This post has been extracted from the author’s submission to Australia’s parliamentary inquiry into the nation’s faunal extinction crisis. Supplementary video and radio links have been added to this version.
Depending on the definition used, the rangelands of Australia (often referred to as the Outback) cover between 73 and 81 per cent of the continent. [1] [2]
Many mammals in the rangelands have become extinct during the past century and many species are now threatened with extinction, including the bilby, night parrot, mala, sandhill dunnart and tjakura (great desert skink). [3]
In their 2014 report “The Modern Outback”, The Pew Charitable Trusts highlighted some of the deleterious impacts of pastoralism on the rangelands, including: introduction of feral species such as donkeys, horses, cattle, buffalo, goats and camels; introduction of invasive pasture grasses; land clearing (with habitat loss and fragmentation); degradation of natural water sources; proliferation of artificial water sources; dingo baiting; and manipulation of fire regimes. [4]
They have said:
“Indeed, in some ways, the impacts of pastoralism on biodiversity and other environmental values are almost pervasive across the Outback landscapes . . .”
Of the factors listed, this article focuses on the introduction of invasive pasture grasses and manipulation of fire regimes.
Invasive pasture grasses
Around a quarter of more than 600 exotic plant species established in pastoral areas of the rangelands are now considered to be a threat to the natural environment. [5] Five invasive pasture grasses (gamba grass, para grass, olive hymenachne, perennial mission grass and annual mission grass) have been listed under national environmental law as a key threatening process to Australian biodiversity.
Gamba grass was introduced to the Northern Territory from Africa in 1931 for testing as a pasture grass. It was introduced to Queensland in 1942. Large-scale planting did not begin until around 1983. [6]
The grass can grow more than four metres high, is closely spaced and vigorous.
It is invasive, competes with native grasses and greatly increases the frequency and intensity of wildfires. Its presence has led to ecosystem degradation, habitat loss and species decline. [7]
Fires in areas with gamba grass typically burn from five to twenty times more intensely than in comparable areas without it. Whereas normal dry season fires have few or no impacts on trees, fires fuelled by gamba grass kill them. [8]
Figure 1: A site heavily invaded with gamba grass with a decline in overstory trees due to high intensity fires
Figure 2: Gamba grass fire on Camp Creek station in October 2012
The fuel load with gamba is up to 30 tonnes per hectare, compared to around 6 tonnes with native grasses. [9]
The loss of fauna from tree deaths is extensive, as demonstrated by the fact that tree hollows are essential for 18 per cent of birds, 40 per cent of mammals, 20 per cent of reptiles and 13 per cent of frogs. [10]
Its rate of spread is among the highest of any invasive plant in the world, and modelling has indicated that invasions have the potential to turn the diverse woodlands of northern Australia into vast monocultures. [11] [12]
Referring to the level of infestation, Dr Barry Traill of The Pew Charitable Trusts and co-author of “The Modern Outback” has said: [13]
“That in itself is terrible, it’s a very large area in the top end of the Territory, but the big concern, the big threat, the huge worry is that it could spread right throughout the tropical savannas of the north. This is, people don’t generally realise, we have the largest remaining tropical savanna on the planet, the northern Outback, and it would be terrible to lose that to this invader.”
Gamba has been banned in Western Australia, and its use is restricted by legislation in the Northern Territory and Queensland. [14]
The livestock sector has resisted a call by two hundred scientists for gamba to be banned from sale in Queensland and the Northern Territory. The cattle president of Queensland’s peak farm lobby group, AgForce, Greg Brown has said: [15]
“It was legitimately introduced and as far as we’re concerned it . . . should remain as one of a suite of pasture species that is available to the pasture industry.”
Referring to the cattle sector, researcher Denise Goodfellow has said: [16]
“. . . the importance of Gamba to the cattle industry has meant that various stations have been allowed to keep grazing cattle on the weed to the dismay of indigenous rangers who find themselves fighting a losing battle trying to control the weed and fight fires, and those of us who care about our wildlife.”
The pastoralists’ tragic legacy is well described by Timothy Neale of Deakin University: [17]
“The disaster of Gamba’s slow expansion has the potential to create an enduring set of transitions. A transition to an ecology in which the one excludes the many. A transition from an ecology assembled through millennia of use by indigenous peoples to one assembled by the fallout of unsustainable settler pastoralism. A transition from an ecology in which fire is a source of common renewal and flourishing (humans included) to one in which it is a common mortal threat.”
Barry Traill believes the only efficacious way of dealing with gamba is to apply glyphosate, which is commonly marketed under Monsanto’s Roundup label. [18] It seems ironic that anti-glyphosate campaigner, author and sheep farmer Charles Massy is a member of the sector responsible for gamba’s use in Australia. [19]
Buffel grass is another African grass that forms dense monocultures, changes fire regimes, and displaces native plants, with particular concern expressed by the government of South Australia. [20]
They have stated: [21]
“The potential value of buffel grass for livestock production is offset by its serious conservation and social impacts. It has been identified as a ‘transformer weed’ of the Australian rangelands (Bastin et al. 2008) due to its ability to transform the basic attributes of habitats. Modelling suggests buffel grass could establish in over 60% of mainland Australia (Lawson et al. 1994).”
Other fire regimes
Even without the infestation of gamba and other highly flammable exotic pasture grasses, changing fire regimes represent a critical problem for the rangelands and the native plants and animals inhabiting it.
Barry Traill has commented as follows on the negative impact of falling Aboriginal populations in remote areas: [22]
“Drier areas were burnt in particular ways by Aboriginal people. The usual pattern was to have smaller spot fires in different seasons to create a patchwork of vegetation of various ages. This mosaic approach provides the right habitat mix for different animals, particularly some mammals.”
He pointed out that without people to manage the burning, most outback fires are larger and fiercer than they were previously. For example, in the western desert country of the Martu people, the average area of a single fire has increased from 64 hectares to 52,000 hectares.
“The Modern Outback” publication referred to earlier highlighted the extensive benefits that have been derived through the introduction of indigenous ranger groups and the declaration of indigenous protected areas (IPAs). At the time of publishing, there were 67 IPAs covering more than 540,000 square kilometres, which is more than twice the size of the state of Victoria. There were also more than 750 indigenous rangers managing and safeguarding the land.
The Pew Charitable Trusts have campaigned for state governments to permit non-grazing related activities on pastoral leases, thereby “making a diversity of options available for pastoral lease lands and ensuring good governance with a focus on sustainable management, population support and economic viability”. [23]
Fire regimes in the rangelands have also been highlighted by Gerard Wedderburn-Bisshop, a former principal scientist with the Queensland Department of Environment and Resources Management Remote Sensing Centre. [24]
He added context to the extent of burning for livestock grazing in Australia’s tropical savanna (with significant impacts on native animal animals and their habitat), by noting that the 2009 Black Saturday bushfires in Victoria burnt around 4,500 hectares. In comparison, each year in northern Australia where 70 per cent of our cattle graze, we burn 100 times that area. The savanna vegetation is burnt primarily to prevent new tree growth and to stimulate the growth of high-protein green grass.
Climate Change
Gerard Wedderburn-Bisshop has extensively researched climate change in the Australian context and was a co-author of a 2014 land use discussion paper released by climate change campaign group Beyond Zero Emissions and the University of Melbourne’s Melbourne Sustainable Society Institute, along with a subsequent journal paper on the same subject. [25] [26]
In estimating that livestock production is responsible for around 50 per cent of Australia’s greenhouse gas emissions, the researchers allowed for various factors ignored or attributed to other sectors in official estimates, including land clearing for livestock production, related loss of soil carbon, tropospheric ozone from savanna fires, and the shorter-term impacts of methane emissions.
The climate change impacts of animal agriculture have adversely affected native animals directly through factors such as heat and water stress and indirectly through loss of habitat.
Conclusion
It is difficult to overstate the negative effect on Australia’s native fauna of livestock production since European settlement. The effects are ongoing and dramatic, with the sector’s strategic marketing approach seeking to portray a vastly different image to the general community.
If we are to protect and maintain our precious wildlife, we must honestly and directly address the critical problems we have created. Government support for powerful livestock industry forces would contribute to long-term adverse outcomes for our native animals and Australia as a nation.
Such support is no longer an option. The time to act is now.
Author
Supplementary video and radio interviews
ABC RADIO NATIONAL 28 FEBRUARY 2019 – LATE NIGHT LIVE (15m 10s)
ABC RADIO NATIONAL 12 AUGUST 2019 – PM (3m 57s)
Images
Gamba grass image from Levick, S.R., Setterfield, S.A., Rossiter-Rachor, N.A., Hutley, L.B., MacMaster, D. & Hacker, J.M., “Monitoring the Distribution and Dynamics of an Invasive Grass in Tropical Savanna Using Airborne LiDAR”, Remote Sens. 2015, 7, 5117-5132; doi:10.3390/rs70505117, CC BY 4.0, https://creativecommons.org/licenses/by/4.0/
Gamba grass fire on Camp Creek station in October 2012, Bushfires NT, Department of Environment and Natural Resources, Northern Territory Government. Used with permission.
References
[1] Woinarski, J., Traill, B., Booth, C., “The Modern Outback: Nature, people, and the future of remote Australia”, The Pew Charitable Trusts, October 2014, p. 5 http://www.pewtrusts.org/en/research-and-analysis/reports/2014/10/the-modern-outback
[2] Australian Government, Department of the Environment and Energy, Outback Australia, The Rangelands, https://www.environment.gov.au/land/rangelands
[3] Woinarski, J., et al., op. cit., p. 18
[4] Woinarski, J., et al., op. cit., pp. 167 & 170
[5] Martin TG, Campbell S, Grounds S (2006) Weeds of Australian rangelands. The Rangeland Journal 28, 3–26, cited in Woinarski, J., et al., op. cit., p. 148
[6] Australian Government, Department of the Environment and Energy, “Invasive pasture grasses in northern Australia – gamba grass, para grass, olive hymenachne, perennial mission grass and annual mission grass – Gamba grass”, https://www.environment.gov.au/biodiversity/threatened/threat-abatement-advices/invasive-pasture-grasses-gamba-grass
[7] Australian Government, Department of the Environment and Energy, “Question and answer: How does the listing of gamba grass and four other grasses as a key threatening process affect me?”, https://www.environment.gov.au/resource/question-and-answer-how-does-listing-gamba-grass-and-four-other-grasses-key-threatening
[8] Rossiter NA, Setterfield SA, Douglas MM, Hutley BB (2003) Testing the grass-fire cycle: alien grass invasion in the tropical savannas of northern Australia. Diversity and Distributions 9, 169-176, cited in Woinarski, J., et al., op. cit., p. 149
[9] Interview of Dr Barry Traill of The Pew Charitable Trusts by Phillip Adams, Late Night Live, ABC Radio National, “Gamba grass threatens Tropical North” 28 February 2019, https://www.abc.net.au/radionational/programs/latenightlive/gamba-grass/10858528
[10] Taylor, R., Woinarski, J. & Chatto, R. (2003) Hollow use by vertebrates in the Top End of the Northern Territory. Australian Zoologist: Vol. 32, No. 3, pp. 462-476, cited in “The Gamba Grass Nightmare”, Denise Lawungkurr Goodfellow, Nature Territory – The newsletter of the Northern Territory Field Naturalists’ Club Inc., March 2019, http://ntfieldnaturalists.org.au/site/assets/files/1584/nature_territory_-_march_2019.pdf
[11] Petty, A., “Field of nightmares: gamba grass in the Top End”, 18 Feb 2013, The Conversation, cited in Woinarski, J., et al., op. cit., p. 149
[12] Williams RJ, Bradstock RA, Cary GJ, Enright NJ, Gill AM, Liedloff AC, Lucas C, Whelan RJ, Andersen AN, Bowman DMJS, Clarke PJ, Cook GD, Hennessy KJ, York A, ‘Interactions between climate change, fire regimes and biodiversity in Australia – a preliminary assessment.’ Report to the Department of Climate Change and Department of the Environment, Water, Heritage and the Arts, Canberra, Darwin, cited in Woinarski, J., et al., op. cit., p. 149
[13] Interview of Dr Barry Traill of The Pew Charitable Trusts by Phillip Adams, Late Night Live, op. cit.
[14] Australian Government, Department of the Environment and Energy, “Invasive pasture grasses in northern Australia – gamba grass, para grass, olive hymenachne, perennial mission grass and annual mission grass – Gamba grass”, Sep 2014
[15] Roocke, N., “Gamba grass: Friend or foe?”, ABC Rural, 1 April 2018, updated 4 April 2018, https://www.abc.net.au/news/rural/2008-04-01/gamba-grass-friend-or-foe/6251774
[16] Goodfellow, D., Nature Territory – The newsletter of the Northern Territory Field Naturalists’ Club Inc., March 2019, http://ntfieldnaturalists.org.au/site/assets/files/1584/nature_territory_-_march_2019.pdf, citing Lawler, E., 2018, Protecting our natural environment: New gamba grass management plan released, media statement. Northern Territory Government, Sept. 2018 and Fitzgerald, D. & Burton, L. (2018). Indigenous rangers dismayed as NT Government allows cattle station to graze gamba grass weed. ABC News.
[17] Neale, T., “A Sea of Gamba: Making Environmental Harm Illegible in Northern Australia”, Science as Culture, January 2019, DOI: 10.1080/09505431.2018.1552933, https://www.tandfonline.com/doi/abs/10.108/09505431.2018.1552933?journalCode=csac20
[18] Interview of Dr Barry Traill of The Pew Charitable Trusts by Phillip Adams, Late Night Live, op. cit.
[19] Massy, Charles (2017), Call of the Reed Warbler : a new agriculture : a new earth. University of Queensland Press, St Lucia, Queensland
[20] Government of South Australia, “South Australia Buffel Grass Strategic Plan 2012-2017”, p. 2, https://www.pir.sa.gov.au/__data/assets/pdf_file/0019/237340/SA_Buffel_Grass_Strategic_Plan.pdf
[21] ibid., p. 3
[22] Traill, B., “Populate or perish”, The Pew Charitable Trusts Outback Program, Opinion, 12th January, 2015, http://www.pewtrusts.org/en/about/news-room/opinion/2015/01/12/populate-or-perish
[23] “Pastoral lease reform: Opportunity knocks for Western Australia”, The Pew Charitable Trusts News, 27th October, 2014, http://www.pewtrusts.org/en/about/news-room/news/2014/10/27/pastoral-lease-reform-for-western-australia
[24] 3CR “Freedom of Species“ “Gerard Wedderburn-Bisshop – The environmental impacts of livestock farming”, 7th October, 2012
[25] Longmire, A., Taylor, C., Wedderburn-Bisshop, G., “Zero Carbon Australia – Land Use: Agriculture and Forestry – Discussion Paper”, Beyond Zero Emissions and Melbourne Sustainable Society Institute of The University of Melbourne, October, 2014, https://bze.org.au/research/agriculture-farming-land-use/
[26] Wedderburn-Bisshop, G., Longmire, A., Rickards, L., “Neglected Transformational Responses: Implications of Excluding Short Lived Emissions and Near Term Projections in Greenhouse Gas Accounting”, International Journal of Climate Change: Impacts and Responses, Volume 7, Issue 3, September 2015, pp.11-27. Article: Print (Spiral Bound). Published Online: August 17, 2015, http://ijc.cgpublisher.com/product/pub.185/prod.269
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