Insights into the environment

New Zealand is geologically and ecologically diverse and its landscapes and ecosystems are complex.

A new report on the state of the country’s land has highlighted the impact of urban sprawl, the loss of important wetlands and emerging problems associated with soil compaction.

The "Our land 2018" report, released by the Ministry for the Environment and Statistics New Zealand this week, confirms the need for more action to improve land management.

Environment Minister David Parker says he is particularly troubled by how much  urban growth is occurring in irreplaceable highly productive land. Even in a country as lucky as New Zealand there are only limited qualities of these high-class soils.

The report identifies New Zealand is losing some of its most productive land to houses. Agriculture is under pressure from the loss of highly productive and versatile land due to urbanisation.

In Otago, there is clear evidence of what was once productive farm land now covered by housing developments as land owners find it more profitable to sell houses than primary products.

There has been a 7% reduction in land used for agriculture, meaning land and soil is lost to urban subdivisions, forestry and lifestyle blocks. Mr Parker is taking steps to address issues such as the loss of prime market gardening land around Pukekohe, as Auckland expands, as well as the impact of lifestyle blocks on the most productive land.

He recognises the need to ensure there is enough land to build the houses people need while noting the need for protecting the most productive areas of the country.

Federated Farmers is disappointed with much of the report, saying the data is six years out of date. The report lacks significant data and admits this multiple times. One of the factors highlighted by scientists is the shocking lack of rural waste data. Better records and tracking of waste disposal is a key to understanding the risks waterways, soil, air and towns face — especially in an expanding industry known for generating important volumes of non-natural waste.

Even with a lack of data, there are some disturbing facts which cannot be ignored. Soils and  streams are increasingly being menaced by human activity.

Compacted soil is one such issue. Healthy soil is like a sponge, full of holes to absorb air and water. When it is compressed it cannot absorb water, making it more drought-prone. Nutrients are then more likely to run off into waterways.

The report finds New Zealand loses about 192 million tonnes of soil each year to erosion, of which 84 million is from pasture land. The high volume of soil being swept into the waterways is choking aquatic life.

The Government, farmers and others with an interest in land have a role to play in better managing erosion-prone land. Much of the response to the report comes from environmental agencies firmly opposed to farming. However, farmers are not the only ones with a stake in the environment.

The report also confirms the continued loss of New Zealand’s limited wetlands which contain some of the most precious biodiversity and filter contaminants from the land. More must be done to protect these.

The good news is although a high percentage of native species are in trouble, data also shows where there is intensive management and/or landscape-scale pest control, populations can be stabilised and declines reversed.

Mr Parker has taken note of the report, and its shortcomings. He understands the need to have balance in the environment and has asked officials to start work on a National Policy Statement for versatile land and high-class soils. His contribution is important.

The effort of the Government in publishing this report, and the strong self-criticism implied in its findings, should be applauded. Further reports of this character will be needed to get better insights into how New Zealand manages its land and resources.

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