Rotorua Uwhi (harakeke weed mats)

  • Name of case study: Uwhi (harakeke weed mats) in Rotorua Te Arawa Lakes
  • Location of case study: Lake Rotoiti, Lake Tarawera, Lake Rotomā, Kaikaitāhuna [Hamurana Springs]  – Rotorua, Aotearoa New Zealand
  • Year of implementation: 2021
  • Scale:  Landscape scale
  • Area / size: Each uwhi is 2.5 by 5m 
  • NbS employed: Uwhi (harakeke weed mats) – Mātauranga Māori/Māori Ecological Knowledge 
  • Type of NbS: Management/social/political – Ecosystem protection – Ecosystem restoration 
  • Ecosystem type: Lake, Spring
  • Initiator: Te Arawa Lakes Trust 
  • Funder: Toitū Te Whenua Land Information New Zealand
  • Design group: Te Arawa Lakes Trust and Local weavers from Te Roopū Raranga Ki Rotorua 

Figure 1. Te Arawa Lakes Trust kaimahi and Te Roopu Raranga Ki Rotorua members watch on as Ngāti Rongomai rangatira Tukiterangi Curtis performs a blessing over the uwhi. Photo/Stephen Parker

Climate change benefits:

  • Decreased pests / spread of weeds
  • Increased food production
  • Increased water quality

Societal / socio-cultural benefits: 

  • Biodiversity health and conservation
  • Food security and quality
  • Water security and quality
  • Mana (pride), whakamana (empowerment), tino rangatiratanga (sovereignty)
  • Cultural diversity and history 
  • Education and knowledge

Ecological benefits: Which ecosystem services are generated or supported?

  • Biological control (regulation of pests and disease)
  • Food production (for humans)
  • Fresh water
  • Habitat provision
  • Species maintenance

Figure 2. Uwhi. Photo/Mark Taylor 

Summary of case study

Te Arawa Lakes Trust have implemented a restoration project using a mātauranga Māori technique called uwhi; weed mats woven from harakeke, to combat an invasive weeds such as lagarosiphon which have significantly degraded the habitat for native species and the water quality of Te Arawa lakes. Similar to weed mats used on the whenua (land), uwhi are laid down and secured to the lakebeds, stopping sunlight from reaching the invasive weeds, preventing photosynthesis and therefore suppressing their growth. This allows for native species and traditional kaimoana (food) such as kōura (crayfish), tuna and kākahi (freshwater mussels) to repopulate the lakes. A co-benefit is that as the harakeke gradually breaks down it provides a nutrient base for the native seed growing water plants (RNZ).

The project has been a milestone for Te Arawa Lakes Trust’s sustainability kaupapa in utilising a Māori approach to weed management and is a prime example of drawing on Māori traditional ecological knowledge and methods to create and test a contemporary solution (Te Arawa Lakes Trust).

Te Arawa Lakes Trust expert divers have regularly monitored the progress and effectiveness of the mats laid down in Lake Rotoiti, Lake Tarawera and Lake Rotomā. After a successful 12-month trial which resulted in a consistent decrease in pest weeds across the three lakes, uwhi have now also been laid down in Kaikaitāhuna (Hamurana Springs) (Te Arawa Lakes Trust).The project is not only restoring the health and mauri (life force) of the lakes and regenerating kaimoana but has also created jobs for the local community, many of whose livelihoods have been impacted by Covid 19. Te Arawa Lakes Trust received funding from Toitū Te Whenua Land Information New Zealand’s Jobs for Nature fund to support the project, which has provided employment for local expert weavers to make the uwhi with the support of  Te Roopu Raranga Ki Rotorua (Te Ao Māori News). The uwhi are made using locally sourced Harakeke, a native flax which has been used by Māori for over 800 years.  Harakeke itself is an abundant natural resource with many uses, known for its durability and versatility, used in medicine, cooking, weaving, whatu, netting, fishing, and hunting (Te Arawa Lakes Trust)

Uwhi is a low-lost, locally sourced and produced native alternative to imported hessian mats. The mats will also provide longer term economic benefits by reducing the need for costly pest control.

Figure 3. Cory O’Neill Te Arawa Lakes Trust places the new uwhi on the bed of the stream. Photo/ Stephen Parker.

References

Links to further information