Tipping points in ecosystem structure, function and services

A team set up a tipping points experimental site in Manukau Harbour, one of 24 across New Zealand. © Simon Thrush, University of Auckland

We are investigating how marine ecosystems respond to change, and identifying tipping points, risks and ways of managing them. 

Project leader: Simon Thrush, University of Auckland

Duration: April 2016 – June 2019 
Budget: $3,470,000 
Status: Ongoing 

We are investigating the effects of multiple stressors and cumulative impacts on marine ecosystems. Stressors can be caused by unexpected events (such as earthquakes) or impacts of human activities (such as increased sediment, nutrients or contaminants in the water), or climate change. These stressors can lead to ‘tipping points’ when rapid transformations occur, and an ecosystem loses its capacity to cope with change. Tipping points often involve the loss of valuable marine resources, or ecosystem services. 

This is the first nationwide assessment of how estuaries and harbours in Aotearoa New Zealand respond to change. Our results show that as coastal waters become more turbid and nutrient levels increase biodiversity and ecosystem function decline. Rocky shores and kelp forests are also affected, with elevated turbidity decreasing the ability of these systems to respond to change and recover from disturbance.  

Coastal and marine ecosystems deliver multiple benefits and services, so it is important to deal with the cumulative impacts of stressors and develop management strategies to reduce their impact. Our research suggests there is a growing need to apply an ecosystem-based management framework to manage risk and sustain New Zealand’s coastal ecosystems. This is even more important given the ongoing impacts of climate change.

In the media

  • Tipping Points and the health of estuaries, Our Changing World, Radio New Zealand
    An in-depth piece that gets into the detail of what the Tipping points project is investigating, and why.
  • 50 questions about the environment: Our oceans, NZ Herald, Jan 2018
    Simon Thrush, leader of the Tipping Points project, was interviewed about key issues facing ocean and coastal ecosystems, including threats and pressures like ocean acidification, tipping points, and considerations for marine management.

Journal articles

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