Carole Elliott, Shane Turner, Eric Bunn, Kings Park Science, Biodiversity and Conservation Science; Botanic Gardens and Parks Authority; School of Biological Science, University of Western Australia

Conserving a diverse range of plant species is challenging—simply put there is no one solution for all. Diversity of habitat, geography, seed biology, ecology, abiotic or biotic interactions and responsiveness to a range of threats means that a broad toolbox of options is needed for effective conservation management of Western Australia’s threatened flora.

At Kings Park Science, a science program with the Department of Biodiversity, Conservation and Attractions, the Conservation Biotechnology research team undertake research into ex situ conservation of the most difficult to propagate, or highly threatened, species. They maintain 40 species in their cryopreservation facilities and a further 50 species are maintained in tissue culture under controlled conditions. In comparison, the Kings Park Species Recovery group are mainly involved with in situ conservation programs that range from modelling potential localities for new translocated populations to establishing benchmarks for measuring translocation success and long-term sustainability. Many threatened species have ended up in this predicament through habitat loss due to two main activities—clearing for agriculture and, more recently, mining.

Since British settlement in 1829 over 90% of the Western Australian wheatbelt region has been cleared for agriculture. Symonanthus bancroftii was thought to be extinct as it had not been sighted since the 1940’s. In 1997 a single (male) plant was found in an area previously used for road aggregate storage near the town of Ardath (WA), followed by a female plant in 1998 (after an intensive search). These two plants were successfully established in tissue culture (Panaia et al., 2000). As part of this program, in 2001 a third (female) plant was produced from in vitro germinated seed (harvested from an ex situ container collection of micropropagated plants grown in Kings Park). These three genotypes were mass produced through micropropagation and made available for translocation. After several translocation attempts, eighty plants were successfully established across two sites with mature female plants producing many viable seeds; in fact more than 10,000 seeds were harvested over several years and seed banked. The take home message is to establish ex situ security of as many plants as possible as a first priority, then attempt translocation when convenient to do so.

The critically endangered Western Australian species Symonanthus bancroftii, in which a single male plant was rediscov-ered in 1997, followed by the discovery of a single female plant in 1998. A) shows Ex situ micropropagation of S. bancroft-ii growing in tissue culture; B) In situ translocation of S. bancroftii micropropagation derived greenstock. Credit: Eric

In contrast to the experience with WA wheatbelt flora, mining activities are more likely to affect narrow range endemics restricted to economically valuable mineral deposits. Species impacted by mining activities often have several thousand healthy plants, albeit within a small, highly localised range. In contrast, most threatened species in agricultural areas possess few individuals that are often scattered, so the focus with these is more on rescuing and conserving what remains. In many cases species impacted by future mining are intensively studied prior to being impacted, which is a common requirement for receiving permission to proceed with mining. For mine impacted species the initial emphasis is on understanding their ecology prior to disturbance, followed by development of restoration tools to allow successful repatriation of plants into suitable habitat to offset losses due to mine associated activities.

The threatened Western Australian species Ricinocarpos brevis, found in areas severely impacted by iron ore mining. A) In situ translocation of R. brevis seedling greenstock after installation on a mining waste rock landform; B) Seventeen month old seedling greenstock plant of R. brevis. Credit: Carole Elliott.

For example, Ricinocarpos brevis is restricted to banded ironstone ranges that have had conservation research programs funded by mining companies, as this species has been considerably impacted by iron ore mining. Research into population genetics, reproductive ecology, seed  biology and propagation biology have helped inform in situ translocation programs and formulated effective conservation management actions. These insights have seen the successful establishment of a large and healthy translocated population on a waste rock landform adjacent to natural populations, to directly offset losses due to mining, which in recent years have begun to flower and fruit (Turner et al., 2017). Plants were established through a variety of means including direct seeding, cutting derived greenstock and seed derived greenstock using a number of different in situ treatments and planting approaches.

Investment in threatened plant species research provides critical information for the creation and maintenance of ex situ germplasm collections and in situ translocations that are integral for species that are on the verge of extinction. While for other threatened species not directly impacted by immediate habitat loss, research is better targeted towards the development of experimental frameworks that identify and refine the best approaches for future translocations through a thorough understanding of the ecology of the species in question and how it is regulated by its environment.

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