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2.3Land Use and Tenure

2.3.1Tenure and Land Use within the Site


Tenure

Approximately 50 percent of Kakadu National Park is Aboriginal land under the Aboriginal Land Rights (Northern Territory) Act 1976. Most of the remaining area of land is under claim by Aboriginal people.

Title to Aboriginal land in the Park is held by Aboriginal Land Trusts that have leased their land to the Director of National Parks (established under section 514A of the EPBC Act) for the purpose of being managed as a Commonwealth Reserve. Land in the Park that is not Aboriginal land is vested in the Director.

Stage I of Kakadu National Park was gazetted in April 1979 under the provisions of the National Parks and Wildlife Conservation Act 1975. Traditional owners leased Stage I lands to Director of National Parks and Wildlife Service for a period of 99 years.

Stage II of Kakadu National Park was gazetted in February 1984 under the provisions of the National Parks and Wildlife Conservation Act 1975, and amalgamated with Stage I to create a single Kakadu National Park in December 1985. The Director of National Parks has ownership over 93 percent of the land, whereas the remaining seven percent is vested with Jabiluka Aboriginal Lands Trust. In May 1991 an agreement was formalised to lease Aboriginal lands to the Director for the purposes of a national park.

Stage III of Kakadu National Park was proclaimed 1987, with later proclamations in 1989 and 1991 to increase the size the park, under the provisions of the National Parks and Wildlife Conservation Act 1975.



Land Use

Given that the Ramsar site is located entirely within the boundaries of the gazetted Kakadu National Park, the principal land uses are conservation management, tourism and education and low levels of hunting and gathering by traditional owners living within and around the Park.


2.3.2Tenure and Land Use Adjacent to the Site


Tenure

The Ramsar site is bound by Arnhem Land to the east, most of which is held as the Arnhem Land Aboriginal Reserve. Van Diemen Gulf is situated to the north of the site and is Territory Waters (Crown land). Conservation reserves (declared under Northern Territory legislation), predominantly inactive pastoral leases and the Department of Defence Mount Bundey Training Area are situated to the west of the Ramsar site. Lands to the south of the Ramsar site include Nitmiluk National Park and Jawoyn Indigenous lands.

The Ranger uranium mine and Ranger and Jabiluka mineral leases are excluded from the boundaries of the National Park and the relevant Ramsar boundaries. Mining leases that historically allowed for mining in the southern area of the Park (South Alligator River Catchment) have not been active for some time.

Land Use

Key land use activities in the surrounding areas to the Kakadu National Park include:



  • conservation management, tourism and education (within Northern Territory conservation reserves)

  • uranium mining (undertaken at the Ranger uranium mine near the East Alligator River in the mineral lease area)

  • historical mineral exploration (in the South Alligator River region), which has now been suspended

  • commercial barramundi fishing in marine waters adjacent to the site

  • grazing, and

  • defence force training.

2.4Description of Wetland Types


The Kakadu National Park Ramsar site is composed of a diversity of coastal and inland wetland types. Wetland types present range from intertidal forested wetlands and mudflats, to seasonal freshwater marshes and permanent freshwater pools. For this report, the Ramsar Classification System for Wetland Types (approved by Recommendation 4.7 and amended by Resolutions VI.5 and VII.11 of the Conference of the Contracting Parties) has been adopted.

There is generally a lack of detailed habitat and vegetation community mapping and spatially-referenced ecological data available for the Ramsar site. To date, no mapping according to Ramsar wetland typology has been undertaken for Kakadu National Park. Relevant mapping data at a whole-of-site scale includes:



  • broad-scale (1:1 000 000) vegetation mapping (Wilson et al. 1990)

  • more detailed (1:100 000) mapping for mangroves (provided by Parks Australia) and Melaleuca forest (Brocklehurst and van Kerckhof 1994)

  • mapping of billabongs (digitised for part of the area by BMT WBM 2010 from 1:250 000 topographical mapping, aerial photography and a Digital Elevation Model), and

  • seagrass mapping undertaken by Roelofs et al. (2005).

Numerous other mapping studies provide partial coverage of the site, such as mapping of vegetation communities in the Magela Creek sub-catchment (for example, Finlayson et al. 1989).

These data sources, together with other information describing the habitats and communities of the site (for example, Finlayson et al. 1988, Finlayson and Woodroffe 1996, Cowie et al. 2000, Finlayson 2005), have been considered for this report in order to determine Ramsar wetland types present within the site. Further details and descriptions of these wetland types are provided below and summarised in Table 2 -3 and Table 2-4.

Note that there are some uncertainties regarding the extent and distribution of most wetland types due to the lack of a consistent, systematic mapping of Ramsar wetland habitat types within the site. Where such uncertainties exist, these have been identified in the following sections, including a discussion on discrepancies between wetland types identified as present in the 1998 RISs and those identified by this study. Further, note that this section serves to provide a description of wetland types, while particular values of the wetlands have been highlighted elsewhere in the document where relevant (for example, justification for Nomination Criteria in Section 2.5, descriptions of critical components, processes and services/benefits in Section 3).

Table 2 3 Coastal wetland types and representative examples within Kakadu National Park Ramsar site



Ramsar wetland type

Representative examples

A - Permanent shallow marine waters in most cases less than 6 m deep at low tide; includes sea bays and straits. (i.e. not intertidal)

Absent - Site boundaries extend to the low water mark, therefore no permanent subtidal marine waters are present. Subtidal waters within rivers are classified as estuarine waters (Type F).

B - Marine subtidal aquatic beds; includes kelp beds, sea-grass beds, and tropical marine meadows.

Present - Seagrass beds are mapped around Field Island; small patches occur elsewhere along coastline.

Area is unknown specifically within Ramsar site, but in Van Diemen Gulf 2126 ha A



C - Coral reefs

Absent - Rocky shores and reefs contain corals, but no coral (carbonate) reefs present.

D - Rocky marine shores; includes rocky offshore islands, sea cliffs.

Present - Rocky shoreline along West Alligator Head, Barron Island and Field Island.
Shoreline length approximately 3.2 km B

E - Sand, shingle or pebble shores; includes sand bars, spits and sandy islets; includes dune systems and humid dune slacks.

Present - Pococks and Middle Beach (West Alligator Head), western shoreline of Barron Island, small sandy beach landward of mangroves at mouth of South Alligator River.
Shoreline length approximately 18.5 km B

F - Estuarine waters; permanent water of estuaries and estuarine systems of deltas.

Present - Tidal sections of Wildman, West Alligator, South Alligator Rivers, and the upper estuary of East Alligator River.

G - Intertidal mud, sand or salt flats.

Present - Coastal shoreline between Wildman River mouth and East Alligator River mouth (Point Farewell), Field and Barron Islands.

H - Intertidal marshes; includes salt marshes, salt meadows, saltings, raised salt marshes; includes tidal brackish and freshwater marshes.

Present - Extends along coastline and into the estuarine areas Wildman, East Alligator, West Alligator, South Alligator Rivers, and Point Farewell.

I - Intertidal forested wetlands; includes mangrove swamps, nipah swamps and tidal freshwater swamp forests. (i.e. Mangroves and Melaleuca)

Present - Extends along coastline and into the estuarine areas Wildman, East Alligator, West Alligator, South Alligator Rivers, and Point Farewell.
Area: 8689 ha C

J - Coastal brackish/saline lagoons; brackish to saline lagoons with at least one relatively narrow connection to the sea.

Present - Saline lagoon at northern tip of Field Island; broader distribution within the site unknown.

K - Coastal freshwater lagoons; includes freshwater delta lagoons.

Present - Chenier ridges at Pococks and Middle Beaches reportedly contain freshwater lagoons.

Zk(a) – Karst and other subterranean systems

None mapped or known.

Total marine/coastal wetland types

9

A = Roelofs et al. (2005) – note includes areas outside but contiguous with the site; B = Smartline mapping; C = Mangrove mapping from Parks Australia;
Table 2 4 Inland wetland types and representative examples within Kakadu National Park Ramsar site


Ramsar wetland type

Representative examples

L - Permanent inland deltas.

Present - Yellow Water.

M - Permanent rivers/streams/creeks; includes waterfalls.

Present - e.g. Gubara, Ikoymarrwa, Fern Gully, Koolpin, Radon, Gerowrie, Wildman, West Alligator, South Alligator and South Alligator Rivers.

N - Seasonal/Intermittent/ irregular rivers/ streams/ creeks.

Present - Widespread in upper reaches of all catchments, e.g. Plum Tree Creek.

O - Permanent freshwater lakes (greater than 8 ha); includes large oxbow lakes.

Present - e.g. Leichhardt Billabong, Chirracarwoo Lagoon, Yellow Water, Red Lily, Mamukala, Alligator Billabong, Two Mile Hole, and Palm Swamp

P - Seasonal/intermittent freshwater lakes (less than 8 ha); includes floodplain lakes.

None mapped or known. Note that lakes are considered to be open water features with little vegetation. Intermittent billabongs in the site generally have high vegetation cover, and therefore more conform to type Ts.

Q - Permanent saline/brackish/alkaline lakes.

None mapped or known. Inland waterbodies generally fresh, although brackish lagoons occur in coastal areas (see Table 2-3).

R - Seasonal/intermittent saline/brackish/ alkaline lakes and flats.

None mapped or known. See comment above for type Q.

Sp - Permanent saline/brackish/alkaline marshes/pools.

None mapped or known. See comment above for type Q.

Ss - Seasonal/intermittent saline/brackish/alkaline marshes/pools.

None mapped or known. See comment above for type Q.

Tp -- Permanent freshwater marshes/pools; ponds (less than 8 ha), marshes and swamps on inorganic soils; with emergent vegetation water-logged for at least most of the growing season.

Present - Widespread throughout floodplain of all catchments, e.g. Couramoul Waterhole.


Ts - Seasonal/intermittent freshwater marshes/pools on inorganic soils; includes sloughs, potholes, seasonally flooded meadows, sedge marshes.

Present - Widespread throughout floodplain of all catchments.


U - Non-forested peatlands; includes shrub or open bogs, swamps, fens.

None mapped or known.


Va - Alpine wetlands; includes alpine meadows, temporary waters from snowmelt.

None mapped or known.


Vt - Tundra wetlands; includes tundra pools, temporary waters from snowmelt.

None mapped or known.


W -- Shrub-dominated wetlands; shrub swamps, shrub-dominated freshwater marshes, shrub carr, alder thicket on inorganic soils.

None mapped or known.


Xf - Freshwater, tree-dominated wetlands; includes freshwater swamp forests, seasonally flooded forests, wooded swamps on inorganic soils.

Present - Widespread throughout floodplain of all catchments.

Melaleuca = 74 113 haD


Xp - Forested peatlands; peatswamp forests.

None mapped or known.


Y - Freshwater springs; oases.

Present - e.g. Pheasant Brook, Kanalada Brook, Bellyungardy Spring, Lone Spring.

Zg - Geothermal wetlands

None mapped or known.

Zk(b) – Karst and other subterranean hydrological systems, inland

None mapped or known.


Total Inland Wetland Types

8

D = Brocklehurst and van Kerckhof (1994)

Figure 2 6 Vegetation map for the Ramsar site (source: Tropical Savannas CRC undated)

Note that ‘Kakadu region’ as referenced in the legend is synonymous with the Kakadu National Park boundary.

2.4.1Marine/Coastal Wetland Types Present


Type B: Marine subtidal aquatic beds

This wetland type is represented by intertidal seagrass communities. A seagrass survey that incorporated the Ramsar site mapped approximately 2126 hectares of seagrass beds in the Van Diemen Gulf (Roelofs et al. 2005, refer Figure 2 -7). Almost all of this seagrass occurred around Field Island, with seagrass beds comprised of Halophila ovalis on the north-western shoreline and a mixed bed of H. ovalis and Halodule uninervis on the north eastern shoreline. Elsewhere, small patches of seagrass were recorded around Barron Island, the mouth of South Alligator River and Cape Farewell. Note, however, that only a small proportion of the seagrass occurs within the site, as the Ramsar site boundary extends to the low water mark.

Small patches of seagrass are also thought to be present within the Ramsar site, although seagrass patches were too small to be mapped by Roelofs et al. (2005).

Purple = Halophila ovalis; Green = H. ovalis + Halodule uninervis

Figure 2 7 Distribution of seagrass beds within and adjacent to the Ramsar site (source: Roelofs et al. 2005)




Halophila ovalis



Halodule uninervis

Figure 2 8 Seagrass species occurring within the Ramsar site (source: BMT WBM)
Type D: Rocky marine shores

This wetland type is characterised by exposed rocky marine shores, including rocky offshore islands and sea cliffs. Although not listed in the 1998 RIS for either of the historic (pre-merger) Ramsar sites, Smartline mapping indicates that approximately 3.2 kilometres of rocky shorelines are present in along West Alligator Head, Barron Island and Field Island (refer Figure 2 -9). It should be noted that these Smartline data have not been ground-truthed in detail within the site, although rocky shores are known to occur at all these locations (S. Winderlich, KNP pers. comm. 2010).



Type E: Sand, shingle or pebble shores

This wetland type includes sand bars, spits and sandy islets, as well as dune systems and humid dune slacks. Sandy beaches occur along the eastern and northern shores of Field Island and the western shoreline of Barron Island, as well as at West Alligator Head on the mainland (Pococks and Middle Beach). These sandy beaches are important nesting sites for flatback turtles. A small sandy beach is also present on the landward side of the mangroves at the mouth of the South Alligator River (Figure 2 -9). While sediments along the mainland foreshore contain sand (and mud), these have been colonised by mangroves and are therefore not considered to represent sandy shores.

It should be noted that reliable mapping of sandy shores within the site is not available. The map presented in Figure 2-5, which is based on broad-scale mapping undertaken as part of the national Smartlines mapping project (available from http://www.ozcoasts.org.au/coastal/smartline.jsp#) should be considered as indicative only.

Figure 2 9 Smartline mapping of backshore habitats within the Ramsar site (source: GeoSciences Australia undated)


Type F: Estuarine waters

This wetland type includes permanent waters of estuaries and estuarine systems of deltas. Determining the extent and distribution of estuarine waters is to a large extent dependent on the definition of an estuary. For the purposes of this study, estuarine waters are considered here to include the freshwater/marine interface area within creeks and rivers. It is represented in the estuarine waters are present in the tidal section of the Wildman, East Alligator, West Alligator and South Alligator Rivers.





Figure 2 10 Estuarine waters of the South Alligator River (source: BMT WBM)
Type G: Intertidal mud, sand or salt flats

This wetland type encompasses habitats comprised of deposits of sand and mud that accumulate on intertidal flats. Extensive intertidal mudflats extend along most of the coastline of the Ramsar site. When exposed during low tides, these tidal flats form important feeding areas for large aggregations of shorebirds. Broad, low-lying hypersaline mudflats that are largely unvegetated also adjoin tidal reaches of the rivers and creeks. These tidal flats occur on the landward side of mangrove communities, and often form habitat mosaics with intertidal marshes and mangroves (Figure 2-7).



Type H: Intertidal marshes

This wetland type is represented in the Ramsar site by saltmarsh (samphire) communities that inhabit salt-flats in the coastal zone, and also fringe lower estuarine sections of the main channels (Figure 2-7). Saltmarsh communities are floristically poor, with succulent shrub species present including Tecticornia indica, Suaeda arbusculoides, Tecticornia australasica and Sesuvium portulacastrum, and grasses including Cynodon dactylon and Sporobolus virginicus (Russell-Smith 1995). These species are cosmopolitan in distribution, generally occurring throughout much of coastal Australia.

This wetland type is also represented within the Ramsar site by saline/semi-saline communities that overlie saline muds on the seaward side of floodplains, adjacent to tidal creeks or tidally inundated salt flats, in shallow water that is 20 centimetres deep or less (Cowie et al. 2000). These brackish swamp communities are characterised by grass species such as Leptochloa fusca, Paspalum vaginatum, Sporobolus virginicus and Xerochloa imberbis.



Figure 2 11 Intertidal marshes and saltpans along South Alligator River (source: BMT WBM)
Type I: Intertidal forested wetlands

Within the Ramsar site, intertidal forested wetlands are represented by mangrove communities (Figure 2-8). Extensive mangrove forests extend along the coastal shoreline as well as tidal reaches of rivers and streams, becoming increasingly more fragmented inland and along smaller creeks (refer Figure 2 -13, also see Finlayson and Woodroffe 1996). In particular, mangrove communities fringing the Wildman, West Alligator and South Alligator Rivers are prominent. Approximately 8689 hectares of mangroves are present within the Ramsar site (mapping provided by Parks Australia), noting that these areas may have changed in the time period elapsed since the mapping was done (1989). It should be also noted that mangrove forests on Barron and Field Islands are not mapped by Parks Australia (Figure 2-9), but are known to be well developed at these two locations (Figure 2-2).

Mangrove communities in the Kakadu National Park region are floristically diverse, with thirty-eight mangrove tree and shrub species identified (Wightman 1989). Many of these species are widespread in coastal Australia and throughout Indo-Malaysia (Duke 1992). Species composition of mangrove communities is in zoned bands that run parallel to the shoreline in accordance with species tolerances to environmental conditions. In the coastal region, grey mangrove Avicennia marina is typically on the landward side, a central band is composed of spider mangrove Rhizophora stylosa and a seaward distribution of white mangrove Sonneratia alba (Davie 1985), while Sonneratia lanceolata occurs upstream (Finlayson et al. 1988).

Mangrove communities are highly productive and provide important habitat for fauna species. These include birds, fisheries resources including invertebrates and fish (for example, barramundi) and traditional foods. Furthermore, mangrove communities are notable as they have an important function in coastal stabilisation through protection against coastal erosion, they create a buffer against extreme weather events, and they have a role in sediment trapping and consequently contribute to the quality of coastal waters.




Figure 2 12 Mangroves along the South Alligator River (source: BMT WBM)
Type J: Coastal brackish/saline lagoons

This habitat type includes brackish to saline lagoons with at least one relatively narrow connection to the sea. Although not listed in the 1998 RIS for either of the historic (pre-merger) Ramsar sites, a saline lagoon is present at the northern tip of Field Island. The broader distribution of coastal saline lagoons within the Ramsar site is unknown.



Type K: Coastal freshwater lagoons

This wetland type consists of coastal freshwater lagoons. Although not listed in the 1998 RIS for either of the historic (pre-merger) Ramsar sites, chenier ridges at Pococks and Middle Beaches reportedly contain freshwater lagoons (Buck Salau, Parks Australia pers.comm).





I:\B17399_I_GML Kakadu Ramsar GWF\DRG\ECO_005_091117 Kakadu Vegetation Types.wor

Figure 2 13 Mangroves and Melaleuca forest extent within the Ramsar site (source: Parks Australia unpublished data)


2.4.2Inland Wetland Types Present


Type L: Permanent inland deltas

A permanent inland delta is present at Yellow Water.





Figure 2 14 Yellow Water – an example of a permanent lake and inland delta (source: BMT WBM)
Type M: Permanent rivers/streams/creeks

This wetland type incorporates permanent rivers, streams and creeks, including waterfalls. Representative examples of this wetland type include Coirwong, Barramundi, Jim Jim and Nourlangie Creeks, and Wildman, East Alligator, West Alligator and South Alligator Rivers (Figure 2-11). It is also possible, but not confirmed, that parts of Katherine and Mary Rivers and their tributaries contain this wetland type.

The riparian vegetation communities that line rivers and streams are highly variable depending on the type of river and influences of seasonality (Petty et al. 2008). Common riparian species include weeping paperbark Melaleuca leucadendra, silver-leaved paperbark M. argentea, cajeput M. cajuputi, river pandanus Pandanus aquaticus, river red gum Eucalyptus camaldulensis, freshwater mangrove Barringtonia acutangula, river she-oak Casuarina cunninghamiana, weeping tea-tree Leptospermum longifolium, black wattle Acacia auriculiformis, northern swamp mahogany Lophostemon grandiflorus and L. lactifluus (Brock 1993). A large proportion of riparian flora species are also common to monsoon forests (see Wetland Type Y) (for example, Leichhardt tree Nauclea orientalis, Syzygium armstrongii, white apple S. forte, cluster fig Ficus racemosa, Xanthostemon eucalyptoides), with the margins of these habitats often intergrading (Brock 1993).

Extensive sandbanks may be associated with permanent and seasonal watercourses, and are important for turtle and crocodile nesting.




Figure 2 15 Permanent river wetland type within South Alligator River (source: BMT WBM)
Type N: Seasonal rivers/streams/creeks

This wetland type incorporates seasonal (i.e. ephemeral) rivers, streams and creeks, and is represented within the Ramsar site by seasonal drainings that commence flowing with monsoonal rains marking the start of the wet season. Flow of these seasonal streams and creeks declines and eventually stops in the dry season. Seasonal streams are widespread in the upper reaches of all catchments. Riparian vegetation communities associated with seasonal rivers and streams have been described for Type M above. Additionally, waterfalls occur on the edge of the sandstone plateau, with well-known examples including Jim Jim Falls and Twin Falls (both of which contain permanent water although flows are not perennial).



Type O: Permanent Freshwater Lakes

This wetland type includes permanent freshwater lakes that are larger than eight hectares in area. Although not listed in the 1998 RIS for either historic (pre-merger) site, this wetland type is represented within the Ramsar site by permanent freshwater billabongs that exceed the eight hectares area threshold (as digitised for part of the Ramsar site by BMT WBM 2010, refer Figure 2 -19). With regards to the figure, note that billabong digitisation was only done for a portion of the site, and that only billabongs greater than eight hectares are classified as Type O.

Representative examples of billabongs include Chirracarwoo Lagoon (approximately 101 hectares), Leichhardt Billabong (approximately 17 hectares), Billabong (approximately 32 hectares) and Yellow Water.

Mixed community herblands comprised of submerged, floating and emergent plant species are associated with permanent freshwater billabongs. These communities are often dominated by waterlilies such as white snowflake lily Nymphoides indica and the traditional food species red lily Nelumbo nucifera, with other macrophyte species including Limnophila australis, Triglochin dubium and Caldesia oligococca (Finlayson 2005). Billabongs provide dry season refuges for many of the aquatic fauna species.



Type Tp: Permanent freshwater marshes/pools

This wetland type includes ponds less than eight hectares in area, as well as marshes and swamps on inorganic soils with emergent vegetation that is waterlogged for at least most of the growing season. Within the Ramsar site, it is represented by permanent freshwater billabongs that are smaller than the eight hectares area threshold, such as Couramoul Waterhole (approximately three hectares) (refer Figure 2 -13). With regards to this figure, note that billabong digitisation was only done for a portion of the site, and that only billabongs less than eight hectares are classified as Type Tp.

Additionally, this wetland type incorporates sedge and grass-dominated marshes on the wettest parts of the floodplains that are inundated for most or all of the year (Cowie et al. 2000). These marshes are widespread throughout the floodplain of all catchments within the site.

Type Ts: Seasonal/intermittent freshwater marshes/pools

This wetland type is composed of seasonal/intermittent freshwater marshes and pools on inorganic soils, including seasonally flooded meadows and sedge marshes (Figure 2-12). This wetland type is represented within the Ramsar site by vast tracts of freshwater wetlands that comprise the seasonally inundated floodplains. While vegetation is sparsely distributed during the dry season, floodplain wetlands are covered with one to two per metres of water and a multitude of plants during the wet season (Finlayson and Woodroffe 1996).

The floodplain wetlands are primarily sedge- and/or grass-dominated meadows that form complex spatial mosaics. Flora species comprising the floodplain wetlands are predominantly cosmopolitan in distribution (Taylor and Dunlop 1985), with characteristic species including wild rice Oryza spp., spike-rush Eleocharis spp), native hymenachne Hymenachne acutigluma and water couch Pseudoraphis spinescens (Russell-Smith 1995, Finlayson 2005). Commonly encountered waterlilies include blue waterlily Nymphaea violaceae, yellow snowflake lily Nymphoides hydrocharoides and white snowflake lily Nymphoides indica.

The outstanding value of freshwater floodplains to fauna is well-recognised, particularly with regards to waterbirds that congregate in large numbers.





Figure 2 16 Seasonally inundated floodplain at Mamukala. (source: BMT WBM)
Type Xf: Freshwater tree-dominated wetlands

This wetland type includes freshwater swamp forests, seasonally flooded forests and wooded swamps on inorganic soils (Figure 2-13). Although not listed in the 1998 RIS for either site, this wetland type is represented within the Ramsar site by swamp forests occurring along billabong and stream margins that are inundated by up to one metre of water during the wet season (Finlayson 2005).

Large areas of Melaleuca swamp forest occur within the site, such as at Marndoki, Big Swamp and Boggy Plain (refer to Figure 2 -13). Mapping by Brocklehurst and van Kerckhof (1994) shows that 74 113 hectares of Melaleuca is mapped in the Ramsar site, noting that these areas may have changed in the 15 years since the mapping was done.

Dominant species include broad-leafed paperbark Melaleuca viridiflora, Melaleuca cajuputi and white paperbark Melaleuca leucadendra, with other tree species commonly encountered including freshwater mangrove Barringtonia acutangula and screw pine Pandanus spiralis (Finlayson 2005).



Melaleuca forests are noteworthy in terms of the structural complexity that they add to the floodplain. In particular, Melaleuca forests offer roosting and nesting sites for birds such as magpie geese, green pygmy geese, cormorants and darters. Additionally, Melaleuca forests provide seasonal food resources such as nectar for birds (for example, honeyeaters and lorikeets) during the wet season. Melaleuca forests within the Ramsar site are highly productive and contribute a large amount of material to the detrital/debris turnover cycle on the floodplain (Finlayson et al. 1993).


Figure 2 17 Melaleuca swamp forest at East Alligator River (source: BMT WBM)
Type Y: Freshwater Springs

Although not listed in the 1998 RIS for either site, freshwater springs (Figure 2-14) are present within the Ramsar site. Some of these freshwater springs may support vegetation including screw pine Pandanus spp. communities or monsoon rainforest composed of ferns, palms and other tree species (for example, styptic tree Canarium australianum and banyan tree Ficus virens). Patches of monsoon rainforest are typically less than a few hectares in extent, but may occasionally form extensive tracts as riparian vegetation (Russell-Smith 1991). Permanent swamps on the floodplains may also be spring-fed, with paperbarks forming dense stands on these swamps (typically weeping paperbark Melaleuca leucadendra, cajeput M. cajuputi and broad-leaved paperbark M. viridiflora) (Brock 1993).

Vegetation mapping of monsoon forest has been provided by Parks Australia, and locations of a small number of freshwater springs within Kakadu National Park have been documented (by Buck Salau of Parks Australia, noting that some GPS points may be at a distance along the spring rather than at the source). These data have been overlaid to produce Figure 2 -20. However, in interpreting this figure it is important to note that locations of all springs have not been recorded, and that not all patches of monsoon forest are supported by freshwater springs (monsoon forest can also be associated with creeks and other sites of year round water availability). Furthermore, monsoon forest supported by springs is not necessarily at the source of the spring, but can be located along the length (for example, Benbunga Spring and Coonbanrbora Spring).

A number of permanent seeps are also located within the escarpment, but no empirical data describing their locations are available.



Figure 2 18 Freshwater spring (source: Buck Salau, Parks Australia)

I:\B17399_I_GML Kakadu Ramsar GWF\DRG\ECO_009_100310_Kakadu Billabongs.wor

Figure 2 19 Billabongs within South Alligator River catchment (source: BMT WBM 2009)

I:\B17399_I_GML Kakadu Ramsar GWF\DRG\ ECO_006_091117 Kakadu Forests Springs.wor
Figure 2 20 Freshwater springs and monsoon forest within the Ramsar site (source: Parks Australia unpublished data)

2.4.3Discrepancies with the 1998 RISs


A number of differences exist between the 1998 RISs for the historic (pre-merger) Ramsar sites and the current study in terms of the identification of wetland types that are present. However, differences do not represent an actual change in wetland types over time but instead reflect (i) differences in the interpretation of wetland typology descriptions; and (ii) an increase in knowledge of wetland type distribution since the preparation of the 1998 RISs.

Summarised from above, the following wetland types that were previously not identified for Kakadu National Park site but are now known to be present include the following:



  • Type D – Rocky marine shores

  • Type J – Coastal brackish/saline lagoons

  • Type K – Coastal freshwater lagoon

  • Type O – Permanent freshwater lakes

  • Type Xf – Freshwater tree dominated wetlands, and

  • Type Y - Freshwater springs.

The following wetland types that were previously identified as present within the site are not considered to occur in the site.

Type A: Permanent shallow marine waters

This wetland type incorporates marine waters that are less than six metres deep at low tide, including sea bays and straits. However, only waters above low water are included within the Ramsar site boundaries, and subtidal waters within the river channels are classified as estuarine waters (Type F). Therefore, this wetland type is not considered to be present in the Ramsar site.



Type R: Seasonal/intermittent saline/brackish/alkaline lakes and flats

Seasonal saline lakes are not thought to be represented within the Kakadu National Park Ramsar site.



Type Sp: Permanent saline/brackish/alkaline marshes/pools

Permanent saline marshes within the Ramsar site are not considered to be inland, but are rather classified as coastal wetlands (Type H).



Type Xp: Forested peatlands

This wetland type incorporates peat swamp forests and forested peatlands are not represented within Kakadu National Park. It is likely that inclusion of Type Xp in the 1998 RISs was an error that should rather have been Type Xf (described above).


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