More data essential to determine land impacts


More and better data is needed to assess man’s impact on New Zealand, one of the authors of an influential environmental report insists


“The Our Land 2018 report just released by MfE and StatsNZ is a key document that will enable us to better understand where New Zealand stands in terms of challenges and pressures that our environment is facing,” says Motu Economic and Public Policy Research Fellow, David Fleming.

However, he notes that biodiversity in New Zealand is in danger as soils and water streams are increasingly being menaced by human activity.

“In order to better confront these challenges, the country needs to build more and better data sources on land use activity, resources use and condition.

“Without consistent national integrated data sources, it will be very hard to track future environmental conditions and the effects of policies or programs intended to reduce human impact.”

One “shocking” example is the shocking lack of rural waste data, Fleming claims.

“As pages 65-67 of the report explains, limited data on waste disposal impedes any assessment of the scale of the issue, let alone our ability to track any change.

“Better records and tracking of waste disposal is key to understand the risks that waterways, soil, air and towns face, especially given an expanding industry known for generating important volumes of non-natural waste such dairy (the report links to data estimating that dairy farms in Canterbury produce, on average, 9 tonnes of waste per year, excluding animal remains).”

In general, Fleming says the effort of the government in publishing such a report, and the strong self-criticism implied in its findings, should be applauded.

“If subsequent work supports the development of data systems and research that provide better insights on how land is being managed and impacts reduced, even better!”

Professor Rich McDowell, AgResearch principal scientist and Chief Scientist for the Our Land and Water National Science Challenge also has reservations about some aspects of the report.

He notes that the report does not provide insights into the trends in relation to phosphorus in the soil, and macroporosity of the soil – and how land use, and intensity of that use, contributes.

“Phosphorus in the soil is one measure, but there are other variables at play such as compaction of the soil, that will dictate whether there is phosphorus run-off into waterways to do damage.

“What we do know is that the data for water quality (in regard to phosphorus) and sediment concentrations indicate that far more sites are showing improvements now (2004-2013) than before (1994-2003).

“This is despite changes in land use, land use intensity and indications that phosphorus under dairying is enriched, and macroporosity of the soil is impaired.

“These improvements may be due to greater awareness, farmers being more proactive or policy changes.

Efforts include the isolation of critical source areas that contribute most phosphorus and sediment loss from farms or catchments, and targeting critical source areas with measures to mitigate these losses.”

The question is always whether these efforts are enough to meet community aspirations of water quality, McDowell says.

“This is why the Our Land and Water National Science Challenge (hosted by AgResearch) is supporting work examining land use suitability, and providing indicators on what a parcel of land can produce, the potential of these land parcels to lose contaminants, and the effect of these contaminants on water according to a water quality objective.

“This work will also be expanded to examine objectives for soil.”

“Our Land 2018 gives us a good idea of the state of New Zealand’s land and the pressures that affect it, while not shying away from highlighting the knowledge gaps that prevent it from being a thorough picture, adds DOC Chief Science Advisor, Dr Ken Hughey.

He says that while DOC can provide data on biodiversity, ecosystems and land cover on public conservation land, the bigger picture for New Zealand is not quite so complete and this issue needs attention.

“There is much biodiversity that needs to be protected outside public conservation land and that’s where we need more information. Habitat fragmentation and habitat quality need attention and we need to get information on data deficient species in those habitats. Wetlands continue to be of major concern and data shows ongoing decline. This is another matter that needs attention.

“The good news is that although a high percentage of our native species are in trouble, our data also shows that where we have intensive management and/or landscape-scale pest control, we can stabilise populations and even reverse declines.  Good examples include rowi, takahē and mōhua. They are no longer in decline after multiple pest control operations.

“We’re also working with central and local government, landowners, industry and communities to reduce the impacts of wilding conifers, a major threat to our ecosystems taking over natural landscapes, including rare ecosystems.

Wilding conifers occupy approximately 6% of New Zealand’s total land area – over 1.8 million ha – and were spreading at rate of 90,000 ha per year.

“Without the control work of DOC and our partners, wilding conifers would have invaded 20% (5.4 million ha) of New Zealand’s total land area,” Hughey claims.


The report and other materials are available on MfE’s website.