Farmers urged to protect their wetlands

Kaiwaiwai wetland, in the Wairarapa, constructed by dairy farmers Kaiwaiwai Dairies. Photo: RNZ
Kaiwaiwai wetland, in the Wairarapa, constructed by dairy farmers Kaiwaiwai Dairies. Photo: RNZ
Private landowners are being urged to protect freshwater wetlands in their own back yard.

Just over 90 percent of New Zealand's original wetlands have been lost, and a series of satellite images taken around the country by Forest and Bird show 13 percent of that total were damaged or destroyed between 2001 and 2015.

Forest and Bird and the National Wetland Trust want to make sure the message gets across: that it's important to save what's left, half of which is on private land, at risk of being cleared or drained.

In an interview with RNZ National, Forest and Bird's chief conservation advisor Kevin Hackwell said wetlands provide a vital environmental service and yet they are among our most degraded natural environments.

“The wetlands are the kidneys of the freshwater system. They slow the water down, the plants are pulling out nutrients, they are stopping sediment flow and are really important in keeping the water systems clean,” he says.

In times of drought and flood they are also vital water regulators, he says.

"They catch the water when it’s suddenly falling very heavily, they slow it down. Also, they are really important for drought. The wetlands store water make it flow slower, so they actually help mitigate a drought.”

Draining wetlands releases huge amounts of carbon into the atmosphere, but conversely, if maintained, they act as powerful carbon sequesters, he says.

Only now, he says, is there any concrete national guidance on wetland protection.

“This latest version [of the Act] they’re actually talking about there should be no further loss or degradation of natural wetlands, that the councils have to map and monitor the wetlands, they have to manage vegetation clearance near them.

“This is the first time into a national policy statement under resource management, we're going to get a national guidance to say all councils ‘come on guys, you've got to do your job.”

Wairarapa farmer Aidan Bichan, has protected and restored a few wetland sites including on his own dairy farm near Featherston. He told RNZ the one on his farm is protecting Wairarapa moana from nutrient run-off.

“Our farm is a catchment for Wairarapa moana and our wetland’s now taking out somewhere around 670 kilos of nitrate per year.

"So it’s protecting the lake and I agree entirely with the view that wetlands are the kidneys of the system and we need more of them.”

Certain principles govern what makes an effective wetland, he says.

“We needed it to be somewhere between 300 millimetres and 500 millimetres deep. So, it gave us the most efficient nitrogen removal. If it was deeper than that there was a risk it would start producing methane, but at this depth it's producing nitrogen gas, giving that off, and our wetland’s got half a hectare of water surface in total.”

The wetland has exceeded expectations of how much pollution it would process by about 400 percent, he says. And his neighbours are benefitting from it too.

“Our wetland probably only treats about 35 hectares of our farming operation, but it's treating water off well over 200 hectares.”

Bichan says there are four things that will help encourage more initiatives like his in the Wairarapa:

Make it easy to identify a wetland or potential wetland, policy that incentivises land owners to protect and re-establish wetlands, localised policy and good tools to educate farmers on how to go about it.

“We don't need chunky rules, the one-size-fits-all is a real disincentive for responsible landowners. 'Here’s a rule for the whole country' is bad policy and is bad for implementation.”

However, Hackwell says the work Bichen is doing shows just how important it is to have a national approach.

“We've got people like Aiden doing a brilliant job, I mean it's really impressive what he's doing and that work is great. And yet at the same time, some of his colleagues elsewhere in the country, even in the Wellington region, are busy draining natural wetlands.

“We've got this idea about clunky rules, yes, you don't want clunky rules, but no rules is what led to this disaster in the first place.

“We've got to have basic rules which say no, we don't degrade any more natural wetlands. And we work up from there.”

Add a Comment