This Conservation Advice was approved by the Minister / Delegate of the Minister on: 3/07/2008. Approved Conservation Advice (s266B of the Environment Protection and Biodiversity Conservation Act 1999) Approved Conservation Advice for Acacia aphylla (Leafless Rock Wattle)
This Conservation Advice has been developed based on the best available information at the time this conservation advice was approved.
Description Acacia aphylla, Family Mimosaceae, also known as Leafless Rock Wattle, is a leafless, erect, widely branching shrub to 2.3 m high with golden yellow spherical flower heads (Kelly et al., 1990; Brown et al., 1998; Orchard & Wilson, 2001). Conservation Status Leafless Rock Wattle is listed as vulnerable. This species is eligible for listing as vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) as, prior to the commencement of the EPBC Act, it was listed as vulnerable under Schedule 1 of the Endangered Species Protection Act 1992 (Cwlth). The species is also listed as rare flora under the Wildlife Conservation Act 1950 (Western Australia).
Distribution and Habitat Leafless Rock Wattle is restricted to two areas about 60 km apart, in the Darling Range, east of Perth, and in the Northam area, south-west Western Australia (Brown et al., 1998). It occurs at two general localities: the Hidden Valley area in the Helena River valley, several kilometres downstream from Mundaring Weir, and Spencers Brook, south of Northam (Court, 1978; Leigh et al., 1984; Brown et al., 1998). It is found in Clackline and Mokine Nature Reserves, both containing less than 1000 plants (Briggs & Leigh, 1996). This species occurs within the Swan and Avon (Western Australia) Natural Resource Management Regions. This species is largely associated with laterite and granite outcrops on hillsides (Kelly et al., 1990; Atkins, 1998; Brown et al., 1998; Orchard & Wilson, 2001). Individuals may grow in rock crevices (Kelly et al., 1990; Brown et al., 1998; Orchard & Wilson, 2001). Soils may be sand, loam, clay or gravel and brown or yellow in colour (Atkins, 1998; Paczkowska & Chapman, 2000). It grows in open forest dominated by Jarrah (Eucalyptus marginata) and Marri (Corymbia calophylla), or woodland dominated by York Gum (E. loxophleba) (Leigh et al., 1984; Kelly et al., 1990). Associated understorey species include Spindly Grevillea (Grevillea endlicheriana), Sea Urchin Hakea (Hakea petiolaris), and Australian Grass Tree (Xanthorrhoea preissii) (Leigh et al., 1984). The distribution of this species overlaps with the “Shrublands and Woodlands of the eastern Swan Coastal Plain” EPBC Act-listed threatened ecological community.
Threats Little is known of the threats to Leafless Rock Wattle. The main potential threat is vulnerability to extended summer droughts, as it grows in shallow soils (Atkins, 1998; Brown et al., 1998). Its susceptibility to dieback caused by Phytophthora cinnamomi is unknown, although Acacia species are generally found to be quite resistant (Kelly et al., 1990; Atkins, 1998). This species may also be threatened by inappropriate fire regimes.
Acacia aphylla Conservation Advice - Page 1 of 3 This Conservation Advice was approved by the Minister / Delegate of the Minister on: 3/07/2008. Research Priorities Research priorities that would inform future regional and local priority actions include: • Design and implement a monitoring program. • More precisely assess population size, distribution, ecological requirements and the relative impacts of threatening processes. • Undertake survey work in suitable habitat and potential habitat to locate any additional populations.
Regional and Local Priority Actions The following priority recovery and threat abatement actions can be done to support the recovery of Leafless Rock Wattle. Habitat Loss, Disturbance and Modification • Monitor known populations to identify key threats. • Monitor the progress of recovery, including the effectiveness of management actions and the need to adapt them if necessary. • Identify populations of high conservation priority. • Manage any changes to hydrology that may result in changes to the water table levels or increased run-off. • Suitably control and manage access on private land. • Minimise adverse impacts from land use at known sites. • Investigate further formal conservation arrangements such as the use of covenants, conservation agreements or inclusion in reserve tenure. Fire • Develop and implement a suitable fire management strategy for Leafless Rock Wattle. • Identify appropriate intensity and interval of fire to promote seed germination or vegetation regeneration. • Provide maps of known occurrences to local and state Rural Fire Services and seek inclusion of mitigative measures in bush fire risk management plans, risk register and/or operation maps. Diseases, Fungi and Parasites • Develop and implement suitable hygiene protocols to protect known sites from further outbreaks of dieback due to Phytophthora cinnamomi. Conservation Information • Raise awareness of Leafless Rock Wattle within the local community. Enable Recovery of Additional Sites and/or Populations • Undertake appropriate seed collection and storage. • Investigate options for linking, enhancing or establishing additional populations. • Implement national translocation protocols (Vallee et al., 2004) if establishing additional populations is considered necessary and feasible.
This list does not necessarily encompass all actions that may be of benefit to Leafless Rock Wattle, but highlights those that are considered to be of highest priority at the time of preparing the conservation advice.
Existing Plans/Management Prescriptions that are Relevant to the Species • The Shire of Northam Local Planning Strategy is a council document that covers how threatened flora, including Leafless Rock Wattle, are protected in the Shire (O’Brien Planning Consultants et al., 2005), Acacia aphylla Conservation Advice - Page 2 of 3 This Conservation Advice was approved by the Minister / Delegate of the Minister on: 3/07/2008. • Management of Significant Flora Values in South-West Forests and Associated Ecosystems (Hearn et al., 2003), • Nature Reserves of the Shire of Northam and York Management Plan (CALM, 1986), • The national Interim Recovery Plan for the Eastern Shrublands and Woodlands (Swan Coastal Community 20C) 2000-2003 (English & Blyth, 2000), and • Threat Abatement Plan for Dieback Caused by the Root-Rot Fungus Phytophthora Cinnamomii (EA, 2001). These prescriptions were current at the time of publishing; please refer to the relevant agency’s website for any updated versions.
Information Sources: Atkins, KJ 1998, Conservation Statements for threatened flora within the regional forest agreement region for WA, pp. 1-95, Department of Conservation & Land Management, Como, WA. Briggs, JD & Leigh, JH 1996, Rare or Threatened Australian Plants 1995 revised edition, CSIRO Publishing, Collingwood. Brown, A, Thomson-Dans, C & Marchant, N (Eds), 1998, Western Australia's Threatened Flora, Department of Conservation & Land Management, Como, WA. Court, AB 1978, ‘Three new species of Acacia (Mimosaceae) from Western Australia’, Nuytsia, vol. 2, no. 4, pp. 168-177. Department of Conservation and Land Management (CALM) WA 1986, Nature Reserves of the Shire of Northam and York Management Plan, Department of Conservation and Land Management, Como, WA, viewed 30 March 2008,
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