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Alpine grazing: does it reduce blazing?

Monday, 2 December 2013  | 

The Victorian Mountain Cattlemen’s Association has called for the re-introduction of cattle grazing in the Victorian Alpine National Park to reduce fire risk, based on their view that ‘alpine grazing reduces blazing’. However, a substantial body of peer-reviewed scientific evidence indicates that alpine grazing does not reduce fire risk.

Detailed studies of the 2003 and 2007 fires in the Victorian Alpine National Park showed that cattle grazing had little or no effect on occurrence and/or severity of fire in the alpine vegetation above treeline, and in the surrounding subalpine woodland and montane forest. Flammability depended largely on vegetation type. For example, the 2003 fires on the Bogong High Plains burnt 87% of closed heathland and 59% of open heathland, but only 13% of grassland; grazing did not reduce the incidence of fire in any of these vegetation types.

Cattle graze selectively and this partly explains why grazing had little effect on the patterns of burning.  On the Bogong High Plains detailed studies have shown that cattle prefer to graze on the grasses and herbs of the more open vegetation types such as grassland and open heathland, and avoid eating the tall shrubs of the closed heathland. Long-term monitoring on the Bogong High Plains for over 50 years has shown that cattle grazing has not reduced the cover of tall shrubs that dominate the most flammable vegetation – closed heathland.

Victoria’s alpine vegetation is resilient to large fires and there is no apparent conservation imperative to mitigate the extent or severity of large fires. Livestock grazing, on the other hand, has well-documented negative impacts on the conservation values of Australia’s rare alpine and subalpine ecosystems. There is therefore no scientific basis to support the re-introduction of cattle grazing to reduce fire risk in Australian alpine and subalpine ecosystems.

Supporting Research

Gibson N., Kirkpatrick J.B. (1989) Effects of cessation of grazing on the grasslands and grassy woodlands of the central plateau, Tasmania. Australian Journal of Botany 37, 55–63.
To assess the variability of the impact of the removal of grazing pressure over an environmental (productivity) gradient (pp. 55).
Leonard, S., Kirkpatrick, J., Marsden Smedley, J. (2010) Variation in the effects of vertebrate grazing on fire potential between grassland structural types. Journal of Applied Ecology 47, 876–883.
To "examine the degree to which vertebrate grazing affects fire potential (i.e. the likelihood that given a source of ignition, a fire will sustain and spread) in native grasslands in Tasmania, Australia"' (pp. 877).
van Rees H. (1982) The diet of free-ranging cattle on the Bogong High Plains, Victoria. Australian Rangeland Journal 4, 29–33.
To determine the species composition of the diet of free-ranging cattle... to estimate the most important components of the diet… (and) to determine the digestibility and nitrogen content of plants regularly grazed by cattle (pp. 29).
Van Rees H., Holmes J.H.G. (1986) The Botanical Composition of the Diet of Free-Ranging Cattle on the Alpine Range in Australia. Journal of Range Management 39, 392–395.
To define quantitatively the diet of cattle in the 3 most common alpine vegetation communities, and to relate the composition of the diet to the availability of plant species in the field (pp. 392).
van Rees H., Hutson G.D. (1983) The behaviour of free-ranging cattle on an alpine range in Australia. Journal of Range Management 36, 1983.
To investigate the behaviour and movements of free-ranging cattle on an Australian Alpine Range.
Williams R.J., Wahren C.H.A., Bradstock R.A., Muller W.J. (2006) Does alpine grazing reduce blazing? A landscape test of a widely-held hypothesis. Austral Ecology 31, 925–936.
To evaluate, at a landscap-scale, the effect of livestock grazing on the extent and severity of the 2003 fires in treeless alpine landscapes.
Williamson G.J., Murphy B.P., Bowman D.M.J.S. (2013) Cattle grazing does not reduce fire severity in eucalypt forests and woodlands of the Australian Alps, in review.
Determine "whether fire severity in eucalypt forests and woodlands in the alpine bioregion is reduced in areas subject to cattle grazing."
Wahren C.H.A., Papst W.A., Williams R.J. (1994) Long-term vegetation change in relation to cattle grazing in subalpine grassland and heathland on the Bogong High Plains: an analysis of vegetation records from 1945 to 1994. Australian Journal of Botany 42, 607–639.
To assess the trends in, and impacts of cattle grazing on, both vegetation composition and ground cover in two major subalpine plant communities--grassland and open heathland--within the permanent plots established in the 1940s on the Bogong High Plains' (pp. 607-608)
Williams R.J., Ashton D.H. (1987) Effects of disturbance and grazing by cattle on the dynamics of heathland and grassland communities on the Bogong High Plains, Victoria. Australian Journal of Botany 35, 413–431.
To examine the factors affecting the establishment of shrubs within both heathland and grassland communities, and to assess the role which grazing by domestic livestock may have in this process (pp. 413).
Camac J.S., Williams R.J., Wahren C.H., Morris W.K., Morgan J.W. (2013) Post-fire regeneration in alpine heathland: Does fire severity matter? Austral Ecology 38, 199–207.
To "examine the effects of variation in fire severity on (alpine) plant diversity and vegetation composition, 5 years after the widespread (alpine) fires of 2003" (pp. 199).
Wahren C.H.A., Papst W.A., Williams R.J. (2001) Early post-fire regeneration in subalpine heathland and grassland in the Victorian Alpine National Park, south-eastern Australia. Austral Ecology 26, 670–679.
To "summarize the early post- fire changes in vegetation and ground cover conditions that have occurred in grassland and heathland on Holmes and Wellington Plains" (pp. 671).
Walsh N.G., McDougall K.L. (2004) Progress in the recovery of the flora of treeless subalpine vegetation in Kosciuszko National Park after the 2003 fires. Cunninghamia 8, 439–452.
To assess the mode and extent of regeneration of plants in treeless subalpine plant communities of Kosciuszko National Park that were burnt in the 2003 alpine fires
Williams R.J., Papst W.A., McDougall K.L., Mansergh I.M., Heinze D., Camac J.S., Nash M.A., Morgan J.W., Hoffmann A.A. (2014) Alpine ecosystems. In: Biodiversity and Environmental Change: Monitoring, Challenges and Direction. (Eds: Lindenmayer D, Burns E, Thurgate N, Lowe A) pp 169-214. CSIRO Publishing, Melbourne.
To summarise the nature of environmental change in Australian alpine environments, with particular reference to policy development and implications.
Williams R.J., Wahren C.H.A., Tolsma A.D., SaneckI G.M., Papst W.A., Myers B.A., McDougall K.L., Heinze D.A., Green K. (2008) Large fires in Australian alpine landscapes: their part in the historical fire regime and their impacts on alpine biodiversity. International Journal of Wildland Fire 17, 793–808.
To explore the ‘disaster–diversity’ hypotheses in the aftermath of the 2003 fires on Australian alpine landscapes (pp. 793). The hypothesis holds that "large arge fires such as the 2003 fires were unnatural, the result of decades of fire exclusion, and consequent fuel build-up, in the foothill, montane and subalpine forests, and a disaster for biodiversity in both the wooded and treeless landscapes" (pp. 794).