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Woodlands on farms in southern New South Wales: A longer-term assessment of vegetation changes after fencing

Authors

  • Peter G. Spooner,

  • Sue V. Briggs


  • Peter Spooner is a vegetation ecologist based at the School of Environmental Sciences, Charles Sturt University (GPO Box 789, Albury, NSW 2640, Australia; Tel. +61 2 6051 9620; Email: pspooner@csu.edu.au). Sue Briggs is a principal research scientist with the New South Wales Department of Environment and Climate Change. She is based at CSIRO Sustainable Ecosystems (GPO Box 284, Canberra, ACT 2601, Australia). This research was undertaken as part of the Better Knowledge Better Bush Project funded by the New South Wales Environmental Trust to increase knowledge for better management of native vegetation.

Abstract

Summary  Fencing incentive programmes have been widely used throughout Australia to assist landholders to fence remnant woodland vegetation, to control grazing and improve native vegetation condition. This study investigated vegetation and soil condition in remnant woodlands fenced for 7–9 years in the Murray catchment area in southern New South Wales. Surveys were undertaken at 42 sites, where vegetation condition was assessed in paired fenced and unfenced sites. Semi-structured interviews were also conducted with landholders to gather management information. Woodlands surveyed were Yellow Box/Blakely's Red Gum (Eucalyptus melliodora/E. blakelyi, 15 sites), Grey Box (E. microcarpa, 13 sites) and White Cypress Pine (Callitris glaucophylla, 14 sites).

Fencing resulted in a range of responses which were highly variable between sites and vegetation types. In general, fenced sites had greater tree regeneration, cover of native perennial grasses, less cover of exotic annual grasses and weeds, and less soil compaction than unfenced sites. However, there was greater tree recruitment in remnants to the west of the study area, and tree recruitment was positively correlated with time since fencing. Within sites, tree recruitment tended to occur in more open areas with a good cover of native perennial grasses, as compared to sites with a dense tree canopy, or dominated by exotic annuals grasses or weeds. Forty-eight per cent of fenced sites had no tree regeneration. There was a significant decline in native perennial grasses, and increase of several unpalatable weeds in many fenced areas, suggesting certain ecological barriers may be preventing further recovery. However, drought conditions and associated grazing are the most likely cause of this trend. A range of grazing strategies was implemented in fenced sites which require further research as a conservation management tool. Continued long-term monitoring is essential to detect key threats to endangered woodland remnants.

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