He reo nō te puehu – A voice from the dust
How do you know what a roto (lake) looked like 1,200 years ago? The answer is in the puehu – the dust, silt and pollen that entered the lake and very slowly built up over time.
Looking back in time – Lake Moawhitu
Professor Rewi Newnham tells us about his work as a palynologist – someone who studies ancient pollen – and what this evidence tells us about te ao tuatahi – the world before people arrived.
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Lakes380 – Our lakes’ health: past, present, future is a nationwide project to sample 10% of 3,800 lakes in Aotearoa over 1 hectare (about the size of a rugby field) in size. The Lakes380 team collected sediment cores from the bottom of each lake. Everything that happens in or around the lake leaves a trace in the sediment. As the sediments build up millimetre by millimetre, they create an environmental history of the lake and its surroundings.
Lake Moawhitu
Lake Moawhitu is located on Rangitoto ki te Tonga D’Urville Island in the Marlborough Sounds. It is a coastal lake and was once an important source of mahinga kai for local iwi Ngāti Koata. Mātauranga and oral histories from Ngāti Koata have provided a picture of the roto and its catchment from when their tūpuna settled in the area. Evidence from sediment cores are able to support the oral histories and look even further back in time, before people were present in Aotearoa and around Lake Moawhitu.
The historical scientific data we collected in lake sediment cores has shown us what the lake would have looked like, including the vegetation surrounding it and the animals that lived in it, and the oral histories helped us understand the relationship the people of Ngāti Koata have with Moawhitu.
Restoring the mauri of Lake Moawhitu
Due to significant changes in the catchment, the mauri (health) of the lake has been in decline for many decades. Ngāti Koata Trust and the Department of Conservation have teamed up to improve the water quality and restore the lake ecosystem. This upholds the concept of te mana o te wai – if we take care of the water, it will take care of us.
The Lakes380 team is providing data to help inform these efforts. Information from the sediment cores showed that, prior to human arrival, podocarp (rimu, kahikatea and mataī) and beech forest were abundant in the region. Pollen grains from flax were also in the cores, and local mātauranga identified the species as wharariki. This knowledge from the past creates a more accurate (and likely successful) restoration plan.
Working together to restore Lake Moawhitu
The Ngāti Koata Trust and Department of Conservation are engaging in a collaborative project to improve the mauri of Lake Moawhitu – with the help of Lakes380.
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Kotahitanga, or collaboration, is important for lake restoration because a lot of work is involved, and it can take a long time. Ngāti Koata Trust and the Department of Conservation are leading catchment restoration work that includes hands-on planting of native vegetation. It also has a virtual component where Ngāti Koata Trust and Lakes380 have used mātauranga and scientific data to build a browser-based virtual experience: He reo nō te puehu – A voice from the dust. Users can visit four virtual 360-degree worlds: Pre Human, Māori Settlement, Present Day and Future 2122. Each world contains videos, pop-ups with images and facts and immersive experiences in the roto and on the whenua. The virtual worlds illustrate how much the lake and catchment have changed but also inspire hope about restoring the area and its links with mahinga kai.
Future vision – restoring Lake Moawhitu
Matt Hippolite and Noela McGregor are working to restore Lake Moawhitu. They tell us about their connections with the lake and their feelings of responsibility in returning it to its natural state.
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Creating connections
He reo nō te puehu – A voice from the dust has been instrumental in creating a number of connections. It connects tangata whenua Ngāti Koata with their roto as it once was – and may possibly be again. It makes connections between mātauranga Māori and conventional science – enhancing both knowledge systems. It also shows how innovative and effective science communication can create meaningful connections with a wide audience.
The project also highlights whakapapa – relationships between things within an ecosystem. At Lake Moawhitu, Ngāti Koata relied on tuna for food and plants that grew around the lake for clothing, shelter and tools to catch tuna. Tuna relied on aquatic plants growing in the lake and the pristine water that was cleansed by the ngahere (forest) growing around the lake. The wairuatanga (wellbeing) of all things relies on these connections and the correct balance between them. That’s the vision at Lake Moawhitu – to restore this balance in order to restore the mauri of the lake.
This virtual reality experience really brings the restoration kaupapa to life in a powerful way – you can see for yourself how majestic the lake was and the stark contrast of how degraded it has become, but it also presents an exciting vision of what the future could hold if we continue with our restoration work. This gives us hope for the future of Moawhitu as a significant mahinga kai once again.
