The Murray Darling Depression , also known as the Murray-Darling woodlands and mallee, is a biogeographic

Biogeography

Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 region and an ecoregion

Ecoregion

An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...

 in southeastern Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 consisting of a wooded plain through which flow two of Australia's biggest rivers, the Murray

Murray River

The Murray River is Australia's longest river. At in length, the Murray rises in the Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between New South Wales and Victoria as it...

 and the Darling

Darling River

The Darling River is the third longest river in Australia, measuring from its source in northern New South Wales to its confluence with the Murray River at Wentworth, New South Wales. Including its longest contiguous tributaries it is long, making it the longest river system in Australia.The...

.

Location and description

The plains have a dry Mediterranean climate

Mediterranean 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...

 with more rainfall (400mm per year) in the south than in the drier north (250mm). Fires are common in the hot dry summers.

Flora

The original vegetation of the basin was mallee

Mallee (habit)

Mallee is the growth habit of certain eucalypt species that grow with multiple stems springing from an underground lignotuber, usually to a height of no more than ten metres...

 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...

 woodlands with thicker Black Box (Eucalyptus largiflorens

Eucalyptus largiflorens

Eucalyptus largiflorens, or Black Box, is a species of Eucalyptus which is endemic to Australia. It is a tree grows up to 20 metres in height...

) and River Red Gum (Eucalyptus camaldulensis) woodland on riverbanks but most has been cleared for wheat farming and pasture. The flora of the plain need to be adapted to renew itself after the summer droughts and accompanying fires.

Fauna

Wildlife of the area includes large numbers of lizards, ants, and Honeyeater

Honeyeater

The honeyeaters are a large and diverse family of small to medium sized birds most common in Australia and New Guinea, but also found in New Zealand, the Pacific islands as far east as Samoa and Tonga, and the islands to the north and west of New Guinea known as Wallacea...

 birds (especially of the Lichenostomus

Lichenostomus

Lichenostomus is a relatively large genus of honeyeaters . Of the 20+ species, most are restricted to Australia, but there are also a few species in New Guinea.It contains the following species:...

 and Meliphaga

Meliphaga

Meliphaga is a genus of bird in the Meliphagidae family.It contains the following species:* White-lined Honeyeater * Kimberley Honeyeater * Scrub Honeyeater...

 genera). Lizards include species of Skink

Skink

Skinks are lizards belonging to the family Scincidae. Together with several other lizard families, including Lacertidae , they comprise the superfamily or infraorder Scincomorpha...

 (especially of Ctenotus

Ctenotus

Ctenotus is a genus of skinks . It belongs to a clade in the Sphenomorphus group which contains such genera as Anomalopus and the close relatives Eulamprus and Gnypetoscincus....

, Egernia

Egernia

Egernia is a genus of skinks that occurs in Australia. These skinks are ecologically diverse omnivores that inhabit a wide range of habitats...

, and Lerista

Lerista

Lerista is a diverse genus of skink endemic to Australia which is especially notable for the variation in the amount of limb reduction . The variation ranges from short-bodied forms with large legs bearing five toes, to elongate forms completely lacking legs. The body length of the lizards ranges...

 genera). Ants include species of Iridomyrmex

Iridomyrmex

Iridomyrmex is a genus of ants that belongs to the subfamily Dolichoderinae. There are 79 species and subspecies that belong to this genus and they range from India to China to Australia and New Caledonia.-Description:...

, Carpenter ant

Carpenter ant

Carpenter ants are large ants indigenous to many parts of the world. They prefer dead, damp wood in which to build nests. They do not eat it, however, unlike termites. Sometimes carpenter ants will hollow out sections of trees. The most likely species to be infesting a house in the United States...

s, and Melophorus. Endangered species include the Black-eared Miner

Black-eared Miner

The Black-eared Miner, Manorina melanotis, is an endangered honeyeater endemic to mallee woodland in south-eastern Australia. It is closely related to the much more widely distributed Yellow-throated Miner M. flavigula and the taxonomic status of the Black-eared Miner is the subject of some...

 bird (Manorina melanotis) and the Malleefowl

Malleefowl

The Malleefowl is a stocky ground-dwelling Australian bird about the size of a domestic chicken...

 (Leipoa ocellata).

Threats and preservation

Although much of the plain has been cleared this is now carefully controlled and areas of protected natural vegetation remain, especially in the large Ngarkat Conservation Park

Ngarkat Conservation Park

Ngarkat Conservation Park is situated in South Australia's south-eastern corner. It consists of Mallee vegetation on an area that was once a seabed. It is bordered by Scorpion Springs Conservation Park, Mount Shaugh Conservation Park and Mount Rescue Conservation Park, which constitutes the...

 - Big Desert Wilderness Park

Big Desert Wilderness Park

Big Desert Wilderness Park, on the western border of Victoria, Australia, is the oldest of Victoria's three wilderness parks. It is a protected area of 1,130 square kilometres, with no vehicular access, and no defined walking tracks...

 on the 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...

-Victoria

Victoria (Australia)

Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....

border. Threats to habitats today come from introduced weeds, over-salination of rivers as water is drawn off for irrigation, over-use of fire to remove dry shrubs and prevent forest fires and overgrazing by introduced goats and rabbits.