Eastern Mallee
Encyclopedia
Interim Biogeographic Regionalisation for Australia
The Interim Biogeographic Regionalisation for Australia is a biogeographic regionalisation of Australia developed by the Australian Government's Department of the Environment, Water, Heritage and the Arts...
(IBRA) subregion in southern Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
.
Geography
Eastern Mallee is roughly defined as the eastern half of the MalleeMallee (biogeographic region)
Mallee, also known as Roe Botanical District, is a biogeographic region in southern Western Australia. Located between the Esperance Plains, Avon Wheatbelt and Coolgardie regions, it has a low, gently undulating topography, a semi-arid mediterranean climate, and extensive Eucalyptus mallee...
biogeographic region. It has an area of around 46,000 square kilometres, and is very sparsely populated. The only towns occur along the road from Esperance
Esperance, Western Australia
Esperance is a large town in the Goldfields-Esperance region of Western Australia, located on the Southern Ocean coastline approximately east-southeast of the state capital, Perth. The shire of Esperance is home to 9,536 people as of the 2006 census, its major industries are tourism, agriculture,...
to Norseman
Norseman, Western Australia
Norseman is a town located in the Goldfields-Esperance region of Western Australia along the Coolgardie-Esperance Highway, east of Perth and above sea level. It is also the starting point of the Eyre Highway, and the last major town in Western Australia before the South Australian border to the...
. The largest and best known town is Salmon Gums
Salmon Gums, Western Australia
Salmon Gums is a small town in Western Australia located 106 km north of Esperance on the Coolgardie-Esperance Highway. The name is derived from a prominent stretch of Eucalyptus salmonophloia trees which formed a landmark in the town's early days. The town is part of the Shire of Esperance...
; others include Scaddan
Scaddan, Western Australia
Scaddan is a small town in Western Australia located east of Perth situated just off the Coolgardie-Esperance Highway between Norseman and Esperance in the Goldfields-Esperance region of Western Australia....
, Grass Patch
Grass Patch, Western Australia
Grass Patch is a small town in the Mallee region of Western Australia, located 79 km north of Esperance on the Coolgardie-Esperance Highway. The town was named after a nearby farm of the same name that had been settled around 1896 and was renowned for bountiful crops and good grass...
, Red Lake and Dowak, Western Australia.
Watercourses in the area include Young River
Young River (Western Australia)
The Young River is a river in Western Australia that rises south of the Frank Hann National Park then flows in a south easterly direction for a distance of before flowing into Stokes Inlet which discharges into the Southern Ocean....
, Lort River
Lort River
Lort River is a river located in the Goldfields-Esperance region and the Eastern Mallee sub-region of Western Australia.The headwaters of the Lort River begin in the Peak Charles National Park and its surrounding vacant Crown land...
, Oldfield River
Oldfield River
The Oldfield River is an ephemeral river in the Goldfields-Esperance region of Western Australia that rises inland from the South Coast at the edge of the Yilgarn plateau...
and Jerdacuttup River
Jerdacuttup River
Jerdacuttup River is a river located in the Goldfields-Esperance region of Western Australia.The water in the river is naturally saline.The river rises on the edge of the Yilgarn Plateau north of Ravensthorpe below Mounth Short and drains on the Eastern Side of the Ravensthorpe Range before flowing...
. Drainage is occluded, however, and the area has numerous salt pans.
Geology
Situated on the south-eastern edge of the Yilgarn CratonYilgarn craton
The Yilgarn Craton is a large craton which constitutes the bulk of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts...
, Eastern Mallee has a gently undulating landscape. It has a variety of surface types, including calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
s and loam
Loam
Loam is soil composed of sand, silt, and clay in relatively even concentration . Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils...
s containing kankar
Kankar
Kankar is a sedimentological term derived from Hindi occasionally applied in India and the United States to detrital or residual rolled, often nodular calcium carbonate formed in soils of semi-arid regions....
; outcrops of metamorphosed
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
; white and yellow sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
; and loamy pan fields. Gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
dune
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
s also occur in the area.
Climate
Western Mallee is semi-arid, with a warm, dry, Mediterranean climateMediterranean climate
A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...
, and a winter rainfall of 300 and 500 millimetres (12–19 in).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean daily maximum temperature | 30.5°C 86.9°F |
29.5°C 85.1°F |
27.2°C 81.0°F |
23.5°C 74.3°F |
19.6°C 67.3°F |
16.8°C 62.2°F |
16.0°C 60.8°F |
17.2°C 63.0°F |
20.4°C 68.7°F |
23.2°C 73.8°F |
26.1°C 79.0°F |
28.9°C 84.0°F |
23.2°C 73.8°F |
|
| Mean daily minimum temperature | 14.0°C 57.2°F |
14.2°C 57.6°F |
12.7°C 54.9°F |
10.0°C 50.0°F |
7.2°C 45.0°F |
5.6°C 42.1°F |
4.6°C 40.3°F |
4.7°C 40.5°F |
5.8°C 42.4°F |
7.5°C 45.5°F |
10.1°C 50.2°F |
12.3°C 54.1°F |
9.0°C 48.2°F |
|
| Mean total rainfall | 19.3 mm 0.7 in |
23.4 mm 0.9 in |
23.1 mm 0.9 in |
26.0 mm 1.0 in |
35.1 mm 1.4 in |
40.9 mm 1.6 in |
36.7 mm 1.4 in |
33.9 mm 1.3 in |
31.5 mm 1.2 in |
26.8 mm 1.0 in |
25.8 mm 1.0 in |
19.3 mm 0.7 in |
341.9 mm 13.2 in |
|
| Mean number of rain days | 3.9 | 4.1 | 4.9 | 7.1 | 9.4 | 10.8 | 11.9 | 11.5 | 9.7 | 7.7 | 5.7 | 4.2 | 90.9 | |
| Source: Bureau of Meteorology | ||||||||||||||
Vegetation
Mallee Woodlands and Shrublands
Mallee Woodlands and Shrublands is a Major Vegetation Group which occurs in semi-arid areas of southern Australia. The vegetation is dominated by mallee eucalypts which are rarely over 6 metres high...
communities consisting primarily of Eucalyptus
Eucalyptus
Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...
species. Clay soils support patches of Eucalyptus 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...
in addition to mallee, and calcareous clay areas are vegetated by communities of mallee with Melaleuca pauperiflora (Boree). Myrtaceous
Myrtaceae
The Myrtaceae or Myrtle family are a family of dicotyledon plants, placed within the order Myrtales. Myrtle, clove, guava, feijoa, allspice, and eucalyptus belong here. All species are woody, with essential oils, and flower parts in multiples of four or five...
and proteaceous
Proteaceae
Proteaceae is a family of flowering plants distributed in the Southern Hemisphere. The family comprises about 80 genera with about 1600 species. Together with the Platanaceae and Nelumbonaceae they make up the order Proteales. Well known genera include Protea, Banksia, Embothrium, Grevillea,...
scrub-heath occurs in sandstone areas, and salt affected areas grow Tecticornia (Samphire).
There are also a number of vegetation communities of lesser extent, including some that are considered endangered or at risk. These include 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:...
thicket
Thicket
A thicket is a very dense stand of trees or tall shrubs, often dominated by only one or a few species, to the exclusion of all others. They may be formed by species that shed large amounts of highly viable seeds that are able to germinate in the shelter of the maternal plants.In some conditions the...
communities of the Russell Range, and a vulnerable ecological community of herb and bunch grasslands that occurs on gypsum dunes along the margins of salt lakes. Granite outcrops
Granite outcrops of Western Australia
Granite outcrops of Western Australia are inselbergs and monoliths made from granite that are found across much of Western Australia. Rising abruptly from the surrounding landscape they create a variety of microhabitats for plants, and provide seasonal resources and refuge for a range of animals....
also have their own characteristic vegetation.
Flora and fauna
Information on Eastern Mallee's flora and fauna is scarce, as the area has not had a thorough biodiversity survey. What information is available has been gathered in the context of conservation assessment:The subregion contains many endemic plant species in the Eucalyptus
Eucalyptus
Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...
and Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
genera. It contains numerous rare, endangered and priority flora. Declared rare flora include Adenanthos eyrei
Adenanthos eyrei
Adenanthos eyrei is a species of shrub in the family Proteaceae. Restricted to a single cliff-top dune system on the remote south coast of Western Australia, it is listed as rare and endangered. It was discovered by E...
(Toolinna Adenanthos), Anigozanthos bicolor subsp. minor, Conostylis lepidospermoides (Sedge Conostylis), Drummondita longifolia, Eremophila denticulata subsp. denticulata (Toothed Eremophila), Eremophila lactea
Eremophila lactea
Eremophila lactea is a crititically endangered plant species which is indigenous to Western Australia.-Description:...
, Eucalyptus merrickiae, Leucopogon marginatus
Leucopogon marginatus
Leucopogon marginatus is a shrub of the heath family native to Western Australia. It was first described by W. Fitzgerald in 1904....
, Myoporum turbinatum and Ricinocarpos trichophorus.
It also supports a number of rare or endangered fauna, including the mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s Western Quoll (Dasyurus geoffroii) and Dibbler
Dibbler
Dibbler is the common name for Parantechinus apicalis, an endangered species of marsupial. It is an inhabitant of the southwest mainland of Western Australia and some offshore islands. It is a member of the Dasyuromorphia order, and the only member of the genus, Parantechinus...
(Parantechinus apicalis); the bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s Short-billed Black-Cockatoo
Short-billed Black-Cockatoo
The Short-billed Black Cockatoo or Carnaby's Black Cockatoo Calyptorhynchus latirostris is a cockatoo endemic to south-western Australia. Also known as the Large Black Cockatoo, or simply Carnaby's Cockatoo, it is black with white tail feathers and white cheek patches...
(Calyptorhynchus latirostris), Slender-billed Thornbill
Slender-billed Thornbill
The Slender-billed Thornbill is a small bird native to Australia. It includes three separate sub-species:* A. i. hedleyi* A. i. iredalei* A. i. rosinae...
(Acanthiza iredalei iredalei), Malleefowl
Malleefowl
The Malleefowl is a stocky ground-dwelling Australian bird about the size of a domestic chicken...
(Leipoa ocellata), Western Whipbird
Western Whipbird
The Western Whipbird is a passerine bird found in several scattered populations across southern Australia. It is predominantly olive green in colour....
(Psophodes nigrogularis), Crested Shrike-tit
Crested Shrike-tit
The Crested Shrike-tit is a bird endemic to Australia where it inhabits open eucalypt forest and woodland.-Taxonomy and distribution:...
(Falcunculus frontatus) and Hooded Plover
Hooded Plover
The Hooded Dotterel or Hooded Plover is a species of bird in the Charadriidae family. It is endemic to southern Australia and Tasmania. There are two recognized subspecies, both of which are classifed as Endangered....
(Charadrius rubricollis); and the Carpet Python
Carpet python
Morelia spilota is a large snake of the Pythonidae family found in Australia, Indonesia and New Guinea. There are 6 subspecies listed by ITIS, commonly referred to as Carpet and Diamond pythons.-Description:...
(Morelia spilota). Coastal areas are also visited by the Shy Albatross (Thalassarche cauta), the Australian Sea Lion
Australian Sea Lion
The Australian Sea Lion , also known as the Australian Sea-lion or Australian Sealion, is a species of sea lion that breeds only on the south and west coasts of Australia...
(Neophoca cinerea) and the Southern Right Whale (Eubalaena australis).
Land use
Around a quarter of Eastern Mallee falls within what the Department of Agriculture and Food terms the "Intensive Land-use Zone" (ILZ), the area of Western Australia that has been largely cleared and developed for intensive agriculture such as cropping and livestock production. The remaining three quarters of the subregion falls within the "Extensive Land-use Zone" (ELZ), where the native vegetation has not been cleared but may have been degraded by the grazing of introduced animals and/or changes to the fire regime. In total, around 70% of Eastern Mallee retains its native vegetation.Somewhat less than 15% of the subregion is held within nature reserve
Nature reserve
A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...
s, covering about 34% of the remaining native vegetation. Prominent nature reserves include Frank Hann National Park
Frank Hann National Park
Frank Hann National Park is a national park in Western Australia , located east-southeast of the capital, Perth in the Shire of Lake Grace. It was named for Frank Hann, an early explorer of the district...
, Peak Charles National Park
Peak Charles National Park
Peak Charles National Park is a national park in Western Australia , east of Perth and north west of Esperance.The park is named for one of the main features, Peak Charles, which is an ancient granite peak with an elevation of...
and Cape Arid National Park
Cape Arid National Park
Cape Arid National Park is a national park in Western Australia , south east of Perth. The park is situated east of Esperance and lies on shore from the eastern end of the Recherche Archipelago...
. There is also substantial mining in the area, with large areas covered by mines, mining tenements or exploration leases. There is also a small amount of gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
mining in the area, and some plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
forestry
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
.
Little is done to manage the subregion for conservation purposes, as most reserves are relatively undisturbed giving it a low management priority. Rising salinity
Salinity in Australia
Soil salinity and dryland salinity are two problems degrading the environment of Australia. Salinity is a concern in most states, but especially in the south-west of Western Australia....
is a threat in cleared areas, and this is completely unmanaged. The threat of bushfire is managed by the maintenance of firebreaks and fire access tracks. There is no management of feral rabbits and foxes, and incursions of agricultural weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
s.
The subregion was given a Continental Stress Class
Continental Stress Class
Continental Stress Class is a method of describing the landscape health of biogeographic regions in Australia. There are six Continental Stress Classes with Class 1 containing the most stressed regions and Class 6 the least stressed and therefore most healthy...
of 4 when measured against the criteria, but the authors of that assessment stated that it should more properly be rated at 3, because of the threat of salinity, and because clearance of western parts has resulted in a biased reserve system.
Biogeography
Eastern Mallee was introduced in IBRA Version 6.1. Its region code is MAL1. It is one of two subregions of the MalleeMallee (biogeographic region)
Mallee, also known as Roe Botanical District, is a biogeographic region in southern Western Australia. Located between the Esperance Plains, Avon Wheatbelt and Coolgardie regions, it has a low, gently undulating topography, a semi-arid mediterranean climate, and extensive Eucalyptus mallee...
region, the other being Western Mallee
Western Mallee
Western Mallee is an Interim Biogeographic Regionalisation for Australia subregion in southern Western Australia. It is a sparsely populated subregion with an area of about 47,000 square kilometres, roughly centred on the town of Newdegate...
. The Mallee, Avon Wheatbelt
Avon Wheatbelt
Avon Wheatbelt is an Interim Biogeographic Regionalisation for Australia region in Western Australia and part of the larger Southwest Australia savanna ecoregion.-Further reading:...
and Geraldton Sandplains
Geraldton Sandplains
Geraldton Sandplains is an Interim Biogeographic Regionalisation for Australia region in Western Australia and part of the larger Southwest Australia savanna ecoregion.It has two sub regions: -* Geraldton Hills sub region* Lesuer sub region...
regions together comprise Hopper
Stephen Hopper
Stephen Donald Hopper is a Western Australian botanist, specialising in conservation biology and vascular plants. He has written eight books, and has over 200 publications to his name. He was Director of Kings Park in Perth for seven years, and CEO of the Botanic Gardens and Parks Authority for five...
's Transitional Rainfall Zone
Transitional Rainfall Zone
The Transitional Rainfall Zone is one of three biogeographic zones into which south west Western Australia is divided, the others being the High Rainfall Zone and the Low Rainfall Zone...
of Beard
John Stanley Beard
John Stanley Beard was a British-born forester and ecologist who resided in Australia. While working with the Forestry Division in Trinidad and Tobago during the 1940s, Beard developed a system of forest classification for Tropical America and described the forests of Trinidad, Tobago, and the...
's South West Botanical Province.
Under the World Wide Fund for Nature
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...
's regionalisation of the world's terrestrial surface into "ecoregions", the Western Mallee subregion falls within the Esperance Mallee
Esperance mallee
Esperance Mallee is a World Wide Fund for Nature ecoregion on the south coast of Western Australia, a coastal strip where the predominant vegetation consists of short eucalyptus trees and shrubs.-Location and description:...
ecoregion, one of 6 ecoregions comprising the Southwest Australia
Southwest Australia
Southwest Australia is a biodiversity hotspot that includes the Mediterranean forests, woodlands, and scrub ecoregions of Western Australia. The region has a wet-winter, dry-summer Mediterranean climate, one of five such regions in the world...
ecozone.
Further reading
- Thackway, R and I D Cresswell (1995) An interim biogeographic regionalisation for Australia : a framework for setting priorities in the National Reserves System Cooperative Program Version 4.0 Canberra : Australian Nature Conservation Agency, Reserve Systems Unit, 1995. ISBN 0642213712