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
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 Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
 
Policy Statements and Guidelines Draft survey guidelines for Australia's threatened orchids (Department of the Environment, 2013b) [Admin Guideline].
 
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 Esperance District (Craig, G.F. & D.J. Coates, 2001) [State Species Management Plan].
WA:Declared Rare and Poorly Known Flora in the Narrogin District (Durell, G.S. & R.M. Buehrig, 2001) [State Species Management Plan].
State Listing Status
WA: Listed as Critically Endangered (Wildlife Conservation Act 1950 (Western Australia): September 2013 list)
Scientific name Rhizanthella gardneri [20109]
Family Orchidaceae:Orchidales:Liliopsida:Magnoliophyta:Plantae
Species author R.Rogers
Infraspecies author  
Reference Journal of the Royal Society of Western Australia 15 (17Oct. 1928) 1, t. I, II.
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: Rhizanthella gardneri

Common name: Underground Orchid

The Underground Orchid's closest relative is the Eastern Underground Orchid (Rhizanthella slateri), which occurs on the east coast of Australia (Rye et al. 1982).

The Underground Orchid is a succulent, subterranean orchid (Brown et al. 1998; Rye et al. 1982). The species is dependant on a mycohrrizal symbiosis (fungal relationship), and occurs within Broom Bush (Melaleuca uncinata) shrubland (Mursidawati 2004).

Flowering of the Underground Orchid begins in late May to early June when each plant produces up to 100 small, inward facing, cream to reddish coloured flowers, surrounded by 6–12 large, cream or pinkish-cream bracts (Brown et al. 2003). These bracts form a tulip-like head that curves over the flowers forming a small opening at the soil surface (Brown et al. 2003). A layer of leaf and bark litter covers this opening (Brown et al. 2003). The plants have a horizontal rhizome 6–12 cm below the ground level, which, like the rest of the plant, is succulent and produces a formalin-like odour when cut (Brown et al. 2003). Once pollinated, each flower produces a berry-like indehiscent fleshy fruit containing 20–150 seeds (Brown et al. 2003). This type of fruit is unique amongst the Western Australian orchids as species in all other orchid genera produce a dehiscing pod from which thousands of minute seeds are dispersed by the wind (Brown et al. 2003).

The Underground Orchid is known from six sites at two disjunct areas 300 km apart in the Western Australia wheatbelt. The first area is in the central wheatbelt between Corrigin and Babakin and the second is north-west of Munglinup (Brown et al. 2003). The following table presents distribution information for the Underground Orchid (Brown et al. 2003; Brundrett 2011):

Population number Location Tenure Survey year Number of plants Condition Notes 
1 Babakin Nature Reserve 1980
1981
1993
2001
2002
2006
2009
1
110
0
15
10
14
5

Poor

 

2 Sorenson's Reserve, west of Babakin Nature Reserve  1981
2001
2002
2006
2009
4
6
2
10
0
Good The reserve has a total area of 108 ha (Dixon & Pate, 1984).
3 Oldfield River Unvested Crown Land 1982
2002
2004
2010
4
2
26
1
Good The site has been described as pristine and unspoilt (Carstairs & Coates 1994).
4 Cheadanup Reserve, north-west of Munglinup  Nature Reserve 1981
1982
2002
2004
2008
6
4
0
23
25
Not seen The reserve covers an area of more than 6800 ha (Carstairs & Coates 1994). Vacant crown land with pristine bushland extends north-west from the reserve, but otherwise all other margins of the reserve are bordered by agricultural lands (Carstairs & Coates 1994). Sites with highest underground orchid potential, occur within 2 km of a southern boundary road (Dixon & Pate 1984).
5 North-west of Munglinup  Private 1979
1981
2002
15
10
2

Good

Population described as occurring over a small portion of uncleared land in a paddock (George 1980). The paddock was mistakenly scrub rolled in 1979 (George 1980).
6 Kunjin Townsite Reserve

1989
2001
2002
2006
2009

38
2
3
5
11
Poor The reserve is small (Carstairs & Coates 1994).

Formerly, the Underground Orchid may have been widespread between Corrigin and Wubin with previous collections having been made from Goomalling, Shackleton and Moonigin (Brown et al. 1998; Dixon & Pate 1984; Hoffman & Brown 1992; Leigh & Briggs 1992; Rye et al. 1982). Although most of the land between known Underground Orchid sites has been developed for agriculture, undiscovered populations may still exist.

The Underground Orchid is estimated to have less than 50 plants in total (Brown et al. 2003), although this may be an underestimate since flowering plants are hard to detect and the ratio between flowering and non-flowering plants is unknown (Brundrett 2011). Intensive surveys at known sites in 2001–02 found 27 plants in total (Brown et al. 2003).

The Underground Orchid is saprophitic (relying on the reduction of organic matter for nutrition). The species grows in association with Broom Bush often in association with decaying stumps. Broom Bush often forms dense thickets. Scattered, emergent Eucalyptus and Acacia species are usually present (Brown et al. 1998; Carstairs & Coates 1994; Dixon & Pate 1984; Hoffman & Brown 1992; Leigh & Briggs 1992).

Soils are generally sandy-clay to sandy-loam over white clay with a gritty texture and bleached white to grey colour (Brown et al. 1998; Carstairs & Coates 1994; Dixon & Pate 1984; Hoffman & Brown 1992; Leigh & Briggs 1992). One site includes an underlying clay base at approximately 20 cm or more (Dixon & Pate 1984).

The presence of a specific fungus (Bougoure et al. 2010) may be defining habitat requirement.

Reproduction

The Underground Orchid flowers between May and July. The flowers are self compatible but do not appear to autofertilize. The main pollinating agent is unknown, but tiny wasps, gnats, ants and termites have occasionally been seen visiting the plants (Brown et al. 1998; Carstairs & Coates 1994). It is possible that the succulent fruit is eaten by small marsupials and the seeds passed out in their faeces (Hoffman & Brown 1998). Seeds mature in November and December but seed set appears to be low (Rye et al. 1982).

Rhizomes of the Underground Orchid are capable of vegetative division, so it is likely that plants located with a few metres are the same individual or closely related (Brundrett 2011). Consequently, a population genetics study is required to determine the size of individuals of this species and the number present at each location (Brundrett 2011).

Mycorrhizae

The mycorrhizal fungus utilised by the Underground Orchid has been morphologically identified as Thanatephorus gardneri, although further investigations suggest that the fungus is from the Ceratobasidium genus (Bougoure et al. 2009). 

Reliance on the mycorrhizal fungus, and the association with Broom Bush, may help clarify the distribution of the Underground Orchid (Bougoure et al. 2010).

Fire ecology

The fire requirements of the Underground Orchid are not well known, but the species may react positively to some level of disturbance due to the increased nutrient availability, reduced competition with surrounding vegetation and smoke induced triggers (Bougoure et al. 2008).

The Underground Orchid is confined to Broom Bush shrubland in association with Thanatephorus or Ceratobasidium fungus (Bougoure et al. 2009).

The Underground Orchid has been confused for the underground fungi Stink-horn Fungus (Clathrus puscillus) and Earthstar Fungus (Geastrum spp.) as well as a parasitic angiosperm Orobanche australiana (Dixon & Pate 1984).

The Underground Orchid is related to the Eastern Underground Orchid, a subterranean orchid occurring in eastern Australia from central-eastern NSW to south-eastern Queensland (Brown et al. 2003; Rye et al. 1982).

Current threats

The following table describes the threats affecting the Underground Orchid (Brown et al. 2003):

Threat Description
Habitat clearing There is a lack of suitable habitat, and this is a barrier to more populations being found. The lack of suitable habitat also limits the number of areas suitable for translocation.

Habitat degradation (including salinity, weed invasion and soil compaction)

Degraded habitat is a current and continuing threat. Thickets of Broom Bush, that the Underground Orchid depends for its fungal nutrient link, are dying back from the edges due to drought and possibly rising saline water tables.

Rising saline water tables are possibly already causing deaths amongst the associated Broom Bush and are likely to become an increasing future threat.

Weed invasion is a minor threat to all populations. The effect of weeds is uncertain but they are likely to compete for soil moisture and nutrients needed by the orchid and associated fungi. Weeds also increase the fire hazard due to the easy ignition of high fuel loads produced annually by many grass weed species. Weed species including Briza spp., Capeweed (Arctotheca calendula), Wild Turnip (Rhaphanus raphanistrum) and Trifolium spp. have been recorded at one site (Carstairs & Coates 1994; Durell & Buehrig 2001).

Soil compaction, due to poor levels of leaf and bark litter and human disturbance, has resulted in poor flowering and possible deaths of Underground Orchid plants.

Drought Drought appears to be a major threat to the habitat of the Underground Orchid in the central Wheatbelt.
Infrastructure maintenance Road and firebreak maintenance threatens several southern populations.
Inappropriate fire regimes Inappropriate fire may threaten populations if it occurs during the flowering period of the orchid, and overly frequent fires are likely to alter its habitat. One southern population was burnt some years ago and, despite several searches since then, no Underground Orchid plants have been located.
Human substrate disturbance Human damage during searches for the orchid is a continuing threat. The method used to locate plants is quite destructive requiring the removal of leaf litter beneath Broom Bush. This litter is often not replaced and when it is, is usually mixed with soil resulting in soil compaction and the drying out of the area where the orchid occurs.

Poor recruitment

Poor recruitment and declining populations are a major threat to the orchid. In areas where many flowering plants were located, during surveys in the 1980s, few plants were found during surveys in 2001 and 2002.

A lack of a seed dispersal agent and severe habitat fragmentation may prevent recruitment into new habitats.

Population threat summary

Brown and colleagues (2003) summarised the Underground Orchid population threats. This summary is presented below:

Population number Location  Threats
1 Babakin Drought, soil compaction, future rising saline water tables, degraded habitat and habitat damage during searches.
2 Sorenson's Reserve, west of Babakin Drought, soil compaction, future rising saline water tables, lack of habitat, habitat damage during searches and stochastic events due to small reserve size.
3 Oldfield River Drought, road and firebreak maintenance and habitat damage during searches.
4 Cheadanup Reserve, north-west of Munglinup  Drought, inappropriate fire and firebreak maintenance.
5 North-west of Munglinup  Drought, weeds, clearing (the population occurs on private property) and firebreak maintenance.
6 Kunjin Drought, soil compaction, degraded habitat, future rising saline water tables, habitat damage during searches and stochastic events due to small reserve size.

Underground Orchid Recovery Plan

The Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan (Brown et al. 2003) details priority recovery actions for the Underground Orchid. Below are the actions in the plan, see the plan for further details (Brown et al. 2003):

  • coordinate recovery actions
  • liaise with land managers to achieve long-term protection of habitat
  • monitor populations
  • collect seed and mycorrhizal fungi from all populations and develop suitable long-term storage protocols
  • obtain biological and ecological information
  • research population genetics
  • undertake in situ seed germination
  • conduct further surveys
  • develop and implement a translocation project
  • conduct habitat degradation research
  • develop and implement a fire management strategy
  • undertake weed control
  • rehabilitate habitat
  • promote awareness
  • review the need for a full Recovery Plan and update if necessary.

Recovery action implementation

The Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan (Brown et al. 2003) details actions that have already been implemented for the Underground Orchid and include:

  • All relevant land owners and managers have been made aware of the location and threatened status of the taxon.
  • Staff from the Botanic Garden and Parks Authority (BGPA), and the Department of Environment and Conservation's (DEC) Narrogin and Esperance Districts and Threatened Species and Communities Unit regularly monitor populations of the Underground Orchid.
  • The Narrogin and Esperance District Threatened Flora Recovery Teams are overseeing the recovery of this species and will include information on progress in annual reports to the DECs Corporate Executive and funding bodies.
  • Two reserves at Babakin have now been vested in the Conservation Commission as Class A Nature Reserves for the Conservation of Flora and Fauna.
  • A masters student from the University of Western Australia has commenced DNA extraction from floral bracts and fungal isolates collected during 2001 season by staff from the BGPA.
  • The BGPA currently has limited seed collections of Underground Orchid and the associated Melaleuca uncinata.
  • Mycorrhizal fungi have been isolated from a section of rhizome from the Babakin population. Germination tests were commenced in May 2002. However, results on fungal efficacy are unknown at this point.
  • The BGPA have developed methods for the production of mycorrhizal inoculum suitable for glasshouse and field studies.
  • Surveys of all known populations were undertaken by DEC and BGPA staff in 2002.

Brundrett (2011) identifies further work underken on the recovery of the species. Further actions include:

  • expert contribution to nature reserve proposals (Brundrett 2011)
  • regular monitoring (Brundrett 2011)
  • permanent plots established (Bougoure et al. 2008)
  • nutritional (Bougoure et al. 2008), genetic (Delannoy et al. 2011), in situ germination (Bougoure 2008), habitat (Bougoure et al. 2008) and seed (Brundrett 2011) research
  • critical habitat areas mapped (Brundrett 2011)
  • major issues that require action identified (Brundrett 2011).

Management documents for the Underground Orchid include:

  • Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan (Brown et al. 2003)
  • Declared Rare and Poorly Known Flora in the Narrogin District (Durrell & Buehrig 2001)
  • Declared Rare and Poorly Known Flora in the Esperance District (Craig & Coates 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
Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Climate Change and Severe Weather:Droughts:Drought Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Loss and/or fragmentation of habitat and/or subpopulations Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Human Intrusions and Disturbance:Work and Other Activities:Disturbance through scientific research Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Natural System Modifications:Other Ecosystem Modifications:Changes in hydrology leading to rising water tables and dryland salinity Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Species Stresses:Indirect Species Effects:Low numbers of individuals Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Species Stresses:Indirect Species Effects:Poor recruitment (regeneration) and declining population numbers Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].
Transportation and Service Corridors:Transportation and Service Corridors:Road and rail maintenance works Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008 (Brown, A., A. Batty, M. Brundrett & K. Dixon, 2003) [Recovery Plan].

Anonymous (2011). Rare orchid holds secrets. Countryman. Page(s) 39. Newspaper article. 17 February 2011.

Bougoure, J., M. Ludwig, M. Brundrett & P. Grierson (2009). Identity and specificity of the fungi forming mycorrhizas with the rare mycoheterotrophic orchid Rhizanthella gardneri. Mycological Research. 113(10):1097-106.

Bougoure, J., M.C. Brundrett, A. Brown & P.F. Grierson (2008). Habitat characteristics of the rare underground orchid Rhizanthella gardneri. Australian Journal of Botany. 55(6):501-511.

Bougoure, J.J. (2008). The role of mycorrhizal fungi in nutrient supply and habitat specificity of the rare mycoheterotrophic underground orchid, Rhizanthella gardneri. [Online]. Ph.D. Thesis. University of Western Australia. Available from: http://theses.library.uwa.edu.au.

Bougoure, J.J., M.C. Brundrett & P.F. Grierson (2010). Carbon and nitrogen supply to the underground orchid, Rhizanthella gardneri. New Phytologist. 186(4):947-56.

Brown, A., A. Batty, M. Brundrett & K. Dixon (2003). Underground Orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/r-gardneri/index.html.

Brown, A., C. Thomson-Dans & N. Marchant, eds. (1998). Western Australia's Threatened Flora. Como, Western Australia: Department of Conservation and Land Management.

Brundrett, M. (2011). Population Survey Data for Southern Populations of the Western Underground Orchid (Rhizanthella gardneri). Wheatbelt Orchid Rescue Project. Final Report 6. Wheatbelt Orchid Rescue Project. University of Western Australia.

Carstairs, S. & D. Coates (1994). Conservation Genetics and Population Ecology of Five Rare and Threatened Western Australian Orchids. Endangered Species Unit, Australian Nature Conservation Agency.

Craig, G.F. & D.J. Coates (2001). Declared rare and Poorly Known Flora in the Esperance District. [Online]. WA CALM. Available from: http://www.dpaw.wa.gov.au/plants-and-animals/threatened-species-and-communities/threatened-plants.

Delannoy, E., S. Fuji, C.C. des Francs, M. Brundrett & I. Small (2011). Rampant gene loss in the underground orchid Rhizanthella gardneri highlights evolutionary constraints on plastid genomes. Molecular Biology and Evolution. Published online.

Durell, G.S. & R.M. Buehrig (2001). Declared Rare and Poorly Known Flora in the Narrogin 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.

George, A.S. (1980). Rhizanthella gardneri R.S.Rogers - The underground orchid of Western Australia. American Orchid Society Bulletin. 49:631-646.

Hoffman, N. & A. Brown (1992). Orchids of South-west Australia 2nd edn. Nedlands, Western Australia: University of Western Australia Press.

Hoffman, N. & A. Brown (1998). Orchids of South-west Australia Rev. 2nd edn. Nedlands, Western Australia: University of Western Australia Press.

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

Mursidawati, S. (2004). Mycorrizhal association, propagation and conservation of the myco-heterotrophic orchid Rhizenthella gardneri. M.Sc. Thesis. Perth: University of Western Australia.

Rye, B.L., S.D. Hopper & K.W. Dixon (1982). Underground Orchid, Rhizanthella gardneri Rogers (ORCHIDACEAE). Rare Western Australian Plants. 8. Western Australia: Department of Fisheries and Wildlife.

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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). Rhizanthella gardneri in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 22 Aug 2014 06:51:30 +1000.