Western Underground Orchid  |  

Rhizanthella gardneri

Status: Critically Endangered on the EPBC Act list

Underground Orchid 

The Underground Orchid is a succulent, subterranean orchid. The species is dependant on a mycohrrizal symbiosis, and occurs within Broom Bush shrubland .

Government evidence of impact of climate change:

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  • Australian Government, Conservation Advice, Rhizanthella gardneri

    The seed dispersal agent is currently unknown; but it is thought that small marsupials may eat the succulent fruits produced by the plant and deposit seed in their faeces. (b) Continuing decline observed and projected (iii) Ongoing threats to habitat quality from drying climate and subsequent effects on associated habitat; and from competition from invasive weeds; damage and disturbance to individuals of the species by rabbits; and inappropriate fire regimes.

    Specify if the threat is past; current or whole species or specific the conservation of the potential) subpopulations) species) Drying climate and subsequent effects on habitat.

    Climate change modelling for the south west predicts a decline in rainfall; and some seasonal shift to summer rainfall events; which is likely to increase the potential impact of drought on the species.

    Past; current and future Altered fire regimes Whole population Severe Likely to alter the habitat of the species.

    Past experiences suggest that extreme high fire intensities may result in a major change in vegetation structure and be catastrophic for R. gardneri survival.

    They also increase the fire hazard due to the easy ignition of high fuel loads; which are produced annually by many grass weed species.

    Monitoring and surveys have been carried out to determine plant numbers and impact of threats Protecting the sites from fire unless required for ecological reasons; and implemented early intervention in any wildfires which may threaten the site Surveying for additional subpopulations Vesting of two reserves near Babakin; containing subpopulations of Rhizanthella gardneri; with the Conservation and Parks Commission as nature reserves Examination of genetic variation by Botanical Gardens and Parks Authority (BGPA) using a non destructive sampling technique for DNA extraction from floral bract material collected in 2001 Isolation of mycorrhizal fungi by BGPA from sections of rhizomes by to inoculate Melaleuca scalena hosts ex situ and have enabled the germination and subsequent development of Rhizanthella gardneri rhizomes in glasshouse pot culture Collection of seed from Subpopulations 1 and 2 in 2003 for storage at BGPA.

    It is likely that drought also has indirect impacts on underground orchids due to reduced productivity of the host plants and their associated fungus and or through loss of litter from the soil surface.