Coastal habitats

  • Image, Coastal habitats.

    New Zealand has a diverse coastline that is 15,000km long. Reporting on our coastal seabed habitats helps us understand the state of the marine environment. We report on coastal seabed habitats in our territorial sea (up to the 12 nautical mile limit).

    We classified Coastal habitats as supporting information.

    Key findings

    Most of our coastal seabed habitats (covering 80 percent of the coastline) are in waters less than 200m deep.

    • Seventy-three percent of our coastal seabed, including the intertidal zone, is covered in mud (24 percent), sand (38 percent), or gravel (11 percent).
    • Biogenic habitats (created by living organisms, such as mangroves or seagrass beds) and estuarine habitats are less prevalent (0.5 percent and 2.0 percent, respectively), but have an important and productive role.
    • Twenty-three different habitat types cover 98 percent of our coastal seabed.
    Note: The values for some categories are too small to display.

    Definition and methodology

    New Zealand’s coastline is extensive and highly variable. This means neighbouring environments are not necessarily similar. Areas relatively close to each other can have distinct habitats, and geographically remote areas can have similar ecosystems (habitats and species).

    The Department of Conservation and the then-Ministry of Fisheries (2011) mapped habitats within the territorial sea (12 nautical mile limit) around New Zealand’s coast. The following physical characteristics were used to define habitats:

    • depth: 0–30m (shallow), 30–200m (deep), 200–>1,000m (upper to lower slope)
    • exposure: exposed, high-current, moderate, sheltered, estuarine
    • substrate: biogenic habitats, mud, sand, gravel, reef, volcanic.

    Habitat types (such as exposed rocky shore and high-current shallow reef) are broad in scale and do not reflect finer-scale ecosystem processes.

    Estuaries are transition areas between river and marine environments. They are highly productive, with a large diversity of organisms and habitats, and are nurseries for several marine species.

    Biogenic habitats, such as mangroves, seagrass, or shellfish beds, are habitats formed by organisms. They have highly diverse communities and are vulnerable to damage. The reported extent of biogenic habitats is underestimated because not all relevant habitats were included in the original mapping, particularly in deeper and offshore waters. Important organism-based habitats, such as algal forests, were also not included.

    Data quality

     Topic Classification Relevance Accuracy
     Marine ecosystems and habitats Supporting information

     relevance-indirect
    Indirect

     accuracy-medium
    Medium

    See Data quality information for more detail.

    References

    Department of Conservation & Ministry of Fisheries (2011). Coastal marine habitats and marine protected areas in the New Zealand territorial sea: A broad scale gap analysis. Available from www.doc.govt.nz.

    Archived pages

    See Coastal habitats (archived October 2016). 

    Updated 27 October 2016

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