Document ID: chunk:federal_register_of_legislation:F2016L00002:front:0:p53
Version: federal_register_of_legislation:F2016L00002
Segment Type: other
Provision Reference: 
Character Range: 154451–157374

Kakadu is particularly notable in encompassing almost the entire catchment and extent of some of the largest and most diverse river systems in northern Australia.

Kakadu's wetland environments begin in seepages, springs and small rock pools in the stone country. These headwater systems support a diverse range of endemic aquatic invertebrates, many with extremely restricted ranges. The springs and seepages may also support distinctive rainforest and perched swampland environments. From the stone country plateau to the lowlands, many of the river systems form spectacular waterfall systems as they pass over the sandstone escarpment. Some of these waterfall systems provide habitat to specialised plants, such as the threatened fern Cephalomenes obscurum.

The floodplains of the Wildman and the East, South and West Alligator rivers and seasonal creeks are vast and extend in almost unbroken tracts to the coast. They are reservoirs for floodwaters during the wet season, when the land is inundated by monsoonal rains. Rivers beginning in the stone country carry wet season floodwaters with nutrients and sand and silt eroded from rock structures to the floodplains each year. This process has been happening for thousands of years and continues today, making the floodplains and wetlands the most productive of Kakadu's habitats. The vegetation along creek and river channels is composed mainly of paperbark (Melaleuca quinquenervia) and water pandanus (Pandanus aquaticus). This is an area that was and still is used by Aboriginal people.

The freshwater floodplain environments, composed mainly of aquatic plants such as sedges, grasses and waterlilies, may be under water for many months, and during this time they can support the breeding activity of crocodiles and many waterbirds such as magpie geese. As the floodplains start to dry, crocodiles and vast numbers of waterbirds (sometimes many millions) seek refuge around remaining wetlands such as Yellow Water. Large numbers of migratory shorebirds also occur seasonally in parts of the floodplain. The great diversity of wetland habitats and the abundance of wildlife they support make Kakadu's floodplains of international significance and are the reason the park is listed as a wetland of international importance under the Ramsar Convention. The Ramsar Information Sheet (DSEWPaC 2011) provides more detail on Kakadu as a Ramsar site.

The coastal areas of the park are dominated by salt and mudflats and mostly lined with mangroves, which provide important breeding and nursery areas for a variety of fish including barramundi. The northern boundary of the park follows the low water mark of the 120 kilometre stretch of coastline that separates the park from the shallow waters of the Van Diemen Gulf. Gardangal (Field Island) and Djidbordu (Barron Island) lie near the mouth of the South Alligator River and are included within the park. Field Island