Seed Conservation

DRBNats, 12 APRIL 2024

Dr Crawford is a research scientist at the WA Herbarium and is responsible for the Threatened Seed Centre. His expertise lies in ex-site seed conservation, which includes seed collection, storage, and longevity. He specializes in seed dormancy and germination of the collection. He offered us insight into the collection’s work.

WA has over 12,500 native species, not all of which need to be collected. About 70% of the native vegetation in southwest Australia has been cleared, and our corner of the continent is considered one of 26 international biodiversity hotspots. The collection has 3,500 WA species of conservation significance: 443 threatened species, 3461 priority species, and 16 species expected to be extinct.

In the Darling Range, we have 44 threatened species and 197 priority species. Conservation is best done on-site where possible; however, with human intervention, that is not always possible, so banks like the Threatened Flora Seed Centre are necessary. There are two vaults: Kensington and Kings Park. The Kensington site is in a purpose-built facility, and it has primary responsibility for conserving WA’s significant plant species.

What is a conservation seed bank? Dr Crawford explained that the facility stores high-quality genetically representative collections of seeds. Some are collected for species recovery and stored under control conditions to maintain seed stability for the future. Dr Crawford spoke on the process: not taking more than 20% of the seed, with attention to avoid weed or disease spread; aiming to have 95% genetic diversity in a population; where more than one population is known, seeds are collected at all sites. Dr Crawford gave several examples of successful collection and translocation back. Once collected, the preservation process is vital. Two factors were significant: temperature and moisture, to avoid unnecessary germination. Using the example of a grasstree seed (Xanthorrhoea preissi), he showed how different preservation methods could extend the seed’s life from four years in an air-conditioned room to over 3000 years if dried and held in a freezer. 

So, how successful has the seed collection been? Kensington has over six thousand seed collections: 80% of the 443 threatened species and 20% of the 3461 priority plant species. Translocating back to the wild of 50 species using seed has been successful. Why is it needed?

An example is that Grevillea batrachoides had only one population in 2002 of over 100 plants – now only 19 remain.

Image by Murray Fagg, Atlas of Living Australia

Close-up of a plant with a red flower Description automatically generated

The seed will be necessary to maintain its genetic diversity. In 2024, a translocation was established in Lesueur National Park after a lightning strike fire in 2011. Fifty seedlings germinated after the fire; with further plantings in 2012, around 100 plants exist. More examples were provided, and everyone was interested in asking more questions as Dr Crawford finished his talk.

Arlene Quinn