Many natural phenomena remain intact; declines in species have affected some.
The scenic beauty of the Reef’s islands is part of the property’s natural beauty. While the majority of the Whitsunday Islands are protected and managed as national parks, there have been some changes to island scenery, such as on resort islands. Hinchinbrook Island is protected and managed as a national park and retains its spectacular natural scenery. While many of the natural phenomena identified in the statement of outstanding universal value remain intact, others are likely to have deteriorated (see Chapter 2). Nesting numbers of at least two species of marine turtle have declined but are now recovering; there are signs of decline for nesting populations of some other marine turtle populations and some seabirds. There are anecdotal reports of severe declines in the number and condition of potato cod at the Cod Hole — a site famous for the species. In contrast, the number of migrating humpback whales is increasing. Protection of known fish spawning aggregations has improved, but most sites are unknown.
4.5.2 Major stages of the Earth’s evolutionary history
The Great Barrier Reef is the world’s largest coral reef ecosystem. While its overall condition has deteriorated, it remains an outstanding example of an ecosystem that has evolved over millennia. It represents the major stages in the Earth’s history, the record of life, geological processes in the development of landforms, and geomorphic and physiographic features.60 coral reefs are one of the Region’s key geomorphological features and it contains examples of all stages of reef development. The diversity of reef shape and size, for example fringing, shelf, ribbon and deltaic reefs (Figure 4.4), can be a function of substrate size, depth and, to a lesser extent, relative sea level history and carbonate productivity.61,62 Submerged reefs are important recorders of sea-level change 63, the Earth’s evolutionary history 63 and environmental change 64. Some corals are showing signs of decreased calcification rates, which has long-term implications for their future as geomorphological structures.65
The Region remains an outstanding example of evolutionary history.
Figure 4.4 Geomorphological features
The area adjacent to Cooktown and Princess Charlotte Bay contains many of the Region’s geomorphological features. These occur on the continental shelf, down the shelf edge and in the deeper water beyond. Image courtesy of Dr Robin Beaman,
Other geomorphological features in the Region that represent major stages of the Earth’s evolutionary history include: palaeochannels — past river channels that have been filled in over hundreds of thousands of years by sediment and later inundated by sea level rise. They comprise channel depressions and the associated sedimentary processes of erosion and deposition. They are now an element of groundwater flows from the Region’s catchment.66 Karstic features — landforms shaped by the dissolution of layers of soluble bedrock, such as limestone. In the Region, there are karstic channels on reefs that have been exposed during geological