Loss of coastal ecosystems

One of the big factors driving the decline in coastal ecosystems is the growing population in the Great Barrier Reef catchment.

Projections show nearly 1.5 million people will live in the Great Barrier Reef catchment by 2026 - an increase of 40 per cent on the current population.

There are around 100 urban settlements on the coast and islands, ranging from a few people to around 150,000 residents. In some of these areas, developments have led to a serious decline in key coastal habitats.

The breaking up of these habitats into progressively smaller patches, especially south of Port Douglas, is adversely affecting plants, animals and habitats in the inshore waters of the Great Barrier Reef.

In some locations 70 to 90 per cent of freshwater wetlands have been lost, while in areas north of Cairns, especially in Cape York, wetlands have been less disturbed due to their remoteness and fewer development pressures.

Without adequate planning and careful environmental management, population growth and intensification of development could increase pollution and sediments, decrease water quality, and change land and water connections.

Improvements in integrated planning, knowledge and compliance in managing coastal development are required to give coastal ecosystems greater protection.

The table below shows the extent of the remaining coastal ecosystems:

Coastal Ecosystems

Pre-European settlement

Total Area (km2)

Current

Total Area (km2)

Percentage remaining and condition

Coral reefs

Unknown but more extensive than today

2600

Extent of loss of coastal fringing reefs unknown. Around 50% decline in coral cover over the central reefs in the past two decades.

Lagoon floor

20,456

20,456

100 per cent remaining. Affected by poor water quality and fishing (trawling) in some areas.

Islands

Unknown vegetation. Mapping only completed for larger islands

Not calculated, but around 1050 islands of three types

More than 30 per cent national parks. Around 5 per cent of islands extensively modified by developments.

Open water

7200km3

7200 km3

Around 60 per cent of inshore waters regularly exceed Great Barrier Reef Marine Park water quality guidelines

Seagrasses

Unknown but believed to be more extensive than today

5668

Around 1 per cent cleared for port development. Water quality is affecting coastal seagrass communities south of Cooktown, although the extent of loss is unknown.

Coastline

7752km

7752km

Around 1 per cent of coastline is directly impacted by reclamations, groynes, jetties etc.

Estuaries (Mangroves and tidal saltmarshes)

4451

4076

92 per cent although some 30 per cent of tidal saltmarshes are affected by bunding.

Freshwater wetlands

1439

1241

86 per cent, with the health and condition varying between individual wetlands.

Forested floodplain

25,126

12,773

51 per cent with grazing occurring within some areas

Heath and shrublands

5361

5032

94 per cent condition unknown

Grass and sedgelands

12,366

5970

48 per cent condition unknown

Forests

239,608

145,381

61 per cent condition unknown

Woodlands

105,189

64,630

61 per cent with grazing occurring within some woodlands

Rainforests

26,995

16,756

62 per cent


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