Natural
- as an outstanding example representing the major stages in the earth's evolutionary history; and
- as an outstanding example representing significant ongoing geological processes.
Cultural
- bearing an exceptional testimony to a past civilisation.
The region contains a system of Pleistocene lakes, formed over the last two million years. Most are fringed on the eastern shore by a dune or lunette formed by the prevailing winds.
Today, the lake beds are flat plains vegetated by salt tolerant low bushes and grasses. About 10 per cent of the World Heritage area is gazetted as the Mungo National Park, which covers about two-thirds of Lake Mungo and includes the spectacular parts of the Walls of China lunette. The remaining area comprises pastoral leasehold properties.
There are five large, interconnected, dry lake basins and fourteen smaller basins varying from 600 to 35 000 hectares in area. The original source for the lakes was a creek flowing from the Eastern Highlands to the Murray River. When the Willandra Billabong Creek ceased to replenish the lakes, they dried in series from south to north over a period of several thousand years, each becoming progressively more saline.
The ancient shorelines are stratified into three major layers of sediments that were deposited at different stages in the lakes' history.
The earliest sediments are more than 50 000 years old and are orange-red in colour. Above are clays, clean quartz sand and soil that were deposited along the lakes' edges when the lakes were full of deep, relatively fresh water, between 50 000 and 19 000 years ago. The top layer is composed largely of wind-blown clay particles heaped up on the lunettes during periods of fluctuating water levels, before the lakes finally dried up.
Aborigines lived on the shores of the Willandra Lakes from 50 000 to 40 000 years and possibly up to 60 000 years ago. Excavations in 1968 uncovered a cremated female in the dunes of Lake Mungo. At 26 000 years old, this is believed to be the oldest cremation site in the world. In 1974, the ochred burial of a male Aborigine was found nearby.
The use of ochres for burial in Australia 30 000 years ago parallels their use in France at the same time. Radiocarbon dating established that these materials were some of the earliest evidence of modern humans in the world.
During the last Ice Age, when the lakes were full, the Mungo people camped along the lake shore taking advantage of a wide range of food, including freshwater mussels and yabbies, golden perch and Murray cod, large emus and a variety of marsupials, which probably included the now extinct super roos. They also exploited plant resources, particularly when the lakes began to dry and food was less abundant.
The human history of the region is not restricted just to an ancient episode. Evidence so far points to an extraordinary continuity of occupation over long periods of time. In the top layers of sediments there is abundant evidence of occupation over the last 10 000 years.
The vegetation in the region, sparse though it is, is typical of the semi-arid zone. It plays an important role in stabilising the landscape and hence maintaining its sediment strata and many species of native fauna.
On the dunes are found the small scrubby multi-stemmed mallee eucalypts with an understorey of herbs and grasses. Rose wood-belah woodland is common on the sand plains. In the lake beds, several species of salt bushes are able to thrive in the saline conditions.
The remains of a large number of animals have been found in Willandra. More than 55 species have been identified, 40 of which are no longer found in the region, and 11 are totally extinct.
Twenty-two species of mammals are currently recorded at Willandra, of which bats are the most diverse group. There are some 40 species of reptiles and amphibians.
The bird life of the Willandra region is similar to that in many other semi-arid areas of Australia. Parrots, cockatoos and finches are the most conspicuous of the 137 recorded species.
Policy coordination and funding are the responsibility of the joint State/Commonwealth Ministerial Council, with advice from a Community Management Council and a Technical and Scientific Advisory Committee. Day-to-day management is the responsibility of the NSW Department of Land and Water Conservation and the NSW National Parks and Wildlife Service.
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