Purple-wood Wattle - profile

Scientific name: Acacia carneorum
Conservation status in NSW: Vulnerable
National conservation status: Vulnerable

Description

The Purple-wood Wattle (formerly Acacia carnei) is a dark green and prickly shrub to small tree, 2 - 4 m tall. Plants have a striking, deep-purple heartwood. The phyllodes (wattle leave) are rigid and needle-like, sharply pointed, four-angled and are 2 - 6.5 cm long and 1 - 3 mm wide. Flower-heads are spherical, golden-yellow in colour and are on hairy stalks 12 - 25 mm long. The pods are hard and woody with a short white downiness, straight to strongly curved and are slightly constricted between seeds. The pods are 3 - 5 cm long and 10 mm wide.

Location and habitat

Distribution
Occurs in the far western plains, south from west of Tibooburra to the Menindee area. Also has a limited distribution in SA.

Habitat and ecology

Grows in grassland and woodland in red, sandy soil; also found in Mulga communities on sand dunes, level sandy sites and alluvial accumulations along watercourses; recorded from inland semi-arid Acacia and Casuarina shrublands and woodlands.
Preferred soils are shallow, calcareous and loamy, and include brown earths, crusty alkaline soils and neutral red duplex soils; confined to red-earth dune soils in Kinchega NP as a dominant or occasionally co-dominant, usually on dune crests or slopes.
Associated species include Alectryon oleifolius, Casuarina cristata, C. pauper, Maireana pyramidata, Eucalyptus socialis and Enchyleana tomentosa.
A long-lived perennial that flowers at any time of year; rarely sets seed but produces new suckers, independent of root disturbance, either annually or biannually in two growth pulses in autumn and spring (during average or above average rainfall years).
Tends to occur in colonies of 20 to 60 plants, which are clonal; seed viability is generally low and the majority of seeds are non-dormant when released from the pods, which remain on the parent plant for several years after dehiscence.
Observed as common in gregarious groupings on sandhills and ridges; populations in Kinchega NP grow in tall shrublands, comprising a mixture of ramets from a limited number of genetically distinct individuals, with isolated populations likely to be genetically distinct.

Regional information
This species is found in the following catchment management authority regions. Click on a region name to see more details about the distribution, vegetation types and habitat preference of the species in that region.

Threats

Rabbit grazing pressure has been shown to be the cause of a lack of recruitment in populations; regeneration is severely limited by rabbit grazing, as newly emergent sucker recruits are eaten-off at the base; rabbits also contribute to mortality or dieback of established plants by stripping the bark.
Kangaroos and goats also strip the stems of phyllodes, often killing the plant.
Erosion of habitat, caused by the undermining of the soil by rabbits, exposes the roots of plants particularly on destabilised sand dunes
Cattle sheltering under trees of this species contribute to further destabilising of the soil.
The low seed viability and low rate of seedling recruitment are also major threats to the long-term survival of the species.

Recovery strategies

Priority actions are the specific, practical things that must be done to recover a threatened species, population or ecological community. The Department of Environment and Conservation has identified 19 priority actions to help recover the Purple-wood Wattle in New South Wales.

What needs to be done to recover this species?

Some form of rabbit control is necessary to maintain populations in the long-term; give high priority to further rabbit control in areas on pastoral leases, particularly following heavy rains that would result in significant suckering.
Protect from kangaroo and goat grazing.
Do not permit further clearing of potential habitat.
Protect known seed sources (successful seed production is limited to very few populations, with only two study sites representing known seed sources).
Exclude mining and destructive mineral exploration from any areas containing this species.
Initiate monitoring programs at sites with construction of rabbit, stock and goat-proof exclosures around representative populations.
Baseline surveys are required to confirm known populations and to locate new ones.

References

Auld, T.D. (1990) Regeneration in populations of the arid zone plants Acacia carnei and A. oswaldii. Proceedings of the Ecological Society of Australia 16: 267-272.
Auld, T.D. (1993) The impact of grazing on regeneration of the shrub Acacia carnei in arid Australia. Biological Conservation 65: 165-176.
Ayers, D., Nash, S. and Baggett, K. (1996) Threatened Species of Western New South Wales. NSW NPWS, Sydney.
Bowen, P.F. and Pressey, R.L. (1993) Localities and habitats of plants with restricted distributions in the Western Division of New South Wales. Occasional Paper No. 17. NSW NPWS, Sydney.
Briggs J.D. and Leigh J.H. (1996) Rare or Threatened Australian Plants. CSIRO Publishing, Australia.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992) Plants of Western New South Wales. Inkata Press, Sydney.
Davies, R.J.P. (1995) Threatened plant species management in the arid pastoral zone of South Australia. Department of Environment and Natural Resources, Kensington, South Australia.
Hall, N. and Johnson, L.A.S. (1993) The names of acacias of New South Wales - with a guide to pronunciation of botanical names. Royal Botanic Gardens, Sydney.
Maiden, J.H. (1916) Notes on Acacia, (with description of new species), No. 1. Proceedings of the Royal Society of New South Wales 49: 463-513, pp. 470-471.
Maiden, J.H. and Blakely, W.F. (1926) Descriptions of fifteen new Acacias and notes on several other species. Journal and Proceedings of the Royal Society of New South Wales 60: 171-196.
Maslin, B.R. and Pedley, L. (1982) The distribution of Acacia (Leguminosae: Mimosoideae) in Australia. Part 1. Species distribution maps. Western Australian Herbarium Research Notes 6: 1-128.
Morris, A. (1966) Plant life of the West Darling (Barrier Field Naturalists Club: Broken Hill).
Morrison, D.A. and Davies, S.J. (1991) Acacia. In Harden, G.J. (ed.) Flora of New South Wales. Volume 2. New South Wales University Press, Sydney.
Pressey, R.L., Cohn, J.S. and Porter, J.L. (1990) Vascular plants with restricted distributions in the Western Division of New South Wales. Proceedings of the Linnean Society of New South Wales 112: 213-227.
Whibley, D.J.E. (1979) Notes on Acacia carnei in South Australia. South Australian Naturalist 54(4): 12-14.
Whibley, D.J.E. and Symon, D.E. (1992) Acacias of South Australia. Revised Second Edition. South Australian Government, Adelaide.