2.3 Condition and trend — habitats to support species

Icon indicating the overall grade for this component is poor and improved since 2019.

Ten habitats are graded in terms of current condition and changes over the past 5 years with respect to impacts on dependent species. Halimeda bioherms and meadows, and continental slope habitats, remain in very good condition. Islands, mainland beaches and coastlines, mangrove forests, lagoon floor, and other banks and shoals, are assessed to be in good condition, and seagrass meadows have improved to good (borderline poor) since 2019. Coral reefs have improved to poor (borderline good), and the grades for component regions indicate that condition generally decreases from the north to the south of the Region.

The full assessment summary is in Section 2.5.1.

This section assesses the current condition (and trends in condition) of key habitats in the Region, from the tropics to the subtropics and from the coast to the continental slope and deep ocean. The depth and breadth of available biodiversity information varies enormously between components of the Reef ecosystem. In remote, deep and inaccessible areas, new examples of habitat are still being discovered (Figure 2.2). Investments in established and emerging technologies (Section 6.2.3) are helping researchers to document the extent and biological richness of these lesser-known habitats.⁶⁴

Figure 2.2

Reef geomorphological features

Left: A three-dimensional image of the Ribbon Reefs in the northern Great Barrier Reef identifying different habitat types. Right: A 500-metre-tall detached coral reef, which rises to 40 metres below sea level, was discovered off Cape York in October 2020. Sources: Dr Robin Beaman, James Cook University and Schmidt Ocean Institute.

The left side of this split image shows a three-dimensional image created from multibeam sonar data of the northern Great Barrier Reef. The image depicts different underwater geomorphological features such as the lagoon floor, mid-and outer-shelf reefs, mesophotic reefs and the continental shelf edge.

2. Biodiversity