Ecophysiology as a tool to develop novel post-minesite restoration techniques in a Mediterranean ecosystem

Background/Question/Methods: The extreme summer drought in southwest Western Australia coupled with the increased mechanical impedance of re-deposited soils following mining operations create a barrier to seedling establishment during rehabilitation. Controlled environment glasshouse experiments were conducted to evaluate the physiological adaptations of three framework woodland trees (Banksia attenuata, B. menziesii and Eucalyptus todtiana) in response to water stress and soil compaction. Plant adaptations to these individual stresses included increased water use efficiency and altered root morphology. However, seedlings grown in an environment containing simultaneous drought and high soil compaction were unable to survive despite these adaptations. Techniques to alleviate the negative effects of soil compaction were subsequently investigated by either ameliorating soil - adding organic (native woodland mulch) and inorganic (crushed rock) amendments into the soil profile or empowering the plant – or chemically priming the plant with the chemical DIHB (3,5-diiodo-4-hydroxybenzoic acid), previously shown to increase root growth through compacted soils by limiting ethylene production and absorption by the roots. Results/Conclusions: The soil amelioration treatments did not increase root growth in any plant species despite increasing porosity (root channels) of the compacted soil profile, though a combination of the different amelioration techniques presented here has the potential to significantly increase restoration success within Mediterranean environments containing compacted soils.