Teoría de los Polisistemas en la construcción nacional de un

11.1 At a glance

Key drivers of fisheries productivity, high coastal biodiversity and community benefit are the extensive areas of seagrasses, mangroves, salt marsh and fresh to brackish wetlands along with the generally high quality near‐pristine nature of most of the Northern Territory coast and much of the catchments.

Overall there are about 150 estuaries in the Northern Territory with about 100 of these being tide‐dominated estuaries, creeks and flats.

About 140 of these 150 are in near pristine condition, another six are largely unmodified, three are modified and only two are extensively modified (Audit 2002).

Protectively managing all of the Northern Territory coast and its near‐pristine estuaries is essential and is more about controlling and directing any development that might occur. Site‐specific uses such as infrastructure for ports will need to be developed as the

Northern Territory capitalises on its mineral wealth. The challenge is to minimise impact and where possible offset any losses in habitat with works to improve overall catchment and estuary health.

The areas of improvement in habitat relate to minimising the risk of prior mining (the legacy mines) that was poorly rehabilitated, reducing excessive sediment export from grazing catchments, and minimising salinity intrusion and disturbance of fresh and fresh to brackish wetland systems caused by feral animals such as buffalo.

Various programs are already underway through the Northern Territory Government, the mining industry and the Natural Resources Management Group.

Therefore the emphasis of any investment in habitat within the Northern Territory is aimed more at the protective rather than the repair end of the spectrum and would probably involve support for further policy formulation within the government to maximise habitat protection while recognising that further development will occur. Policy frameworks in other states such as the Qld Fisheries Habitat Areas or Western Australian Offsets Policies might need to be evaluated and refined to meet the Northern Territory’s particular needs.

11.2 Northern Territory’s estuaries and inshore environments

Northern Territory estuaries are all located in the wet/dry seasonally contrasting tropics of Northern Australia with much of the rainfall being the wet season summer rainfall. Coastal catchments discharge to the Gulf of Carpentaria to the east, the Arafura Sea to the north and the Timor Sea to the west. In the north, monsoonal activity during the wet season is responsible for high rainfall. In the eastern and western regions a combination of weaker monsoonal effects and cyclonic activity influences annual rainfall. Flows in rivers discharging to estuaries are highly variable. Depending on the extent of the monsoon fronts and cyclonic activity the magnitude of annual floods varies between years. During the dry season freshwater discharge from rivers to estuaries often ceases.

the world, roosting areas for sea and waterbirds, and habitat for a wide range of tropical marine organisms. Along with Torres Strait, the seagrass beds support very large populations of dugong and turtle.

With the exception of the Darwin region and Nhulunbuy in the northeast, the Northern Territory coastline is sparsely populated, with a large proportion of estuaries remote and inaccessible by land. The population in these areas consists of indigenous communities and the homesteads of pastoral properties.

Approximately half of the Northern Territory coastline is indigenous land, with much of the remainder either freehold or pastoral lease. The dominant and often only land use in many catchments is grazing. Prior mining activity, being generally unmanaged and dating from when rehabilitation was not part of the mining lease requirements is a problem in some catchments and is known colloquially as the 'legacy mines'.

Northern Territory estuaries are valuable for traditional harvesting, eco‐tourism and pearling as well as commercial and recreational fisheries. The estuaries and associated extensive salt marshes of the Gulf of Carpentaria support the nationally important Gulf prawn and finfish fisheries.

11.3 Salinity inundation and loss of freshwater wetlands

Salinity encroachment is affecting and putting at risk a number of important freshwater fish habitats across the Northern Territory.

In rivers such as the Mary, Adelaide, South Alligator and Finniss as well as in important natural areas such as Kakadu National Park and Arnhem Land, salinity encroachment is having a devastating effect on freshwater billabongs, floodplains and paperbark swamps. It is already having a major effect on the productivity and biodiversity of these important and unique freshwater habitats.

The larger, longer‐term issue is that some of the Northern Territory’s most recognisable and loved assets such as Corroboree Billabong and the Kakadu wetlands are under serious threat from salinity inundation and encroachment.

11.4 Case study: the Mary River floodplains

The issue of salinity encroachment has been a major issue on the Mary River wetlands and floodplains for a number of decades. The cause, while mostly anthropogenic, is a complex mix of human actions including:

introduced species such as buffalo creating swim channels

failed and inappropriate human intervention in the form of barrages and weirs on the floodplain in an attempt to control tidal flows and

the deepening of the entrance channel to allow boat access by early industries such as buffalo and crocodile hunting.

Increased tidal flows have pushed further into freshwater areas killing off the freshwater‐ dependent vegetation and making the areas subject to high erosion risk and the deepening

Proposal 1: Salinity intrusion reduction

The key aim of this project is to undertake strategies and works to protect priority freshwater systems from salinity encroachment and inundation.

Following the assembly of all existing information, strategies and works activities will be detailed for selected at‐risk fresh water systems wetland floodplains and billabongs.

Strategies

Understanding what is at risk and developing plans of action for those areas where intervention is likely to succeed

Investment in preferably soft engineering options establishing mangroves and strengthening the coastal Chenier ridges while increasing efforts in feral animal control Proposal 2: Establishing the policy framework for ongoing habitat protection and management, northern Australia

The key aim of this project is to work cooperatively across the Queensland and Western Australian State Governments and the Northern Territory Government on a specific policy development activity around protecting existing the high quality fisheries habitat of northern Australia – fresh, fresh to brackish, estuarine and nearshore for the ongoing benefit of commercial, recreational and indigenous fishing. Offsets from specific points of development such as ports will contribute to ongoing maintenance activities, such as for example, providing certainty of funding for the ghost net initiative.

Strategies

As part of the policy development component of this Australia‐wide initiative, a specific project focusing on protecting and managing northern Australia’s near‐pristine fisheries habitats will be initiated.

Contributing expertise will include Queensland with their Fisheries Habitat Program, Western Australia with initiatives such as 'Royalties for the Regions' and Northern Territory with their knowledge and existing activities in habitat protection.

A key output will be to work towards fostering comparable policy and regulations across northern Australia for freshwater, estuarine and nearshore habitat protection and for management through such as development offsets.