MfE reports on changes to NZ's landscapes - Expert
19 April 2018
The extent to which we have changed our natural landscapes is highlighted in the latest instalment of the Ministry for the Environment and Stats NZ's environmental reporting.
Our Lands 2018, released today, also indicates significant gaps in our knowledge about land use and the flow-on effects to soil.
The report and other materials are available on MfE's website.
Science Media Centre has asked experts to comment on the
report, please feel free to use these comments in your
reporting. Further comments will be added to our
Professor Rich McDowell, AgResearch principal scientist and Chief Scientist for the Our Land and Water national science challenge comments:
"While this report does provide a snapshot of the state of the land as far as impacts, it is important to note that it 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. 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."
No conflict of
Dr Ken Hughey, DOC’s Chief Science Advisor comments:
"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. It’s the gaps that I’m interested in. At DOC we have a robust data collection system, which has contributed to this report. Although we can provide data on biodiversity, ecosystems and land cover on public conservation land, the bigger picture for New Zealand is not quite so complete. 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.
No conflict of interest.