Who's planting what, where and why – and who's paying?: An analysis of farmland revegetation in the central wheatbelt of Western Australia
Introduction
Many regions of Australia have been extensively cleared of native vegetation to make way for agriculture. In the wheatbelt of Western Australia – a zone of 18 million hectares in the south west receiving 300–600 mm annual rainfall – only 10% of the native vegetation remains on average, with the figure being as low as 3% in many places (Beard and Sprenger, 1984). The replacement of native deep rooted woody perennials with annual crops on this scale has resulted in substantial hydrological change and the onset of secondary dryland salinity which affects as much as 10% of this zone now and could exceed 30% by 2050 (Ferdowsian et al., 1996, National, 2001). The revegetation of cleared agricultural lands with woody perennials has therefore been a significant aspect of land use change in Western Australia (WA) since the 1980s, with suggestions that anywhere from 30 to 80% of the landscape may need to be replanted (Bell et al., 1990, Schofield and Bari, 1991, Farrington and Salama, 1996, AGO-MDBC, 2001, George et al., 1999). In addition to salinity mitigation, tree planting on farms has also been promoted for the purposes of land conservation, timber production, wildlife conservation and biofuels (e.g. see Abel et al., 1997).
Various government and community schemes have promoted, and sometimes funded, the planting of trees (and other woody vegetation) on farms. Three important government programs have been the National Landcare Program of the Commonwealth Department of Agriculture, Forestry and Fisheries (ongoing since 1992), the National Heritage Trust of the Commonwealth government (ongoing since 1997), and the National Action Plan for Salinity and Water Quality of the Council of Australian Governments (ongoing since 2000), but other smaller schemes have also involved farmland revegetation. However, surprisingly little is known about the outcomes of these schemes or the extent and nature of the farmland revegetation that has been undertaken. Indeed the Australian National Audit Office was critical of the National Heritage Trust for its failure to link funded activities to outcomes (Australian, 1996, Australian, 2001). While volumes have been written to promote and guide the implementation of farmland revegetation (Greening Australia, 2007), very little work appears to have been done to document and understand what farmers and other rural landholders have actually achieved in this area. By taking a case study approach using the neighbouring Wallatin Creek and O’Brien Creek catchments from the central wheatbelt of Western Australia, this paper seeks to answer some basic questions about farmland revegetation such as how much has been planted, who has planted it, where in the landscape it is, what specifically has motivated plantings, and what is the balance between public and private funding of revegetation efforts?
Section snippets
Study area
The neighbouring Wallatin Creek and O’Brien Creek catchments occur in the low-medium rainfall zone of the Western Australian ‘wheatbelt’ (Fig. 1). The wheatbelt is a region of mixed cereal and livestock farms that is described in some detail by Anderson and Garlinge (2000). The study catchments occur approximately mid-way on both the N-S and E-W transects of the WA wheatbelt and while no catchment could be considered typical of the whole wheatbelt region, these catchments may be regarded in
Area of revegetation
To the end of 2005 a total area of 1 750 ha had been revegetated within the boundaries of the Wallatin and O’Brien Creek catchments in a total of 379 separate plantings (Fig. 1). This represents 4.6% of the land surface area of the catchments (total area 37 667 ha) and substantially augments the 3600 ha (9.4%) of remnant uncleared native vegetation.
All landholders in the catchments have undertaken some revegetation, but individuals differ as to the amount both in absolute and relative terms (Fig. 2
Discussion
The extent of revegetation activities in the Wallatin and O’Brien Creek catchments over the period 1980–2004 is remarkable. Unfortunately very few data are available that allow direct comparison of this effort with similar agricultural landscapes in Australia. Some comparisons can be made using a recent report of 5 regional study areas, including the Wallatin and O’Brien, which suggests that revegetation in the Wallatin and O’Brien catchments may be an order of magnitude greater than what is
Conclusions
Farmers in the Wallatin and O’Brien Creek Catchments have achieved unusually high rates of revegetation for a low-medium rainfall agricultural landscape in Australia, replanting 4.9% of their cleared farmland and increasing the cover of woody perennials in the catchments by almost 50%. This planting activity, which peaked in the mid-late 1990s but has now ceased, has mostly been funded by the farmers themselves. The revegetation has typically driven by a mixture of motives and to these farmers
Acknowledgements
The support and co-operation of the farmers of the Wallatin and O’Brien creek catchments is gratefully acknowledged. The assistance of CSIRO colleagues is also gratefully acknowledged, including the assistance of Dr Tom Measham, Blair Parsons, Justin Jonson and Trevor Parker in collecting and collating the data, and the assistance of Dr Michael O’Connor in accessing and compiling the unpublished data of Arnold and Weeldenburg.
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