Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Endangered
Listing and Conservation Advices Commonwealth Listing Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cn) [Listing Advice].
 
Commonwealth Conservation Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2008zt) [Conservation Advice].
 
Recovery Plan Decision Recovery Plan not required, included on the Not Commenced List (1/11/2009).
 
Adopted/Made Recovery Plans
Federal Register of
    Legislative Instruments
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (45) (14/08/2006) (Commonwealth of Australia, 2006j) [Legislative Instrument].
 
State Government
    Documents and Websites
WA:Threatened flora of the Western Central Wheatbelt (Collins, J., 2009) [State Species Management Plan].
WA:Western Australian Wildlife Management Program No. 28. Declared Rare and Poorly Known Flora in the Moora District (Patrick, S.J. & A.P. Brown, 2001) [State Species Management Plan].
State Listing Status
WA: Listed as Endangered (Wildlife Conservation Act 1950 (Western Australia): September 2013 list)
Scientific name Acacia chapmanii subsp. australis [65249]
Family Fabaceae:Fabales:Magnoliopsida:Magnoliophyta:Plantae
Species author  
Infraspecies author R.S.Cowan & Maslin
Reference Cowan, R.S. & Maslin, B.R. (1999) Acacia miscellany 18. The taxonomy of miscellaneous species with sharply pungent phyllodes in Acacia section Plurinerves (Leguminosae: Mimosoideae). Nuytsia 12(3): 457 [tax. nov.]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images
http://florabase.dec.wa.gov.au/browse/profile/14059

Scientific name: Acacia chapmanii subsp. australis (Cowan & Maslin 1999).

Acacia chapmanii subsp. australis is a low compact shrub growing to 50 cm high. The phyllodes are subterete to flat, recurved and 20-30 mm long by 0.7-1 mm in diameter. The inflorescences are held on 12-19 mm long peduncles, are singular and held in the axils. Each globular inflorescence holds 24-27 flowers, are bright light golden yellow in colour and about 5 mm in diameter (CALM 2005; Cowan & Maslin 1999; Maslin 2001; Patrick & Brown 2001).

Acacia chapmanii subsp. australis is endemic to Western Australia and is known from four populations near the town of Bolgart approximately 120 km north-east of Perth (CALM 2005).

Acacia chapmanii subsp. australis covers a long narrow area approximately 17 km by 1 km (approximately 17 km²) (WA Herbarium 2004). There is little data to show a past or future decline in the extent of occurrence although populations 2 and 3 are small (15 and 7 plants respectively) and located on shire road verges which have very tenuous security. The loss of these plants would represent a decline in the number of known occurrences and possibly a decline in the extent of occurrence (CALM 2005).

The total area of occupancy for the Acacia chapmanii subsp. australis is estimated to be approximately 7.35 ha or 0.075 km². The area of occupancy of each population is as follows (CALM 2005):

  • Population 1a: 200x100 m
  • Population 1b: 300x100 m
  • Population 2: 100x30 m
  • Population 3: 25x30 m
  • Population 4a: 250x60 m
  • Population 4b: 15x15 m
  • Population 4c: 2x50 m
  • Population 4d & e: 150x30 m

There is little data to indicate a past decline in the area of occupancy for all populations although the health of many plants at population 1b has declined significantly in recent years with a large number of plants recorded as dead when this site was last surveyed in July 2003. Therefore, the area of occupancy of living plants is declining. If this trend continues there may be a significant loss in the area of occupancy in the future (CALM 2005).

There are no translocated populations of Acacia chapmanii subsp. australis. A limited amount of seed material has been collected and is currently stored at the West Australian Threatened Flora Seed Centre (TFSC 2005). Some of this material has been used in a disturbance trial at population 1 and more may be made available should a translocation program be required in the future (CALM 2005).

The four known populations of Acacia chapmanii subsp. australis occur in areas of remnant vegetation near Bolgart. Much of the surrounding area has been cleared for agriculture and therefore the species' distribution is fragmented. Population 1 occurs within a 445 ha conservation reserve but the remaining three populations are found within road/rail reserves or a small area which is a shire reserve (CALM 2005).

A number of surveys have been carried out for A. chapmanii subsp. australis since 1992 (CALM 2005).

  • Staff from CALM Science division have conducted surveys for the species in areas of suitable habitat over two seasons during the mid 1990s. No new populations were located and the species was thought to occur at only 2 locations.
  • A contract botanist with CALM conducted flora surveys for this species in likely habitat areas during 1995 and 1996, but without success.
  • Another contract botanist with CALM undertook surveys for this species during September-October 2002. A number of sites were surveyed. However, only the two populations known at that time were located.
  • Staff from CALM Swan Region surveyed the nature reserve population in 2002.
  • A rare flora volunteer has conducted extensive surveys throughout the entire area for numerous different taxa over many years, and was able to locate the additional populations (Populations 3 and 4) during 2003.

Staff from CALM Science Division consider the likelihood of locating additional populations is small. Acacia chapmanii subsp. australis occurs in low-heath areas, of which there is little remaining vegetation. While there may be some remnants left on private property many have been grazed, or are now saline, so the chance of locating additional viable populations is unlikely (CALM 2005).

The total population size for Acacia chapmanii subsp. australis is 789 mature individuals across the four populations (CALM 2005).

Population 1 has been further split into two smaller populations which occur within the same reserve but are separated by less than 500 m. Population 4 is divided into five smaller populations due to the scattered distribution of plants in a small area of native vegetation which covers several land tenure types including road, shire and rail reserves (CALM 2005).

Population 1: occurs in a nature reserve and is made up of 2 smaller populations.

Population 1a: contains approximately 150-200 mature plants.

Population 1b: contained 7 mature plants and lots of dead plants when it was last surveyed (24/7/03). The cause of the decline in this population has not been determined but salinity levels and the presence of the plant pathogen Phytophthora cinnamomi have been tested for, but not found to be factors. A small disturbance trial incorporating trial burns, application of smoke water, and control plots is currently being carried out to try and stimulate this declining population.

Population 2: occurs on a shire road reserve and contained 15 mature plants which were moderately healthy when last surveyed (10/9/2002).

Population 3: also occurs on a shire road reserve and contained 4 mature adults and 3 seedlings that were recorded as being in poor health when last surveyed (4/3/2003).

Population 4: contains a number of scattered smaller populations that occur in an area of bushland that covers several land tenure types including rail, road and gravel reserves. All smaller populations of population 4 were last surveyed on the 4/3/2003.

Population 4a: occurs on a road reserve containing 46 mature adults and 76 dead plants. Recorded as healthy to poor (dead).

Populations 4b & c: occur in a gravel reserve and contain 3 plants each (total 6 mature adults). Condition is moderately healthy.

Populations 4d & e: occur in an area of road and rail reserve and contain 561 mature adults that are generally healthy.

The available data indicate that there has been a decline in the condition and size of populations 1, 3 and 4 with dead plants recorded at all three locations. This decline is particularly concerning for population 1 which is the only population found in a conservation reserve and where a large number of dead plants have been recorded in the last 2-3 years. CALM records indicate there were approximately 400 plants at population 1 in 1992 and this has been reduced to approximately 179 live plants in 2003 with large numbers of dead plants also seen (CALM 2005).

Hydrological investigations have been carried out to try and determine the cause of this decline and have excluded salinity as the cause. Soil testing for the fungal diseases Phytophthora cinnamomi and Armillaria have also failed to isolate a cause for these deaths. A small disturbance program is currently being carried out to try and stimulate seedling recruitment among some of the areas of dead plants This trial includes a number of replicated plots which are treated by the application of smoke water, controlled burning or control plots. If the cause of this decline cannot be identified and addressed these populations are likely to further decline in the future (CALM 2005).

It is unknown if Acacia chapmanii subsp. australis undergoes extreme natural fluctuations. However, field evidence suggests that this species is an ephemeral seeder, regenerating after fire, and therefore it may undergo fluctuations in population numbers as a response to fire or other disturbance events (CALM 2005).

The generation length of this species is unknown. However there have been no fire events at population 1 for many years (at least not since 1980, possibly longer). The plants at this population are therefore likely to be at least 24 years old and the population is currently in decline, possibly due to senescence (old age) (CALM 2005).

Given there are only four known populations and approximately 789 individuals of Acacia chapmanii subsp. australis, all known populations would be considered important for this species' long-term survival and recovery. Population 1 is the only population found in a conservation reserve but the health of plants is declining. Population 4 contains the most plants and the majority of these are considered to be healthy although the land tenure of this habitat is not secure (CALM 2005).

Population 1 is the only population within the conservation reserve system. The remaining populations occur in road, rail or a shire gravel reserves and are therefore less secure (CALM 2005).

Acacia chapmanii subsp. australis is recorded for areas of sand, sandy gravel or sandy clay with laterite in open low woodland over low heath or shrubland. It is sometimes found in winter wet areas (CALM 2005; Patrick & Brown 2001; WA Herbarium 2005).

Species associated with Acacia chapmanii subsp. australis include Eucalyptus wandoo, E. calophylla, Xanthorrhoea preissii, Dryandra armarta, Hakea incrassata, H. trifurcata, Leptospermum erubescens and Melaleuca sp. (WA Herbarium 2005).

Populations of two other species of rare flora, Hydatella leptogyne and Eleocharis keigheryi, are found in the same nature reserve as population 1 and may benefit from any recovery actions carried out for this species (CALM 2005).

Details of the ages of sexual maturity, life expectancy and natural mortality of Acacia chapmanii subsp. australis are unknown. However plants at population 1 are thought to be at least 24 years old. This population is currently in decline and the recorded plant deaths may be as a result of senescence (CALM 2005).

Acacia chapmanii subsp. australis flowers from August to September. Immature pods have been recorded from October to November and mature pod have been collected in December (Cowan & Maslin 1999; TFSC 2005; WA Herbarium 2005). Little is known about the requirements for flower and fruit production (CALM 2005).

Acacia chapmanii subsp. australis has a superficial resemblance to Acacia acellerata which has a more southerly distribution between Cranbrook and Ravensthorpe and is most readily distinguished by its 16-nerved phyllodes that are not continuous with the branchlets, paired peduncles and undulate pods (Cowan & Maslin 1999).

The more typical subspecies, A. chapmanii subsp. chapmanii, has spinose stipules, and terete straight phyllodes while A. chapmanii subsp. australis has no spines on the stipules and the phyllodes are subterete to flat and gently recurved. The two subspecies have disjunct distributions with A. champanii subsp. chapmanii found further north between Three Springs and Marchagee (Cowan & Maslin 1999).

Any additional survey should be focused on remnant vegetation in similar soil and vegetation types. Survey is easier when plants are in flower (August to September) as the plants are more easily detected (CALM 2005).

There are a number of current and potential threats to Acacia chapmanii subsp. australis including salinity, weed invasion, disease, lack of recruitment, senescence and climate change (CALM 2004). A number of these threats are likely to interact and be synergistic in their effects.

Laboratory testing for Phytophthora cinnamomi susceptibly showed a 30% death rate, suggesting that Acacia chapmanii subsp. australis has variable to intermediate susceptibility to the pathogen (Shearer 2004). Tissue samples collected during 2003 from this species and adjacent Eucalyptus wandoo at population 1 failed to isolate either Armillaria or Phytophthora, so plant disease is unlikely to be the cause of the decline in this population (CALM 2005).

Population Past Present Future
1 Unknown Lack of recruitment, possibly lack of disturbance Possibly plant disease, changed hydrology & climate change
2 Clearing Road maintenance, Weed invasion Possibly plant disease and climate change
3 Clearing Road maintenance, Weed invasion Possibly plant disease and climate change
4 Clearing Road/Rail maintenance, Weed invasion Possibly plant disease and climate change

Field evidence suggests that Acacia chapmanii subsp. australis is an ephemeral seeder, regenerating after fire. Given the observed low numbers of seedpods, soil held seed stores might be low and this could limit post fire recruitment (CALM 2005).

There have been no fire events recorded for population 1 since at least 1980, possibly longer and therefore these plants may be aging and require a disturbance even to regenerate. A disturbance trial is currently underway to try and stimulate regeneration at this site (CALM 2005).

Population 1 occurs in a nature reserve and had been considered secure. This population now appears to be threatened and in decline with large numbers of plants deaths recorded within the last few years. There have been a number of hypotheses suggested to explain the decline of the plants at population 1 including; salinity, water-logging, water runoff, natural senescence, rainfall deficit (climate change), lack of germination triggers and disease (CALM 2005).

Hydrological investigations have eliminated the role of increased salinity and water-logging as causal factors, while consultation and sampling by CALM pathologists suggest that pathogens are not a primary factor in plant decline and lack of recruitment. A disturbance trial is currently being carried out by staff from CALM's Swan Region to try and stimulate recruitment by burning some of the dead plants in the reserve. A limited amount of seed material was also added to some of the trial plots to investigate if low levels of seed set are affecting recruitment (CALM 2004).

The owners or managers of the land parcels containing populations 2, 3 and 4 have been notified and advised of their legislative responsibilities to protect the plants. Legislative protection under the Wildlife Conservation Act (1950) and clearing provisions under the Environmental Protection Act (1986) provide legal protection from clearing and other human physical disturbance to the plants and population sites (CALM 2005).

This species was first described by Cowan & Maslin (1999).

There is currently no specific Interim Recovery Plan (IRP) or Recovery Plan for Acacia chapmanii subsp. australis but it is included in the Wildlife Management Program for Declared Rare and Poorly Known Flora in the Moora District (Patrick & Brown 2001) and an NHT report on the Rare Flora of the Swan Region (Evans et al. 2003). An IRP will be prepared for this species in accordance with CALM's draft Policy Statement 9 (CALM 2004).

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Commonwealth Listing Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cn) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Presence of pathogens and resulting disease Commonwealth Conservation Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2008zt) [Conservation Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Commonwealth Conservation Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2008zt) [Conservation Advice].
Natural System Modifications:Other Ecosystem Modifications:Changes in hydrology leading to rising water tables and dryland salinity NON-APPROVED Commonwealth Conservation Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cx) [Conservation Advice].
Species Stresses:Indirect Species Effects:Low numbers of individuals Commonwealth Listing Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cn) [Listing Advice].
Species Stresses:Indirect Species Effects:Poor recruitment (regeneration) and declining population numbers Commonwealth Listing Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cn) [Listing Advice].
Species Stresses:Indirect Species Effects:Population senescnce and lack of recruitment Commonwealth Listing Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cn) [Listing Advice].
Transportation and Service Corridors:Transportation and Service Corridors:Road and rail maintenance works Commonwealth Listing Advice on Acacia chapmanii subsp. australis (Threatened Species Scientific Committee, 2006cn) [Listing Advice].

CALM (2004). Draft Policy Statement No 9. Conserving Threatened Species and Ecological Communities (Revised). Western Australian Department of Conservation and Land Management.

Evans, R., N. Willers & D. Mitchell (2003). Threatened flora of the Swan Region. Unpublished report to the Department of Conservation and Land Management and Environment Australia.

IUCN (2001). IUCN Red List Categories and Criteria version 3.1. IUCN, Gland Switzerland.

Maslin, B.R. (2001). Wattle. Acacias of Australia. Interactive Identification CD. ABRS and CALM, Collingwood.

Maslin, B.R. & A.R. Chapman (1999). Acacia miscellany 19. The taxonomy of some Western Australian species of Acacia section Juliflorae with 4-merous flowers (Leguminosae: Mimosoideae). Nuytsia. 12(3):469-486.

Patrick, S.J. & A.P. Brown (2001). Western Australian Wildlife Management Program No. 28. Declared Rare and Poorly Known Flora in the Moora District. [Online]. Perth, Western Australia: Department of Conservation and Land Management. Available from: http://www.dpaw.wa.gov.au/plants-and-animals/threatened-species-and-communities/threatened-plants.

Shearer, B. (2004). Quantification of the susceptibility of the native flora of the South-West Botanical Province, Western Australia to Phytophthora cinnamomi. Australian Journal of Botany. 52.

Shepherd, D.P., G.R. Beeston & A.J.M. Hopkins (2002). Native vegetation in Western Australia : extent, type and status. Resource management technical report 249, Western Australia Department of Agriculture, South Perth.

Threatened Flora Seed Centre (TFSC) (2005). Records held in the Department of Conservation and Land Management's Threatened Flora Seed Centre database. Perth, Western Australia: Department of Conservation and Land Management.

Western Australian Department of Conservation and Land Management (WA CALM) (2005). Records held in CALM's Declared Flora Database and Rare flora files. Perth, Western Australia: WA CALM.

Western Australian Herbarium (2005). FloraBase - The Western Australian Flora. [Online]. Perth, Western Australia: Department of Conservation and Land Management. Available from: http://florabase.calm.wa.gov.au/.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Acacia chapmanii subsp. australis in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Wed, 17 Sep 2014 03:18:53 +1000.