Wellington’s land cover profile is characterised by:
- A predominance of grassland/other herbaceous vegetation cover (almost half of land area), of which most is exotic grassland.
- A substantial area of forest cover (about one third of land area), of which most is indigenous forest.
- Scrub/shrubland cover is predominantly comprised of indigenous scrub/shrubland.
- Urban area and cropping/horticulture comprise relatively small proportions of the regional land area overall.
The key changes in land cover between 1996 and 2018 in the Wellington region are:
- Grassland/other herbaceous vegetation (primarily exotic grassland) and exotic scrub/shrubland have decreased in area.
- Exotic forest, cropland, and urban area have increased in area.
- Exotic forest area increased the most (by about 21,500 ha), generally replacing grassland. Some of these grassland areas are steep and subject to erosion, mainly in the eastern Wairarapa. The largest areas planted in exotic forest were in eastern Wairarapa.
- In comparison, urban areas are small relative to non-urban land cover. Urban/built-up areas increased by about 1,300 ha.
The likely drivers and potential implications of the changes are:
- The increase in exotic forest area may have been driven by changes in government policy and the reduction in agricultural subsidies in the mid-1980s.
- The Emissions Trading Scheme and the government funded Afforestation Grant Scheme may have contributed in later years.
- The afforestation of hillslopes at risk of erosion (e.g., steep or with erosion prone soils, or both) under grassland cover can be beneficial to improving slope stability and to reduce soil erosion.
- The Greater Wellington Regional Council encouraged steep grassland afforestation through its Farm and Environment Plan programme during this period, particularly in eastern Wairarapa. There were 600 ha afforested in the Wellington region under the Afforestation Grant Scheme first round in 2009-2011. Under the WRECI programme from 2010-2012, there were 42 ha afforested and 223 ha planted in poplar and willows for soil conservation.
- The increase in urban area is likely to have been driven by population growth and increased demand for housing. The expansion of urban areas and lifestyle blocks onto surrounding rural land will reduce the land area available for primary production and, in some areas such as Otaki, Greytown, and Carterton, this could result in the loss of versatile soils and land from productive uses (e.g., commercial vegetable and orchard production).
- The increase in the area of 'orchards, vineyards or other perennial crops’ may be driven by growth in industries such as viticulture in the Wairarapa. The loss of orchards in Kapiti and Wairarapa areas is also 'hidden' within this category. The likely driver is urban and peri-urban/lifestyle block expansion and subdivision in these areas.
