Catchment management and the Great Barrier Reef

Area of Science:

• Marine Biology
• Environmental Science
• Ecosystem Management

Background:

• Coastal pollution in the Great Barrier Reef is primarily driven by agricultural runoff from adjacent catchments.
• Land use in these catchments is dominated by beef grazing and sugarcane cultivation.
• Pollutant loads, particularly nitrogen, have increased significantly, impacting marine ecosystems.

Purpose of the Study:

• To assess the current state of pollution in the Great Barrier Reef.
• To evaluate the effectiveness of existing legislation and management strategies.
• To highlight the urgent need for new mechanisms to mitigate pollution.

Main Methods:

• Analysis of land use in the Great Barrier Reef catchment area.
• Assessment of pollutant loads (sediment, nutrients, pesticides) in runoff.
• Review of current legislative and management frameworks (e.g., Great Barrier Reef Marine Park Act, Queensland legislation, integrated catchment management).

Main Results:

• Nitrogen runoff is four times the natural level from 150 years ago.
• Inshore reefs, seagrasses, and marine animals show significant effects and potential threats from pollution.
• Existing legislation and voluntary management strategies are largely ineffective in controlling pollutant loads.
• Pollutant loads are predicted to increase, with current regimes unlikely to prevent further degradation.

Conclusions:

• Current management approaches are insufficient to prevent the ongoing degradation of Great Barrier Reef ecosystems.
• There is an urgent need for new, effective mechanisms to manage agricultural pollution and protect the World Heritage Area.
• The lack of effective jurisdiction over catchments and the reliance on voluntary measures hinder pollution control efforts.