13 minute read
Professional Networks: Reflections on Congress' Germplasm Conservation Symposium
Reflections on the 7th Global Botanic Gardens Congress Germplasm Conservation Symposium – Germplasm Conservation in Australia – a network of expertise for a biodiverse flora
Germplasm Symposium presenters (left-right: Amelia Martyn-Yensen, David Merritt, Jenny Guerin, James Wood, Tom North, Damian Wrigley, Karen Sommerville)
Advertisement
Damian Wrigley, Australian Seed Bank Partnership, The Council of Heads of Australian Botanic Gardens; David Merritt, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions; The University of Western Australia; Karen Sommerville, The Australian PlantBank, Australian Institute of Botanical Science, Australian Botanic Garden, Mount Annan; James Wood, Tasmanian Seed Conservation Centre, Royal Tasmanian Botanical Gardens; Jenny Guerin, South Australian Seed Conservation Centre, Botanic Gardens and State Herbarium; Tom North, National Seed Bank, Australian National Botanic Gardens, Amelia J. Martyn Yenson, Australian Network for Plant Conservation; The Australian PlantBank, Australian Institute of Botanical Science, Australian Botanic Garden, Mount Annan.
Australia is globally recognised as being one of 17 mega-diverse countries, boasting a substantial number of endemic flora and fauna. Australia’s known flowering plants exceed 23,000 species and, as identified by Dr Rachel Gallagher at the 13th Australasian Plant Conservation Conference (2022), ‘with great flora comes great responsibility’ (Gallagher, 2022); a sentiment not lost on Australia’s botanic gardens and seed banking community.
The recent State of the Environment Report 2021 (Murphy & van Leeuwen, 2021) highlights the threats and impacts affecting the health and resilience of the Australian landscape, underscoring the challenges we face in maintaining healthy, functioning ecosystems for the future. The report’s authors were damning in their assessment of the nation’s efforts to ameliorate threats and sustainably manage the Australian environment. It is clear that better and more targeted efforts and investments are required to underpin successful conservation management interventions from researchers, practitioners and other experts across a range of disciplines if we are to reverse the current trends of degradation and decline.
By the time this article is published, the global community will be negotiating the Post-2020 Biodiversity Framework under the Convention on Biological Diversity at the 15th Conference of the Parties in Montreal, Canada. This important global meeting will include a concerted effort by
the Global Partnership for Plant Conservation to secure support from governments for an updated Global Strategy for Plant Conservation, a key international strategy that helps secure support for plant conservation in Australia.
There has never been a better time to highlight the expertise and opportunities available to achieve these ambitious global goals through botanic gardens and seed banks as demonstrated at the recent 7th Global Botanic Gardens Congress.
The Germplasm Conservation Symposium, held on day three of the Congress, brought together conservation experts from across the Australian Seed Bank Partnership (ASBP). Co-hosted with the Australian Network for Plant Conservation (ANPC) and sponsored by the Council of Heads of Australian Botanic Gardens (CHABG), the symposium demonstrated the contribution seed banks make to local, national and global efforts to conserve native plants.
The symposium covered aspects of orthodox and non-orthodox seed banking, including exceptional species, special collections, and collaborative efforts to conserve Australian orchids. The symposium wrapped up with a summary of how the implementation of Australia’s national program of seed conservation and research contributed to production of the 3rd Edition of Plant Germplasm Conservation in Australia, a highly regarded manual for ex situ conservation.
In this article we summarise the proceedings of the Germplasm Conservation Symposium, and provide information on where to access the full suite of resources related to the 3rd Edition of Plant Germplasm Conservation in Australia.
Orthodox seeds
Dr David Merritt kicked off the symposium speaking on methods for predicting the lifespan of orthodox seeds in storage. David’s talk discussed how seed banking is a primary strategy for the conservation of plant species and their genetic diversity. The vast numbers of seed banks, which have been securing seed collections globally over many many decades, are a valuable resource for preventing the extinction of wild plant species. Collecting programs in seed banks also provide propagules for a range of conservation activities, including threatened species translocations, ecological restoration, research, and public education and display in botanic gardens. David illustrated how we are all grappling with the increase in size, diversity and age of seed collections and how this presents challenges for long-term maintenance and management. With the primary goal of seed banking being to maintain the quality and viability of the stored seeds until they are required for use – potentially years or decades into the future – it is fundamental that we collectively continue to improve our understanding of the longevity of these diverse collections to guide storage procedures and viability monitoring schedules. However, one of the challenges highlighted in the talk is that we still do not possess the means to predict, at the time of banking, how long individual collections of seeds will survive. David delved into studies of the longevity of orthodox seeds of Australian species, including findings from the modelling of seed ageing data for hundreds of diverse species examining seed, plant, and environmental traits associated with seed longevity, and the identification of species that produce desiccation-tolerant, but short-lived, seeds. David gave a presentation on his collaborative research, targeting viability testing of older seed collections to further test the hypotheses regarding species that may produce short-lived seeds, and the application of respirometry to predict the early onset of seed viability decline in storage.
David Merritt
Rainforest species
Dr Karen Sommerville provided an insight into new tools to aid the conservation of rainforest seeds. These tools are critical as seed banking is an efficient method for conserving plant species ex situ but the banking of rainforest seeds has been hindered by lack of knowledge as to which species are tolerant of the necessary drying and freezing.
As part of the Rainforest Seed Conservation Project, Karen and her colleagues assessed 156 Australian rainforest species for seed banking suitability by comparing the germination of fresh seeds to that of seeds dried at 15% RH and stored at −20 °C. They found 64% of species were
tolerant of the drying required for standard seed banking and a further 10% were at least partially tolerant. Easily measured characteristics such as seed moisture content and dry weight were found to be useful in predicting the response to drying, leading to the development of a simple decision key that may be utilised to quickly assess the response of previously untested species.
Of 107 species tested for response to freezing after drying, 24% were found to be short-lived in storage at Karen Sommerville −20 °C. Thermal analysis showed that most species had seed components that were not stably frozen at −20 °C. These species can still be conserved by seed banking but require alternative storage temperatures that may be identified using differential scanning calorimetry.
Karen Sommerville
Seed processing and germination
Mr James Wood presented on how efficient germination from seed is a critical point for many programs, and the most effective approach to supporting genetically diverse restoration or revegetation outcomes. James touched on how, for seed banks, germination is the most meaningful measure of viability, and the path required to achieving their fundamental purpose. With up to 70% of species worldwide estimated to possess James Wood some type of seed dormancy, James’ key message was that seed dormancy is not a bug but a feature of seeds, reflecting the diversity of habitats and niches these species inhabit. These traits are often an important part of a plant’s lifecycle, ensuring that seedlings emerge at optimal opportunities for establishment, or for achieving persistence in soil seed banks. James also provided a brief review of the current scientific understanding of germination and seed dormancy, and why seed can fail to germinate. This included an explanation of practical approaches to germination testing by outlining the work of the Tasmanian Seed Conservation Centre, including case studies of native species and the resources available to support their conservation and use. Seed researchers still have much to learn, and require more time to do so. Successfully unlocking seed dormancy is typically achieved through a stepwise process of testing. James indicated that we must acknowledge that successful germination is only the beginning of the process for achieving successful establishment of species. There is still much work to do once dormancy is unlocked, but overcoming it is essential to addressing these further challenges.
James Wood
Native orchids
Dr Jenny Guerin presented on how threatened orchid populations have become increasingly fragmented throughout the Mount Lofty Ranges, primarily due to loss of habitat. Ex situ conservation of orchid seeds and associated mycorrhizal fungi is crucial to preserving the remaining biodiversity still present within these isolated populations.
The South Australian Seed Conservation Centre (SASCC) has been collecting and banking threatened flora since 2003. To date over 80% of the state’s threatened plant species are conserved in long-term storage. Conservation of orchid species has become a focus in recent years, starting with a trial project in 2016 funded through NGOs.
Orchid conservation techniques such as seed collection, fungal isolation, seed germination and long-term germplasm storage have been successfully trialled within the facilities. The SASCC currently has dedicated projects to conserve several orchid species in the region in partnership with the Hills and Fleurieu Landscapes Board, councils and private landowners. The program now includes surveys to confirm population status and trends, plant propagation and translocation, as well as ex situ conservation. Case studies will be used to highlight different approaches for conserving individual orchid species.
Jenny Guerin
Special collections
Mr Tom North provided delegates with an explanation on what ‘special’ collections are, such as germplasm material from ferns, mosses and liverworts, or others that have ‘special’ life history stages or growing requirements, such as carnivorous and parasitic plants. Collectively these groups are under-represented in conservation collections but through an understanding of the physiology of the tissues selected for Tom North preservation, or of the special requirements of the plants, ex situ collections of these species are achievable. Tom illustrated how working with these types of collections can mean a wider range of species are made available for use in rehabilitation, reintroduction and ecological restoration, as well as in horticulture and living collections. Tom introduced techniques for the collection, curation, storage and propagation of plants with ‘special’ types of germplasm. This includes treatment of germplasm from non-seed-bearing land plants, spores, gametophytes, shoot tips gemmae and pollen. Tom highlighted some aspects of the basic physiology of the germplasm covered and how this and the final use of the germplasm determine which storage conditions may be required.
Tom North
When considering taxa with ‘special’ life histories, such as parasitic, carnivorous, and other under-represented taxa, their conservation is often driven by developing a better understanding of their role in the landscape. Due to the abundance of relatively large, oily seeds (e.g., Santalaceae, Loranthaceae) or very small seeds (e.g., Droseraceae) in this group of plants, some are known to have seeds that present storage difficulties. Since these plants are often threatened by the same processes as many seed-bearing plants, a greater effort to understand their collection, storage and growth requirements will ensure we have a better chance of securing them into the future.
3rd Edition of the Plant Germplasm Conservation in Australia Guidelines
Dr Amelia Martyn Yenson wrapped up the symposium with an explanation of the recent review and development of the 3rd Edition of the Plant Germplasm Conservation in Australia – strategies and guidelines for developing, managing and utilising ex situ collections. The guidelines, which align with the content of the symposium, bring together decades of research and experience in conserving Australian plants in seed banks, botanic gardens and conservation nurseries. These practical, technical, evidence-based guidelines were compiled as a joint project of the ANPC and the ASBP, with funding from The Ian Potter Foundation. She gratefully acknowledged the input of 78 contributors from across the restoration and agriculture sectors, botanic gardens, CSIRO and universities. The Germplasm Guidelines provide a benchmark for best practice and include 50 case studies that provide a snapshot of ex situ conservation actions from planning to collection, curation, and utilisation of germplasm across Australia and New Zealand. The Guidelines take readers through the genetics and practice of acquiring collections and the processes of seed banking, tissue culture and cryopreservation. A new chapter on the role of the nursery is added to a revised chapter on living collections. New chapters on identifying and conserving exceptional species, care of special collections such as orchids, ferns and under-represented species, risk management, and collection maintenance and utilisation have also been added.
Amelia Martyn-Yensen
The Germplasm Guidelines complement the third edition of the Guidelines for the Translocation of Threatened Plants in Australia and the publication of the new Florabank Guidelines for native seed collection and use for Australian restoration practitioners. The trio of publications addresses the need to protect, manage and restore the biodiverse flora of Australia in the face of threats including fragmentation, disease, changed fire regimes, and climate change.
Conclusion
The Congress theme ‘Botanic gardens as agents of change’ empowered delegates to reflect on the role that botanic gardens must play as the world grapples with the twin crises of biodiversity loss and climate change. The long-term conservation of Australia’s native flora will depend on both in situ management and ex situ collections across our network of gardens, nurseries and seed banks. To be successful the botanic gardens community must continue to utilise the collections we hold to ensure the functional diversity of the Australian flora is maintained. We believe resources like the 3rd Edition of Plant Germplasm Conservation in Australia can play a central role in these efforts by providing practical knowledge and techniques that can be replicated across seed banks, nurseries and botanic gardens. By sharing knowledge, expertise and collections, botanic gardens can be the agents of change throughout Australia and New Zealand.
The Germplasm Guidelines are available for free download and are supported by a suite of professional videos as a playlist, Plant Germplasm Conservation in Australia, on the ANPC YouTube channel here. Hard copies of the guidelines can also be ordered from the ANPC website at https://www.anpc.asn.au/germplasm-guidelines-review/.
References
Gallagher, RV. (2022). Mega-challenges for Australian plant diversity: fires, threats and restoring diversity at scale. 13th Australasian Plant Conservation Conference: Seeds to Recovery, Albury, 3−7 April.
Martyn Yenson, AJ, Offord, CA, Meagher, PF, et al. (eds). (2021). Plant germplasm conservation in Australia: strategies and guidelines for developing, managing and utilising ex situ collections, 3rd edn, Australian Network for Plant Conservation, Canberra.
Murphy, HT, & van Leeuwen, S. (2021). Biodiversity: flora and fauna. In: Australia State of the Environment 2021. Australian Government Department of Agriculture, Water and the Environment, Canberra. https://soe.dcceew.gov.au/biodiversity/environment/flora-and-fauna
