GREAT BARRIER REEF
// Outlook Report 2014
3.7 Assessment summary – Ecosystem health
Section 54(3)(a) of the Great Barrier Reef Marine Park Act 1975 requires ‘… an assessment of the current health of the ecosystem within the Great Barrier Reef Region and of the ecosystem outside that region to the extent that it affects that region’. This assessment is based on five assessment criteria: • physical processes • chemical processes • ecological processes • terrestrial habitats that support the Great Barrier Reef • outbreaks of disease, introduced species and pest species.
3.7.1 Physical processes
Outlook report 2009: Assessment summary The physical processes of the Great Barrier Reef are changing, in particular sedimentation and sea temperature. Further changes in factors such as sea temperature, sea level and sedimentation are expected because of climate change and catchment runoff.
Current summary and assessment components Physical processes: The condition of all physical processes has declined since 2009. Further changes in processes such as sea temperature, sea level, cyclones and wind, freshwater inflow, waves and currents are expected under climate change projections. Reduced sediment loads entering the Region are likely to improve the processes of sedimentation and light availability in the longer term. Currents: There is evidence of intensified flow and accelerated warming in the East Australian Current. Cyclones and wind: Between 2005 and 2013, there were six category 3 or above cyclones in the Region. There is emerging evidence of increases in wind strength Australia-wide. Freshwater inflow: Large volumes of freshwater have entered the Region in the past five years, including record flows for some rivers. Sedimentation: Sediment loads entering the Region continue to be at least double those occurring before European settlement. Improved land management is beginning to reduce sediment input, but measurable improvements in the Region may take decades. Sea level: The fastest rates of sea level rise in Australian waters are in northern areas. Average sea level rise in the Region is 3.1 millimetres per year. Sea temperature: The ocean has warmed substantially over the last century. Most of the warmest years have been in the past two decades. Light: It is likely that light availability has decreased substantially in the inshore areas of the southern two-thirds of the Region due to land-based runoff and extreme weather.
Assessment grade and trend
Very good Good Poor Very poor Grade Trend
i i i i i i i
Trend since 2009
There are no significant changes in processes as a result of human activities.
There are some significant changes in processes as a result of human activities in some areas, but these are not to the extent that they are significantly affecting ecosystem functions.
There are substantial changes in processes as a result of human activities, and these are significantly affecting ecosystem functions in some areas.
There are substantial changes in processes across a wide area as a result of human activities, and ecosystem functions are seriously affected in much of the area.
h n i 0
Improved Stable Deteriorated No consistent trend
Adequate high-quality evidence and high level of consensus Limited evidence or limited consensus Inferred, very limited evidence