for amending the list of key threatening processes under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
2012 Assessment Period
This nomination form is designed to assist in the preparation of nominations of threatening processes consistent with the Regulations and EPBC Act. The listing of a key threatening process under the EPBC Act is designed to prevent native species or ecological communities from becoming threatened or prevent threatened species and ecological communities from becoming more threatened.
Many processes that occur in the landscape are, or could be, threatening processes, however priority for listing will be directed to key threatening processes, those factors that most threaten biodiversity at national scale.
For a key threatening process to be eligible for listing it must meet at least one of the three listing criteria. If there is insufficient data and information available to allow completion of the questions for each of the listing criteria, state this in your nomination under the relevant question.
Note – Further detail to help you complete this form is provided at Attachment A.
If using this form in Microsoft Word, you can jump to this information by Ctrl+clicking the hyperlinks (in blue text).
Nominated key threatening process | | | Ecosystem degradation, habitat loss and species decline in arid and semi-arid Australia due to the invasion of buffel grass (Cenchrus ciliaris and C. pennisetiformis) |
| 2.CRITERIA UNDER WHICH THE KEY THREATENING PROCESS IS ELIGIBLE FOR LISTING
Please mark the boxes that apply by clicking them with your mouse.
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Criterion A
Criterion B
Criterion C
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Evidence that the threatening process could cause a native species or ecological community to become eligible for listing in any category, other than conservation dependent.
Evidence that the threatening process could cause a listed threatened species or ecological community to become eligible for listing in another category representing a higher degree of endangerment.
Evidence that the threatening process adversely affects two or more listed threatened species (other than conservation dependent species) or two or more listed threatened ecological communities.
| 3.2012 CONSERVATION THEME: Corridors and connecting habitats (including freshwater habitats)
Is the current conservation theme relevant to this key threatening process? If so, explain how.
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Corridors and connecting habitats, including freshwater habitats, are extremely relevant to the nominated threatening process (referred hereafter as the “invasion of buffel grass”) on a number of levels, including:
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Recognised landscape scale corridors.
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Biological corridors and connecting habitats.
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Physical corridors.
Landscape corridors
Buffel grass is the most significant threat to biodiversity in a number of nationally recognised landscape scale habitat corridors, as identified in the Draft National Wildlife Corridors Plan), including:
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“Trans-Australia Eco-Link”, linking northern and south Australia, and
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“East meets West”, linking the shrubland and woodlands between Eastern and Western Australia.
The management of the invasion of buffel grass along these corridors will be a key platform to ensure these corridors facilitate the maintenance of biodiversity and the provision of resilience against climate change.
Biological corridors
Unassisted invasions of buffel grass typically occur along roads and watercourses. These features are important introduction pathways whereby buffel grass can spread into new landscapes. Ephemeral watercourses and “desert rivers”, which are key biodiversity corridors in arid Australia, are the preferred environment for the establishment and spread of buffel grass in arid Australia (Albrechts and Pitts 1997). In northern South Australia and central Australia, the initial invasion of buffel grass often occurs along red-gum (Eucalyptus camaldulensis) lined ephemeral watercourses, prior to spreading out into the surrounding area (M. Ward pers. obs.). Rivers and creeklines in arid Australia provide refugia for many plant and animal species due to their enhanced nutrients, water and habitat complexity, and each of these benefits can be negatively affected by dense buffel grass infestations (Humphries et al. 1993). Furthermore, the invasion of buffel grass is very detrimental to many plant and animal species which rely on corridors in facilitating their dispersal. Recently, proposals have been submitted to the Australian Government’s Biodiversity Fund focusing on managing buffel grass along “desert rivers” in the Finke IBRA region, and across the Alinytjara Wilurara NRM Region.
The impact of Buffel grass on arid ecosystem function is significant. This is because creek lines typically act as a blockade to the spread of fire, even when dry, because the soils within the creek do not support the growth of dense, fire-fuelling grasses. Anecdotal evidence indicates that Buffel grass thrives along creek lines in dry environments (Miller et al., 2010). Thus, a feature that should prevent the spread of fire can now transport it, effectively acting as the “wick for the fire” (Humphries et al., 1992 as cited in D’antonio and Vitousek, 1992) and the fear, however sensationalised, is that Buffel grass will transform arid environments such as the Sonora Desert into African-style savannas (e.g. see http://www.youtube.com/watch?v=nQtIVzSrqZY)
Where it occurs, buffel grass is also filling in much of the usual bare-ground spacing between native grasses, shrubs and trees. This bare-ground spacing is a feature of most arid and semi-arid Australian ecosystems, in most years, and helps to stop most wildfires from becoming too extensive and from occurring too often. Buffel grass is significantly altering this ecosystem feature and enabling more catastrophic fires to occur.
Control of buffel grass along invasion pathways is therefore a priority for preventing colonisation of new regions and for limiting the ecological impacts of buffel grass both in key connecting habitats and the adjacent broadscale environment.
Invasion pathways
Man-made corridors, including roads, railways and pipelines, are significant pathways for the introduction of buffel grass (Cenchrus ciliaris and C. pennisetiformis) into un-infested regions. Buffel grass seed is spread by graders and other earthmoving equipment and the wind created by vehicles along these corridors (Griffin 1993). Disturbed ground within the corridors, particularly where increased runoff occurs, is able to be rapidly colonised by buffel grass. These corridors can therefore provide a stepping stone for buffel grass infestation into the wider environment once suitable conditions are available.
| 4.THREAT STATUS
Is the key threatening process listed under State/Territory Government legislation? Is the threat recognised under other legislation or intergovernmental arrangements?
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Although several regional Natural Resource Management (NRM) Boards and Catchment Management Authorities (CMAs) have identified buffel grass as an important natural resource management issue (South Australian Arid Lands, Alinytjara Wilurara, Western Australian Rangelands, Northern Territory, Friedel et al. 2006), buffel grass has not been declared as a registered weed under relevant legislation in any state (Grice et al. 2011). However, recent studies have demonstrated sufficient common understanding amongst a range of stakeholders that the threats posed by buffel grass to the conservation estate warrant the development of consistent policy for management of buffel grass (Friedel et al. 2011).
Despite not being listed under any state’s legislation, the threat posed by buffel grass is considered ‘very high’ in both the arid rangelands and native vegetation land uses of Australia, with 68% of Australia considered suitable to highly suitable for the establishment of significant buffel grass populations (Lawson et al 2004). As a result, there is currently a range of plans and strategies which identify and target the risk of buffel grass to EPBC matters of environmental significant at a more local scale. Examples include:
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The Draft South Australia Buffel Grass Strategy 2012-2017 identifies the significant threat of buffel grass, outlines a range of management zones to facilitate management, and promotes the formation of a state-wide taskforce to (i) coordinate and facilitate the exchange of information on control initiatives around the State, (ii) provide a clearer overview and better evaluation of the risk to the State from buffel grass, and (iii) recommend better coordination of buffel grass policy.
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The Draft Alinytjara Wilurara Fire Management Strategy identifies buffel grass as the single biggest risk to biodiversity (EPBC listed and otherwise), life and property in the Alinytjara Wilurara NRM region which constitutes about 25% of the land area of the State (Alinytjara Wilurara NRM Board 2012).
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A risk assessment performed for the biodiversity of the Olympic Dam region considered the risk posed by buffel grass to be extreme, resulting in management targets of eradicating all populations in that region (BHPB 2007)
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Buffel grass has been identified as a threat to both the natural and cultural values within the Uluru-Kata Tjuta National Park (UKTNP) and a comprehensive containment and removal policy has been developed for this World Heritage area (UKTNP 2009).
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Buffel grass has been identified as a significant threat in a range of threatened species recovery plans (EPBC listed or otherwise, see Sections 10 – 15).
Whilst not specific to buffel grass, there are parts of state plans and legislation which can have influence on the threat of buffel grass. In South Australia, for example:
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Section 4(b) (ii) of the SA Pastoral Land Management and Conservation Act, 1989, provides legislative basis for preventing the introduction of non-indigenous plants such as buffel grass in order to “prevent degradation of the land and its indigenous plant and animal life”.
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Also, Goal 4 of the State NRM Plan: Integrated management of biological threats to minimise risks to natural systems, communities and industry
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