How is the Kaipara's health changing?
Students in the Kaipara region are learning how to keep a close eye on the health of their watery taonga using Māori knowledge and scientific estuary monitoring kits.
The Kaipara Harbour is being slowly choked to death by too much sediment in the water, but Te Uri o Hau (Ngāti Whātua) kaitiaki – guardians of the Kaipara – are trying to reverse that.
As part of their work, the kaitiaki are showing the next generation how to use both mātauranga Māori and NIWA’s Ngā Waihotanga Iho monitoring kit to see where the estuary needs help.
Rangatahi from Rodney College joined the kaitiaki for a day at Oruawharo Marae (Ngāti Mauku, Ngāti Whātua) and its nearby inlet.
At the end of the pōwhiri (welcome), Mikaera Miru – who co-leads the project with Unitec Senior Lecturer Giles Dodson and has been kaitiaki of the Kaipara for over 20 years – gave a talk about what the Kaipara was like before modern impacts such as land use changes and overfishing.
“This place once had masses of kai,” he said. “The Kaipara had heaps of fish in it and the birdsong in the forests was deafening. But now the trees have all been cut down, the river’s clogged up and there’s almost nothing left of the environment that was there before.”
The rangatahi and the kaitiaki all then headed down to the inlet to take measurements and learn about how the Kaipara looks now.
The students were then split into four groups who each received a monitoring kit. In the kit was a compass, a tape measure, a GPS locator, a quadrat, a sieve, a trowel and a plant identification booklet.
Each team had a slightly different monitoring task such as logging the different soil types, how widespread the invasive and native plants were, and how much silt built up on a concrete slab placed in the water.
“We measured the boundary of a patch of grass, which we will keep looking at to see if it changes,” 14-year-old Rebekah tells us. “This will help us and future generations know what to do to make the area healthier, like planting more trees.”
While some of the implications from the measurements weren’t immediately obvious, the slab findings were.
“We put the slab in the water about five months ago and today we could see that we’d already got 13 centimetres of silt that had been deposited on it,” says kaitiaki Aleesha Bennett.
“Most of the sediment comes from the upper parts of the Kaipara catchment, between Dargaville and Whangarei, where much of what was once forest and wetland is now farmland,” Giles explains.
“The runoff from the land in that catchment carries sediment into the Wairoa river and that ends up here. It then smothers the seagrass, which means that snapper and other fish can no longer feed on it. The pipi have pretty much all gone too because they prefer sandier areas.”
Mikaera adds, “The silt is the worst thing that’s happened to the Kaipara Harbour. I think it’s actually worse than toxic heavy metals in terms of overall environmental harm.”
The only things that grow there now are mangroves and invasive weeds like saltwater paspalum.
But Papatūānuku is a fighter and she is bringing new native wildlife into the Kaipara. We might not be able to get the number of snapper we had before but perhaps we will instead see a different ecosystem in its place.
“Interestingly, there are lots of little crabs that have come to live amongst the mangroves,” Mikaera points out. “There are lots of fish, like flounder, that feed on these crabs. And the mangroves themselves are also a great shelter for small, young fish to hide from bigger prey.”
The day ended with a poroporoaki (farewell) back at the marae, where the students told Mikaera and the rest of the kaitiaki what they enjoyed most about the day.
“I liked working as a team,” says Alicia, 13.
“I really liked today because I love being outdoors and the weather was awesome,” Rebekah says. “I definitely want to do this kind of work when I’m older; like as a geographer or biologist.”
For Destiny, 14, the mahi was particularly meaningful.
“This is my marae,” she says. “I live just up the road and I go down to the water a lot with my family.”
About the project
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This project is supported by the Unlocking Curious Minds contestable fund.