Investigator Group
Encyclopedia
The Investigator Group is an archipelago comprising three scattered island groups off the western coast of the Eyre Peninsula
, South Australia
. It is named after HMS Investigator, which was captained by Matthew Flinders
when he explored the area in 1802. It lies at the eastern end of the Great Australian Bight
in the Southern Ocean
. All the islands except Flinders Island, and a part of Pearson Island, are within the Investigator Group Conservation Park.
. It consists of Waldegrave (292 ha) and Little Waldegrave (32 ha) Islands. They have calcarenite
soils and were grazed by sheep until 1967. The vegetation is mainly regenerating pasture, with patches of native shrubland
dominated by Native Juniper
and Coast Daisy-bush
.
The second group lies 28 km offshore. It consists of Flinders Island, which at 36 km2 is the largest island in the Investigator Group, with Ward Island and Topgallant Island. Flinders is leasehold land used for grazing. It has sandy, calcarenite soils, is mainly vegetated with pasture grasses, and has some remnant patches of heathland and Melaleuca
woodland
. Ward Island, 16 km to the west of Flinders, is covered with shrubland and heathland. Topgallant Island, 6 km to the east of Flinders, is a small island with steep cliffs and some stunted shrubland.
The third and southernmost group consists of Pearson Island (213 ha), the Veteran Isles (14 ha) and Dorothee Island (56 ha). Pearson Island, the second largest of the whole Investigator Group, and containing its highest point at 231 m above sea level, is vegetated with shrub and heathland with patches of Casuarina
and Melaleuca woodland. The Veteran Isles support low shrubland dominated by Twiggy Daisy-bush
and Marsh Saltbush
. Lying 3 km south-south-west of the Veteran Isles is Dorothee Island, the most southerly of the Investigator Group.
as an Important Bird Area
(IBA) because they support over 1% of the world population of Cape Barren Geese
and a population of the vulnerable
Fairy Tern. The IBA probably also supports over 1% of the world populations of Black-faced Cormorant
s and Pacific Gull
s.
Other birds for which the IBA is significant include large numbers of breeding Short-tailed Shearwater
s and White-faced Storm-Petrel
s. Little Penguin
s breed on Waldegrave, Little Waldegrave, Pearson and Dorothee Islands. The biome
-restricted Rock Parrot
has been recorded from most islands in the group.
Eyre Peninsula
Eyre Peninsula is a triangular peninsula in South Australia. It is bounded on the east by Spencer Gulf, the west by the Great Australian Bight, and the north by the Gawler Ranges. It is named after explorer Edward John Eyre who explored some of it in 1839-1841. The coastline was first explored by...
, South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
. It is named after HMS Investigator, which was captained by Matthew Flinders
Matthew Flinders
Captain Matthew Flinders RN was one of the most successful navigators and cartographers of his age. In a career that spanned just over twenty years, he sailed with Captain William Bligh, circumnavigated Australia and encouraged the use of that name for the continent, which had previously been...
when he explored the area in 1802. It lies at the eastern end of the Great Australian Bight
Great Australian Bight
The Great Australian Bight is a large bight, or open bay, off the central and western portions of the southern coastline of mainland Australia.-Extent:...
in the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
. All the islands except Flinders Island, and a part of Pearson Island, are within the Investigator Group Conservation Park.
Description
The northernmost group lies 3 km offshore near the small town of EllistonElliston, South Australia
Elliston is a small coastal town in South Australia on the west coast of Eyre Peninsula 169 km northwest of Port Lincoln and 641 km west of Adelaide. The township is located on Waterloo Bay....
. It consists of Waldegrave (292 ha) and Little Waldegrave (32 ha) Islands. They have calcarenite
Calcarenite
thumb|250px|The [[Pietra di Bismantova]] in central [[Italy]] is an example of calcarenite formation.Calcarenite is a type of limestone that is composed predominately, more than 50 percent, of detrital sand-size , carbonate grains...
soils and were grazed by sheep until 1967. The vegetation is mainly regenerating pasture, with patches of native shrubland
Shrubland
Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...
dominated by Native Juniper
Myoporum insulare
Myoporum insulare is a shrub or small tree which occurs on dunes and coastal cliffs in Australia. Common names include Common Boobialla, Boobialla, Native Juniper and, in Western Australia, Blueberry Tree....
and Coast Daisy-bush
Olearia axillaris
Olearia axillaris is a shrub of the Asteraceae family, found in coastal areas of Australia. Commonly known as the Coastal Daisybush, it was one of the first edible plants to be discovered by Europeans.-Description:...
.
The second group lies 28 km offshore. It consists of Flinders Island, which at 36 km2 is the largest island in the Investigator Group, with Ward Island and Topgallant Island. Flinders is leasehold land used for grazing. It has sandy, calcarenite soils, is mainly vegetated with pasture grasses, and has some remnant patches of heathland and Melaleuca
Melaleuca
Melaleuca is a genus of plants in the myrtle family Myrtaceae known for its natural soothing and cleansing properties. There are well over 200 recognised species, most of which are endemic to Australia...
woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
. Ward Island, 16 km to the west of Flinders, is covered with shrubland and heathland. Topgallant Island, 6 km to the east of Flinders, is a small island with steep cliffs and some stunted shrubland.
The third and southernmost group consists of Pearson Island (213 ha), the Veteran Isles (14 ha) and Dorothee Island (56 ha). Pearson Island, the second largest of the whole Investigator Group, and containing its highest point at 231 m above sea level, is vegetated with shrub and heathland with patches of Casuarina
Casuarina
Casuarina is a genus of 17 species in the family Casuarinaceae, native to Australasia, southeast Asia, and islands of the western Pacific Ocean. It was once treated as the sole genus in the family, but has been split into three genera .They are evergreen shrubs and trees growing to 35 m tall...
and Melaleuca woodland. The Veteran Isles support low shrubland dominated by Twiggy Daisy-bush
Olearia ramulosa
Olearia ramulosa is a species of flowering plant in the family Asteraceae. It occurs in New South Wales, Victoria, and Tasmania....
and Marsh Saltbush
Atriplex paludosa
Atriplex paludosa, commonly known as Marsh Saltbush, is a species of saltbush endemic to Australia.-Description:It grows as an erect shrub up to a metre high...
. Lying 3 km south-south-west of the Veteran Isles is Dorothee Island, the most southerly of the Investigator Group.
Birds
The islands have been identified by BirdLife InternationalBirdLife International
BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...
as an Important Bird Area
Important Bird Area
An Important Bird Area is an area recognized as being globally important habitat for the conservation of bird populations. Currently there are about 10,000 IBAs worldwide. The program was developed and sites are identified by BirdLife International...
(IBA) because they support over 1% of the world population of Cape Barren Geese
Cape Barren Goose
The Cape Barren Goose is a large goose resident in southern Australia. The species is named for Cape Barren Island, where specimens were first sighted by European explorers.-Taxonomy:...
and a population of the vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
Fairy Tern. The IBA probably also supports over 1% of the world populations of Black-faced Cormorant
Black-faced Cormorant
The Black-faced Cormorant , also known as the Black-faced Shag, is a medium-sized member of the cormorant family. Upperparts, including facial skin and bill, are black, with white underparts. It is endemic to coastal regions of southern Australia.-Ecology:The Black-faced-Cormorant feeds largely on...
s and Pacific Gull
Pacific Gull
The Pacific Gull is a very large gull, native to the coasts of Australia. It is moderately common between Carnarvon in the west, and Sydney in the east, although it has become scarce in some parts of the south-east, as a result of competition from the Kelp Gull, which has "self-introduced" since...
s.
Other birds for which the IBA is significant include large numbers of breeding Short-tailed Shearwater
Short-tailed Shearwater
The Short-tailed Shearwater or Slender-billed Shearwater , also called Yolla or Moonbird, and commonly known as the muttonbird in Australia, is the most abundant seabird species in Australian waters, and is one of the few Australian native birds in which the chicks are commercially harvested...
s and White-faced Storm-Petrel
White-faced Storm-petrel
The White-faced Storm Petrel , also known as White-faced Petrel is a small seabird of the storm-petrel family. It is the only member of the monotypic genus Pelagodroma....
s. Little Penguin
Little Penguin
The Little Penguin is the smallest species of penguin. The penguin, which usually grows to an average of in height and in length , is found on the coastlines of southern Australia and New Zealand, with possible records from Chile.Apart from Little Penguins, they have several common names...
s breed on Waldegrave, Little Waldegrave, Pearson and Dorothee Islands. The biome
Biome
Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a...
-restricted Rock Parrot
Rock Parrot
The Rock Parrot , also known as the Rock Elegant, is a parrot which is endemic to coastal South Australia, southern Western Australia, and that continent's offshore islands, including Rottnest Island. It is a small, predominantly olive-green parrot...
has been recorded from most islands in the group.