MOWs: How a community group rescued Waihī Harbour Wetland

Burning pampas in May 2015.

This is the first part of the story of how Maketū Ongatoro Wetland Society (MOWS), a small community group, rescued the Waihī Harbour Wetland from weed oblivion and made it one of the best sites for wetland birds in the central North Island. MOWS recently won the Sustainable Future Award at the TECT Community Awards.

I have been prompted to write this story following an article in Te Puke Times detailing how the Department of Conservation was trialling a new method of determining Australasian bittern (matuku) populations in the Maketū/Little Waihī area.

In late 2014, Ryan Standen, the land management officer at Bay of Plenty Regional Council, contacted me to ask if we were interested in taking on another project. The quick answer was "yes".

So, a few days later we met up with Mark Anderson, the DoC ranger with responsibility for the site.

Access to the western section of the reserve is through the gate at the end of Wharere Rd and then down the stopbank lined with mature flax. After 800m, we came to a pump house and a very impressive barrier of pampas. Ryan tried to penetrate this, but failed dismally.

From the pump house, we were able to drive east as far as the Pongakawa stream, which runs through the middle of the reserve. We then followed the Pongakawa down to where it flows into Waihī Harbour.

Everywhere was covered with gorse, pampas, blackberry and wattle trees, some very large.

It was, to put it mildly, an ecological mess.

The redeeming feature of the site was the saltmarsh, which, apart from a few small mangroves and a few patches of sea couch grass along the shoreline, was nearly pristine.

Some 25 years ago, an attempt was made to turn the southern part of this wetland into pasture, a causeway was laid between the Wharere and Pongakawa streams and a culvert with a flapgate put in to allow water to drain out, but not to flow back in. The project was a failure, the site was abandoned and the pampas, gorse, blackberry and wattle allowed to take over.

With DoC support and regional council funding, we set to work.

Removing the pampas from Waihi Harbour Wetland.

In January 2015, we hired Joe Pihama and his two diggers. Joe spent seven days clearing the site, mainly removing pampas, gorse and blackberry, but also some of the many large wattle trees.

One interesting find was the remains of four vehicles that had been dumped there; we buried two of them and used the other two to form the basis of a small causeway to enable us to get across the drain into the southern part of the wetland.

In early May, on the eve of the duck-hunting season, someone set fire to the bunds of dead pampas. They must have gone to some trouble because fires were lit at several points along the bunds, and the northern bund was fired a few days later.

We have no idea who did this, but my name was quickly tagged to it. I have no real idea why it was done, other than to upset the duck hunters, or to blacken my name or the reputation of MOWS. It succeeded in the first, but failed in the others.

Once the site was cleared, the first job was to grass the area. If we had not done this, the weeds would have taken over, but by grassing the area, you can easily mow it and have manageable tracks. Access is essential for any successful project.

After the grassing, we planted the first section of the burnt pampas bunds. These proved to be very fertile. We have since realised we planted too many plants, too close to the trail, and we now have to have annual pruning sessions to allow us to use the trails.

In years two and three we continued planting in the western side of the reserve, along the Wharere and Kaikokopu streams, but it was not until year four that we did some planting on the other side, along the Pongakawa Stream.

There is a lot more work to do there because we must first remove the remaining wattles, and then deal with the invasive grey willows and reed sweet grass Glyceria maxima, a disastrously invasive grass.

The reserve is divided in two by the Pongakawa Stream. In early 2016, the Pukehina Stream, which forms the southern boundary of the reserve, was dredged. The dredging left a bit of a mess, so we talked to DoC and the council, and managed to get funding to have Joe Pihama and his digger back.

When he finished, the stopbank was mainly bare dredgings with the odd flax, some bracken and Cyperus and a single cabbage tree.

The western part of the Waihi Harbour Wildlife Management Reserve.

Our strategy with this eastern section of the reserve has been to do no planting, but control the weeds, pampas, gorse, inkweed and broom. This has been successful because the natives are returning.

The lone cabbage tree now has at least a dozen offspring, flax are also multiplying along with giant rush, wiwi and bracken, which together are taking over and squeezing out the weeds. The beauty of this system has been that it has cost little - just the weed control. Nature does the rest.

Quite early on we realised this wetland was a special place with a number of native bird species, in particular the matuku or Australasian bitter, of which there are probably fewer than 1000 birds in New Zealand.

Also in evidence were fernbirds, and we were fairly sure we would find rails and crakes, but in those early days, it was very much clearing the weeds so that we could get a decent view of both the freshwater wetland and the saltmarsh, and work out how to improve the habitat for these important taonga species.

■ Julian Fitter is chairman of and has been involved in MOWS since its inception in 2008.