There is a consensus amongst ecologists that the rangelands ecosystems are under stress and that a reduction in total grazing pressure is likely to achieve improved ecological outcomes (Grigg 1987; Lunney 1994; Fisher et al. 2003). The question is how? Support for the kangaroo industry amongst ecologists has become synonymous with support for a reduction in total grazing pressure and the environment. The idea that using kangaroos in sustainable harvests could benefit rangelands was suggested as early as 1967 (Australian Conservation Foundation 1967) and coined as "sheep replacement therapy for the rangelands" (Grigg 1987; 2002), which proposes that the increased value of kangaroo meat may cause farmers to destock some or all livestock in favour of kangaroos. The decreased grazing pressure and reduced impact to soils from the hard hoofed livestock would ultimately benefit the environment. Another environmental proposition is that the replacement of sheep and cattle on the rangelands by kangaroos would result in up to a 3% reduction of Australia’s green house gas emissions (Wilson and Edwards 2008).
In both cases the benefit to the environment is predicated on the sheep replacement therapy idea. However, managed kangaroo harvesting has not led to any deliberate actions by landholders to conserve either kangaroos or their habitat (Grigg 2002; Chapman 2003; Thomsen and Davies 2008; Baumber et al. 2009; Ampt and Baumber 2010). Efforts are still underway to find a working business model of harvesting kangaroos, such as shared tagging and cooperative farming models (Thomsen and Davies 2008; Cooney et al. 2009; Ampt and Baumber 2010), that will create increased value in kangaroos for farmers. At present shooters and meat processors derive the primary income benefit from harvesting (Chapman 2003; Thomsen and Davies 2008; Cooney et al. 2009).
A further complication is that the replacement concept is placed in the middle of a paradigm were kangaroos are considered both overly abundant pests that damage the environment and a resource. For replacement to occur kangaroos need to be appreciated as a high value resource. Conservative estimates of total sheep replacement indicate that it would take 170 million kangaroos to replace all sheep and cattle in the rangelands (this excludes areas of QLD, SA and all of WA) on a meat equivalent basis (Wilson and Edwards 2008). Are those numbers, or parts thereof, sustainable? Another way of visualising the potential outcomes of eating kangaroo meat is if every Australian ate one meal of kangaroo meat a weak conservative estimates of carcass yields indicate that around 130 million kangaroos would need to be on the landscape (for a sustainable yield harvest). The thirty year kangaroo population estimates are less than 30 million (Department of Environment Water Heritage and Climate Change 2009). At the very best, if kangaroos are valued, there is no ecological data to suggest that this is possible or even desirable to have them in such high numbers. If we accept that kangaroos are pests than surely these increases are undesirable.
A number of notable publications raise questions about the logical consistency behind the sheep replacement argument. Rainfall patterns, not harvesting, are the key drivers of kangaroo populations on a regional scale (MaCarthy 1996, Pople 2004) . Artificial watering holes do not seem to affect the density and distribution of kangaroos (Montague-Drake and Croft 2004; Fukuda et al. 2010). Kangaroos only require a fraction of the food and water that livestock do and therefore culling and harvesting have little impact on livestock productivity (Grigg 2002; Munn et al. 2008). It follows that competition occurs during drought (Edwards et al. 1996; McLeod 1996). Graziers, which are by and large in a marginal industry (Croft 2000; Grigg 2002), will consider their commercial options carefully. Questions arise as to why they would forego the income from both livestock and kangaroos if they don’t compete? Will kangaroo numbers increase if properties are destocked? Will that be beneficial? Will harvesting kangaroos provide a reliable income base for pastoralists? What will be the impact of increased market demand for kangaroo meat on kangaroo population persistence?
There are alternatives to sheep replacement for alleviating total grazing pressure. The kangaroo is iconic and rates high amongst recognised symbols worldwide. Ecotourism managed by graziers, following African models, can offer a high value wildlife experience. Carbon credits for reduced stocking rates and ecological restoration grants can also form part of the monetary based incentives for destocking. Modern low impact grazing management is also being trialled in some parts of Australia.
Ampt, P. and A. Baumber (2010). Building Cooperation and Collaboration in the Kangaroo Industry. Kingston, ACT, Future of Australia's Threatened Ecosystems Programme.
Ampt, P. and A. Baumber (2010). Building Cooperation and Collaboration in the Kangaroo Industry. Barton, ACT, Rural Indistries Research and Development Cooperation.
Australian Conservation Foundation (1967). Conservation of Kangaroos. Viewpoint Series No. 1. Canberra, Australia.
Baumber, A., R. Cooney, P. Ampt and K. Gepp (2009). "Kangaroos in the rangelands: opportunities for landholder collaboration." The Rangeland Journal 31: 161-167.
Chapman, M. (2003). "Kangaroos and feral goats as economic resources for graziers: some views from a Southwest Queensland." Rangeland Journal 2003: 20-36.
Cooney, R., A. Baumber, P. Ampt and G. Wilson (2009). "Sharing Skippy: how can landholders be involved in kangaroo production in Australia?" The Rangeland Journal 31: 283-292.
Croft, D. B. (2000). "Sustainable use of wildlife in western New South Wales: Possibilities and problems." Rangeland Journal 22(1): 88-104.
Department of Environment Water Heritage and Climate Change (2009, 06/01/09). "Kangaroo and wallaby harvesting statistics." Retrieved 21/01/2009, from http://www.environment.gov.au/biodiversity/trade-use/wild-harvest/kangaroo/stats.html.
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