The precarious state of New Zealand
Thousands of species are threatened, rivers are unsafe for swimming, we’re losing productive land, and the climate is changing. Charlie Mitchell looks at New Zealand’s changing environment.
New Zealand’s environment is in a precarious state and facing an overwhelming number of threats, according to a sweeping government stocktake.
The major issues include thousands of species threatened or at risk of extinction, rivers unsafe for swimming, the loss of productive land due to urban expansion, and a warming climate likely to destabilise many parts of the environment.
The findings were detailed in Environment Aotearoa 2019, undertaken by the Ministry for the Environment (MFE) and Stats NZ. The agencies are required by law to produce such a report every three years.
It measured dozens of environmental issues, some of which used updated or newly released data.
It described an environment besieged in numerous ways, largely as a result of human actions.
The report showed that when it came to the environment’s overall health, ‘‘things are very bad,’’ said Forest & Bird’s chief executive, Kevin Hague.
‘‘We’ve spent too many years in denial about how our actions – from rampant dairy conversions to destructive sea bed trawling – are irreversibly harming our natural world,’’ he said.
‘‘As a nation, we need to make a bold plan to protect and restore nature now.’’
While it paints a grim picture in many respects, the report’s assessment of native ecosystems and the plants and animals they contain is particularly bleak.
Almost two-thirds of rare ecosystems were threatened by collapse, the report said, and thousands of individual species were either threatened or at-risk of extinction.
Those species include 90 per cent of all seabirds, 84 per cent of reptiles, 76 per cent of freshwater fish and 74 per cent of terrestrial birds.
‘‘Many of the habitats – land, freshwater, and marine – that our native species rely on have been reduced or damaged,’’ the report said.
‘‘Such large-scale changes can make some species particularly vulnerable to extinction and lead to the degradation of entire ecosystems.’’
While some species faced improving
prospects due to intensive conservation efforts, many more were sliding closer to extinction. In total, nearly 4000 species had a threat classification deeming them at risk.
In the past decade, 26 species had improved in conservation status, but 86 had declined.The decline was particularly biased towards plant species; Myrtle Rust, a damaging fungal disease, was alone responsible for 30 plant species moving closer to extinction.
At least 75 species are known to have become extinct since human arrival: 59 birds, three frogs, two reptiles, four insects, and seven plants. More were likely to join them.
Because only a small portion of New Zealand’s native species are documented – the nearly 11,000 species known to us are likely just 20 per cent of what exists – the true scale of the problem was unknown, and almost certainly a significant underestimate.
The consequence was a ‘‘biodiversity crisis’’ of unknown magnitude said Dr Ken Hughey, the Department of Conservation’s chief science advisor.
‘‘The lower-profile flora and fauna are an essential component of our biodiversity,’’ he said. ‘‘They’re the building blocks that make up our soils, provide food for birds and fish, and enrich habitats – but we don’t know the rate of loss because we don’t have a complete picture of what’s there.’’
One factor in biodiversity loss was the destruction of the habitat plants and animals live in, which had fundamentally transformed New Zealand’s environment.
The extent of native land cover had declined significantly, the report said, and continued to do so; As of 2012, New Zealand had crossed a threshold in which 51 per cent of the country’s land cover had been modified, either through exotic grasses or urbanisation.
There were now more exotic plant species than native ones, and stoats, possums and rats now cover 94 per cent of the country’s land area, virtually everywhere but the harshest environments.
Native forests once covered 80 per cent of New Zealand, but today they cover 26 per cent.
A related issue was the disappearance of productive land, often due to urban sprawl. Urban areas had expanded 10 per cent since 1996, particularly around Auckland and Waikato.
Many waterways continue to be polluted by human activities. Using an improved method of interpreting water quality trends, the report paints a more complete picture of the nation’s freshwater issues than others previously.
In particular, it found water quality in pastoral areas remained degraded, likely as a consequence of agricultural expansion. On average, rivers in pastoral areas had nearly 15 times as much E. coli, 10 times as much nitrogen, and more than three times as much phosphorus as a river in native land cover.
Between 2013 and 2017, 82 per cent of river length in pastoral areas was not suitable for swimming, based on a standard relating to the risk of contracting campylobacter, a waterborne illness. ‘‘Many studies at national, regional, and catchment scales show concentrations of [several pollutants] in rivers all increase as the area of farmland upstream increases,’’ the report said.
Urban water quality was similarly polluted, and in some cases, worse. It was due in part to pollution from heavy metals, which enter waterways through urban runoff.
The report noted, however, that less than one per cent of rivers by length were in urban areas, while nearly half were in pastoral areas.
‘‘The same national scale pattern has been reported for more than 20 years,’’ said Dr Scott Larned, Niwa’s chief freshwater scientist. ‘‘[It] indicates that the government’s current reforms of the way we manage our freshwaters needs to be bold if they are to meet New Zealanders’ expectations for healthy and swimmable waters.’’
The usage of water was also examined, but like several other issues, frustrated by a lack of data. New Zealand’s water take per person is more than 2 million litres per year, the second highest in the OECD and nearly triple the average.
There is no data for how much water is actually used each year. The amount consented for use shows that more than 5 trillion litres of water is allocated to irrigation, around two-thirds of all water used nationally.
It is the consequence of a significant increase in the irrigated land area in
recent times: Irrigated land almost doubled between 2002 and 2017, from 384,000ha to 747,000ha. Much of that conversion took place in Canterbury.
There were shortages in data relating to oceans, too. What was clear, however, was the effect fishing methods were having on the marine environment.
New Zealand’s total marine catch had increased more than 20-fold over half a century, and larger ships using more aggressive methods were disrupting the sea-floor through trawling.
Bycatch (unintentional fishing) of threatened species was a particular problem, the report said: The majority of dead Hector’s and Maui’s dolphins in which a cause of death was determined had been the result of bycatch.
Thousands of seabirds, too, are likely killed each year as a consequence of fishing activity. New Zealand is a global hotspot for seabird life, and nearly all species are threatened.
The report noted, however, that the impact of fishing on deep sea marine ecosystems was not well understood. There were also knowledge gaps in regards to plastic pollution and the effect of sediment from rivers entering the ocean.
Sitting above all the issues was climate change, which was expected to have an effect on virtually all parts of the environment, the report said.
The warming climate was already showing up in the data, from melting glaciers, to more severe floods, to an increase in wasp numbers in some areas. ‘‘As an island nation with a large marine zone, long coastline, and an economy based mainly on primary production and international tourism, we are vulnerable to the impacts of climate change’’ the report said.
The average annual temperature is the warmest it has been in 10,000 years; Four of the past six years have ranked among the warmest on record.
The report noted, in particular, New Zealand’s high rate of per person emissions, which was above the average of industrialised nations.
Since 1977, New Zealand’s glaciers are estimated to have lost around one quarter of their ice – a volume of ice loss that could fill Wellington harbour 12 times, the report said.
Climate change had showed up in smaller ways, too. In Taranaki, the range of two we¯ ta¯ species shifted, which was attributed to climate changes.
The report will be presented to policy makers to inform their decision making.
‘‘We’ve spent too many years in denial about how our actions – from rampant dairy conversions to destructive sea bed trawling – are irreversibly harming our natural world.’’ Kevin Hague, Forest & Bird’s chief executive