Research led by Victoria University of Wellington’s Dr Monica Gerth in collaboration with iwi has discovered molecules from New Zealand native plants could hold the solution to kauri dieback.
Kauri dieback is one of the biggest crises ever to face New Zealand’s forests. If we lose kauri, we lose not only a unique ecosystem but also a key part of New Zealand’s identity, history and culture.Dr Monica Gerth
“Our research has discovered that some compounds found in kānuka cause an immediate loss of motility or movement of the infectious spores of the microbe that causes kauri dieback disease,” says Dr Monica Gerth from the University’s Centre for Biodiscovery and School of Biological Sciences. “If the spores can’t swim, they can’t make it to a kauri root to infect. These compounds could stop this pathogen from moving through soil and infecting kauri trees.”
These results came from a new collaboration between scientists and kaitiaki from iwi, Dr Gerth says, after colleague Chris Pairama (Te Taoū, Ngāti Whātua, Waimauku) connected the research team with Ian Mitchell (Te Uri Taniwha, Ngāpuhi, Waima).
“Being from the north where kauri is common, Ngāpuhi have extensive knowledge about kauri and how plants interact with the forest, and we hoped that we could combine their mātauranga Māori and our scientific knowledge to address the serious problem of kauri dieback disease.”
She says Ngāpuhi knowledge and experience shows that a healthy forest involves three stages of plants – ‘first wave’ plants that cleanse and prepare the soil, ‘second wave’ plants that encourage fertility and growth and ‘third wave’ plants, including kauri, that bring permanence and stability.
The research group studied four ‘first wave’ plants – kānuka, karamū, kawakawa and nīkau – to see if the cleansing activity of these plants was due to anti-microbial properties, Dr Gerth says. In the end, testing showed that kānuka extract was most effective at stopping the pathogen.
Mātauranga Māori and scientific knowledge were combined at every stage of this project, and collecting and testing the plants was a collaborative effort, Dr Gerth says.
“This project was about mutual trust and collaboration, and it was very important to us to create an ethical collaboration. These plants are taonga to Māori, and therefore the right of mana whenua to practise kaitiakitanga (stewardship) should be acknowledged and respected.”
Dr Gerth and her colleagues hope to continue their search for new compounds while also exploring how their findings can be applied to protect kauri trees in the field.
The Connected article Kauri dieback provides information about the kauri dieback disease cycle and how it spreads. It also explains how mātauranga Māori and rongoā may provide insight on how to protect kauri from the deadly spores.
Kawakawa, one of the plants the team investigated, is a versatile plant used in rongoā. Learn more about the research of a high school student who investigated kawakawa as an anti-bacterial agent in the article The science of rongoā.
Take a closer look at trees in these resources: New Zealand native trees – an introduction, What is a tree?, Trees and ecosystems, Trees and natural cycles and Our native trees, a recorded PLD session that introduces useful resources and activities about New Zealand’s native trees.
The paper detailing the research led by Dr Gerth was published in the Journal of the Royal Society of New Zealand. The manuscript is freely available online here.
Learn more about scientist Dr Monica Gerth in this Curious Minds profile and read about her work on the Unlocking Curious Minds project Te Kura o te Kauri, a project that aims to inspire students to become the next generation of kaitiaki o ngahere (guardians of the forest). You can also follow this project on their Facebook page @kauri.classroom.
For detailed information and updates on the fight against kauri dieback, have a look at the Kauri Dieback Programme website. The Kauri Dieback Programme is a partnership with Biosecurity New Zealand (part of the Ministry for Primary Industries), Department of Conservation, Te Roroa (tangata whenua for Waipoua Forest), Tangata Whenua Roopu (representative body for iwi/hapū with an interest in kauri lands) and a number of regional councils.
The Science Learning Hub acknowledge Victoria University of Wellington for permission to publish this article.
In addition to Dr Gerth, Mr Mitchell and Mr Pairama, the cross-disciplinary research team included Dr Scott Lawrence from the University of Otago, Professor Nigel Perry and Ms Elaine Burgess from Plant & Food Research, Associate Professor Wayne Patrick from Victoria University of Wellington and Dr Amanda Black from Lincoln University.
The research detailed in this article was funded by the Ministry of Business, Innovation and Employment.