NZ’s estuary health check-up results now freely available online

From today, people can access information about the health of estuaries locally and across the country using a new topic on the LAWA website that makes results from regional and unitary council monitoring programmes freely available.

The new LAWA Estuary Health topic presents environmental data from New Zealand’s largest estuary monitoring dataset, covering nearly 400 monitoring sites across 80 estuaries.

LAWA Estuary Health Science Lead Dr Tarn Drylie said the places where rivers and streams meet the sea are complex, yet there are things councils monitor to understand the pressures that estuaries are under.

“New Zealand’s estuaries are culturally and ecologically significant. We know that many of them are under pressure and the LAWA Estuary Health topic provides results from regional and unitary council monitoring of contaminants, mud content, and estuary macrofauna.

“Estuary health is impacted when concentrations of contaminants like metals and hydrocarbons get too high. From the monitoring data on LAWA, we see estuaries that are most affected by high loads of contaminants tend to be downstream of built-up areas.

“Another important factor for estuary health is the amount of mud content from the surrounding land that is in the surface layers of the sandflats. Higher mud content is found in places with the most modification to land use,” said Dr Drylie.

LAWA also presents the results of regular estuary macrofauna check-ups. Estuary macrofauna include hundreds of intertidal species such as worms, snails, crustaceans, and shellfish like pipi and cockles.

“We monitor the makeup of macrofaunal communities because some critters only live in pristine environments while others thrive in degraded conditions,” said Dr Drylie, “Regular monitoring of estuary macrofauna gives us a good indication of the overall health of an estuary and any changes in conditions over time.”

The estuaries along the coastline of New Zealand come in various shapes, sizes, and state of health.

Dr Chris Daughney, Chief Science Advisor for Te Uru Kahika – Regional and Unitary Councils Aotearoa said estuaries are dynamic and provide a window into the health of the wider catchment.

“Regional and unitary councils monitor estuaries to understand their ecological condition and how this is changing over time, especially in relation to human activities that may degrade them.

“Some regions have been formally monitoring estuaries for three decades, while others have only recently established programmes in acknowledgement of the importance of estuary health for our collective wellbeing.

“The health of an estuary can be impacted by sediment, nutrients, and pollution from land use upstream, marine pressures such as over-harvesting, dredging, and invasive species, shoreline activity and development, and climate change.

“The results from regular monitoring of these highly connected environments help us to understand whether catchment activities and pressures are being managed effectively and direct future management and restoration efforts,” said Dr Daughney.

Estuaries provide several ecosystem services and support water quality through natural filtration and binding pollutants within sediment. They are home to diverse plants and animals, some of which are only found here in Aotearoa.  

Department of Conservation Marine Technical Advisor Helen Kettles encouraged people to explore the LAWA website and get acquainted with their local estuaries.

“Estuaries are truly special places that provide outsized benefits for us and the planet. If we can look after estuaries, they can look after us.

“The new LAWA Estuary Health topic can help us all to better understand our local estuaries and act for them.

“Improving estuary health will take time, so we must continue and extend the good work happening across the motu from riparian planting to reducing the use of pollutants at home and work. I want to recognise everyone that’s involved in estuary restoration and protection,” said Ms Kettles.

LAWA Chair Dr Tim Davie said the LAWA website presents quality data and information collected regionally in a way that is nationally consistent.

“We are delighted to launch the LAWA Estuary Health topic today. This is the eighth topic on the LAWA website, and it helps to connect our water reporting from ki uta ki tai (mountains to sea).

“We all want the same thing; healthy environments for generations to come. To do this we need accessible, reliable, and quality data to help inform restoration efforts and track improvement over time.

“Through the LAWA project, we’re putting environmental data in the hands of researchers, iwi, government, industry, and communities so they can make informed decisions,” said Dr Davie.