Heron Island, Australia
From Wikipedia, the free encyclopedia
Heron Island (23°26'31"S, 151°54'50"E) is a coral cay located near the Tropic of Capricorn in the southern Great Barrier Reef, 72 km north-east of Gladstone, Queensland, Australia, and 539 km north of the state capital Brisbane. The island is situated on the leeward (western) side of Heron Reef, a fringing platform reef of significant biodiversity, supporting around 900 of the 1,500 fish species and 72% of the coral species found on the Great Barrier Reef.[1]
The island is about 800 metres (2,600 ft) long and 300 metres (980 ft) at its widest, giving an area of approximately 16 hectares (40 acres). The highest point, near the western tip, is 3.6 metres (12 ft) ASL. A dune ridge along the southern shore rises some 3 metres (10 ft) ASL, lower dunes on the northeastern side are only about one metre (3 ft) above the sea.[2]
Heron Island and an extrapolated version of the research station are the scene of much of the first part of Arthur C. Clarke's The Deep Range.
Contents |
[edit] History
Heron Island was discovered on 12 January 1843 by the corvette HMS Fly. The ship was surveying the eastern edge of the Great Barrier Reef together with the cutter Bramble. The expedition was commanded by Captain Francis Blackwood and the reason for the expedition was mainly to map out detailed plans for safe passages within the reef.
The island did not become inhabited until the early 20th century when a turtle cannery was established. The aim was to profit from the seasonal influx of green turtles, but the venture soon found it difficult to keep the business afloat. Other attempts at establishing fisheries were abandoned.
In 1932 Captain Christian Poulsen, engaged in bringing fishing parties to the reef, realised the potential of the island as a tourist attraction. In 1936 he bought the lease of the island for £290. On 11 September 1943 the entire island was declared a National Park.[3]
[edit] Land use
[edit] Heron Island Resort
Heron Island Resort, operated by Voyages, is located in the north-west corner of the island. The resort is a popular getaway for scuba diving and snorkeling and accommodates up to 200 guests and 100 staff.[4]
[edit] Heron Island Research Station
The University of Queensland Heron Island Research Station is situated in the island's south-west quarter. Established in the 1950s, the facility is one of the world's principal coral reef research stations, with a wide variety of research undertaken on coral reef ecology. Heron Island Research Station suffered a large fire on Friday, 30 March 2007, at 4 am:
"A small number of staff and researchers who were at the station were safely evacuated. There were no students on site and no one was injured. Damage was to the station's research laboratories, a computer lab, student accommodation and part of the staff accommodation. The cause of the fire is being determined by an official investigation team."[5]
Along with the students' accommodations and the teaching laboratory, the new research building was destroyed. It contained 9 research labs, the library, the darkroom, the computer room and some aquaria.[1]
Since the station uses custom research equipment, some of which was damaged or destroyed in the fire, it was expected that the station would be fully operational again only in early 2008. However, little data was lost and research activity could start anew on a limited basis in summer 2007.[6]
[edit] National Park
The eastern half of the island is protected and forms part of the Capricornia Cays National Park, with a permanent ranger's station onsite.
[edit] Harbour
There is a small man-made channel and wooden jetty on the western shore of the island, where the daily catamaran launch from Gladstone docks and supplies to the island are delivered. The rusted wreck of the HMCS Protector lies at the entrance to the channel, and was towed to there in 1945 to form a dive and snorkelling site.
[edit] Utilities
The island has no fresh water supply. A small desalination plant on the island uses reverse osmosis technology to supply water for human consumption. Similarly, two diesel generators (and some solar panels) supply electricity to the island.
[edit] Ecology
Heron Island has notably rich soil for a tropical coral cay, particularly in the dense southern forest. This is due to the presence of tens of thousands of Wedge-tailed Shearwaters (Puffinus pacificus) during breeding season. These birds disturb the humus as they dig their nesting burrows, and thus prevent the formation of Jemo soil, a phosphatic hardpan topped off by raw humus. The hardpan is formed by leaching of surface- or tree-nesting seabirds' guano in the absence of burrowing animals.[2]
[edit] Flora
A rich forests of Pisonia grandis dominate the centre and south of Heron Island. Towards the eastern and northwestern ends, the forest is readily accessible, but its heart is a dense tangle, interrupted only by a few trails.[2]
Some trees in the heart of the forest grow to 10-11 m, but most are just 6-8 m high. The understory is largely absent here, formed only by scattered Celtis paniculata, Ficus opposita and Pipturus argenteus with a height of 2-4 m; some Celtis also grow higher and emerge through the Pisonia canopy. Patches of shrubs - mainly Abutilon albescens[verification needed], with Wedelia biflora (probably var. canescens), and the introduced Wild Poinsettia (Euphorbia cyathophora) - are found here and there. Herbaceous plants are scarce here, mainly consisting of the grass Stenotaphrum micranthum. The more open forest is composed of much the same plants, but the Pisonia does not predominate as much. A few Pandanus tectorius screwpines are also found here, and the understory is far more prominent.[2]
North of the Pisonia forest, a band of open shrubland with some trees extends from the resort to the island's eastern tip. Abutilon, Scaevola sericea and Wedelia are the characteristic plants. The trees here are mainly Pandanus, but also Celtis, the she-oak Casuarina equisetifolia ssp. incana, Ficus, Bay Cedar (Suriana maritima) and Octopus Bush (Tournefortia argentea). Herbs - mainly the parasitic vine Cassytha filiformis as well as Euphorbia tannensis ssp. eremophila and grasses (mainly Pacific Island Thintail, Lepturus repens var. subulatus) are abundant.[2]
The eastern end is marked by a similar habitat, with mainly Casuarina, Scaevola and Tournefortia. This type of vegetation, with some Pandanus in between, extends along the southern and northern dune ridges. On the dune slopes, Boerhavia repens, Commicarpus chinensis var. chinensis (or Commicarpus australis?), the searocket Cakile edentula, yet another Euphorbia (probably Euphorbia sparrmanii), and Kuroiwa Grass (Thuarea involuta) are common.[2]
East of the resort in the northwestern part of Heron Island there is another type of forest, more open than the central wood. The main tree here is the manjack Cordia subcordata of which few are found elsewhere on Heron Island; Pisonia trees are present but not dominant. The Abutilon-Euphorbia cyathophora-Wedelia scrub grows thick here. Scaevola and Tournefortia as well as patches of the dropseed grass Sporobolus virginicus occur at this forest's edge.[2]
The sea turtle nesting area is further east, making up the central part of the northern shoreside. The animals' burrowing has prevented a proper forest from forming. Consequently, though the usual tree species are found in isolated individuals, the sand is overgrown with herbs and small shrubs, mainly Cakile, Cassytha, Euphorbia eremophila, Lepturus and Wedelia.[2]
Around the western end there is an abundance of plants introduced by the research and resort activity, some deliberately as ornamentals, others accidentally. Notable are Euphorbia cyathophora and Pseudognaphalium luteoalbum, as well as Papaya (Carica papaya), Coconut Palm (Cocos nucifera), Oleander (Nerium oleander) and Temple Tree (Plumeria rubra) which have been planted[verification needed].[2]
[edit] Fauna
The island's forest and surrounding dunes provide habitat for thousands of nesting seabirds, including the Wedge-tailed Shearwater (Puffinus pacificus) and the Southwestern Black Noddy (Anous minutus minutus), during the breeding season between October and April[2]. Over 70,000 White-capped Noddies nest on the island during this period.
All-year resident and breeding on Heron Island are:
- Northern Silver Gull (Larus novaehollandiae forsteri)
- Common Eastern Reef Egret (Egretta sacra sacra)
- Australian Buff-banded Rail (Gallirallus philippensis mellori)
- Common Bar-shouldered Dove (Geopelia humeralis humeralis)
- Australian Sacred Kingfisher (Todiramphus sanctus sanctus)
- Common Black-faced Cuckoo-shrike (Coracina novaehollandiae novaehollandiae)
- Grey-breasted Silvereye (Zosterops lateralis lateralis)
This is the namesake "heron" of Heron Island.
Though other herons may occasionally visit the island, the only member of the Ardeidae which is a breeding resident is the Eastern Reef Egret[7]. And even though the terms "heron" and "egret" are not scientific, the former is generally used to denote the large Ardea whereas the smaller Egretta species are usually called "egrets". Insofar, the only "true" heron that could ever be found on Heron Island is the White-necked Heron (Ardea pacifica), which is only seen every now and then as a rare vagrant.
At some time in the mid-20th century, a pair of White-bellied Sea-eagles (Haliaeetus leucogaster) nested on Heron Island. However, these birds either died or moved elsewhere, and the species today only occurs as a non-breeding visitor, albeit not too rarely.[8]
At least one species of rat, probably the widespread Polynesian Rat (Rattus exulans), is found on the island[2]. Though even these small rats are known to harm island birds, this is insignificant on islands so close to a continent; while the rats probably feed on eggs and nestlings, they do not threaten the breeding bird populations as a whole.
Heron Island is also a major nesting site for Green (Chelonia mydas) and Indopacific Loggerhead Sea Turtles (Caretta caretta gigas). The Indopacific Hawksbill Sea Turtle (Eretmochelys imbricata bissa) has been seen on the reef but apparently does not breed on the island[2]. Other marine life includes the inhabitants of the coral reef, and around early October, cetaceans (e.g. Humpback Whales, Megaptera novaeangliae) pass Heron Island on their migration to their summer quarters in subantarctic waters.
A notable and much-studied invertebrate of Heron Island is Cerithium moniliferum, a small marine snail. These animals will form large groups as the tide recedes. Feeding on beach rock at a specific height over the average low tide level, the snails slowly move about in their clusters, preserving the precious moisture that allows them to breathe overwater.[2]
[edit] References
- ^ a b University of Queensland Centre for Marine Studies: Island Research Station. Retrieved 2006-JUL-14.
- ^ a b c d e f g h i j k l m Fosberg et al. (1961)
- ^ Coleman (1988): p.5
- ^ Heron Island, Great Barrier Reef. Voyages Resort. Retrieved on 2008-06-09.
- ^ UQ News: Update on Heron Island Research Station fire. Version of 2007-MAR-30. Retrieved 2008-APR-06.
- ^ UQ News: Reef research weathers island fire. Version of 2007-APR-04. Retrieved 2008-APR-06.
- ^ AW (2006)
- ^ Fosberg et al. (1961), AW (2006)
- Australian Wildlife (AW) (2006): Birds of Heron Island Twitcher's List. PDF fulltext
- Coleman, N. (1988): Discover Heron Island
- Fosberg, F.R.; Thorne, R.F. & Moulton, J.M. (1961): Heron Island, Capricorn Group, Australia. Atoll Research Bulletin 82: 1-16. PDF fulltext
