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2 - The environment of the Australian sheep rangelands
- Edited by Graeme Caughley, Neil Shepherd, Jeff Short
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- Book:
- Kangaroos
- Published online:
- 05 November 2011
- Print publication:
- 29 May 1987, pp 14-34
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Summary
Introduction
The sheep rangelands, a subset of the arid and semi-arid lands of Australia, form a broad semi-circular arc from northern Queensland, through New South Wales, South Australia and the southern two-thirds of Western Australia (Fig. 1.5). It covers approximately 1.7 million km2 or 22% of the area of Australia. Climate determines the outer margin of the zone in the southern half of the continent: being the amount and incidence of rain sufficient to cultivate crops, particularly wheat. In southern New South Wales, South Australia and Western Australia this approximates the 260–290 mm isohyet. In southern Queensland the sheep rangelands extend into country receiving nearly 600 mm of rain per annum. The inner margin, where the sheep pastoral zone abuts either cattle rangelands or desert, is at about the 150 mm isohyet in the south and the 300 mm isohyet in the north.
This chapter examines the climate, soils, vegetation and fauna of the sheep rangelands of Australia, focusing on Kinchega National Park and a neighbouring sheep station, Tandou. These are located near the town of Menindee (elevation 61m) at approximately 32 degrees S and 142 degrees E in western New South Wales on the floodplain of the Darling River. Almost all data in succeeding chapters were collected on Kinchega and Tandou. Both were formerly part of a much larger pastoral lease and have been grazed by sheep since 1860. In 1967 Kinchega was declared a national park under the control of the New South Wales National Parks and Wildlife Service.
3 - The effect of weather on soil moisture and plant growth in the arid zone
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- By Greg Wellard
- Edited by Graeme Caughley, Neil Shepherd, Jeff Short
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- Book:
- Kangaroos
- Published online:
- 05 November 2011
- Print publication:
- 29 May 1987, pp 35-49
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Summary
Introduction
Rainfall is the dominant factor controlling the growth of plants in arid lands throughout the world (Beatley, 1969; Ross, 1969, 1976; Noy-Meir, 1973; Ross & Lendon, 1973; Gutterman, 1981; Orr, 1981). Much of the variability of pasture biomass can be explained by rainfall (Noy-Meir, 1973; Chapter 4). Temperature also plays a role in the initiation and success of germination and the survival of seedlings (Beatley, 1967; Gates & Muirhead, 1967; Lendon & Ross, 1978). Hence, rain falling at different seasons in the arid zone stimulates the germination of different suites of plant species.
This chapter reports the effect of rainfall and temperature on changes in soil moisture, pasture biomass, pasture growth and species composition on the two major soil types of Kinchega National Park.
The study posed the following questions:
(1) What is the relationship between rainfall and soil moisture and how does it differ between the two major soil types within the Park?
(2) Can trends in soil moisture or a knowledge of rainfall and temperature be used to predict changes in pasture growth and biomass?
The study was conducted within two exclosures, one on each of the two major soil types within Kinchega National Park. A fence excluded mammalian herbivores. Hence, growth, dieback and trends in biomass are measured in the absence of grazing. There is considerable evidence that grazing affects the growth rate of plants, sometimes stimulating growth and sometimes depressing growth or killing the plant (Harper, 1977; McNaughton, 1979).