Fresh water wetlands and associated floodplain ecosystem

Wetlands are vital to the Great Barrier Reef. They protect our shores from wave action, reduce the impacts of floods, absorb pollutants and provide habitat for animals and plants.

Wetlands are important in other ways as well. They purify water and are important for recreational activities. They form nurseries for fish and other freshwater and marine life and, because of this, they are important to Australia's commercial and recreational fishing industries.

Wetlands in the Great Barrier Reef catchment occur in many different forms. They may include flowing streams, billabongs, ephemeral lakes, dams or urban wetlands.

Each has its own unique ecosystem of plants and animals that depend on the wetland for food, water and shelter. In the tropics, wetlands are vital waterways that contribute to the health of the Great Barrier Reef catchment.

A large percentage of Australia’s wetlands have been degraded or lost since European settlement. Population increases and pressures in land-use practises in the catchment and coastal areas create competition for the use of wetland resources. Past agricultural activities have led to a loss of wetlands through drainage and infilling practices.

Queensland has extensive areas of potential acid sulfate soils located in low-lying areas near the coast. Acid sulfate soils contain iron sulphides that are normally constrained in a layer of waterlogged soil protected from contact with the air.

Draining of wetlands can expose acid sulfate soils to the air. This produces sulphuric acid that can acidify soil, ground and surface waters, which may drain into adjacent waterways reducing dissolved oxygen concentrations in the water column to critical levels impacting on aquatic species.

A range of development activities including the construction of canal estates, marinas, housing/industrial estates, roads, golf courses and aquaculture ponds have the potential to disturb acid sulfate soils.

Wetland connectivity

The report Freshwater Wetlands and Fish: Importance of Freshwater Wetlands to Marine Fisheries Resources in the Great Barrier Reef by Sunfish Queensland was prepared to identify coastal wetlands that are valuable for Great Barrier Reef fisheries.

The report identifies threats to these wetland ecosystems, and makes recommendations for the conservation of high value wetlands for fish species within the Great Barrier Reef catchment. The report is a valuable resource for the implementation of the Reef Water Quality Protection Plan.

Resources

The publication "Freshwater Wetlands to Marine Fisheries Resources in the Great Barrier Reef" by Sunfish Queensland has a range of useful information about wetlands: