Threatened species & ecological communities

National recovery plan for the Wongan Gully Wattle (Acacia pharangites)

Department of Environment and Conservation, Species and Communities Branch (SCB), Kensington

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Summary

Illustrations and/or further information:

Brown, A., Thomson-Dans, C. and Marchant, N. (Eds). (1998). Western Australia’s Threatened Flora. Department of Conservation and Land Management, Perth, Western Australia; Hopper, S., Van Leeuwen, S., Brown, A. and Patrick, S. (1990). Western Australia’s Endangered Flora. Department of Conservation and Land Management, Perth, Western Australia; Maslin, B.R. (1982). Studies in the genus Acacia (Leguminosae: Mimosoideae) No. 10 - Acaciaspecies of the Wongan Hills, Western Australia. Nuytsia 4(1): 29-46. Western Australian Herbarium (2006) FloraBase - Information on the Western Australian Flora. Department of Environment and Conservation Perth, Western Australia. http://www.calm.wa.gov.au/science/ .

Analysis of outputs and effectiveness of Interim Recovery Plan (IRP) 20 (1999-2002) prepared by R. Evans and A.Brown.

The criteria for failure in the previous plan (the number of individuals in populations and/or the number of populations have decreased by 10 percent or more over the term of the plan) has been met, as follows.

The number of mature plants in wild populations has decreased from 333 to 49, a decrease of 85 percent.

This is believed to have occurred due to senescence and poor recruitment resulting from a lack of suitable disturbance such as fire.

Actions carried out in the previous plan include:

Action 6 Collect Seed. DEC’s Threatened Flora Seed Centre (TFSC) and the Botanic Gardens and Parks Authority (BGPA) hold seed of this species.

Action 7 Promotion of Awareness. A two-sided poster has been distributed to relevant authorities, schools, libraries and other institutions. The species has been included in the Wongan-Ballidu Wildlife Management Program, published in 2006.
Action 10 Research into Biology and Ecology. Research into seed viability and soil seed bank dynamics has been undertaken.

Other recovery actions included in the previous plan are ongoing and are included in this revised plan.

New recovery actions included in this plan are:

Action 8 Map habitat critical to the survival of Acacia pharangites

Current status:

Acacia pharangites was declared as Rare Flora in 1986 under the Western Australian Wildlife Conservation Act 1950and is currently ranked as Critically Endangered (CR) under World Conservation Union (IUCN 1994) Red List criteria B1+2c; C2b; D due to its area of occupancy being less than 10 km2, a continuing decline in the number of mature individuals and a total population size of less than 250 mature individuals with all occurring in a single population. Following the discovery of a second population and reassessment using IUCN 2001 criteria the species now meets CR under criteria B1ab(v)+2ab(v);C2a(i). The species is listed as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The main threats are lack of suitable disturbance such as fire, a lack of recruitment, limited genetic diversity, seed predation and grazing.

Acacia pharangitesis known from two populations (totaling 49 mature plants) in an area of remnant natural vegetation in the Shire of Wongan-Ballidu, in DEC’s Avon Mortlock District. Approximately ninety five percent of native vegetation in the Shire has been cleared for agriculture (Shepherd et al. 2002).

Population 1, on private property, contains forty seven percent of mature plants. Population 2 is located in a nature reserve and contains the remaining fifty three percent of plants.

Description:

Acacia pharangites is a somewhat spindly shrub to 4 m tall. Its branches have a thick, waxy, powdery coating towards the extremities and lack hairs. Branches are scarred by raised stem-projections where phyllodes have fallen. The phyllodes are erect, straight to shallowly curved, circular in cross-section, 1.5-4 cm long, approximately 1 mm in diameter, ± a distinct pungent mucro, ± rigid, smooth, seven-nerved and blue-green with a whitish bloom. Inflorescences composed of one, occasionally two, headed racemes, with raceme axes approximately 0.5 mm long. Peduncles are ± 10 mm long and lack hairs. The basal bract is prominent, falling away before associated organs mature. Inflorescence heads are obloid, 7-10 mm long, and golden with approximately twenty five flowers. The bracteole conspicuously overlaps the flower bud. Flowers are five-merous with sepals ¼-½ united and irregularly lobed. The pods are linear, strongly raised over the seeds on alternating sides, up to 7 cm long, ± 4 mm wide, thinly leathery, with a slightly thick, waxy, powdery coating, with no hairs. Seeds are longitudinal, elliptic, 3-4 mm long, glossy and black with a yellowing aril (Maslin 2001).

Habitat requirements:

Acacia pharangites occurs in a sheltered gully within and flanking a seasonally dry creek, growing in rocky red-brown clay comprised of small stones derived from greenstone and in grey sand in the creek bed.

Habitat critical to the survival of the species, and important populations:

Given that Acacia pharangitesis ranked as Endangered (EPBC Act), it is considered that all the known habitat of wild populations is critical to the survival of the species, and that all wild populations are important populations. Habitat critical to the survival of A. pharangitesincludes the area of occupancy of the extant populations; areas of similar habitat nearby (i.e. sheltered gullies of rocky red-brown clay, flanking a seasonally dry creek and grey sand in the creek bed) and remnant vegetation that surrounds populations (this is necessary to provide habitat for pollinators and seed dispersing ant guilds) and additional occurrences of similar habitat that may contain the species or be suitable for future translocations.

Benefits to other species or ecological communities:

Recovery actions implemented to improve the quality or security of the habitat of Acacia pharangiteswill also improve the status of remnant associated vegetation containing Acacia acuminata, Acacia congesta, Allocasuarina campestris, Calothamnus asper, Melaleuca radula, Eucalyptus myriadena, Hibbertiaand Cryptandraspecies.Several threatened flora species located with A. pharangites are listed in the table below.

Conservation-listed flora species occurring in habitat of Acacia pharangites

Species name Conservation Status (Western Australia) Conservation Status (EPBC Act 1999)
Philotheca wonganensis DRF, Endangered Endangered
Acacia pygmaea DRF, Endangered Endangered
Eremophila ternifolia DRF, Vulnerable Endangered
Microcorys eremophiloides DRF, Vulnerable Vulnerable

DRF – Declared Rare Flora.

International obligations:

This plan is fully consistent with the aims and recommendations of the Convention on Biological Diversity, ratified by Australia in June 1993, and will assist in implementing Australia’s responsibilities under that convention. Acacia pharangitesis not listed under any specific international treatyr, and therefore this recovery plan does not affect Australia’s obligations under any other international agreements.

Role and interests of Indigenous people:

According to the Department of Indigenous Affairs Aboriginal Heritage Sites Register, no sites of Aboriginal significance are known at or near populations of the species covered by this recovery plan. However, the involvement of the Indigenous community is currently being sought to determine whether there are any issues or interests identified in the Plan. If no role is identified for Indigenous communities in the recovery of this species, opportunities may exist through cultural interpretation and awareness of the species.

The advice of the South West Aboriginal Land and Sea Council (SWALSC) and Department of Indigenous Affairs is being sought to assist in the identification of potential Indigenous management responsibilities for land occupied by threatened species, or groups with a cultural connection to land that is important for the species' conservation.

Continued liaison between DEC and the Indigenous community will identify areas in which collaboration will assist implementation of recovery actions.

Social and economic impact:

The implementation of this recovery plan is unlikely to cause significant adverse social and economic impacts. However, as one of the two known populations is located on private property its conservation may potentially affect farming activities. Actions will involve liaison and cooperation with stakeholders with regard to this area.

Affected interests:

Stakeholders include the owners of private property.

Evaluation of the plan’s performance: DEC in conjunction with the Avon Mortlock District Threatened Flora Recovery Team (AMDTFRT) will evaluate the performance of this recovery plan. In addition to annual reporting on progress and evaluation against the criteria for success and failure, the plan will be reviewed following five years of implementation.

Existing Recovery Actions:

The following recovery actions have been or are currently being implemented:

  1. Land managers including the private land owners with a population on their property have been made aware of the threatened nature of this species, its location and their legal obligations to protect the species.
  2. Seed was collected in 1997 and again in 1998 by staff from DEC’s Threatened Flora Seed Centre (TFSC). Seed was also collected in August and November 1996 by Staff from the Botanic Gardens and Parks Authority (BGPA). In December 2005 seed was collected from subpopulation 1a and population 2 by Joel Collins from DEC’s Avon Mortlock District.
  3. BGPA has six plants in the botanic gardens, and eleven in nursery frames.
  4. The AMDTFRT is overseeing the implementation of this recovery plan and will include it in their annual report to DEC’s Corporate Executive and funding bodies.
  5. Staff from DEC’s Avon Mortlock District office are monitoring both known populations.

Recovery plan objective:

The objective of this recovery plan is to abate identified threats and maintain or enhance viable in situ populations to ensure the long-term preservation of the species in the wild.

Recovery criteria

Criteria for success:

The number of populations have increased or the number of mature individuals in populations have increased by ten percent or more over the five year term of the plan.

Criteria for failure:

The number of populations have decreased or the number of mature individuals in populations have decreased by ten percent or more over the five year term of the plan.

Recovery actions

  1. Coordinate recovery actions
  2. Monitor populations
  3. Develop and implement fire and disturbance trials
  4. Develop and implement a fire management strategy
  5. Promote awareness
  6. Conduct further surveys
  7. Collect and store seed
  8. Map habitat critical to the survival of Acacia pharangites
  9. Obtain biological and ecological information
  10. Review the need for further recovery actions
Cover page of recovery plan

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