Need for region-specific erosion policy: Mana Taiao Tairāwhiti

This large landslide blocked Tiniroto Road for a week in early October last year.

A new study shows there is an urgent need for a bespoke erosion policy for Tairāwhiti, researchers here say.

It follows the release of Stats NZ’s latest study on highly erodible land and estimated long-term soil erosion environmental indicators. The study shows of all regions, Gisborne had the highest proportion of its land classified as highly erodible land (15 percent, 1280 km²) in 2022. Gisborne also had the second highest amount of eroded soil washed into waterways (36 million tonnes) in 2022 based on the model.

The Gisborne region also had the highest proportion of very likely hot spots for high landslide risk where sediment is washed into streams (47 percent).

As the latest data is to the end of 2022, it does not include the extreme weather events of cyclones Hale and Gabrielle, which occurred in 2023.

Tui Warmenhoven, spokesperson for Mana Taiao Tairāwhiti, a group lobbying for sustainable land use in the region, says the report supports the growing consensus that land use in Tairāwhiti needs to urgently change.

“With 2023 rainfall twice the volume of 2022 and three times the average, we know the landslide risk and soil loss will have been even higher than the data in this report” said Ms Warmenhoven.

Mana Taiao Tairāwhiti believes the report supports the case being made to central government that the region is unique and needs a bespoke policy response.

“We are still waiting on commitments from the new Government in response to the land use inquiry completed nearly a year ago,” said Ms Warmenhoven.

“But one of the key issues for the region is that rural property values are based on unsustainable land uses like pasture and pine on erosion-prone slopes, posing both a financial and political challenge. Legal constraints coming on such practices will depreciate land values unless alternative income streams are quickly established or landowners compensated for a portion of the opportunity cost in retiring the

land.”

Mana Taiao Tairāwhiti acknowledges that transitioning from pastoral farming and pine plantations to indigenous reforestation can also affect local employment and community cohesion if the transition is not well supported from both public and private investment.

Nationally, 60 percent of Aotearoa New Zealand’s highly erodible land was in the North Island in 2022, according to the Stats NZ data.

This is despite the North Island comprising only 43 percent of New Zealand’s total land area.

“New Zealand experiences high levels of soil erosion due to steep terrain, high rainfall, and earthquakes,” environment and agricultural statistics senior manager Stuart Jones said.