Land Cover

Manawatū-Whanganui is characterised by sweeping plains and New Zealand’s largest area of hill country and steepland, mostly in pasture but also including indigenous and exotic forest. Stretching from Ruapehu in the north to Horowhenua in the south, and from the east to west coasts, the 2.2 million hectare area also includes tussock grassland, indigenous and exotic scrub, crop and vegetable production, natural bare areas, water bodies, and urban areas. Between 1996 and 2018, exotic grassland and scrub/shrubland decreased in area and exotic forest, indigenous forest, and cropland increased in area.

Manawatū-Whanganui’s land cover profile is characterised by:

  • A predominance of grassland/other herbaceous vegetation cover (more than half of land area), of which most is exotic grassland.
  • A substantial area of forest cover (almost one third of land area), of which most is indigenous forest.
  • Scrub/shrubland cover is predominantly comprised of mānuka, kanuka, and sub-alpine shrubland.
  • Urban area and cropping/horticulture together comprise only 2% of the regional land area overall.

 

The key changes in land cover between 1996 and 2012 in the Manawatu-Whanganui region are:

  • Exotic forest has increased in area from 6% of the region in 1996 to 7% in 2018, mostly at the expense of hill country pasture. The area of indigenous forest cover has also increased.
  • The area of horticulture and cropland has increased, and the area of exotic and indigenous scrub has decreased.

 

The likely drivers and potential implications of the changes are:

  • Most of the afforestation occurred from 1996 to 2001, during a period of relatively high log prices. This is expected to reduce hillslope erosion on farms and reduce sediment, nutrients, and bacteria entering the region’s waterways. Since 2001, afforestation has occurred at a slower rate.  From 2008 to 2018, afforestation has been maintained by  funding from the Ministry for Primary Industries and by Horizons' Sustainable Land Use Initiative (SLUI).  In contrast, the national trend between 2008 to 2018 has been one of deforestation.
  • The area of cropland increased, particularly in areas with good soil quality around Ohakune and from Whanganui to Levin. Much of this increase was in vegetable, cereal, or feed crops. This increase was mainly from 1996 to 2008, with the rate of increase slowing slightly between 2001 to 2008 and ceasing between 2008 to 2018.  Soil cultivation can result in increased losses of soil carbon, sediment, and nutrients, and degradation of soil structure over time.
  • The decrease in the area of indigenous scrub/shrubland (mostly mānuka/kanuka) may in future be balanced by increased planting of mānuka for honey production.
  • A small increase in urban area was most noticeable around Palmerston North.

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