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 Critically Endangered
Listing and Conservation Advices Commonwealth Listing Advice on Tetratheca gunnii (Shy Susan) (Threatened Species Scientific Committee, 2001bp) [Listing Advice].
 
Recovery Plan Decision Recovery Plan required, this species had a recovery plan in force at the time the legislation provided for the Minister to decide whether or not to have a recovery plan (19/2/2007).
 
Adopted/Made Recovery Plans Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
 
Other EPBC Act Plans Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi (Department of the Environment, 2014a) [Threat Abatement Plan].
 
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].
 
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (05/10/2001) (Commonwealth of Australia, 2001c) [Legislative Instrument].
 
State Government
    Documents and Websites
TAS:Tetratheca gunnii (shy pinkbells): Species Management Profile for Tasmania's Threatened Species Link (Threatened Species Section (TSS), 2013b) [Internet].
TAS:Listing Statement Shy Susan Tetratheca gunnii (Threatened Species Unit, 1998b) [Information Sheet].
State Listing Status
TAS: Listed as Endangered (Threatened Species Protection Act 1995 (Tasmania): September 2012 list)
Scientific name Tetratheca gunnii [14415]
Family Tremandraceae:Polygalales:Magnoliopsida:Magnoliophyta:Plantae
Species author J.D.Hook.
Infraspecies author  
Reference Flora Tasmaniae 1: 36, t. VII B (24 Oct. 1855).
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

Scientific name: Tetratheca gunnii

Common name: Shy Susan

The Shy Susan is a small herbaceous perennial with a delicate, straggling growth form (Barker 1996; Potts & Barker 1999). This erect shrub generally grows to 30 cm high (Brown et al. 1986; Leigh & Briggs 1992; Thompson 1976) but one individual was recorded at 80 cm high (Brown et al. 1986). This species is also described as an 'undershrub' with long, slender and wiry branches, 15—50 cm long, that tend to trail through associated plants (Potts & Barker 1999). Leaves are small (2—6 mm long and 0.5—1.5 mm wide), alternate, elliptical to linear, end in blunt points and are often surrounded by very small, stiff hairs. Flowers are usually abundant and vary in colour from pale lilac to deep pink-purple (Brown et al.1986).

The Shy Susan occurs on serpentine outcrops in the foothills of the Dazzler Range near Beaconsfield (Potts & Barker 1999), on the north coast of Tasmania (Barker 1996; Thompson 1976). The species was thought to be extinct until its rediscovery in 1985 (Brown et al. 1986; Leigh et al.1984), as it had not been seen since 1843 (Leigh & Briggs 1992).

The species has a linear range of 5 km, an extent of occurrence of 5 km2 and an area of occupancy of approximately 0.6 ha (0.006 km2) (Potts & Barker 1999).

Tetratheca gunnii is cultivated at the Royal Tasmanian Botanical Garden, Hobart (CHABG 1994). Friends of the Gardens propagate plants at the Royal Tasmanian Botanical Gardens from stock plants being maintained by the Tasmanian Threatened Species Unit. Approximately 50 clones have been propagated from cuttings taken from wild plants. Plants are distributed amongst the community for planting in home gardens (Potts & Barker 1999).

When the Shy Susan was rediscovered in 1985, a total of 24 individuals were identified in four populations. One population contained 20 individuals, one contained two individuals and the other two populations contained only one individual each (Leigh et al. 1984).

In 1994, surveys indicated that there had been a severe decline in the known populations, however, several new populations were found (Threatened Species Unit 1998b). In 1994, the species total known abundance was 86 individuals, across 10 populations (one surviving population and nine new populations) (Barker 1996). The size of each individual population varied from 1—32 plants. The largest population of 32 plants was infected with the dieback fungal pathogen, Phytophthora cinnamomi (Barker 1996). In 1999, there was a mass germination event of approximately 1000 seedlings had occurred at the Barnes Hill population (population ID 5) (Potts & Barker 1999).

The 2001-2005 Recovery Plan for the Shy Susan identified seven populations, separated from each other by at least 300 m. Two of the seven populations are each made up of two subpopulations (separated by approximately 100 m) (Potts & Barker 1999). By 2005, the population at Barnes Hill had declined to 173 plants, indicating that mass germination is not a guarantee of high recruitment success. In 2007, the Barnes Hill population had declined further to 49 plants (North Barker Ecosystem Services 2008).

Based on surveys carried out in 2005 and 2007 across the species’ known populations (North Barker Ecosystem Services 2008):

there may still be substantial soil seed banks within the range of the Shy Susan;populations that produced such seed banks were probably much larger than any current populations;the trigger for germination is not well-understood; andthe seed bank may be depleted without the establishment of a replacement cohort.

Population sizes for the Shy Susan in 1996, 2005 and 2007 are shown in the table below (Barker 1996; North Barker Ecosystem Services 2008). The total known population size in 2007 was estimated to be 222 plants across eleven populations:

  Population Size
Population ID 1996 2005 2007
1 6 4 5
2 7
3 33 6 20
4 3 0 0
5 2 148 49
6 15 11 5
7 3 Unknown Unknown
8 1 Unknown Unknown
9 16 7 7
10 1 4 23
11 NA NA 113

The 24 individuals discovered in 1985 all occurred in state forest (Brown et al. 1986). However, in 1994, the majority of populations appeared to occur on private land (Barker 1996). There were discrepancies between sources on the number of populations which occurred on protected land and those on private property (Barker 1996; Commonwealth of Australia 1999d; Johnson & Barker 1998). In 1999, it was reported that most populations were in the process of being protected, either via acquisition of private land under the 1999 regional Forest Agreement Private Land Reserve Program, or designation as forest reserves (Potts & Barker 1999).

The serpentine rock geology, which the species is known to associate strongly with, occupies 530 ha in the region the species occurs in; of which, 270 ha (51%) occurs in state forest, 220 ha (41%) is privately owned and 40 ha (8%) is crown water reserve (Brown et al. 1986).

The Shy Susan is essentially restricted to serpentine geology (Brown et al.1986; Johnson & Barker 1998; Potts & Barker 1999; Thompson 1976; Threatened Species Unit 1998), but may occur on substrates overlying other types of low-silica (ultramafic) rocks (Leigh & Briggs 1992). The species grows in shallow soils, on gently sloping hillsides of easterly or south-easterly aspect (Brown et al. 1986). The species is also associated with outcrops and relatively open habitat which are more floristically diverse than other superficially similar habitat (Barker 1996; Potts & Barker 1999; Threatened Species Unit 1998b).

The species mainly occurs in heathy Black Peppermint (Eucalyptus amygdalina) dry sclerophyll forest and woodland, with occasional Swamp Gum (E. ovata) (Brown et al. 1986; Leigh & Briggs 1992; Potts & Barker 1999) and also in shrubby Eucalyptus amgydalina/Australian Oak (E.obliqua) forest (Johnson & Barker 1998). In heathy E. amygdalina-dominated communities, a shrubby mid-storey of Allocasuarina littoralis and Banksia marginata occur sparsely over a dense, heathy understorey dominated by Lomandra longifolia, Correa reflexa, Hibbertia riparia, Baeckea ramosissima, Gahnia spp. and grasses.

The species is closely associated with two other range restricted, Tasmanian endemic plants strongly associated with serpentine geology; Epacris virgata and Spyridium obcordatum (Brown et al.1986; Leigh & Briggs 1992; Potts & Barker 1999). There are some exceptions to these vegetation associations, for example, the Barnes Hill population occurs in Allocasuarina littoralis-dominated woodland, largely devoid of an understorey (Potts & Barker 1999).

Habitat critical to the survival of the Shy Susan is not identified in the National Recovery Plan for the Shy Susan, however, due to the critically endangered status of the species and small, fluctuating populations, any site with known presence is habitat critical to the survival. In addition, any site where the species is not previously known, but is discovered through surveys or other means, is also considered habitat critical to the survival.

The Shy Susan generally produces an abundance of 10—11 mm pale lilac to deep pink-purple flowers during September to early December each year. Although the species is monoecious (flowers are bisexual) the species requires cross-pollination in order to successfully produce fruit and seeds (plants cannot self-pollinate) (Potts & Barker 1999). Native bees are thought to be the key pollinator for the species and low conversion rates of flowers to fruits are potentially due to low numbers of, or absence of, pollinators (Hingston & McQuillan 1998; Hingston 1999 cited in Potts & Barker 1999). Failure to attract pollinators or to achieve pollination may also be due to the distance between populations and the low numbers of plants in smaller populations. Research on other species of the Tetratheca genus indicates that the majority of pollen is transported less than 10 m by pollinators (Bell pers. comm. cited in North Barker Ecosystem Services 2008).

Fruits are green or purple locular capsules, 4 mm long and 2.5—3 mm wide, with a uniform, but sparse, covering of gland-tipped hairs (Potts & Barker 1999). Fruits disperse seeds when they dehisce (split open) at maturity. Seeds are brown, 3 mm long, oblong and have a pale appendage, which is thought to attract insects to transport the seed prior to consuming the appendage (Potts & Barker 1999).

Seeds are thought to remain viable in the soil for at least 10—20 years, however, some populations do not have a seed bank, which may be due to an extended period of poor seed production (Potts & Barker 1999). The germination trigger for seeds is not well-known (Johnson & Barker 1998). Ground or canopy disturbance, fire and aging have been proposed as stimulants for germination (Barker 1996; Potts & Barker 1999). Plant longevity has been estimated to be at least 10 years.

Although Tetratheca gunnii closely resembles other Tetratheca species, T. gunnii can generally be distinguished by its smaller leaves and flowers (Kirkpatrick 2000).

As the Shy Susan’s ecology is not clearly understood, the reasons for the species’ decline are not clear. A number of potential threats have been suggested, such as:

  • susceptibility to the Phytophthora cinnamomi dieback disease and subsequent mortality;
  • destruction and fragmentation of habitat, especially in areas which are not protected land tenures (mining and timber harvesting are thought to be major causes of habitat loss) (Threatened Species Unit 1998b);
  • degradation of habitat due to grazing on private land and state forests;
  • overcollecting of specimens (more likely a historical threat) (Brown et al. 1986);
  • inappropriate fire regimes, which may kill adults before first seed-set (if too frequent) or may not stimulate seed germination on a regular basis (if not frequent enough); and
  • inbreeding depression, particularly in small populations (Barker 1996).

A number of actions have been undertaken as part of the implementation of the National Recovery Plan for the Shy Susan. The first was the implementation of an intense broad-scale fire in an attempt to stimulate regeneration from any existing seed bank. The results of the trial on one known population that was burnt indicated that about 6 of the existing 13 plants resprouted from root stock, but no new plants were identified. After the burning experiment, a fence was erected around this population to protect it from grazing by livestock.

Documents relevant to the management of the Shy Susan can be found at the start of the profile.

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
Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Commonwealth Listing Advice on Tetratheca gunnii (Shy Susan) (Threatened Species Scientific Committee, 2001bp) [Listing Advice].
Agriculture and Aquaculture:Livestock Farming and Grazing:Grazing pressures and associated habitat changes Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Biological Resource Use:Logging and Wood Harvesting:Habitat disturbance due to foresty activities Listing Statement Shy Susan Tetratheca gunnii (Threatened Species Unit, 1998b) [Information Sheet].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Loss and/or fragmentation of habitat and/or subpopulations Commonwealth Listing Advice on Tetratheca gunnii (Shy Susan) (Threatened Species Scientific Committee, 2001bp) [Listing Advice].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) Commonwealth Listing Advice on Tetratheca gunnii (Shy Susan) (Threatened Species Scientific Committee, 2001bp) [Listing Advice].
Energy Production and Mining:Mining and Quarrying:Habitat destruction, disturbance and/or modification due to mining activities Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Human Intrusions and Disturbance:Recreational Activities:Disturbance, especially from human recreational activities and development Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation Oryctolagus cuniculus (Rabbit, European Rabbit) Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Vegetation and habitat loss caused by dieback Phytophthora cinnamomi Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Commonwealth Listing Advice on Tetratheca gunnii (Shy Susan) (Threatened Species Scientific Committee, 2001bp) [Listing Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Natural System Modifications:Fire and Fire Suppression:Inappropriate prescribed regimes and/or vegetation management to control fire regimes Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Species Stresses:Indirect Species Effects:Low numbers of individuals Tetratheca gunnii Recovery Plan 2001-2005 (Potts, W. C. & Barker, P., 1999) [Recovery Plan].
Commonwealth Listing Advice on Tetratheca gunnii (Shy Susan) (Threatened Species Scientific Committee, 2001bp) [Listing Advice].

Barker, P C J (1996a). Extension surveys and long term monitoring plots for selected species threatened by Phytophthora cinnamomi in Tasmania. Forestry Tas. & Aust. Nature Conservation Agency.

Barker, P. (1996). Selecting Viable Populations of Threatened Plants for Conservation Management. Hobart: Tasmanian Parks & Willdife.

Brown, M J, Bayly-Stark, H J, Duncan, F and Gibson, N (1986). Tetratheca gunnii Hook. F. on serpentine soils near Beaconsfield, Tasmania. Papers & Proceedings Royal Society of Tas. 120:33-38.

Commonwealth of Australia (CoA) (1999d). Tasmania-Commonwealth Regional Forest Agreement: Summary of Life history and population dynamics for vascular forest flora. [Online]. Available from: http://www.rfa.gov.au/rfa/tas/raa/envher/volumes1-4/fl_index.html.

Council of Heads of Australian Botanic Gardens (CHABG) (1994). Census of plants in botanic gardens. [Online]. Canberra: Australian National Botanic Gardens. Available from: http://www.anbg.gov.au/chabg/census/census.html.

Department of the Environment (2014a). Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi. [Online]. Canberra; ACT: Department of the Environment. Available from: http://www.environment.gov.au/resource/threat-abatement-plan-disease-natural-ecosystems-caused-phytophthora-cinnamomi.

Department of the Environment, Water, Heritage and the Arts (DEWHA) (2009w). Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi. [Online]. Canberra; ACT: Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/tap/phytophthora.html.

Hingston, A.B. & P.B. McQuillan (1998). Does the recently introduced bumblebee Bombus terrestris (Apidae) threaten Australian ecosystems?. Australian Journal of Ecology. 23:539-49.

Johnson, K.A. & P.J.C. Barker (1998). Management Prescriptions for Threatened Species on Public Land. Hobart, Tasmania: Forestry Tasmania.

Kirkpatrick, J. (2000). Threatened Flora -plants listed as extinct, endangered or vulnerable. [Online]. Created by Bushcare Technical Extension (Tasmania). Available from: http://www.bushcare.tas.gov.au/info/.

Leigh, J., R. Boden & J. Briggs (1984). Extinct and Endangered Plants of Australia. Melbourne, Victoria: Macmillan.

Leigh, J.H. & J.D. Briggs (Eds) (1992). Threatened Australian Plants. Overview and Case Studies. New South Wales National Parks and Wildlife Service.

North Barker Ecosystem Services (2008). Barnes Hill and Mt Vulcan - Botanical Survey and Fauna Habitat Assessment.

Potts, W. C. & Barker, P. (1999). Tetratheca gunnii Recovery Plan 2001-2005. [Online]. Dept of Primary Industries & Water. Hobart, Dept of Primary Industries & Water. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/t-gunnii/index.html.

Thompson, J. (1976). A Revision of the genus Tetratheca (Tremandraceae). Telopea. 1(3):139-215.

Threatened Species Section (TSS) (2013b). Tetratheca gunnii (shy pinkbells): Species Management Profile for Tasmania's Threatened Species Link . [Online]. Available from: http://www.threatenedspecieslink.tas.gov.au/tetratheca-gunnii.

Threatened Species Unit (1998b). Listing Statement Shy Susan Tetratheca gunnii. [Online]. Parks and Wildlife Service, Tas. Available from: http://www.dpiw.tas.gov.au/inter.nsf/Attachments/SROS-6VJURQ/$FILE/Tetratheca%20gunnii%20listing%20statement.pdf.

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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). Tetratheca gunnii in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Wed, 3 Sep 2014 06:00:30 +1000.