Mitigation systems

Developing techniques for protecting, enhancing and rehabilitating the biodiversity of freshwater ecosystems and the cultural value they provide.

This programme is developing techniques for protecting, enhancing and rehabilitating the biodiversity of freshwater ecosystems and the cultural value they provide.

Many of New Zealand’s aquatic ecosystems, and their ecosystem services, are in a degraded and often worsening state, causing concern to public and Maori, and threatening tourism and national branding. Protection and rehabilitation of aquatic ecosystems potentially has large economic, environmental, cultural and social benefits including: biodiversity, health and well-being of iwi (mahinga kai, kaitiakitanga, co-management); recreational use and resource recovery, ecosystem services, pure clean-green market advantage for primary products and tourism, and mitigation of urban and rural land-use and climate change impacts.

Our science aims to support the protection, enhancement and rehabilitation of freshwater and estuarine ecosystems. Our work is focusing on improving our understanding of aquatic biodiversity to support protection and conservation of vulnerable species. We are also working on better tools to reduce contaminant loading on aquatic systems and to overcome habitat bottlenecks to rehabilitation. Our research also includes evaluating techniques to overcome hysteresis, i.e. ecosystems not responding once the original stress factors which caused problems are removed.

The programme leader is Dr Fleur Matheson


Taonga species, life history and genetics

  • Determine how human alterations to river habitats and connectivity create habitat bottlenecks which compromise reproduction and colonisation success of freshwater organisms
  • Undertake fundamental research into the cumulative effects of multiple stressors on the dynamics of cultural keystone species focusing on susceptible juvenile lifestages
  • Use state-of-the-art satellite tracking to identify the oceanic spawning locations of New Zealand’s iconic freshwater fish species.
  • Use next-generation DNA techniques to decipher the population genetics of native freshwater species and identify indicators of groundwater biodiversity and ecosystem health.

Citizen science & long-term monitoring

  • Support and harness the collective power of citizen scientists to quantify the effects of stream restoration projects
  • Use long-term ecological monitoring sites to quantify stream water quality and biodiversity responses to sustainable land management activities in forestry, dairy and drystock landscapes.

Rehabilitation techniques 

  • Develop techniques to better target and enhance the performance of edge-of-field mitigation technologies for improved water quality and biodiversity outcomes
  • Trial habitat manipulation techniques to understand and overcome the physical, chemical and/or biological barriers to restoration.

Current research projects

Key science collaborators

AgResearch Bay of Plenty Regional Council Cawthron Institute DairyNZ Department of Conservation ESR Environment Canterbury Greater Wellington Regional Council Hawkes Bay Regional Council Kitson Consulting Kusabs & Associates Lincoln Agritech Living Water Manaaki Whenua – Landcare Research Massey University Ngāti Hāuā Mahi Trust Tipa & Associates University of Aarhus University of Auckland University of Canberra University of Canterbury University of Michigan University of Otago University of Ruhuna University of Waikato Waikato Regional Council Waikato River Authority


See a list of our recent publications

Primary NIWA team:

Dave Allen, NIWA
Data gathered by other citizen scientists can make a big difference to improving water quality around New Zealand. [Photo: Dave Allen, NIWA]