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  Community » Waikato Progress Indicators - Tupuranga Waikato » Report cards » Coastal habitats

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worsening trend    WORSENING TREND


Increasing amounts of the pest plant, saltwater paspalum are invading estuaries on both coasts in the Waikato region.

This indicator measures the estuarine area in the Waikato region which is covered with invasive species (saltwater paspalum) on the east coast and west coast.

Why is this indicator important?

Saltwater paspalum is an invasive coastal plant which is a perennial grass that forms dense mats along the margins of tidal flats or on sandy or gravel beaches. It is also known to spread into nearby pasture and coastal dunes. In New Zealand estuaries, saltwater paspalum invades and changes the composition and structure of native ecosystems. As a result, it can reduce or exclude feeding and roosting sites for birds, and may alter fish spawning and feeding grounds. It can also affect water quality in our estuaries by increasing the amount of sediment in their waters.

In the Waikato region, saltwater paspalum is well established along the Coromandel Peninsula, northern Waikato, outlying islands and Raglan harbour. There are manageable infestations within Kawhia and Aotea harbours, where Waikato Regional Council has a long term objective to achieve zero density of saltwater paspalum.

Monitoring pest plants throughout the Waikato region, including on our coasts, helps councils and other organisations and environmental groups identify and manage this vegetation effectively.


What is this indicator telling us? 

  • Between the 1997-1999 and 2007-2009 monitoring periods, the number of hectares of invasive saltwater paspalum on the east coast of the Waikato region increased substantially.
  • Similarly, between the 2005 and 2012 surveys on the west coast, there was a significant increase in the area of saltwater paspalum.

Check out related information on our website and other organisations’ websites listed on our Waikato Progress Indicators’ Useful Links page.

Click here to view report cards



Data sourced from Natural Solutions – Marine & Terrestrial Ecologists. Due to technology improvements (e.g. digital aerial mapping), caution should be taken when comparing older and newer data.

Update details: Monitoring to date has been approximately 7-10 year cycle for each coast successively.

Customised data request requirements: Request is for hectares of estuarine area covered with invasive species (saltwater paspalum) on the east coast and west coast.


Territorial Authority (TA) disaggregation: No

Other regions: No

New Zealand: No

Other countries/ Organisation for Economic Co-operation and Development (OECD): No




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