Classification of natural inland, coastal, and anthropogenic wetlands - a proposal to the Ramsar Bureau for global application

C A Semeniuk & V Semeniuk Wetlands Research Association (Inc) Perth, Western Australia

______This document is presented to the Ramsar Bureau Workshop STRP July 2004 as a DRAFT document. While the text and illustrations are largely complete, the referencing is not fully complete, and the text still needs some citations to be added. However, rather than retain the document until finalised and polished, it is submitted as a draft for use and discussion by Workshop Participants prior to the scheduled workshop.

July 2004

Table of contents

1.0 Introduction and Philosophy of Approach 1 2.0 Definition of a wetland 6 3.0 Boundaries of wetlands 17 4.0 Review/discussion of wetland classification schemes, and case studies, illustrating 24 difficulties with current wetland classifications 5.0 A proposed hierarchical/scalar classification for natural inland wetlands 40 6.0 A proposed classification for open coastal, embayed coastal, deltaic and estuarine 61 wetlands 7.0 A proposed classification for artificial, alienated, modified, and managed 83 anthropogenic wetlands 8.0 References 92

Illustrations are attached at the end of the text, and are numbered according to the Section of text to which they belong. 1.0 Introduction and philosophy of approach

This document comprises a series of papers (or Sections) on the theme of wetland classification, undertaken with a view to developing a standardised approach to classification. The various Sections provide material for discussion on the following: wetland definition; wetland boundaries; review of wetland classifications incorporating classification criteria and case studies; the proposed classification for inland, coastal, deltaic, estuarine and anthropogenic wetlands; and finally a dichotomous key to classify wetlands.

To date, many wetland classifications have been devised within the framework of a given region, using local parameters to determine the scope, and often using local, historical or cultural terms as reference. A shift in attention in classifications from scientific inquiry and/or traditional pragmatism to politico-socio-management, combined with the practical difficulties in transferring of classification schemes from one physiographic/climatic region to another, or the correlation from one scheme to another, has created a renewed call for a wetland classification with greater unification, precision, and wider applicability. Examples of theoretical problems which have encumbered wetland classifications to date are: 1. assumptions underlying selection of criteria; 2. internal inconsistency in the use of criteria; 3. an inability to encompass all wetland types using the currently accepted criteria; 4. see- sawing arguments about the inclusion or exclusion of coastal wetlands; and 5. the failure of criteria to address climatically induced effects on wetland hydrological functions. To make the shift from local to global wetland classification, not only do such intransigent problems need to be re-examined, but new concepts which can be used to structure classification models need to be introduced.

In this document we are not criticising nor intending to overthrow local classification schemes (see Semeniuk & Semeniuk 1997), because generally they have been designed or have evolved to satisfy a specific objective or function, and often have grown out of a particular locality where they serve as a useful tool. The classification of wetlands by the indigenous peoples of the Great Sandy Desert in northwestern Australia illustrates this point well: the classification is practical, and has allowed these peoples to classify water in a way that mirrors its availability for their survival. While not conforming in all aspects to natural boundaries (e.g., a term like “jila”, meaning “living waters” encompasses lakes, seepage springs and any readily accessible shallow groundwater), their classification has the implicit objective of keeping the inhabitants alive in a hostile environment. Rather, our intention is to provide/construct a wetland classification that can be used globally for purposes of inventory, conservation, and nomenclature, and through the understanding of the terms proposed, provide some measure of description. The proposed classification can stand side by side with local classification developed in any given region and be used in conjunction with classifications designed for other purposes (e.g., vegetation, soils, or aquatic biota).

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In this study we are recommending a sea-change in regards to the approach in classifying wetlands - one that will assist in identifying more wetlands than are currently captured by any classification scheme, as well as place classification on a more robust and systematic footing. The foundations of the proposed approach are: 1. that land and water are the foundations of wetlands and need to be addressed at a primary level in any classification; 2. that scale needs to be incorporated in any classification; 3. that natural regions create the variation in wetlands, and hence wetlands reflect their natural regional setting, and so at some level wetland classification needs to reflect this aspect; and 4. that once classification is designed that has core or foundational units, then through the systematic application of scalar, physical, chemical, and biological descriptors, virtually any wetland can be classified.

However, while we might be intimating that what is proposed in this document by way of classification is a new approach, readers familiar with the literature on classifications will note a degree of overlap with other systems. This is to be expected, in that the basic raw material of wetlands, i.e., the land, the water, its salinity, the wetland substrates, and the resulting opportunistic, obligate or facultative biota, is the same for all classifications. Each classification simply focuses on some particular set of attributes of the available raw material, or rearranges their order of their importance. Our particular bias is to focus on land and water as primary determinants in the development of wetlands, and we proffer the approach suggested in this document as scientists who have come from the development of the philosophy of classification and nomenclature, as well as the disciplines of the earth sciences, hydrology, and ecology.

The question of why wetlands are classified is periodically raised at workshops by those who perceive that all natural phenomena are sites of spatial and temporal continua and feel that classification is arbitrary (Elliott & McLusky 2002). While the truth of this perspective cannot be denied for many natural systems, it is equally true that our sense and understanding of the natural world, and its interactive nature and complexity is fundamentally aided by the tools of classification. Common examples such as human gender differentiation, and spatial (height, width, and size) and temporal categories are universally used, almost without awareness. It is also true that many phenomena lend themselves to classification where there are natural disjunctions, discontinuous boundaries, or partitioning processes that create distinct and separate products. From atomic scale to megascale, the following suffice as examples of this aspect of the natural world: electromagnetic quanta, the partitioning of the elements, the crystallisation of chemical phases as distinct minerals, the existence of monospecific genera, the occurrence of truly obligate species in monospecific stands, and intra-planetary tectonic plates. In terms of nature reflecting continua, and products arising from partitioning, wetlands fall into both worlds, depending on the scale of observation, in that they reflect continua in landform, water, and processes, and reflect partitioning in other aspects of their nature.

Specifically, there are philosophical and pragmatic reasons for classifying wetlands which justify the effort and short comings of employing such a construct. The overriding concern amongst wetland scientists is the preservation of wetlands and the conservation of their inherent diversity, and classification is an essential tool in that

2 attempt to recognise and encompass wetland diversity. Our experience on the Swan Coastal Plain in southwestern Australia highlights this. In 1976, fired by a comment from a governmental development-oriented engineer seeking to turn a chain of wetlands into an interconnected recreational facility, stating that “we need to conserve only one lake as an example of a wetland, since wetlands are just wetlands”, we embarked on our wetland studies over nearly 30 years to show the vast diversity of wetlands types that could be methodically identified if a systematic approach was used in classification. We largely succeeded in raising the awareness of the conservation regulatory bodies, and the engineers, in Western Australia, to the fact that there are “different types of wetlands”, resulting in a large proportion of wetlands in that region being conserved.

Beginning with fundamental characteristics common to all wetlands, a hierarchical system can be developed to incorporate the many attributes of wetlands, their maintenance processes and functions. Beneficial physical or practical applications of wetland classification are numerous. They include, amongst others, social and geographical objectives such as ease of global scientific communication through the use of uniform concepts and terminology; inter-regional comparison and correlation; generation of global hypotheses; mapping; a framework for ecological studies; the systematic organisation of data which underpins design of land-use planning and resource management strategies; and the rationale for legal argument.

As to what is being classified, considerable debate has surrounded the primary problem on the basic definition of a wetland. This has come about partly through the broadening of scientific knowledge of wetlands, partly through recognition of transitional features in the landscape best associated with wetland systems, and partly through the demands of environmental laws for the term to include less ambiguous more quantifiable attributes. Discussion and history of the definitions of wetland may be found in the following articles and references therein (Pritchard 1967; Lefor & Kennard 1977; Fairbridge 1980; Coventry & Williams 1984; Semeniuk 1987; Ping et al 1992; Tiner 1999, Elliott & McLusky 2002).

A consensus currently exists that a wetland is an area of land in which the period of waterlogging or inundation is sufficient to develop physical and chemical responses in the soil or sediment. Further, the presence of such pedogenic/diagenetically altered soils, together with an abundance of water during the normal growing season, should induce colonisation by recognisable communities of biota adapted to or tolerant of such conditions. There are three components that underlie this concept: 1) the presence of water, 2) the presence of hydric soils, and 3) the presence of plants and/or animals adapted to waterlogged conditions for at least part of their cycle. We will explore these ideas later in Section 2 which is a review of the existing Ramsar definition of wetlands.

Our objectives in the construction of definitions and classification in this document are four-fold: 1. to develop a generalist definition to capture as many entities as possible within the concept embodied in the definition; 2. to construct classifications that are robust, that have solid foundations, and that can be built upon; 3. to ensure that the classification categories mirror the natural and anthropogenic world as closely as possiblek (in this context, human pragmatism and socio-political

3 perceptions are no bases for the foundations of classification); and 4. to select criteria and categories within the classification which are descriptive and not genetic.

We also will declare our specific prejudice in the debate on classification. Our approach is to identify natural groups utilising various criteria ordered in a given priority, to provide names for these natural groups (i.e., nomenclature), to design the names as single terms and not dual words, and to design names that mean something so that the original criteria can be reconstructed (i.e., the word or term can be deconstructed as to its etymology and roots).

A fundamental tenet we hold about the Earth is that is can be subdivided on its surface into two major realms: the land and the sea. In this context, we view the “land” as all continents surrounded or bordered by the sea. All wet environments on the land are “wet” lands, wetted by a variety of hydrological processes (Fig. 1.1). All wet environments along the margin of the land, wetted by their interface with the sea, are also “wet” lands, wetted by a variety of marine processes along that interface. In this context, we accord with the idea that there are continental wetlands (or inland wetlands), and coastal wetlands. Estuaries and deltas hold a special place in this perspective in that they are coastal wetlands that exhibit transition between freshwater land environments and marine environments (Fig. 1.2). As a result, we intend to separate natural wetlands into two major groups: 1. inland wetlands; and 2. coastal wetlands, that encompass open coastal wetlands, deltas, and estuarine wetlands (Fig. 1.2).

Marine systems are excluded from the notion of a wetland, but we note that oceans, seas, and other marine water bodies have been and can be classified according to size, setting, and relationship to the land. Large scale open oceans and seas can grade into intercontinental seas (e.g., the Mediterranean Sea), or be invaginated into the land mass at various scales (e.g., Gulf of California, the Adriatic Sea, the Baltic Sea, the Red Sea, and the Persian Gulf, amongst others), or with narrow connection, can be surrounded by a landmass (e.g., the Black Sea and Hudson Bay). On the other hand, large water bodies wholly within a continent, such as the Caspian Sea or the Aral Sea, regardless of their salinity, are intracontinental features, on a vast scale, though some may represent former marine embayments now trapped intracontinentally by continent building and accretion via intercontinental collision or ocean crust to continent crust upthrusting mediated by plate tectonics. We note these features of gradation, sizes, and various relationships of marine systems to the landmass, because we consider marine water bodies surrounded by a landmass to be still part of the sea if there is a connection, and conversely, large intracontinental water systems such as the Aral Sea to be megascale wetlands.

We now draw attention to our use of the word “scale”, its categories of subdivision, and its nomenclature in this document. We categorise natural and anthropogenic features into groups based on scales of observation. These scales of observation have systematically defined spatial limits, e.g., a square of 100 km x 100 km, down to a square of 1 m x 1 m. Accordingly, we may apply terms such as “large scale” or “megascale” to the large scale of observation, referring here to the size of the imaginary square that encompasses the feature observed, and terms such as “small scale,” “microscale,” or “leptoscale,” to the smaller scale of observation, with “mesoscale” applied to the middle range. While our use of the term accords with that

4 of Earth Scientists, geomorphologists, pedologists, and other scientists who refer to large features as being “large scale features” or “megascale features” and small features as being “small scale” or “fine scale features”, our use of the term “small scale” and “large scale” is contrary to its meaning in geographic mapping where a small scale map refers to a map of a large area (i.e., scale 1:1,000,000), and large scale map refers to a map of a small area (i.e., scale 1:2,000).

On a final note, mankind has had a profound effect on natural environments around the world, and has rendered many natural wetlands alien, anthropogenically maintained, or disturbed. Mankind also has created through earth moving, mining, damming, water discharge, a variety of artificially wet environments, or artificial wetlands. Many of these artificial wetlands today have important ecological, cultural, hydrological, and economic functions, such as the maintenence of populations of endemic and threatened flora and fauna communities, and of habitats for food production. These anthropogenic wet environments need to be incorporated into wetland classifications, and indeed they are also addressed in the classification in this document.

The structure of this document and content/rationale for the various Sections are outlined below:

2.0 Definition of a wetland review of definition of wetlands; the philosophy and terms underlying the definitions; review of the Ramsar definition; and proposed new definition of wetlands 3.0 Boundaries of wetlands review of the boundaries of wetlands and criteria for their recognition; exploration of various boundary situations; and proposed approach to delineation of boundaries 4.0 Review/discussion of wetland review of wetland classification schemes to classification schemes, and case studies, explore their criteria and workability, and illustrating difficulties with current review/discussion of case studies in some classifications s classic areas to determine the difficulties and workability of current wetland classifications 5.0 A proposed hierarchical/scalar description of proposed classification for classification for natural inland natural inland wetlands using a hierarchical wetlands scheme of landforms, water, and scale 6.0 A proposed classification forcoastal description of proposed classification for wetlands (open coastal, embayed coastal wetlands, including open coastal, coastal, estuarine, and deltaic wetlands) embayed coastal, estuarine, and deltaic wetlands 7.0 A proposed classification for description of proposed classification for artificial, alienated, modified and artificial, alienated, modified, and managed managed anthropogenic wetlands anthropogenic wetlands

5 2.0 Definition of a wetland

Though definitions of the term “wetland” have been provided by a number of authors (UNESCO 1971; Golet and Larson 1974; Lefor & Kennard 1977; Cowardin et al 1979; Zoltai and Pollet 1983; Coventry & Williams 1984), it has proven difficult to construct a formal and concise meaning in the midst of confusion and debate about what constitutes a “wetland” and in what location lies its boundary. Therefore, in the first section of this paper, the inconsistencies and contradictions in concepts and definitions of wetland are discussed, as a prelude to presenting a unifying approach to wetland definition, terminology, and classification. This paper is structured as follows:

1. the concept of a wetland 2. review of the current Ramsar definition of wetlands 3. proposed unified approach to the concept and definition of wetlands

2.1 The concept of a wetland Aspects of the concept of “wetland” are rather imprecise, and the term “wetland” carries with it an accumulation of diverse opinions and experience as will be outlined below.. This is the result of several factors. Firstly, although there is recognition that wetlands are habitats with unique properties of land and water, in practice, most are recognised by the occurrence of their hygrophytic vegetation. This pragmatic approach has been translated into a theoretical construct which then accords wetland vegetation a place in the definition of wet lands. No other landform are defined or classified according to the vegetation which grows upon them, e.g., mountains are classified as into their various types based on their shapes and underlying material, and dunes are classified on bases of geometry and relation to wind fields . The other factors that contribute to an imprecise concept an definition of wetlands include wetland water regimes; the range of landform types that may constitute “wetlands”, and the emphasis on underground water resulting from various perceptions of the word “land”.

2.1.1 Vegetation as a criterion Vegetation often is the determining factor in the recognition of a wetland. Though not explicit in the literature, there seems to be an implication that if there is no wetland vegetation, then there is no wetland, and this is a fundamental problem in the global perception of “what is a wetland”. It also results in the separation of permanently inundated basins into a “wetland” zone (i.e., with rooted vegetation), and an “aquatic” zone. In Western Australia, this perception is carried to an extreme when wetland vegetation is cleared. By virtue of the fact that wetlands are “landscapes with wetland vegetation,” such terrains cease to be wetlands when that vegetation is removed. Yet, even without the vegetation they still remain wet lands, and vehicles or people traversing these terrains will still bog in the soils. The practice of defining a wetland by vegetation also excludes several types of wet habitats, such as permanently waterlogged saline basins, seasonally inundated salinised groundwater basins, and seasonally inundated perched water basins.

6 The effect on vegetation of water depth and its presence above or below the land surface provides another example of conflict in precisely defining a wetland. For example, a shallow water filled relatively small basin on a floodplain, or a water- filled dune slack, or a permanently filled small basin (a pond) are viewed as wetlands, yet when basins become large and deep enough, a new term is used, i.e., lake, and the term “wetland” then is applied only to their seasonally or intermittently exposed shores (Fig. 2.4). In these larger and deeper basins, the land that is underwater is not viewed as wetland, the focus being on the water body, resulting in the system being compartmentalised, as noted above, into a “wetland” environment and an “aquatic” environment. Here, although not always explicit, the definition of wetlands is intimately linked to the presence of rooted hygrophilic vegetation. The exclusion of “deep water habitat” (Cowardin et al 1979) from wetlands underscores the fact that lower parts of deep waters are not within the photic zone. However, deep water habitats, while perhaps inundated by sufficient depth of water to exclude vegetation still have floors that are landscapes (Fig. 2.5), albeit inundated landscapes, and in principle are no different to the floors of shallow water (vegetation-free, or even vegetated) basins, except in regard to the issue of the photic zone. Essentially, then, the separation of wetlands from deep water habitats is one focused on the presence or absence of vegetation.

The contrasting emphasis and significance that should be placed on vegetation in the the definition of wetlands is exemplified by two schools of thought currently circulating, that of Cowardin et al (1979) which recognises wetlands largely as the hygrophytic vegetated terrain bordering deeper water habitats, which themselves are not considered to be wetlands; and that of Semeniuk (1987), Semeniuk & Semeniuk (1995) in which wetlands express themselves as part of a continuum of interaction between land and water, and wherein a wetland can contain zones of varying degrees of wetness. These are best compared diagrammatically (Fig. 2.1.). There are a number of assumptions and rationales underlying these two points of view, as discussed below.

In the first school, exemplified by Millar (1976), Cowardin et al (1979, 1995), and to some degree Malmer (1986), adjacent areas on the shore of a basin or channel are categorised as different wetland types on the basis of a particular criterion (most commonly physiognomic type of vegetation). At the continental and subcontinental scale, wetlands are viewed as lands transitional between terrestrial and aquatic environments (Cowardin et al 1979). The transitional unit referred to in this perspective is not actually a land unit (as stated), but rather a zone reflecting transitional hydroperiod and water levels. The hydroperiod and water levels of wetlands lie in between the aquatic and terrestrial environments of Cowardin et al. 1979). At the local site-specific scale, although the approach is the same, the criteria selected are not. In some cases, the hydroperiod is the distinguishing characteristic, e.g., permanent versus seasonal waterlogging, in other cases it is the type of vegetation, e.g., moss versus trees, the presence/absence of vegetation (wetland/lake), or the scale of the wetland (e.g., if open water is < 8 ha it is placed in the wetland category, if it is > 8 ha it is a deep water habitat). Common to this approach, regardless of criterion used, is the use of the sharp boundaries between various vegetation formations and that between vegetation and water. However, in reality, they are part of a natural gradient responding to slopes, soil patterns, and penetration of light. Also common to this approach is the implicit incorporation of

7 scale. Using an example from Cowardin et al (1979) which differentiates between “lake” and “wetland” on the criterion of presence/absence of vegetation: if an area which is unvegetated (pool, or bare soil), occurs within a “homogeneous” vegetation unit, its recognition and classification will depend on its size. Patches of non- vegetated water in the midst of emergent vegetation are not necessarily called “lakes”, but are termed “unconsolidated shores” (Fig. 2.2). Similarly, using the criterion of plant composition or source of water, the scale of an area which is vegetated by a different physiognomic plant community within a “homogeneous” vegetation unit will determine whether it is recognised as a different wetland type. Small patches of mounded Sphagnum moss in the midst of fens are not necessarily called bog because of their small size.

In the second school, at the continental and subcontinental scale, terrain that is permanently inundated aquatic environments such as “lakes” and “rivers” are hydric systems within the land masses. There is a continuum in the regime of water presence, from wholly and permanently inundated, through to periodically inundated and exposed, to waterlogged, and other types of wetlands. The wetlands are viewed to be hydric systems within the land masses representing various locations in this continuum of water regime. The occurrence of vegetation is not afforded a role as a fundamentally determining criterion. At the local site-specific scale, the wet lands (two words) are perceived to be lands that are wet and composed of two fundamental attributes, land and water. Therefore, attention is directed to, and concentrates on, the continuum of water in its depth and longevity. From the centre of a basin to its shore, there will be a gradient in wetness, creating (at one extreme) zones of permanently inundated surface to seasonally inundated surface to waterlogged surface, and (at the other) a relatively homogeneous unzoned seasonally waterlogged surface. The boundary of a wetland should encompass all the zones of wetness, i.e., all the zones that are “wet” lands (Fig. 2.3).

However, in the literature it is evident that the approach to wetland definition and classification, generally, to date, has not been of wetlands as wet landforms but of “ecology.” That is, what types of plants are present; what makes a plant grow where it does? What are the soil types, water types, and sources of water that define, determine, or maintain the vegetation, or result in its distribution? At a fundamental level, implicitly (though not stated explicity) it is also the inclusion or exclusion of the photic zone. If there is a need for a classification for wetland vegetation, then the classification should be ecological, but such classifications should not form the fundamental basis of the definition and classification of wet landscapes. Vegetation actually is a secondary, or even tertiary, outcome of more fundamental underlying determinants, i.e., the land and the water, and their interaction, both hydrologically and hydrochemically.

2.1.2 Water regimes and wetlands A variety of water regimes and hydroperiods result in the development of wetlands (Fig. 2.6). Where there is permanent, year-round, water-saturation of a given terrain there generally is no debate that the terrain would be viewed as a wetland. This also applies to seasonally water logged or inundated terrain. However, problems in the concept and definition of a wetland can arise where surface or shallow water tables are present on a intermittent basis. Two examples in arid regions serve to illustrate this point: short term shallow water tables resulting from rapid infiltration from

8 flooding on, say, a 10-20 year turnaround, and longer term inundation following 50- 100 year-turnaround floods. While there may be no evident change in vegetation or soils that develop in these environments, in the short term there may be aquatic invertebrate fauna, fish and frogs inhabiting the inundated and wet terrain, and an influx of opportunistic waterbirds feeding and breeding in the temporary wetland. Short cycles in climate in more humid settings, on, a circa 20 year turnaround, may also result in some wetlands being dry for 15 years and definitively wet for 5 years, providing difficulty in stating “what is a wetland”.

Problems of the concept and definiion of wetlands also can arise in regard to waterlogging, i.e., water-saturated land. The issue here is how much waterlogging is required for the terrain to be considered a wetland? Waterlogging can be discerned through direct observation, through extrapolation (using the position of the water table and the height of the zone of capillary rise above the water table), and quantified using a variety of methods. In the absence of quantitative data, a reliable indicator of waterlogging is the position of the water table relative to the ground surface (usually fixed at < 30 cm). Traditionally, though, soil moisture content has been used as a measure of soil saturation. This approach has steadily been refined and a method designed for distinguishing wet from saturated soils using measures of pore pressure, with a cut-off point at 1 kPa (Dudal 1992). More recently, with the interest in anoxia and anaerobic conditions, and based on the assumption that waterlogged soils are anaerobic, many techniques used to measure oxygen levels have been employed in the determination of waterlogging, e.g., measures of redox potential, free oxygen levels, or concentrations of specific products of anaerobic decomposition (methane, hydrogen, ammonia, hydrogen sulphide, amines, reduced forms of iron and manganese) (Ponnamperuma 1972, Gambrell & Patrick 1978, Neue 1985, Moore et al 1992).

2.1.3 Landscape types and wetlands Albeit a wetland is any terrain that is waterlogged or inundated for a large part of the year or the whole year, in regard to landscape types that may be considered as wetlands, a general opinion exists that the most common and important wetlands are flats and basins that comprise “bottom-lands.” Here, such terrains often are underlain by water saturated soils, such as gleys, or peat. In contrast, steep slopes or cliffs are not generally considered as wetlands even though there may be year-round seepage creating a water saturated surface inhabited by one or more of some hygrophilic assemblages of bacterial biofilms, mosses, algae, and perhaps angiosperms and ferns. Yet such land surfaces would be considered wetlands if they were flat.

Channels systems such as rivers, creeks, rivulets, and brooks provide further examples of wet systems which may or may not be viewed as wetlands. While some authors exclude rivers from wetlands, the only difference between rivers and lakes is that the former has channel-contained water generally flowing, while the latter has basin-contained water generally not flowing The issue becomes more complex for some river systems where channel-contained water flows during one part of the year after seasonal floods, and hence excluded from the definition of wetland by some, only later to become longitudinally segmented into a series of disconnected static water bodies for another part of the year, creating a chain of “lakes”, and hence included as wetlands by the same authors (Fig. 2.7).

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Even if a river is included as a type of wetland, there are questions as to where the definition of wetland ceases to apply in its catchment in relation to its steepness and to the longevity of water residing in the channel. A permanently flowing channel (a river) may grade upslope into a steeper, narrower channel with permanently flowing water or a moderately sloping permanently flowing channel, and further upslope into a steep, narrow, rocky channel seasonally flooding (colloquially termed “brooks”). While a majority of wetland researchers may accept a river as wetland, the opinion of “what is a wetland” becomes more divided the higher upslope the channels are taken. The notion of “wetland” begins to fail in the headwater regions of catchments, even though the characteristics of water regime and water longevity therein would render inclusion of a basin or “bottom-land” as wetlands.

Mound springs, i.e., self-emergent accumulations of minerals, formed as a mound from upwelling of groundwater, are another example of landscapes that provide ambiguity to the definition of wetlands. While the original spring seepage may have created a small clearly defined and unambiguous wetland patch, later, precipitation of minerals result in the growth and self-emergence of a mound, creating a larger body (perhaps 2-5 m high) that may have the following components: a small permanent pool at the crest of the mound (perhaps with rooted hygrophytic vegetation, aquatic vegetation, aquatic fauna), permanently wet seepage surfaces on various parts of the slopes of the mound (perhaps with biofilms, or mosses, or ferns), seasonally wet seepage surfaces on various parts of the slopes of the mound (also with biofilms, or mosses, or ferns), and generally dry slopes that are wetted only rarely or intermittently. The entire complex, formed by wetland processes may end up as a mound with a variety of water regimes (Fig. 2.8).

2.1.4 Underground water, and the various perceptions of the word “land” Application of the word “land” to the subsurface, can create an imprecise concept of what constitutes a wetland. Consider three examples (Fig. 2.9): 1. a river along its length having waters fully exposed, then partly occluded, or fully occluded (underground); 2. a cave “lake” system that eventually through doline collapse becomes fully exposed; and 3. groundwater. If a river is accepted to be a wetland, some land managers consider that partly and fully occluded portions of that river to be part of the same river, and hence a wetland. Thus, where a river goes underground for part of its course, the underground portion is a “wetland”. In a similar way, some land managers consider underground cave water bodies (or cave “lakes”) to be wetlands. Through doline collapse such water bodies may eventually become subaerially exposed and hence become true wetlands, and this factor appears to substantiate the idea that the original water body was simply a subterranean wetland. With groundwater, there is a view is that the term “land” can be extended to the subsurface (i.e., the subterranean), and the water saturated phreatic zone is considered by some as a “wetland”. In this case, virtually the entire subsurface of continents with groundwater would be seen to be subterranean “wetlands”. This view is corroborated by the occurrence of stygofauna, a specialised aquatic fauna that inhabits interstitial pores of groundwater aquifers, composed, say, of sand, or inhabits the micropores and mesopores of the water table or phreatic zone of karst regions. The problems in the three examples above relate to the imprecise use of the word “land”, resulting in the eroponeous allocation of wet environments to the realm of wetlands. We view “land” to be the surface expression of the Earth, and that

10 below the surface as the “subsurface”. This is equivalent to use of “terrain” and “subterrain” or “subterranean”. Underground water bodies, underground water-filled and flowing channelways, and groundwater are subterranean water systems, but are not wet “lands”, hence not “wetlands”.

2.1.5 What is landscape in accreting wetlands? To many scientists the concept of landscape is clear: it is the surface of the Earth. Landscape, however, is dynamic, and depending on the temporal scale, it can be rapidly to slowing eroding, or rapidly to slowly accreting, and in this context wetlands can be set in eroding landscapes (e.g., river channels) or accreting landscapes (e.g., basins). Given that wetlands are commonly occur as bottom-lands or topographic depressions (viz., basins, plains, vales and channels), they frequently are sites for accretion and, as such, accumulate sedimentary materials as exogenic sediments or as endogenic biogenic materials (Semeniuk & Semeniuk 2004).

Figure 2.11 addresses the issue of accretion of sediment, soil, or biogenic material in wetlands. The original topographic depression (basins, channels, vales), or the slope or hill top, without sedimentary accretion, is termed the “parent surface”, and its morphology prior to accretion is the parent wetland landscape. For topographic depressions, sediments, soils and biogenic materials accumulate, and the depressions begin to fill, generally up to the level of high water. The wetlands progress from thinly filled depressions grading to thickly filled depressions, and finally mounded deposits within the depression. Plains, slopes and hill-tops develop thinly to thickly accreted deposits as thin sheets or wedges.

For basins, channels and vales, even though filled with thin to thick sedimentary deposits, they remain mainly as topographic depressions. However, if the accretion continues vertically beyond the original high water level of the wetland, mounding of deposits can occur, and we term this as “self emergence”, forming a “self emergent wetland”, the new landscape being the mounded raised surface. If peat is the fill material, basins can fill to the point that they begin to self-emerge to form raised bogs. Similarly, channels and vales may accumulate peat, and accrete to the point of self-emergence to develop into raised bogs. Basins also may accumulate mineral precipitates, which through continuing crystallisation may form raised mineral mounds. On the other hand, plains with local artesian water source, may accumulate minerals, or diatom deposits, or peat to form carbonate mounds, diatomite mounds, sinter mounds, or pear mounds. If there is mineral-charged artesian upwelling or volcanic water upwelling, mounding of surfaces also can take place on plains, slopes and hill tops, otherwise accreted material forms just a thin sheet covering the parent surface topography.

The surface of the accreted deposit within or upon the parent surface thus forms the new landscape. In drier climate, where wetlands generally form as discrete, separate sites of accumulation, usually in lowland or bottom-lands, the overall pattern is one of isolated wetland deposits situated in regional landscape (Fig. 2.12). In wetter landscapes, the individual landscape elements of hill-tops, slopes, plains, channels, vales and basins accrete wetland material to form thinly to thickly accreted sheets and mounds - here contiguity of landscape elements will tend to result in a continuous sheet of accreted wetland material that thickens and thins and mounds

11 across and over the various topographic elements. However, in these latter wetter environments, the basic topographic parent setting is present as the template (or the substrate), and can be classified accordingly. In this context, raised bogs, and other self-emergent wetlands such as mound springs and peat mounds are not different types of wetlands to basins and channels, but rather the end members of an accretionary process wherein parent surfaces progressively have been filled or accreted to develop mounding (Fig. 2.12).

2.1.6 Other considerations in the concept of wetlands In addition to the problems outlined above, some of the variability in the concepts and definitions of “wetland” can be attributed to the fact that different perspectives exist on what is a primary criterion for separating wetlands (e.g., lentic versus lotic waters), and on the correctness of inclusion or exclusion of certain types of wet habitats, e.g., fresh versus saline waters. Some of the variability in the definition of wetlands also can be attributed to disagreement on the attributes of the land and water which separate wetlands and non-wetlands. Some authors include lands under tidal influence while others do not; some authors include wetlands in which the hydrological recharge and discharge mechanisms and water levels are anthropogenically controlled and managed, while others do not. These matters of diversity of opinion an perceptions are discussed below under the following sections: 1) lentic versus lotic waters, 2) freshwater versus saline water; 3) coastal versus inland wetlands, and 4) artificial versus natural wetlands.

The separation of wetlands into lotic (flowing water) and lentic (standing water) systems, as noted earlier, has most consistently been applied to distinguish channeled waters from basin waters (rivers from lakes), and for some authors forms the primary subdivision of water types. It also parallels ecological subdivision, as biota fundamentally respond to water dynamics, separating out into stream ecology and lacustrine ecology. The idea of water dynamics, however, is biased by a perceived difference in the surface water behaviour rather than being based on any scientific standard. This is apparent when an attempt is made to apply the terms in environments occurring between the extremes of the framework (i.e., simple rivers and simple lakes) to wetland groundwater systems in which there are separate water flows moving at widely disparate rates within the same aquifer (Winter 1976, 1978, Siegal 1983, Siegal et al 1995, Grootjans et al 1996, Reeve et al 2000): some of such flows could be classified as lotic but some are so slow that they are lentic. In addition, some flows may only be very short term, and a number of studies have demonstrated that wetland water flows can be seasonal, or that measurable flow can occur in only portion of a wetland as opposed to the whole (Cherkauer & Zager 1989, Doss 1993, Philips & Shedlock 1993, Winter & Rosenberry 1998, Zeeb & Hemond 1998, Mann & Wetzel 2000). As a consequence of these observations, the notion of lentic and lotic dynamics should be viewed as generalisations or as descriptors of hydrological flows for a defined period and zone within a wetland rather than part of the definition of wetlands.

There is an implication in some wetland classifications that saline systems are not included. This may be due to the fact that apart from coastal salt marshes and mangroves, and inland saline samphire and marsh systems, they often do not support wetland vegetation. The problem would become complicated, however, where

12 wetlands have salinity changing in response to wetter and drier conditions, i.e., they arepoikilohaline. Our argument is that if the presence of water, and its longevity, is sufficient to characterise a natural system as a wetland, then its being fresh or saline is merely a subdivision of this fundamental attribute. Effectively, salinity should not be used at a primary level to identify wetlands, and the distinction between fresh and saline wetlands should more correctly be a criterion for subdivision of water types and inventories.

There is a distinction between coastal wetlands and inland wetlands, and although they can be separated on their many differences in terms of their nature, properties, or essential processes, the fundamental ideas of water and land interacting to form a wet land still apply. This is true whether the wet land is a discrete inland feature, or land based fringe/margin of an oceanic basin, or in between the two.

The issue whether artificial wet environments are wetlands has been a matter for debate. Additionally, in regard to the question of recognising artificial wet environments or managed (formerly natural) wetlands as distinct from naturally functioning wetlands, it is clear that in very many places in the world, wetlands are regulated to some degree to comply with demands of multiple land uses and potential anthropological needs. This is not just a recent phenomenon either. For many centuries, competing land uses have resulted in the alteration of many natural wetland systems, and these modified wetlands, together with artificially created ones, are often the only remaining repositories of some ecological functions, or refuges for remnant populations, and serve as oases in a landscape increasingly bare with respect to wetland habitat. For this reason, a modern definition of wetlands must include the characteristics of such relic and rare wetland features and artficial ones in whatever form they are extant.

2.2 Review of the current Ramsar definition of wetlands The definition of wetland used by the Ramsar Convention (UNESCO 1971), presented follows, illustrates various strengths and weaknesses::

areas of marsh, fen and peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed 6 m.

Firstly, it is not wholly a product of systematic construction. The terms pertaining to hydroperiod and water salinity are systematic, but this is not true of the opening examples of wet habitats. For these habitats, terms denoting and deriving from a variety of characteristics have been used e.g., marsh (vegetation formation), fen (water origin and soil type), peatland (soil type and vegetation), and water (surface water).

Secondly, several terms used in the definition must themselves be defined. What is a marsh, fen, or peatland? Definitions of these terms vary according to author and practitioner. As a result, the terms marsh, fen and peatland are often used interchangeably where there is some overlap, or are applied to different types of wetlands (see Table below).

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Supra-generic term Wetland type Soil type Water source Peatland Bog peat ombrotrophic Peatland Fen peat minerotrophic Peatland Swamp peat minerotrophic Peatland Marsh peat minerotrophic Peatland Mound peat minerotrophic Mound spring mineral soil minerotrophic Swamp mineral soil minerotrophic Marsh Marsh mineral soil minerotrophic Marsh Marsh mineral soil tidal

Thirdly, the definition omits many natural wet habitats which are universally recognised as wetlands, e.g., forested swamps, meadows and damplands, Australian arid “salt lakes,” and “mound springs,” amongst others. While the definition itself appears to present a narrow view of what constitutes a wetland, the list of habitats recognised to be wetlands in various Proceedings and Handbooks produced by the Ramsar Convention is more comprehensive (Ramsar Convention Bureau 1998), even though many do not conform to the primary definition. A consequence of this latter factor is a legal one. As it currently stands, the limited Ramsar definition of a wetland, in Court of Law, by strict application of the wording, would eliminate many wet environments from being considered as wetlands. For example, the Western Australian Government has adopted the definition by the Ramsar Bureau, and ratified it into Environmental Law (ref). The consequence is that any astute lawyer working in the interests of a land developer or industrialist could argue that the “meadows”, diatomite filled swamps, carbonate-mud filled mires, forested swamps, mangrove swamps, and mound springs, amongst many others, that occur in an area where there is a legal conflict of interest in land use, are not considered to be wetlands by the wording of the Western Australian Government, nor by the International Standards provided in the definition by the Ramsar Bureau.

Fourthly, some aspects of the definition have led to questionable interpretation, e.g., “the areas of marine water, the depth of which at low tide does not exceed 6 m” as applied to coral reefs and seagrass meadows. Scott & Jones (1995) make a cogent point when they remind us that the Ramsar definition befits the view of wetlands as waterfowl habitat. This is a functional viewpoint, however, and it tends to emphasise the diversity of wetland types which accord with waterfowl requirements while ignoring wetland types in which other functions may be more important, such as higher and lower order biological functions, physical functions such as sediment deposition and hydrological re-cycling, chemical functions such as grain precipitation and sediment alteration, other ecological functions (such as primary production), conservation functions (such as providing residency for diverse biota, or rare and endangered biota). Overall, this approach results in the inclusion of some doubtful categories of wetlands and the exclusion of other more obvious candidates. When, in any way, the objective for defining wetlands detours from that of encompassing the diversity of wetland types, the resulting definition will be unsatisfying.

14 A current consensus, following Cowardin et al., (1979), with respect to the meaning of the term “wetland” is that it is an area of land in which the period of waterlogging or inundation is sufficient to develop physical and chemical responses in the soil or sediment. Further, the presence of such pedogenic/diagenetically altered soils, together with an abundance of water during the normal growing season, should induce colonisation by recognisable communities of biota adapted to or tolerant of such conditions. There are three components to identifying a wetland (Canadian National Wetlands Working Group 1979; Cowardin et al 1979; Semeniuk 1987, 1991; USDA Soil Conservation Service 1991, Tiner 1999): 1. the presence of water; 2. the presence of hydric soils, and 3. the presence of plants and/or animals adapted to waterlogged conditions for at least part of their cycle, although in many wetlands, e.g., deep lakes, rivers, estuaries, high tidal flats, hypersaline wetlands, intermittently or briefly seasonally waterlogged areas, only two of these conditions exist. These components are only subtlely reflected in the Ramsar definition.

2.3 Proposed unified approach to the concept and definition of wetlands Our intention is to place the definition of wetlands on a firm footing, one that is robust, that addresses the fundamentals of wetlands, and that can be applied to as many wetlands as possible. We argue that the “essence” of a wetland, i.e. the land and water components, should form the foundation of any definition, and in this context, we focus on the “land” and “water”, excluding specific features of vegetation and soil types in the definition, leaving these latter attributes to be encompassed by the implication of the variety of environmental conditions embodied in the definition.

Our concept of a wetland is broad, drawing on experiences in the humid regions of Northern Europe, the British Isles, Northern America, Australia, and southeast Asia, the Boreal regions of Northern Europe and Canada, the arid regions of southern Africa and Australia, the alpine regions of Europe, Himalayas, and southeastern Australia, spanning a wide range of geological, physiographic, and hydrological settings, and it is our intention to expand the concept of wetlands to include the rich variety of wet habitats on the Earth’s surface as occuring in the range of settings noted above. It is also our intention to shift the definition and focus on wetlands from a vegetation bias to a broader view that encompasses deep water habitats (or lakes), salt lakes, mound springs, and the numerous other wet environments on the Earth’s surface.

In doing so, we stress that the water component of the Earth’s surface and shallow subsurface interacts with a continuum of land surface or landscape, producing a variety of passively formed wetlands (such as water filled rocky basins), or actively accumulating or accreting surfaces (leading ultimately to self-emergent wetlands), and as such, a definition of wetlands should reflect this continuum and not have a cut-off point dictated by vegetation or the photic zone. Thus, we suggest that the definition of “wetland” be expanded to include all wet environments on the Earth’s land surface, be they permanently and deeply inundated, permanently and shallowly inundated, seasonally inundated, waterlogged, supporting hygrophilic vegetation or not, supporting biofilms, stromatolites, or any other form of hygrophilic biota, with waters that may be fresh, brackish, or salty, and with sediments and soils that range

15 from peats, to sandy gleys, to humic sands, to carbonate sediments, diatomites, spongolites, gypsites, and salt deposits.

In constructing, refining, or remoulding definitions of phenomena and or features, that may be mulitidimensional, multi-component, complex, and with internal gradations (of which wetlands provide a clear example), the terms and concepts should be left broad, or constructed to be as broad as possible to encompass a large range of possibilities, to allow for additions as they are found, and they should not be later constrained or restricted in their meaning. In this context, in addition to having a broad definition, it is also inadvisable to restrict any relative terms within the definition (Eaton 1961), i.e., terms dealing with environmental complexity should be left as broad as possible to leave the possibility to capture all forms of the phenomenon or feature.

The most robust definition of wetlands, and the one that best encapsulates the variability of natural inland and artificial inland wetlands (e.g., using existing diverse terminology from the literature: lakes, swamps, mires, moors, pans, fens, bogs, forested swamps, meadows, mineral mounds, mound springs, peat mounds, “salt lakes”, various types of fluvial channels and fluvial plains, palusplains, marsh, saline water bodies, amongst others), in our experience both Australia-wide and globally, is that developed by the Wetlands Advisory Committee (1977). It was developed on a foundation of variability of inland wetlands in Western Australia, and was the one adopted by C A Semeniuk (1987), and by the Water & Rivers Commission (Hill et al 1996). Here, wetlands are defined as “areas of seasonally, intermittently, or permanently waterlogged soils or inundated land, whether natural or artificial, fresh or saline”.

However, to capture coastal wetlands, and to address the broader idea that wetland basins are underlain by wetland sediments and/or wetland soils, or by rock or non- wetland materials, the definition proposed is as follows:

areas of permanently, seasonally, intermittently, or tidally waterlogged to inundated soils, sediments, or land, whether natural or artificial, fresh to saline.

This definition thus deals with “wet” lands, regardless of how they have become wet (via various inland hydrologic processes, or coastal marine processes), regardless of their vegetation cover, be it moss, heath, sedge, rush, meadows, forests, regardless of the soil, sediment, or substrate types that underlie them (be they in situ organically derived, or in situ precipitates, or water-transported materials, such as peat, humic soils, gypsum, carbonate precipitates, alluvium), and regardless of the extent of inundation, permanence of inundation and extent of waterlogging. As a definition of wetlands, in our experience globally and in Australia, it captures virtually all wetlands that have been documented to date.

16 3.0 Boundaries of wetlands

Locating a wetland boundary is especially important in the mapping of wetlands, conservation of wetlands, in determining boundaries between conflicting land uses, and in assessing land capability. Given that recognition of wetland habitat is based on its hydrology, hydric soils, hygrophilic vegetation and other hygrophilic biota, it should be a relatively simple matter to delineate their boundaries using these criteria. However, problems can arise in delineating wetland boundaries resulting from a number of situations, viz., the type of gradient and soils along the shore, the sedimentologic/geomorphic history of the wetland margin, the merging of multiple basins, the effects of wetland habitat alienation, and varying climatic conditions. Consequently, wetland boundaries may be simple or complex, sharp or diffuse, and temporally static or dynamic, and as such, they often are difficult to define and delineate. This paper deals with the boundaries of discrete inland wetlands such as basins and channels (with adjoining flats and slopes), wetlands with complex boundaries, natural fluctuations of wetland boundaries, and the boundaries of coastal wetlands, providing examples to explore various geomorphic and slope situations that generate these variations.

3.1 Boundary of discrete inland wetlands The wetland boundary in continental (inland) settings has been dealt with in the literature elsewhere. For instance, in the USA, Tiner (1999) discusses this issue in some detail, and suggests that the wetland boundary needs to determined by use of criteria of hydrology, pedology and vegetation (Fig. 3.1). Some authors argue that all three need to be used (cf. Sipple 1988; Tiner 1993), but others view that only one of the three need to be satisfied. Authors tend to agree that of the three, the hydrologic criterion is the least reliable and least stable for determining boundaries. Tiner (1999) also discusses that determination of a wetland boundary should be undertaken by experts (i.e., in applying criteria of hydrology, hydric soils, and vegetation to determine the boundary of a wetland, it would be necessary to engage a hydrologist, a soil scientist, or botanist).

Hydrology can be used to define the boundary of a wetland by direct observation of the water line, and if the terrain surrounding the water line is wetted by capillary rise, then by the use of moisture content. This procedure can be relatively simple for wetlands with steep shores, underlain by rock, but can become complicated for wetlands with low gradient shores or underlain by finer grained materials, especially where the hydrologic system translates upslope into waterlogged soils and moist soils. Questions here are what levels of moisture content should define the boundary (e.g., where is the boundary as wetlands grade into low-gradient drylands), and where is the boundary in wetlands with complex margins?

Criteria for what constitutes a hydric soil are provided by USDA Soil Conservation (1985, 1991), Cowardin et al (1979), the National Resources Conservation Service (1995), and Tiner (1999). In our experience, the following soils and sediments are indicative of hydric conditions: peat, peaty sand, richly humic sand, (bleached) white quartz sand, grey quartz sand (gley), ferricrete, carbonate mud, carbonate muddy sand, ostracode sand, diatomite, diatomaceous sand, spongolite, terrigenous clay, and muddy sand, and for evaporative minerals and other precipitates, silica, carbonate mud, gypsum, and halite.

17

Many authors also have dealt with the use of vegetation to determine wetland environments (Warming 1909; Weaver & Clements 1929; Daubenmire 1947; Sipple 1988: Tiner 1993, 1999), separating facultative species from obligate species, and for the situation in the USA, providing estimates of percentage contribution of these species to the wetland associations. Obligate vegetation species are clearly linked to wetland environments, some located specifically in the wettest part of the wetlands, others in the outer periphery, and others inhabiting the boundary condition between dryland and wetland. Recognition of wetland vegetation facilitates recognition of a wetland boundary and recognition of habitat specific vegetation allow for a more precise location of that boundary.

The boundaries of different wetlands are explored theoretically in six situations that satisfy the criteria of terrain being a “wet” land are explored in Figures 3.2-3.5: 1. sharp, vertical and rock floored, 2. sharp inclined and a rock floor, 3. steep and sandy, with a zone of capillary rise, 4. low inclined and sandy, with a zone of capillary rise, 5. low inclined and muddy, with a zone of capillary rise, and 6. riverine system of channel with adjoing flats. That is, the boundary is explored with respect to waterlogging and water saturation, which will have an effect on long-term vegetation response, and its limits. It should be pointed out that different vegetation types indicate boundary conditions according to the climatic, biogeographic, geological, geomorphic, and pedologic setting of a given wetland.

Commencing with a steep sided rocky basin (i.e., one without a zone of capillary rise, and where the boundary of the wetland would be sharp and distinct), there is a continuum through to basins with low gradient margins, residing in sand or mud terrains, where the boundary of the wetland becomes blurred, transitional, and indistinct. In an ideal and simple case, where a permanently inundated rock-floored basin has vertical to very steep walls (such as a volcanic crater), and no fluctuation in water level, the boundary of this type of lake will be sharp and readily identifiable. Even with seasonal fluctuation in water level, the boundary of this type of lake will be sharp and readily identifiable. With seasonal fluctuation in water level, the boundary will migrate with the seasons if the walls are moderately inclined, say a slope of 30°. If the walls of the basin are a low inclined slope, say 1-5°, then a seasonal fluctuation in the water level will result in a complex and wide zone of inundation, and irregularities in the wall will result in an irregular line for a boundary.

In locations where there is a strong seasonality in the input or occurrence of water, either contributed directly by rain, runoff, or through water table rise, the margins of wetlands oscillate laterally with the rise and fall of water levels and water tables (Fig. 3.3). In such wetlands, permanently inundated wetlands have outer zones of seasonal inundation, as well as seasonally migrating zones of waterlogging. Seasonally inundated wetlands have outer zones of seasonally migrating zones of waterlogging. Seasonally waterlogged zones have seasonally appearing and disappearing core zones of waterlogging (Fig. 3.4 & 3.5).

18 Channel-form wetlands generally have relatively steep banks and sharp boundaries (Fig. 3.6). The adjoining flats of the riverine systems are seasonally flooded, and have variable boundaries from year to year, depending on flood height (Fig. 3.6). In riverine systems there generally is a sharp boundary to the channel where it borders the floodplain, a more variable or diffuse boundary to the outer margin of the floodplain, and another diffuse boundary to the adjoining seasonally waterlogged plain.

Isolated wetland slopes often have clearly defined upper and lower boundaries at the breaks in the slope. The lateral boundaries are usually more diffuse but plant and soil indicators are often present, e.g., peat is replaced by mineral soils, clay lenses pinch out, plant species with aeronchyma are replaced by phreatophytic species. The boundary between hill crests and slopes is often much more difficult to determine, particularly if there is no change in the gradient. In addition, the hydric indicators of a hill crest are comparatively poorly developed, particularly in temperate regions, where hydrological recharge is seasonal and discharge may be rapid. In these situations, the wetland is most likely to be seasonally waterlogged and may not have strong hydric soil indicators. The boundary between the hill crest and the lower slope may exhibit a stratigraphic boundary corresponding to the relative length of time that each land form unit is waterlogged.

The boundary issues associated with seasonally waterlogged wetland plains is shown in Figure 3.7. The extent of such a plain is determined by the area of seasonal waterlogging, and can be tens of kilometres in extent. However, for degraded and modified wetland plains, the vegetated and ecologically important parts of the wetland plains are areas of remnant vegetation that often are sharply demarcated by cadastral boundaries, roads, property boundaries and fences. While these remnants are generally what is evaluated in assessments, the true extent of the wetland plain, in fact, is the full extent of the “wet” land, i.e., the full extent of the waterlogging.

3.2 Complex wetland boundaries Boundaries of wetlands can become modified by their shoreline history, the merging or nearly merging of basins, low gradient shores, and alienation.

Where the margin of a wetland coincides with complex and/or interacting sedimentary, geomorphic, or biologic processes operating at the land-water interface, the boundary of a wetland may become complicated. For example, on the margin, there may be shoreline landforms, such as shore-parallel spits, micro-mounds due to trees and other biota, and behind beachridges and spits, development of enclosed to semi-enclosed basins that connect hydrologically at the surface or subsurface. The original wetland in time may develop into one with complex margins, or into a central basin ringed by a younger set of peripheral smaller basins (Fig. 3.8).

Wetland margins become difficult to define and map where wetland systems consist of multi basins (as distinct from single wetland basins that have multi centres; Figures 3.9-3.11), or have low gradient shores. Figure 3.9 shows a gradation from clearly distinct wetland basins to a series of basins with merged margins. Figure 3.10 shows three wetlands that adjoin each other such that they appear merged, simulating a single wetland basin with multiple centres. Figure 3.11 shows a single wetland

19 basin with an undulating floor that results in a basin with multi centres. Semeniuk et al. (1990) suggested that the distinction between wetlands that have multi centres and a series of merged wetlands be based on criteria that if the deeper “centres” of lakes or seasonally inundated basins comprise more than 5% of the wetland basin, they should be treated as separate basins, and/or if the basins are separated by any supralittoral zone.

Low gradient shores compound the difficulty in delineating a wetland boundary. Intially it is a matter of the water line or the zone of wetted soil interacting with a low gradient slope with small scale undulations resulting in mottled shores, crenulate shores, and diffuse shores. The boundary becomes more complex if the shoreline is composed of varying sedimentary and soil materials, resulting in differential response to capillary rise and wetting. The boundary becomes even more complex in situations where the shoreline vegetation differentially responds at species level to the complexity of soils, their porosity, retention of moisture over the year, and response to drainage rates effected by variable slopes.

A variety of idealised diagrams of boundaries of basins with steep to low gradient shores, and river or creek systems, is shown in Figure 3.12.

Alienation of wetlands by degradation or clearing of wetland vegetation can obscure the boundary of a wetland (Figures 3.13-3.15). In assessing a basin, the boundary of the wetland is the extent of the “wet” land, and the degree of alienation should be considered within this boundary. The boundary between alienated and natural wetland is not the boundary of the wetland but a boundary between degradation and unaltered sectors of the wetland. In assessing a riverine system, consisting of channel and adjoining flats, the boundary of the wetland again is the extent of the “wet” land, and the degree of alienation should be considered within this boundary. As with the basins, the boundary between alienated and natural wetland for the channel and adjoining flats is not the boundary of the wetland but a boundary between degradation and unaltered sectors within the riverine wetland complexes.

Figure 3.13 shows a wetland basin under increasing effects of alienation (which may include wetland vegetation clearing and/or soil disruption). In the first instance, with intact native vegetation, the wetland boundary is determined by criteria of vegetation, hydric soils, and hydrology, and in this case it is clear that it is a “wet” land. When a small part is alienated, the small part of the alienation is seen to be simply part of the wetland that is degraded. As the wetland, within the confines of the wetland boundary, becomes more alienated, the area of “wet” land remains the same. There is sometimes a perception that because the vegetation has been degraded the wetland ceases to exist, or that only undegraded parts of the wetland are still true wetland, or that only undegraded parts of the wetland need to be assessed. Actually, viewing relative and progressive degradation within the boundary of the wetland allows one to assess the entire wetland as being progressively degraded and alienated. In Figure 14, the final stage of the alienation is a wetland, confined within a wetland boundary, composed of “wet” land that is wholly degraded.

Figure 3.14 shows the boundary of basin, channel-and flat (riverine), and other wetland plains with natural vegetation intact, and with areas of alienation within the wetland. Included within this boundary, even though the interior of the wetland may

20 be alienated, are parts of wetland that may be still significant ecologically in terms of vegetation, ground fauna, and avifauna. In this latter context, seasonally waterlogged flats and plains present a particularly difficult problem for assessment because the degraded wetland plains (cleared and pastoralised sections) may support abundant avifauna (even if that avifauna are opportunising the pasture sections, and that the composition of the avifauna populations are not wholly natural.

Figure 3.15 shows the variable situations of vegetation of basin wetlands that may be intact, or disturbed, or alienated, or revegetated, and the location of the wetland boundary for each situation.

3.3 Natural fluctuations of wetland boundaries Wetland boundaries can fluctuate on an intra-seasonal, annual, or longer term basis, driven by climate cycles and patterns, or by hydrological processes outside the region. In this context, the fluctuations may result in various positions of the wetland boundary.

The boundary of a wetland determined by hydrologic, pedogenic (hydric soils), and vegetation criteria is illustrated in ideal form in Fig. 3.1 the effect of fluctuations in these boundaries in shown in Fig. 3.16. In effect, the wetland is demarcated by three boundaries, and each has its own measure of stability and response to fluctuating environmental conditions. Each of these boundary criteria are described and discussed below in order from least reliable to most reliable, in terms of their expression, their stability, their reliability in delineating boundaries in the long term.

Using hydrologic criteria, i.e., the wetland surface is inundated or waterlogged, the boundary of a wetland is delineated where all water regimes are encompassed for all seasons. Hydrology can generate a clear and unambiguous boundary to a wetland where there is a sharp waterline. The waterline can be ambiguous and difficult to delineate accurately where there is a low gradient shore. Waterlines also can grade into saturated soils and wet zone, with the boundary becoming blurred. However, all waterlines can fluctuate and respond rapidly to short term climatic effects (e.g., rainfall and evaporation), and hence can vary from year to year, or intra-seasonally, and hence, while at one extreme they are often clear indicators of the boundary of a wetland at a given time, they are not reliable as long term markers. Wetland boundaries also can be delineated by wetted soils, generated by capillary rise, or moisture retention, and similarly, these boundaries can be sharp, or along low gradient shores, broad and diffuse. Like waterlines, wetted zones can fluctuate and respond rapidly to short term climatic effects, varying between the years, or even intra-seasonally. They also are not reliable as long term markers.

Vegetation is a variable indicator of a wetland boundary, with some opportunistic and shorted-lived species responding to short term climatic and water level fluctuations, and other longer-lived species adapted to accommodating longer term fluctuations in environmental conditions. Opportunistic and/or rapidly regenerating species, such as rhizomatous and cloning sedges, relying on root extensions an culm propagation can migrate with a year or two into wetter or drier environments along the boundary of a wetland that is experiencing water level and wetness fluctuations in response to climate variation. Like the waterline, these species, while providing

21 an indication of the location of a wetland boundary in the very short term for a given year, are not reliable indicators of the long term position of the boundary. At the other extreme, longer lived species, such as trees and shrubs that have longevity in excess of, say, 100 years, and especially those species adapted to accommodate fluctuations of wet and dry in th environment, provide a more reliable indication of the location of a wetland boundary in long term.

Hydric soils and sediments often are markers of specific water levels and can function as indicators of water level regime. Since they are generally slowly accumulating and developed over hundreds of years or millennia, they potentially can provide a more consistent indicator of wetland conditions and the boundary of a wetland, and are the most reliable long term indicators of a wetland boundary. Some wetland sediments and soils are very stable, e.g., diatomite, and carbonate deposits, and are reliable long term indicators of wetland conditions. Other substrates, such as peats, can burn away, or be oxidised, during dry phases of climate cycle, returning on a circa 20 year or 250 year cycle, and hence may not be a good indicator of the long term boundary of a wetland. However, ibecause wetland soils and sediments can be so stable over millennia, there may be deposits along wetland margins from earlier times, that may signal former higher water levels several thousands of years ago.

3.4 The boundary of coastal wetlands Coastal wetlands are tidally inundated, and hence a simple criterion for their boundary is the position of equinoctial high spring tide (EHW) for their upper boundary, and equinoctial low spring tide (ELW) for their lower boundary (Fig. 3.17). In this context, however, it is clear that the tidal zones between EHW and mean high spring tide will spend a large proportion of the time not flooded by marine waters (though potentially, and often wetted by tidal groundwater). Similarly, the zone between mean high spring tide and mean high neap tide will spend a lesser proportion of the time each fortnight not flooded by marine waters (though often wetted by tidal groundwater). Conversely, the tidal zones between ELW and mean low spring tide will spend a large proportion of the time under shallow marine waters, and the zone between mean low spring tide and mean low neap tide will spend a proportion of the time each fortnight flooded by marine waters.

Low gradient shores provide the same complications to delineation of the boundary of a coastal wetlands as they do for inland wetlands, with crenulate, mottled and diffuse boundaries developed along the land-sea interface. Coasts frequently exhibit complex shores (with spits, lagoons, shoals, sedimentary fans, tidal creeks, amongst other coastal landforms) because of the interaction physically, chemically and biologically between the media of land, sea (waves and tides), and winds, and here mosaics of smaller scale complex coastal landforms along the shore can further complicate the location of the coastal wetland boundary, making it difficult to ascertain and map. For instance, a muddy tidal flat with a series of supratidal low relief sand ridges, can be mapped out as a mottled mosaic or series supratidal units scattered across the tidal flat, or the whole ensemble mapped as a “strandplain”.

Larger scale coastal systems, such as estuaries and deltas, provide another complication to delineating a boundary to a coastal wetland in that they are large

22 scale constructed landforms, marine at their seaward end, and riverine influenced at their landward end, or for deltas, grading from tidal to fluvial. There also is the issue of scale. At the large scale, deltas and estuaries are discrete units, and can be viewed as a single integrated coastal wetland units, and hence the boundary to these systems logically would be drawn around the entire delta or estuary. However, at the small scale deltas and estuaries carry a plethora of smaller scale landform units within which there is the potential for the low tidal to high tide transition to be developed.

In this context, the simplest wetland to identify, map its boundary is the steep shored lake. The most difficult wetlands to map and determine boundaries for are those with inter-merging, multiple basins and flats, and low gradient shores. While there is no real difficulty in determining that such terrain is “wet” land, the difficulty lies in determining where individual basins lie. This becomes particularly so if such wetlands are partly degraded, because workers and land managers generally cannot identify wetlands when cleared.

The problem of wetland boundaries noted above has been discussed in the literature elsewhere. In the European literature, peatland complexes are often described where bogs are bordered with, or surrounded by, narrow to extensive areas of wetland zones that are not ombrotrophic-sustained. When narrow these zones are referred to as “laggs” (Gore 1983), when extensive they are denoted as a separate wetland termed a “fen”. In the USA, Tiner (1999) discusses in some detail, the issues of inland wetland boundaries, and suggests that the wetland boundary needs to be determined by use of hydrologic, pedologic and vegetation criteria. Some authors argue that all three need to be used (cf. Sipple 1988; Tiner 1993), but others view that only one of the three need be satisfied (refs). Authors tend to agree that the hydrologic criterion is the least stable for determining boundaries. The delineation of estuarine boundaries is equally controversial and the history of estuarine studies is filled with debate about definition and delineation (Pritchard 1967, Fairbridge 1980, Pethick 1993, Cooper 1994, Jay et al 2000, Elliott and McLusky 2002).

23 4.0 Review of wetland classification schemes, and case studies

This section reviews a number of wetland classification systems, with the objective of tracing some of the concepts, approaches, and terms that underpin them. This is followed by a description and review of selected wetlands as case studies to illustrate difficulties with current classifications. While the focus is on inland wetlands, the principles herein apply equally to coastal wetlands.

4.1 Review of classification systems This present review cannot hope to include the majority of wetland classification schemes as they are far too numerous. Rather, what has been selected for discussion are those that have had far reaching affects on the way wetland ecologists have perceived wetlands and/or classification. Reviews previously undertaken of classification schemes abound (Laine 1982, (under Heikurainen) Gore 1983, Wetzel 1983, Semeniuk 1987, Pressey Mader 1991, Brinson 1993, Finlayson & van der Valk 1995, Tiner 1999), and the reader is referred to these works to obtain other perspectives.

Tiner (1999) provides a thorough up to date review of the classification of wetlands. Tiner (1999) recognises two designs in wetland classification: horizontal and hierarchical. Categories of the horizontal design are described as necessarily being general and limited in number, and their objectives as being varied and often responsive to the requirements of the local community or state government body. They have great appeal because of these attributes, and many terms from these systems are entrenched in cultural usage. Categories of the hierarchical design are described as ranging from general to more detailed and specific in form as the classifier proceeds from lower to higher levels. These designs can accommodate greater numbers of types and their objectives are usually to achieve systematic and consistent division of types according to the codes of scientific method. However, the terms are often unfamiliar to the wider community and to decision makers who are untrained in such methods.

That classification systems for wetlands are being constantly developed testifies to the ingenuity of wetland scientists and their frustration with the current schemes available. However, it seems that there are several points of consensus which can be drawn from the history of wetland classification. Firstly, hierarchical schemes are preferred to horizontal schemes for the reasons that they lend themselves to systematic organisation, and that greater complexity and number of attributes may be incorporated. This is important in the recognition of wetland diversity. Secondly, increasing recognition is being given to the fundamental attributes of water and land, and their contributing effects on important wetland processes such as chemical recycling and generation of precipitation/dissolution cycles, as well as recognition of the link between water, land and the biological responses expressed in species composition, vegetation and faunal structures, and ecological processes.

Table 1 summarises the elements, advantages, disadvantages, and effect on later schemes of selected classifications of inland and coastal wetlands, and the various overlapping categories of wetlands underlain by peat (peatlands).

24 Table 1: Summary of the main attributes of the various classification schemes developed to date Classification Form and Criteria Advantages Disadvantages Schemes deriving Scheme from this Shaler 1890 Hierarchical design: Recognition of a linked system Not comprehensive in terms of The use of many • Inundation wetland or vegetation or terms in subsequent • Inland vs coastal hydrological types horizontal designs, • Process of formation Inconsistent use of criteria e.g., Bulman 1952; and maintenance Galkina 1963 • Landscape position and vegetation Davis 1907 Horizontal design: Recognised the importance of the Not comprehensive in terms of Cajander 1909, 1913; • the landform on which landform component wetland or vegetation types Radforth 1952, 1962, the bog developed 1977; Moen 1985 • the method by which the bog developed • surface vegetation Weber 1908 Horizontal design: Linked vegetation to water attribute The category of fen encompasses Tansley 1939; Potonie 1908 • ontogeny Relatively widespread applicability too disparate and large a group of Kulczynski 1949; Du cited in • plant nutrition wetland types Rietz 1949; Sjors Clymo (1983) • source of water Non peat based wetlands are 1948; excluded Moore & Bellamy 1974; National Wetland Working Group of Canada 1987, 1997

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Classification Form and Criteria Advantages Disadvantages Schemes deriving Scheme from this Warming Hierarchical design: Consistent use of criteria Not comprehensive in terms of Inland/coastal types 1909 • Salinity wetland or vegetation types Martin et al 1953; • Vegetation Troublesome transitional types Vegetation association Stewart & Kantrud 1971; Golet & Larson 1974 Chrysler 1910 Horizontal design: Recognised the importance of Not comprehensive in terms of Deuse 1966; • plant life form internal zonation within wetlands wetland or vegetation types Cowardin et al 1979 • soil type Separation and classification of • landscape position zones from wetlands Partial use of genetic criteria Shreve et al Horizontal design: Increased recognition of diversity Not comprehensive in terms of Martin et al 1953 1910 • plant life form wetland or vegetation types Zoltai & Pollett 1983 • soil type Inconsistent use of criteria • landscape position Dachnowski Tried to eliminate poorly defined Classified peat deposits not 1920 hydrological terms wetlands Related peat type to an assemblage Used circular logic to relate peat of plants type to an assemblage of plants, assemblage of plants to wetland where they occurred, and then used a mix of vegetation structural terms and wetland terms to describe the peatland

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Classification Form and Criteria Advantages Disadvantages Schemes deriving Scheme from this Cowardin et al Hierarchical design: Emphasis on being comprehensive Hydrologic regime was not applied Ramsar classification 1979 • System Emphasis on systematics to the palustrine system • Hydrologic regime Appropriate choice of attributes It divides a single wet entity into • Habitat type based on Use of modifiers for greater detail types of wetlands vegetation and/or Grapples with the problem of large It classes small scale habitats and substrate scale features crossing zones of a single wet entity into • Soil type and physiographic and climatic types of wetlands matching the vegetation structural boundaries boundaries of a vegetation categories Can be mapped at the class scale association • Species composition Includes modifiers for special cases Lack of terminology for wetland of modified wetlands types Wharton et al Hierarchical design: Uses fundamental attributes of land Omits perched wetlands Schemes of 1976 • Water driven energy and water Water driven energy is sometimes a discharge etc. • Landscape forms Consistent use of criteria; energy is difficult attribute to relate to Gosselink & Turner used as a common denominator ecological response 1978; Odum 1978; Addresses the whole system rather Novitzki than just the components 1979;Kangas 1990 Semeniuk Hierarchical design: Emphasis on systematics Not yet comprehensive although Brinson 1993 1987, 1995 • 3D landform geometry Uses fundamental attributes of land scope exists Davis & Anderson coupled with and water Landform classes can grade into 2001 hydroperiod Consistent use of criteria one another • Scalar, salinity, water Small number of classes source, stratigraphic, Simple well defined terminology & vegetation Can be mapped at the class scale descriptors Can be related to ecological response

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Table 2: Classification of mounded wetlands Classification Form and Criteria Advantages Disadvantages Schemes deriving Scheme from this Kats 1971 • structural peculiarities of Recognition of such mires as biogenic Classification restricted to peat mire formations formations on the surface of mineral formations • average thickness of peat strata Incorporation of vegetation into deposits primary divisions particularly in zones of deficient moisture

Table 3; Classification of fluvial wetlands Classification Form and Criteria Advantages Disadvantages Schemes deriving Scheme from this Horton 1945, • genetic relationship to Drainage basin components could be Can not be applied to non-fluvial Strahler 1964 landform classified wetland types Can be related to water permanence Demonstrated that channels could be analysed as segments Leopold et al • sinuosity Can be related to hydrological This attribute is better applied at a 1964 attributes secondary or lower level of wetland classification Schumm 1977 • sediment transport mode Related channel pattern, bedload and Hydrological attributes are implicit channel stability Does not provide a foundation for Addressed fundamental attribute of habitat differentiation land and incorporated its dynamic nature Frissel et al • water quality Functional classification More relevant to assessment than Urban river 1986 classification classifications

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From the range of classifications noted above it is evident that the most commonly used features to identify and further classify wetlands are vegetation, hydrology, origin of water, water chemistry, origin of wetland (specifically lakes and rivers), soil types, landscape position, and landform. These are discussed below.

As pointed out by many writers, vegetation is a useful and easy way of identifying wetland habitats (Davis 1907; Cajander A K (1913) cited in Pakarinen (1995); Tansley 1939; Du Rietz 1949, 1954; Jeglum et al 1974; Gore 1983; Palmer 1992; Kennison et al 1995; Pakarinen 1995). On the basis of its usefulness in identification, it has often been selected as a component of wetland classification. Physiognomy, life-form, structure, community composition, abundance, and arrangement of plant associations have independently and conjunctively been used to classify wetland habitat. Wetland habitats are referred to by a number of vegetation associated terms: salt marsh (Spartina spp., Juncus spp.); wet meadow (Pennisetum spp.); marsh (Phragmites spp., Carex ssp., Eliocharis spp.); swamp (Acer spp., Betula spp., Melaleuca spp.); and bog (Sphagnum spp.). Vegetation itself is ideally suited to classification and this often prompts the idea of extending such an ordered body of data to classification of what is inherently a landscape feature (Semeniuk 1987, Brinson 1993).

However, several criticisms of the use of vegetation in wetland classification as a fundamental distinguishing characteristic are re-iterated here. Firstly, vegetation pattern is the response of living organisms to a set of environmental factors within the boundaries set by species competition (van der Valk 1981). As environmental factors are constantly changing, its nature is inherently dynamic in the short-term (Stewart & Kantrud 1971; Semeniuk 2002). Thus any vegetation based-classification would need to be constantly updated. Secondly, species composition is determined to some extent by the regional pool which varies both spatially and temporally. The species which colonise a specific type of wetland in one physiographic/climatic region may not be the same that colonise the same type of wetland elsewhere. In terms of capturing vegetation diversity, this distinction is important. In terms of recognising wetland diversity, it is confusing and misleading. Thirdly, in historical phytosociological research and mapping, the scalar units selected for observation and analyses have often varied, resulting in incompatible classifications and incomplete comparisons (Pakarinen 1995). Fourthly, in some vegetation classification systems, the use of vegetation type as the fundamental criterion for wetland segregation results in differentiation between topographically dissimilar zones of a single wetland (Malmer 1986, Davis & Anderson 2001). This practice further reinforces the erroneous interchange of the concepts “wetland” and “wetland zone” Two minor criticisms are also expressed here. Botanists and ecologists normally restrict vegetation analyses (and subsequently, classification) to macrophytes, ignoring microflora which in some cases have proven to be significant, e.g., algae (Kennison et al 1998), diatoms (Timoney et al 1997), and wetlands exist in which macro vegetation plays a very minor role, e.g., salt lakes, mud flats, entrenched rivers.

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A very popular classification method employed in wetlands involves the identification of plant associations with selected environmental parameters. For example, the “low prairie zone” of Stewart & Kantrud (1971), comprising the following genera of grasses and rushes, Poa, Agropyron, Anemone, Aster, Solidago, Ambrosia and Symphoricarpos, is characterised by a very brief hydroperiod and freshwater. Using the plant association as an indicator of these hydrological conditions, wetlands, wherein this plant association is present, are then classified hydrologically. This method is sometimes extended to encompass water regime, water salinity, and substrate. In local regions, this method appears reliable, straightforward, and requires comparatively minimal training in order to apply it. However, although appearing straightforward, the underlying assumptions and premise of the methodology, which is that all wetland species comprising an association are equally dependent on water availability, and that this factor is the decisive one in determining species distribution, cannot be sustained. Recent research, in which the response of plant species to a single environmental attribute was investigated, showed that this response can be highly variable, with differences occurring throughout species of a single genus, and at different periods within the life cycle of a single plant (Justin & Armstrong 1987, Blom et al 1994, de Kroon et al 1996, Visser et al 2000). It has also been shown that some species may be indifferent to selected hydrological attributes (in this example, water depth and permanency), and their distribution controlled by some other factor (Semeniuk 2002). Wetland classification based on diversity of plant associations often require augmentation by classes based on an entirely different set of criteria, e.g., alkaline wetlands (Stewart & Kantrud 1971). In order to keep a pragmatic number of wetland categories, a wetland classification scheme based on identification of plant associations can only ever be applied to a region with constant species pool and environmental conditions. For wetland classification to be successful over a broader spectrum, it is preferable to eliminate the complex layer of vegetation community classification and deal directly with the determinative attributes.

Hydrology fundamentally underpins wetlands (Semeniuk 1987), and as such should feature in any wetland classification. Various aspects of hydrology have been used historically, e.g., water regime (Stewart & Kantrud 1971, Millar 1976, Semeniuk 1987, Cowardin et al 1979); water flows, viz., discharge, throughflow, recharge (Ivanov 1981); water depth (Martin et al 1953; Cowardin et al 1979); hydrological mechanisms (Semeniuk 1987; Brinson 1993); origin of water, viz., precipitation, snow melt, groundwater; and water chemistry (Kulczynski 1949, Bellamy 1959). In the case of water chemistry and its trophic status, waters have sometimes been classified as to their source (ombrotrophic/oligotrophic and minerotrophic; Du Rietz 1954, Moore & Bellamy 1974, Masing 1975). Although it has been argued that the division of wetlands into freshwater and saline types is inappropriate when considering the definition of wetlands, it can be used to recognise at the large scale land based, marine based and intermediate (estuarine) wetlands. In the majority of these wetland classification schemes there are very few categories (} 3) which results in the contraction of wetland diversity. However, water regime, i.e., the frequency and duration of inundation or waterlogging has six categories (permanent, seasonal, or intermittent inundation, and permanent,

30 seasonal, or intermittent waterlogging). In estuarine and tidal flat wetlands, tidal regime and fluctuation can be used.

Wetland origin or genesis has been used mainly to classify types of lakes and streams (Hutchinson 1957, Bayly & Williams 1973, Wetzel 1983). Categories of lake origin were based on Earth building processes and included tectonic, glacial, and deflation types. In the second example, streams were classified as obsequent, subsequent and consequent also with regard to Earth movements. These classification styles are useful in demonstrating the diversity of wetland forming processes but gives little indication about the nature, characteristics, or functions of any extant wetland or the processes which currently maintain a given system.

Wetland soils have been used to classify wetland types in two ways: 1) as a wetland product, diagnostic of a set of environmental conditions, and 2) as an attribute of the wetland with distiguishing properties. In the first approach, the object is the soil forming system comprising water chemistry, flow rates, temperature, oxygen, and plant species. This approach has been commonly used to differentiate wetlands underlain by organic soils (“mires” or “peatlands”) and this subset is further subdivided using attributes of soil or water chemistry and vegetation. The second subset of wetlands, i.e., those underlain by mineral soils has not been named, nor has a universal system of further subdivision been constructed which corresponds to that of “peatlands.” The result has been that organic soils have been useful in identifying wetlands and delineating their boundaries, but have been less useful in classifying wetlands. In the second approach, the object is the nature and composition of the wetland fill, i.e., whether it is organic, iron rich, calcareous, or coarse textured. Although organic and mineral soils can be classified (Botch & Masing 1983, Shotyk 1988, Richardson & Vepraskas 2001), they tend to occur together in stratigraphic sequences rendering any classification of wetlands on this basis unworkable. Mineral soil subdivisions are composed of numerous permutations and combinations, some of which alter laterally within the wetland or along its length.

In terms of landscape position and landform, geomorphology is a component of all terrestrial systems, and underpins the sciences of pedology and ecology. A classification scheme which incorporates geomorphology is therefore addressing a fundamental aspect of any terrestrial system, or in other words approaches its determining and essential nature. There are of course a number of facets to the aspect of geomorphology which could be selected for use in classification (and these relate to the form of the land, its scale, and the scale of observation involving differing assemblages of landforms): landform geometry, geomorphic unit, scale of landform, physiographic region. In the realm of wetlands, many authors, rather than using landform directly, have referred to some other related attribute which is linked to the position within the landscape occupied by the wetland, e.g., the hydrologic classification of Moore & Bellamy (1974). This particular attribute has been one of the most important for classifying estuaries and coastal wetlands and is used in a variety of ways (Semeniuk 1987, Davidson et al 1991, Dyer 1996, Edgar et al 2000). Semeniuk (1987), for instance, classified the mangrove assemblages in Western Australia initially with respect to geomorphic units linked to substrate types (e.g., muddy tidal flat, sandy tidal flat, mid tidal alluvial fan, high tidal

31 alluvial fan), as these through tidal level, groundwater salinity and soil type determined the species composition and physiognomy of the mangrove communities.

Wetlands are a component of the land and, in the first instance, require a land-focused classification scheme (Kangas 1990, Semeniuk & Semeniuk 1995, Lindsay 1995, Davis and Anderson 2001). For example, peatlands, just like any other wetland, are discrete morphological/hydrological units occupying a landscape depression or one segment of a depression (crest, slope or flat). Even “blanket peatlands” are the result of peat development over a number of landform types merging into a continuous surface expression of waterlogged or inundated land (Fig. 1.4). In discrete morphological/hydrological units, zonation frequently occurs due to gradients in hydrology, hydrochemistry, biogeochemistry and vegetation. For inland wetlands, these zones conform to permanently inundated, seasonally inundated and seasonally waterlogged habitats (Semeniuk & Semeniuk 2003). In coastal wetlands, the zones conform to salinity gradients, soils, and inundation regimes related to subtidal, intertidal and supratidal environments, intertidal being further subdivided into low, middle and high tidal sections (Semeniuk 2004). In estuaries, zones often correspond with non-tidal, and tidal freshwater, mesohaline, polyhaline and euhaline boundaries (Elliott & McLusky 2002).

The perception has developed that these zones in the various wetland environments mentioned above represent either a number of juxtaposed wetland types (Cowardin et al 1979)) or a “wetland complex” (Ivanov 1980, Davis and Anderson 2001). This has resulted simultaneously in a reduction and overestimation of the diversity of wetland types. Reduction in the estimate of diversity has occurred where large areas of apparently relatively homogeneous wetland vegetation cover several landform types masking small scale differences in processes, history, or hydroperiod. Various authors have tried to address this view of a uniform large habitat by subdividing such areas on the basis of surface geomorphological patterns (Cajander 1913 cited in Botch & Masing 1983, Ivanov 1981, Zoltai & Pollett 1983). Reduction in the estimate of diversity has also occurred by overlooking the possibility of differentiating wetlands using the various distribution and arrangement patterns of vegetation brought about by different plant structures and composition, e.g., concentrically zoned wetlands, wetlands with patchy or complete homogeneous cover etc. (Golet & Larson 1976, Semeniuk et al 1990). These patterns often give indications of gradients and processes, which themselves can be diverse. Overestimation of wetland diversity has occurred by equating wetland zones with wetlands, and has resulted, with the ensuing large number of categories, in difficulties in classification.

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4.2 Review/discussion of some case studies, Several case studies have been selected for review and discussion to illustrate difficulties with current wetland classifications, and to demonstrate some unresolved problems in classification of wetlands. One of the objectives of this selection has been to balance the geographical distribution of examples in order that readers will be familiar with at least one of them, while at the same time endeavouring to demonstrate a range of problems issuing from application of the current classifications and terminology. The examples are Askham Bog near York in southern England; Cottonwood Lake area North Dakota, USA; the alpine lakes Thunersee, Oschinensee and Bachalpsee in the Swiss Alps and at Luzerne, and the lakes of the Snowdonia region, North Wales; the meadows of cut peatlands in the Bogs of Allen, Co. Kildare Ireland; blanket bogs in Co. Galway Ireland;; wetland slopes in the Italian Alps, wetland plains of the Swan Coastal Plain in Western Australia; and the hill-top wetlands in Walpole, southern Western Australia.

Each of the selected wetlands are described below in terms of their overall setting, history, and classification problems.

4.2.1 Askham Bog Askham Bog (circa 1.5 km by 400 m in size) is a single wetland basin, and is a “a relic of the former fen vegetation and fauna of Yorkshire” initially comprised 6 parts: old brick ponds; marshy meadow; three woodland areas separated by tracks and an area of bog (Fitter & Smith 1979).

Askham bog has a long natural history and a relatively long history of landuse spanning 2,000 years. As a result of natural and anthropogenic influences, the vegetation, hydrology, hydrochemistry, and geomorphology of the wetland have changed. Four stages of natural wetland development can be recognised in the stratigraphic column: an early stage in which the wetland was probably perched or ponded; a secondary stage in which ponding became permanent and a lake developed; a stage in which shallow inundation became established, followed by a stage in which waterlogging and a shallow water table prevailed. Subsequent to these developmental stages, activities such as peat mining, logging and draining have altered the sedimentological, hydrological and hydrochemical environment and consequently, the plant composition and distribution.

Several aspects of the wetland’s classification as “bog” require some discussion. Today, there is no area or zone which could be identified as “bog,” and indeed, for much of the wetland’s history it did not function in this way. The greater portion of the wetland sediments are muds/clays rather than peat. The cross-sectional diagram illustrated in Fitter and Smith (1979) is that of a basin. Using the criterion of geomorphology, the basin can be shown to have more than one convex surface. Does this constitute a “bog” or an undulating surface which can occur under many types of vegetation? On the criteria of vegetation and hydrochemistry, what fraction of the wetland should constitute “bog” before it is termed “bog,” or is each zone of the basin classified as a separate wetland? Was Askham Bog a bog-fen complex? It is currently most akin to a “fen”; on hydrochemical criteria, plant communities and water source. The extant vegetation

33 comprises dense stands of trees which are largely a factor of nutrients imported through drains. Should the wetland be classified on the quality of present water input or on historic water input? If the latter, then which developmental stage should be considered representative?

4.2.2 Cottonwood Lake area, North Dakota, USA The Cottonwood Lake area of North Dakota provides an expedient example to illustrate why vegetation should not be used as a primary classifier of wetland types, as presented in the case study by La Baugh et al (1996). The Cottonwood Lake area is a mosaic of seasonal and semi-permanent fresh and saline wetlands with various plant communities in a semi-arid climate zone.

A history of drought and deluge has been documented in the area since 1978, due to variation in the timing and intensity of rainfall and snowmelt (characteristic of this climatic zone). In their observation of three semi-permanent wetlands, plant associations were found to be dynamic over a period of 27 years. Emergent vegetation that covered the mudflat of each wetland following dry episodes was not the same for each episode. After a change in precipitation pattern, changes in vegetation distribution and composition occurred as early as the following season, and persisted until the next extreme rainfall event, because, in tandem with the hydrological changes, a shift was induced in the relative abundance of major ions. Different plant responses to changes in hydrochemistry in the dry periods were due to the modifying influence of three factors: basin geometry, proportion of groundwater to surface water recharge, and timing of rainfall events.

Although the hydrological state of all three wetlands changed from inundation to exposed mud floor, each biological response was independent. Classification of the wetlands using plant associations would have resulted in each of the three being classified as a different wetland type for part of the period and the same wetland types for the remainder. In areas where extreme swings in precipitation, frequency, and volume, are recurrent, this situation is not uncommon.

4.2.3 Swiss Alpine lakes The effect on wetland classification resulting from emphasis on ancestral processes is illustrated in this next example, located in the sandstone and shale regions of the Swiss Alps. In this area, the upper slopes exhibit glaciated structures such as cirques, hanging valleys, dipping planes, slip slopes, scree slopes, and waterfalls, while the lower slopes are fluvially dominated with interlocking spurs, alluvial fans, and scree slopes, their valley tracts composed of broad alluvial plains, channels and linear lakes bounded by bedrock with narrow constrictions commonly caused by alluvial fans.

The down-slope bifurcation of the valley tract lakes and their bathymetry suggest a glacial origin for the valley tract, but the configuration and height of some of the marginal deltas that debouche into the lakes suggest that these latter features may not be

34 related to the present sedimentary regime but linked to a former lake level and sedimentation pattern. These lakes are now under the influence of fluvial processes, and may have been for some time. While the lakes occur in valleys with interlocking spurs, there also are some in flat floored valleys. Many of the lakes are interspersed along valley tracts, and except for the weirs, could be viewed currently as a through flow system.

The array of the lakes provides a classification conundrum. Are these wetlands correctly viewed as lakes connected to each other by channels, or as a channel, which in some settings and sections of its thalweg, broadens and deepens into what could be called a lake? Is the projected origin of the valley determining the classification of the wetland in this example?

The lakes in the Snowdonia region of north Wales occur in a similar setting to the lakes at Luzerne and Bachalpsee and provide a further example in which similar questions about wetland classification may be asked.

4.2.4 Glacial lakes of Wales and England Further examples are drawn from Wales and England to demonstrate the problems on wetland classification where there is anthropogenic alteration of fundamental functions such as hydroperiod. In the mountainous, formerly glaciated areas of Wales and England, at the junction of several spurs or ridges, where adjacent slopes form a semi- closed or constricted depression in the landscape, water from the higher uplands discharges into a depression forming a rounded “lake”. When the depression is composed of bedrock, surface water from short in-flowing rivers and creeks augment the volume of discharge and the length of time over which discharge occurs.

Under natural circumstances these currently inundated areas would probably only have been seasonally inundated, or where a layer of colluvial material overlies the bedrock, permanently waterlogged. However, with the construction of weirs and floodgates to control the waters at the natural point of constriction, these areas have become lakes.

Are these systems natural lakes, semi-natural lakes, or artificially constructed lakes?

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4.2.5 The Bogs of Allen, Ireland The Bogs of Allen provide one of the many widespread examples of the anthropogenic alteration of natural wetlands, and a clear example where the wetland classification may no longer be appropriate. The bogs of Allen are large scale wetlands with convex surfaces landsurfaces and shallow water tables. They are underlain by several metres of heterogeneous layers of peat and support plant species which are typical of “bog” environments, viz., mosses and heath.

The cutting and removal of peat in many sites in this system has lowered the surface of the bog and simultaneously altered the local hydrological regime. Plants which colonise the topographically lower sites are typical of “fen” environments.

On the basis of the criteria used to designate such sites, i.e., vegetation, hydrology, and hydrochemistry, at what point does the “bog” become a “fen”? Should the wetland designated by geomorphic boundaries be considered a single wetland with heterogeneous zones or should the region be viewed as several wetlands juxtaposed against each other?

4.2.7 Wetland slopes in the northern Italian Alps The steep valley walls of the mountainous region of the northern Italian Alps, e.g., Val Strona, provide an example of wetlands common to this region. The climate is humid, with rainfall and snowmelt contributing to seepage along the valley walls. There is local development of (steep) water saturated wetland slopes, underlain by muddy gravel, and vegetated by a diverse assemblage of wetland herbs.

Generally, in this region, the steep valley walls, though potentially classed as a “wetland” because they are colonised by wetland vegetation, are not actually captured or described in any wetland classification. .

4.2.8 Foothills to the Darling Plateau, Western Australia Wetlands developed along the foothills to the Darling Plateau, in Western Australia provide examples of wetland types which are omitted from most widely used and current classifications. At the base of these foothills, there is a geomorphic surface which is flat to gently undulating, incised by small scale transverse channels, and underlain by a zone of alluvial sediments and aeolian sediment both diagenetically altered by groundwater. This zone is ribbon shaped and extends over 300 km from north to south, and while it is generally identified by its geomorphic consistency, it is composed of a myriad of soil types and very small scale (< 30 cm) rises and hollows. Much heterogeneity of the plant assemblages thereon is expressed in composition, life form, and structure, with patchy occurrences of many rare flora .

Using current wetland classification schemes, this wetland is difficult to classify. On geomorphic criteria, it is simply a flat which is seasonally waterlogged (= palusplain of Semeniuk 1987). In terms of its landscape setting, it is a discharge wetland. In terms of

36 soil type, it is difficult to characterise because of its heterogeneity. In terms of vegetation it ranges from forest to scrub to heath to sedge to herbs, and exhibits many transitional areas. In terms of hydrochemistry, it is also variable, as the different sources of water and the variable stratigraphy through which the groundwater passes, alter its quality. It is not a rock bottomed wetland nor is it underlain by unconsolidated sediments. It is not aquatic, nor related to a shore. It is not a moss-lichen, emergent, scrub/shrub or forested wetland, although it exhibits all of these characteristics.

4.2.9 Hill-top wetlands, southern Western Australia Examples of wetlands, this time from the southern part of Western Australia, where annual rainfall is above 1,400 mm per annum, are used here to illustrate types which also are omitted from most widely used and current wetland classifications. In this humid region, the tops of hill are sometimes wetlands, being waterlogged for the winter and spring each year, the sources of the water being rainfall, and locally, artesian water. Soils underlying these wetlands are clayey sand or humic sand, and the vegetation comprises wetland trees, shrubs, sedges, grasses and herbs.

Generally, hill-top wetlands elsewhere in the world are located in very wet environments culminating in the development of blanket bogs that mantle hill and dale. Generally, very wet environments, if they can create hill-top capping wetlands, will also be wet enough to create bogs. Thus, hill-top wetlands often are synonymous with blanket bogs. However, the hill-top wetlands of southern Western Australia are not part of a “blanket bog” system, being underlain not by peat but by muds and muddy sands. On geomorphic criteria, they are simply hills which are seasonally waterlogged enough to support a mixed wetland vegetation assemblage of trees, shrubs, sedges, grasses and herbs. In general terms, these wetlands are not captured by other wetland classifications, beyond being classed as a “wetland”.

4.2.9 Discussion This review of selected wetlands across Europe, Australia, and the USA provides several important insights into wetland classifications systems and their problems.

Firstly, not all wetlands are captured by current classification schemes. The examples from Val Strona in northern Italy and the wetland plains and hill-tops in Western Australia illustrate this. In all these cases, the vegetation is hygrophilic, and ecologists probably would recognise the environment as wet habitat but without the vegetation signature, most classification schemes would not recognise these areas as a specific type of wetland, nor even recognise the terrains as wetland habitat. Hill-tops are known as wetland habitats in Europe generally as part of the bog wetland assemblage (i.e., “blanket bog”), but hill-top wetlands lacking peat substrate are not as easily recognised.

The lake to river transition along the thalweg of (former) glacial valleys, such as at Luzerne and Snowdonia, is not addressed adequately by classifications. If classifications are applied at the local scale, various segments of the thalweg can be classed as “lake”, or

37 “rivers”. Nearly all classifications fail to class these systems in their totality, even though the “river-and-lake” array presents itself as a single, longitudinally contiguous network. The anthropogenic altered “lake” also is not correctly addressed. Many of the so-called “lakes” in the Swiss Alps and the Swiss Molasse foothills, for instance, naturally may have been seasonally inundated depressions, that with the construction of small dams at their down-stream constrictions became artificially permanently inundated. In this context, they are not true natural lakes, but artificial. Damming of seasonally flooded rivers creates similar results: the thalweg is transformed from a seasonally flooding channel-way to an artificial lake.

This issue of anthropogenic impact on wetlands is not adequately addressed in the nomenclature of wetlands that have been identified/classed on the bases of their vegetation. The fens in the region of the Bogs of Allen, for instance, which, in terms of vegetation, comprise heath and herbs, are founded on an anthropogenically developed surface cut into peat. They are the product of the open-cut mining of peat, their surfaces lowered by excavation nearly down to the basement sediment within which resides a minerotrophic groundwater system, so that the ombrotrophic nature of the peatland has been altered. These fens are an anthropogenically created habitat supporting a disturbance vegetation assemblage. Essentially, where fens are disturbance systems, the current classification systems based on vegetation and its water source/quality do nor reflect this condition.

The Askham Bog illustrates several problems with wetland classification. In the first instance, the vegetation formations that once colonised the area have markedly changed, but the wetland is still termed the Askham Bog. In this context, it is probable that the name now only reflects a well-known geographic identity , rather than being scientifically accurate. Secondly, the Askham Bog, as a single (formerly deep) basin, highlights a problem with use of vegetation as a system of wetland nomenclature. Different parts of the basin are inhabited by different vegetation assemblages in mosaics or as a circumferential formations (e.g., fen, forested swamp, bog), and all lend their name to the relevant small-scale local part of the wetland. Thus the whole wetland is not a bog, or a fen, or a forested swamp, but is composed of mosaics of these vegetation formations. However, what should the overall wetland entity be called? A bog, or a fen, or a forested swamp? We suggest wetland classification should be such that Askham Bog can be scientifically classified as a single entity, wherein depending on the patchiness of the soil, and the variable source and chemical quality of the water, there are differing vegetation associations developed across its surface. Thirdly, what size (or scale) must the vegetation mosaic be for it to lend its name to a given part of the wetland complex? In other words, how small or large must a patch of ombrotrophic bog be before it becomes relevant to the naming of a larger wetland complex? The last matter in Askham Bog in regard to wetland classification relates to the present quality of the water. The wetland is now a nutrient basin for sewerage disposal. Thus the ombrotrophic source of water which maintained the bog has been replaced by an (anthropogenic) minerotrophic, and effectively eutrophic source of water. This has forced changes in the vegetation, and since wetlands such as Askham Bog are classified on their vegetation

38 (reflecting nutrient status and soils), changes in this vegetation, even though anthropogenically induced, should change the classification of the wetland.

The natural history dynamics illustrated by the wetlands in the Cottonwood Lake area serve to show the problems in classification and terminology that can arise if based on vegetation. Here, wetland nomenclaturecould be rapidly changing in response to changing vegetation associations. If using a wetland classification, based on underlying determinative attributes, the wetland basins of the Cottonwood Lake area would remain classed as the same systems, regardless of the dynamics of the vegetation. Essentially, vegetation changes, which are reflecting short term changes in rainfall frequency, and secondary effects of hydrochemical changes, should not be causing short term changes in the classification of wetlands. This suggests that vegetation should not be the primary criterion for classifying a wetland.

The issue of short term fluctuations in vegetation leads on to the general problem of using any attribute that varies markedly in the short term, unless the dynamics are specifically incorporated as a category. Classifying variability in salinity or nutrients as a category of water quality, and using that term as a descriptor is an example of the latter practice. Consider the classification of invertebrate and vertebrate fauna as an example to illustrate this idea. It is important to classify invertebrate or vertebrate biota, spatially and temporally, as a index of community structure and dynamics, for comparison of biota between wetlands and as a measure of the hydrochemical and hydrological status of a given wetland. However, such information should not form the foundation of any wetland classification. For instance, nutrient content and substrate types can fundamentally determine the composition and abundance of planktonic and benthic microflora and microfauna, and macroflora, all of which in turn determine the composition and abundance of macrofauna and higher order consumers. These lower order components of the ecosystem are known to fluctuate widely in composition and abundance over the season, not only inordinately complicating classification, but also creating unstable classes.

39 5.0 A proposed hierarchical and scalar classification for natural inland wetlands

5.1 Preamble Although many wetland classification systems have been devised, used successfully, and valued for their simplicity (Mitsch & Gosselink 1986), they have been limited by the fact that often they are only applicable within the limited geographic range for which they were designed. When transferred to another physiographic or climatic region, ambiguities and omissions become apparent. The periphery of the problem lies in the number of attributes which are incorporated as primary criteria in the classification in an effort to encompass wetland diversity. Even “simple” classifications include landscape position, hydroperiod, position of water table, depth of water, water quality, plant physiognomy, and implied landform characteristics in the first or second tier. The most practical classifications are those which have consistent and few criteria at a primary level (e.g., the early wetland classification by US Fish and Wildlife Service which used Inland versus Coastal and Freshwater versus Saline categories; Mitsch & Gosselink 1986). The central problem is, however, that to date, the criteria selected for classifications have lacked universality and have not captured the full range of wetland types. When an effort has been made to surmount these problems, it has resulted in inconsistent application of criteria (Martin et al. 1953, Golet & Larson 1974, Wharton et al. 1976, Gosselink & Turner 1978, Heikurainen & Pakarinen 1982, Paijmans et al. 1985, Brinson 1993, Ramsar Convention Bureau 1998).

The attributes of wetlands which are universal are land and water. To achieve consistency and universal usage, classification criteria to be applied at the primary level of classification should ideally involve land and water characteristics, at secondary and tertiary levels, should involve further subdivision of these attributes, and at quaternary levels, include the resultants of these attributes (e.g., biota, and sediment and soil types).

Wetland scientists are faced with a large range of different types of wetlands developed across the Earth’s surface, located in various climatic regions, geological and physiographic settings, and biogeographic regions, with a variety of hydrological mechanisms that maintain them, and at the local scale, in different types of landform settings, in various sizes, and with a variety of underlying sedimentary materials and soils. Wetlands and wetland suites transcend biogeographic regions, and therefore classification, in the first instance at the core level similarly should transcend biogeographic boundaries. Similarly, although wetlands and wetland suites respond to climate setting, they also may transcend climatic regions. In order to reflect this natural order, wetland classification, while reflecting climate influences at core levels, should not be bound by climate divisions. In this context, we will first outline why landform and water, and not biota (vegetation) and soils should form the core level of classification of wetlands. We will show that using land and water characteristics there can be a systematic classification of wetlands from the site-specific level through to (megascale) wetland regions, a scalar process of classification that will not be possible using more traditional attributes at the primary level. Using second level descriptors the range of

40 wetlands can be captured regardless of climate setting, geology, physiographic setting, hydrological maintenance, soils and sediments, and biota.

The theoretical preamble presented herein rests on the premise that wetlands are essentially wet landforms and lend themselves to systematic classification initially on their landform and water characteristics. To outline the approach we adopt to classifying wetlands, we present two case studies. The first case study is a description and classification of desert dunes. Although a dry, waterless environment, paradoxically, dunes provide an excellent example to illustrate the principles of wetland classification in that the issues of landform underlying classification and the problems of the use of vegetation as a primary criterion for landscape classification are readily apparent. The second case study is a narrow belt of basin wetlands located in a sand terrain that is latitudinally extensive in southwestern Australia, spanning nearly 600 km across a climate gradient from humid to arid.

5.2 Desert dune classification Metaphorically, dunes can be viewed as the “negative wetlands”. Dunes are topographically positive features, while wetlands generally are topographically negative landscape features. Dunes are dry landscapes, while wetlands are wet. However, desert dunes provide principles of classification applicable to wetlands, and can highlight some of the problems of wetland classification. If the reader initially can accept the use of desert dunes as a surrogate for wetland classification, then later in this discussion, we will conceptually invert the topography, and in process convert dunes from topographically positive to negative features, and carry with this process the principles and style of classification from the dunes to the wetlands.

In descriptive classifications, dunes are subdivided into geometric types (McKee 1976): linear, parabolic, barchan, and star dunes (Fig. 5.1A), each formed in a specific wind environment, so that while the classification is descriptive (non-genetic), the dune type nomenclature mirrors genetic categories. Dunes can be further characterised as to their size (e.g., megascale, macroscale) to define their size and height, to their complexity (e.g., simple dunes, or complexes of dunes in sand seas), and their vegetation cover (e.g., mobile dunes versus fixed dunes), and while dunes can support distinct assemblages of vegetation and fauna, biota plays no part in their classification. In the Western Australian desert, for instance, where Triodia tussocks inhabit the crests and flanks of linear dunes, and Acacia thickets may inhabit the crests of other dunes, there is no classification such as Triodia ridges, Triodia flanks, and Acacia ridges to characterise the dunes.

If the dunes were to be topographically inverted to create linear, parabolic, barchan and star-shaped depressions, deep enough to intersect the water table, the water-filled landforms would become wetlands. In this context, we suggest that the classification style should remain the same, i.e., the basins would be classed as linear, parabolic, barchan, and star-shaped (Fig. 5.1B). The degree of wetness, e.g., permanently inundated, seasonally inundated, or seasonally waterlogged landscapes, would be used to categorise these depressions as wetland types. (Fig. 5.1B. Vegetated dunes, if inverted,

41 would become vegetated wet depressions, and the classification style, i.e., focused on the geometry of depression, should be carried over, with the adjunct that the extent of wetting be used to categorise the various depressions.

At the next scale, desert dunes often occur as assemblages, frequently forming specific dune fields or sand seas (ergs). Sand seas can be composed wholly or dominantly of star dunes, linear dunes, or parabolic dunes. These assemblages can be viewed as suites, and represent groups of dunes formed in a similar way. A repetitive field of barchan dunes, for example, will form in a specific desert environment, where there is a limited sand supply, and a rocky pavement. Elsewhere, with mixed wind directions, and abundant supply of sand, a field of star dunes may form. These aggregations of similar dune types, or if inverted for the wetland model, aggregations of similar basin types, is the foundation of the concept of “consanguineous suites” to be discussed later.

5.3 A climatically extensive set of wetland basins on a sand terrain In southwestern Australia, there is a system of relict dunes, comprising an undulating terrain (hills and basins), underlain by quartz sand, that forms a narrow (10-20 km wide), but longitudinally extensive landform unit called the Bassendean Dunes within the Swan Coastal Plain (McArthur & Bettenay 1960). The template of basins and hills, inherited as a landform from the arid Pleistocene, is the consistent and common small-scale geomorphic characteristic of this system The basins commonly intersect the regional water table, resulting a series of wetlands. Depending on the extent and depth that the groundwater system is intersected, these basins may be permanently inundated, seasonally inundated, or seasonally waterlogged (Semeniuk 1988). In this discussion, we will concentrate on the deeper basins that support hygrophilic vegetation.

Extending some 600 km from south to north, the narrow belt of relict sand dunes today is located in a humid climate in the south, through subhumid and semi-arid climates in central portions, and in an arid climate to the north. As a result, the basins support different wetland vegetation and have developed variable sedimentary fills: to the south, the basins have accumulated peat under sedges; vegetatively, they support mixed paperbark trees and sedges that cover the whole wetland; to the north, they have accumulated diatomite, and support vegetation of paperbark trees confined to the basin margins (Fig. 5.2). The transition from southern types to northern types is not sharp, but gradational, such that, apart from those basins located at the latitudinal extremes, it is difficult to separate and classify the various wetlands along the longitudinal belt wholly on vegetational or sedimentary characteristics. While the wetlands essentially are the same type of basins located in different climates, if concentrating on vegetation, each wetland could/would be classified differently, and if soils and vegetation formed the core of a wetland classification, again, the wetlands to the south could/would be classified differently from those to the north. Yet, the underlying template of all the wetlands is the same - they are basins in a quartz sand dune terrain, with the depressions intersecting the water table. It is largely the climatic setting that underpins the different vegetation associations and the different sedimentary fills across the latitudinal spread of these wetlands. We reason that a classification in the first instance should be based on primary

42 features of a wetland, and not initially, reflect climate, and in the case of wetlands within the relict dune terrain, all the wetland basins in this example should be termed similarly, with the latitudinal/climatic differences brought out with descriptors.

5.4 Scalar approach Scale is important in structuring any classification system especially when the primary targets of the classification range in size and/or occur in larger aggregations or clusters of the primary units (Fig. 5.3). In relationship to inland wetlands, scale is applied to classification in two ways. Firstly, at the site-specific scale of individual wetlands, as a descriptor, using a fixed, defined frame of reference as a quadrat to categorise the size of a given wetland. Secondly, at the scale at which wetland systems are viewed in their structural setting, and in this context there are up to four scales of observation: (1) the site-specific level, (2) that of aggregations of wetlands into natural suites, and (3) that of subregion and region containing a repetitive geologic, geomorphic, climatic, and hydrologic pattern. These scalar concepts are illustrated in Fig. 5.4.

5.4.1 Use of scale to define size of site-specific individual wetlands For site specific wetlands, the following scale of observation, or fixed frames, modified from C A Semeniuk (1987), are employed for wetland basins and plains that have a tendency to be equant in plan view (Fig. 5.5A):

Frames of reference for wetland basins and plains megascale > 10 km x 10 km macroscale 10 km x 10 km to 1 km x 1 km mesoscale 1000 m x 1000 m to 100 m x 100 m microscale 100 m x 100 km to 10 m x 10 m leptoscale < 10 m x 10 m

For site specific wetlands, the following scale of observation, or fixed frames, modified from C A Semeniuk (1987), are employed for wetland channels that have a tendency to be linear (narrow and long) in plan view (Fig. 5.5B):

Frames of reference for channels macroscale > 1000 m wide, tens to hundreds of kilometres long mesoscale 100s of metres wide, tens of kilometres long microscale 10s of metres wide, tens to several kilometres long leptoscale several metres wide or less, several/tens of kilometres long

43 5.4.2 Scalar approach to delineate aggregations of wetlands and their patterning There are no fixed, defined scales of reference for the aggregations of suites of naturally occurring wetlands, nor for the wetland regions because the three determining factors in both are 1. the wetland types which are present, 2. the pattern of distribution and array of the wetlands, and 3. the landscape, geology and hydrology host to the wetlands. But the scale encompassing the aggregations of natural wetland suites is larger than that of the site specific wetlands that comprise it, and the aggregations of natural wetland suites within a region are smaller than the wetland region. Thus there is an ordinal, though elastic change in scale of observation (Fig. 5.6).

The four scales of observations are named herein as follows:

1. the site-specific level = individual wetlands 2. aggregations of wetlands into natural suites = consanguineous suite 3. a subregion containing a repetitive geologic, geomorphic, = wetland subregion climatic, and hydrologic pattern and underpinning of wetlands 4. a region containing a repetitive geologic, geomorphic, = wetland region climatic, and hydrologic pattern and underpinning of wetlands

These terms derive from Semeniuk (1988), viz., “consanguineous suite”, and V & C Semeniuk Research Group (1999, 2000), viz., “wetland subregion” and “wetland region”. Note should be taken that for some areas, with relatively simple array of landscapes, there may be only three scales of patterning, viz., individual wetlands, “consanguineous suite”, and “wetland regions”, without development of “subregions”.

To illustrate the principles and practicalities underlying the delineation of the aggregations of wetlands and their patterning into suites,. an example of wetland systems is provided below, drawn from the Swan Coastal Plain, south Western Australia. This Coastal Plain exhibits an array of wetland basins, channels and flats (plains) (Fig. 5.7). The Plain comprises four main landscape belts (“geomorphic units” of McArthur & Bettenay 1960), underlain by Holocene to Pleistocene coastal sand, limestone, desert dune sand, and alluvial sediments, oriented north-south in shore-parallel systems. Within each “geomorphic unit” there are specific suites of wetlands, with various types of basins in central to coastal parts of the Plain, and basins, channels and flats in eastern inland parts of the Plain (Semeniuk 1988). These wetlands have specific size, shape, soils, and origin, depending on their setting, e.g., within the youngest geomorphic unit, the Holocene coastal dunes, there are three suites of wetlands formally named by Semeniuk (1988): the Becher Suite, comprising linear chains of small wetlands in beachridge interdune depressions, the Peelhurst Suite comprising wetlands in dune blow-outs, and the Cooloongup Suite comprising former marine basins cut off by a barrier spit (Fig. 5.8). A summary of the wetlands on the Swan Coastal Plain, and characteristics of the various scales, is presented in the Table below, with selection of subregions, consanguineous suites and site-specific wetlands focused on the wetland within the coastal dunes.

44

Scale of reference Description Wetland Region = Swan Coastal Plain Swan Coastal Plain (McArthur & relatively low to moderate relief coastal plain, 600 km long, Bettenay 1960) 20-30 km wide, north-south oriented, shore-parallel units composed of belts of coastal sand, limestone and sand, and desert sand, and to the east, alluvial plains; a shallow regional water table creates many of the wetlands Wetland subregion = individual geomorphic units of the Swan Coastal Plain subregion coastal dunes = Quindalup relatively low to moderate relief coastal dune system, 600 Dunes (McArthur & Bettenay 1960; km long, < 100 m wide to 10 km wide, north-south oriented, Semeniuk et al. 1989) shore-parallel unit composed of coastal sand; three types of wetland suites therein subregion limestone belt = Spearwood moderate relief former coastal dune system, 600 km long, ~ Dunes (McArthur & Bettenay 1960; 5 km wide, north-south oriented, shore-parallel unit Semeniuk & Glassford 1989) composed of limestone and sand; several types of wetland suites therein subregion desert dune sand = low to moderate relief former desert dune system, 600 km Bassendean Dunes (McArthur & long, ~ 5 to 10 km wide, north-south oriented, shore-parallel Bettenay 1960; Semeniuk & Glassford unit composed of quartz sand; several types of wetland suites 1989) therein subregion alluvial sediment = Pinjarra low relief alluvial plains and former desert dune system, 600 Plain (McArthur & Bettenay 1960) km long, ~ 5 to 10 km wide, north-south oriented, shore- parallel unit composed of quartz sand; several types of wetland suites therein Consanguineous wetland suite = aggregate of similar wetlands within a given geomorphic unit Becher Suite (Semeniuk 1988) linear to ovoid small wetlands, often in chains, located in interdunal depressions (swales) of the beachridge systems of the coastal dunes; comprising seasonally inundated and seasonally waterlogged freshwater basins Peelhurst Suite (Semeniuk 1988) irregular to ovoid small wetlands, in bowls of dune blow- outs of the beachridge systems of the coastal dunes; comprising seasonally inundated and seasonally waterlogged freshwater basins Cooloongup Suite (Semeniuk 1988) round to ovoid large wetlands, formed by cut-off of marine waters by a spit or low barrier; comprising permanently inundated to seasonally inundated freshwater basins Site specific wetland within the Becher Suite (Semeniuk 2004) Wetland type 1: linear-ovoid, small wetland, seasonally inundated, underlain by carbonate mud Wetland type 2: linear-ovoid, small wetland, seasonally inundated, underlain by peat and carbonate mud Wetland type 3: linear-ovoid, small wetland, seasonally waterlogged, underlain by carbonate muddy sand

We have obtained similar results in delineating aggregations of wetlands into consanguineous suites, wetland subregions, and wetland regions throughout Western

45 Australia: D’Entrecasteaux Coast region, the Yilgarn Plateau, the Great Sandy Desert, the Pilbara region, the Gibson Desert, the Simpson Desert, and the Nullarbor Plains; and elsewhere in the world: the Natal region in southern Africa, the Canadian Shield, Ireland, France and the Swiss-Italian Alps.

This approach to delineating wetland systems by a scalar approach is not the same as that employed by landscape scientists who define landscape units where, the focus is on all landforms in a given area in terms of their shapes and aggregations in increasing size (Mitchell 1973). For individual wetlands and suites, the focus is narrowed to patterns within the topographic depressions. The encompassing regional landscape thus is not the focus in the approach here, but only forms the template for the wetlands, though for classification of subregion and region there is increasing overlap. The term “wetland region” is used for the largest scale of patterning, and not in the sense of “land region” used by landscape system scientists (for the range of surface forms and properties expressive of rock unit or close association of rock units having everywhere undergone comparable geomorphic evolution, and occurring in areas with map scales of 1:1,000,000 to 1:5,000,000; see Mitchell, 1973). The smaller scale terms of “site-specific”, individual wetland”, consanguineous suite” and subregion” have no equivalent in landscape terminology.

The idea of recognising wetland patterning in increasing scale within “wetland consanguineous suites”, “wetland subregions”, and “wetland regions” partly overlaps with the idea of “catchment”, wherein wetlands are aggregated into drainage related groups. However, “catchment”, implies that wetland patterning is strongly linked to actual drainage lines. The Swan Coastal Plain examples described above, together with the wetland patterning in the Great Sandy Desert and the Nullarbor Plains, for instance, do not accord with the “catchment approach”, and although the Pilbara Region is drainage dominated, its also does not lend itself to the categorisation of wetland patterning using the “catchment” approach. “Catchment”, however, will be discussed again later.

5.5 Philosophy of approach in classification: determinants and descriptors Climate ultimately drives the development of wetlands in that it influences the development of landforms, the amount of rainfall and evaporation, and the biota. Firstly, it plays a role in determining the type of landforms developed for a given geological region through weathering and erosion, though it must work on the primary geological materials at a given site. Climate also determines the amount of rainfall and evaporation that occurs in a given region and so controls the delivery of water, its recharge, hydroperiod and the evolution of hydrochemistry over the seasons. It also plays a role in determining the occurrence and types of biota, which influence development of wetland soils (e.g., peat versus diatomite versus evaporite), and the extent that soil development is sustained. While climate affects many aspects of wetland development and function, and is inter-related to geomorphology, water, soils, and biota in a given wetland system, climate is not a primary determinant of wetlands.

46 At the scale of individual wetlands, the primary determinants in the development of wetland types regardless of climatic setting are land and water. Land determines the size, shape and depth of the water of the wetland, and to some extent the nature of the stratigraphy and soils that fill or develop on the wetland. Aspects of water determine hydrological maintenance of the wetland (in terms of meteoric recharge, artesian delivery, run-off, groundwater table rise), its hydroperiod and hydrochemistry. Soil types and stratigraphic fills within wetlands are a secondary or even tertiary response to landscape setting, biota, hydroperiod and hydrochemistry. Vegetation in a given climatic setting is a secondary or tertiary response to soils, hydroperiod, and hydrochemistry. Hydrochemistry is a secondary response to water sources, transpiration, cation usage by vegetation, and evaporation.

Hence to begin with, we concentrate on land and water as the main determinants of wetland within a given climatic setting. Various landscapes determine the various types of wetland as basins, flats and channels, etc., and various hydroperiods determine the extent to which that the landscape is inundated or wetted. Landscape and its subdivisions, and water and its various hydroperiods thus provide the characteristics for delineating the primary wetland types. Other aspects of landscape, such as its size, shape, stratigraphy and soils, provide criteria for further subdivisions that can categorise primary wetland types at secondary and tertiary levels. Other aspects of water such as salinity, hydrochemistry, hydrochemical evolution, and source provide criteria for further subdivisions that can categorise primary wetland types from the water perspective at secondary and tertiary levels. Biota, influenced by soils, hydroperiod regime, and hydrochemistry are tertiary responses to a wetland setting.

5.6 The proposed classification: at the site specific scale Our approach to categorisation of wetlands initially is to identify non-emergent wetlands that reside in the landscape, and self-emergent wetlands that through vertical accretion of sedimentary materials or chemical and/or biogenic accumulation have emerged beyond the original land surface developing a new convex wetland geomorphology (Fig. 1.3).

5.6.1 Non-emergent wetlands For non-emergent wetlands that are terrain conforming, at a primary level, it is landscape settings that are host to wetlands, and hydroperiod regimes that define and maintain wetlands. The initial subdivision of landscape types host to wetlands based on and designed for the region of the Swan Coastal Plain by Semeniuk (1987), viz., basins, channels, flats, and those additional landscapes identified by Semeniuk & Semeniuk (1995), viz., slopes and hill-tops, have now been expanded to six main landscape settings that are host to wetlands, viz., basins, channels, vales, flats, slopes and hill-tops. And further to the initial subdivision of hydroperiod regimes based on and designed for the region of the Swan Coastal Plain by Semeniuk (1987), viz., permanently inundated, seasonally inundated, seasonally waterlogged, and the additional regime used by Semeniuk & Semeniuk (1995), viz., intermittently inundated, we now recognise five main water regimes and hydroperiods that maintain wetlands, viz., permanently inundated,

47 seasonally inundated, intermittently inundated, seasonally waterlogged, and permanently waterlogged.

Definition of the terms for landscape and water regime are provided in the Table below.

Terms for landscape and Description/definition water regime or hydroperiod Landscape term basin contained, closed depression in the landscape channel linear, open relatively narrow depression in the landscape vale linear, open relatively broad depression in the landscape flat (or plain) flat or slightly undulating terrain slope sloping surface hill-top convex upper surface of landscape Water regime or hydroperiod term permanently inundated water present above surface permanently, though its level may fluctuate seasonally inundated water present above surface on a seasonal basis intermittently inundated water present above surface intermittently, say every 5 years permanently waterlogged water wetting the surface on a permanent basis seasonally waterlogged water wetting the surface on a seasonal basis

If a wetland is seasonally inundated, it may also be permanently waterlogged, however, the former presides over the latter hydrological state. Combining these in a matrix structure results in various categories of wetlands defined on landscape type and water regime (or hydroperiod). Some of the categories are axiomatically not possible (e.g., permanently inundated hill-tops, or slopes), and so focusing on actual wet terrain that is realistic, there are 19 primary categories of wetlands, as follows:

Water regime or hydroperiod permanent seasonal intermittent seasonal permanent inundation inundation inundation waterlogging waterlogging Landscape type basin WETLAND WETLAND WETLAND WETLAND WETLAND channel WETLAND WETLAND WETLAND WETLAND vale WETLAND WETLAND flat (or plain) WETLAND WETLAND WETLAND WETLAND slope WETLAND WETLAND hill-top WETLAND WETLAND

The wetland categories are non-genetic. Information on source of water or maintenance of the water regime (e.g., surface run-in, rainfall, water table rise, perching, or artesian upwelling), while important to know and determine, have no part in its classification at a primary level, and should be used as descriptors delineating different type of wetlands at

48 tertiary or quaternary levels; similarly, origin of landform has no place the primary level in the classification (see Semeniuk 1987, and Semeniuk & Semeniuk 1995, for more detailed discussion).

The natural categories Tabled above, rather than being named Type A, Type B, Type C, etc., require nomenclature, and our approach has been to use existing terms, if appropriate. Terms for nomenclature should satisfy two criteria: they must be single words (e.g., sumpland), rather than two words or multiples of words (e.g., “seasonally inundated basin”), and preferably, if newly coined, the core attributes of the term should be deducible by its deconstruction (e.g., palusmont, a type of wetland whose etymology derives from palus and mont, both Latin words, meaning wet and marshy, and hill-top, respectively).

Terms have already been employed to name some of the wetland categories, derived from existing terms (e.g., lake, and floodplain), and some had been coined by Semeniuk (1987) and Semeniuk & Semeniuk (1995). New terms are required for the now additionally recognised categories of seasonally waterlogged and permanently waterlogged vales, and the permanently waterlogged landscapes. Also, while in the past we have used the term “playa” to denote an intermittently flooded basin, we have since concluded that “playa” is inappropriate because of its long term usage in meaning in Australia, its variety of meaning across the world, and its etymology. We therefore propose the term “pirapi”, an indigenous word from the desert regions of Western Australia referring to the intermittently flooded basins that often are saline. The indigenous peoples of the arid regions in having to survive in largely waterless desert environments for thousands of years have categorised wet environments for practical purposes and commonly and provide appropriate terms that encapsulate wetlands in terms of their permanence, intermittence, and behaviour such as flow, upwelling, and connection to groundwater.

Water regime or hydroperiod permanent seasonal intermittent seasonal permanent inundation inundation inundation waterlogging waterlogging Landscape basin LAKE1 SUMPLAND2 PIRAPI4 DAMPLAND2 BASINMIRE5 channel RIVER1 CREEK1 WADI1 TROUGH1 vale PALUSVALE5 VALEMIRE5 flat (or FLOODPLAIN1 BARLKARRA PALUSPLAIN2 FLATMIRE5 plain) 4 slope PALUSLOPE3 SLOPEMIRE 5 hill-top PALUSMONT3 MONTMIRE5

1. existing terms adapted for wetland terminology 2. term coined by Semeniuk (1987) 3. coined termed by Semeniuk & Semeniuk (1995) 4. terms adopted from the Indigenous peoples of the region for that type of wetland 5. term coined in this document

49

The term “mire” is well established globally to designate permanently waterlogged areas, and we use this term in conjunction with landscape type to denote the various types of permanently waterlogged terrains. Thus the suffix “mire” in the terminology consistently denotes permanent waterlogging, and the prefix denotes the landscape setting of the permanently waterlogged environment. Where terms had been coined by Semeniuk (1987) and Semeniuk & Semeniuk (1995) for seasonally waterlogged terrains, and in this document for seasonally waterlogged vales, the prefix “palus” consistently has been used for the regime of seasonal waterlogging (except for the waterlogged basins).

Thus, embedded in the single word terms are the attributes of landform shape and hydrologic regime, to which various descriptors can be added. For example, the term “sumpland” carries within the word the attributes of being a “basin that is seasonally inundated”, the term “dampland” carries within the word the attributes of being a “basin that is seasonally waterlogged, and term “floodplain” carries within the word the attributes of being a “flat that is seasonally inundated”. Adding the adjectival descriptors will separate, for instance, megascale, round, saline sumplands from microscale, irregular, freshwater sumplands.

Descriptors for the primary wetland units are discussed in the sections under land descriptors, water descriptors, and vegetation descriptors.

In the style of diagrams presented for the boundaries of wetland basins, Fig. 5.9 illustrates the hydrological features and boundaries of five basin wetlands that have the basic five water regimes.

5.6.2 Self-emergent wetlands As noted earlier, self-emergent wetlands are those that have accreted sedimentary, chemical and/or biogenic materials and have emerged beyond their original geomorphic surface to develop a new wetland landscape through the complete filling of a lowland and the development of a convex surface (Fig. 1.3). The term self-emergent should not be confused with the term “emergent wetland” such as used by Cowardin et al. (1979) to refer to the vegetation within a wetland which extends above the level of the water. In our usage, “self-emergence” means that the wetland deposits have sufficiently accreted to emerge largely above the level of the host terrain to form a convex surface, thus promoting the development of a newly emerging terrain by wetland accretionary processes.

Self-emergent wetlands are often termed mounds, e.g., mound springs. Raised bogs that have become convex, self-emergent wetland systems are mounded accumulations of peat. We recognise several types of self-emergent wetlands, base on their accretionary material. They occur in a wide variety of settings, ranging from sites of freshwater artesian upwellings in arid environments, to rapid accumulation of plant matter under sustained rainfall conditions, to precipitation forced by evaporation, and mineral-charged volcanic source water. If undifferentiated as to accreting materials, we suggest these

50 wetlands be named “wetland mounds”. Previous terms for some of the mounded deposits are “mound springs” for accumulations of minerals, “raised bogs” for mounded peat deposits formed by Sphagnum mosses sustained ombrotrophically, “peat mound” for convex deposits of peat, and “sinter mounds” for accumulations of silica at fumeroles associated with emerging magmatic waters. We have used some of these terms previously (Semeniuk & Semeniuk 1995), but suggest now that terms for wetland mounds be made uniform in that the material comprising the mound be the adjectival descriptor for the mound.

The range of mounded self-emergent wetlands, based on accreted materials, we have documented to date, is as follows:

1. peat mounds 2. carbonate mounds 3. diatomite mounds 4. sinter mounds 5. gypsite mounds

Description, hydrological maintenance processes, and some examples of wetland mounds is provided in the Table below. Note that while the hydrological maintenance processes are described below, they are not criteria for the primary subdivision of type of wetland mounds - the description is provide to illustrate the variety of hydrological mechanisms that can result in mounding.

Wetland mound Description Examples type peat mounds mounded accumulation of peat, Bogs of Allan, Ireland; Foxtor Mire sustained by rainfall, or artesian in the UK, Cranesmoor in the UK; upwelling, or seepage peat mounds of the northern Great Sandy Desert, Western Australia carbonate mounds mounded deposit of calcite, mound springs of the Simpson precipitated from mineral Desert South Australia; mound charged waters often by artesian springs of the Burgundy region in upwelling, or seepage France; mound springs of the eastern Swan Coastal Plain, SW Australia diatomite mounds mounded accumulation of wetland mounds of the central diatoms, with populations Great Sandy Desert, Western sustained by artesian upwelling, Australia or seepage sinter mounds mounded deposit of accreted sinter mounds around the volcanic crystalline silica (as distinct from terrain of the north island of New diatoms, which are amorphous Zealand silica), precipitated from mineral charged waters often by artesian upwelling, or seepage, or

51 magmatic fumeroles gypsite mounds mounded deposit of gypsum, gypsite mounds of the wetland which has precipitated by basins of Peron Peninsula, Shark evaporation from mineral Bay, Western Australia charged shallow groundwaters, with ongoing precipitation forcing lateral and vertical expansion leading to mounding

Descriptors for wetland mounds are discussed in the next section.

5.6.3 Descriptors of landscape The landscape/landform attributes useful as descriptors for refining the various wetland categories are as follows: size of wetland, shape of wetland, type of soils, type of stratigraphic fill, and extent of landscape filling by stratigraphic fill or accretion of materials. These descriptors are outlined in the Table below, and illustrated in Fig. 5.10.

Landscape/landform attribute Subdivision of attribute for use as descriptor size for basins, flats, slopes, hill-tops megascale, macroscale, mesoscale, microscale size for channels and vales macroscale, mesoscale, microscale, leptoscale shapes for basins, flats, slopes, hill- round, ovoid, linear, irregular, equant tops shapes for channels and vales straight, meandering, braided soils peat, quartz sand, carbonate sand, carbonate mud, diatomite, terrigenous mud, soda mud, gypsite, halite stratigraphy peat-dominated, quartz sand-dominated, carbonate sand- dominated, carbonate mud-dominated, diatomite- dominated, terrigenous mud-dominated, soda mud- dominated, gypsite-dominated, halite-dominated, or mixed, or in layers extent of stratigraphic filling of unfilled, thinly filled, thickly filled (see Fig. 1.3) landform landscape setting for wetland basin-filled, valley tract or channel, vale, plain, slope, mounds hill-top

Examples of the use of these descriptors is provided below. Consider a wetland basin that is seasonally inundated, i.e., a sumpland. Use of the size descriptors will readily differentiate, for instance, between megascale sumplands, macroscale sumplands, and microscale sumplands. Use of shape, and soil descriptors will further differentiate the various types of sumpland. Consider these examples:

megascale, round, peaty sumpland megascale, irregular, peaty sumpland megascale, round, gypseous sumpland

52 macroscale, round, peaty sumpland microscale, round, quartzose sandy sumpland microscale, linear, carbonate mud sumpland

The progressive filling of lowlands such as basins, vales, channels and flats by peat can grade from thinly to thickly filled, eventually developing into raised bogs (Fig. 1.3). Other basins, though more rarely, may similarly accumulate diatomite, or gypsite, or carbonate precipitates. If the information is available, the extent that the landscape is stratigraphically filled can be used as a descriptor, and the landscape setting of a wetland mound may be used as a descriptor.

5.6.4 Descriptors of water The water and hydrological attributes useful as descriptors for refining the various wetland categories are as follows: salinity, consistency of salinity, opacity and colour, other specific hydrochemical characteristics, water source, water maintenance, depth, rate of movement. The period of freezing in wetlands as part of the seasonal cycle is addressed in the descriptors as well. The descriptors for water are outlined in the Table below, and illustrated in Fig. 5.10.

Water/hydrologic Subdivision of attribute for use as descriptor attribute salinity consistency of salinity poikilohaline, stasohaline (Semeniuk 1987) opacity and colour clear water, black water (tannin stained), white water, etc. other specific nutrient-enriched, or with subdivisions (oligotrophic, mesotrophic, hydrochemical eutrophic) characteristics water source ombrotrophic, meteoric, minerotrophic, artesian, magmatic water maintenance meteoric, groundwater, artesian, surface run-off depth shallow (< 1m), moderately deep (1-2 m), deep (2-10 m), very deep (> 10 m) rate of movement very slow moving or static (lentic); fast moving (lotic) water freezes for part of if seasonally frozen add descriptor “cryoperiodic”; if not frozen, year no descriptor required

Examples of the use of these descriptors is provided for a wetland basin that is a sumpland: use of the salinity descriptors will readily differentiate, for instance, between a freshwater stasosaline sumpland, a freshwater poikilohaline sumpland, a poikilohaline saline sumpland, and a stasosaline saline sumpland. These categories will have follow-on implications for the type of biota resident or visiting the wetland. Use of the other water attributes as descriptors will further differentiate the various types of sumpland.

5.6.5 Descriptors of vegetation

53 Vegetation forms an important part of the wetland ecologically and in terms of generation of sedimentary fill and soil types, and wetlands can be characterised by the form and pattern of the vegetation that inhabits them. Semeniuk et al. (1990) designed a classification scheme for systematically classifying wetland vegetation based on the extent of cover, and its internal organisation, e.g., zoned, mottled, or homogeneous, and this scheme is presented in Figure 5.11. The nine terms generated by the classification scheme can be used as descriptors to characterise a wetland vegetationally at the organisational level. Further refinement of the vegetation beyond extent of cover and its internal organisation can be achieved by use of life forms present, and outlining the zonation within the wetland as suggested in Figure 5.12 (from Semeniuk et al. 1990).

5.7 Problems in classifying wetlands geomorphically and hydrologiocally In our experience, there are some problems in classifying wetlands using the scheme outlined above, and these relate to designating a landscape to a particular landform category, the merging of wetlands, the intergradation of wetlands, and the types and continuum of hydroperiod. As the classification scheme outlined above is based on landscape geometry and hydroperiods, if these have gradational boundaries between the classes, there will be problems in assigning a term to a given landscape, or assigning a term to a given hydroperiod, e.g., basins can grade into plains, slopes grade into becoming plains, and river channels can grade into becoming lakes. In our experience, however, most landforms can be easily assigned to one category or another, but if the landscape is truly on the border between two types, then the term may have to be hyphenated, and the wetland category also hyphenated to convey that it has the characteristics between two wetland classes. The same problem applies to the water regime and hydroperiod. Semeniuk & Semeniuk (1995) argue for simplifying the various categories of water regime into a few, so that classification becomes practical without reflecting every nuance of natural variation at the primary level, and in this document we continue with this theme, presenting a simplified case of 5 water regimes, with the caveat that some hydroperiods may be difficult to define. The objective of the classification, however, is to provide broad classes of categories at the primary level, and leave it to the descriptors to delineate details required to differentiate wetlands whose hydrological regime or functions are intergradational.

The issue of merging wetlands has been addressed in Semeniuk et al. (1990), and has been discussed in Section 1.0 of this document.

5.8 Temporal changes Wetlands may change in time, and in any classification of wetlands, their dynamic nature also may need to be addressed. Changes may occur in response to natural and anthropogenic influences. Climatic change, for instance, is the most important natural cyclic phenomenon and determines both short and longer term responses of wetlands. These responses are effected through changes in hydrological, and sedimentological patterns, hydrochemical characteristics, and ecological and biological responses.

54 Climatic change thus can alter the most fundamental aspects of a wetland, i.e., its boundaries, hydroperiod, depth, water quality, water permanence and function.

There are a number of natural climate cycles that can drive wetland functioning and responses, e.g., short term cycles of varying rainfall over approximately 20 years, or 250 years (Semeniuk 1995). The response of wetland hydrology to these variations in rainfall patterns, may require adjustment to the classification subsequent to the natural lag process. It should be noted, however, that any classification based on water regime would be simplified by the concept of prevailing condition (Semeniuk 1987).

5.9 The proposed classification: at the scale of naturally occurring groups - consanguineous suites The aggregations of wetlands into natural groupings based on their similarity, their common origin (even if expressed as different wetlands), or their location along a single valley tract, or along a discharge zone, was formalised by Semeniuk (1988) into the idea of consanguineous wetland suites. Being expressions of a wet, water-saturated, or inundated landscape, wetlands often exhibit repetitive clusters or aggregations, reflecting the landscape that they reside in. Global examples of repetitive landscape patterns leading to repetitive wetland patterns include the hills-and-basins system of the prairie terrain of northeastern USA, the linear dunes and interdune depressions of the Great Sandy Desert, the sinkholes exposing the water table on the Nullarbor Plain in arid southern Australia, or the glacial lakes of Snowdonia, in the UK. In these situations, with the widespread patterning in the landscape, basins are recurring in the same style, size and types. In spite of a variation in the individual basins from permanently to seasonally inundated or seasonally waterlogged, and gradation in shape and size, the reasons why the wetlands are there in the first place, i.e., the similarity of underlying processes that created them, and the continuum of landscape and water at a given site, are the bases of the concept that there are consanguineous suites. For instance, the terrain of linear dunes and interdune depressions creates a repetitive pattern of linear to ovoid basins, whose floor at times is close to or below the regional water table. The karst processes on the Nullarbor Plain create dolines and sinkholes as windows to the water table resulting in a widespread repetitive array of lakes and sumplands scattered across the region. The glacial periods in the Snowdonia region created a series of glacially excavated large and deep basins, and today these are sustained by rainfall and run-off to form lakes arrayed in a configuration reflecting the original gouging by a radiating pattern of glaciers.

However, consanguineous suites need not be solely composed of repetitive patterns of wetlands. A common underlying process can also generate a range of wetlands in response to an underlying causative factor. For instance, large scale seepage from the margin of a large dune system where it adjoins a plain can deliver water to a range of landscapes, from alluvial plains to dune margins, to dune basins, generating palusplains, paluslopes, sumplands and damplands, all sustained by the same seepage. Another type of suite is illustrated by the range of wet landforms in a fluvial setting: this may comprise river channels, floodplains, palusplains, local small sumplands, and lakes (as billabongs or oxbow lakes) that occur along a valley tract. In this situation, the wetlands and the

55 fluvial processes along the same valley tract have resulted in a variety of different types of individual wetlands at the site specific level, but an inter-related suite with a common origin at the larger scale. The Okavango inland delta in Africa serves as a megascale example of this latter situation.

It is in this context of consanguineous suites that catchment drainage basins should be viewed. Within a given drainage basin, there are rivers, creeks, lakes, sumplands, floodplains, and palusplains, forming a suite of wetlands inter-related by a common causality - fluvial discharge and sedimentation. Rivers grading to lakes along their length are captured as a natural temporally and spatially intergrading group at the consanguineous suite level.

Criteria for recognising consanguineous suites are provided in the Table below. Typical patterns of wetlands comprising consanguineous suites are shown in Figure 5.13.

Criteria for recognising consanguineous suites (from Semeniuk 1988):

1. occurrence of wetlands in reasonable proximity to each other, although proximity alone may be no indication of wetland relationship as other factors such as geomorphic processes and hydrologic regime may become significant (Fig. 5.13 A, B, D)

2. a similarity of wetland size and shape (Fig. 5.13 A)

3A. recurring pattern of similar wetland forms, i.e., a single wetland type predominates, or an assemblage of wetland types predominate (Fig. 5.13 A, B, C)

3B. heterogeneous pattern representing a spectral range of inter-related wetland forms, or association of dissimilar but genetically related wetlands; these could result where there are similar underlying causative factors, e.g., fluvial or hydrological processes (Fig. 5.13 C, E)

4. similar stratigraphy, an hence similar developmental history

5. similarity of water salinity and its dynamics

6. similarity of hydrological dynamics (e.g., whether wetlands are recharged and maintained by ponding, seepage, surface run-off, groundwater rise (Fig. 5.13 F)

7. similar origin, e.g., karstification.

56

Consanguineous suites require nomenclature, but while there are criteria to assist in the identification of consanguineous suites, there is no fixed rule for their nomenclature aside from the fact that they should draw their name from where they are best or typically developed. In this context, nomenclature should follow the same protocol as the naming of landscape units. Semeniuk (1988) formally named sets of consanguineous suites according to the geographic location where there were best developed. Thus, for instance, a distinctive suite of interdunal linear to ovoid basins ranging from sumplands to damplands occurring on a Holocene beachridge plain, underlain by quartz sand, and naturally forming a group best developed near Point Becher in southwestern Australia were termed the Becher Suite. Another distinctive group of nearly merging, individually irregular (mainly) sumplands, with some lakes and damplands, occurring in star dune terrain, and underlain by quartz sand, are best developed at Jandakot in southwestern Australia, and were termed the Jandakot Suite. While residing in their type locations, representative occurrences of both the Becher Suite and Jandakot Suite also can be found as outliers in areas within the region but outside of the type locations.

The scale of a consanguineous suite can be variable: it can be as small as 100 ha, but can range up to areas of tens of square kilometres in size. In addition, a consanguineous suite can recur throughout a region in domains, i.e., while it may have a type location, there can be occurrences of the pattern outside the type location.

5.10 The proposed classification: at the largest scale of subregions and regions Viewed at the megascale, the land often shows a recurring pattern of geology, forms, and hydrology in a given climatic setting mirrored by the repetitive pattern of wetland types and wetland style therein, producing a recognisable region-wide wetland pattern. Examples include the lakes and associated wetlands evident on the Canadian Shield, the linear wetlands of the Pilbara, and the meandering wetlands (termed colloquially “salt lakes”) of the Yilgarn Plateau in central western Australia. Though at the smaller scales, there are diverse consanguineous wetland suites, and potential variability of individual wetland types, the repetition of landscape and wetland patterns at the largest scale often is striking. This leads to the notion of classifying regional landscapes at the largest scale into regions and subregions.

A wetland region is usually a few to several hundreds of kilometres across, and has geological, physiographic, climatic and set of hydrological attributes that separate it from adjoining regions. As a consequence of these characteristics, a distinct groups of wetlands are developed. Essentially there are repetitions of the consanguineous suites described above occurring with the subregion or region.

Similar to the nomenclature of the consanguineous suites, while there are criteria to assist in the identification of wetland subregions and wetland regions, there is no fixed rule for their nomenclature aside from the fact that they should draw their name from the name of the region itself.

57

5.11 Discussion and conclusions Although rarely expressed, there are entrenched attitudes by different sectors of the scientific community with regard to classification, which impede the adoption of any global methodology. Wetlands are viewed as either biologic systems or physical entities, a perspective which eventually undermines any classification system by excluding or under emphasising one set of attributes at the expense of the other. This is most succinctly expressed in a paper by Edgar et al. (2000) which says:

“Ecosystem classifications based solely on physico-chemical data should be considered meaningless unless validated using biological information...... ”

To encompass wetland diversity, the diversity of wetland types, processes, and physical and biological attributes need to be addressed. A global classification system for wetlands needs to be inclusive rather than exclusive. From the Tables presented earlier, it can be seen that there is a systematic order in which wetland attributes should be addressed. At the primary or starting level, (i.e., site specific), we suggest that a geomorphic classification could be applied as these attributes are universal and few in number. Basins, flats, channels, slopes, hills, are not difficult to recognise in different climatic zones or geological provinces.

A scalar framework prevents the problem of comparison between site specific and regional descriptions and studies. A clear framework also facilitates the use of consistent criteria and logical progression of primary to secondary criteria, eliminating jumps from one attribute to another. Classifications which begin with some characteristic of vegetation followed by some aspect of geomorphology, followed by a return to a different aspect of vegetation, may conform to a scalar framework, but do not follow a systematic or logical progression. Cross-over of scales from level to level rather than a linear decrease or increase is also not recommended. The geomorphic classification of Semeniuk (1987) demonstrates the logic progression from one layer to another. It begins with water and land attributes at the primary level. At the next level the water is subdivided into water salinity and water maintenance. Land is subdivided into stratigraphy and planar geometry. When vegetation is incorporated it is as a single comprehensive feature incorporating pattern, cover, structure and composition.

Many wetlands have been viewed as separate entities and classification has aimed to demonstrate their biodiversity. At larger scales, the scientist must separate attributes, which make every wetland habitat unique, from those attributes which facilitate recognition of groups of wetlands. Apart from a few individuals, the Russian wetland scientists have really been the only wetland scientists to systematically attempt to incorporate scale into classification with the recognition of large scale “mire massifs” and internal differentiation of medium and small scale geomorphic forms (Galkina 1946, 1967; Ivanov 1981). The issue of scale in wetlands and its incorporation into classification of some specific mires in the region of Eurasia, was addressed in part by Kats (1971). Within the climatic zone of excess moisture, Kats (1971) distinguished four areas in which similar mires occurred. Similarity was based on structural peculiarities of

58 the mire formations and the average thickness of their peat deposits. In the climatic zone of deficient moisture, he recognised two additional areas in which the mires were similar and one more in the zone of unstable moisture. He argued that where mires exist in their natural state, that groups of mires which differed materially in the structure and composition of their plant cover could be distinguished. The macrotope of the mire massif of Bogdanovskaya-Gienev (1969) could also be viewed as a consanguineous suite. In this case the individual mires had coalesced, and the criteria were used for classifying the resulting complex. There were two criteria: 1. the phase and stage of development of the mesotopes at the time of unification, and 2. the course of their development after formation (Ivanov 1981). Four types of macrotope were recognised. Russia, Finland, Canada and US have also tried to amalgamate mire or peatland types into geographical regions or zones, such that a region contains wetlands with similar vegetation types, similar surface geometry, and similar trophic conditions (Gore 1983). These complex mire formations reflect the morphological and climatic peculiarities of huge geographic areas and repetitive smaller forms of relief across vast interfluvial expanses.

With the concept of consanguineous suites of wetlands (Semeniuk 1988) and wetland regions, this idea can be expanded to incorporate all types of wetlands and all climatic and biogeographic zones.

It is important to understand that the purpose of wetland classification is to emphasise natural and functional diversity for scientific investigations, resource management, and conservation. Not all management issues can be addressed through classification. Some remain simply management issues, e.g., vegetation succession, the impossibility of separating a wetland from its hydrological support system (Scott & Jones 1995).

The approach presented in this document has been designed to capture the spectrum of wetland diversity. To date we believe that a reduction in diversity of wetland types may have occurred where large areas of relatively homogeneous wetland vegetation cover several landform types masking small scale differences in processes, history, or hydroperiod. Various authors have tried to address this masking by vegetation to create a uniform large “habitat” by subdividing such areas on the basis of surface geomorphological patterns (Cajander 1913 cited in Botch & Masing 1983, Ivanov 1981, Zoltai & Pollett 1983). Reduced diversity has also occurred by overlooking the possibility of differentiating wetlands using the various distribution and arrangement patterns of vegetation brought about by different plant structures and composition, e.g., concentrically zoned wetlands, wetlands with patchy or complete homogeneous cover etc. (Golet & Larson 1976, Semeniuk et al. 1990). These patterns often give indications of gradients and processes, which themselves can be diverse. Overestimation of wetland diversity has occurred by equating wetland zones with wetlands, and has resulted, with the ensuing large number of categories, in difficulties in classification.

Wetland classifications, in general, also need to address the two dynamic influences on wetland form and development, i.e., climatic change and anthropogenic alteration. Changes in water levels and hydrological regime occur with climatic change as do changes in vegetation, however, in the former case, ancestral water levels can be related

59 to current water levels by saying that permanent inundation has changed to seasonal inundation. Stating that Potomogeton has changed to Typha does not allow any prediction to be made. In another wetland even in the same setting, Potomogeton may be replaced by a shrub or samphire species. In some instances, when the climatic change is short term, careful selection of criteria may bypass the need to re-classify a wetland. In the case study documented by LaBaugh et al. (1996) the climatically induced hydrochemical change, dominated by a specific cation or anion, significantly altered the biological response in the wetlands. When the primary level of classification does not include biological response, the classification of the wetland prior to such a chemical response, may still be appropriate.

The most important anthropogenic alterations which can occur are land clearing, drainage, and contamination. Each of these impacts can radically alter the internal stasis and interactions that occur between soils, plants and water (Semeniuk 2004), and therefore the type of wetland which results. A wetland classification should be such that these changes can be simply incorporated into the existing structure (see Section 7.0). This can transpire when the primary level of classification contains few and fundamental criteria.

This approach suggested in this document incorporates many of the tenets recommended for the classification of natural features, viz. that they are a component of either the land or the sea, that a scalar framework is established, that a systematic, hierarchical structure is employed, and that the resulting classification is practical.

60 6.0 A proposed classification for coastal wetlands (open coastal, embayed coastal, estuarine, and deltaic wetlands)

6.1 Preamble Coastal wetlands, occurring at the interface between land and sea, are located in an environment that can be topographically and sedimentologically the most complex on Earth. In the first instance, the coast commonly can be markedly erosional or depositional. If erosional, subject to wave, tidal and wind agencies, coasts can retreat at a great pace, developing a variety of coastal forms depending on rock types, physical and chemical coastal processes, biota, and climate. If depositional, coastal accretion also can proceed at a rapid pace, resulting from in situ accumulation of materials, from material transported along-shore, or from the land. Materials that develop coastal landforms can range from exogenic gravel, sand, and mud derived from the land by erosion of the coast, or from nearshore and offshore, to mostly in situ endogenic, biogenic, and abiotic gravel, sand, and mud, or biogenic rock (such as shoreline bioherms and biostromes). Interaction between land and sea, through waves, storms, wind, groundwater, hydrochemistry, evaporation, and rainfall, results in a plethora of landforms and other physical, chemical and biological products, often zoned physically, chemically, and biologically across the shore (Semeniuk 2004). In addition, rivers discharging into the sea, create local complex nodal points with the development of estuaries and deltas and their smaller scale physical, chemical and biological perturbations. As such, the shore is one of the most difficult of environments to classify with respect to wetlands.

However, while there is potential for complexity, it is also true there often is for a given location consistent processes operating along the land/sea interface (e.g., wave climate, wind systems), and a relatively widespread process can result in the development of a widespread unit. For example, erosion acting on a shore-exposed rock mass produces a linearly extensive cliffed coastline, or waves and wind acting on a sandy accreting shore produce an extensive beach and dune coast.

There have been a number of attempts in classifying coastal systems, though not with the emphasis that coasts are wetlands. Coastal geomorphologists and geologists have devised various genetic and descriptive classifications, ranging from megascale (e.g., the submergence/emergence concept of Johnson 1919; tectonic setting of colliding coast, passive, trailing coats, as stable and mobile areas suggested by Cotton 1952; eroded or accreted coast suggested by Valentin 1952 and Bloom 1965; and the wave climate approach suggested by Davies 1964), to mesoscale with the classification of types of deltas, estuaries and subdivision of estuaries into smaller components, to microscale (wherein geomorphic units such as tidal flats and beaches are noted, and facies and habitats have been identified; Semeniuk 1985, 1993; Kelletat 1995; Perillo 1995). As a result, there is a plethora of existing terms at various scales of reference.

Wetland scientists generally have lacked a systematic approach in classifying wet coastal systems. The currently accepted terminology for coastal wetlands incorporates vegetation and landscape terms, but they are not applied with consistency. Mangrove swamps and saltmarshes, for example, are viewed as types of wetlands, based on biotic attributes above

61 all else, whereas they are biotic responses on a tidal zone. Confusion is compounded when tidal flats are viewed as a type of wetland, but when there is colonization by vegetation of the same tidal flat in the appropriate climate and tidal level, they are classed with emphasis on their vegetation. Lack of a systematic scalar approach also can lead to a predicament in which smaller scalecoastal wetlands are treated with the same emphasis as larger scale units. An estuary, open to the sea comprising a deep water body fringed by tidal flats and saltmarshes or mangroves is viewed in totality by some authors as a type of wetland (an “estuary”), while the component parts (mangrove swamp, saltmarsh, and tidal flat) are equally viewed as wetlands without scalar discrimination. Lack of a systematic approach also has created a problem that not all landforms along the coast are recognised as coastal wetlands (e.g., deltas, rocky cliffs, beaches). Thus, there also is a plethora of existing coastal wetland terms, but these transcend scale, and there is inconsistent application of criteria.

Prior to formulating a classification for coastal wetlands, it is important to reaffirm what is meant by a coastal wetland (Fig. 6.1): the coastal fringe of the landmass that is wet by marine processes (tidal inundation, exposure to wave action, and any other marine wetting process); the fringe of the land that is coastal in origin and still wet (e.g., deltas); or coastal landscapes/waterscapes that bridge the transition between marine environment (with seawater) and land environment (with freshwater). The wetting process deriving from the marine environment includes tidal inundation, wave run-up, splash, and marine groundwater saturation. In this context, the coastal wet zone combines the tidal zone, the swash zone, the splash zone, and the groundwater wetted zone. Any surface to seaward of this defined coastal strip that is permanently inundated by marine water (e.g., permanently submerged marine areas even if as sounds, bays, invaginated areas, deep gulfs, waters to 6 m deep, and coral reefs) are excluded and firmly placed into the marine environment.

In this context, the term “coastal systems” and “coastal zones” should be not considered as equivalent to coastal wetlands (Figs. 6.2 & 6.3). To illustrate this using an archipelago setting: while an archipelago as a regional, megascale “coastal system” is distinctive, it is comprised of islands and surrounding deep to shallow water areas. The shores that comprise coastal wetland, i.e., the marine wetted land, while it may be complex (cf Semeniuk & Wurm 1988), is a thin interface that surrounds each island. It is also important to stress that many coastal classifications in the literature deal not with coastal wetlands, but with types of coastal systems, or coastal zones. Coastal systems and coastal zones involve the strand (to which we apply the term “coastal wetland”), the shallow subtidal (often to the depth of the prevailing waves base, or if in an archipelago setting, the surrounding deep water), the immediate supratidal zone, as well as the immediate inland zone that may have been developed by coastal progradation during the Holocene or even the Pleistocene (Fig. 6.4). There are, in fact, a range of defined coastal systems, and in recognising them, authors often amalgamate structure, or coastal form, with process, origin, with age. Examples include: archipelago coasts (SW Argentina, northern Scotland, and NW Australia), ria coasts (northern Scotland, and NW Australia), estuarine coasts (the Amazon estuary), deltaic coasts (the Nile delta, the Niger delta), gulfs, embayment coasts (The Wash), tidal flat coasts (Gulf of Carpentaria), chenier coasts (Louisianna), barrier coasts (The Coorong, Chesil Bank),

62 cuspate forelands (Dungeness, Point Becher), coral coasts (Ningaloo Reef), and cliff coasts (Great Australian Bight).

The diverse settings, determinative environments and expressions of coastal wetlands which contribute to the complexity observed in coastal zones include:

• climate setting (tropical, temperate, boreal and arctic; and arid versus humid) • oceanographic setting (macrotidal, mesotidal, microtidal, high wave energy, low wave energy) • position within the tidal zone (low, mid, high tidal surfaces) • morphology of the surface (flats, slopes, fans, creeks, spits/cheniers, beaches) • substrate texture type (gravel, sand mud, rocky shores, bouldery shores, rock pavements) • substrate composition (siliciclastic grains, carbonate grains, carbonate mud, gypsum) • biogenic influence (e.g., bioherms, biostromes, tidal forests, tidal seagrass)

The classification of coasts from a coastal wetland perspective needs to encompass this wide range of settings that can generate wet coastal environments listed above. However, this list is not provided to serve as criteria, but rather to ensure that the full gamut of coastal wetlands expressed in a wide range of environments are addressed.

6.2 Approach to classification of coastal`wetlands Because of the number and complexity of coastal wetland types, and the fact that certain geomorphic units such as tidal flats, deltas, and shoals can occur at different scales of observation (Fig. 6.5), the use of scale as a framework is strongly recommended. Classification of coastal landscape proposed here incorporates three scales:

large scale, or megascale (e.g., where rivers enter the sea, estuaries or deltas are developed, depending on extent of sedimentation to fill the valley tract); within this scale there are smaller scale units of mesoscale and microscale;

medium scale, or mesoscale, where coastal wetland units present themselves as relatively simple units such as beaches, tidal flats, and rocky shores;

small scale, or microscale, in which the wide diversity of form, substrates, biota, and salinity, developed in response to coastal gradients and coastal process, are evident.

Megascale involves scales of observation at > 10 km x 10 km to 1 km x 1 km; mesoscale involves scales of observation at < 1 km x 1 km to 100 m x 100 m; fine scale involves scales of observation at < 100 m x 100 km. These size classes are modifications of those presented in Semeniuk (1985), in that megascale, macroscale, mesoscale, and microscale of Semeniuk (1985) have been simplified to three scales.

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The core coastal wetland designations are at the medium scale, i.e., mesoscale. The megascale provides a broad descriptor of the setting of the coastal wetlands, and as noted above, coastal systems at this scale are not coastal wetlands. The microscale provides subdivision of the core coastal wetland units into microscale coastal wetlands, and provides features for use as fine-scale descriptors. Microscale wetlands, in essence, are broadly equivalent to habitat. The medium scale (or mesoscale), and the small scale (or microscale) classes and their descriptors should allow researchers, wetland scientists, and coastal managers to classify site-specific coastal wetlands on-site and to some extent from aerial photographs. The philosophy of approach in classifying coastal wetlands proposed here is summarised in Fig. 6.5.

6.3 Megascale coastal setting Coastal systems identified at the megascale provide descriptors for the setting of coastal wetlands. As noted above, these should not be viewed as being coastal wetlands themselves. In addition to cuastal systems, other features at the megascale for use as descriptors are: oceanographic setting (e.g., wave dominated; tide-dominated;, or microtidal < 2 m, mesotidal 2-4 m, macrotidal 4-8 m, extreme macrotidal > 8 m), and climate (e.g., tropical arid, tropical humid, temperate humid, boreal humid).

Four types of megascale coastal systems are recognised, as related to the interaction between the marine environment and riverine input. Applied as adjective descriptors, these are (Fig. 6.6):

1. open coastal 2. embayed coastal 3. estuarine 4. deltaic

These can be grouped into those wholly marine or those mixed marine an riverine.

wholly marine mixed marine and riverine open coastal estuarine embayed coastal delatic

The open coastal setting is a wholly marine environment interfacing with the landmass, without riverine input. It can be rocky (as cliffs), bouldery, gravelly, sandy, or muddy, and can be high wave or low wave energy, or macrotiidal, mesotidal or microtidal, and can be straight to curved, vertical to sloping to nearly flat. The embayed coastal setting is one where a marine environment interfaces with an embayed to invaginated landmass usually founded on a riverine system, though not necessarily with riverine input (e.g., ria). It too can vary in substrate, wave energy, and tidal regime, but it has the added complication that often its headwaters have inherited features of the fluvial environment (e.g., alluvial fans debouching into the marine environment). Where large embayed coasts have no underlying

64 riverine origin, their peninsular nature may be related to tectonism, or to marine inundation of ancestral ridge-and-valley topography.

Estuaries are developed where rivers enter the sea, nut with insufficient sediments to fill the valley tract to create a seaward-projecting body of sediment (a delta). The estuarine sediments tend to be located dominantly at the head, or are shore-hugging. Estuaries are characterised by a water quality transitional between marine and freshwater, with biota adapted to brackish transitional water (true estuarine biota), or able to tolerate alternating marine, brackish and freshwater inundation (euryhaline and stenohaline components). In this context, the concept of an estuary largely is based on a salinity transition, and not on a physiographic setting. With perennial river flow, as in many northern European estuaries, there is a permanent to semi-permanent marine to freshwater transition, but where flow is seasonal, as in arid, semi-arid, or subhumid regions (e.g., Australia, South Africa), this transition exists only seasonally, and estuarine conditions are reflected only in the biota that tolerate extreme fluctuating salinity. To identify estuarine embayments that receive perennial freshwater from those that receive freshwater only seasonally, “permanent” and “seasonal” may be added to the term estuary. During the time that freshwater ceases to flow in a seasonal estuary, the gulf, coastally invaginated area, or funnel where the freshwater to marine transition resides reverst to marine conditions and becomes essentially an embayed coast.

There also are some as yet unresolved issues with estuaries: for instance, that they grade from being intermittently to seasonally barred to a permanently barred near-coastal freshwater lagoon, and there is no consensus as to what extent freshwater must be delivered to an embayment for it to be considered an estuarine. Furthr to this latter issue, some authors even consider that estuaries are developed where freshwater is delivered to the marine coastal environment by subterranean seepage, and others working on stygofauna consider the underground brackish transition groundwater zone at the junction between marine and freshwater under the coastal zone (i.e., the Ghyben-Herzberg interface) to be “estuarine”. These issues are not discussed in detail here, as they are beyond the scope of this paper, but we reaffirm that we consider estuary to be an environment where there is major fresh water to seawater transition via riverine delivery.

Deltas are developed where rivers enter the sea, accumulating sediments within the valley tract sufficiently to create a seaward-projecting body of sediment. While strictly estuarine in view of their salinity transition, they are not regarded as such by coastal scientist as the sedimentary accumulation implicitly has precedence in the terminology, i.e., they are deltas in preference to being estuaries..

The megascale descriptors carry implication of the complexity of coastal wetlands that may occur within. Open coastal systems tend to be subject to a more consistent and widespread oceanographic processes such as wave energy or tides, and environemnts therein tend to be more simple and widespread than those in embayments, where with diffraction and reflection of wave energy and with smaller sheltered settings there is development of more complex sub-environments. The estuarine and deltaic systems, with a variety of

65 complicated internal forms, and with freshwater interactions, present some of the most compex array of smaller scale geomorphic and habitat features along the coast.

The examples of coastal forms encompassed by megascale coastal types are listed in the Table below.

Megascale coast Examples open coastal extensive rocky shore, beach/dune shore, tidal flat coast, barrier coast embayed coastal sound, gulf, ria, fjord estuarine funnel estuary, estuarine lagoon, ria estuary deltaic fluvial dominated delta, wave dominated delta, tide dominated delta

In terms of coastal interrelationship, there is a gradation in coastal form and to some extent origin from open coastal systems, to embayed coastal systems to estuaries, and deltas (Fig. 6.6). In this context, the deltaic systems are the most complex of coastal types, bringing in both parent (inherited) coastal features and constructed deltaic features (regardless of whether they have been constructed dominantly by fluvial, wave, or tidal processes), and they provide the most complicated set of environments for which to draw the land-sea boundary.

6.4 The mesoscale coastal wetlands Within the megascale coastal units, a diverse range of mesoscale coastal wetlands may be developed (Fig. 6.7). The mesoscale units include the following:

beach rock pavement tidal flat rocky shore strandplain bouldery shore spit alluvial fan chenier tidal creek shoal tidal lagoon tombolo biostrome tidal delta bioherm

These mesoscale units are the basic coastal wetland units.

While some established terms are used to denote coastal wetlands, it is important to note that the meaning of these terms and their implied extent traditionally in other contexts and coastal disciplines extends beyond that used fo coastal wetlands. This applies to beaches, spits, rocky pavements, rocky shores, bouldery shores, biostromes and bioherms. For instance, traditionally a beach comprises the shallow subtidal, the swash, the storm zone and foredune zone, and often is divided into nearshore, forshore, swash, berm and foredune, but the term “beach” as a coastal wetland involves only the swash and splash zone (Fig. 6.8). For a second example: traditionally, rocky shores comprise the shallow subtidal, the swash zone, and any vertical cliff above the wetted zone. The term “rocky shore” as a coastal wetland involves only the shore-wetted zone (Fig. 6.8).

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A description of the mesoscale coastal wetland units and their setting is presented below:

Mesoscale Unit Description and setting beach moderately steep to low inclined sandy tidal surface, usually wave- dominated; faces open ocean; locally indurated to form beach rock tidal flat low to very low inclined to flat tidal surface, usually muddy, but can be sandy, gravelly, or shelly; high tidal parts usually muddy, mid tidal parts usually mixed sand and mud, and low tidal parts usually sandy; faces open ocean or is part of an estuary or delta strandplain low gradient surface comprised of sand ridges and cheniers alternating with high tidal swales and flats; usually part of a delta spit low relief linear to curved sandy tidal to supratidal bar; part of an open coast, estuary, or delta chenier isolated low relief linear to curved sandy tidal to supratidal bar; part of an open coast, estuary, or delta shoal low relief mounded, linear to curved sandy tidal bar; part of an open coast, embayed coast, estuary, or delta tombolo low relief mounded, linear, shorpendicular connective sandy bar; part of an open coast or embayed coast tidal delta often fan-shaped assemblage of shoals at mouth of an inlet channel rock pavement near-horizontal to horizontal tidal pavement of rock; part of an open coast, estuary, or delta rocky shore steep to vertical (cliff) rock; part of an open coast, or estuary bouldery shore steep bouldery surface; part of an open coast, or estuary alluvial fan moderately to low inclined discrete, fan-shaped gravelly to sandy tidal surface; lower parts may be wave-dominated; usually part of an invaginated coast, or an estuary tidal creek ramifying to meandering creek system; comprised of channel, banks, and mid-channel shoals; part of an open coast, estuary, or delta tidal lagoon usually linear depression behind a sand barrier; part of an open coast, estuary, or delta biostrome flat surfaces underlain by biogenically constructed aggregations of hard-shelled organisms, viz., mussel beds, oyster beds, barnacle beds, serpulid worm beds, sabellid worm beds, coral beds, coralline algal beds bioherm discrete, mounded structures underlain by biogenically constructed aggregations of hard-shelled organisms, viz., mussel beds, oyster beds, barnacle beds, serpulid worm beds, sabellid worm beds, coral beds, coralline algal beds

Examples of mesoscale units within each megascale coastal type are noted in the Table below.

Megascale coasts Mesoscale coastal wetlands (bracketed units are uncommon)

67 open coastal beach; tidal flat; shoal; rock pavement; rocky shore; bouldery shore; spit; tombolo; (tidal delta, chenier, tidal creek, tidal lagoon, biostrome, bioherm) embayed coastal beach; tidal flat; spit; chenier; shoal; tombolo; tidal delta; rock pavement; rocky shore; bouldery shore; alluvial fan; tidal creek; tidal lagoon,; biostrome surface; bioherm estuarine beach; tidal flat; spit; chenier; shoal; tombolo; tidal delta; rock pavement; rocky shore; bouldery shore; alluvial fan; tidal creek; tidal lagoon; biostrome; bioherm deltaic beach; tidal flat; strandplain; spit; chenier; shoal; tidal delta; rock pavement; alluvial fan; tidal creek; tidal lagoon

6.5 The microscale coastal wetlands: subdivision of mesoscale At the finest scale, the microscale units within the mesoscale coastal wetlands along the coast are identified on tidal level or smaller scale morphological subdivision; they are:

beach low tidal rock pavement beach berm high tidal rocky shore beach rock mid tidal rocky shore high tidal flat low tidal rocky shore mid tidal flat cliff low tidal flat low tidal bench strandplain lagoon high tidal bench strandplain ridge high tidal bouldery shore strandplain shoal mid tidal bouldery shore strandplain flat low tidal bouldery shore tidal lagoon high tidal alluvial fan spit mid tidal alluvial fan chenier low tidal alluvial fan shoal tidal creek bank tombolo tidal creek floor tidal delta tidal creek shoal high tidal rock pavement biostrome mid tidal rock pavement bioherm

These microscale coastal wetlands are the habitats developed along he coast. Note that some of the mesoscale units reappear at the microscale (viz., beach, spit, chenier, shoal, tidal lagoon, biostrome, and bioherm. A description of microscale units is presented in the Table below:

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Micoscale Unit Description and setting beach moderately steep to low inclined sandy tidal surface, usually wave-dominated beach berm generally flat to low inclined backshore sandy surface beachrock indurated mid tidal to upper tidal part of beach, comprised of ribbons, sheets, and slabs of indurated beach sand high tidal flat low to very low inclined to flat tidal surface, usually muddy, located between high water neap tide and the highest tidal level; usually with hypersaline ground water; in tropical regions, extreme hypersalinity develops salt flats; in temperate regions this surface is inhabited by samphires and saltmarsh mid tidal flat low inclined to flat tidal surface, usually muddy, or mixed sand and mud, located between high water neap tide and low water neap tide; in tropical regions the mid tide to mean high water spring tidal level is inhabited by mangroves; low tidal flat low to very low inclined to flat tidal surface, usually sandy, gravelly, or shelly, located between low water neap tide and the lowest tidal level; strandplain lagoon low gradient surface inundated at high tide, exposed at low tide, located between sand ridges and cheniers; usually muddy or muddy sand; often inhabited by mangroves, saltmarsh, or samphires, or may be vegetation- free strandplain ridge moderate relief linear sandy ridge, crest tidally inundated on the high tide, or crest low supratidal strandplain shoal moderate relief sandy mound, ridge, crest tidally inundated on the high tide and exposed on low tide, located within lagoon strandplain flat low gradient sand or mud surface located between sand ridges and cheniers, and flooded on the highest tides tidal lagoon as at mesoscale, a linear depression behind a sand barrier - no subdivision spit as at meso scale, a low relief linear to curved sandy tidal to supratidal bar - no subdivision chenier as at mesoscale, an isolated low relief linear to curved sandy tidal to supratidal bar - no subdivision shoal as at mesoscale, a low relief mounded, linear to curved sandy tidal bar - no subdivision tombolo as at mesoscale, a low relief mounded, shore-prallel sandy body connecting the main shore to an nearshore island; tidal parts are coastal wetland; no subdivision tidal delta as at mesoscale, a fan-shaped assemblage of shoals at the mouth of an inlet channel; may be ebb tidal or flood tidal deltas; tidal parts are coastal wetlands; no subdivision high tidal rock near-horizontal to horizontal tidal pavement of rock located above high water neap tidal level; underlain by a

69 pavement variety of rock, the most common of which is limestone mid tidal rock low inclined to near-horizontal tidal pavement of rock located between high and low water neap tidal level; pavement underlain by a variety of rock, the most common of which is limestone high tidal rock near-horizontal to horizontal tidal pavement of rock located below low water neap tidal level; underlain by a pavement variety of rock, the most common of which is limestone high tidal rocky shore smooth, regular to irregular, steeply inclined to vertical (cliff) rock surface located above high water neap tide; underlain by a variety of rock mid tidal rocky shore smooth, regular to irregular, steeply inclined to vertical (cliff) rock surface located between high and low water neap tide; underlain by a variety of rock low tidal rocky shore smooth, regular to irregular, steeply inclined to vertical (cliff) rock surface located below low water neap tide; underlain by a variety of rock high tidal bench as part of a rocky shore, a narrow to wide near horizontal surface cut into shore at a specific level at high tide (e.g., at high water spring tidal level); underlain by a variety of rock, but the most common is limestone low tidal bench as part of a rocky shore, a narrow to wide near horizontal surface cut into shore at a specific level at low tide (e.g., at low water spring tidal level); underlain by a variety of rock, but the most common is limestone cliff as part of a rocky shore, locally developed vertical wall cut at any tidal level high tidal bouldery steep, bouldery surface located above high water neap tide; underlain by a variety of boulder types shore mid tidal bouldery steep, bouldery surface located between high and low water neap tide; underlain by a variety of boulder types shore low tidal bouldery steep, bouldery surface located below low water neap tide; underlain by a variety of boulder types shore high tidal alluvial fan moderately to low inclined discrete, fan-shaped gravelly to sandy surface above high water neap tidal level mid tidal alluvial fan moderately to low inclined discrete, fan-shaped gravelly to sandy surface between high and low water neap tidal level low tidal alluvial fan moderately to low inclined discrete, fan-shaped gravelly to sandy surface located below low water neap tidal level tidal creek bank steep bank of tidal creek, located between high and low tide, underlain usually by mud; may be vegetated by mangroves, saltmarsh, or samphire

70 tidal creek floor near-horizontal floor of tidal creek channel, exposed on low tide; underlain by sand, or mud tidal creek shoal mounded, usually linear sand body on the floor of tidal creeks biostrome as at mesoscale, a flat surface biogenically constructed of hard-shelled organisms - no subdivision bioherm as at mesoscale, a discrete, mounded structure constructed of hard-shelled organisms - no subdivision

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The types of microscale coastal wetlands within each of mesoscale coastal wetlands are noted as follows:

Mesoscale unit Microscale units beach beach; beach berm; beach rock tidal flat high tidal flat; mid tidal flat; low tidal flat strandplain strandplain lagoon; strandplain ridge; strandplain shoal; strandplain flat spit not subdivided chenier not subdivided shoal not subdivided tombolo not subdivided rock pavement high tidal rock pavement; mid tidal rock pavement; low tidal rock pavement rocky shore high tidal rocky shore; mid tidal rocky shore; low tidal rocky shore; low tidal bench; high tidal bench; cliff bouldery shore high tidal bouldery shore; mid tidal bouldery shore; low tidal bouldery shore alluvial fan high tidal alluvial fan; mid tidal alluvial fan; low tidal alluvial fan tidal creek tidal creek bank; tidal creek floor; tidal creek shoal tidal lagoon not subdivided biostrome not subdivided bioherm not subdivided

6.5 Descriptors of finer scale coastal units The various coastal wetlands require descriptors to adequately categorise them, and to this objective a list of substrate, hydrochemical, and biotic descriptors is provided. Type of landform is already incorporated into the terms tidal flat, beach, rocky shore, etc., and hydrological attributes are incorporated in the terms “tidal”, and “high, mid, and low tidal”.

Attribute Descriptor tidal range low tidal; mid tidal; high tidal wave energy wave-dominated substrate texture muddy; sandy; gravelly; shelly substrate composition terrigenous; carbonate substrate micro- sediment surface: smooth; rippled; mega-rippled; hummocky; burrow- topography pocked; rocks: smooth, micro-pinnacled, pitted hydrochemical marine; metahaline; hypersaline biota mangrove-vegetated; saltmarsh vegetated; samphire vegetated; seagrass vegetated; algal mat covered; stromatolitic; kelp vegetated; algal turf vegetated; biofilm covered; oyster encrusted; barnacle encrusted; serpulid worm encrusted; sabellid worm encrusted; coral encrusted; calcareous algal encrusted; mollusc inhabited

72 6.7 Application of the classification system The classification of coastal wetlands can be applied at several levels of detail. At the largest scale, for use as a descriptor, the coast may be classed as (1) open coastal, (2) embayed coastal, (3) estuarine, or (4) deltaic. Descriptors of tidal range, substrate type, or delta type also may be added if required., viz., macrotidal embayed coastal, or rocky embayed coastal, or fluvial-dominated deltaic. When fully applied, the classification is employed in scalar sequence, as illustrated in the first examples below. If required, or desired, the system can be applied at the fine scale only, with or without descriptors, and can be applied to a site-specific wetland in the field without contextual descriptots. Fully applied, though, the classification provides for a systematic discrimination between coastal wetlands down to the smallest scale.

6.7.1 Fully applied classification To be fully applied, the researcher, coastal wetland scientist, or coastal manager needs to have a set of aerial photographs or maps that cover the large scale coast. Thereafter, a site visit is required to document substrates, microtopographic features, groundwater salinity, and other attributes not visible on aerial photographs. Familiarity with the area and the phototones of coastal zones, their substrates (sand versus mud) and vegetation patterns (samphire versus mangroves, or the various species of mangroves) will allow for categorisation of some features without site visits.

Firstly, the coast is assigned to one of the four megascale coastal types, and to a tidal and climatic setting. With a site visit, a coastal wetland is assigned to one of the mesoscale units, e.g., a tidal flat, and information is collected as to tidal level, salinity of groundwater, substrate characteristics, and biota. In this example, from Roebuck Bay, NW Australia, three sites on a tidal flat are described.

The information obtained for site 1, the high tidal zone may be as follows: Large scale coastal setting embayed coastal Climate setting Tropical semi- arid Tidal range macrotidal Mesoscale coastal type tidal flat Tidal level of unit high tidal Substrate texture mud Substrate composition carbonate mud Substrate microtopography smooth Hydrochemical: salinity of groundwater hypersaline Biota samphire vegetated

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The information obtained for site 2, the mid tidal zone may be as follows: Large scale coastal setting embayed coastal Climate setting Tropical semi-arid Tidal range macrotidal Mesoscale coastal type tidal flat Tidal level of unit mid tidal Substrate texture mud Substrate composition carbonate mud Substrate microtopography smooth Hydrochemical: salinity of groundwater hypersaline Biota mangrove vegetated

The information obtained for site 3, the low tidal zone may be as follows: Large scale coastal setting embayed coastal Climate setting Tropical semi-arid Tidal range macrotidal Mesoscale coastal type tidal flat Tidal level of unit low tidal Substrate texture sand Substrate composition quartz sand Substrate microtopography hummocky Hydrochemical: salinity of groundwater marine Biota crustacea-inhabited

Then the information is aggregated with full use of descriptors to provide a comprehensive classification of these coastal wetlands as follows:

Site 1: Tropical semi-arid, embayed coastal, macrotidal, samphire-vegetated, hypersaline, carbonate mud, smooth, high tidal flat Site 2: Tropical arid, embayed coastal, macrotidal, mangrove-vegetated, hypersaline, carbonate mud, smooth, mid tidal flat Site 3: Tropical arid, embayed coastal, macrotidal, crustacea-inhabited, marine, quartz sand, hummocky, low tidal flat

The information also can be pruned down to be more succinct if necessary (since some descriptors such as “high tidal” commonly confer the notion of hypersalinity), or tailored to suit specific coastal wetland needs (e.g., emphasis on biota):

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Site 1: Tropical semi-arid, embayed coastal, macrotidal, high tidal fla Site 2: Tropical semi-arid, embayed coastal, macrotidal, mid tidal flat Site 3: Tropical semi-arid, embayed coastal, macrotidal, low tidal flat

Site 1: Tropical semi-arid, embayed coastal, samphire-vegetated, hypersaline, high tidal flat Site 2: Tropical semi-arid, embayed coastal, mangrove-vegetated, hypersaline, mid tidal flat Site 3: Tropical semi-arid, embayed coastal,, crustacea-inhabited, marine, low tidal flat

In another example, two sites from Eighty Mile Beach, in arid NW Australia, a sloping beach shore with an adjoining flat exposed at low tide, are described.

The information obtained for site 1, the mid to high tidal zone may be as follows: Large scale coastal setting open coastal Climate setting Tropical arid Tidal range macrotidal Mesoscale coastal type beach Tidal level of unit mid to high tidal Substrate texture sand Substrate composition quartz sand Substrate microtopography smooth Hydrochemical: salinity of groundwater marine Biota Donax inhabited

The information obtained for site 2, the low tidal zone may be as follows: Large scale coastal setting open coastal Climate setting Tropical arid Tidal range macrotidal Mesoscale coastal type tidal flat Tidal level of unit low tidal Substrate texture sand Substrate composition quartz sand Substrate microtopography smooth Hydrochemical: salinity of groundwater marine Biota mollusc inhabited

Then the information is aggregated with full use of descriptors to provide a comprehensive classification of these coastal wetlands as follows::

75 Site 1: Tropical arid, open coastal, macrotidal, marine, quartz sand, smooth, mid to high tidal beach Site 2: Tropical arid, open coastal, macrotidal, marine, quartz sand, smooth, low tidal flat

Again, the information can be pruned down to be more succinct if necessary, or tailored to suit specific coastal wetland needs (e.g., emphasis on biota):

Site 1: Tropical arid, open coastal, macrotidal, mid to high tidal beach Site 2: Tropical arid, open coastal, macrotidal, smooth, low tidal flat

Site 1: Tropical arid, open coastal, Donax-inhabited, marine, mid to high tidal beac Site 2: Tropical arid, open coastal, mixed mollusc dominated, marine, low tidal flat

The level of detail required of course depends on the purpose for the information. Fully classified, the information may be of value to researchers of avifaunal coastal usage, or ecological frameworks. Information pruned to simpler terminology may be of use in coastal inventory maps, or in coastal management.

6.7.2 Partly applied classification at mesoscale level Classification may proceed only mesoscale, if that is all that is required. This level of classification need only be desk-top, if the researcher, wetland scientist, or coastal manager has skills in interpreting stereoscopic aerial photographs or detailed 1:100,000 topographic maps. A site visit of course can validate the desk-top information.

In the examples presented below, again, the coast is assigned to one of the four megascale coastal types. Thereafter, the coast is assigned to one of the mesoscale classes. To provide descriptors, tidal range information can be obtained from the literature, and aerial photographs will provide information on the absence/presence of mangroves, saltmarsh, and samphires. In each example, a different type of coast is described.

The information obtained for site 1, from Albany, southern Western Australia, a rocky shore, may be as follows: Large scale coastal setting embayed Climate setting Temperate humid Mesoscale coastal type rocky shore Tidal range microtidal

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The information obtained for site 2, from the Gascoyne delta, in mid coastal Western Australia, a mangrove-vegetated tidal flat may be as follows: Large scale coastal setting deltaic Climate setting Subtropical arid Mesoscale coastal type tidal flat Tidal range microtidal Biota mangrove vegetated

The information obtained for site 3, from Nornalup Inlet, southern Western Australia, a beach within an estuary, may be as follows: Large scale coastal setting estuarine Climate setting Temperate humid Mesoscale coastal type beach Tidal range microtidal

Then the information is aggregated to provide a classification of these coastal wetlands at the mesoscale as follows:

Site 1: Temperate humid, embayed coastal, microtidal, rocky shore Site 2: Subtropical aris, deltaic, microtidal, mangrove-vegetated, tidal flat Site 3: Temperate humid, estuarine, microtidal, beach

6.7.3 Partly applied classification at microscale level The classification can be applied at the detailed, fine scale level only, without larger scale context. For instance, on-site in the field, with accumulation of appropriate information, the microscale features of a coastal wetland could be classified according to these six Western Australian examples drawn from Port Warrender, Roebuck Bay, Port Hedland, Point Samson, Dampier Archipelago, Shark Bay (megascale setting has not been included for these examples):

Site 1: mussel-inhabited, macrotidal, marine, terrigenous mud, burrow-pocked, low tidal flat Site 2: samphire-vegetated, macrotidal, hypersaline, carbonate mud, smooth, high tidal flat Site 3: coral-crusted, macrotidal, marine, low tidal limestone bench Site 4: oyster-inhabited, macrotidal, marine, micropinnacled, limestone, mid tidal rocky shore Site 5: crustacea-inhabited, macrotidal, marine, carbonate sandy, hummocky, low tidal flat Site 6: stromatolitic, microtidal, hypersaline, carbonate mud, smooth, high tidal flat

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6.8 Case examples to illustrate the use of the classification The variety of coastal types and their smaller scale features are described here with four examples drawn from Western Australia to illustrate how at each of the scales of observation, the classification deals with the coastal type. The examples are drawn from:

1. King Sound (in semi-arid, tropical north Western Australia): here the classification must deal with an extreme macrotidal moderately complex coast; 2. Hopeless Reach - Hamelin Pool (Shark Bay, in arid, subtropical/tropical mid Western Australia): here the classification must deal with a microtidal highly complex coastal system; 3. Gascoyne Delta (in arid, subtropical/tropical mid Western Australia): here the classification must deal with a microtidal complex coast; 4. the Leschenault - Preston coastal sector of the Swan Coastal Plain (in subhumid, subtropical southwestern Western Australia): here the classification must deal with a microtidal simple coast.

6.8.1 King Sound King Sound situated in semi-arid, tropical north Western Australia, is a large funnel- shaped gulf, that annually is flooded with freshwater from the Fitzroy River over the period of the monsoon in summer. At the largest scale, King Sound is an embayed coast, with a tide-dominated delta at its head which is seasonally estuarine. The coast has an extreme macrotidal regime, and is moderately complex in its array of coastal landforms (Semeniuk 1982). Along the shore, there are a range of coastal landforms that at the mesoscale include tidal flats, beaches, spits, cheniers, shoals, tidal creeks, rocky shores, and mid tidal cliffs. In detail, King Sound presents numerous fine scale coastal forms that include high tidal mud flats, mid tidal mud flats, mid tidal mud/sand flats, low tidal mud flats, low tidal sand flats, low tidal gravel flats, beaches, spits, cheniers, shoals, tidal creeks, rocky shores, and mid tidal cliffs.

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The coastal wetlands in this area, outside of the zone of the seasonal estuarine conditions, incorporating the appropriate descriptors, are classified as follows:

1. Tropical semi-arid, embayed coastal, macrotidal, hypersaline, terrigenous mud, high tidal mud flat 2. Tropical semi-arid, embayed coastal, macrotidal, mangrove-vegetated, marine to hypersaline, terrigenous mud, mid tidal mud flat 3. Tropical semi-arid, embayed coastal, macrotidal, burrow-pocked, marine, terrigenous mud, mid tidal mud/sand flat 4. Tropical semi-arid, embayed coastal, macrotidal, burrow-pocked, marine, terrigenous mud, low tidal mud flat 5. Tropical semi-arid, embayed coastal, macrotidal, megarippled, marine, quartz sand, low tidal sand flat 6. Tropical semi-arid, embayed coastal, macrotidal, smooth, marine, limestone pebble, low tidal gravel flat 7. Tropical semi-arid, embayed coastal, macrotidal, smooth, marine, quartz sand, beach 8. Tropical semi-arid, embayed coastal, macrotidal, marine, quartz sand, spit 9. Tropical semi-arid, embayed coastal, macrotidal, marine, quartz sand, chenier 10. Tropical semi-arid, embayed coastal, macrotidal, megarippled, marine, quartz sand, shoal 11. Tropical semi-arid, embayed coastal, macrotidal, marine, mud-walled tidal creek 12. Tropical semi-arid, embayed coastal, macrotidal, marine, rocky shore 13. Tropical semi-arid, embayed coastal, macrotidal, marine, mud-walled mid tidal cliff

If these units were inside the zone of the seasonally estuarine conditions, they would be classified as above, but with “embayed coastal” replaced by “seasonally estuarine”.

6.8.2 Hopeless Reach - Hamelin Pool Hopeless Reach - Hamelin Pool, part of the Shark Bay complex, is situated in arid, subtropical/tropical mid Western Australia (Logan et al 1974). The combined area of Hopeless Reach - Hamelin Pool forms the southern large embayment of a twin embayment complex. At the largest scale, Hopeless Reach - Hamelin Pool is an embayed coast. There is a regional salinity gradient of embayment waters from oceanic in the north (35,000 ppm) to hypersaline in the south (55,000 ppm). The shore is wave dominated, and microtidal. It is a very complex system in terms of its array of coastal landforms (Logan et al 1974). Along the shore, there are a range of coastal landforms that at the mesoscale include tidal flats, beaches, spits, shoals, rocky shores, and a wave-dominated delta debouching in metahaline environment. In detail, Hopeless Reach - Hamelin Pool presents a myriad of fine scale coastal forms that include supratidal mudflats, (stromatolitic) high tidal mud flats and mid tidal mud flats, stromatolitic bioherms, mangrove-vegetated mid-high tidal mud flat, breccia pavements, rock pavement, ooid sand beaches, quartz sand beaches, shell gravel beaches, low tidal sand flats, spits, cheniers, shoals, rocky shores and cliffs.

79 The coastal wetlands in this area, within the zone bathed in oceanic to metahaline waters, are classified as follows:

1. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, quartz sand beach 2. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, quartz sand, low tidal sand flat 3. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, carbonate and quartz sand spit 4. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, carbonate and quartz sand chenier 5. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, carbonate and quartz sand shoal 6. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, mangrove- vegetated mid-high tidal mud flat 7. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, limestone rocky shore 8. Subtropical/tropical arid, embayed coastal, microtidal, marine/metahaline, limestone cliff

The coastal wetlands in this area, within the zone bathed in hypersaline waters, are classified as follows:

1. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, carbonate mud, supratidal mudflat 2. Subtropical/tropical arid, embayed coastal, microtidal, stromatolitic, hypersaline, carbonate mud, high tidal mud flats and mid tidal mud flat 3. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, stromatolitic bioherm 4. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, carbonate clast, breccia pavement 5. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, carbonate crust, rock pavement 6. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, carbonate ooid sand beach 7. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, quartz sand beach 8. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, shell gravel beach rock 9. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, shell gravel beach 10. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, shell gravel spit 11. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, quartz and carbonate sand spit 12. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, quartz and carbonate sand chenier 13. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, quartz and carbonate sand shoal 14. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, ooid sand shoal 15. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, quartz and carbonate

80 sand low tidal flat 16. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, shell gravel low tidal flat 17. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, limestone rocky shore 18. Subtropical/tropical arid, embayed coastal, microtidal, hypersaline, limestone cliff

6.8.3 Gascoyne Delta The Gascoyne Delta is situated in arid, subtropical/tropical mid Western Australia Johnson 1982). At the largest scale, the Gascoyne Delta is a wave-dominated microtidal delta set in a marine environment. It is a moderately complex system in terms of its array of coastal landforms (Johnson 1982). Along the shore, there are a range of coastal landforms that at the mesoscale include strandplains, tidal flats, beaches, spits, and shoals. In detail, the delta presents numerous fine scale coastal forms that include supratidal mudflats, mangrove-vegetated mid to high tidal mud flats, low tidal sand flats, quartz sand beaches, spits, cheniers, shoals, and tidal creeks.

The coastal wetlands in this area are classified as follows:

1. Subtropical/tropical arid, deltaic, microtidal, marine, terrigenous supratidal flat 2. Subtropical/tropical arid, deltaic, microtidal, marine, mangrove-vegetated mid-high tidal mud flat 3. Subtropical/tropical arid, deltaic, microtidal, marine, hummocky to burrow-pocked, quartz sand, low tidal sand flat 4. Subtropical/tropical arid, deltaic, microtidal, marine, smooth, quartz sand beach 5. Subtropical/tropical arid, deltaic, microtidal, marine, carbonate and quartz sand spit 6. Subtropical/tropical arid, deltaic, microtidal, marine, carbonate and quartz sand chenier 7. Subtropical/tropical arid, deltaic, microtidal, marine, carbonate and quartz, smooth to hummocky, sand shoal 8. Subtropical/tropical arid, deltaic, microtidal, marine, mangrove-vegetated tidal creek

6.8.4 Leschenault-Preston coastal sector The Leschenault-Preston coastal sector of the Swan Coastal Plain is located in subhumid, subtropical southwestern Western Australia (Searle & Semeniuk 1985), and represents an open coastal, wave-dominated, microtidal simple coast. At the largest scale, the Leschenault-Preston coastal sector is a sandy barrier dune system. It is a simple coast in terms of its array of coastal landforms: coastal landforms at the mesoscale include beach and local limestone rocky reefs; at the fine scale coastal forms include sandy beaches, gravel beaches, and limestone rocky reefs.

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The coastal wetlands in this area are classified as follows:

1. Subtropical, subhumid, open coastal, microtidal, marine, quartz sand beach 2. Subtropical, subhumid, open coastal, microtidal, marine, shell gravel beach 3. Subtropical, subhumid, open coastal, microtidal, marine, limestone rocky reef

6.9 Discussion, and summary The classification of coastal wetlands presented here is based on approaching coastal systems at three scales. At the largest scale, involving large tracts of coast, the subdivision is simple, resolving to four categories, and this level of classification is used as a desrcriptor. At the middle scale, it also is simple, identifying basic coastal landform units, without detailed subdivision or description, though using the megascale coastal setting, climate setting, and tidal setting as rudimentary descriptors. At the smallest scale, the classification is detailed. It is based on identifying geomorphic units (the coastal land) developed at the shore, and augmenting the class of landform with various descriptors. As such, the coastal wetland classification continues the theme that wetland classification in the first instance should be based firmly on land and water characteristics.

Thus, in this proposal, we proffer the geomorphic approach to the classification of the smallest and middle scale units as the core of the classification, and add descriptors to capture the variety of coastal wetlands. The biological, hydrochemical, and physical features of the coast are added as appropriate descriptors.

This classification is the most detailed and systematic produced for coastal wetlands to date, and it is the first time that an integrated scalar approach has been provided for classifying these type of wetlands. The detail of the classification can be included as required for appropriate purposes. Regional inventories, for instance, need not proceed further than the middle scale (with the nomenclature implying that further descriptors of tidal level, water salinity, substrate type, and biota can be added). More detailed requirement for ecological studies may need to proceed to the fine scale nomenclature.

The four case studies, representing a variety of coastal setting, show that the coastal wetland classification can be applied successfully to a wide range of coasts. Note should also be made that the classification of the coastal examples, presented in Section 6.7, is based on real coasts and not theoretical constructs.

82 7.0 A proposed classification for anthropogenically created or altered wetlands

7.1 Preamble Mankind has modified and alienated natural wetland habitat and its global pattern of distribution through excavation, infilling, drainage, vegetation clearing, and active management, and similarly has altered landscape and hydrology by creating artificial water bodies and wet environments, in both inland and coastal areas. While clearly in many instances no longer natural, and in many cases wholly artificial, these wet land- based and coastal environments function as important avifaunal habitats, sanctuaries for flora and fauna, fisheries, and areas of food and other natural resource production and harvesting.

In the context of the current environmental state of the world’s wetlands, the goal for wetland classification should be the inclusion of all types of natural wetlands, but classification should also be applicable to wetlands which are not natural. This latter objective has long been recognised by scientists engaged in avifauna research and conservation, because very often avifauna will use disturbed and/or constructed habitats. However, other researchers, ecologists, botanists, naturalists, educators and land managers have not been so ready to embrace these habitats, particularly when there are still relatively pristine wetlands that remain unprotected. With the mounting risk of losing rare and endangered flora and fauna if constructed or altered wet habitats are not included in national inventories and definitions of wetland, wetland scientists are being forced to address these wetland types and to discuss their classification. It is possible to recognise anthropogenically altered or constructed wetlands as a single category (Odum et al 1974), and many wetland definitions while including the term “artificial” do not extend beyond this, but as these non-natural wetland types increase in number, it may demonstrate foresight to consider alternate classification procedures.

In this context, a classification of the anthropogenically created or altered wet environments is proposed here. However, these wet environments pose a particular problem in definition, because while there are a large number of clearly contructed and artificially created wet environments, many of the anthropogenically artificial, modified and managed wet environments grade into natural wetlands presenting specific questions as to where to draw the line between “natural” and increasingly “not-natural”. This is particularly difficult if only one attribute of a “natural” wetland is modified, altered, or perturbated. For istance, a wetland altered hydrochemically (a high nutrient content), with consequent changes in the benthic fauna and emergent vegetation, may remain unchanged in its primary class andother functions. In terms of the boundary position between “natural” and artificial/modified, we consider that pristine unaltered wetlands axiomatically are “natural”. The wetland is still considered to be “natural”, if disturbances have taken place but such changes are reversible in the short term. Examples of short term reversible changes are: changes to vegetation such as weed infestation, species reduction due to the incidence of fire, and dumping of rubbish.

83 Some wet environments are not included in the category of anthropogenically created or altered wetlands. These include tailings dams of, say, NaOH, derived from bauxite processing operations, or acid filled holding ponds (e.g., open ponds of Fe-enriched sulphuric acid, pH 0.1, and Fe 6000 ppm, derived from ilmenite processing operations). These types of wet environments do not replicate natural wetlands, and in this context we restrict the phrase “anthropogenically constructed, artificial, modified, and managed wetlands” to those wet environments that duplicate natural wetlands in terms of extent of wetness, or hydrochemistry, or use by biota, i.e., they have natural wetland functions with respect to landscape, hydrology, hydrochemistry, vegetation and fauna.

Most of the anthropogenically created or altered wetlands have been developed for specific purposes, such as water resources (small to large dams), food sources (inland and coastal fish ponds), drainage channels (to dewater area), irrigation channels (to supply agriculture), access (coastal to inland canals), energy sources (hydroelectric schemes), ornamental purposes (golf courses, fish ponds), discharge of effluent waters (tailing dams; seepage ponds, nutrient absorption ponds), and aesthetics (ornamental lakes). On the other hand, some wetland formation was unintended and is the consequence of a rising water table.

The approach to classifying anthropogenically created or altered wetlands, as proposed here, is to focus on the features of land and water that are perturbated to create the wet environment. Similar to the approach adopted in the geomorphic-hydrological classification of natural wetlands, presented in Section 5.0, landscape and water are viewed as the foundation of these wetlands, and hence the same core terms as the natural wetlands are employed but with an appropriate set of adjectival descriptors to address the extent of alteration. This is because, apart from wholly constructed wetlands and extremely geomorphically modified preexisting wetlands, other altered wetlands commonly are developed on a template of a pre-existing natural wetland, with vestiges or the framework of the original wetland still apparent. But even for the constructed wetlands, the resulting wetlands commonly duplicate the landscape and hydrology of a natural system.

7.2 The primary set of descriptors After the core term in classifying anthropogenically created or altered wetlands has been established, the approach then is to focus on the extent that land and water have been perturbated to create the wet environment. Effectively, there can be extreme modification of land, or water, or both, grading to minor modification of land, or water, or both. Wetlands that are not natural, no longer natural, or do not function naturally are classified using the four-fold subdivision as follows:

1. Constructed wetlands 2. Artificial wetlands 3. Modified wetlands 4. Managed wetlands

84 The categories are explained in the Table below.

2nd tier Description Examples Constructe wet lands created where there were wholly constructed environments, created d none before by excavation (basins, drains, ponds, dams) Artificial wet lands alienated or modified by lake to dampland by dewatering, and vice change in hydrology or landscape to versa by rising water levels (due to change their core geomorphic- clearing of vegetation); river or creek is hydrological classification locally changed to a “lake” by damming; lake becomes a dampland by sediment filling, or vice versa by dredging; draining of palusplain to create a drier environment Modified anthropogenic modification of wetlands freshwater lake changes to saline lake such that their hydrochemistry, soils, or biota are altered but not their core geomorphic and hydrological attributes, hence their core classification category remains intact, resulting only in alteration of the adjectival descriptors Managed management of existing wetlands such sumpland with a temporally asymmetric that their hydroperiod is fundamentally hydroperiod becomes a sumpland with a changed symmetric hydroperiod; or a high tidal flat with saltmarsh has its tidal inundation dampened

Thus, while the geomorphic-hydrologic site-specific wetland classification forms the core of the classification of constructed, artificial/modified and managed wetlands, the next level of subdivision is the extent of alteration.

Some of the perturbations to landscape and to hydrological regime will result in alteration of the core wetland classification of an existing wetland (e.g., sumpland altered to lake; or lake to dampland), and these would be classed as artificial anthropogenic wetlands. Perturbations to existing wetlands in terms of their soils, hydrochemistry, vegetation and fauna which does not affect the core classification of fundamental unit will alter the adjectival descriptors. For instance, a saline lake can be created from a freshwater lake. Finally, those wetlands that are managed as to hydroperiod can be termed, for example, managed lake, managed sumpland, managed floodplain, managed saltmarsh-vegetated tidal flat.

Examples of the types of modifications of land and water in land-based and coastal environments are outlined in the Table below. Note that for some of the categories that do not involve extreme modification, the anthropogenically induced change can be reversed.

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Type of modification Examples Status Land-based, with anthropogenic activities effected on dryland extreme land modification: dam excavation in dryland environment to constructed excavation create water body extreme land modification: constructed wetland as nutrient pond constructed excavation extreme land modification: constructed wetland as ornamental lake constructed excavation extreme land modification: construction of fish pond systems within constructed excavation of fish ponds (Type 1: dryland environment dryland based) extreme water modification: rising extensive development of wet salt flats due constructed saline water table due to clearing to rising saline water table extreme land modification: clearing extensive development of wet flats and constructed for agriculture, industry, basins due to rising water table urbanisation Land-based, with anthropogenic activities effected on preexisting wetlands extreme land modification: construction of fish pond systems within artificial excavation of fish ponds (Type 2: preexisting wetland environment wetland based) extreme land and water construction of dam across river valley (a artificial modification: damming of river preexisting wetland) to create water body extreme land modification: clearing wetland environment still remains, though artificial wetlands for agriculture pedogenically and biotically extremely modified extreme water modification: wetland environment still remains, though artificial abstraction of groundwater much drier because of fall in regional water regionally for consumption, table agriculture, industry extreme land and water wetland environment still remains, though artificial modification: clearing and draining hydrologically, pedogenically and biotically of wetlands for agriculture extremely modified moderate land modification: alteration of river banks by walls, such that modified revetting of river banks riparian habitats are lost, but with the main flow and functions of the channels still operating moderate water modification: rising rising water results in local wetlands with artificial water table due to clearing modified water regime (e.g., more frequent /modified inundation) moderate land and water wetland environment still remains, but with artificial modification: use of wetland as a local sediment plumes, and hydrologic, /modified drainage basin for run-off pedogenic and biotic modification moderate to minor water overall wetland environment and functions modified modification: nutrient enrichment still remain, but with altered nutrient content

86 so that benthic fauna and emergent vegetation adjusts moderate to minor water wetland environment still remains, but with, modified modification: alteration of say, more saline, or more nutrient-enriched hydrochemistry waters moderate to minor water wetland environment still remains, but with managed modification: management of altered hydroperiod becase of topping up of hydroperiod water levels moderate to minor water wetland environment still remains, but with managed modification: dischargingwaste altered hydroperiod becase of discharge of water urban or industrial waste water Coastal, with anthropogenic activities initially effected on nearby dryland extreme land and water construction of coastal canal systems for constructed modification: excavation of canals small boat harbours and water-based residential estates extreme land and water construction of coastal fish or prawn pond constructed modification: excavation of fish or systems prawn ponds Coastal, with anthropogenic activities effected on preexisting wetlands extreme land and water construction of coastal fish or prawn pond artificial modification: excavation of fish or systems prawn ponds extreme land and water construction of dam across tidal creek to artificial modification: barring of tidal creek create water body and evaporation ponds for and creation of walls salt production extreme land and water construction of dam across tidal creek to artificial modification: barring of tidal creek create water body to drive tidal-power and creation of walls hydroelectric schemes moderate water modification: construction of locks to control water flow in managed control of flooding in coastal the tidal creek wetlands inhabited by saltmarshes

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7.2 The secondary set of descriptors Further subdivision and discrimination between types of constructed, artificial, modified, and managed wetlands is achieved through the use of landform, water, soil, and vegetation descriptors as outlined in Section 5.0 to describe natural wetland size, shape, salinity, etc. In some instances, where the disturbance has been extreme and permanent, terms such as “cleared”, “pedogenically disrupted”, “mined”, “nutrient enriched”, “eutrophic”, or “drained” can be added as a descriptor to convey the particular type of anthropogenic impact.

Also, since constructed, artificial, modified, and managed wetlands commonly have an anthropogenic function, it is worthwhile to add this to the nomenclature. The list of engineering and agricultural technical terms for these wetlands is extensive, and terms such as dams, ponds, fish ponds, solar salt ponds, evaporation ponds, evaporation basins, floodways, canals, drains, irrigation ditches, irrigation canals, drainage ditches, convey the function of these wetlands, and if necessary can be added as a bracketed suffix.

7.3 Examples of constructed, artificial, modified, and managed wetlands To illustrate the use of the classification, some practical examples are provided drawn from around the world, but focused on examples in Western Australia. Examples of artificial and modified wetlands include the Swiss Lakes Thunersee, Oschinensee, Bachalpsee, rivers with locks along them, drained estuarine flats (Camargue), drained blanket bogs (Pennines, UK), excavated wetland basins, wetlands with added drainage input, wetlands which are mowed, wetlands with controlled water levels, cemented channels, wetlands experiencing increased sediment loads, wetlands which are experiencing nutrient enrichment (Lake Burdur Golu, Turkey), wetlands whose water source has been diverted (Zambeze Delta, South Africa). Examples of large water bodies that are anthropogenic include Lake Argyle in northern Australia, Gatun Lake in Panama, the Trebon fishponds of the Southern Bohemia, and the aquaculture ponds of southeast Asia.

The classification of a range of wetlands is presented in the Table below, drawing largely on Australian examples.

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Location Description Classification Full classification (function in brackets) Lake Argyle, large dam on preexisting creek and artificial anthropogenic artificial freshwater lake (dam) Western Australia river system; water storage for freshwater lake irrigation Warragamba Dam, large dam on preexisting creek and artificial anthropogenic artificial freshwater lake (dam) New South Wales, river system; water storage for freshwater lake Australia human consumption Gatun Argyle, large lake on preexisting river artificial anthropogenic artificial freshwater lake (navigation Panama system; designed for vaigation freshwater lake access) Karratha, large permanent marine saline and artificial anthropogenic artificial hypersaline lake (solar salt Western Australia hydrsaline water areas created by hypersaline lake production holding pond) damming tidal creek and pumping water into large holding “ponds” on a preexisting high tidal flat; evaporation ponds for solar salt production Geographe Bay, small scale estuaries and rivers managed river managed river Western Australia with locks

Balcatta, former sumpland wetland basin artificial anthropogenic artificial lake Swan Coastal Plain, excavated of its peat; uee of peat ad lake (ornamental lake) Western Australia subsequent development of urban ornamental lake Lake Forrestdale, wetlands with added drainage modified lake modified lake Swan Coastal Plain, input; unintended contamination of Western Australia water by inappropriate landuses Lake Bibra, wetlands with added drainage modified lake modified lake

89 Swan Coastal Plain, input; unintended contamination of Western Australia water by inappropriate landuses Lake Claremont, former sumpland now artificial anthropogenic artificial lake Swan Coastal Plain, permananenly inundated because of lake Western Australia water table rise due to clearing Lake , dammed natural drainage valley artificial anthropogenic artificial lake Zurich, Switzerland and river lake river adjoining Zurichsee, cemented channel wall modified river modified river Zurich, Switzerland

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7.6 Discussion The procedure we suggest here is to address the grade from wholly constructed wetlands through to artificial/modified and managed wetlands and design a classification that mirrors the classification of natural wetlands. In this context, as noted earlier, apart from constructed wetlands, natural wetlands once formed the template to the currently artificial/modified and managed wetlands, and so it would seem logical to classify these latter wetlands using same the natural categories and provide adjectival descriptors as prefixes to denote the extent of alteration. In this manner, the full range of descriptors used in natural classifications of site specific wetlands are transferable to the artificial/modified and managed wetlands, and with the use of an adjunct term denoting extent of alteration, provide a robust classification of these altered and constructed wetlands. This approach, we believe, provides a powerful conceptual link between the classification of natural wetlands and the enormous number of constructed, artificial, modified and managed wetlands of the world. It also allows the history to be traced of the natural system that has progressed, or may still be progressing to an anthropogenic system without a major disjunction in classification.

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97

98 Scope of wetlands: land-based, and where the landmass is wetted by the sea

LAND SEA

Hydrological settings and/or processes: 1. rainfall LANDMASS MARGIN WETTED BY 2. perching LANDMASS WETTED BY A RANGE OF TERRESTRIAL PROCESSES 3. run-off COASTAL PROCESSES 4. seepage/springs rainfall rainfall 5. artesian upwelling rainfall 6. groundwater intersection rainfall e

7. marine (wave & tidal) wetting p o l s

d g n d in a n l r

t u o p e s run-off m / w d n e perched wetland flats, a g tl a wetland plains, and basins e p w e se wetting of margins of the landmass by

channels marine waters highwater groundwater channels channel fill intersection capped by

wetland mound s

lowwater d n a l t

artesian e w

upwelling l a t artesian s a o

upwelling c

not to scale, and exaggerated vertical scale Fig. 1.1: Conceptual diagram illustrating the scope of wetlands as land-based wet environments, generated by a variety of hydrological processes on land, and the wetting of land masses by the sea A

DELTAS

ESTUARIES

SUBMARINE ENVIRONMENTS COASTAL WETLANDS INLAND WETLANDS B

GEOMORPHIC/HYDROLOGIC SYSTEM SALINITY CLOSED OPEN highlands, freshwater slopes, basins vales channels flats mixed or and alternating deltas, estuaries flats open coasts marine

INLAND WETLANDS COASTAL WETLANDS Fig. 1.2: Schematic diagram showing the scope of wetlands in terms of inland versus coastal setting, and the relationship of inland wetlands, coastal wetlands (open, estuarine, deltaic) geomorphically, hydrologically, and hydrochemically (salinity) BASINS thickly filled parent surface thinly filled mounded with sediment with sediment

increasing sediment fill CHANNELS & VALES thickly filled parent surface thinly filled mounded with sediment with sediment

increasing sediment fill

FLATS (& PLAINS) surface-parallel accretion parent surface accretion mounded accretion

SLOPE surface-parallel to wedging accretion parent surface accretion

mounded accretion

HILLS, HIGHLANDS thinly mounded parent accreted (thickly surface accreted)

increasing accretion

Fig. 1.3: Stages in the accretion, filling, or mounding of wetland sediments, soils, precipitates, and biogenic deposits in lowland, basins, slopes and highlands. Terminolgy for the various stages is: 1. parent surface; 2. filled; and 3. mounded. DRY AND INTERMEDIATE CLIMATES

discontinuous negligible, thin to thick deposits within and on wetlands that results from juxtaposition of contiguous landforms

HILLS, HIGHLANDS FLATS (& PLAINS)

CHANNELS & VALES CHANNELS & VALES BASINS CHANNELS & VALES BASINS WET CLIMATES

thinning and thickening of a continuous "sheet" of peat formed by juxtaposition of contiguous landforms

HILLS, HIGHLANDS SLOPES

FLATS (& PLAINS) CHANNELS & VALES BASINS Fig. 1.4: Combinations of landforms, as they would occur naturally in juxtaposition, with various stages of accretion, filling, or mounding of wetland sediments, soils, precipitates, and biogenic deposits to generate the majority of wetland systems documented globally. A dry to intermedimate climate setting is contrasted with a wet climate setting. < 8 ha, < 2 m < 8 ha, > 2 m pond (?deep) pond a e r a e c a f r u s n i e s a

e > 8 ha, > 2 m r c lake n i

increase in depth of water

Fig. 2.1: Range of water filled basins, varying in depth and area, that are allocated different names by wetland classifications (ponds being water bodies < 8 ha in area and < 2 m deep, and lakes being water bodies > 8 ha in area and > 2 m deep). Some of the water bodies are not allocated names under current classification schemes A: Water-filled basin in the landscape, showing water regime zones, and vegetation B: Compartmentalisation of the basin into zone based on water levels and hygrophilic vegetation

UPLAND WATER FILLED BASIN UPLAND UPLAND LACUSTRINE PALUSTRINE UPLAND

LITTORAL LIMNETIC LITTORAL D D D D N

E T E N T A T T D D N D D L A A A E E N E E T N L T T D E B B D E T I E S I A

M S T I L E L L E R S W S I C C O T

I I R O W T S O R O T E T T

S T S E R O T H A A N N W F E P N S O E N U U P B E N O O G Q Q N C G O R C A A O E R N N N E N U U M E M E

HIGH WATER a HIGH WATER a b b a

AVERAGE WATER a

- c c

- b b T

T E

d

d - E c - M

LOW WATER LOW WATER M c S

S

2 m e - P E

e E

d P - d S A O A

O S E

- S S - R E M

e e

O I R O I M A N

N

A I - - N P N R T

I T I P R I E E N A I N E A L R E I R R Y L T L T L R M Y M E M L E

L F M Y

R Y R F I A L I T

M

T M L O F A T F N T O L E L E I N I O O T E T N O O N T T E N D O T E E O T N D L T N N L E Y D L T Y D E D Y T T L

D

E F L E Y L

F Y F D L Y D

L O L F

O E E O L O X X O O O P P D O D O O D E E D E S D S D E E D E D D D

C: Approach in this study to identifying zones in a water-filled basin with ponded water D: Approach in this study to identifying zones in a water-filled basin that intersects the watertable (without zone of capillary rise) (with zone of capillary rise)

WETLAND BASIN: WETLAND BASIN: UPLAND with concentric zones of wetness UPLAND UPLAND with concentric zones of wetness UPLAND

permanently inundated seasonally inundated, permanently inundated seasonally inundated, d

seasonally inundated, e seasonally inundated, d g with or without vegetation with zones of vegetation e with zones of vegetation with or without vegetation with zones of vegetation g with zones of vegetation g o g l r o l e r t e t a a w

w y

l l y l l a a n n o s o s a a e s e s

HIGH WATER HIGH WATER

LOW WATER LOW WATER

Fig. 2.2: A. Cross-section of a wetland basin showing the various depths of water, continuity of the land, and distribution of biotic zones. B. Compartmentalisation of the continuum of land and water (modified after Cowardin et al 1979). C. Recognition that the cross-section represents a continuum of land and water suggested in this study, with the basin ponding water D. Recognition that the cross-section represents a continuum of land and water suggested in this study, with the basin intersecting the watertable A: Compartmentalisation of the basin into zones based on water levels and hygrophilic vegetation (cross section and classification of compartments as in Fig. 2.2B)

ENTIRE WATER FILLED BASIN IS NOT VIEWED AS A WETLAND, BUT ONLY LITTORAL ZONES AND ESPECIALLY THOSE WITH VEGETATION (AS MARKED)

WETLAND WETLAND

LACUSTRINE PALUSTRINE

LITTORAL LIMNETIC LITTORAL

D D D D D D E E E N N D D N T T T T T E E A S A A A N A N L B B L E L E

T D E D T T I M T R I E T E E L E C C S L I I S I R O O I T T W S T O W F W O S

O

T A A S R S T R T H E U U N O E N N S N P B E P Q Q E O O N N A A G C G C O R O R N N E N E N U U M M E E

a HIGH WATER a b b a

AVERAGE WATER a

- c c

- b b T

T E

d

d - E c - M

LOW WATER M c S

S

2 m e - P E

e E

d P - d S A O A

O S E

- S S - R E M

e e

O I R O I M A N

N

A I - - N P N R T

I T I P R I E E N A I N E A L R E I R R Y L T L T L R M Y M E M L E

L F M Y

R Y R F I A L I T

M

T M L O F A T F N T O L E L E I N I O O T E T N O O N T T E N D O T E E O T N D L T N N L E Y D L T Y D E D Y T T L

D

E F L E Y L

F Y F D L Y D

L O L F

O E E O L O X X O O O P P D O D O O D E E D E S D S D E E D E D D D

B: Approach in this study to identifying zones in a water-filled basin that intersects the watertable (cross section as in Fig. 2.2D))

ENTIRE WATER FILLED BASIN IS A WETLAND, WITH ZONES OF PERMANANENT AND SEASONAL INUNDATION, AND OUTER ZONE OF SEASONAL WATERLOGGING

WETLAND

seasonally inundated to permanently inundated seasonally inundated to seasonally waterlogged, with or without vegetation seasonally waterlogged, with zones of vegetation with zones of vegetation

HIGH WATER

LOW WATER ZONE OF ZONE OF SEASONAL SEASONAL WATERLOGGING WATERLOGGING

Fig. 2.3: Annotated comparison between this study and Cowardin et al (1979) concept of lacustrine and palustrine wetlands, showing (A) location of wetland along margins of basin, and the compartmentalisation of the basin into lacustrine and palustrine zones at the primary level, and (B) the idea that the entire basin is a wetland with vegetation along its periphery WETLAND BASIN LOW IN THE LANDSCAPE: SIMILAR WETLAND BASIN HIGHER IN THE LANDSCAPE: SIMILAR WETLAND BASIN HIGH IN THE LANDSCAPE: with full development of concentric zones of wetness with development of two concentric zones of wetness with development only of seasonal waterlogging as a zone of wetness (permanently inundated, seasonally inundated, seasonally waterlogged) (seasonally inundated, seasonally waterlogged)

seasonally inundated seasonally inundated to seasonally inundated to outer zone of seasonally waterlogged seasonally waterlogged, permanently inundated seasonally waterlogged, seasonally waterlogged with or without vegetation with zones of vegetation with or without vegetation with zones of vegetation with or without vegetation

HIGH WATER TABLE LEVEL

LOW WATER TABLE LEVEL

Fig. 2.4: The basin wetland shown in Figures 2.2-2.3 redrawn to show them occurring in an undulating landscape at various topographic levels. In this instance, these depressions in the landscape intersect a regional watertable which generates wetland basins with various depths of water. The gradation of wetland basin types is from permanenly filled, to seasonally filled to seasonally waterlogged PERMANENTLY INUNDATED ZONE

SEASONALLY INUNDATED ZONE

SEASONALLY WATERLOGGED ZONE BOUNDARY OF WETLAND

Fig. 2.5: Position of a wetland boundary encompassing all zones of wetness, i.e., permanent inundation, seasonal inundation, and waterlogging (after C.A. Semeniuk 1987) called different types of wetlands

A

not called permanent water a wetland > 8 ha, > 2 m deep

B

R TE D A D N T N A W A L P IT A T E B TL E E A E W D H W , , d d : : n n d d a a l n l n d t d e d t r a n a m l e n m n l e

t

o t a a 2 l a w 2 l e l h w

e t

t

t s t t >

e w >

e w e

n

r n f d r f w e w w

e e e o e

o t

t t t g t

d g r r a e n n a a e e e e t g e e w d g w i s

l

g r d m g r d m e r r o r e e o e e o s e e

B o A n f m m o e e c n u

Fig. 2.6: Annotated map of typical wetland showing distribution of various water and vegetated zones, and cross-section showing terminology of the zones of Cowardin et al (1979) 1. steady water level above, at, and shallowly below ground level

2. seasonally fluctuating water levels: permanently above the surface, intersecting the ground, and wetting the ground-surface seasonally (humid settings, annual rain)

3. seasonally fluctuating water levels (as above), but with a longer term climate-induced decline in water levels, to be followed by a later increase (semiarid settings, annual rain)

4. seasonally fluctuating water levels, with an aperiodic above average increase in water levels (arid settings, annual rain, aperiodic cyclones)

5. no prevailing or annual surface water, with aperiodic input by cyclones (solid line), or long-term falling water table with aperiodic surface water from cyclones (dashed line) (arid settings)) rapid input rapid input rapid run-off rapid input slow discharge 5-10 years slow discharge

long-term falling water table KEY: ground surface annual hydrological cycle stratigraphic profile

time Fig. 2.7: Annotated typical graphs of hydroperiods for surface water and the water table in various climatic and hydrologic settings. Hydrographs of water tables, if appropriate, are presented coupled with associated surface water A

downstream change from conistent channel to a chain of "lakes"

B

wet season flow dry season along a continuous segmentation further dry season channel of valley tract effect: chain into channel sections of "lakes", separated and "lakes" by dry segments of channel

Fig. 2.8: Lotic and lentic wetlands illustrating spatial and temporal gradation. A: channel system that changes down stream into a series of "lakes" B: channel that changes to a chain of "lakes" during the dry season A: DEVELOPMENTAL HISTORY OF A MINERAL MOUND SPRING

STAGE !; STAGE 2: STAGE 3: STAGE 4: small wetland small wetland larger mound large mound developed on mound developed developed with developed with plain as a result as mineral precipitates ongoing mineral ongoing mineral of water seeping accrete accretion; pond accretion; pond from artesian spring developed on developed on crest crest of mound of mound (A), and redirection of water in the subsurface of the mound creates additional seepage points on the slope (B, C) A

C B g g g g n n n n i i i i l l l l l l l l e e e e w w w w p p p p u u u u

n n n n a a a a i i i i s s s s e e e e t t t t r r r r a a a a

B. PLAN VIEWS OF THE MINERAL MOUND SPRING AT EACH STAGE

C

D A

B

(explanation of units A, B, C, D in text) Fig. 2.9: Growth of a "mound spring" from a site of artesian upwelling, and plan view of mound showing heterogeneity in the array of its various internal landforms and water regimes. A s l e

open channel n n a h c

d n u o r g r e d

partly occluded n u

o t

channel s l e n n a h c

n e p o underground m o

channel r f

n o i t a d a r g

B doline cave exposing the water table

stygofauna basin intersecting C at water table the water table: wetland 3

t o

>

1 0

m water table zone of capillary rise, the water table, and the phreatic zone: wet subsurface but not a "wet" land

Fig. 2.10: Some problems in the concept of a wetland. A: allocation of undergound water-filled channels to realm of wetlands because of their continuity with open channels. B: Caves as underground "lakes" (i.e., underground "wetlands), and the fact that such cave water bodies may become exposed through development of dolines to become true wetlands. C: the intersection of the water table by a basin to develop a true wetland, and the incorrect allocation of the wet subsubsurface to the realm of wetland. 1. Hydrologic boundary high water boundary (encompassing zone of capillary rise)

low water boundary

2. Pedologic boundary

richly wetland peat humic soil boundary substrates substrates

3. Macrophytic vegetation boundary

zoned or mosaic vegetation wetland boundary

Fig. 3.1: The boundary of a wetland determined by hydrology, pedology (soils), or vegetation. VERTICAL VIEW PLAN VIEW

vertical walls no change to boundary fluctuating water level

high water boundary

inclined walls

fluctuating water level

low water boundary

Fig. 3.2: Theoretical wetland: rock wall lake with no capillary rise, and the effect of fluctuating water level on wetland boundary. A. Sand-walled wetland, with moderately steep walls, fluctuating water levels and zone of capillary rise

capillary rise

fluctuating water level

inclined walls low water boundary

high water boundary outer boundary of wet soil B. Sand-walled wetland, with low sloping walls, fluctuating water levels and zone of capillary rise

capillary rise fluctuating water level

inclined walls

low water boundary high water boundary outer boundary of wet soil C. Muddy-sand walled wetland, with low sloping walls, fluctuating water levels and zone of capillary rise

capillary rise

fluctuating water level inclined walls

low water boundary high water boundary outer boundary of wet soil Fig. 3.3: Theoretical wetlands: sandy or muddy floor, with capillary rise, and the effect of fluctuating water level on wetland boundary. A PERMANENTLY INUNDATED ZONE

SEASONALLY INUNDATED ZONE

SEASONALLY WATERLOGGED ZONE BOUNDARY OF WETLAND

The basin is permanently The basin is The basin is B inundated, and has seasonally inundated, seasonally seasonally inundated and has seasonally waterlogged and waterlogged margins waterlogged margins

CAPILLARY RISE & WATERLOGGING LANDSURFACE

HIGH WATER

LOW WATER

SEASONAL WATER LEVEL FLUCTUATION

Fig. 3.4: Relationship of wetland boundaries to zones of inundation, and to zones of waterlogging (after C.A. Semeniuk 1987) Criteria for boundary. 1. edge of waterlogging, and/or 2. edge of wetland soil, and/or 3. edge of wetland vegetation

permanently inundated seasonally seasonally seasonally inundated seasonally inundated seasonally waterlogged waterlogged waterlogged

Basin with permanently inundated Basin with seasonally inundated Basin with core of seasonally centre, surrounded by seasonally centre, surrounded by seasonally waterlogged terrain. inundated periphery and by waterlogged outer zone. seasonally waterlogged outer zone. Fig. 3-5: Criteria for boundary of three types of wetland basins, with diagnostic "wetness" in zones within the wetlands. A Fully vegetated wetland plain 20 km boundary of wetland plain

full extent of wetland plain B Wetland plain with areas of remnant vegetation boundary of wetland plain sharp boundary

diffuse boundary

boundary of remnant vegetation remnant areas of vegetation within wetland plain Fig. 3.7: Boundaries around and within wetland plains. A. Extent of a fully vegetated wetland plain and its boundary. B. Extent of a wetland plain that has been alienated, with remnant patches of vegetation. The boundary of the wetland plain remains as in (A) Asymmetric development Circumferential development of beachridges of beachridges a a c c c c r e r e t i t o i o n n

o

o f

f b

b e e a a

original single simple wetland basin original single simple wetland basin c c h h with simple margin with simple margin r i r d i d g g e e s

s c

a i r c s y u m m m f e e r e t r n i c t a i a l l l y l y

a

a l o l o n n g g

m

m a a r r g g i n i n

wetland basin with complex margins wetland basin with complex margins and asymmetrically ringed by shore-parallel and circumferentially ringed by shore-parallel smaller secondary basins behind beachridges smaller secondary basins behind beachridges Fig. 3.8: Change from a single basins with simple margins to more complex forms with beachridge margins, and a ring of smaller wetland basins developed behind the beachridges wetland boundaries

3 wetlands with merged boundaries, vegetation intact

500 m wetland boundary

a single wetland with undulating floor and 3 locations of permanent "wetness"

500 m

Fig. 3.9: Wetland boundary where three separate wetlands merge compared to a single wetland that has an undulating floor and develops three locations of more permanent "wetness", but where these centres account for < 15% of the wetland area. seasonally seasonally waterlogged inundated wetland zone zone boundaries

3 discrete, separate wetlands wetland boundary

wetland boundaries 3 discrete, separate wetlands

wetland boundaries

3 wetlands with merged boundaries

Fig. 3.10: The location of wetland boundaries as three discrete separate wetlands merge. Note the wettest part of the wetland (the wet centre) comprises > 15% of the wetland area. wetland boundaries

3 wetlands with A A A merged boundaries, A cleared of vegetation (alienated) A A

= alienated 500 m A

wetland boundary

a single wetland A A (alienated) with A undulating floor A and 3 locations of permanent A A "wetness"

A = alienated Fig. 3.11: Wetland boundaries: comparing three merged wetland basins with a single wetland that has an undulating floor and develops three locations of more permanent "wetness", but where these centres account for < 15% of the wetland area. The alienation within each of these wetland situations does not affect the location of the boundary of merged or single wetland. 1. Simple basin wetlands with steep boundary 3. Multiple basin wetlands with steep boundary (from Quindalup, Spearwood, or Bassendean setting) (mainly from Spearwood setting)

2. Simple basin wetlands with low-gradient boundary 4. Multiple basin wetlands with low-gradient boundary (from Quindalup, Spearwood, or Bassendean setting) (mainly from Bassendean setting)

5. Complex basin wetlands with steep boundaries 6. Complex basin wetlands with low-gradient boundary (mainly from Spearwood setting) (mainly from Bassendean and Pinjarra setting)

7. Rivers, creeks, seasonally flooded/waterlogged plains (mainly from riverine plain setting of the Pinjarra Plain)

river or creek

seasonally seasonally flooded plain waterlogged plain

Fig. 3.12: Boundaries of various wetlands in different geomorphic settings, with steep, varying to low-gradient boundaries (geomorphic settings are examples from the Swan Coastal Plain, Western Australia (Semeniuk 1987) wetland boundary

A A A A

wetland because wetland because wetland because wetland because wetland because it is "wet" land it is "wet" land it is "wet" land it is "wet" land it is "wet" land

increasing alienation with loss of natural vegetation

natural vegetation

Alienation (e.g., clearing of vegetation, A or disruption of soil, etc.) Fig. 3.13: The effect of increasing alienation of a wetland: the boundary does not change. Boundary of wetland with intact native vegetation

Boundary of wetland with permanently disturbed vegetation

Boundary of wetland with partly disturbed vegetation

disturbed vegetation

Boundary of wetland with a revegetating system disturbed revegetation of vegetation disturbance area

Fig. 3.14: Boundary of wetland with intact native vegetation, permanently disturbed vegetation over the whole wetland, partly disturbed vegetation, and a revegetating system B C A B: co Fig seasonally waterlogged Riv m . 3 wetland plain native vegetation Basin withintact intact nativevegetation Channel, andflatswith pa .15 er flooded plain ine re

: B channel

d flooded plain a ou Wetland seasonally to nd waterlogged th nd wetland plain fla os ar BOUNDARY OFTHEV Fully vegetatedwetlandp plain withareasofremnan ts e y o se BOUNDARY OFWETLAND wi re fu f w m ll WETLAND UNITS ttin th e n xt a p et e n g. 2 n t 0 or la t a k o C re m f w nd tio a .W s e o ns s w tla f v et ARIOUS n a e d g ith la p lie e ta la nd in in lain na tio t vegetation p ta n alienated vegetation Basin withpatchesof te la ct patches ofalienvegetation Channel, andflatswith d. in n A at se

: B seasonally re wi ive ttin waterlogged m th as bo na wetland plain in we ve nt un g. in ve

da flooded plain wetland plain Boundary of tla wetland plain Boundary of ge nd ry se ge channel of ta p flooded plain tio la ttin in ta n seasonally waterlogged tio g. wetland plain n 1. Hydrologic boundary with decadal climatic fluctuation: boundary migrates WRC-06.CDR

wetland boundary

wetland zone of inundation expansion of boundary contraction of boundary and waterlogging with water table rise with water table fall wet phases dry phases 2. Pedogenic boundary with decadal climatic fluctuation: boundary largely stays the same wetland hydrologic boundary boundary

zone of hydric soil

boundary of hydric boundary of hydric boundary of hydric soil soil extends beyond soil coincides with does not coincide with hydrologic boundary hydrologic boundary contracted hydrologic boundary

3. Macrophytic vegetation boundary with decadal climatic fluctuation: boundary largely stays the same

wetland hydrologic boundary boundary

zone of peripheral macrophytic vegetation boundary of peripheral boundary of peripheral boundary of peripheral macrophytic macrophytic vegetation extends macrophytic vegetation coincides vegetation does not coincide with beyond hydrologic boundary with hydrologic boundary contracted hydrologic boundary Fig. 3.16: Boundary of a wetland using hydrologic, pedologic, and vegetation features: boundary changing in response to decaded climate fluctuations. Fig. 5.1: Basic dune forms classified on their geometry (landscape form), after McKee (1979). N G diatomite-dominated in g in basins

S c 10 km a r T p L

U

A

F

G

N

I

L

R

A Swan D Coastal N Plain

large wetlands

Quindalup Dunes

Spearwood Dunes

Bassendean Dunes

Pinjarra Plain peat-dominated basins Darling Plateau

Fig. 5.2: Distribution of the Bassendean Dunes, a relict desert dune terrain, in the central part of the Swan Coastal Plain, here spanning a climate from subhumid to semi-arid. Small wetlands not shown at this scale. Basins to north are diatomite-dominated, to south are peat-dominated Irregular shaped domain of a Fan-shaped domain of a consanguineous wetland suite consanguineous wetland suite

Range of wetland basin types and sizes characterising this particular wetland suite

Fig. 5.3: Idealised diagram showing the range of wetland sizes that needs to be addressed in a site-specific classification and the fact that the domain of a consanguineous wetland is at a larger scale Focus on four subregions: wetlands occurring within a subregion, and along their interfaces

10 km

Focus on one subregion outlining its three consanguineous suites Suite 1

N

Suite 2 10 km

Suite 3

10 km

Focus on one consanguineous suite (suite 3) showing range in size and shape of wetlands S C A R P

Map showing two wetland regions separated by a major scarp (heavy line): to the east of the scarp is a fluvially dissected region; to the west is a region of six longitudinally arrayed subregions

10 km

Focus on individual wetlands within the consanguineous suite 3 showing range in size and shape of wetlands

1000 m

Fig. 5.4: Idealised diagram showing the various scales of observation: from the scale of a wetland region to subregion, to consanguineous suite, to individual wetland, which themselves are variable in size A MEGASCALE LAKE Note: size of quadrats not to exact scale; indicative only MACROSCALE LAKE

LAKE MESOSCALE LAKE MICROSCALE

LAKE LAKE LEPTOSCALE LAKE M M M L E A E I P C S T C O R O R O S S O C C S C S A A

LAKE C A L L A E E L : : E L

1 E : <

0 : 1

1 0 > 0 0 0 0

1

m m m 0

M

k

x x x m

E

1 1 1 G

0 0 0 x

A 0

0 m 1 0

S 0 m

C m

k

A - m

- 1 L

1 E 0 -

: 0

1

m > 0

k

m 1 x m 0

1

x x k 0

m 1

1 m 0

k 0 x m

m 1 0

k m

Note: size of quadrats not to exact scale; indicative only

B MACROSCALE RIVER MESOSCALE RIVER MICROSCALE R LEPTOSCALE R I V RIVER I RIVER E R V L E E P R T M O I M C S C E R S A O O L S E S C : C

A s M A e L v L E A E e :

C : 1 r

a 1 R 0 0 l s O

m

0 m S s e

C e m t A t r e r e e L t s E s r

e w

: w

s > i

d i

w d 1 e e 0 i d

0 o ,

e 0

r 1

,

l

m 0 e 1 s s 0

/ s w s s ,

e k i s d e i v l o e e v m , e r

a 1 r e a l 0

t k s l r / / i e l 1 o 1 s 0 0 m

s l 0 o

e k s n

i t k l g o r i e l m o s m

e l o t e n r e t g e s s

l

o l o n n g g

Fig. 5.5: Scales of reference to describe the various sizes of wetlands. A: Frames of reference for a permanently inundated basin = lake. B. Frames of reference for a permanently inundated channel = river. Region 1: Region 2: extensive mountainous terrain APPROACH USING dune terrain INCREASING SCALE: SITE-STUDIES PROGRESSIVELY

AGGREGATED INTO Region 3: front-of-mountains LARGER NATURAL comprised of two WETLAND REGION 3: subregions GROUPINGS WITH TWO SUBREGIONS

FOUR WETLAND REGIONS SOUTHERN SUBREGION WITH CONSANGUINEOUS SUITES CLASSIFICATION AT THE LEVEL WETLAND REGION CLASSIFICATION AT THE LEVEL WETLAND REGION CENTRAL CONSANGUINEOUS INTO WETLAND SUBREGIONS SUITE

CLASSIFICATION AT THE LEVEL WETLAND REGION OR SUBREGIONS INTO CONSANGUINEOUS SUITES APPROACH USING SITE-SPECIFIC INDIVIDUAL WETLAND DECREASING SCALE: CLASSIFICATION REGIONAL STUDIES CLASSIFICATION AT THE SITE-SPECIFIC LEVEL: DECREASING DOWN INDIVIDUAL WETLAND CLASSIFIED TO SPECIFIC SITES

Fig. 5.6: Summary idealised diagram showing the principles of the proposed scalar approach to the delineation and classification of wetland systems: from wetland region and wetland subregion, to consanguineous suites, to individual site-specific wetlands DARLING PLATEAU Swan Coastal Plain A PINJARRA PLAIN N SPEARWOOD BASSENDEAN DUNES Darling DUNES Plateau QUINDALUP DUNES D

C E Sea Level

WEST EAST Tamala Limestone Limestone lenses (hills) Guildford Formation in Bassendean Sand

10-1,000 +m

DARLING PLATEAU SWAN COASTAL PLAIN Dandaragan Plateau and Collie Basin

QUINDALUP SPEARWOOD DUNES BASSENDEAN DUNES PINJARRA PLAIN DANDARAGAN PLATEAU DARLING PLATEAU B DUNES YOONGARILLUP PLAIN 34 16 31 13

5,7,8 33

29 35 41 19

32 14

6 17 36 39

27,28 Estuaries 23,24,25,26 20 38

15 11

37 2 1 21

22 40 3 4 9 12 18 10 42 COLLIE BASIN

BASINS AND ESTUARIES PLATEAU BASINS, FLATS, CHANNELS PLATEAU PLAINS CHANNELS CHANNELS AND FLATS Fig. 5.7: A. Geomorphic units of the Swan Coastal Plain and adjoining Plateau (from Semeniuk & Glassford 1989). B. Consanguineous wetland suites of the Swan Coastal Plain and adjoining Plateau. For nomenclature of the suites, see Semeniuk (1988) A Point Peron B

DARLING PLATEAU SWAN COASTAL PLAIN Dandaragan Plateau and Collie Basin Lake QUINDALUP SPEARWOOD DUNES BASSENDEAN DUNES PINJARRA PLAIN DANDARAGAN PLATEAU DARLING PLATEAU Richmond DUNES YOONGARILLUP PLAIN Lake 34 Cooloongup 16 31 13

5,7,8 33

29 35 41 Penguin 19

Island 32 14

6 17 36 39 Warnbro Lake 27,28 Sound Walyungup Estuaries 23,24,25,26 20 38

15 11 Becher Suite 37 2 1 21

Cooloongup Suite 22 Becher 40 Point 3 4 9 12 Peelhurst Suite 18 10 42 COLLIE BASIN 0 1000 BASINS AND ESTUARIES PLATEAU Scale (m) BASINS, FLATS, CHANNELS PLATEAU PLAINS CHANNELS CHANNELS AND FLATS DAMPLANDS SUMPLANDS LAKES HOLOCENE BEACHRIDGE PLAIN PLEISTOCENE LIMESTONE TERRAIN

Cooloongup Suite Madora Becher Suite Bay Peelhurst Suite Fig. 5.8: The three consanguineous wetland suites in the coastal ddunes (Quindalup Dunes). B. Idealised occurrence of the three wetland consanguineous suites in the Quindalup Dunes within the context of the Wetland Region of the Swan Coastal Plain A PERMANENTLY INUNDATED ZONE

SEASONALLY INUNDATED ZONE

SEASONALLY WATERLOGGED ZONE BOUNDARY OF WETLAND

The basin is permanently The basin is The basin is B inundated, and has seasonally inundated, seasonally seasonally inundated and has seasonally waterlogged and waterlogged margins waterlogged margins

LAKE SUMPLAND DAMPLAND CAPILLARY RISE & WATERLOGGING LANDSURFACE

HIGH WATER

LOW WATER

SEASONAL WATER LEVEL FLUCTUATION

Fig. 5.9: Nomenclature of wetland basins with various water regimes, and relationship of wetland boundaries to zones of inundation, and to zones of waterlogging (nomenclature added to zones of Fig. 3.4) Criteria for boundary. 1. edge of waterlogging, and/or 2. edge of wetland soil, and/or 3. edge of wetland vegetation

LAKE SUMPLAND DAMPLAND PIRAPI BASINMIRE

permanently inundated seasonally seasonally seasonally intermittently permanently inundated seasonally inundated seasonally waterlogged waterlogged waterlogged inundated waterlogged

Lake: permanently inundated Sumpland: seasonally inundated Dampland: a core of seasonally Pirapi: a core of intermittently inundated Basinmire: a core of permanently centre, surrounded by seasonally centre, surrounded by seasonally waterlogged terrain terrain ( and outer ring of intermittently waterlogged terrain inundated periphery and by waterlogged outer zone waterlogged terrain) seasonally waterlogged outer zone

Fig. 5.10: Boundary and hydrological characteristics of five types of wetland basins, with diagnostic wetness" zones within the wetlands. (n re F ig la o adjoining flat that is . m ti 5 seasonally waterlogged o .1 e n n 1 s c

: adjoining flat that is h N la palusplain ip seasonally inundated o tu o (flooded) PLAN VIEW m re f e w

a channel permanently or n e c seasonally inundated d

tl floodplain la d a adjoining flat that is tu e n d

d seasonally inundated re river or creek t b (flooded) o o o

z floodplain f u o c n n h adjoining flat that is d e a

a seasonally waterlogged s n palusplain o ri n e e f s F ls t ig a o z . n 3 o d .6 n f e )

la palusplain seasonally seasonally

s palusplain palusplain o ts waterlogged waterlogged w f in it floodplain u h seasonally seasonally VERTICAL VIEW n Sharp boundaries v Diffuse boundary floodplain floodplain

d flooded flooded a a ri ti o channel channel o u creek n seasonally river permanently

s broad channel w , river or creek flooded flooded a a n seasonally seasonally te

d floodplain floodplain low water low water

w flooded flooded r re low water a floodplain g te

im seasonally seasonally rl palusplain palusplain high water high water high water o

e waterlogged waterlogged

g palusplain s , g

a in

n g d WETLAND COMPONENTS FOR USE IN CLASSIFICATION

WET LAND

Permanently Basin inundated Seasonally Channel inundated CRITERIA USED TO Permanently WATER PERMANENCE CROSS-SECTIONAL SHAPE Vale DEVELOP waterlogged PRIMARY WETLAND Seasonally Flat waterlogged CATEGORIES Intermittently Slope inundated Hill-top

Fresh Megascale Subsaline Macroscale Hyposaline WATER SALINITY SIZE Mesoscale Mesosaline Microscale Hypersaline Leptoscale Brine Linear Poikilohaline Elongate

CONSISTENCY OF s n

Irregular i Stasohaline WATER SALINITY s Ovoid a B Round clear water PLAN SHAPE s Straight l black water OPACITY/COLOUR e Sinuous n white water n Anastomosing a h

Irregular C oligotrophic mesotrophic NUTRIENT-ENRICHMENT Peat eutrophic Quartz sand CRITERIA USED TO Carbonate sand DEVELOP Carbonate mud SOILS Diatomite acidic/alkaline WETLAND OTHER SPECIFIC Terrigenous mud aerobic/anoxic DESCRIPTORS HYDROCHEMICAL FEATURES Soda mud Gypseous ombrotrophic Halite (meteoric) minerotrophic Peat-dominated WATER SOURCE artesian Quartz sand-dominated Carbonate sand-dominated magmatic Carbonate mud-dominated STRATIGRAPHY Diatomite-dominated shallow Terrigenous mud-dominated Soda mud-dominated moderately deep deep WATER DEPTH Gypsite-dominated Halite-dominated very deep Peat-dominated Quartz sand-dominated Carbonate sand-dominated slow/static (lentic) thinly filled RATE OF MOVEMENT STRATIGRAPHIC FILL thickly filled fast moving (lotic) mounded

basin-filled annually freezes valley tract or channel (cryoperiodic) ANNUAL FREEZING STRATIGRAPHY vale-filled not frozen plain (no descriptor) slope hill-top

Fig. 5.12: Range of land and water descriptors for the wetland classification (expanded from Semeniuk 1987). Vegetation descriptors in Figs 5.13 & 5.14 VEGETATION COVER

PERIPHERAL MOSAIC COMPLETE

PERIFORM PANIFORM LATIFORM N N O O I I T T A A T T E E G G E E ZONIFORM GRADIFORM CONCENTRIFORM V V

F F O O

N N O O I I T T A A S S I I N N A A G G R R O O

L L A A BACATAFORM HETEROFORM MACULIFORM N N R R E E T T N N I I

KEY Vegetation Zones

Assemblage 1

Water, salina, or Assemblage 2 vegetation free zone Assemblage 3

Fig. 5.13: Classification of vegetation organisation in wetland basins (after Semeniuk et al 1990) Fig. 5.14: Suggested classification of wetland vegetation using both internal organisation and floristics/structure (from Semeniuk et al 1990) A. Suite of very similar wetlands B. Assemblage of two wetland in close proximity types in close proximity, genetically related but of different geometry

Damplands Dampland

Sumpland

C. Assemblage of two wetland types D. Assemblage of two (or three) along single stretches of channels wetland types of similar geometry and origins, and spatially related

Example 1 Example 2 Chain of lakes Chain of lakes sumplands and sumplands and damplands damplands Incised channel

"Pocket" wider valleys

E. Heterogeneous assemblage of F. Heterogeneous assemblage of wetlands with common underlying wetlands with common underlying causative processes causative processes (e.g. fluvial) (e.g. groundwater discharge)

Creeks River Basins

Z o n e Flats

o d f

is

c g h r a o

r u

g

n Creeks

e

d

Basins w

a t

Flats e r

Fig. 5.15: Idealised diagram illustrating criteria for and the range of possible types of wetland assemblages (or associations) that qualify to be termed consanguineous. Scope of coastal wetlands: where the landmass is wetted by the sea

LAND SEA

COASTAL WETLANDS

MARINE WETTED ZONE (GROUNDWATER)

SPLASH ZONE

SWASH ZONE

TIDAL ZONE

high water

low water

not to scale, and exaggerated vertical scale Fig. 6.1: Conceptual diagram illustrating the scope of wetlands as coastal wet environments, generated by a variety of oceanographic processes and the wetting of the land mass by the sea Open (straight) sandy coast Open (straight) rocky coast

10 km 10 km

Barrier coast Embayed coast

10 km

10 km

Coral reef coast Archipelago coast

10 km 10 km

Tidal flat coast Estuarine and deltaic coast

estuarine 10 km

deltaic

10 km

Fig. 6.2: Examples of eight coastal systems. Some of these involve several kilometres of suptratidal and subtidal zones, or deep water Open (straight) sandy coast Open (straight) rocky coast

coastal wetland is the thin, coastal wetland is the shore interface (the beach) thin, shore interface along this coast (the rocky shore) along this coast

10 km 10 km

Barrier coast Embayed coast coastal wetlands are the thin, coastal wetland is the shore interfaces ( beaches, thin, shore interface spits, tidal flats, rocky shores) (the beach) along this coast along this coast

10 km

10 km

Coral reef coast Archipelago coast coastal wetlands are the thin, coastal wetlands are the variety shore interfaces (intertidal coral, of thin, shore interfaces beaches, rocky shores, spits), along this coast and not the subtidal coral, along this coast

10 km 10 km

Estuarine and deltaic coast Tidal flat coast coastal wetlands are the wide coastal wetlands are the wide tidally exposed surfaces and marine tidally exposed surfaces wetted surfaces along these coasts along this coast estuarine

10 km

10 km deltaic

Fig. 6.3: Location of the coastal wetlands, shown as a dark line, occurring as an interface between land and sea in the examples of the eight coastal systems of Fig 6.2 BEACH Traditional sense of the beach: extending from shallow subtidal to the foredune

Coastal wetland sense of the beach

wave splash zone upper limit wave run-up

tidal range ) f s e l e f e i m e l n r n n n u c e o n o

z u d z b r

l m , e h s r r h r a s e a o c d a f b i b

a t , s w t e b s a l u b f s ( FORESHORE BACKSHORE FOREDUNE

ROCKY SHORE Traditional sense of the rocky shore: extending from shallow subtidal to the full height of the cliffs

Coastal wetland sense of the rocky shore

wave splash zone upper limit wave run-up

tidal range f f f h h p f f f i i i l l l c c m c c c n n o

l l l t a e e

r l

a a a l b b

a d d l l d a i i i t t d t a a i - d i t a b r d d t r i i w u t t e b p s - o t l b u u n s w i s u s o l Fig. 6.4: Comparison between traditional concepts in the use of the terms "beach" and "rocky shore", and the narrowing of the meaning of the term specifically when used as a coastal wetland term MEGASCALE MESOSCALE MICROSCALE

beach zones of the beach spit spit

zones of the tidal flat tidal flat

zones of the rocky shore rocky shore

10 - 1 km 1000 - 100 m < 100 m

MEGASCALE TERMS MESOSCALE TERMS MICROSCALE TERMS as descriptors core coastal wetland unit as descriptors

geomorphic unit: beach, zones of the geomorphic unit, tidal flat, strandplain, spit, 1. coastal type based on tide or wave setting, chenier, shoal, tombolo, tidal level, substrate texture, 2. oceanographic setting rocky pavement, rocky shore, 3. climate setting substrate compostion, bouldery shore, alluvial fan, substrate microtopography, tidal creek, tidal lagoon, salinity, biota biostrome, bioherm Fig. 6.5: Various scales of coastal classification and their detail, and their use in the proposed coastal wetland classification OPEN COASTAL t s n a o o i

beach, tidal flat, shoal, tombolo, rocky t c

pavement, rocky shore, bouldery shore a less common: spit, chenier, tidal delta, tidal l n i

creek, tidal lagoon, biostrome, bioherm) - u

though not all at the same coastal location h e t l m i u a w

c c s s c n o a EMBAYED COASTAL r o

i t c t i i n d m e

n d m o i n c d

a ) e

s

beach, tidal flat, shoal, spit, chenier, tombolo, d

e l tidal delta, rocky pavement, rocky shore, l e

bouldery shore, tidal creek, tidal lagoon, r a a alluvial fan, biostrome, bioherm i e c v t s l u l o e f s

h e s d (

ESTUARINE n m y

a t

g t r a

u e y p t n i n x e i

e l e w p beach, tidal flat, spit, chenier, shoal, tombolo, n i o l tidal delta, rocky pavement, rocky shore, r

m

bouldery shore, tidal creek, tidal lagoon, s e

biostrome, bioherm o v d i r r c

a g g w n n i i o s s

DELTAIC t

a a d e e r r n c c e r n n i t i

beach, tidal flat, strandplain, shoal, spit, chenier, tidal delta, rocky pavement, alluvial fan, tidal creek, tidal lagoon

Fig. 6.6: Idealised diagram showing the four megascale coast types, the trend in riverine influence, and listing the mesoscale coastal wetlands within (though not all units are present at the one location) MEGASCALE MESOSCALE MICROSCALE

zones of the tidal flat

tidal flat

1 2 3

MEGASCALE FEATURES MESOSCALE DESIGNATION MICROSCALE FEATURES zones of the tidal flat: 1. low tidal, rippled, terrigenous sand, marine 1. embayed coast coastal wetland: salinity, crustacea-inhabited; 2. mid-tidal, 2. tide-dominated, macrotidal tidal flat burrow-pocked, terrigenous mud, 3. Tropical humid mangrove-vegetated, metahaline/ hypersaline; 3. high-tidal, smooth, terrigenous mud, hypersaline

CLASSIFICATION

1. Tropical humid, macrotidal, embayed coastal, crustacea-inhabited, marine, rippled terrigenous sand low tidal flat 2. Tropical humid, macrotidal, embayed coastal, mangrove-vegetated, meta/hypersaline, burrow-pocked terrigenous mud mid tidal flat 3. Tropical humid, macrotidal, embayed coastal, hypersaline, smooth, terrigenous mud high tidal flat

Fig. 6.7: Example of proposed classification for coastal wetlands using the coastal zone illustrated in Fig. 6.5, based on a Kimberley coast in Western Australia Tropical humid, macrotidal, embayed coastal, mangrove-vegetated, meta/hypersaline, burrow-pocked terrigenous mud mid tidal flat

Megascale descriptors Microscale descriptors core coastal wetland unit

Tropical humid, mangrove-vegetated, macrotidal, hypersaline, tidal flat embayed coastal burrow-pocked, terrigenous mud mid tidal

Fig. 6.8: Elements of the proposed classification for coastal wetlands using one of the designations in Fig. 6.7, viz., the mid tidal flat