Farms pose 'threat' to wildlife

Accelerating development of the Mackenzie Basin could turn it into a Canterbury Plains lookalike within 20 years, a top scientist warns.

Landcare research ecologist Susan Walker, of Dunedin, told The Press a "new wave" of rapid land-use change had hit the region over the past 10 to 15 years.

The latest efforts to increase irrigation in the basin for crops and dairying would have serious effects on its distinctive plant and animal life.

Walker told the Upper Waitaki River Catchment hearings into water use more damage had been done to Mackenzie Basin ecosystems than anywhere else in the country.

About 35,200 hectares of the basin's 301,000ha had been converted for urban, forestry, irrigation, oversowing and topdressing purposes since 1990.

"This recent conversion probably represents the most rapid rate of indigenous ecosystem loss and landscape transformation within any single ecological region in New Zealand in recent times."

She told The Press she did not want to be drawn on whether the latest applications should be approved for 16 new dairy farms with nearly 18,000 cows housed in cubicle stables for five-sixths of their lives.

Changes in the past 15 years had been greater than those from any other human activities.

"It [the Mackenzie Basin] could end up like the Canterbury Plains – it already looks like that south of Twizel. It would be a bad thing for native species – there's not many species left on the Canterbury Plains," she said.

The basin's extremes of drought, cold, heat and wind, combined with shallow, stony soils had created a "highly stressful environment" supporting distinctive plant and animal life.

Dairying had started becoming an issue for flora and fauna only in the past five to eight years.

"There's been a lot of intensification for sheep and beef as well. In the basin alone, there has been 35,000ha of loss of native grassland that would have supported native species, of which most is for cultivation or irrigation or oversowing and topdressing for crops and more intensive pastoral farming.

"These new applications are additional to that and they don't seem to note the effects on terrestrial flora and fauna. On a big scale you're losing a system that not only supports plants and animals but freshwater fish and a whole range of native birds that depend on normal water flows, low-nutrient groundwater and river flows."

Under threat were the habitats of several plants, beetles, moths, grasshoppers, lizards and spiders, and the northern end of the Mackenzie Basin.

"The southern end of the basin has had the major impacts so far – between Twizel and Omarama, it's almost unrecognisable now, Walker said.

Green Party co-leader Russel Norman said pressure on ecosystems was a big concern.

"Factory farming is obviously the worst of the worst, but it is the whole intensification right across the Mackenzie that is the problem, the loss of biodiversity."

Labour Christchurch Central MP and water spokesman Brendon Burns said the Tourism Industry Association had concerns about the proposals.

"The association stated that the Mackenzie Basin is enjoying spectacular growth in guest nights compared to the rest of New Zealand ... Decisions should not be made with an eye to short to medium-term economic gains."

- © Fairfax NZ News