Active sand dune extent

  • Image, sand dune extent.

    Active sand dunes are distinct coastal habitats that sit between the land and marine domains. Characterised by their moving sands, they support a unique group of plants and animals. These plant and animal communities are threatened by human efforts to stabilise dunes for their own use.

    We classified Active sand dune extent as supporting information.

    Key findings

    In 2008, New Zealand’s active sand dunes had decreased 80.5 percent from their predicted pre-human extent (129,402ha to 25,208ha).

    • The first report on the area of active sand dunes, published in 1911, estimated that they covered more than 127,000ha (Cockayne, 1911).
    • Accurate mapping in the 1950s confirmed the original estimate, placing their extent at 129,402ha.
    • Active sand dunes probably changed little from the early to mid-1900s, after which time their estimated extent began to decline.
    Note: No data are available for the 1960s. The 1950s, 1970s, and 1980s extents were calculated from topographic maps and other historic sources. The 1990s extent was calculated from aerial photography. The 2008 extent was calculated using existing data and remote imagery.

    Definition and methodology

    Active sand dunes are dunelands that owe their physical, landscape, and ecological character to the ongoing or very recent movement of sand by wind. They are predominantly associated with coastal environments.

    The extent of active sand dunes was first estimated in 1911 (Cockayne, 1911). Active dunelands were mapped for the 1950s, 1970s, and 1980s (Hilton et al, 2000) from published topographic maps. In the 1990s, their extent was mapped from aerial photographs held by local authorities and the Department of Conservation. The 2008 extent of active dunelands was mapped from satellite imagery by Landcare Research for the Department of Conservation.

    Data quality

    We classified Active sand dune extent as supporting information.

    Relevance

    relevance-indirect This supporting information is an indirect measure of the ‘Impacts on biodiversity’ topic.

    Accuracy

    accuracy-high The accuracy of the data source is of high quality.

    See Data quality information for more detail.

    References

    Cockayne, L (1911). Report on the dune-areas of New Zealand, their geology, botany, and reclamation. Available from http://atojs.natlib.govt.nz.

    Hilton, M, Macauley, U, & Henderson, R (2000). Inventory of New Zealand’s active dunelands: Science for conservation 157. Available from www.doc.govt.nz.

     

    Published 21 October 2015

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