Project title: Integrated conservation and translocation of the threatened banded ironstone species Tetratheca erubescens (Elaeocarpaceae).
Dates: 2017 - 2022
Funding: Cliffs Asia Pacific Iron Ore Pty Ltd
Location: Koolyanobbing Range, 60 km north of Southern Cross, Western Australia
- population ecology
- seed dormancy and enhancement
- propagation biology and translocation approaches
- pollination and seed dispersal
Tetratheca erubescens J.Bull has a WA state-level Declared Rare Flora – Threatened (DRF) status and was described in 2007. The species has an estimated population size of less than 6,500 individuals that are distributed over 3.5 ha. They are mostly small, multi-stemmed shrubs or herbs that occur largely on, or in close associations with banded ironstone formations (BIF) in the Koolyanobbing Range. Due to mining in the region, an integrated conservation and translocation project was established in 2017 to underpin the ecology, ecophysiology and translocation potential of this rare BIF endemic.
The main objective is to establish plants in new 'home-sites', as well as researching effective ways to propagate large numbers for in situ reintroduction programs. This will be achieved by understanding the ecophysiology, seed biology and ecology of T. erubescens across the range. Initial investigations have focussed on understanding ecophysiological responses of plants and the surrounding soil environment where T. erubescens populations are naturally found. This information will be compared to environments for potential translocation to determine site suitability, and quantify the success of translocation efforts through ongoing monitoring of plant functional attributes (e.g. growth and reproduction).
In addition, the research program will identify climate envelopes for seed germination and apply seed enhancements, such as priming or coating and/ or pelleting to improve recruitment from seed. To understand the reproductive ecology, key insect pollinators and seed dispersers of T. erubescens will be identified and therefore, determine the effectiveness of mating systems, reproduction and seedling recruitment in the landscape. The project aims to develop practical, effective and sustainable restoration of Tetratheca erubescens through understanding and optimising their establishment and environmental requirements – including functional interaction with substrates – and determining how these can be effectively utilised or recreated in restored systems to ensure long term persistence of species and viability of translocated populations.
We have recently established that T. erubescens:
- occur in highly restricted habitat and modelling showed few other areas on the range had a similar probability of being suitable habitat;
- aged seeds from the soil seedbank are quick to germinate;
- freshly collected seeds are dormant and show enhanced germination when nicked or exposed to smoke products; and
- T. erubescens plants occur in soil that has a different nutrient signature to areas with no Tetratheca plants.
The results from these investigations are now being used to develop and trial a translocation program that optimises the effective re-establishment of T. erubescens under field conditions.
Dr Carole Elliott (BGPA), Dr Wolfgang Lewandrowski (BGPA), Dr Jason Stevens (BGPA)
Dr Ben Miller (BGPA), Dr Siegy Krauss (BGPA), Dr David Merritt (BGPA), Dr Shane Turner (BGPA/UWA)