Acacia octonervia 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Fabales Fabaceae

Scientific Name: Acacia octonervia R.S.Cowan & Maslin

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii) ver 3.1
Year Published: 2012
Date Assessed: 2011-02-22
Assessor(s): Malcolm, P.
Reviewer(s): Hilton-Taylor, C.
Acacia octonervia is endemic to southwest Western Australia. The extent of occurrence classifies the species under the Vulnerable category (EOO ~7,800 km2). Despite that many of the known subpopulations were noted as in good condition in 1992, general threats to the habitat especially those from agriculture, increased salinity and the threat from die-back disease, shows a continuing decline in habitat quality. The species is known to occur in protected areas but these are mainly Road Reserves. The natural habitat is severely fragmented. Therefore the species is listed as Vulnerable.

Geographic Range [top]

Range Description:Acacia octonervia is endemic to Australia distributed in southwest Western Australia restricted to the area between the Fitzgerald and Young Rivers, with an outlier near Boxwood Hill.
Countries occurrence:
Australia (Western Australia)
Additional data:
Lower elevation limit (metres):50
Upper elevation limit (metres):300
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Surveys in the Esperance Area from 1966 until 1992 have found 13 separate subpopulations none of them with much more than 2,000 individuals and the smaller population with 20-50 individuals. Many of these populations were recorded as common and in good condition (Craig and Coates 2001).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:A spreading shrub to 1 m high that flowers from August to October and grows in rocky sand, rocky loam or sandy clay, in open mallee, dense low heath and open dwarf scrub.

Threats [top]

Major Threat(s): Despite the fact that the species is noted as common in the upper reaches of the Young River catchment area, most of the known populations occur on road reserves and the habitat is highly fragmented; therefore these populations are vulnerable in the long term (Craig and Coates 2001). Threatening processes in the Esperance Plains region is fair to poor with a declining trend. Threatening processes to the area include vegetation clearing and fragmentation for agriculture, hydrological changes and salinity, feral predators and herbivores, grazing by stock and weeds. In the Esperance region (ESP1 Fitzgerald subregion) approximately half of it has been cleared of native vegetation (Comer et al. 2001). Despite the fact that this species is not susceptible to root-rot fungus (Groves et al. 2009) Phytophthera is changing the composition of coastal heath and scrub communities (Australian Natural Resources Atlas 2009). Most importantly, recent news reports warn that dieback root-disease is posed to tear through the Fitzgerald National Park, despite efforts from the Project Dieback to contain the spread of the pathogen (Bennet 2010).

Conservation Actions [top]

Conservation Actions: It is known to occur within the Fitzgerald River National Park and several Road Reserves in the area. Management plans are in place to combat the spread of root-rot fungus in the region, however, continuing monitoring of the species and the threats on its populations is recommended. The species was listed as Priority Three - Poorly known Taxa, under CALM's Priority Flora List in 2001; taxa which are known from several populations, and the taxa are not believed to be under immediate threat (Craig and Coates 2001, Briggs and Leigh 1995). Currently the species is listed as Not Threatened (Smith 2010). It is also recommended that its seeds are banked as an ex situ conservation measure.

Classifications [top]

3. Shrubland -> 3.8. Shrubland - Mediterranean-type Shrubby Vegetation
3. Species management -> 3.4. Ex-situ conservation -> 3.4.2. Genome resource bank

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.4. Scale Unknown/Unrecorded
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

8. Invasive and other problematic species, genes & diseases -> 8.1. Invasive non-native/alien species/diseases -> 8.1.1. Unspecified species
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

8. Invasive and other problematic species, genes & diseases -> 8.1. Invasive non-native/alien species/diseases -> 8.1.2. Named species [ Unspecified Phytophthora ]
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

8. Invasive and other problematic species, genes & diseases -> 8.2. Problematic native species/diseases -> 8.2.1. Unspecified species
♦ timing:Ongoing    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

Bibliography [top]

Australian Natural Resources Atlas. 2009. Biodiversity Assessment - Esperance Plains. Available at: (Accessed: 16 August 2010).

Bennett, M. 2010. Dieback devastates massive slice of WA bush. The West Australian.

Briggs, J.D. and Leigh, J.H. 1995. Rare or threatened Australian plants. Centre for Plant Biodiversity Research, Canberra.

Comer, S., Gilfillan, S., Grant, M., Barrett, S. and Anderson, L. 2001. Esperance 1 (ESP1 - Fitzgerald subregion). In: Department of Conservation and Land Management (eds), A Biodiversity Audit of Western Australia’s 53 Biogeographical Subregions in 2002.

Craig, G.F. and Coates, D.J. 2001. Declared rare and poorly known flora in the Esperance district. Department of Conservation and Land Management.

Groves, E., Hollick, P., Hardy, G. and McComb, J. 2009. Appendix 2 Western Australian natives susceptible to Phytophthora cinnamomi. Available at:

IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.2). Available at: (Accessed: 17 October 2012).

Orchard, A.E. and Wilson, A.J.G. 2001. Mimosaceae, Acacia part 2. In: B.R. Maslin (ed.), Flora of Australia Volume 11B, ABRS, Canberra.

Smith, M.G. 2010. Declared Rare and Priority Flora List for Western Australia, 25 March 2010. Dept of Environment and Conservation, Como, W.A.

Citation: Malcolm, P. 2012. Acacia octonervia. In: . The IUCN Red List of Threatened Species 2012: e.T19891697A20122243. . Downloaded on 23 June 2018.
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