Intensive farming is destroying native plants at the fastest rate since European colonisation, Landcare Research says.
The Green Party says the country is in "biodiversity crisis" and Labour has renewed its call for a halt to tenure review on the South Island's lakeside properties.
Landcare Research's 2009 annual report, presented to a parliamentary committee last month, said the drive for increased profitability from land had become "disconnected" from biodiversity impact.
"Analysis ... confirms that agricultural intensification over the past 10 years has led to the highest rate of native vegetation loss since European colonisation," the Crown research institute's report said.
However, the Government says biodiversity is an environmental priority and that Labour presided over nine of the 10 years in question.
Landcare ecologist Bill Lee said moves to intensive farming practices over the past decade had "dramatically" wiped out native plants and animals.
"The Canterbury Plains have probably suffered the highest level of biodiversity loss of any ecological region in New Zealand."
He said biodiversity losses included shrubs, herbs, lizards and large invertebrates.
Fish species had suffered from pollution and loss of habitat from water extraction.
Green Party MP Catherine Delahunty, who is on Parliament's education and science committee, which received Landcare's annual report, said the destruction was "appalling".
"The whole country is in a biodiversity crisis," she said.
Labour conservation spokesman David Parker said the Government was allowing high-country land to be turned into dairy farms.
The Press reported last month that as part of the tenure review process there are plans to transfer 31,000 hectares from Crown ownership to private hands on five high-country stations overlooking Lake Pukaki.
Parker said Labour had excluded 65 high-country properties from tenure review while it was in power. National reversed the policy last August. "Intensive agriculture in these places have effects that we ought to be worried about," Parker said.
Federated Farmers dairy chairman Lachlan McKenzie said farmers could better produce the food needed by the country and the world by producing more on the same amount of land.
"There's not a massive intensification in New Zealand," he said. "It's been happening since we climbed down out of the trees."
Environment Minister Nick Smith said biodiversity was one of the Government's highest environmental priorities, after climate change and freshwater management.
"The irony of Labour and the Greens criticising biodiversity loss from this report is that they were in government for nine of the last 10 years that it refers to," he said.
A national policy statement on biodiversity was being worked on, but it was a "longer-term piece of work", he said.
INTENSIVE FARMING RAVAGES GRASSLANDS
About 80,000 hectares of South Island grassland has been converted to intensive agriculture between 1990 and 2007-08, an unpublished University of Waikato PhD study shows.
The study, supervised by Landcare Research remote-sensing experts, used satellite imagery, photographs and field checks to estimate that 80,000ha hectares of a 4.3 million-hectare "eastern grassland zone" in the South Island had been converted.
The conversion rate increased from about 2500ha a year between 1990 and 2001 to about 4200ha a year between 2002 and 2008, the study said.
Canterbury has 103 plant species that are acutely or chronically threatened – nearly half of the country's total.
- The Press
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