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  • New research details the history of raupō from the time before people arrived in Aotearoa1. It shows this resilient, opportunistic plant – and taonga species2 – can play an important role restoring wetlands3 and freshwater quality.

    This article has been republished from The Conversation under Creative Commons licence CC BY-ND 4.0 and is written by Rewi Newnhan, Professor in Physical Geography, Te Herenga Waka – Victoria University of Wellington. It was originally titled The common raupō once kept NZ’s wetlands and lakes thriving – now it could help restore them.

    With about 90% of New Zealand’s natural wetlands drained or severely damaged during the past decades, we need to understand the role of native4 plants in the restoration of these important habitats5.

    Rights: Martin Rady, CC BY 4.0

    Raupō

    Raupō (Typha orientalis) is a resilient plant and acts as an ecological buffer. The plants develop distinctive flower spikes.

    Image sourced from iNaturalistNZ.

    Our new research details the history of raupō (bulrush) from the time before people arrived in Aotearoa. It shows this resilient, opportunistic plant – and taonga6 species7 – can play an important role restoring wetlands and freshwater quality.

    An unexpected finding was that the decline8 of freshwater quality in many lakes did not really kick in until the mid-20th century with intensification of agriculture. Until then, lake water quality indicators generally showed these ecosystems9 remained healthy. The prolific expansion of raupō after Aotearoa was first settled may have helped.

    Thriving on material washed from disturbed catchments, raupō acted as an ecological buffer, intercepting nutrients10 and sediments11, and reducing potentially harmful effects on freshwater ecosystems.

    Rights: © 2024 Li et al. CC BY 4.0

    Raupō response to environmental change

    This schematic shows how raupō responded to environmental changes during the past millennium (upper panels), informed by pollen analysis of lake sediments (lower panels).

    Diagram from: Li X, Newnham R, Vandergoes MJ, van den Bos V, Howarth JD, Rees A, et al. (2024) Insights into the natural and cultural history of Typha orientalis (Raupō) in Aotearoa New Zealand. PLOS Water 3(9): e0000240. https://doi.org/10.1371/journal.pwat.0000240

    From the mid-20th century, as water quality began to deteriorate, raupō populations12 – and any buffering effects – were generally in decline as wetlands and lake shallows were drained for grazing land and better access to water supply.

    Lessons from this plant’s past can be put to good use today as we strive to bring back the mauri13 (life force) of our freshwater systems.

    Survival strategies for hard times

    Before settlement, when dense forest covered most of the country, raupō was surviving on the fringes. As a wetland14 plant, it likes its roots submerged, but needs light to grow.

    Its preferred niche15 is the shallow margins of lakes, ponds and streams or nutrient-rich swamps. Before people, these places were much less common. Forests typically grew right up to the water’s edge and extended across some swamps.

    Under these conditions16, raupō evolved17 strategies for survival: aerated roots to cope with water logging; tiny, abundant seeds that spread far and wide on the wind; rhizomes (underground stems) that extend from the mother plant and store carbohydrates to keep the plant alive in lean times.

    Rights: © 2024 Li et al. CC BY 4.0

    Raupō adaptations

    Raupō has several adaptations that allow it to grow on disturbed land.

    Diagram from: Li X, Newnham R, Vandergoes MJ, van den Bos V, Howarth JD, Rees A, et al. (2024) Insights into the natural and cultural history of Typha orientalis (Raupō) in Aotearoa New Zealand. PLOS Water 3(9): e0000240. https://doi.org/10.1371/journal.pwat.0000240

    Raupō can even build floating root mats, from sediment18 trapped by its rhizomes19, that extend out across open water and even detach from the shoreline to become mobile raupō islands.

    With these survival strategies, raupō could wait for better times which, in Aotearoa’s dynamic20 environment, duly arrived.

    Episodic agents of disruption – storms, floods, earthquakes, landslides, volcanic ashfall – created opportunities. Local forest damage allowed light to penetrate to ground level, and slips and floods brought nutrient-rich sediment from soils.

    Raupō would seize these opportunities to expand. But they were typically short-lived as the inevitable process of forest succession21 returned the environment to stability – and raupō back to a state of patient hibernation.

    Hitting the jackpot

    Then people arrived, with fire and hungry mouths to feed. This time, the disturbances persisted. Forest clearances endured, sediments rich in nutrients flooded wetlands and lakes, and raupō, supremely equipped for just this scenario, spread across swamps and lake shores as wildfires spread on land.

    Our tūpuna22 (ancestors) observed this behaviour, as well as what was happening around raupō. Insects and birds were feeding and nesting. Freshwater fish, crays, shellfish and eel spawned among its fertile beds.

    This new-found abundance also offered a range of resource opportunities. The raupō’s flax-like leaves were woven into mats, rope and string. Leaves and stems were used like thatch to cloak the roofs and walls of whare.

    Traditional poi were often made from raupō leaves. Some iwi23, particularly in the south, used the stems to build lightweight boats for navigating rivers and lakes. Flower stalks, shoots and young leaves were eaten, and the rhizomes and roots, when cooked, provided edible carbohydrates. The most cherished raupō kai, however, were cakes baked using the copious raupō pollen24.

    Rights: Alexander Turnbull Library

    Raupō poi

    The dry leaves of raupō are the traditional material used for covering poi, which are then filled with the fluffy down from the seed heads.

    Image: Mansfield, Katherine 1888-1923 (Collector): Raupō long poi. Late nineteenth century? Curios-018-1-006. Alexander Turnbull Library, Wellington, New Zealand

    Unsurprisingly, for many iwi raupō remains a taonga species today, treasured for this array of resources and for its ecological and even spiritual roles in maintaining the mauri of freshwater habitats, upon which so much depends.

    For some iwi, raupō are seen as kaitiaki25 watching over a lake or wetland, and signalling its health. In these ways, raupō also connects us with other Indigenous26 communities. Although raupō is native to this country, the same species is found in Australia and parts of East Asia, while relatives in the genus27 Typha (Greek for marsh) occur naturally on all continents28, except Antarctica.

    Similar practices occurred wherever raupō and its relatives are found. This connection between cultural and ecological roles is one of the fascinating findings from our research. We describe raupō as a “human-associated species”, not just because of its taonga status, but because its fate seems so closely linked to people.

    More work needs to be done, but history tells us raupō has an important role in restoring the health of our freshwater ecosystems. Not only can it soak up nutrients and contaminants, but as both a native and taonga species it can assist remediation solutions that are ecologically and culturally supportive and sustainable29.

    Related content

    Repo (wetlands) – a context for learning has multiple links to a variety of resources around wetlands from a te ao Māori30 perspective.

    Wetland plants takes a closer look at the flora31 of New Zealand wetlands. The video Repo plants shows examples of mātauranga Māori32 of raupō and the internal structure of the plant.

    If you’d like to plan a unit around freshwater, see Freshwater resources – planning pathways, this includes the interactive Planning pathways using freshwater resources which provides numerous links to student activities, articles and media for use in the classroom.

    This research is part of the Lakes380 project. Lakes380 – a context for learning introduces the project and the resource Lake sediment cores – exploring the past takes a closer look at information that can be gained from the cores.

    In the video Looking back in time – Lake Moawhitu, watch Professor Rewi Newnham talk about his work as a palynologist – someone who studies ancient pollen – and what this evidence33 tells us about te ao tuatahi – the world before people arrived. In Weaving knowledge he discusses some of the different methodologies that underpin conventional science and mātauranga Māori.

    The activity Interpreting lake sediment data uses Lakes380 information sheets to build student understanding of the nature of science34 and the science capabilities.

    Learn more about mōkihi – rafts made from raupō.

    Aotearoa New Zealand’s Ministry for the Environment and Stats NZ report on the state of different aspects of the environment – Our land 2024 details the effects of human activities on our diverse ecosystems and the cascading impacts of our land-use choices. The resource Our land 2024 summarises the report with additional links to educational resources.

    Useful links

    The Ministry for the Environment and Stats NZ report Our Land 2024 has an infographic on page 24, showing wetland loss in Aotearoa New Zealand. It further details how land-use choices are impacting the environment.

    Manaaki Whenua – Landcare Research has a useful resource: Raupō that details the plant physiology35, reproduction and some of the ways humans have used the plant.

    Acknowledgement

    This article was written by Rewi Newnhan, Professor in Physical Geography, Te Herenga Waka – Victoria University of Wellington. This article was originally published in The Conversation, 26 September 2024. Read the original article.

    Rights: The Conversation

    The Conversation

    The Conversation is an independent source of news and views, sourced from the academic and research community and delivered direct to the public.

    The Conversation

    1. Aotearoa: The Māori name for New Zealand, meaning Land of the Long White Cloud.
    2. taonga species: Species or biota that are of value to Māori or hold cultural significance to Māori, which may include introduced species.
    3. wetland: An area of land that is saturated with water, often referred to as a swamp or bog. Wetlands may be seasonally or permanently water-logged with vegetation adapted for life under those soil conditions. Wetlands are known as repo in te reo Māori.
    4. native: A species that lives naturally in a country, as opposed to species that have been introduced by the activity of humans. 
    5. habitat: The natural environment in which an organism lives.
    6. taonga: Within the Māori world view, a taonga is a treasure that represents whakapapa in relation to a kin group’s estate and tribal resources. Amongst many things, a taonga can be a living creature, a landscape, an object or a song. Taonga are important to the mana (honour and prestige) of the iwi associated with them.
    7. species: (Abbreviation sp. or spp.) A division used in the Linnean system of classification or taxonomy. A group of living organisms that can interbreed to produce viable offspring.
    8. decline: The gradual and continuous loss of something such as bird numbers or sea ice.
    9. ecosystem: An interacting system including the biological, physical, and chemical relationships between a community of organisms and the environment they live in.
    10. nutrient: A substance that provides nourishment for growth or metabolism.
    11. sediments: Material that settles to the bottom of a liquid. In geology, it describes the solid fragments of inorganic or organic material that come from the weathering of rock and are carried and deposited by wind, water or ice.
    12. population: In biology, a population is a group of organisms of a species that live in the same place at a same time and that can interbreed.
    13. mauri: Life force or spiritual essence of a person, place or thing.
    14. wetland: An area of land that is saturated with water, often referred to as a swamp or bog. Wetlands may be seasonally or permanently water-logged with vegetation adapted for life under those soil conditions. Wetlands are known as repo in te reo Māori.
    15. niche: The position occupied by an organism in an ecosystem. The niche includes both the organism’s specific physical environment and the role that it plays within the wider ecosystem.
    16. condition: An existing state or situation; a mode or state of being.
    17. evolve: To develop gradually. Changes in successive generations over long periods of time.
    18. sediments: Material that settles to the bottom of a liquid. In geology, it describes the solid fragments of inorganic or organic material that come from the weathering of rock and are carried and deposited by wind, water or ice.
    19. rhizome: Underground stem.
    20. dynamic: In science, a process or system characterised by constant change.
    21. ecological succession: The change in the types of species living in a specific area over time.
    22. tūpuna: Māori term for ancestors.
    23. iwi: Māori tribe or large community, often consisting of several hapū (clans) bound together by common ancestors.
    24. pollen: Dust-like grains that contain male sex cells (gametes) of flowering plants (angiosperms) and cone plants (gymnosperms). Pollen is made on the anthers of flowering plants.
    25. kaitiaki: A person, group or being that acts as a carer, guardian, protector and conserver.
    26. indigenous: Originating and living or occurring naturally in an area or environment. People who are the original inhabitants of an area, or their descendants.
    27. genus: (Plural genera) A division used in the Linnean system of classification or taxonomy. A group of closely related species.
    28. continent: In geology, any of the main continuous expanses of continental crust on the Earth. Africa, Antarctica, Asia, Australia, Europe, North America and South America are recognised as continents, but this is based on historical and cultural attributes rather than geological attributes.
    29. sustainable: A way of using natural products so they are available for future generations.
    30. te ao Māori: Māori world view (belief system), which provides a Māori epistemology (study of knowledge) of source, origin, knowledge, and application.
    31. flora: A flora (with a small f) refers to the plant life occurring in a particular region. A Flora (with a capital F) refers to a book or other work that describes and identifies a flora.
    32. mātauranga Māori: A contemporary term referring to Māori knowledge, Māori ways of knowing and associated practice.
    33. evidence: Data, or information, used to prove or disprove something.
    34. nature of science: The Nature of Science (NoS), is an overarching and unifying strand of the New Zealand science curriculum. Through it, students develop the skills, attitudes and values to build a foundation for understanding the world around them – understanding how science works in order to make links between scientific knowledge and everyday decisions and actions.
    35. physiology: A branch of biology that studies the functions and activities of living organisms, including all physical and biochemical processes.
    Published 7 October 2024 Referencing Hub articles
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        Aotearoa

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      2. The Māori name for New Zealand, meaning Land of the Long White Cloud.

        native

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      4. A species that lives naturally in a country, as opposed to species that have been introduced by the activity of humans. 

        species

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      6. (Abbreviation sp. or spp.) A division used in the Linnean system of classification or taxonomy. A group of living organisms that can interbreed to produce viable offspring.

        nutrient

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      8. A substance that provides nourishment for growth or metabolism.

        mauri

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      10. Life force or spiritual essence of a person, place or thing.

        evolve

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      12. To develop gradually.

        Changes in successive generations over long periods of time.

        ecological succession

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      14. The change in the types of species living in a specific area over time.

        pollen

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      16. Dust-like grains that contain male sex cells (gametes) of flowering plants (angiosperms) and cone plants (gymnosperms). Pollen is made on the anthers of flowering plants.

        genus

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      18. (Plural genera) A division used in the Linnean system of classification or taxonomy. A group of closely related species.

        te ao Māori

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      20. Māori world view (belief system), which provides a Māori epistemology (study of knowledge) of source, origin, knowledge, and application.

        evidence

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      22. Data, or information, used to prove or disprove something.

        taonga species

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      24. Species or biota that are of value to Māori or hold cultural significance to Māori, which may include introduced species.

        habitat

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      26. The natural environment in which an organism lives.

        decline

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      28. The gradual and continuous loss of something such as bird numbers or sea ice.

        sediments

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      30. Material that settles to the bottom of a liquid. In geology, it describes the solid fragments of inorganic or organic material that come from the weathering of rock and are carried and deposited by wind, water or ice.

        niche

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      32. The position occupied by an organism in an ecosystem. The niche includes both the organism’s specific physical environment and the role that it plays within the wider ecosystem.

        rhizome

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      34. Underground stem.

        tūpuna

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      36. Māori term for ancestors.

        kaitiaki

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      38. A person, group or being that acts as a carer, guardian, protector and conserver.

        continent

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      40. In geology, any of the main continuous expanses of continental crust on the Earth. Africa, Antarctica, Asia, Australia, Europe, North America and South America are recognised as continents, but this is based on historical and cultural attributes rather than geological attributes.

        flora

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      42. A flora (with a small f) refers to the plant life occurring in a particular region. A Flora (with a capital F) refers to a book or other work that describes and identifies a flora.

        nature of science

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      44. The Nature of Science (NoS), is an overarching and unifying strand of the New Zealand science curriculum. Through it, students develop the skills, attitudes and values to build a foundation for understanding the world around them – understanding how science works in order to make links between scientific knowledge and everyday decisions and actions.

        wetland

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      46. An area of land that is saturated with water, often referred to as a swamp or bog. Wetlands may be seasonally or permanently water-logged with vegetation adapted for life under those soil conditions. Wetlands are known as repo in te reo Māori.

        taonga

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      48. Within the Māori world view, a taonga is a treasure that represents whakapapa in relation to a kin group’s estate and tribal resources. Amongst many things, a taonga can be a living creature, a landscape, an object or a song. Taonga are important to the mana (honour and prestige) of the iwi associated with them.

        ecosystem

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      50. An interacting system including the biological, physical, and chemical relationships between a community of organisms and the environment they live in.

        population

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      52. In biology, a population is a group of organisms of a species that live in the same place at a same time and that can interbreed.

        condition

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      54. An existing state or situation; a mode or state of being.

        dynamic

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      56. In science, a process or system characterised by constant change.

        iwi

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      58. Māori tribe or large community, often consisting of several hapū (clans) bound together by common ancestors.

        indigenous

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      60. Originating and living or occurring naturally in an area or environment.

        People who are the original inhabitants of an area, or their descendants.

        sustainable

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      62. A way of using natural products so they are available for future generations.

        mātauranga Māori

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      64. A contemporary term referring to Māori knowledge, Māori ways of knowing and associated practice.

        physiology

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      66. A branch of biology that studies the functions and activities of living organisms, including all physical and biochemical processes.