Botanic Gardens Trust, Sydney, Australia


Rainforest Seed project reports

Rainforest Seed Project 2011-2012

Cathy Offord - Manager Horticultural Research and Graeme Errington - Seedbank Officer for Rainforest Project

The Rainforest Seed Conservation Program marks a new phase in our focus on the conservation of Australia’s flora. We have achieved a high level of success in collecting and storing seed from species occurring in NSW, with more than 50% of NSW species represented in the Seedbank. Techniques for the collection and storage of seed from dry environments are well developed and effective as a long term conservation strategy and the collection of seed from these ‘orthodox’ species is ongoing. Many of the seeds of species from wetter environments such as rainforests are not suited to drying and freezing and are termed ‘recalcitrant’. Critical to maximising seedbanking efforts, we are screening species for orthodoxy and developing alternative ex situ conservation techniques for recalcitrant species.

Although many rainforest plants have seed that is not tolerant of desiccation, there may be as many as 50% of species that and can be classified as orthodox. Recent research by Dr Kim Hamilton and Dr Cathy Offord assessed a number of plant characteristics for predictive value of seed desiccation tolerance. The Rainforest Seed Conservation Program involves the use of the results of this research to assist in the identification of seed that can be collected and stored. Seed from species for which the desiccation sensitivity is not known will be collected and assayed and this information will contribute to the ongoing international research into the seed biology of rainforest flora. As with the collection of orthodox species, there will be a particular focus on the collection of seed from threatened species.
Rainforests are significant reservoirs of plant biodiversity. Although rainforests cover only 0.3% of Australia’s land area they contain 50% of plant species, and are significant habitat for a range of threatened plants and animals. Climate change and other threats such as weed invasion and habitat fragmentation are placing increased pressure on these areas. The latest threat to Australia's Rainforest Flora is the arrival and spread of the disease myrtle rust. Several species have been identified as being particularly susceptible to myrtle rust including species of Rhodamnia, Rhodomyrtus, and Archirhodomyrtus. Rhodamnia rubescens is a relatively common species and has been particularly badly affected by the disease with severe defoliation and damage to flower and fruit production. The seed storage behaviour of these species has not been assessed and an appropriate conservation strategy is dependant on this information. Where possible we will be making collections and assessing seed from affected species and storing suitable seed. Techniques such as tissue culture and cryostorage are being investigated for threatened species with recalcitrant seeds.

This program aims, over the next three years to collect, assess and store 145 species of rainforest plants. During the past collecting season 58 collections of rainforest species were made, 19 collections were placed directly in storage and the remainder are being further assessed.

A number of collection trips were conducted across the year to take advantage of the extended flowering and fruiting of rainforest species. The ripening of fruits in orthodox species tends to occur as a peak during the late spring and early summer period, whereas the flowering and fruiting in rainforest species has a more even spread across the seasons extending the opportunities for collection and allowing for timely processing of the deteriorating fruits. The program will focus on the far north coast of New South Wales with its high level of diversity, including locations such as the cool-temperate rainforest of the Border Ranges and the remnants of Critically Endangered Lowland Rainforest of Subtropical Australia. Other important areas include the dry rainforests of western NSW, the subtropical rainforest of the Dorrigo area, and littoral rainforests along the coast

Rainforest Seed Project 2010-2011

Dr Cathy Offord – Manager Horticultural Research and
Dr Kim Hamilton -  Rainforest Seed Project coordinator and postdoctoral scientist

The rainforest regions of Australia are relatively small in size but are estimated to contain more than 50% of Australia’s biodiversity. Under carefully controlled conditions, most Australian seeds can be conserved for decades and in many cases, centuries, however plants from rainforests and wetter areas are very difficult to dry and therefore store. The Rainforest Seed Project systematically appraised the potential for storage of seed of Australian rainforest species. It is not possible to simply look at the seeds of a rainforest species and determine whether or not it may be stored. Prior to this project seed storage of rainforest species has been a matter of trial and error with a paucity of reliable information.

This project is the first important step in understanding which rainforest plants can be stored as seed, and to offer alternatives for those that cannot. Through this process this we will contribute to the sum of knowledge about how to conserve our vulnerable flora. Understanding rainforest seed biology does not stop at seed storage. Important information generated by the project on specific seed germination conditions and requirements can contribute to management of rainforests species in their natural habitats.

The broader scope of this project has international significance as we are contributing information to a global effort to understand the seed biology of rainforest flora being coordinated by colleagues at the Royal Botanic Gardens, Kew. We are also increasingly delivering seed conservation training in Australia and in south-east Asia.

In the NSW Seedbank, we now have representatives of around 40% of the State’s species. The Rainforest Seed Project is key to our ten year goal to store and preserve all NSW plant species, including rainforest species, primarily as seed, or in tissue culture, cryostorage and as living plants in our collections. In our program: 

  • We have collected and screened over 160 rainforest species.
  • This included over 50 endangered (or near relative) species.
  • We are investigating the tissue culture requirements of a number of highly endangered rainforest species.
  • Three papers have been submitted to peer-reviewed journals this year.

Rainforest Seed Project 2008-2009

Conserving Rainforest Seeds

Dr Kim Hamilton - Rainforest Seed Project coordinator and postdoctoral scientist and Dr Cathy Offord - Manager Horticultural Research

One of the key risks of projected climate change is its effect on Australian rainforests. Climate change is predicted to interact with other threats, such as weeds and habitat fragmentation, in some of the most vulnerable environments like the Gondwana Rainforests of Australian and the Wet Tropics. Seed banking is a cost effective way of conserving vulnerable species outside of their natural habitat, but not all species, especially many rainforest species, can survive the seed banking procedure that requires tolerance to seed desiccation.  To contribute to the conservation of threatened species in the wild, the Royal Botanic Gardens Foundation has funded the Rainforest Seed Project for 3 years (May 2008 - May 2011) through generous donations from Allianz, Tony Maxwell and Robyn Godlee.

The Rainforest Seed Project investigates the seed biology, particularly desiccation sensitivity, of eastern Australian rainforest species with the aim of contributing to in situ conservation. The seed biology data will also be analysed to increase our understanding of ecological correlates of seed desiccation sensitivity for predictive use in rainforest species. For species identified to have seed desiccation sensitivity, in situ conservation and technology development (e.g. cryostorage) needs to be prioritised.  The findings of the project will be collated into a readily accessible database for use by scientists and restoration practitioners to inform their work (e.g. revegetation and seed banking).

The project objectives are to:

  1. Screen rainforest species to determine whether they can be stored by conventional seedbanking
  2. Improve understanding of germination and seedling establishment in rainforest species
  3. Work in close collaboration with local (Southern Cross University), national (Environmental Futures Centre, Griffith University) and international scientists (Millennium Seed Bank, Royal Botanic Gardens Kew) for improved scientific understanding and conservation of rainforest species worldwide
  4. Develop conservation technologies, including tissue culture and cryostorage for recalcitrant species.
  5. Collate findings into a readily accessible database for access by scientists and restoration practitioners to inform their work (e.g. revegetation and seedbanking).

The Rainforest Seed Project is part of SeedQuest NSW based at the Australian Botanic Garden Mount Annan (Royal Botanic Gardens & Domain Trust , Sydney) in partnership with Millennium Seed Bank, Royal Botanic Gardens Kew and contributes to the Global Strategy for Plant Conservation and Priority Action Statements / recovery plans for threatened species. To date seed biology testing has been investigated for 75 significant and/or threatened rainforest species from 30 plant families. In addition, about 20 newspaper articles, 5 radio interviews (Dr Tim Entwisle), 2 magazine articles, 1 ABC website ‘Scribbly Gum’ article, 4 papers, 1 book chapter and 4 conference presentations have disseminated the objectives and acknowledged the importance of this project and sponsor contribution. 

Harnieria hygrophiloides ripening seed pods during late spring/early summer

Celastrus subspicata fruits

Harnieria hygrophiloides flower

All images: Graeme Errington

Toechima dasyrrhache. Photo: K. Hamilton

Rainforest fruits of eastern Australia. Photo: S. Cottrell

Rainforest fruit collection for seed biology testing. Photos: K. Hamilton

Amanda Rollason collecting fruits of Acronychia laevis. Photo: S. Cottrell

Rhysotoechia robertsonii


Thermal analysis of phase transitions in seeds, using differential scanning calorimetry, to determine optimal moisture content for seed cryopreservation.

Dr Kim Hamilton operating differential scanning calorimeter of the Millennium Seed Bank (Royal Botanic Gardens, Kew) in the UK. Photo: L. Butler