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 Vulnerable
Listing and Conservation Advices Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [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
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument].
 
State Government
    Documents and Websites
WA:Declared Rare and Poorly Known Flora in the Central Forest Region. Part 2 (Williams, K., A. Horan, S. Wood & A. Webb, 2001) [State Species Management Plan].
State Listing Status
WA: Listed as Vulnerable (Wildlife Conservation Act 1950 (Western Australia): September 2013 list)
Scientific name Tetraria australiensis [10137]
Family Cyperaceae:Cyperales:Liliopsida:Magnoliophyta:Plantae
Species author C.B.Clarke
Infraspecies author  
Reference Bulletin of Miscellaneous Information, Kew -- Additional Series 8 (New Genera and Species of Cyperaceae) (Jun. 1908) 48.
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

The current conservation status of the Southern Tetraria, Tetraria australiensis, under Australian and State Government legislation, is as follows:

National: Listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999.

Western Australia: Listed as Declared Rare Flora under the Wildlife Conservation Act 1950 and on the Wildlife Conservation (Rare Flora) Notice 2006.

Scientific name: Tetraria australiensis

Common name: Southern Tetraria

Southern Tetraria is a perennial, rhizomatous, tufted herb/sedge, with stems that grow to 1 m high (Atkins 1998; Brown et al. 1998; Kelly et al. 1993; Paczkowska & Chapman 2000; Williams et al. 2001). The stems are terete (more commonly flat) and have three or four distant nodes (Evans et al. 2003). The numerous basal leaves are 4–5 mm broad and much shorter than the stem (Evans et al. 2003). Its cylindrical leaves have many fine, longitudinal lines. The leaves, up to 18 cm long and 6 mm wide, become shorter further up the stem. The base of the leaf encloses the stem in a blackish-brown sheath. Slender, dull, pinkish-brown inflorescences, up to 30 cm long, contain laterally flattened spikelets which are densely clustered on numerous short and erect branches. Each spikelet, about 1 cm long, contains two flowers and usually has three basal bracts. The fruit is a smooth nut that is round to elliptical (Brown et al. 1998).

Southern Tetraria is confined to the area between Perth and the South West Capes in south-west Western Australia (Atkins 1998; WA DEC 2007). The taxon is known to occur from Busselton, through Waroona and north to Serpentine (Evans et al. 2003). It occurs in the Swan and South West Natural Resource Management Regions.


The extent of occurrence is calculated to be 1243 km². The Western Australian Department of Environment and Conservation's (WA DEC) Threatened Flora Database was used to create a mimimum convex polygon.

It is likely that the previous extent of occurrence of Southern Tetraria was significantly larger than it is now. It was presumed extinct until 1993, as it had not been recorded for nearly 100 years. There is no data to indicate future declines in the extent of occurrence; however, it remains subject to the pressures associated with development (WA DEC 2007).

The area of occupancy is estimated to be 0.124 km² (or 12.4 hectares). This was calculated from the on-ground area of occupancy estimates that were recorded for three subpopulations. The area of occupancy was not recorded for the remaining nine subpopulations, so an estimate was used based on the average size of the subpopulations which are known. This estimate is likely to be somewhat inaccurate, especially as this species is common after fire and the area of occupancy may fluctuate considerably (WA DEC 2007).

Southern Tetraria is known from 11 locations, none of which are translocated (WA DEC 2007).

The species' distribution is severely fragmented. The known subpopulations occur in isolated remnant pockets of vegetation over 175 km (WA DEC 2007).

Southern Tetraria was first collected from the Serpentine River in 1872 and from the Cannington area in 1898, both in the Perth Metropolitan area, south-west Western Australia (Brown et al. 1998). The location of this species was not precisely recorded and, subsequently, the species was presumed extinct. In January 1993, the species was rediscovered east of Mundijong in an area of remnant bushland (Brown et al. 1998; Keighery 1993). Since then, targeted surveys have discovered 10 additional subpopulations (WA DEC 2007).

The following table presents the number of plants present at each subpopulation (WA DEC 2007):

Subpopulation Survey History Number of Plants Recorded Area
1 19/01/1993 1000 Not recorded
2 03/11/1993 100 Not recorded
3 06/12/1994
29/12/1999
15/12/2000
200
33
75
Not recorded
Not recorded
Not recorded
4 01/11/1995
12/11/2002
1000+
8 seedlings
Not recorded
Not recorded
5a 01/11/1995
05/07/1996
100+
30+
Not recorded
> 0.1ha
5b 02/08/1996 100 > 1 ha
6 01/02/1996
07/10/2002
100+
0*
Not recorded
Not recorded
7 21/04/1996 100+ Not recorded
8 23/06/1996 Locally common Not recorded
9 24/05/1996 Frequent Not recorded
10 03/12/2001 50 (estimated) 2 ha
11 03/12/2001 Not recorded Not recorded

*Although no plants were recorded, the observer did not regard the subpopulation as extinct because the habitat was intact and no fires had occurred recently (WA DEC 2007).

The total population size of Southern Tetraria is estimated to be 1455 mature individuals (WA DEC 2007). This figure is an estimate that is likely to be inaccurate; some populations have not been surveyed since 1993 (WA DEC 2007).

Some of the populations for this species are split into subpopulations. Subpopulations are defined by differences in land tenure and management, as well as location. Currently, population trends for this species appear stable.

Southern Tetraria undergoes regular extreme natural fluctuations in subpopulation numbers and size. It flowers en masse in the first summer following a fire, making it more conspicuous compared to other times. Being a fire ephemeral, this species is only seen after fire at some locations (Evans et al. 2003).

The species' generation length is unknown, although the taxon is short-lived and fire dependant (Evans et al. 2003). All known subpopulations are regarded as essential for the species' long-term survival (WA DEC 2007).

No hybridisation has been recorded (WA DEC 2007).

Subpopulations 1, 2, 3 and 7 occur in nature reserves which are managed for the conservation of flora and fauna but not specifically for the management of Southern Tetraria. Subpopulation 4 occurs on private property which is now managed under a conservation covenant with the National Trust of Australia (Western Australia).

The remaining subpopulations occur on private property, state forest or shire reserves (WA DEC 2007).

East of Mundijong, Southern Tetraria occurs in grey sand over clay; also described as yellow and sandy or clayey lateritic soils (Atkins 1998; Brown et al. 1998; Keighery 1993; Williams et al. 2001). The species favours winter-wet swampy depressions, drainage lines or rises surrounding swamps (Atkins 1998; Brown et al. 1998; Keighery 1993; Williams et al. 2001). It is found in open forest (Atkins 1998); Marri Corymbia calophylla woodland (Brown et al. 1998; Keighery 1993; Williams et al. 2001) over low shrubs, herbs and sedges (Brown et al. 1998; Keighery 1993); and adjacent to Pericalymma ellipticum heath (Williams et al. 2001). Associated species include Marri, Conostylis setigera, Cyathochaeta avenacea, Orange Dryandra (Dryandra aurantia), Eremaea pauciflora, Hakea ruscifolia, H. cyclocarpa, Grass Tree (Kingia australis), Blue Leschenaultia (Lechenaultia biloba), Melaleuca sp., Mesomelaena tetragona, Pericalymma ellipticum, Tetraria octandra and Xanthorrhoea preissii (Evans et al. 2003).

An old collection from Serpentine near Perth was from open forest on sandy soil (Kelly et al. 1993).

Southern Tetraria flowers in early summer during December, and sometimes November (Atkins 1998; Brown et al. 1998; Keighery 1993; Paczkowska & Chapman 2000; Williams et al. 2001). The slender dull pinkish-brown inflorescences are up to 30 cm long (Brown et al. 1998; Kelly et al. 1993; Paczkowska & Chapman 2000; Williams et al. 2001). Flowers appear en masse early in the summer after fire (Keighery 1993; Keighery et al. 1996; Williams et al. 2001).

Southern Tetraria flowers are small and insignificant, but, this species is particularly inconspicuous when not in flower. This species occurs with another sedge (Tetraria octandra) which has a different flowering period (WA DEC 2007).

Surveying of Southern Tetraria is appropriate in suitable habitat in the middle of summer or post-fire when this species is most likely to be actively growing and flowering (WA DEC 2007). Fire is known to be a trigger for flowering and some experts suggest that this species is dependant on fire events to flower (Evans et al. 2003).

Southern Tetraria is vulnerable to the following threats:

Fire
Fire is necessary to stimulate growth and flowering in Southern Tetraria. However, too frequent fire may be detrimental to the long-term management of this species. As a fire ephemeral, this species flowers en masse post-fire. It is not known to flower without a fire trigger (Evans et al. 2003).

Land clearing
Land clearing for urban development, infrastructure and agriculture has had a significant impact on the species. Subpopulation 10 is directly in the path of the proposed Tonkin Highway extension. However, according to the Main Roads website (Main Roads 2007), there are no plans to develop the extension at this time.

Dieback caused by Phytophthora cinnamomi
The susceptibility of this species to dieback caused by Phytophthora cinnamomi is unknown (Williams et al. 2001), however, some resistance has been observed in the field (Evans et al. 2003).

Subpopulations of Southern Tetraria are vulnerable to the following threats (WA DEC 2007):

Subpopulation Number Current Condition Past Present Potential Future
1 Unknown Weeds, rubbish dumping, fire Weeds Weeds, fire
2 Unknown      
3 Healthy     Weeds, recreational activities
4 Moderate-Poor Fire, weeds (veldt grass, Ehrharta erecta), road maintenance activities Fire, weeds (veldt grass), road maintenance activities Fire, weeds (veldt grass), road maintenance activities
5A Unknown Grazing (sheep), weeds, fire, mineral and sand mining    
5B Unknown Grazing (sheep), weeds, fire, mineral and sand mining   Mining
6 Healthy-moderate Gravel extraction, weeds, fire   Gravel extraction, weeds
7 Healthy Track and phone line maintenance, weeds, fire Weed invasion Weed invasion
8 Unknown Recreational activities, weeds    
9 Unknown      
10 Moderate Road and drain maintenance activities, weeds, clearing Maintenance activities, weeds Proposed Tonkin Hwy extension
11 Unknown Trampling associated with recreation activities from a pony club, track maintenance Trampling associated with recreation activities from a pony club, track maintenance Trampling associated with recreation activities from a pony club, dieback, lack of fire to stimulate regeneration

The following priority actions are listed by Evans and colleagues (2003) and Williams and colleagues (2001):

  • Encourage best management and maintain close liaison with landowners and communities in the Ambergate area.
  • Monitor populations annually.
  • Implement control of invasive weeds, and rehabilitate with local species where required.
  • Collect seed for long-term storage, inititiate ex situ propogation and consider translocation to suitable sites in conservation reserves.
  • Resurvey all populations and install threatened flora markers.
  • Conduct further surveys in potential habitat during the species' flowering period, focusing on areas recently burnt.
  • Develop and implement a fire management strategy.
  • Review fire plan for Ruabon Reserve.

Management documents relevant to Southern Tetraria include Threatened flora of the Swan Region (Evans et al. 2003) and Declared rare and poorly known flora in the Central Forest Region (Williams et al. 2001).

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
Energy Production and Mining:Mining and Quarrying:Habitat destruction, disturbance and/or modification due to mining activities Declared Rare and Poorly Known Flora in the Central Forest Region. Part 2 (Williams, K., A. Horan, S. Wood & A. Webb, 2001) [State Species Management Plan].
Human Intrusions and Disturbance:Recreational Activities:Disturbance, especially from human recreational activities and development Declared Rare and Poorly Known Flora in the Central Forest Region. Part 2 (Williams, K., A. Horan, S. Wood & A. Webb, 2001) [State Species Management Plan].
Human Intrusions and Disturbance:Recreational Activities:Habitat degradation associated with recreational activities such as horse riding Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation Ehrharta erecta (Panic Veldtgrass) Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Vegetation and habitat loss caused by dieback Phytophthora cinnamomi Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [Conservation Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [Conservation Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate prescribed regimes and/or vegetation management to control fire regimes Declared Rare and Poorly Known Flora in the Central Forest Region. Part 2 (Williams, K., A. Horan, S. Wood & A. Webb, 2001) [State Species Management Plan].
Residential and Commercial Development:Residential and Commercial Development:Habitat modification (clearance and degradation) due to urban development Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [Conservation Advice].
Species Stresses:Indirect Species Effects:Low numbers of individuals Declared Rare and Poorly Known Flora in the Central Forest Region. Part 2 (Williams, K., A. Horan, S. Wood & A. Webb, 2001) [State Species Management Plan].
Transportation and Service Corridors:Roads and Railroads:Development and/or maintenance of roads Commonwealth Conservation Advice on Tetraria australiensis (Southern Tetraria) (Threatened Species Scientific Committee, 2008r) [Conservation Advice].

Atkins, K.J. (1998). Conservation Statements for threatened flora within the regional forest agreement region for Western Australia. Page(s) 1-95. Western Australia: Department of Conservation and Land Management.

Brown, A., C. Thomson-Dans & N. Marchant, eds. (1998). Western Australia's Threatened Flora. Como, Western Australia: 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.

Keighery, G.J. (1993). Re-discovery of Tetraria australiensis C.B.Clarke (Cyperaceae). The Western Australian Naturalist. 19(3):268. Nedlands, WA: Western Australian Naturalists' Club.

Keighery, G.J., B.J. Keighery & N. Gibson (1996). Floristics of Reserves and Bushalnd Areas of the Busselton Area (System I), Part III: Floristics of Ruabon Nature Reserve. Nedlands: WA Wildflower Society.

Kelly, A.E., A. Taylor, M.A. Langley, A. Spooner & D.J. Coates (1993). Declared Rare Flora and Other Plants in Need of Special Protection in the Metro Area. Como, Western Australia: Department of Conservation and Land Managment.

Main Roads Western Australia (2007). [Online]. Available from: http://www.mainroads.wa.gov.au/NR/mrwa/run/start.asp [Accessed 09-09-2008].

Paczkowska, G. & A.R. Chapman (2000). The Western Australian Flora, A Descriptive Catalogue. The Wildflower Society of Western Australia (Inc.), the Western Australian Herbarium, Department of Conservation and Land Management and the Botanic Gardens & Parks Authority.

Western Australia Department of Environment and Conservation (WA DEC) (2007). Records held in DEC's Declared Flora Database and rare flora files. Perth, Western Australia: Department of Environment and Conservation.

Williams, K., A. Horan, S. Wood & A. Webb (2001). Declared Rare and Poorly Known Flora in the Central Forest Region. Part 2. [Online]. Western Australian Wildlife Management Program No. 33. Department of Conservation and Land Management. Available from: http://www.dpaw.wa.gov.au/plants-and-animals/threatened-species-and-communities/threatened-plants.

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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). Tetraria australiensis in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sun, 31 Aug 2014 11:01:15 +1000.