Better options for tussock grasslands
Better options for tussock grasslands
Continued grazing by sheep may be the best way to protect the iconic tussock grasslands of the South Island high country, according to conservation biologist, Associate Professor David Norton.
"The Crown is spending a small fortune buying tussock grassland from farmers and removing stock. But once the stock and farmers have gone, large areas will revert to bracken, scrub and wildling pines rather than remaining in tussock grassland.
"The outcome is unlikely to be positive from a conservation point of view and is certainly not what the public would expect."
Prof Norton, of Canterbury University School of Forestry, says the mid-altitude tussock grasslands of the South Island are seen by many New Zealanders as iconic examples of native ecosystems, when in fact they are the end result of centuries of human activity.
"Most of the land which is now in tussock was in forest or shrubland until moa-hunter fires destroyed it about 800 years ago. Fires and grazing have kept it that way ever since.
"There are few seed sources for native trees on most of this land. But weed seeds are plentiful.
"When stock are removed, some areas will naturally revert to their former glory. But over much larger areas introduced weeds, especially introduced trees and shrubs, will take over, unless the Crown is willing to embark on a very intensive and expensive ecological restoration programme.
"However, there is no evidence that this or any future government would contemplate doing this on the 1 million or more hectares involved."
He says the tenure review process, which enables high country leaseholders to freehold parts of their farms in return for giving up land with conservation values to the Crown, should itself be revised.
"More parks and reserves may sound ideal, but the reality is that putting land in the hands of the Crown does not necessarily result in a better environmental outcome.
“Simply changing the tenure of the land from leasehold to public conservation will not result in the conservation gains some claim it will.”
Professor Norton says ecosystems on high country farms are highly variable and are strongly influenced by climate, altitude and the history of human activity. Removing grazing will have a wide range of outcomes, many of which are highly undesirable from a conservation perspective.
He says the maintenance of existing tussock grasslands is often implied as a goal during tenure review, and is certainly what many people want to see happen. But there is also an increasing emphasis on the restoration of native woody ecosystems.
"Unfortunately this second outcome will be difficult to achieve without substantial input of resources by the Department of Conservation, resources the department is unlikely to have available.
"These two goals require very different methods of ecosystem management. In the absence of clear goals, it is not possible to determine what areas should be surrendered to the Crown or how they should be managed. It also means there is no objective basis for auditing the success of that management.
"The costs and benefits of different management options need to be considered during each tenure review negotiation if conservation values are to be protected."
Prof Norton says it might be better if high country farmers were allowed to freehold their farms, subject to a legally binding agreement or covenant designed to ensure agreed outcomes.
"Covenants have yet to be applied at whole-farm scale, but they offer an alternative to the simple land tenure splits we are getting now which aren't sensitive to the full range of either economic or biodiversity values."
To meet the constraints of a covenant, he says farmers would need to be willing to consider a wider range of values than traditional farming has involved. They would also have to regularly monitor the effects of their management, and would forego some traditional management practices like burning at some sites.
"But in return, they would gain freehold title and be able to undertake a wider range of economic activities than are permitted under their current leases," Prof Norton says.
"From the nation's point of view, covenants would capture the farmers' knowledge of their properties and build on an established ethic of stewardship. The presence of full-time 'managers' on remote properties also has major public safety and environmental protection benefits.
"Large areas of the high country environment
would be managed by landholders at their expense. Funds
which the Crown has set aside for the purchase and
management of this land could be channelled toward improved
management of the Crown's existing conservation estate."