Wetlands are dynamic systems that influence and are influenced by a complex range of environmental variables and undergo cycles of wetting and drying over temporal and spatial scales.
There is a lot of variability within and between individual wetlands. No two wetlands are the same and as a result, grouping wetlands into meaningful, discrete types can be challenging. The classification of wetlands may also depend on the region and landscape where the wetland is located.
The classification of wetlands into relevant types or groups that are more like each other than others is necessary and very useful for a variety of reasons, e.g. for management, monitoring and regulation.
does not fit all when dividing wetlands into types. Wetland types developed for one purpose will not necessarily be the same types as those developed for other purposes. A primary focus on biodiversity might provide types which recognise the importance for biodiversity. These would not be the types a farmer might need for assessing the grazing potential of wetlands.
Wetland and aquatic ecosystems classification processes should follow the steps below.
Purpose of classification
There are many reasons for classifying wetlands and other aquatic ecosystems. Before using an existing wetland classification or developing a new one the first step should be to think about why the classification is required, for example, to:
develop a synthesis of current understanding and knowledge of components, processes and drivers of each wetland type for managers
select and interpret appropriate indicators for monitoring purposes
identify regional areas which have similar broad patterns of natural distribution of aquatic biota
identify, track and compare changes in extent of different wetland types due to natural or anthropogenic pressures
assess representativeness and uniqueness for a range of purposes including conservation value assessment
facilitate communication about wetland ecology, values and management with technical and non-technical audiences and stakeholders
predict the presence or absence of species based on wetland type
form part of a basis of water allocation, regulation and catchment management to maintain wetland support areas and connectivity processes
When looking at the purpose of classification it also needs to be considered what characterisations or attributes would be most useful in describing the nature of a specific wetland and distinguishing them from others.
Scale of data capture and reporting
Attributes (or data features) can be collected at different scales (also referred to as levels) and the outputs can be displayed at different scales. The scale of data capture and resulting outputs needs to be formulated based on the original purpose of the classification. For example, you might want to know which wetland types are under-represented in the reserve system of Queensland. Although the scale of reporting is Queensland the data would need to be collected at a finer scale to ensure that all of the wetland types were included and assessed.
This diagram demonstrates just some of the scales used. By Queensland Wetlands Program 2010
Structure and levels used in the Interim Australian National Aquatic Ecosystems Classification Framework
Development and application of attributes
Traditionally classifications have focused on vegetation structure and communities, geomorphology, and hydro-geomorphology to describe wetland types. Combinations of these features are also used to establish typologies. Other methods use a combination of biotic data (e.g.) or morphological, hydrological and physico-chemical data (e.g.). Some classification schemes include bioregionalisations and incorporate geography and landscape characteristics; but sometimes classifications and bioregionalisations are separated.
Development of the method
Once the purpose, scale and attributes have been identified it is necessary to develop a method to apply the data to the spatial features and establish the criteria from which different types of wetlands can be derived. Applying all data in every possible combination could result in hundreds or thousands of possible types. The process of limiting the types by only combining certain attributes is determined by the method and ultimately driven by purpose. It is important when applying attributes to spatial data that all possible attributes are applied even if the final typology does not split based on that attribute. This will ensure that other typologies can be developed using the same attributes. A Queensland wetland classification method has been prepared for the development of conceptual models, wetland management profiles and mapping outputs. The Queensland Intertidal and Subtidal Ecosystem Classification Scheme extends the terrestrial and wetlands classification to include these other ecosystems.
Product—Communicating the results
Developing a classification scheme and applying it is only one part of the process. It is important that the outputs from the classification scheme are communicated effectively, both in terms of the method, attributes and derived products.
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^ Green, DL 1997, Wetland management technical manual: wetland classification, Department of Land and Water Conservation, NSW.
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