Wetland conservation priority on South Canterbury dairy development

South Canterbury farmers Kevin and Karen O’Kane are protecting a native fish close to extinction in Canterbury while converting a dryland sheep and beef farm to dairying.

Their farm backs on to Horseshoe Lagoon, a coastal wetland north of Timaru with the only known population of giant kōkopu in Canterbury.

The O’Kanes and two neighbouring farmers have built fences, dealt with willows and planted native trees to protect the lagoon, helped by $16,280 of Immediate Steps funding from the Canterbury Water Management Strategy Orari-Opihi-Pareora Zone Committee, Timaru District Council, Mackenzie District Council, rūnanga and the community. The Department of Conservation manages weed control and allocated $3300 towards ring-barking cracked willows to their sapwood then treating with glyphosate.

The couple started milking 340 cows in August, two and a half years after buying the 100-hectare farm then installing irrigation pivots, building a cowshed and meeting resource consent effluent management requirements. They have also completed willow control agreed to by the previous owner, fenced off a spring and stream running into Horseshoe Lagoon and planted a surrounding 5-metre riparian strip in swamp-loving native plants including flax, ribbonwoods, small-leafed Coprosma propinqua and sedge, Carex secta.

Family, friends and their children were invited to a planting day last spring. For the next few weeks, pukeko did their best to rip out seedlings but were thwarted by tree guards. Old man macrocarpa were left along the stream to provide giant kōkopu with shade and cover until native plantings are tall enough to take their place.

“It’s no problem,” Mr O’Kane said of his conservation work. “Cattle could have got stuck in the swamp areas and it’s satisfying seeing these places improve.”

Inspiration also came from sharemilkers Andy Palmer and Sharon Collett, who farm nearby. The couple fenced a stream in the Orari catchment, built crossings for cows before this was required by either Fonterra or the proposed Land & Water Regional Plan, then planted natives with support from Environment Canterbury and Central South Island Fish & Game.

“I’ve seen them rewarded with abundant bird and fish life,” Mr O’Kane said.

Orari-Opihi-Pareora Zone Committee Chairman Dermott O’Sullivan said dairy conversions were often a good opportunity to protect and create natural habitats.

“These are usually small areas with little impact on the business of farming but can be important from the perspective of water quality and ecosystem protection,” he said.

Fencing out stock and riparian plantings helps prevent soil, nitrates, phosphorus and agricultural chemicals washing into waterways. These nutrients promote blue-green algae which deplete oxygen in water and can be toxic.

Department of Conservation biodiversity ranger Steve Harraway applauds the three farming families’ commitment to conservation at Horseshoe Lagoon. Thanks to their efforts, the wetland is fenced off for long-term protection with invasive willows under control and 2000m2 is planted in natives.

“When DOC monitored and tagged the kōkopu in 2003-05 they all showed an interest and were keen to do something to protect this habitat,” he said.

The once gravelly bottom of Horseshoe Lagoon started filling with silt and soil in the 1970s when the government encouraged land development with cheap loans. One big flood event did most of the damage as foothill development and intensification on the plains left soil exposed.

The lagoon also supports eels and waterfowl including bittern and scaup, all important resources for tangata whenua.

“Today’s efforts are helping bring it back to as natural a habitat as possible,” Mr Harraway said.

Environment Canterbury biodiversity team leader Jo Abbott said Horseshoe Lagoon landowners are helping fulfil the “Ki uta ki tai” - from the mountains to the sea - vision of the Canterbury Water Management Strategy, with help from Immediate Steps.

The Environment Canterbury Biodiversity Fund also helps pay for conservation, prioritising projects in areas where values are already high such as native bush and braided rivers. The Honda TreeFund supports community native planting projects.

“Together, these funds have so far awarded over $5 million to around 450 projects protecting Canterbury’s biodiversity and ecosystems,” Dr Abbott said.

Ecosystems at Wainono Lagoon near Timaru and Te Waihora/Lake Ellesmere, near Christchurch, are also being restored through a range of biodiversity programmes in partnership with Ngāi Tahu and the Ministry for the Environment.

For more information go to ecan.govt.nz/biodiversity or contact the Environment Canterbury biodiversity team via 0800 324 636.

Immediate Steps:

Is a $10-million Canterbury Water Management Strategy programme in its fifth and final year with a second phase possible
Has allocated over $3.8 million to 218 projects looking after waterways and native ecosystems around Canterbury, with almost $2.6 million still available
Is helping pay for 77 hectares of new native plantings and 157 kilometres of fencing
Canterbury ratepayers meet two thirds of project costs and recipients one third, mostly landowners, agencies and community conservation groups
Provides $500,000 in each of 10 Environment Canterbury water management zones plus $1.2 million towards regionally important braided rivers, Te Waihora/Lake Ellesmere and the Wainono Lagoon, near Timaru
Supports Canterbury Water Management Strategy targets including ecosystem health and biodiversity, recreation and kaitiakitanga (guardianship) of water

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