Classification and Typology

Photo: Kakadu - Lana Haydon

Wetland Classification and Typology

Wetlands are inherently 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. Like most natural systems, no two wetlands are the same and as a result, distinguishing wetlands into meaningful, discrete types can be challenging. Nonetheless, the characterisation of wetlands into ecologically relevant groups that are more like each other than others, and that share similar ecological and physical drivers, can still be very useful and has been an important component of the Queensland Wetlands Program.

Recently there has been agreement at an Australian national level to accept a wetland characterisation based on broad wetland ecosystems (Cowardin et al., 1979) as follows (clickable links to relevent typologies):

Reservoirs (including water storage areas, excavations, wastewater ponds, irrigation channels, rice fields and canals) and subterranean (inland subterranean wetlands) have also been identified as wetland types.

Mangrove Photo: Cathy Ellis

Estuarine wetlands are those with oceanic water sometimes diluted with freshwater run-off from the land.

Cape Bedford Photo: Nick Cuff

Marine wetlands include the area of ocean from the coastline or estuary, extending to the jurisdictional limits of Queensland waters (3 nautical mile limit). This definition differs from that in Ramsar, as it includes waters deeper than 6m below the lowest astronomical tide.

Chinchilla Weir Photo: Cathy Ellis

Lacustrine wetlands are large, open, water-dominated systems (for example, lakes) larger than 8ha. This definition also applies to modified systems (for example, dams), which are similar to lacustrine systems (for example, deep, standing or slow-moving waters).

100 Mile Swamp Photo: Cathy Ellis

Palustrine wetlands are primarily vegetated non-channel environments of less than 8 hectares. They include billabongs, swamps, bogs, springs, soaks etc, and have more than 30% emergent vegetation.

Einasleigh River Photo: Cathy Ellis

Riverine wetlands are all wetlands and deepwater habitats within a channel. The channels are naturally or artificially created, periodically or continuously contain moving water, or connecting two bodies of standing water.

Photo: Moya Tomlinson

Subterranean wetlands are wetlands occurring below the surface of the ground and that are fed by groundwater i.e. caves and aquifers. These wetlands provide water to groundwater dependent ecosystems.

General Wetland Classification Systems

Many wetland classification systems and typologies have been developed over the past few decades, signifying both the difficulty in creating a definitive system and the potential for different frameworks to be necessary for different purposes and scales. Reasons for the identification of wetland types can vary, from representativeness or uniqueness assessments within an area, to the identification of different monitoring needs, and for a range of other management purposes. Regardless of their specific purpose, most wetland characterisations are based on describing attributes that can be measured and which, when combined, help to define the nature of a specific wetland and distinguish it from others.

The following table provides links to the main wetland classification systems in use within Australia and New Zealand.

Table 1: Wetland classification systems
Classification	Details
Ramsar	42 sub-types identified under three major headings: marine and coastal zone wetlands, inland wetlands, and human-made wetlands.
Directory of Important Wetlands	42 sub-types identified under three major headings: marine and coastal zone wetlands, inland wetlands, and human-made wetlands.
Cowardin et al., (1979) (North America)	5 wetland types: marine, estuarine, riverine, lacustrine and palustrine. 56 wetland classes. Modifiers: water regime, substrate, vegetation.
Hydrogeomorphic (HGM (Brinson 1993)) (North America)	1 wetland type: palustrine. Modifiers: geomorphic setting, water source and transport, hydrodynamics.
New Zealand Framework (Johnson and Gerbeaux 2004)	9 wetland types: marine, estuarine, riverine, lacustrine, palustrine, inland salt, plutonic (i.e. karst), geothermal and nival (i.e. alpine). Modifiers: water regime, vegetation structure, vegetation, substrate.
Blackman (1992) (Queensland) (based on Cowardin)	5 wetland types: marine, estuarine, riverine, lacustrine and palustrine. Modifiers: water regime, substrate, vegetation.
Wetland International – Oceania (Queensland’s south-western wetlands) (Jaensch 1999)	3 wetland types: riverine, lacustrine, palustrine. 20 sub-types. Modifiers: salinity (fresh and saline), dominant vegetation.
Kingsford and Porter 1999 (Paroo River, Qld)	7 wetland categories. Modifiers: vegetation, geomorphology, salinity, hydrology.
Timms 1999 (Currawinya, Qld)	5 wetland categories. Modifiers: geomorphology, hydrology, water quality, water plants, invertebrates, birds.
Casanova 1999 (Paroo Rivers, Qld)	6 wetland categories. Modifiers: water regime, vegetation.
Timms and Boulton 2001 (Paroo River, Qld)	5 wetland types: marine, estuarine, riverine, lacustrine and palustrine. Modifiers: based on aquatic fauna (driving variables: salinity, turbidity, water regime).
Northern Territory (Duguid 2002)	71 wetland categories under the headings: basins (17 types), flats (4 types), channels (21 types), springs (18 types), subterranean (1 type) and artificial (10 types).
NSW (Green 1997)	14 wetland categories under the headings: coastal, tableland, inland. Modifiers: hydrology, vegetation.
WA (Hill et al., 1996)	13 wetland categories. Modifiers: salinity, vegetation.
Victorian Index of Wetland Condition (uses Corrick and Norman 1980)	2 wetland types: palustrine, lacustrine. 39 sub-categories. Modifiers: vegetation, hydrology, salinity.