GREAT BARRIER REEF
// Outlook Report 2014
Outlook Report 2009: Overall summary of biodiversity
The Great Barrier Reef is one of the world’s best known and most complex natural systems and it continues to support extensive plant and animal biodiversity. This biodiversity is nationally and internationally important for the continued survival of many species. The sheer scale of the ecosystem means monitoring has focused on a few key habitats and species or groups of species, generally those that are iconic (such as coral reefs, seabirds), commercially important (such as seagrass meadows, coral trout) or threatened (such as dugongs, marine turtles). There are few long-term monitoring programs established and the baseline from which to make comparisons is different for each group studied. There is little detailed information about the status and trends of many habitat types within the Great Barrier Reef (for example the lagoon floor, shoals, Halimeda banks and the continental slope). However, there is some evidence of a small decline in coral reef habitat over recent decades. This may have already begun to affect species that depend on that habitat. Populations appear to be intact for the vast majority of species or groups of species in the Great Barrier Reef ecosystem. Latitudinal and cross-shelf biodiversity appears to be being maintained; however inshore species and their habitats adjacent to the developed coast are under more pressure than those both offshore and further north. Populations of a number of ecologically significant species, particularly predators (such as sharks, seabirds) and large herbivores (dugongs), are known to have seriously declined. Declines in species or groups of species have been caused by a range of factors, some of which have been addressed with evidence of recovery of some affected species (e.g. humpback whales, the southern Great Barrier Reef green turtle stock).
Biodiversity is the variety among all living things. It includes all natural variation, from genetic differences within a species to variations across a habitat or a whole ecosystem. The Great Barrier Reef is one of the world’s most diverse and remarkable ecosystems, with a wide range of habitats and many thousands of different species. The Reef’s biodiversity is the basis of its outstanding universal value recognised in its world heritage listing (Appendix 3). This assessment focuses on the broad habitats that make up the Reef’s ecosystem, plus the species and groups of species these habitats support. The species and habitats assessed are consistent with those in the Great Barrier Reef Outlook Report 2009 with the addition of shorebirds.
2.2 Legacies and shifted baselines
2.2.1 Legacy impacts
Some activities previously undertaken within what is now the Great Barrier Reef Region (the Region) and on its islands have had severe and long-lasting impacts on its biodiversity (Figure 2.1). Most of these activities stopped before the area’s protection as a marine park and its recognition as a world heritage area, but their legacy remains. These past activities need to be considered when assessing the current condition and trends of affected habitats and species. The most significant legacy impacts were from large-scale commercial harvesting, especially of long-lived species such as dugongs, marine turtles, crocodiles and humpback whales. • Dugongs were harvested for meat, bones, hide and oil.1 Initially, the number of dugongs taken by commercial harvesting was so high that a scarcity forced a closure of the industry in 1890.2 Large harvests resumed between the 1930s and 1969.3