Rock art, stromatolites, and mass spawning
I. Map boundaries: 20 to 30 degrees South; 108 to 117 degrees East
II. Country (Provinces--Regions): Australia (Western Australia—Gascoyne, Mid West, Pilbara, and Wheat Belt regions).
III. Overview
This map area encompasses deserts and savannas of the Western Australia coastline. The northern and central areas are arid; however, occasional summer tropical storms can cause flooding as happened in December 2010 around Carnarvon. The area around Shark Bay received in excess of nine inches of rain from a tropical storm. In addition, the coastal areas from Shark Bay southward receive winter rains, which support a more savanna-like vegetation and spring wildflower displays. The southern portions of the map area, from Shark Bay southward, are dominated by eucalyptus trees in the flora, while the northern, more desertic areas, are dominated by acacia shrubs. This area was not always a desert. Until three million years ago, northwestern Australia was covered with rainforest. At this time, the Indonesian archipelago rose from the ocean floor, changing ocean currents and blocking warm water traveling south along the Australian coast. This led to the decline of precipitation in Australia, and was the death blow to rainforest vegetation (Perkins 2011).
In the northeast corner of the map, the Dampier Archipelago consists of 42 island nature reserves covered with the spinifex grass characteristic of the Pilbara shrublands. The islands and the nearby Murujuga peninsula are the site of the world’s largest known collection of rock art. Images of birds, marine life, terrestrial life including now-extinct species, and human figures are found, along with stone arrangements. These are believed to be dreaming and ceremonial sites of the Ngarda-Ngarli peoples.
Ningaloo Reef, the second longest contiguous reef system in the world and the only major reef on the west coast of any continent, extends for more than 250 km parallel to the coast in the Gascoyne region of Western Australia. It is the site of one of nature’s most spectacular mating rituals. After the March full moon at neap tide, when tidal motion is at a minimum, between 8 and 10 p.m., the corals spawn all at once in the still waters. Wind-driven waves later appear to wash the larvae out to sea. But sometimes, the waves do not appear. The growing coral larvae deplete the oxygen in the lagoon, leading to asphyxiation of the larvae, fish and other animals, and the parent corals themselves. Since its discovery in 1989 at Ningaloo, the mass suicide has been observed at other reefs (Richardson 1994).
The Ningaloo Marine Park, together with adjacent properties at the Cape Range National Park and Muiron Islands Marine Reserve, make up a world heritage site. Ningaloo Reef supports 200 species of coral, 500 species of fish, 600 species of mollusk, and 90 species of echinoderms. There are large populations of dugongs, marine turtles, whales, and whale sharks. Adjacent to the reef, terrestrial habitats of the Carnarvon xeric shrublands are found inland. Cape Range National Park has a limestone karst landscape, supporting 500 caves and sinkholes with rare subterranean aquatic fauna. These rare fauna have evolved in isolation as the Australian continent separated from Gondwana and became increasingly arid as it moved north.
To the south of Ningaloo is Shark Bay, another world heritage site. Constituent units include the Dirk Hartog Island National Park, Francois Peron National Park, Hamelin Pool, and Bernier and Dorre Islands nature reserves. The bay itself is a marine park which supports vast herds of dugong, sharks, turtles, and whales. The world’s largest seagrass beds are here.
Some of the oldest rocks in the world are limestones which have peculiar layers arranged in wavy, crinkled and onionlike forms. They are most common from the Late Precambrian to early Paleozoic era. These structures include branched growths, columns half a meter in diameter and several meters tall, and reeflike masses. With the appearance of burrowing invertebrates, the numbers of these peculiar structures declined (Awramik 1971). At the Hamelin Pool Marine Nature Reserve, the most diverse and abundant stromatolites in the world may be found in the shallow water. Stratomatolites are formed when cyanobacteria band together and produce a sticky gel, which traps sediments and builds layers. The stromatolites in Hamelin Pool orient themselves toward the sun, providing the possibility that fossilized stromatolites can be used to determine the latitude at which they were fossilized (Awramik and Vanyo 1986). In 2010, Chen et al. isolated a unique fifth form of chlorophyll from cyanobacteria in Shark Bay. For most of the past 60 years, chlorophyll was thought to occur in four forms. The new chlorophyll extends oxygenic photosynthesis into the infrared spectrum.
Since 1982, the Shark Bay Dolphin Project has provided scientific research on a small group of wild dolphins. The research has revealed that dolphins lead a complex social life which is only closely paralleled in humans. At nearby Shell Beach Conservation Park, billions of tiny shells along the shoreline of Shark Bay have created a beach one km wide and 10 m deep.
To the south of Shark Bay is the Southwest Australia savanna ecoregion, extending from the western shores of Shark Bay southward across the Mid West region. Kalbarri, LeSueur, and Alexander Morrison National Parks are the heart of the wildflower viewing region. Showy flowers of the Proteaceae plant family are common. The region is characterized by winter rains, which create carpets of wildflower displays.
Inland in the Western Australia mulga shrublands ecoregion, the arid expanse is viewed as an ideal site for radiotelescopes due to excellent sky coverage, radio quietness, and benign tropospheric conditions. The Murchison Radioastronomy Observatory is one of two sites for the proposed International Square Kilometer Array, the largest astronomical instrument ever built (Koenig 2006a, 2006b). The Australian Square Kilometer Array Pathfinder is under construction at a site near the Murchison River, an intermittent watercourse. It will search for faint radio signals from distant galaxies.
IV. Terrestrial Ecoregions of the Australasia Biome
A. Mediterranean Forests, Woodlands, and Shrub
AA1209, Southwest Australia savanna. Widely spaced eucalyptus savanna merges into acacia (wattle) as it moves inland toward sandplains. This is famous for wildflowers including Banksia, kangaroo paws (Anigozanthos), Grevillea, and orchids. Nectar feeders such as possums and wallabies are part of the mammal fauna. Found on Dirk Hartog Island, Edel Land, the Zuytdorp Cliffs and the Mid West region of Western Australia.
B. Deserts and Xeric Shrublands
AA 1301, Carnarvon xeric shrublands. This arid coastal expanse is characterized by acacia and gidgee trees. Notable birds are grasswren and red-tailed black cockatoo. This region encompasses coastal Western Australia from Shark Bay north to Exmouth Bay and includes parts of the Gascoyne, Mid West, and Pilbara regions.
AA1307, Pilbara shrublands. Spinifex grass grows in clumps and rings, called hummocks. Occasional mulga (acacia) trees dot the area. This ecoregion is found in the Pilbara region and includes the offshore Barrow Island, Montebello Islands, and Dampier Archipelago as well as the watersheds of the Fortescue and Cane rivers.
AA 1310, Western Australian Mulga shrublands. The drought-adapted acacia shrub, along with emu bush, hoploush, and Cassia are found here. A grassy understory is found beneath the shrubs. Honeyeaters, kookaburra, and mole marsupial are characteristic animals. Found inland in the south of the Pilbara region, east Gascoyne region, and north Mid West region of Western Australia.
V. Freshwater Ecoregions of the World
Australia and Pacific Region
A. Temperate Coastal Rivers
801. Southwestern Australia. In the southeastern corner of the map, more permanent rivers lead to a diverse fish fauna of Galaxiidae, perches, and eel-tailed catfish (Plotosidae) familes. There are also endemic turtles and crayfishes. This region extends along the coast and includes the Arrowsmith and Moore rivers on the map.
B. Xeric Freshwaters and Closed Basins
802. Pilbara. Extends north along the coast from the Greenough River, including the Murchison, Gascoyne, Ashburton, and Fortescue river drainages. All rivers are intermittent but support endemic fish such as Milyeriaga (blind cavefish), Craterocephalis (hardyheads), and Leiopotherapan (grunter).
804. Paleo. This area has isolated saline lakes but no permanent, fish-inhabited waterways and includes inland portions of the Mid West, Gascoyne, and Pilbara regions.
VI. Marine Ecoregions of the World
A. Central Indo-Pacific Realm, Northwest Australian Shelf Province
144. Exmouth to Broome. Found from the Muiron Islands northward along the Pilbara region of Western Australia.
145. Ningaloo. Found from the Cape Range National Park southward to about Cape Cuvier in the Gascoyne region of Western Australia.
B. Temperate Australia Realm, West Central Australian Shelf Province
210. Shark Bay. Found from Cape Cuvier southward to Kalbarri National Park in the Gascoyne and Mid West regions of Western Australia.
211. Houtman. Found from Kalbarri National Park southward in the Mid West region of Western Australia.
VII. World Heritage Sites
Ningaloo Coast. The best developed fringing reef in the world extends for more than 200 km along the Western Australia Coast. Inland, the Cape Range contains a globally significant karst area formed as a result of seawater incursion into the limestone substrate. The aquatic community of the Bundera sinkhole is unique in the southern hemisphere for its remipede crustaceans. The world heritage area includes Bundegi Coastal Park on Exmouth Peninsula, Cape Range National Park, Jurabi Coastal Park on Exmouth Peninsula, Learmonth Air Weapons Range, Muiron Islands Marine Management Area, and Ningaloo Marine Park, all in the Gascoyne region. Individual units are described in the points of interest listing.
Shark Bay. Listed for natural beauty, earth history, biological diversity, and ecological processes, Shark Bay is known for the most diverse and abundant examples of living stromatolites; a unique hydrologic system with three salinity zones and the world’s largest seagrass beds; the world’s largest dugong population; and endemic plants, marine animals, and terrestrial animals. There are 28 endemic plants, five endemic mammals, whales, and sea turtles. The world heritage area includes Bernier Island Nature Reserve, Dirk Hartog Island National Park, Dorre Island Nature Reserve, Edel Land, Faure Island, Francois Peron National Park, Freycinet Island, Hamelin Pool Marine Nature Reserve, Quoin Bluff, Shark Bay Marine Park, Shell Beach Conservation Park, Wooramel Coast, and Zuytdorp Cliffs, all in the Gascoyne region of Western Australia. Individual units are described in the points of interest listing.
VIII. Points of Interest
Alexander Morrison National Park, Mid West region. This park is noted for a diversity of endemic wildflowers, including Banksia and Myrtaceae species. Terrestrial ecoregion 1209.
Mount Augustus National Park, Gascoyne region. A 717-m peak rising above arid shrubland is the biggest solitary rock in the world. The park has rock art and permanent water. Terrestrial ecoregion 1310.
Barrow Island Marine Park and Marine Management Area, Pilbara region. This reserve protects coral reefs and sea turtle breeding areas. Barrow Island is an Important Bird Area for pied oystercatcher, spinifexbird, white-winged fairy wren, pied oystercatcher, and grey-tailed tattler. Terrestrial ecoregion 1307 and marine ecoregion 144.
Bernier Island Nature Reserve and Dorre Island Nature Reserve, Gascoyne Region. Part of Shark Bay World Heritage Area. Four mammals are endemic to Bernier and Dorre islands: Shark Bay mouse, banded hare-wallaby, western barred bandicoot, and rufous hare-wallaby. Terrestrial ecoregion 1301 and marine ecoregion 210.
Bundegi Coastal Park, Gascoyne Region. Part of Ningaloo Coast World Heritage Area. Terrestrial ecoregion 1301 and marine ecoregion 145.
Cape Range National Park, Gascoyne Region. Part of Ningaloo Coast World Heritage Area. Deep canyons and gorges mark this globally significant karst area with rare invertebrates in the Bundera sinkhole. Rock wallabies, kangaroos, emus, echidnas, and lizards are common animals. Offshore, the Cape Range Canyons support upwellings that help to maintain the biological diversity of the Ningaloo Reef system. Terrestrial ecoregion 1301 and marine ecoregion 145.
Coalseam Conservation Park, Mid West Region. Botanically diverse acacia shrubland and ancient marine fossils along the Irwin River are protected. The notable wildflower display is carpets of pink, white, and yellow everlastings. Terrestrial ecoregion 1209.
Dalgaranga, Mid West Region. A small impact crater from about 270,000 years ago. Terrestrial ecoregion 1310.
Dampier Archipelago Island Reserves and Burrup Peninsula (Murujuga), Pilbara region. The largest collection of petroglyphs in the world (up to a million in number) contains drawings of kangaroos, emus, and thylacines, an extinct marsupial. The 42 islands have been the subject of an ongoing marine biodiversity inventory, with 4,500 species recorded to date, and are rich in brittle stars, sea cucumbers, starfish, sea urchins and sea lilies. They are also known for sea turtle nesting. Terrestrial ecoregion 1307 and marine ecoregion 144.
Dampier Saltworks, Pilbara region. An Important Bird Area for red-necked stint and red-capped plover. Terrestrial ecoregion 1307.
Denham, Gascoyne region. Location of the Shark Bay World Heritage Discovery Centre. Terrestrial ecoregion 1301.
Dirk Hartog Island National Park, Gascoyne region. Part of Shark Bay World Heritage Area. Cape Inscription, at the northern tip, is the location of the Dirk Hartog Landing Site by the Dutch East India Company. This first European landing in Australia was in 1616. The island is characterized by steep cliffs on the west side and low limestone plains on the east side. Rare sandhill frogs and the black and white fairy wren are found here, as are breeding loggerhead turtles. Surges of waves into coastal rocks create blowholes, which are a scenic feature. Quoin Bluff on Dirk Hartog Island is an Important Bird Area for nesting pied cormorant. Terrestrial ecoregion 1209 and marine ecoregion 210.
Dongara, Mid West region. The Irwin River Nature Trail is a wildflower viewing area and also is noted for black swans, pelicans, and cormorants. Terrestrial ecoregion 1209.
Edel Land and the Zuytdorp Cliffs, Gascoyne region. Part of Shark Bay World Heritage Area. Scenic limestone cliffs 200 km long and 200 m high are found to the west and south of Shark Bay. Terrestrial ecoregion 1209 and marine ecoregion 210.
Exmouth Gulf, Gascoyne and Pilbara regions. The mangroves extending north along the coast are an Important Bird Area for grey-tailed tattler and pied oystercatcher. Marine ecoregion 144.
Faure and Pelican Islands, Gascoyne region. Part of Shark Bay World Heritage Area. An Important Bird Area with breeding fairy tern, pied oystercatcher, and red-necked stint. Terrestrial ecoregion 1301 and marine ecoregion 210.
Francois Peron National Park, Gascoyne region. Part of Shark Bay World Heritage Area. Red sandy plains have acacias and shrubs typical of the desert, while flowering plants from temperate Australia such as Hakea and Grevilla reach their northern limits. Gypsum claypans called barridas are interspersed throughout the park. Just south of the park is Monkey Mia, home of dolphin research activities (described above in the overview). Terrestrial ecoregion 1301 and marine ecoregion 210.
Freycinet Island, Gascoyne region. Part of Shark Bay World Heritage Area. An Important Bird Area for nesting pied cormorant. Terrestrial ecoregion 1301 and marine ecoregion 210.
Mount Gibson Sanctuary and Charles Darwin Reserve, Mid West and Wheat Belt regions. These are Important Bird Areas for malleefowl and western corella. Terrestrial ecoregion 1209.
Hamelin Pool Marine Nature Reserve, Gascoyne Region. Part of Shark Bay World Heritage Area. The stromatolites are accessible by a boardwalk. Also found here are the Hamelin cockle, a species of mollusk which is so prolific that building blocks can be cut from shells on the beach. Marine ecoregion 210.
Houtman Abrolhos Islands, Mid West region. The 122 coral islands are the most important seabird nesting site in the eastern Indian Ocean (an Important Bird Area), with up to one million pairs of seabirds, and are home to rare tropical and temperate fish species. The Wallabi group of islands is the site of the Batavia shipwreck in 1629. The flagship of the Dutch East India Company ran aground on a reef. Survivors built huts on West Wallabi Island. An unexpected series of events ensued, including mutiny and murders. Of 332 people, only 116 survived. Terrestrial ecoregion 1209 and marine ecoregion 211.
Jurabi Coastal Park, Gascoyne region. Part of Ningaloo Coast World Heritage Site. Terrestrial ecoregion 1301 and marine ecoregion 145.
Kalbarri National Park, Mid West Region. The lower Murchison River has created a gorge with red- and white-banded gorges, sea cliffs, and arches. The area is noted for spring wildflowers (Banksia, Grevillea, and kangaroo paw (Haemodoraceae family), grey kangaroos, and emus. Humpback whales and dolphins can be seen offshore. Terrestrial ecoregion 1209 and marine ecoregion 210.
Karara and Lochada, Mid West region. This is an Important Bird Area for malleefowl and western corella. Terrestrial ecoregion 1209.
Kennedy Range National Park, Gascoyne region. A mesa with gorges, seasonal waterfalls, and ancient dune fields on top of the flat-topped mountain. Terrestrial ecoregion 1301.
Koobabbie, Mid West and Wheat Belt regions. This is an Important Bird Area for Carnaby’s black-cockatoo and western corella. Terrestrial ecoregion 1209.
Learmonth Air Weapons Range, Gascoyne region. Part of Ningaloo Coast World Heritage Site. Terrestrial ecoregion 1301.
LeSueur National Park, Mid West region. A mesa in the northern sand plains has shrublands and is known as a wildflower viewing area with 820 species. Terrestrial ecoregion 1209.
Lake MacLeod, Gascoyne region. This intermittent lake is an Important Bird Area for fairy tern, red-necked stint, curlew sandpiper, banded stilt, red-necked avocet, red-capped plover, and dusky gerygone. Terrestrial ecoregion 1301.
Millstream-Chichester National Park, Pilbara region. Escarpments and tree-line watercourses from springs along the Fortescue River provide an oasis in the desert. Terrestrial ecoregion 1307.
Montebello Islands Marine Park, Lowendal Islands Nature Reserve, and Great Sandy Islands Nature Reserve, Pilbara region. The site of British nuclear tests in 1952 and 1956, these parks protect about 300 islands with mangroves, corals, tropical fish and seabirds. A whale migration path also passes by the islands. The Lowendal Islands are an Important Bird Area for crested tern and bridled tern. The Montebello Islands re an Important Bird Area for fairy tern, roseate tern, and sooty oystercatcher. Terrestrial ecoregion 1307 and marine ecoregion 144.
Muiron Islands Marine Management Area, Gascoyne region. Part of Ningaloo Coast World Heritage Site. The islands contain important turtle nesting areas. The limestone reef contains thousands of cardinalfish. Terrestrial ecoregion 1301 and marine ecoregion 144.
Murchison Radioastronomy Observatory (MRO), Mid West region. Home of the Australian Square Kilometer Array Pathfinder (ASKAP) project, this is a next-generation radio telescope. Terrestrial ecoregion 1310.
Ningaloo Marine Park, Gascoyne region. Part of Ningaloo Coast world Heritage Site. The 250-km long reef, located 100 m offshore is known for 220 species of coral and synchronized mass spawning (see overview section). Sharks, manta rays, humpback whale, turtles, whale sharks, and dugongs can be viewed. Marine ecoregions 145 and 210.
Shark Bay Marine Park, Gascoyne region. Part of Shark Bay World Heritage Site, this area is home to the world’s largest herds of dugong as well as loggerhead turtles, humpback whales, and 28 shark species. Stromatolites and the world’s largest seagrass beds are here. Marine ecoregion 210.
Shell Beach Conservation Park, Gascoyne region. Part of Shark Bay World Heritage Site. Billions of shells of Hamelin cockle create a beach one km wide and 10 m thick. Terrestrial ecoregion 1301 and marine ecoregion 210.
Sunday Island, Pilbara region. An Important Bird Area for roseate tern. Terrestrial ecoregion 1301 and marine ecoregion 144.
Tathra National Park, MidWest Region. The rolling sandplains are a wildflower viewing area. Terrestrial ecoregion 1209.
Thevenard Island, Pilbara region. Noted as a flatback turtle rookery. Terrestrial ecoregion 1301 and marine ecoregion 144.
Wallaby Saddle, Indian Ocean. This area offshore of Shark Bay is noted for aggregations of sperm whales.
Woodleigh, Gascoyne region. A 40-km wide impact crater, about 364 million years in age. Terestrial ecoregion 1301.
Wooramel Coast, Gascoyne region. Part of Shark Bay World Heritage Site. Mangroves line the coast of Shark Bay, while offshore are seagrass beds. Terrestrial ecoregion 1301 and marine ecoregion 210.
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