Biodiversity and water point closure: is the grazing piosphere a persistent effect?
David B. Croft, Rebecca Montague-Drake, Matthew Dowle, 2007. "Biodiversity and water point closure: is the grazing piosphere a persistent effect?", Animals of Arid Australia: Out on their own?, Chris Dickman, Daniel Lunney, Shelley Burgin
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Occupation of the arid rangelands for pastoralism in Australia saw the establishment of numerous artificial waterpoints (AWP) to stabilise surface water availability. This was necessary in a landscape with predominantly ephemeral water supplies that are dependent on unpredictable and low rainfalls. The result has been a homogenisation of the landscape for grazing by livestock, and sacrifice of the vegetation and soils around AWP through the formation of grazing piospheres. The reservation of some former pastoral properties to create national parks has led to water management policies to remove redundant AWP, with the goal to reduce the extent of the piospheres and purported unnaturally high populations of kangaroos of various species that have grown around these perennial waters. Some recognition has been given to retention of AWP as a focus of wildlife observation to enhance the visitor experience. The latter motive is dominant in public lands in southern Africa and the arid parts of the USA where AWP have been added to support and sustain wildlife in arid or seasonally arid landscapes, rather than removed. We report a study of AWP in the stony downs and Strezlecki dunefield landsystems of Sturt National Park in the arid north-western corner of New South Wales. We found that the signature of the past 100 years of grazing by livestock remains regardless of whether AWP are retained or closed. We found no evidence of water-focussed grazing by Red Kangaroos but rather, like native mammalian herbivores elsewhere in arid rangelands, they are distributed according to shelter and forage availability. We found that the fauna most likely to be affected by AWP closure were birds, a focus of much high-value and high-yield wildlife tourism. Small mammal and lizard faunas were unaffected by AWP closure and the remnant fauna is likely to be that most resistant to the former impacts of livestock grazing. We offer recommendations about water management policies in respect to the pastoral inheritance of AWP and the conversion of pastoral properties to national parks.