While it may not be the largest World Heritage Area on Earth, the Great Barrier Reef is one of the better known. Its biological diversity is also unmatched by any other World Heritage Area.
Covering 348,000 square kilometres, this vast expanse is bigger than the United Kingdom, Holland and Switzerland combined and equivalent to 70 million football fields.
The World Heritage Area extends from the top of Cape York in north-east Australia to just north of Bundaberg, and from the low water mark on the Queensland coast to the outer boundary of the Marine Park, which is beyond the edge of the continental shelf.
About 99 per cent of the World Heritage Area is within the Great Barrier Reef Marine Park.
The remaining one per cent includes:
some 980 islands which are under Queensland jurisdiction
some internal waters or Queensland (for examples, some deep bays, narrow inlets or channels between islands)
intertidal areas protected by Queensland legislation
a number of small exclusion areas (state waters) around major ports and urban centres.
Within the World Heritage Area, there are more than 3000 separate coral reefs.
There are also 1050 islands and cays - these include 600 continental islands and 300 coral cays, while the remaining 150 islands are inshore mangrove islands which are important to the functioning and health of the Great Barrier Reef.
Together, the biodiversity and interconnectedness between species and habitats represents one of the richest and most complex natural ecosystems on earth.
The Great Barrier Reef was declared a World Heritage Area in 1981 because of its 'outstanding universal value'. This recognised the Reef as being one of the most remarkable places on earth, as well as its global importance and its natural worth.
The World Heritage Committee listed the Reef for all four natural criteria:¹
Be outstanding examples representing the major stages of the earth's evolutionary history
Forms the world’s largest coral reef ecosystem, extending over 14 degrees of latitude
Globally outstanding example of an ecosystem that has evolved over millennia
Environmental history recorded in the reef structure; for example, climatic conditions over many hundreds of years can be seen in old massive coral cores
Comprises about 3000 separate coral reefs, ranging from inshore fringing reefs to mid shelf reefs and shoals, exposed outer
Deep water features of the adjoining continental shelf includes canyons, channels, plateaux and abyssal plains
Be outstanding examples representing significant ongoing geological processes, biological evolution and man's interaction with his natural environment
Globally significant diversity of reef and island morphologies reflecting on-going geomorphic, oceanographic and environmental processes
Complex cross-shelf, longshore and vertical connectivity influenced by dynamic oceanic currents and ongoing ecological processes such as upwellings, larval dispersal and migration
Over 900 islands and cays; around 600 are continental (high) islands, 300 are coral cays in various stages of geomorphic development, with the remaining islands comprising mangrove islands that provide important ecological services
An ecosystem that has evolved over millennia with evidence of the evolution of hard corals and other fauna
Globally significant marine faunal groups include over 4000 species of molluscs; over 1500 species of fish; plus a great diversity of sponges, anemones, marine worms, crustaceans, and many others
Man's interaction with the natural environment illustrated by strong ongoing links between Aboriginal and Torres Strait Islanders and their sea country, including numerous shell deposits (middens) and fish traps, plus the application of story places and marine totems
Contain unique, rare or superlative natural phenomena, formations or features or areas of exceptional natural beauty, such as superlative examples of the most important ecosystems to man
Vast mosaic patterns of reefs providing an unparallel aerial panorama of seascapes and landscapes for example, Whitehaven Beach, Whitsunday islands, Hinchinbrook Island
One of the few living structures visible from space
Beneath the ocean surface, there is an abundance of shapes, sizes and colours, including spectacular coral assemblages (hard and soft corals) and >1500 species of fish
Globally important breeding colonies of seabirds and marine turtles, including Raine Island, the world’s largest green turtle breeding area
Superlative natural phenomena include the annual coral spawning, migrating whales, and significant spawning aggregations of many fish species
Be habitats where populations of rare or endangered species of plants and animals still survive
One of the richest and most complex natural ecosystems on earth, and one of the most significant for biodiversity conservation
Amazing diversity supports tens of thousands of marine and terrestrial species, many of which are of global conservation significance
Some 39 species of mangroves comprising 54 per cent of the world's mangrove diversity
~ 43,000km2 of seagrass meadows in both shallow and deep water areas, including 23 per cent of known global species diversity
Habitat for one of the world's most important dugong populations and six of the world's seven species of marine turtle
A breeding area for humpback whales, with at least 30 other species of whales and dolphins also identified
70 bioregions (broad-scale habitats) identified comprising 30 reef bioregions and 40 non-reefal bioregions; including algal and sponge gardens, sandy and muddy bottom communities, continental slopes and deep ocean troughs
The reef bioregions contain one third of the world's soft coral and sea pen species (80 species)
2000 species of sponges equalling 30 per cent of Australia's diversity in sponges
630 species of echinoderms (for example sea stars) equalling 13 per cent of the known global diversity
¹ These refer to the criteria for which the property was listed in 1981 – the wording of these has since changed.
The geology of the Great Barrier Reef tells the story of its earliest origins and today reveals the foundations it is built upon. The earliest Great Barrier Reef origins are held deep in its geology, telling the story of drifting continents of the foundations for its existence.
The first organism to accumulate limestone existed long before animals, including corals, evolved. About 3.7 billion years ago, blue-green algae formed stony mounts and columns. Some 1500 million years later, primitive sponge-like creatures became the next animals to produce limestone structures.
Around 25 million years ago, As Australia continued to drifting northwards into the tropics, small coral reefs had formed far offshore and a few reefs on the edge of Australia's continental shelf had also established in the very far north.
Approximately half a million years ago, the northern most part of the Great Barrier began to form and is now the oldest part of the Great Barrier Reef. Throughout its half-million year history, the Great Barrier Reef has gone through several ice-ages, called glacial periods, during which sea levels drop. These times alternated with warmer periods, called interglacial periods, where sea levels rise again. These cycles are caused by a wobble in the Earth's rotational axis that alters the amount of sunlight reaching parts of the planet.
Reef Discovery Course:
Keen to know what happens in the timeline of events? The Great Barrier Reef's Marine Park Authority's FREE Reef Discovery online course is a convenient online education package which aims to improve knowledge and understanding of the Great Barrier Reef World Heritage Area, its cultural connections, biological diversity, management and protection and how best to interpret this information to visitors. It is a one-stop-shop course that synthesises and describes the World Heritage values of the Reef and the latest science and management information in a contemporary format. This course is suitable for anyone with an interest in the Great Barrier Reef a passion for discovery. To receive your invitation, email reefdiscoverycourse@gbrmpa.gov.au with your details.
Outlook Report 2019:
Every five years, we publish an Outlook Report that examines the Great Barrier Reef’s health, pressures, and likely future. We also produce an in brief summary of the report. The 2019 report is the third comprehensive report in the series, and identifies the Great Barrier Reef Region still faces significant pressures ranging in scale from local to global.
The processes that gave the Great Barrier Reef its geological World Heritage value, lay the foundations for the broad variety of habitats that gave the Great Barrier Reef its ecological World Heritage values.
The Great Barrier Reef ecosystem is big, vast, spanning 14 degrees of latitude of the Earth's southern hemisphere and extending up to 300km off the Australian coastline, covering in total about 345,000 square kilometres of water.
The Great Barrier Reef ecosystem also includes 385,000 square kilometres of land catchment that delivers rain runoff to the inshore part of the marine ecosystem.
The only part of the land component of this ecosystem that is World Heritage is the 8,944 square kilometre Wet Tropics Region.
There are 14 key habitats.
The Great Barrier Reef is more than just coral reef. It is a complex ecosystem made up of many different habitats. Pars of the Great Barrier Reef ecosystem includes the catchment on land and the deep ocean. They are are all connected by the water cycle.
Coral reefs are the cornerstone of the reef ecosystem and the most well know habitat for visitors to the Great Barrier Reef. Despite covering only about six per cent of the Great Barrier Reef Marine Park regional, their species diversity, habitat value and natural beauty are major contributors the Great Barrier Reef's outstanding universal value as a world heritage area.
Surprising reef fact: Up until 2017 the official number of individual reefs was 3000, covering approximately 6-7 per cent of the Great Barrier Reef, But that was not the whole story. Detailed sonar mapping has recently revealed that there are actually roughly 3800 reefs meaning there is more coral habitat than currently mapped.
Reef Discovery Course:
There is so much information available on ecological values in the Great Barrier Reef's Marine Park Authority's FREE Reef Discovery online course. It is a convenient online education package which aims to improve knowledge and understanding of the Great Barrier Reef World Heritage Area, its cultural connections, biological diversity, management and protection and how best to interpret this information to visitors. It is a one-stop-shop course that synthesises and describes the World Heritage values of the Reef and the latest science and management information in a contemporary format. This course is suitable for anyone with an interest in the Great Barrier Reef a passion for discovery. To receive your invitation, email reefdiscoverycourse@gbrmpa.gov.au with your details.
Outlook Report 2019:
Every five years, we publish an Outlook Report that examines the Great Barrier Reef’s health, pressures, and likely future. We also produce an in brief summary of the report. The 2019 report is the third comprehensive report in the series, and identifies the Great Barrier Reef Region still faces significant pressures ranging in scale from local to global. The Outlook Report provides valuable information of the status of the ecological values of the Great Barrier Reef.
Biodiversity is the variety among living things and the Great Barrier Reef's biodiversity forms part of the basis of its outstanding universal value recognised in its world heritage listing.
Biodiversity 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 range of habitats and many thousands of different species.
Every species, in its effort to survive long enough to reproduce, affects the ecosystem in a particular way. In attempting to understand how ecosystems work , scientists describe these affects as 'services' such as decomposing waste or grazing away algae, that keep the ecosystem functioning.
Why is biodiversity so important?
Biodiversity is not just nice, it is necessary. Nothing can survive in isolation. Even some of the basic ecosystem services include the maintenance of water, air and soil quality - factors important for much of life of Earth. If services stopped, an ecosystem could collapse to a different state, with loss of many species. Biodiversity is the source of all of our foods, and many of our medicines and industrial products are derived from animals and plants. Biodiversity is important for our recreation and our physical and spiritual well-being. It is the reason people travel to visit the Great Barrier Reef, to see life in abundance. A diverse environment has a profound aesthetic appeal to all human beings.
Reef ecology - Food webs: All reef plants and animals are part of an intricate , functional and interconnected food web. Impact on any population has flow on effects to other reef species. Depending on their functional ecosystem role, the loss of a species population can have enormous consequence. Basic ecological roles include Primary Producers, First Order Consumers, Second Order Consumers, Scavengers and Decomposers.
Reef ecology - Beyond food webs: Understanding that the Great Barrier Reef ecosystem is a giant food web, there are a range of related processes to understand to help share how the system works. Some critical examples of these processes include the Zooxanthellae symbiotic relationship with coral and other animals, the fact that bacteria are everywhere, nutrients are quickly recycled and connectivity is a fundamental driver of Reef health.
Reef Discovery Course:
Interested to know more on zooxanthellae, bacteria, nutrients, zooplankton and phytoplankton or biodiversity and the World Heritage Outstanding universal values? Our FREE Reef Discovery Course is a one-stop-shop course that synthesises and describes the World Heritage values of the Reef and the latest science and management information in a contemporary format. This course is suitable for anyone with an interest in the Great Barrier Reef a passion for discovery. To receive your invitation, email reefdiscoverycourse@gbrmpa.gov.au with your details.
Outlook Report 2019:
Every five years, we publish an Outlook Report that examines the Great Barrier Reef’s health, pressures, and likely future. We also produce an in brief summary of the report. The 2019 report is the third comprehensive report in the series, and identifies the Great Barrier Reef Region still faces significant pressures ranging in scale from local to global. The Outlook Report provides valuable information of the status of the biodiversity values of the Great Barrier Reef.
The outstanding universal value has been maintained, but it is increasingly challenged. One criterion — habitats for the conservation of biodiversity — is assessed as poor (as identified in the Authority's 2019 Outlook Report). Widespread coral mortality (as a result of sea temperature extremes in combination with predation by crown-of-thorns starfish) and impacts from severe cyclones, have affected the aesthetics and natural beauty of some parts of the Region above and below the water. There has been alteration of some processes important to major stages of the Earth’s evolutionary history, such as reef building, sea-level rise and sea temperature. Climate change remains the greatest risk to the outstanding universal value of the World Heritage Area and its integrity.
The Great Barrier Reef was inscribed on the World Heritage List in 1981 and included on the National Heritage List in 2007. The continued occupation of indigenous people in the land and sea country for 60,000 years of what is now known as the Great Barrier Reef is an outstanding global example of a human culture interacting with the natural environment.
Cultural heritage values are both tangible and intangible - they are the physical traces left behind by past inhabitants as well as languages, stories, story places, place names, and the feeling of connection that people have for their country. These values provide insight into how Traditional Owners see the Great Barrier Reef, including its landscape, plants and animals.
Traditional practices that are still undertaken today continue to be passed onto subsequent generations.
The historical heritage of the Great Barrier Reef relates to the occupation and use of an area since the arrival of European and other migrants. Historical heritage therefore is not part of the four Natural Criteria of World Heritage values through the creation of this cultural environment.
Reef Discovery Course:
Keen to know on heritage values? The Great Barrier Reef's Marine Park Authority's FREE Reef Discovery online course is a convenient online education package which aims to improve knowledge and understanding of the Great Barrier Reef World Heritage Area, its cultural connections, biological diversity, management and protection and how best to interpret this information to visitors. It is a one-stop-shop course that synthesises and describes the World Heritage values of the Reef and the latest science and management information in a contemporary format. This course is suitable for anyone with an interest in the Great Barrier Reef a passion for discovery. To receive your invitation, email reefdiscoverycourse@gbrmpa.gov.au with your details.
Learn more about the Great Barrier Reef Marine Park Authority's Indigenous rangers capacity building program.
Outlook Report 2019:
Every five years, we publish an Outlook Report that examines the Great Barrier Reef’s health, pressures, and likely future. We also produce an in brief summary of the report. The 2019 report is the third comprehensive report in the series, and identifies the Great Barrier Reef Region still faces significant pressures ranging in scale from local to global.
The Great Barrier Reef was inscribed on the World Heritage List in 1981 and included on the National Heritage List in 2007. The outstanding universal value has been maintained, but it is increasingly challenged. The Great Barrier Reef remains whole and intact, however, significant components that underpin all four natural world heritage criteria for which the World Heritage Area was inscribed have deteriorated since its inscription.
One criterion — habitats for the conservation of biodiversity — is assessed as poor (as identified in the Authority's 2019 Outlook Report). Widespread coral mortality (as a result of sea temperature extremes in combination with predation by crown-of-thorns starfish) and impacts from severe cyclones, have affected the aesthetics and natural beauty of some parts of the Region above and below the water. There has been alteration of some processes important to major stages of the Earth’s evolutionary history, such as reef building, sea-level rise and sea temperature. Climate change remains the greatest risk to the outstanding universal value of the World Heritage Area and its integrity.
Indigenous heritage values include tangible and intangible heritage and are interlinked with the condition of the Reef’s natural components. The effects of acute and chronic disturbances across the Region over the past five years have affected the condition of the Region’s Indigenous heritage value, some of which is irreplaceable (for example, songlines). The very limited available evidence in both 2014 and 2019 for Indigenous heritage value constrains confidence in both grade and trend.
Historic heritage values Five properties in the Region are on the Commonwealth Heritage List: Low Island and Low Islets lightstation (including its significance to Kuku Yalanji and Yirrganydji Traditional Owner groups), Dent Island lightstation, Lady Elliot Island lightstation, North Reef lightstation and Shoalwater Bay Military Training Area. The places are well maintained and have been identified and included in relevant inventories.
Historic heritage components include other lightstations, shipwrecks, aircraft wrecks and other places of historic significance. Published condition and trend data are lacking for most sites, so confidence in the grade and trend is limited or inferred. Positive progress has been made towards gathering evidence on shipwrecks and aircraft wrecks.
The significant discovery in late 2018 of the precise location of the shipwreck of the Martha Ridgway increased the baseline data for this component. The vessel was lost over 170 years ago on a voyage from New Zealand to Bombay (now Mumbai). The Martha Ridgway shipwreck was found on the reef of the same name using a variety of survey methods and remote sensing equipment, including aerial surveys (drone), magnetometer surveys and visual census. The wreck is significant for many reasons, including its size and its association with the historic Raine Island beacon.
Other heritage values: Social, aesthetic and scientific values are included in this assessment. The significance of the World Heritage Area still transcends national boundaries and remains a source of pride for the Australian public broadly. The social heritage value of the Region is considered to be in good condition. How society thinks and feels about the state of the Reef is at the heart of the Region‘s social heritage value. In 2017, climate change, pollution and agricultural run-off were considered by Australian residents to be the biggest threats to the Reef. A 2017 survey of approximately 3900 people living close to or deriving benefit from the Reef (local and national residents, tourists, tourism operators, and commercial fishers) highlighted the wider community’s concern about the declining condition of the Reef, and a strengthening connection to its environment and natural beauty.
