Catastrophic drought-induced die-off of perennial chenopod shrubs in arid Australia following intensive cattle browsing |
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Authors: | John L. Read |
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Affiliation: | Department of Land Management, WMC Resources, Roxby Downs, SA 5725, Australia |
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Abstract: | Cover and survivorship of perennial chenopods, Atriplex vesicaria and Maireana astrotricha, declined markedly during a prolonged dry period at Roxby Downs in arid South Australia. Despite their resilience to browsing in favourable seasons, only 2% of the A. vesicaria shrubs browsed heavily by cattle survived the drought. M. astrotricha exhibited greater drought survivorship, although the post-drought cover retention in browsed shrubs was only half that of unbrowsed controls. Survivorship was highest for unbrowsed chenopods growing in moisture-enhanced run-on or dune-base environments. Maintenance of these patchy areas with reduced water-stress is hence important for the persistence of browsed chenopod shrublands. Light browsing by either European Rabbits (Oryctolagus cuniculus) or Greater Stick-nest Rats (Leporillus conditor) had no measurable impact upon chenopod survivorship. |
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Keywords: | Chenopod Atriplex Maireana Cattle browsing Water stress Plant death Survivorship Drought |
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