Caladenia leucochila

Future mining operations
Subpopulations within the Muja South Public Environmental Review (PER) footprint are subject to potential future mining. Clearing of vegetation for access tracks, power lines and other linear infrastructure corridors is also a threat. A drilling programme covering 32.67 hectares has also been proposed.

Altered fire regimes
Prescribed burning during winter and spring, when the leaf is present and the new tuber is being formed, may kill plants.

Timber extraction
This is a potential threat to Caladenia leucochila as it would significantly alter vegetation structure, opening the forest canopy and changing the moisture level of the soil surface.

Drought
Poor winter rainfall is believed to coincide with a reduction of flowering plants.

Hydrological changes
Changed hydrology due to mining has the potential to aversely alter the orchids’ habitat.

Small subpopulation size
Caladenia leucochila is known from mostly small subpopulations, many of which may be impacted by lack of recruitment and chance demographic or environmental events.

Grazing
Although grazing does not appear to kill plants it reduces the reproductive output of the species if flowers or fruiting capsules are eaten.

Road maintenance
Threats to a road verge subpopulation include grading, chemical spraying, construction of drainage channels and the mowing of roadside vegetation.

Weeds
Weeds suppress early plant growth by competing for soil moisture, nutrients and light, and also increase the potential fire hazard due to higher fuel loads.

This species is listed as Endangered under the Australian Government Environment Protection and Biodiversity Conservation Act 1999.

In place

• Land managers have been notified of the location and threatened status of Caladenia leucochila. Notifications detail the current Declared Rare Fauna (DRF) status of the species, the associated legal obligations in regards to its protection, and contact details for management assistance.
• Seed collected from C. leucochila by Botanic Gardens and Parks Authority (BGPA) in 2008, and between 2010 and 2012, is currently stored in their orchid seed bank. Some seed was successfully germinated in 2012 and 550 seedlings have been potted out in the orchid glasshouse at BGPA. Collar slivers were collected between 2010 and 2012 and associated fungi were isolated, cleaned of contaminants, and stored at the BGPA fungal library.
• A draft proposal for a trial translocation of 50 C. leucochila seedlings has been developed by BGPA. The trial will be used to establish the best life history stage at which to translocate terrestrial orchids by comparing seedlings planted at the beginning of their growth phase, and dormant tubers planted during summer. Plants are to be watered during the growing season and caged to exclude macropod herbivory.
• Small portions of leaf material collected from mature C. leucochila plants by BGPA is stored in dry silica gel for future genetic analysis.
• Preliminary studies of the pollination biology of C. leucochila have been undertaken by BGPA along with studies on the distribution of the pollinator. Research has confirmed pollination by thynnid wasps by sexual deception and occasional visits by nectar foraging bees.
• Monitoring and surveys have been carried out to determine plant numbers and impact of threats.
• Caladenia leucochila is covered by the Department of Parks and Wildlife (2016) Collie Spider Orchid (Caladenia leucochila) Interim Recovery Plan 2016–2021. Interim Recovery Plan No. #. Department of Parks and Wildlife, Western Australia (in draft).

• Ongoing monitoring of subpopulations and their habitat should be undertaken to identify trends or potential management requirements.
• DRF markers are required at Subpopulation 4 and several newly discovered subpopulations to reduce the risk of accidental damage during road maintenance activities.
• When monitoring ascertains that the threat from herbivory is high, protective cages and/or fencing may be considered.
• Caladenia leucochila is thought to be killed by fire that occurs when the plant is in active growth and a fire management strategy will be developed that recommends fire frequency, intensity, seasonality, precautions to prevent bushfire and strategies for reacting to bushfire, and the need, method of construction and maintenance of firebreaks, and associated weed control measures, including actions to minimise the risk of unplanned fire.
• To guard against the extinction of natural subpopulations additional seed collections, along with samples of the orchid’s symbiotic fungus, will be made and stored at the BGPA.
• Understanding the effects of changes in the water table on vegetation associated with the orchid is required and will include monthly monitoring of groundwater and surface water.
• Areas of potential habitat be surveyed for the presence of C. leucochila during its September, October flowering period.
• Weeds are a minor threat to many subpopulations and, when deemed necessary, weed control will be implemented.
• Further research on the biology and ecology of C. leucochila may include: 

1. Identification of pollinators and their habitat requirements
2. Seed viability
3. Identification of the fungal symbiont associated with C. leucochila and its distribution in the wild
4. Conditions necessary for natural germination
5. Response to disturbance, competition, drought, inundation and grazing
6. Longevity of plants
7. Time taken to reach maturity
8. Minimum viable subpopulation size