Marine Environment Classification - MEC

The Marine Environment Classification (MEC) has been developed as a partnership project between the Ministry and NIWA with the support of the Ministry of Fisheries and the Department of Conservation. The MEC provides a general map that shows the variation in both the physical and biological characteristics of New Zealand's marine area within our Exclusive Economic Zone. The marine environments can be mapped to different levels of detail, ranging from two to more than 70 marine environment groups. The Marine Environment Classficiation (MEC) has been defined using multivariate clustering of several spatially explicit data layers that describe the physical environment. This produces a classification that is hierarchical, enabling the user to delineate environmental variation at different levels of detail and a range of associated spatial scales. A physically based classification was chosen because data were available or could be modelled and because environmental pattern is a reasonable surrogate for biological pattern, particularly at larger spatial scales. The Marine Environment Classification was developed at two levels of spatial resolution. First a broad scale classification was developed for the entire EEZ. This classification has a nominal spatial resolution of 1 km, allowing mapping at scales of 1:4,000,000 and above. A second classification was developed for the Hauraki Gulf region. This classification has a nominal spatial resolution of 200 m (i.e. consistent with a maximum map scale of 1:250,000). The purpose of this regional classification was to assess the feasibility of producing higher resolution inshore classifications relevant to the more intensive management issues that frequently occur there. Statistical tests determined that the Marine Environment Classification classes are biologically distinctive. Thus, the classifications provide managers with useful spatial frameworks for broad scale environmental and conservation management. However the full utility, and indeed limitations of the classifications will only become clear as the classifications are applied to management issues. At the conclusion of this four-year development project the steering group was satisfied that the Marine Environment Classification provides a useful broad-scale classification of biotic and physical patterns in New Zealand’s marine environments and supported its use as a spatial framework for analysis and management of marine conservation and resource management issues. It is important to recognise that a spatial framework is a tool to organise data, analyses and ideas and is only a component of the information that would be employed in any analysis. The steering group considered that the development of the Marine Environment Classification should now move into a phase where it is tested by application to management issues. Purpose: The purpose of this project was to create an environmental classification system covering New Zealand's EEZ and the Hauraki Gulf Region (at two different scales). This aimed to provide a spatial framework for structured and systematic management by subdividing the marine area into units having similar environmental and biological character. This provides a tool for a variety of applications, including: • mapping management units that are relatively homogenous with respect to certain ecosystem properties rather than administrative boundaries • transferring knowledge of processes and values to other areas on the basis of similarity • defining management units that will be subject to similar objectives, policies and methods • predicting the potential impacts of events and resource uses based on ecosystem susceptibility (e.g. the effects of marine invaders on certain habitat types and species) • identifying priorities for protection (e.g. which parts of the environment should be included in marine protected areas) • identifying areas within which certain activities should be closely managed or avoided (e.g. in what kinds of areas should trawling be prohibited) • structuring monitoring programmes to ensure representativeness of all environment types, and providing a context for reporting state of the environment information • identifying priorities for further research (e.g. to identify or confirm the whereabouts of certain habitat types about which baseline information is required).

Two levels of spatial resolution are available within the MEC. A broad scale classification covers the entire EEZ at a nominal spatial resolution of 1 km, whereas the finer scale classification of the Hauraki Gulf region has a nominal spatial resolution of 200 m.

All NZ. More detailed resolution Hauraki Gulf including waters below the mean high water line (but not including estuaries) and within a line drawn eastward from Bream Head (approximately 36 degrees South) to meet a line drawn from south to north and intersecting Cape Barrier on Great Barrier Island (approximately 176 degrees East).

All NZ

Varied.

The MEC has been published by MfE as a DVD that contains all the data and documentation needed to use the MEC in a Geographic Information System. An overview report describing the MEC is available as a PDF file (3.5Mb)

Ministry for the Environment (MfE) has distributed copies of the MEC to all levels of national and local government, as well as to government departments and agencies. If you work for one of those agencies, then you will have a copy; check with your IT department. Otherwise, copies of the DVD can be obtained from MfE by e-mailing [email protected].

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