The Inclusion of High Interest Native Plants in Mine Site Restoration Programs: Propagation, Translocation and Field Re-introduction

The comprehensive research conducted throughout both stages of this project culminated in the first translocation trial on a mining lease for two Endangered Persoonia species. Both Persoonia hindii and Persoonia hirsuta are a critical component to post-mining rehabilitation targets. Translocation is the deliberate, human-mediated movement of plants from one location to another. Until recently, translocation using tubestock of Persoonia spp. was not possible due to significant challenges to propagate either species. Through careful examination of the literature, experiments were designed and conducted that resulted in optimised techniques enabling us to produce a “population” of plants suitable for translocation. Healthy plants were translocated in May 2019. The success of this stage of the project coupled with the key results from stage one of this project, highlight the importance of long-term research to establish meaningful on-ground outcomes for the restoration industry.

Several propagation methods were investigated and optimised for P. hirsuta. Previously, seed collection from wild plants was not possible due to poor fruit set. Furthermore, propagation from vegetative cuttings taken from plants was unsuccessful, creating significant barriers to producing sufficient plants for translocation. The discovery of additional, vigorous populations provided an opportunity to collect a significant number of fruits as well as cuttings from multiple populations. The effect of the endocarp on germination success following short-term storage and heat treatments was examined using novel but optimised techniques. These results highlighted the importance of the endocarp in preserving seed viability during storage. Coupled with this germination experiment, was an optimisation experiment examining the effects of plant growth regulator chemical treatments on vegetative cuttings. An upper threshold of indole butyric acid (IBA) concentration had a negative effect on cutting strike rate, which was identified using plant material from three populations. An additional outcome from this experiment was the possibility of a negative relationship between the age of the parent plant and strike rate.

A predictive environmental model was used as a novel way to explore the suitability of P. hindii habitat and relate this information to identifying potentially suitable translocation sites. The environmental model indicated that elevation was the strongest predictor for suitable habitat, followed by aspect. Data from soil collections was incorporated into the environmental model, and the output provided key information on the factors that might be conducive for P. hindii survival. These results were then used to help guide suitability criteria for selection translocation sites.