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2.5Nomination Criteria Met by the Site

2.5.1Criteria Under which the Site was Designated


At the time that Kakadu National Park (Stage I and wetland components of Stage III) was extended and Kakadu National Park (Stage II) was first nominated as a Wetland of International Importance, there were 11 criteria against which a wetland site could qualify (Table 2-5). The different criteria which the two Kakadu Ramsar sites were considered meeting are shown in the table below.
Table 2 5 Criteria for identifying Wetlands of International Importance as at listing, as documented in 1989 and 1995 RISs

Basis

Number

Description

Kakadu National Park (Stage I and wetland components of Stage III) - 1995 RIS

Kakadu National Park (Stage II) -1989 RIS

Criteria for representative or unique wetlands

1a

it is a particularly good representative example of a natural or near-natural wetland, characteristic of the appropriate biogeographical region.

Met

Met

1b*

it is a particularly good representative example of a natural or near-natural wetland, common to more than one biogeographical region.

Met




1c*

it is a particularly good representative example of a wetland, which plays a substantial hydrological, biological or ecological role in the natural functioning of a major river basin or coastal system, especially where it is located in a trans-border position.

Met

Met

1d*

it is an example of a specific type of wetland, rare or unusual in the appropriate biogeographical region.







General Criteria based on plants and animals

2a

it supports an appreciable assemblage of rare, vulnerable or endangered species or subspecies of plant or animal, or an appreciable number of individuals of any one or more of these species.

Met

Met

2b

it is of special value for maintaining the genetic and ecological diversity of a region because of the quality and peculiarities of its flora and fauna.

Met

Met

2c

it is of special value as the habitat of plants or animals at a critical stage of their biological cycle.

Met

Met

2d

it is of special value for one or more endemic plant or animal species or communities.




Met

Specific criteria based on waterbirds

3a

it regularly supports 20 000 waterbirds

Met

Met

3b*

it regularly supports substantial numbers of individuals from particular groups of waterbirds, indicative of wetland values, productivity or diversity.

Met

Met

3c

where data on populations are available, it regularly supports one percent of the individuals in a population of one species or subspecies of waterbirds.

Met




*Criteria not available in 1980 when Stage I was first nominated as a Wetland of International Importance, note that Criterion 1 in 1980 was considered a grouping of 1(a) and 1 (d).

The 1998 RIS assessed the site against the 13 criteria adopted at the 6th Conference of Contracting Parties in Brisbane in 1996, Table 2-6 summarises the criteria met by the two historic (pre-merger) Ramsar sites and those that are met by the current ECD.


Table 2 6 Summary of nomination criteria met by the two historic Kakadu National Park Ramsar sites as outlined in the 1998 RIS, and the current Kakadu National Park ECD

Criterion


Historic Kakadu National Park (Stage I and wetland components of Stage III)

Historic Kakadu National Park (Stage II)

Kakadu National Park




1998 RIS

1998 RIS

Current ECD

Group A. Sites containing representative, rare or unique wetland types

1

A wetland should be considered internationally important if it contains a representative, rare, or unique example of a natural or near-natural wetland type found within the appropriate biogeographic region.

Met as 1a - The floodplains are outstanding examples of their types in the monsoon tropics.

Met as 1b - No justification provided.

Met as 1c - The two river systems of the wetlands are outstanding examples of the series of large rivers of the Torresian monsoonal biogeographic region draining into the Arafura Sea. Together with the West Alligator and Wildman rivers in the adjoining wetland of Kakadu National Park Stage II they are the only such river systems under statutory conservation management.


Met as 1a - No justification provided.

Met as 1c - The three river systems of the wetlands are outstanding examples of the series of large rivers of the Torresian monsoonal biogeographic region draining into the Arafura Sea. Together with the East Alligator and upper South Alligator rivers in the adjoining Stage 1 wetland they are the only such river systems under statutory conservation management.

Met

Group B. Sites of international importance for conserving biological diversity

2

A wetland should be considered internationally important if it supports vulnerable, endangered, or critically endangered species or threatened ecological communities.

Met as 2a - The wetland is noted for or important to the conservation of the magpie goose, whistling tree duck, Burdekin duck, yellow chat, eastern grass owl, collared kingfisher, false water rat, goldenbacked tree rat, pig-nosed turtle, Mariana's hardyhead, exquisite rainbow fish, Midgley's grunter and the frog Megistolotes lignarius.


Not met

Met

3

A wetland should be considered internationally important if it supports populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region.

Met as 2b - No justification provided.

Met as 3b - Between August and October up to one million waterbirds accumulate on the floodplains, notably those of Nourlangie Creek. More than 60 species of waterfowl occur in the wetlands including large concentrations of magpie geese and wandering whistling duck.


Met as 2b - No justification provided.

Met as 3b - Between August and October up to one million waterbirds accumulate on the floodplains, notably those of Magela Creek. More than 60 species of waterfowl occur in the wetlands including large concentrations of magpie geese and wandering whistling duck.

Met

4

A wetland should be considered internationally important if it supports plant and/or animal species at a critical stage in their life cycles, or provides refuge during adverse conditions.

Met as 2c - Magpie geese, wandering whistling duck and many other species breed in the wetlands but most species are dry season migrants. Thirty-five species of wader have been recorded, including many winter migrants to the sub-Arctic, whose first Australian landfall is the Kakadu National Park area. Fifty-nine fish species (excluding obligate marine species) are known from the wetland including eight with narrowly restricted ranges. Breeding populations of both freshwater and estuarine crocodiles occur.


Met as 2c - Magpie geese, wandering whistling duck and many other species breed in the wetlands but most species are dry season migrants. Thirty-five species of wader have been recorded, including many winter migrants to the sub-Arctic, whose first Australian landfall is the Kakadu National Park area. Fifty-nine fish species (excluding obligate marine species) are known from the wetland including 8 with narrowly restricted ranges. Breeding populations of both freshwater and estuarine crocodiles occur.

Met

5

A wetland should be considered internationally important if it regularly supports 20 000 or more waterbirds.


Met as 3a - Between August and October up to one million waterbirds accumulate on the floodplains, notably those of Nourlangie Creek.


Met as 3a - Between August and October up to one million waterbirds accumulate on the floodplains, notably those of Magela Creek.

Met

6

A wetland should be considered internationally important if it regularly supports one percent of the individuals in a population of one species or subspecies of waterbird.

Met as 3c - No justification provided.


Met as 3c - No justification provided.

Met

7

A wetland should be considered internationally important if it supports a significant proportion of indigenous fish subspecies, species or families, life-history stages, species interactions and/or populations that are representative of wetland benefits and/or values and thereby contributes to global biological diversity.







Met

8

A wetland should be considered internationally important if it is an important source of food for fishes, spawning ground, nursery and/or migration path on which fish stocks, either within the wetland or elsewhere, depend.







Met

9

A wetland should be considered internationally important if it regularly supports one percent of the individuals in a population of one species or subspecies of wetland-dependent non-avian animal species.







Met

Italicised text is justification as stated in the 1998 RIS; blue shading indicates criteria did not exist at the time of the 1998 RIS

2.5.2Assessment Based on Current Information and Ramsar Criteria


There have been a number of developments in the past decade that influence the application of the Ramsar criteria to wetland sites this includes:

  • Refinements and revisions of the Ramsar criteria since 1996. An additional criterion was added at the 9th Ramsar Conference in Uganda in 2005.

  • Revision of population estimates for waterbirds (Wetlands International 2006; Bamford et al. 2008), which influences the application of criterion six.

  • A decision with respect to the appropriate bioregionalisation for aquatic systems in Australia, which for inland systems are now based on drainage divisions and for marine systems the interim marine classification and regionalisation for Australia (IMCRA). This affects the application of criteria one and three.

  • Updating of threatened species listings, which affects criterion two.

  • Additional data have been collected for the site, which could potentially influence the application of all criteria.

Therefore an assessment of the Kakadu National Park Ramsar site against the current nine Ramsar criteria has been undertaken. The Nomination Criteria have been reconsidered in this ECD, with specific reference to more up-to-date requirements outlined in “Handbook 14 Designating Ramsar Sites” (Ramsar Convention Secretariat 2007) and the National Framework (DEWHA 2008).


2.5.3Criterion 1


A wetland should be considered internationally important if it contains a representative, rare, or unique example of a natural or near-natural wetland type found within the appropriate biogeographic region.

Criterion 1 (met at time of listing and continues to be met based on current assessment)

Criterion 1 considers habitat types and their representativeness within a given biogeographic region (bioregion). As outlined in Section 1.4.5, the site occurs in the Timor Sea Drainage Division and the Northern IMCRA Provincial Bioregion. The Timor Sea Drainage Division contains several major river systems which include (proceeding northward then eastward) the Fitzroy, Isdell, Prince Regent, Mitchell, Drysdale, King George, Ord, Victoria, Adelaide, Mary, West, South and East Alligator, Mann and Goyder Rivers. Of these, the Ord, Victoria Daly and Fitzroy Rivers are the largest by area and flow volumes (CSIRO 2009).

As discussed in Section 2.4, the wetland types occurring within the site are representative of landscape and wetland types found in the Northern IMCRA Provincial Bioregion and the Timor Sea Drainage Division. The 1998 RISs note that:


  • The floodplains are outstanding examples of their types in the monsoon tropics (Stage I/III and II).

  • The three river systems are outstanding examples of the series of large rivers of region (Stage I/III and II), and are the only rivers under statutory conservation management within the region.

Of particular noteworthiness, the Kakadu National Park Ramsar site incorporates all major ‘Top End’ habitat types within a single drainage basin – the South Alligator River (Director of National Parks 2007). There are no particularly unique or rare wetland types within the site, and the range of landscape and wetland habitat types are found in other catchments within the bioregion (for example, Mary River, Adelaide River).

Unlike more developed areas of Australia, most catchments, rivers and estuaries in the Timor Sea drainage division, including those within the Kakadu National Park Ramsar site, are considered in a natural or near-natural condition (National Land and Water Resources Audit 2002; see Figure 2-17). Unlike other catchments within the bioregion, the Ramsar site and most of the catchment area of constituent wetlands are situated within a National Park, and are therefore subject to limited direct development pressure. Floodplain wetlands have also largely recovered from past disturbance by water buffalo (see Section 5.2), although areas of moderate degradation occur in places as a result of impacts of weeds and feral animals (Figure 2-17). Mining has also resulted in disturbance to the landscape although the extent of disturbance is relatively small (see Section 5.5).

The fundamental processes that control wetland functioning, notably fluvial hydrology, tidal hydraulics and water quality processes remain in natural condition (see Section 3.5). Fire regimes, which are a key control of flora and fauna communities and populations in non-tidal areas, are actively managed within the Kakadu National Park (see Section 3.5.2). Furthermore, there is a major management program for weeds and feral animals within Kakadu National Park, but this is unmatched elsewhere in the bioregion.





Figure 2 21 (B) Catchment condition (C) estuary condition and (D) river condition at a bioregional scale. Red rectangle indicates location of the Kakadu Ramsar site. (source: NLWRA 2002)

For these reasons, the site is considered to be excellent representative examples of wetlands in the bioregion and which are in natural or near-natural condition.

An outline of the justification for how the site meets this Criterion is provided in Table 2 -7 below. Noteworthy features that provide justification for this Criterion include the vast areal coverage of relatively intact floodplain habitats and Field Island contains representation examples of all of the coastal wetland types known to occur within the Ramsar site, with the exception of coastal freshwater lagoons. This represents a remarkably high level of habitat diversity within a relatively small area.
Table 2 7 Justification for criterion 1

Ramsar Handbook Element

Justification

Representative, rare, unique wetland type in natural/near-natural condition

  • All wetland types are in natural/near-natural condition and are representative of wetland types found in the Northern IMCRA Provincial Bioregion and within the Timor Sea Drainage Division.

  • No unique or rare wetland types known to occur within the site.

Substantial role in natural functioning of a major river basin or coastal system

  • The site contains almost the complete catchment of the South Alligator and Wildman drainage basins, which in the case of South Alligator, represents one of the largest river systems in the drainage division.

Hydrological importance:

  • The vast floodplain systems provide dry season water retention for floodplain wetlands.

  • The vast floodplain systems represent a major natural floodplain system.



2.5.4Criterion 2


A wetland should be considered internationally important if it supports vulnerable, endangered, or critically endangered species or threatened ecological communities.

Criterion 2 (met at time of listing and continues to be met based on current assessment)

The ECD Framework (DEWHA 2008) indicates that ‘wetland’ flora and fauna species should be considered in the context of this Criterion. This has been interpreted here as ‘wetland-dependent’ species, and therefore does not include terrestrial species that are not reliant on aquatic/wetland habitats (see Appendix C for complete species lists as well as a list of wetland-dependent vertebrate fauna). It is also possible that threatened aquatic invertebrate species also occur with the site (for example, species of dragonfly, see Clausnitzer et al. 2009), however these are either not listed as nationally or internationally threatened, or there are no published records of these species within the site.

No internationally or nationally threatened wetland-dependent flora species are known to occur within the Kakadu National Park Ramsar site. There are nine internationally or nationally threatened wetland-dependent fauna species known to occur within the site as outlined in Table 2 -8. Further information on these species has been provided in Section 3.7.1 in the context of the threatened species critical service.

Note that the Australian painted snipe Rostratula australis, listed as vulnerable under the EPBC Act, is not included above as there are no verified records within the site, though it is acknowledged that areas of potentially suitable habitat occur within the site and this cryptic species may occur within either site. Franklin (2008) lists 34 records of the Australian painted snipe within the northern tropical rivers catchments (a study area which includes Kakadu National Park), and found that records were concentrated in drier parts of the northern catchments.

The water mouse Xeromys myoides is listed as vulnerable under the EPBC Act and by the IUCN. There is a single record from Kakadu National Park in 1903, though no further evidence of the water mouse occurrence has been confirmed, despite recent targeted surveys in potentially suitable habitat (for example, intertidal mangrove wetlands and adjacent salt marsh and sedgeland) (S. Ward pers. comm. 2009). As a result, this species has not been included in the context of meeting the Criterion.
Table 2 8 Threatened wetland-dependent species

Species

Common name

Status

Habitats

Site Usage

Semi-aquatic terrestrial Fauna

Epthianura crocea tunneyi

yellow chat (Alligator Rivers)

EPBC - E

Saltmarsh/palustrine wetland.

Major population present on-site (e.g. Woinarski and Armstrong 2006).

Carettochelys insculpta

pig-nosed turtle

IUCN - V

Floodplain billabongs.

Major population present on-site (e.g. Georges and Kennett 1989).

Marine Megafauna

Glyphis garricki sp. nov.
(formerly Glyphis sp. C)

northern river shark

EPBC – E

IUCN – E



Relatively shallow, upper freshwater to brackish (0-26 ppt) river reaches (TSSC 2001a).

Recorded in West, East and South Alligator Rivers (Larson 2000).

Glyphis glyphis
(formerly Glyphis sp. A)

speartooth shark

EPBC – CE

IUCN - E


Freshwater and brackish areas of rivers (0.8 to 28 ppt) (Pillans et al. 2005; Pogonoski and Pollard 2003).

Populations known to occur in East and South Alligator Rivers (Compagno et al. 2008).

Natator depressus

flatback turtle

EPBC –V

IUCN – DD



Nesting on open coastline (sand beaches).

Feeds in turbid coastal waters, mostly on benthic fauna.



Field Island is an important nesting area (Schäuble et al. 2006), forming part of one of six major nesting sites in Australia.

Pristis clavata

dwarf sawfish

EPBC –V

Turbid rivers and coasts

Record from South Alligator River (Larson et al. 2006a).

Pristis microdon

freshwater sawfish

EPBC –V

IUCN – CE



Typically found in turbid channels of large rivers over soft mud bottoms (Allen 1991) > 1 m deep.

Recorded in Kakadu National Park (Larson et al. 2006) however population status unknown.

Chelonia mydas

green turtle

EPBC –V

IUCN – E



Feeds on seagrass and mangroves.

Recorded at the site (Winderlich 1998 cited in Schäuble et al. 2006) but not thought to represent a key area.

Dugong dugon

dugong

IUCN - V

Feeds on seagrass (particularly Halophila and Halodule).

Extensive seagrass beds at Field Island are dugong feeding areas (Roelofs et al. 2005).

Blue shading – while the species occurs on the site, it is not thought that the site provides a particularly important habitat for this species.

Status under the EPBC Act and IUCN Red List where CE = critically endangered, E = endangered, V = vulnerable, DD = data deficient.



2.5.5Criterion 3


A wetland should be considered internationally important if it supports populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region.

The site meet Criterion 3 for most elements outlined in Section 70 of the Ramsar Handbook for Wise Use of Wetlands 14 (Ramsar Convention Secretariat 2007), namely:



Section 70 (i) High biodiversity

A range of endemic species occur at the site (see below), automatically qualifying the site as supporting high biodiversity. In addition, the site also supports a diverse assemblage of flora and fauna species, including:



  • Nearly 1600 plant species (Director of National Parks 2007).

  • Sixty-one mammal species, including four species regarded as wetland-dependent (Appendix C).

  • One hundred and five reptile species, including 20 species regarded as wetland-dependent (Appendix C).

  • Twenty-six frog species (all wetland-dependent species) (Appendix C).

  • Two hundred and sixty-seven bird species, comprising 91 waterbird species (including 28 migratory and nine resident shorebird species, and 10 gull and tern species) and 11 bird species (other than waterbirds) which regarded as wetland-dependent (Appendix C).

  • Fifty-nine fish species (Bishop et al. 2001; see Appendix C), which represents over half of the total freshwater fish fauna of the Timor Sea bioregion (Allen et al. 2002) (refer Section 2.5.9).

Species lists for terrestrial vertebrate fauna recorded within the site (as well as wetland-dependent vertebrate fauna) are provided in Appendix C.

Section 70 (ii). Centres of endemism or contains significant numbers of endemic species

Wetland flora within the Ramsar site is largely comprised of wide-ranging, non-endemic species, with only four species present that are restricted to the drainage division - Bambusa arnhemica, Hygrochloa aquatica, Nymphoides spongiosa and N. subacuta (Cowie et al. 2000).

The ancient stone country contains significant endemic aquatic invertebrate components, including:


  • Endemic family of shrimps (Kakaducarididae), containing two mono-specific genera (Leptopalaemon and Kakaducaris) (Bruce 1993, Page et al. 2008).

  • Endemic genus of isopod (Eophreatoicus) that has exceptional species diversity (approximately 30 species, Wilson et al. 2009).

  • A high proportion of mayfly species from the family Leptophlebiidae is endemic to the bioregion. Specifically, seven of the nine species found in Kakadu National Park are endemic to the Timor Sea Drainage Division (Finlayson et al. 2006), with one of these species thought to be restricted to a single stream within the Ramsar site (Dean and Suter 2004).

Kakadu National Park contains a significant portion of the total geographic range of four freshwater fish species that are restricted to the drainage division (Allen et al. 2002). These species are exquisite rainbowfish Melanotaenia exquisita, Magela hardyhead Craterocephalus marianae (also known as Mariana’s hardyhead), sharp-nosed grunter Syncomistes butleri and Midgley's grunter Pingalla midgleyi.

Section 70 (iii) Contain the range of biological diversity (including habitat types) occurring within a region.

In terms of species, the site contains the range of tree and shrub mangrove species for the bioregion (38 species).

In terms of habitat types, the current study identifies that almost all Ramsar Wetland types known to occur within the bioregion are represented within the site. Specifically, nine of the 12 Ramsar marine/coastal wetland types occur within the Kakadu National Park Ramsar site (refer Section 2.4.1), noting however that all marine/coastal wetland types are represented within the Timor Sea Drainage Division. The current study also identifies that eight of the 20 inland/freshwater Ramsar wetland habitat types are supported in the site (refer Section 2.4.2), noting that at least four of the inland wetland types absent from the site do not occur within the bioregion (Types U, Va, Vt and Zg).
Table 2 9 Ramsar nomination criterion 3

Wetland feature

Description

High biodiversity

  • A wide range of plant and animal species.

Centres for endemism

  • Four flora species endemic to the drainage division.

  • Shrimp family endemic to drainage division.

  • Isopod genus endemic to drainage division.

  • Seven mayfly species endemic to drainage division.

  • Four fish species endemic to the drainage division.

Contain range of diversity of the bioregion

  • The site contains the range of tree and shrub mangrove diversity for the bioregion.

Contain range of habitat types known from bioregion

  • All but three coastal/marine Ramsar wetland types.

  • Eight of the twenty inland Ramsar wetland types.

Significant proportion of species adapted to special environmental conditions

Most floodplain-associated species have life-cycle characteristics that allow them to persist in seasonally flooded floodplain environments.

Elements of biodiversity that are rare or particularly characteristic of bioregion

N/A



2.5.6Criterion 4


A wetland should be considered internationally important if it supports plant and/or animal species at a critical stage in their life cycles, or provides refuge during adverse conditions.

Based on Ramsar Convention Secretariat (2007), there are two elements that need to be considered for this criterion:



  1. Section 74. Whether the site has high proportions of the population of mobile or migratory species gathered in small areas at particular stages of their life-cycle, and

  2. Section 75. For non-migratory species, whether the site supports habitats for species that are unable to evade unfavourable climatic or other conditions (that is the site contains critical refugia areas).

In the context of Section 74 of Ramsar Convention Secretariat (2007), the following are relevant in addressing this Criterion:

  • Breeding habitat for significant waterbird aggregations. The most significant breeding colonies are located within mangal communities of the major rivers, and floodplain-associated freshwater marshes. Examples include:

  • Colony near mouth of South Alligator River – Multi-species colony with an estimated colony size of up to 5000 waterbirds (Chatto 2000).

  • Colony within mangroves adjacent to and east of South Alligator River, approximately 15 kilometres from the South Alligator River mouth. This is a large multi-species colony (exceeding 13 000 birds per annum in some years) that is dominated by egrets. Eight waterbird species have been confirmed to breed here (Chatto 2000).

  • Colony within mangroves along the southern banks of the East Alligator River and extending up a tributary approximately 15 kilometres in from river mouth. Ten waterbird species have been confirmed to breed here, with the highest estimated annual usage exceeding 11 500 birds (Chatto 2000).

  • Significant breeding aggregations of magpie geese Anseranas semipalmata throughout the floodplains of the site (up to 27 percent of the Northern Territory breeding population), with the South Alligator floodplains regarded as the third most important area of nesting habitat after the Mary-Adelaide and Daly River floodplains (Bayliss and Yeomans 1990).

  • Feeding and roosting habitat for:

  • Thirty-nine shorebird species (including 29 non-breeding migratory species), which collectively occur in significant numbers. The site is identified as being internationally important for migratory shorebirds in the East Asian-Australasian Flyway (Bamford et al. 2008).

  • Fifty-three waterbird species (other than shorebirds), which collectively occur in significant numbers (see data for Criterion 5).

  • In the context of Section 75 in Ramsar Convention Secretariat (2007), the following are relevant in addressing this Criterion:

  • Dry season refuge for large concentrations of waterbirds as a result of the persistence of freshwaters on the Magela and Nourlangie floodplains and several back swamps of the South Alligator River (for example, Boggy Plain) (Morton et al. 1990b). During the late dry season, waterbird abundance is likely to exceed a million birds (Morton et. al. 1991). Notable records include a maximum monthly dry season mean abundance (1981 to 1984) of 545 000 birds from nine waterbird species (Morton et al. 1993b) and approximately 600 000 birds from five duck species (Morton et al. 1990b). Such large aggregations appear to be unique in Australia (Morton et al. 1990b).

  • Feeding, refuge and breeding habitats for terrestrial vertebrate fauna species (other than waterbirds) regarded as wetland-dependent. These include:

  • Three mammal species: northern myotis Myotis moluccarum, mangrove pipistrelle Pipistrellus westralis, and water-rat Hydromys chrysogaster.

  • A wide variety of reptiles are known to depend on aquatic or semi-aquatic habitats of the site during the dry season (Shine 1986a,b, Sadlier 1990, Friend and Cellier 1990, Braithwaite et al. 1991, Woinarski and Gambold 1992, Finlayson et al. 2006). This includes freshwater crocodile Crocodylus johnstoni, saltwater crocodile Crocodylus porosus, pig-nosed turtle Carrettochelys insculpta, Chelodina burrungandjii, northern long-necked turtle Chelodina rugosa, northern snapping turtle Elseya dentata, Elseya jukesi, saw-shelled turtle Elseya latisternum, northern red-faced turtle Emydura victoriae, mangrove monitor Varanus indicus, Merten’s water monitor Varanus mertensi, Mitchell’s water monitor Varanus mitchellii, water python Liasis fuscus, Arafura file snake Acrochordus arafurae, little file snake Acrochordus granulatus, bockadam Ceberus rynchops, Macleay’s water snake Enhydris polyepis, white-bellied mangrove snake Fordonia leucobalia, Richardson's mangrove snake Myron richardsonii and keelback Tropidonophis mairii.

  • Twenty-six frog species have been recorded on the site (for example, Tyler et al. 1983, Tyler and Cappo 1983, Tyler and Crook 1987, Woinarski and Gambold 1992, Finlayson et al. 2006, see Appendix C).

  • Twelve bird species (other than waterbirds): osprey Pandion haliaetus, white-bellied sea-eagle Haliaeetus leucogaster, brahminy kite Haliastur indus, azure kingfisher Alcedo azurea, little kingfisher Alcedo pusilla, collared kingfisher Todiramphus chloris, yellow chat Epthianura crocea tunneyi, mangrove robin Eopsaltria pulverulenta, white-breasted whistler Pachycephala lanioides, mangrove golden whistler Pachycephala melanura, shining flycatcher Myiagra alecto, and mangrove grey fantail Rhipidura phasiana (see Appendix C).

    The permanent billabongs and river channel environments provide dry season refugia for these semi-aquatic wetland-dependent species, as well as purely aquatic species such as fish, and many aquatic invertebrates and macrophyte species. It should be noted however that these same refugia functions would also take place in other permanent waterbodies in wetlands throughout the bioregion. It is uncertain how critical the Ramsar site is in terms of maintaining viable populations of most of the non-migratory/non-mobile species. The possible exceptions to this are threatened and/or endemic species, such as:

  • Endemic invertebrate species found in the stone country (see section 2.5.3). Note however that the specific watering requirements of these species are unknown.

  • The regionally endemic exquisite rainbowfish Melanotaenia exquisita, which is restricted to perennial pools at Jim Jim Creek within the Park (see section 2.6.2).

  • The perennial river systems of the site which support two threatened shark species, two threatened sawfish species and pig-nosed turtle (see Section 2.5.2).

2.5.7Criterion 5


A wetland should be considered internationally important if it regularly supports 20 000 or more waterbirds.

The findings of various studies indicate that the site regularly supports in excess of 20 000 or more waterbirds on an annual basis (Bayliss and Yeomans 1990, Bamford 1990, Morton et al. 1991, Chatto 2000, Chatto 2003a, Chatto 2006, see Appendix C). Peaks in abundance occur immediately prior to and after the wettest months of the year (January–March). During these peak periods, the waterbird population within floodplain areas of the site has been estimated to contain almost one million birds, with densities of up to 100 birds per hectare recorded during the late dry season (Morton et al. 1991). The total waterbird population for the Alligator Rivers Region during the late dry season is likely to be in excess of 2.5 million birds (Morton et al. 1993b). Notable records of waterbird abundance are outlined below:



  • The highest estimated annual usage of the five largest breeding colonies collectively amount to greater than 40 500 birds (Chatto 2000).

  • In excess of 172 000 waterbirds were counted within the upstream South Alligator River floodplains during October 2001 (Chatto 2006). Approximately 23 000 birds were recorded within the downstream floodplains and approximately 49 000 birds were recorded within the upstream floodplains of the East Alligator River in October 2001 (Chatto 2006).

  • The highest monthly mean for the dry season is 545 000 birds from nine waterbird species and approximately 600 000 birds from five duck species across five floodplains in the Alligator Rivers Region: Magela, Nourlangie, East Alligator River floodplains (upstream and downstream), and Boggy Plain (Morton et al. 1990a and 1993b).

  • Bamford (1990) recorded nearly 69 000 waterbirds during ground counts on a limited number of floodplain billabongs in October to November 1987.

  • Chatto (2003a) recorded large aggregations of shorebirds from Finke Bay (9000 birds in 1993) and in coastal areas between the South Alligator River and Minimini Creek (12 500 birds in 1992).

  • For a single species alone, namely magpie goose Anseranas semipalmata, population estimates exceeded 300 000 birds in each of the five years surveyed (1983-1986) with the highest estimate during the 1984 dry season (2 539 802 ± 1 372 568) and lowest estimate during the 1986 wet season (517 998 ± 210 353) (Bayliss and Yeomans 1990). Morton et al. (1990a) estimated that the Alligator Rivers Region (that is, Magela, Nourlangie, East Alligator, Cooper and South Alligator (Boggy Plain) floodplains) supports an average of about 1.6 million geese in the dry season, though considerably less during the wet season (November to March).

2.5.8Criterion 6


A wetland should be considered internationally important if it regularly supports one percent of the individuals in a population of one species or subspecies of waterbird.

The following waterbird species have been recorded within Kakadu National Park in numbers which exceed one percent of the estimated population size (Wetlands International 2006):



  • Magpie goose Anseranas semipalmata - The one percent population threshold for this species is 20 000 birds (Wetlands International 2006). Significant counts include:

  • Annual population counts in excess of 300 000 birds and estimates of greater than 1.6 million geese in the dry season (see Section 2.5.5).

  • Highest estimated number of nests in the years 1984 to 1986 was 45 200 ± 9403 (1985), with the lowest being 24 446 + 5373 (1986) (Bayliss and Yeomans 1990).

  • Bamford (1990) recorded 32 154 magpie geese during surveys in October to November 1987.

  • Wandering whistling-duck Dendrocygna arcuata - The one percent population threshold for this species is 10 000 birds (Wetlands International 2006). Peak abundance (highest monthly mean for period 1981-1984) for the flood plains of the Alligator Rivers Region was estimated to be 400 000 birds (Morton et al.1990b).

  • Plumed whistling-duck Dendrocygna eytoni - The one percent population threshold for this species is 10 000 birds (Wetlands International 2006). Peak abundance (highest monthly mean for period 1981-1984) for the flood plains of the Alligator Rivers Region was estimated to be 70 000 birds (Morton et al.1990b).

  • Radjah shelduck Tadorna radjah – A one percent population threshold has not been calculated for this species (Wetlands International 2006), though the following comments provide a guide – Garnett and Crowley (2000) estimate an Australian population of 100 000 breeding adults (150 000 individuals), though population may be smaller (Wetlands International 2006). In assuming the upper estimate, counts recorded for the site would exceed any conservative estimate of a one percent population threshold. Morton et al. (1990b) estimated peak abundance (highest monthly mean for period 1981-1984) for the flood plains of the Alligator Rivers Region to be 30 000 birds.

  • Pacific black duck Anas superciliosa - The one percent population threshold for this species is 10 000 birds (Wetlands International 2006). Peak abundance (highest monthly mean for period 1981-1984) for the flood plains of the Alligator Rivers Region was estimated to be 50 000 birds (Morton et al.1990b).

  • Grey teal Anas gracilis - The one percent population threshold for this species is 20 000 birds (Wetlands International 2006). Peak abundance (highest monthly mean for period 1981-1984) for the flood plains of the Alligator Rivers Region was estimated to be 50 000 birds (Morton et al.1990b).

  • Brolga Grus rubicunda - The one percent population threshold for this species is 1000 birds (Wetlands International 2006). Peak abundance (highest monthly mean for period 1981-1984) for the flood plains of the Alligator Rivers Region was estimated to be 24 000 birds (Morton et al.1993a).

  • Black-necked stork Ephippiorhynchus asiaticus - The one percent population threshold for this species is 300 birds (Wetlands International 2006). Aerial counts (which in comparison to ground surveys are known to under-estimate numbers) undertaken monthly between 1981 and 1984 demonstrated that estimated average numbers on the floodplains of Alligator Rivers exceeded the one percent threshold for five of the 12 counts (Morton et al.1993a). From both ground and aerial counts, a measure of the maximum regional population was estimated to be about 1800 birds (Morton et al.1993a).

The following migratory shorebird species have been recorded within Kakadu National Park in numbers which exceed one percent of the estimated population size in the East Asian – Australasian Flyway (Bamford et al. 2008):

  • Marsh sandpiper Tringa stagnatilis – Bamford et al. (2008) estimates that the one percent population threshold for the flyway is 1000 birds. Site records include 1600 birds (Chatto 2003a).

  • Little curlew Numenius minutus - The current flyway one percent threshold is 1800 (Bamford et al. 2008). Site records include 180 000 birds (Morton et al. 1990). Morton et al. (1991) reported approximately 300 000 little curlew passing through the wetlands in Kakadu National Park during October in the early 1980’s, and Bamford (1990) reported 50 000 little curlew in Kakadu National Park in the late dry seasons of 1987, 1988 and 1989 (with a single day count from six day roosts of 17 380 birds (11 November 1987) and 10 000 birds from a single roost on Boggy Plains (19 October 1987).

  • Common sandpiper Actitis hypoleucos - The current flyway one percent threshold is 250 (Bamford et al. 2008). Site records include 300 birds (Bamford 1988).

  • Australian pratincole Stiltia isabella - The current flyway one percent threshold is 600 (Bamford et al. 2008). Site records include 30 000 birds (Morton et al. 1991) and 1391 birds (Bamford 1990).

  • Sharp-tailed sandpiper Calidris acuminata - The current flyway one percent threshold is 1600 (Bamford et al. 2008). Site records include 4900 birds (Chatto 2003a) and 3000 birds (Chatto 2003a).

Chatto (2003a) indicates that other species may occur in numbers which exceed the threshold (terek sandpiper Xenus cinereus, broad-billed sandpiper Limicola falcinellus, grey plover Pluvialis squatarola, and lesser sand plover Charadrius mongolus) though suitable data to confirm this view are not currently available.

2.5.9Criterion 7


A wetland should be considered internationally important if it supports a significant proportion of indigenous fish subspecies, species or families, life-history stages, species interactions and/or populations that are representative of wetland benefits and/or values and thereby contributes to global biological diversity.

From a species richness perspective, the freshwater fish fauna of the site is reportedly high on a national scale. To date, 59 freshwater fish species (that is, species that have an obligatory freshwater stage) have been recorded in the site (Bishop et al. 2001; see Appendix C). This represents approximately 20 percent of the total number of fish species found in Australian freshwaters (302 species) and 60 percent of the freshwater fish recorded from the Timor Sea Drainage Division (approximately 100 species) (Allen et al. 2002, CSIRO 2009), and is the highest species richness of any catchment in the bioregion (Burrows 2008). However, Burrows (2008) also notes that this is also by far the most intensively sampled region of northern Australia, both spatially and temporally. Additionally, Burrows (2008) derived species richness values for sampling locations throughout the bioregion based on past surveys, but noted that differences in sampling methods and effort preclude direct comparisons of these data (refer Section 3.3.6).

Allen et al. (2002) notes that the Magela Creek catchment alone is species-rich compared to catchments on other continents, and despite its small size, has as many or more species than the extensive Murray-Darling system in south east Australia.

Five species have been recorded only from the northern part of the Northern Territory (exquisite rainbowfish Melanotaenia exquisita, Magela hardyhead Craterocephalus marianae, sharp-nosed grunter Syncomistes butleri, Midgley's grunter Pingalla midgleyi and a potential new species of Hypseleotris gudgeon), and Kakadu National Park contains a significant portion of the total range of the first four of these species. Ramsar Convention Secretariat (2007) also considers endemism as an important element of biodiversity, and the four fish species listed above are endemic to the drainage division (refer Section 2.5.5).

There are insufficient data to determine the proportion of marine/estuarine fish (or shellfish) species that the Ramsar site support relative to the total fish diversity in the bioregion.

Ramsar Convention Secretariat (2007) also emphasises that the term diversity can encompass a number of life-history stages, species interactions and complexity of fish-environmental interactions. The fish assemblages of the site is comprised of species with different life-history characteristics, including potadromous (entirely freshwater) species, to diadromous (requiring marine and freshwaters to complete life-cycle) and fully marine species. The site also supports a wide variety of life history stages for many species (i.e. eggs, larvae, recruitment sites, spawning sites).


2.5.10Criterion 8


A wetland should be considered internationally important if it is an important source of food for fishes, spawning ground, nursery and/or migration path on which fish stocks, either within the wetland or elsewhere, depend.

Kakadu National Park provides important habitats, feeding areas, dispersal and migratory pathways, and spawning sites for numerous fish species of direct and indirect fisheries significance. These fish have important fisheries resource values both within and external to the Ramsar site.

No commercial fishing is allowed within the site. However, recreational angling is a key use of the site. The recreational fishery is based almost entirely on one species: barramundi Lates calcarifer, although other non-target species are also captured. From a cultural perspective, barramundi represents a key traditional food species and has other cultural values (for example, totem – see Section 3.7.3; 3.8.4).

While commercial fishing does not occur within the site, many commercially significant species occur within Kakadu National Park that may be harvested elsewhere. Many fish (for example, barramundi, threadfin salmon, mullet species) and crustacean (mud crabs, prawns) species spend their juvenile stages in shallow nearshore waters of the site, particularly around mangroves, saltmarsh and seagrass habitats. Species such as barramundi also inhabit freshwater floodplain and billabongs. These species also spawn in inshore waters, although there is no information on specific spawning habitats within the site (See Section 3.3.6).

Note that Section 3.7.2 (Service 3) provides a more detailed account of fish habitat values of the site.

2.5.11Criterion 9


A wetland should be considered internationally important if it regularly supports one percent of the individuals in a population of one species or subspecies of wetland-dependent non-avian animal species.

Criterion 9 relates to non-avian wetland taxa including, inter alia, mammals, reptiles, amphibians, fish and aquatic macroinvertebrates. In interpreting the application of Criterion 9 to these species, Ramsar Convention Secretariat (2007) indicates that reliable population size limits from published sources must be included in the justification for the application of this Criterion.



The following species meet this Criterion:

  • Northern river shark Glyphis garricki sp. nov This species occurs in scattered localities in coastal New Guinea and Australia, with specific Australian locations known to be King Sound and Doctors Creek in Western Australia, and the Adelaide, West, East and South Alligator Rivers in the Northern Territory (Compagno et al. 2008). It is inferred that the total population size of this species is estimated to be 250 mature individuals (see Ward and Larson 2006a). Based on this, the one percent population threshold is three individuals, and therefore this species is considered to exceed the one percent population threshold as it is known from three localities within the Ramsar site.

  • Speartooth shark Glyphis glyphis – This species occurs in scattered localities in northern Australia, with specific locations known to be the Bizant and Wenlock Rivers in Queensland and the Adelaide, East Alligator and South Alligator Rivers in the Northern Territory, as well as near Port Romilly in New Guinea (Compagno et al. 2008). It is inferred that the total population size of this species is estimated to be 250 mature individuals (see Ward and Larson 2006b). Therefore, the one percent population threshold is exceeded within the Ramsar site.

  • Pig-nosed turtle Carettochelys insculpta – This species occurs in New Guinea and northern Australia. Within Australia, substantial breeding populations of pig-nosed turtles are known to occur in four major river drainages in the Northern Territory, namely, the East Alligator, South Alligator, Daly and Victoria Rivers (TSSC 2005), with reliable anecdotal reports also including the Victoria, Fitsmaurice and Goomadeer systems (Doody et al. 2000). As the Australian pig-nosed turtle population is completely isolated from the New Guinean populations (Cogger and Heathcote 1981), the one percent population threshold is calculated based on only the Australian numbers of individuals. Population surveys estimate that the Australian population is approximately 3000 individuals (R. Sims pers. comm. to TSSC 2005), and the one percent threshold is therefore 30 individuals. Georges and Kennett (1989) found pig-nosed turtles to be widespread between the tidal reaches and the head-waters of the South Alligator River, and that high densities may be present in the upper reaches during the dry season (33.8 ± 11.3 turtles per hectare in small discrete ponds on the main channel). Based on this information, the one percent population threshold is exceeded within the Ramsar site.

  • Saltwater crocodile Crocodylus porosus – Although saltwater crocodiles have historically had a wide distribution throughout southeast Asia and Australasia, the species is currently thought to be extinct throughout most of Asia. Isolated, relatively small populations are known to remain in Myanmar (Burma), eastern India, Indonesia, Malaysia, Philippines and the Solomon Islands. The vast majority of the global population of saltwater crocodiles occurs in northern Australia, and they are also common in New Guinea. In Australia, the saltwater crocodile population has been thriving since the species was protected from hunting, particularly in the Northern Territory, which has the largest population and densities in Australia (Fukuda et al. 2007), and population size is estimated as 60 000 individuals (NTG not dated), but may actually be far greater than this number (Simon Ward pers. commo. 2010). Within the Northern Territory, Kakadu National Park (Alligators Rivers Region) contains the largest protected area of suitable habitat (approximately 19 120 km2) (Leach et al. 2009) and it is estimated that the site contains approximately 15 000 saltwater crocodiles (S. Ward pers. comm. 2009), therefore exceeding the one percent population threshold.

It is likely that the freshwater crocodile Crocodylus johnstoni also meets this Criterion; however, sufficient data are not available at the site scale to determine whether the Criterion is met for this species. Freshwater crocodiles are endemic to northern Australia, occurring in Western Australia, Northern Territory and Queensland. Considering their distribution and that the site contains a significant proportion of the suitable habitat within this distribution, it is likely that the site support at least one percent of the population. Should adequate data become available, then this species will be included in this Criterion.

The endemic invertebrate species that appear to be restricted to seeps in the escarpment country are also likely to exceed this threshold. However, as there are no published accurate estimates of population numbers of these species, under Ramsar Handbook 14 guidelines (Ramsar Convention Secretariat 2007) these species cannot contribute to this criterion. It is noted that there has been comparatively less collection effort in other areas outside the site than has occurred in Kakadu National Park. Investigation of survey data for other regionally endemic species as part of the current study has shown such data are largely incomplete and forms an information gap.


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