Australia’s commitment to preserving its native plant biodiversity is shown by its domestic policy goals and by the international agreements Australia has entered into. While the protection and enhancement of the habitat of native species (sometimes called in situ conservation) is obviously a priority, it is also recognised that ex situ conservation may be necessary to prevent the extinction of some species. For plants, ex situ conservation could mean being grown in a botanic garden or having seed or genetic material in storage.
According to Australia’s Biodiversity Conservation Strategy 2010-2030, it is the responsibility of governments, the science sector, Indigenous peoples, and private landholders to maintain and enhance in situ and ex situ conservation measures to conserve species and genetic diversity. Australia’s international targets with regard to ex situ plant conservation (as set out in the Global Strategy for Plant Conservation (GSPC) under the Convention on Biological Diversity – CBD – of which Australia is a signatory) are more specific: “at least 75% of threatened plant species in ex situ collections, preferably in the country of origin, and at least 20% available for recovery and restoration programmes.”
In order to assess Australia’s progress towards meeting these policy goals, it is important to determine which species, especially threatened species, are in ex situ conservation and how well those ex situ collections are preserving the genetic diversity of the species into the future. Maintaining genetic diversity is essential as it allows a species to respond to changing conditions and other threats. It is not enough simply to have an example of a threatened species in a botanic garden. For such ex situ collections to be useful for conservation, they need to be representative of the genetic diversity of the wild populations of the species.
For my Summer Scholar project, I was placed in the Biodiversity Science Branch of Parks Australia, part of the Department for the Environment, and based at the Australian National Botanic Gardens (ANBG) in Canberra. The aim of my project was to assess the representativeness of the collection of threatened plant species held at the ANBG to allow informed decisions to be made about the future direction of this collection. Much of my time was therefore spent analysing the records relating to the plant species in the ANBG’s Living Collection that are listed under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The rest of my time was spent talking to the people at the ANBG to find out how it works and how decisions are made about threatened species.
The first part of my work was a general analysis of all the EPBC-listed species. While genetic diversity of each threatened species could, in theory, be assessed directly, this would take considerable time and resources. Therefore, it was necessary to use a proxy for genetic diversity to assess the representativeness of the ANBG collections. For this project, the wild provenance of the ANBG Living Collection was compared to the geographic distribution of the species. Given the number of species, the first analysis just looked at the number of genotypes of each EPBC-listed species that were held in the ANBG
Living Collection and how many of the original wild locations of those genotypes are known.
The second part of the project was to develop a methodology to target future collecting of specific threatened species in order to increase representativeness. This involved looking at each species and mapping its known geographic distribution against the provenance of the ANBG Living Collection plants to identify where the gaps are.
To assess ex situ plant conservation on a national scale, it would be necessary for all the botanic gardens and seed banks to do a similar assessment. While useful to the ANBG itself, this project was also intended to produce a methodology to show other botanic gardens how such an assessment could be done. The third part of my project was to examine the usefulness of the idea of coordinating the efforts of all Australia’s botanic gardens in a National Living Collection and how that might work in relation to threatened species.
“The ANBG Living Collection is holding about 24% of the EPBC-listed plant species, almost a third of the aspirational target of 75% of threatened species in the Global Strategy.”
There are currently 1255 plant species listed as being Critically Endangered, Endangered or Vulnerable under the EPBC Act. 298 of these species are held in the ANBG Living Collection. This means that the ANBG Living Collection is holding about 24% of the EPBC-listed plant species, almost a third of the aspirational target of 75% of threatened species in the GSPC. The second part of this target is that 20% of those species are ready for recovery or restoration. For this to be feasible, a reasonable representation of the species’ genetic diversity would be necessary, and yet 54% of the EPBC-listed species in the ANBG Living Collection are represented by only one genotype (indeed, only 20% of the analysed species are represented by more than three genotypes).
There is considerable enthusiasm and expertise at the ANBG about the conservation and cultivation of threatened natives. However, the ANBG has limited resources and conservation is but one of its aims. It is also a space for learning and enjoyment and serves the public in many ways.
In addition to this, growing plants in the garden is just one method of ex situ conservation. Many threatened species are conserved in the Australian National Seed Bank and in other seed banks around Australia. It is possible to more easily store a great range of genetic diversity in seed. However, representativeness in the Living Collection is still important as there are species whose seeds do not respond well to seed banking or who do not produce viable seed. And growing plants in the garden also provides important information for restoration efforts about how best to cultivate the plant.
It is never going to be possible for one seed bank or one botanic garden to conserve all of Australia’s threatened plants. At the moment, ex situ conservation of the threatened species in botanic gardens around Australia is left to the collections policy of the individual botanic gardens. Given the resources and expertise required to conserve these species, it would be sensible to have some sort of National Living Collection, if only so that everyone knows who is already conserving what species. This would allow botanic gardens to share expertise on the conservation of particular species and potentially, to make decisions about which species it would be worth devoting their energy to. Is it the right approach to focus on individual species as opposed to conserving ecosystems? Should the preservation of the genetic diversity of common but important species be prioritised over rare and threatened species? These are areas where science can inform policy choices.
At the ANBG there are three areas where science is informing policy. The ANBG’s information management systems allow policy makers to know what is in the ANBG’s collections and make decisions about future strategies based on this. The horticultural and germination expertise of the ANBG’s staff inform policy makers about what is possible when it comes to conserving particular species and what sort of resources are needed. Science can also inform policy when it comes to making decisions about which species the ANBG should use its limited resources to conserve. My project fits into the information management area; its findings will be used to inform the development of the ANBG’s Conservation Policy.
I thoroughly enjoyed my time at the ANBG and at the Fenner School at the ANU. I would like to acknowledge all the people in both places who were so generous with their time and expertise, as well as the NERP team who facilitated the project.