New Zealand's native trees and bush can't all be saved through seed banking, a new study shows.
Twenty-one percent of New Zealand's trees and shrubs - including species such as totara, rimu and tawa - have "recalcitrant" seeds. That means they don't survive the drying and freezing process involved in seed bank storage.
Lead author Sarah Wyse says Kiwis can't rest on our laurels thinking seed banks are a silver bullet.
"We need to mind that we have quite a few plants that won't be able to be saved in this way, and try and find alternative methods. One that we've talked about is cryopreservation."
Cryopreservation involes removing the embryo from the seed to freeze in liquid nitrogen. It's a much more complicated process than normal seed banking, but not all precious and threatened species - such as kauri - can be saved in this way.
"Although we can dry it and we can freeze it, it's very short-lived. It's not practical to save it in a seed bank - how do we try and preserve the species outside of its habitat?"
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Kauri seeds aren't recalcitrant, but last fewer than 10 years - so seed banks are useless.
Dr Wyse says unless we invest more research into alternative conservation efforts, we will lose them and other species, especially in the event of a catastrophe.
There's an international goal of conserving 75 percent of the world's threatened species away from their natural habitat.
"If we are serious about wanting to save our unique trees, we need to do everything we can to save them in their natural environment, because other methods may simply not work."
The Svalbard Global Seed Vault in Norway is designed to survive even a nuclear war, and has been collecting seeds from around the world since 2008.
The research was carried out in the UK and New Zealand, and published in journal Nature Plants.
Newshub.
