder species and a reduction in the proportions of alive resprouter species. However, the 2015 and 2019 surveys have seen an increasing trend within all four treatments, in the proportions of alive resprouter species, with a concurrent reduction in the proportions of alive seeder species.***Mean alive native foliage cover has markedly increased within all four treatments. All of the treatments seeing an increase of over double the mean alive native foliage cover recorded during the 2019 monitoring.
***
Some of the dominant shrubs and trees have large lignotubers and/or lateral roots and deeper roots. The latter larger lignotubers and roots pose some difficulties in designing mining and rehabilitation methods for the proposed silica sand operations. The latter larger root or underground organs include species of Banksia, Xylomelum, Eucalyptus and Macrozamia. Of the latter the absence of some of these species in the VDT trials reflects the difficult of establishing these species from propagules.There were lower numbers of larger trees and shrubs in North Arrowsmith than in Central Arrowsmith. Nevertheless challenges still persist on a range of larger shrubs that have root systems that will need addressing in the planning phase of the mining and rehabilitation phases of the operations.I guess that last sentence is hinting that VDT is not a silver bullet, and with A/Central and indeed Muchea, VRX may need to provide more robust planning around preservation and rehabilitation of larger vegetation.
(20min delay)
