Underground orchid (Rhizanthella gardneri) Interim Recovery Plan 2003-2008

Interim recovery plan no. 127
Andrew Brown, Andrew Batty, Mark Brundrett & Kingsley Dixon
Department of Conservation and Land Management, WA, 2003

Summary

Scientific Name: Rhizanthella gardneri Common Name: Underground orchid
Family: Orchidaceae Flowering Period: May to July
Dept Region: Wheatbelt Dept District: Narrogin
Shire: Corrigin Recovery Team: Narrogin District Threatened Flora Recovery Team

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, Western Australia; Dixon, K. W., J. S. Pate, et al. (1990). The Western Australian fully subterranean orchid Rhizanthella gardneri. Orchid Biology, Reviews and Perspectives, V. J. Arditti. Portland, Oregon, Timber Press. 5: 37-62; Warcup, J. H. (1985). Rhizanthella gardneri (Orchidaceae), its Rhizoctonia endophyte and close association with Melaleuca uncinata (Myrtaceae) in Western Australia. New Phytologist 99: 273-280; Warcup, J. H. (1991). The Rhizoctonia endophytes of Rhizanthella (Orchidaceae). Mycological Research 95: 656-659.

Current status: Rhizanthella gardneri was declared as Rare Flora in November 1980 and currently (2002) meets World Conservation Union (IUCN, 2000) Red List Category 'CR' under criteria B2ab(ii,iii,v); C2a(i); D due to the extreme fragmentation of populations, a continuing decline in area of occupancy, area, extent, quality of habitat and the number of mature individuals and a total population size of less than 50 mature individuals. The main threats are the death of adult plants, poor recruitment, loss of habitat (due to the death of the associated Melaleuca uncinata), human damage when searching for plants, drought and weeds.

Critical habitat: The critical habitat for Rhizanthella gardneri comprises the area of occupancy of the known populations; similar habitat within 200 metres of known populations; and additional nearby occurrences of similar habitat that do not currently contain the taxon but may have done so in the past and may be suitable for future translocations.

Habitat critical to the survival of the species, and important populations: Given that this species is listed as Critically Endangered it is considered that all known habitat for wild and translocated populations is habitat critical.

Benefits to other species/ecological communities: There are no ecological communities or other threatened species in the immediate vicinity of Rhizanthella gardneri. However, recovery actions implemented to improve the quality or security of the habitat of the species, such as weed control and rehabilitation, will benefit the habitat in which it occurs.

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. However, as Rhizanthella gardneri is not listed under any international agreement, the implementation of other international environmental responsibilities is not affected by this plan.

Role and interests of indigenous people: There are no known indigenous communities interested or involved in the management of areas affected by this plan. Therefore no role has been identified for indigenous communities in the recovery of this species.

Social and economic impacts: The implementation of this recovery plan is unlikely to cause significant adverse social and economic impacts. One population of Rhizanthella gardneri occurs on private property. However, negotiations between relevant parties have ensured that the area directly supporting the species will be left uncleared.

Evaluation of the Plans Performance: The Department of Conservation and Land Management, in conjunction with the Recovery Team will evaluate the performance of this IRP. In addition to annual reporting on progress with listed actions and comparison against the criteria for success and failure, the plan is to be reviewed within five years of its implementation.

Habitat requirements: Rhizanthella gardneri is currently known from two disjunct areas some 260 km apart (The Munglinup - Oldfield River area in the south-eastern Wheatbelt and the Corrigin - Babakin area in the Central Wheatbelt (Brown et al. 1998)). In both areas it grows in association with Melaleuca uncinata and specific micorrhizal fungi forming a three-way relationship. Habitat is mallee heath.

Existing Recovery Actions: The following recovery actions have been or are currently being implemented -

  1. All relevant land owners and managers have been made aware of the location and threatened status of the taxon.
  2. Staff from the Botanic Garden and Parks Authority (BGPA), and the Department's Narrogin and Esperance Districts and Threatened Species and Communities Unit regularly monitor populations of the taxon.
  3. 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 Department's Corporate Executive and funding bodies.
  4. Two reserves at Babakin have now been vested in the Conservation Commission as Class A Nature reserves for the Conservation of Flora and Fauna.
  5. 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.
  6. The BGPA currently have limited seed collections of Rhizanthella gardneri 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.
  7. The BGPA have developed methods for the production of mycorrhizal inoculum suitable for glasshouse and field studies.
  8. Surveys of all known populations were undertaken by departmental and BGPA staff in 2002.

IRP Objective: The objective of this Interim Recovery Plan is to abate identified threats and maintain or enhance in situ populations to ensure the long-term preservation of the taxon in the wild.

Recovery criteria
Criteria for success: The number of individuals within populations and/or the number of populations have increased by 10% or more.
Criteria for failure: The number of individuals within populations and/or the number of populations have decreased by 10% or more.

Recovery actions
1. Coordinate recovery actions 1. Develop and implement a translocation proposal.
2. Liase with land managers and achieve long-term protection of habitat. 2. Conduct research into the reasons for habitat degradation.
3. Monitor populations. 3. Develop and implement a fire management strategy.
4. Collect seed and mycorrhizal fungi from all populations and develop suitable long-term storage protocols. 4. Undertake weed control.
5. Obtain biological and ecological information. 5. Rehabilitate habitat.
6. Population genetics 6. Promote awareness.
7. In situ seed germination. 7. Review the need for a full Recovery Plan and prepare if necessary.
8. Conduct further surveys.