2.5 Assessment summary — Biodiversity
Section 54(3)(b) of the Great Barrier Reef Marine Park Act 1975 requires ‘… an assessment of the current biodiversity within …’ the Great Barrier Reef Region. This assessment is based on two assessment criteria: • habitats to support species • populations of species and groups of species.
2.5.1 Habitats to support species
Outlook Report 2009: Assessment summary For most of the Great Barrier Reef, habitats appear to be intact. Some inshore habitats (such as coral reefs) have deteriorated, caused mostly by reduced water quality and rising sea temperatures. This is likely to have affected species that rely on these habitats. Little is known about the soft seabed habitats of the lagoon, open waters or the deep habitats of the continental slope. Current summary and assessment components Habitats to support species: Information on the condition and trend of habitats is highly variable with some well known (for example shallower coral reefs) and others poorly known, particularly habitats in remote areas or deep waters (for example Halimeda banks). The habitats of the northern third of the Region are believed to remain in very good condition and are able to support dependent species. Habitats in the southern two-thirds of the Region — especially those inshore — have deteriorated, particularly seagrass meadows and coral reefs. Islands: Some islands have been affected by recent extreme weather, invasive pests and weeds, marine debris, climate change and coastal development. Mainland beaches and coastlines: Some mainland beaches and coastlines have been modified especially around urban centres and ports. However most remain in a relatively natural state. Mangrove forests: Mangrove forests remain relatively stable and abundance is being maintained. Seagrass meadows: Many inshore seagrass meadows have declined since 2009, especially due to extreme weather events. Some meadows have shown early signs of recovery. Coral reefs: A series of disturbances has reduced coral cover in the southern two-thirds of the Region. Some areas are not yet showing signs of recovery. There are few indications of recent damage to deeper reefs. Lagoon floor: Recent reductions in trawling effort and better management have reduced the area of lagoon floor being affected by the fishery. There is likely to be localised damage from dredging, disposal of dredge material and anchoring. Shoals: There is limited information about shoals. They are likely to be impacted by fishing and anchoring activities. Halimeda banks: There is limited information about Halimeda banks. Given the habitat is remote and in deep water it is isolated from land-based impacts and is likely to be undisturbed. Assessment grade and trend Confidence
Very good Good Poor Very poor Grade Trend
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