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Future Landscapes

Healthy Estuaries

Ki uta ki tai: Mātāpono me te pūtaiao, ngā korero whakamahuki ma te kaitiaki

Assessing the interactions between loadings of different contaminants from freshwaters on the health and functioning of estuaries

Family out walking. Photo: Spid Pye / Truestock

What Are We Doing?

The health and functioning of estuaries are affected by contaminants from freshwater. These contaminants interact with each other, causing cumulative effects that can be difficult to predict. The National Policy Statement for Freshwater Management does not yet include how to assess the interactions of contaminants.

We are working with Sustainable Seas, in partnership with the Ministry for the Environment (MfE), to address this gap.

In case study estuaries, Māori researchers will work with whānau, hapū, iwi and local community groups to identify aspirations for their estuary, and present uses and stressors.

Our Land and Water researchers will estimate freshwater contaminant loads to New Zealand estuaries historically, now, and under a changed climate. Sustainable Seas will then combine the data with information on estuarine ecology to determine critical stressor thresholds and buffers that take into account the stressors' cumulative effects, mātauranga Māori, and locally informed objectives. These critical stressor thresholds will be used to establish limits for freshwater contaminants.

Our Land and Water will then assess whether implementing different land management options can meet the proposed limits – now, by 2050, or by 2100.

Photo: Spid Pye, Truestock

How Can The Research Be Used?

  • Informed by mātauranga Māori, this mahi will identify contaminant thresholds required to restore the ecological structure and function, and the mauri of estuaries.
  • The research will assess the impact of identified contaminant thresholds on catchment land use, and whether thresholds can be achieved considering realistic land-management options.
  • Health indices and tohu will be identified to inform the management priorities for enhancing estuarine functionality and its mauri.

Community Involvement

  • Research will focus on the Kaipara, Waihi and New River estuaries. These case studies represent different estuary types and sizes with different surrounding land uses and climates.
  • The collaboration with the Ministry for the Environment is a critical part of extending this research nationally. This will include spatial and temporal ecological analyses in 12 estuaries nationwide, and landcover and freshwater input assessments for over 200 estuarine systems all around New Zealand.

Team Snapshot

Research Outputs


Have a Question?

We are happy to answer any questions about this research and how it can be used.

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