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2.0. Classification systems and spatial frameworks

There are shades of gray when it comes to describing the characteristics of classification systems and spatial frameworks. It is however useful to differentiate them because this helps to clarify how the different systems and frameworks can be used.

2.1. Classification systems

These provide an objective basis for dividing the complexity of the environment into relatively homogeneous units with similar characteristics. These units may be repeated many times across the landscape/seascape, often in sites that are not contiguous.

Each homogeneous unit classification is specific to an environmental system or attribute. For example:

Classification systems are often hierarchical and provide ascending levels of generalization. A useful test is whether data can be meaningfully aggregated upwards.

Homogeneous unit classification systems are used for:

2.2. Spatial frameworks

Spatial frameworks reflect a combination of environmental attributes across landscapes/seascapes. This contrasts with classification systems that address specific attributes such as benthic habitats/communities. Spatial frameworks often operate at less detailed scales. They are sometimes known as bioregional or biogeographical frameworks.

Spatial frameworks can provide a spatial basis and context for environmental survey and monitoring information. Examples of spatial frameworks include:

2.3 The relationship between environmental classification systems and spatial frameworks

Many of the most powerful environmental distinctions occur at the local scale (for example the boundary between a rocky reef and a sand flat). Detecting and tracking changes for environmentally distinct areas at the local level requires the use of detailed levels of a classification system. Conversely tracking broad scale changes requires the use of a bioregional context (spatial framework) or more general levels of the classification system.

It is appropriate and necessary to de-couple:

For example data on wetland types could be collected using the UNEP-GRID New Zealand wetland classification. Information about New Zealand wetlands could be reported using the levels of choice from the UNEP-GRID classification along with ecological regions and districts (for areas above mean high water springs) and the coastal and marine ecological areas of New Zealand, and/or administrative boundaries.

Providing data is appropriately georeferenced it should be possible to report it using a variety of biogeographic and administrative spatial frameworks. In contrast once data has been collected using a chosen classification system, it can be difficult to change classification systems without compromising the integrity/usefulness of the earlier data.

2.4 Land Environments New Zealand

New Zealand Land Environments (developed by Landcare Research) identify similar terrestrial environments, at a variety of scales, based on climate and landform drivers. This new type of framework (reported in Froude and Beanland, 1999) has elements characteristic of both spatial frameworks and classification systems. New computer hardware and software technology has made it possible to use a range of environmental factors to define spatial framework boundaries with much greater precision than was possible in the past. This has reduced the amount of heterogeneity within the land environments compared to, for example, ecological districts when both are mapped at similar scales.

At the habitat scale each land environment still contains a great deal of heterogeneity and so habitat and biological community classifications are still necessary. Models can predict what should be present in a given environment based on climate and landform parameters. There can be a significant difference between what is present at a site and what is predicted for the land environment. Reasons for this include local site variation and the effects of disturbance (whether human induced or natural).