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The positive and negative conservation impacts of sheep grazing and other disturbances on the vascular plant species and vegetation of lowland subhumid Tasmania


  • J. B. Kirkpatrick,

  • Louise Gilfedder,

  • Kerry Bridle,

  • Andrew Zacharek

  • Professor Jamie Kirkpatrick is Head of School and Kerry Bridle is Research Fellow at the School of Geography and Environmental Studies, University of Tasmania (Private Bag 78, Hobart 7001, TAS, Australia. Tel. 61-3 6226 2460. Email:; Louise Gilfedder is Project Leader, Non-Forest Vegetation Project, Department of Primary Industries, Water and Environment (PO Box 44, Hobart 7001, TAS, Australia. Email: Andrew Zacharek is a Project Officer with the National Oceans Office (GPO Box 2139, Hobart 7000, TAS, Australia). This research emerged from a need to recognize potential for biodiversity conservation in an agricultural landscape.


Summary  An important conservation question for grazed areas of lowland subhumid Tasmania is ‘what effects do different, practical disturbance regimes have on native vegetation?’ An experiment designed to determine the single and interactive effects of fire and sheep grazing was established at four sites with distinct vegetation types. There were significant interactive effects of fire and sheep grazing on vegetation attributes at all sites. An analysis of published and new data indicated that there were several vascular plant species that appeared dependent on sheep grazing for their persistence in the present landscape, while there were others that were intolerant of this disturbance but required other types of disturbance, such as mowing. However, most native species appeared to survive in a wide variety of disturbance regimes short of ploughing and fertilization. The implications of these results are that a variety of disturbance regimes is necessary to maintain biological diversity in this environment, and that the naturalness of the regime is not necessarily relevant to its use for conservation.