December 4th, 2024

North Island home to 60% of New Zealand's erodible land, Stats NZ data shows

The latest figures, accurate up to the end of 2022, build on findings from 2019, utilising higher resolution data to paint a clearer picture of the erosion landscape across New Zealand.

The data also pinpointed hot spots across New Zealand where landslide risk and sediment wash into streams are significantly higher compared to the national average.
The data also pinpointed hot spots across New Zealand where landslide risk and sediment wash into streams are significantly higher compared to the national average.

Data released by Statistics New Zealand (Stats NZ) on Wednesday reveals that 60% of New Zealand's highly erodible land is located in the North Island, despite the island making up only 43% of the country's total land area. This significant figure highlights the environmental challenges the North Island faces, including steep terrains, high rainfall, and seismic activities that contribute to soil erosion.

The big picture: The latest figures, accurate up to the end of 2022, build on findings from 2019, utilising higher resolution data to paint a clearer picture of the erosion landscape across New Zealand. Soil erosion remains a critical concern due to its impact on land productivity, water quality, natural landscapes, and infrastructure.

  • Zoom in: In collaboration with Manaaki Whenua – Landcare Research, Stats NZ has updated its environmental indicators to assess long-term soil erosion levels and identify land at risk of landslides, earthflow erosion, and gully erosion. This effort provides a detailed overview of the areas most affected by erosion and the types of erosion they face.

Details: Among all regions, Gisborne stands out with the highest proportion of its land, 15% (1,280 km²), classified as highly erodible in 2022. Furthermore, Gisborne recorded the second-highest volume of eroded soil washed into waterways, with 36 million tonnes in 2022, highlighting severe environmental impacts on land productivity and water quality.

  • Hot spots: The data also pinpointed hot spots across New Zealand where landslide risk and sediment wash into streams are significantly higher compared to the national average. Notably, 47% of the Gisborne region is considered a very likely hot spot for high landslide risk, underscoring the urgent need for targeted conservation and mitigation efforts.

The bottom line: Stats NZ's data underscores the urgent need for effective soil conservation strategies and careful infrastructure planning to mitigate soil erosion impacts, especially in the North Island and regions like Gisborne. Addressing these challenges is critical for preserving New Zealand's natural beauty and ensuring the sustainability of its agricultural productivity.