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Metallic Sun-orchid

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Metallic Sun-orchid
Thelymitra epipactoides
Kingdom:Plantae
Division:Magnoliophyta (Angiosperm)
Class:Liliopsida (Monocotyledon)
Subclass:Liliidae
Order:Orchidales
Family:Orchidaceae
Status
World: IUCN endangered
Australia: endangered
Victoria: endangered
FFG: listed

The Metallic Sun-orchid (Thelymitra epipactoides) is one of the largest and most impressive of the Thelymitra. It grows from a subterranean tuberous root and when fully developed has a single, erect, sheathing leaf to 25cm and a flower stem to 50cm tall which contains 5-20 flowers. Flower colour is highly variable, brown, copper, blue and green being the main colour groups which are determined by the proportion of red, blue and green epidermal cells, some of which are reflective giving a metallic appearance.

Metalic sun orchid Thelymitra epipactoides 341 flowers.jpg Flower colour varies between plants

Metallic sun orchid noushka reiter341.jpg

Metallic Sun-orchid full plant 341.jpg Sheathing leaf and multiple flowers Metallic sun-orchid non flowering 341.jpg Non-flowering mature form Metallic sun-orchid in situ341.jpg Typical habitat utilising bare area under dead vegetation

Metallic sun orchid map341.jpg

Distribution of Metallic Sun-orchid in south-west Victoria. Many sites are no longer viable or in a state of decline e.g. No sightings have been seen in Mocamboro Flora Reserve or the Lower Glenelg National Park for the last five years (Pitts pers. comm.) despite extensive surveying with the Australian Native Orchid Society between 2009-2011. The plants in Port Campbell are thought to be in decline as a result of increase biomass due to inappropriate fire regimes, invasion of coast wattle and increased browsing.

Metallic sun orchid root isolation341.jpg

Digging to collect root material containing mycorrhizal fungi.

Metallic sun orchids isolating peletons341.jpg

Mycorrhizal isolates being harvested from root material. This involves isolating peletons which can be grown on sterile medium. More about how mycorrhizal fungi are used see: Orchid mycorrhizal fungi: identity and diversity of fungi from Victorian endangered orchid species

Metallic sun orchids (3 months)341.jpg

Successful growth of the first germinants of Metallic Sun-orchid, 3 months old.

Metallic sun orchids (6 months)341.jpg

Metallic Sun-orchids grown in the laboratory 6 months old.

Metallic sun orchids (12 months)341.jpg

Metallic Sun-orchids grown in the laboratory 12 months old.


A sweet scent is produced when flowers open, usually in October and only on warm sunny days with low humidity. Mature non-flowering plants produce a single, erect, linear-lanceolate leaf to 51cm tall. Immature plants produce a linear leaf to about 30cm, usually on an acute angle to the ground (Cropper et al 1989, Cropper & Calder 1989, Backhouse & Jeanes 1995).

The Metallic Sun-orchid is distributed in southern Victoria and southeastern South Australia. It was once widespread along coastal areas of Victoria from Gippsland to the far Southwest and extending inland to the Wimmera. Remaining populations are now isolated and mainly confined to parks and reserves. Apart from a few populations in the coastal areas of Gippsland such as the Gippsland Lakes Coastal Park, Blond Bay Wildlife Reserve and at Golden Beach the south-west region of Victoria contains the majority of remaining sites. Significant areas are Port Campbell National Park, Bay of Islands Coastal Park, the Tooloy-Lake Mundi Wildlife Reserve and the Kiata Flora & Fauna Reserve in the Wimmera. Population estimates vary from about 1050 plants in Australia (DEH 2006), to less than 3,000 plants (Coats et al 2002). More recent assessments suggest the population could be less than 1500 plants in the wild which comprise seven main populations in Victoria.


Contents

Habitat & ecology

Key habitat characteristics are subhumid environments where there may be a period of water stress in the summer and cool to wet winters in which soils comprising sandy loams overlying a clay subsoil have a tendency to become waterlogged.

The Metallic Sun-orchid also favours stable mature open heathland vegetation communities close to the coast where there is a mosaic of disturbed sites. These areas are often dominated by Manuka Leptospermum scoparium, Guinea-flower Hibbertia truncata, Swamp Weed Selliera radicans, Common Bog-rush Schoenus apogon and Coast Beard-heath Leucopogon parviflorus, sometimes in association with native grasses Themeda australis and Poa poifrmis. Immature plants have been observed growing around old Leptospermum stumps. The inland site near Casterton is dominated by Prickly Tea-tree Leptospermum juniperinum in association with sedgelands which provide more favourable habitat. At Kiata, open shrubland is dominated by Wattles Acacia sp. with a shrubby ground cover of Flame Heath Astroloma conostephioides. The Metallic Sun-orchid is also found in association with a mycorrhizal fungi Tulasnella asymmetrica that may assimilate nutrients for the orchid (Cropper et al 1989, Calder et al 1989).

The Metallic Sun-orchid regenerates almost exclusively from seed that falls on sites where soil or plant community disturbance has occurred. Typical examples are; opening of canopy through death of structurally dominant plants, salt induced dieback, digging by fauna such as echidnas, regular but infrequent fires, browsing and trampling by Kangaroos and Wallabies. Also minor land management activities such as track works may assist in opening up small areas, however this also comes with an added risk of introducing the spread of invasive weeds.

The Metallic-sun orchid has a dormant period between January to March, during this period the leaf and flower stem wither, this may assist the orchid in coping with events such as water stress during dry conditions and also avoid the likelihood of being damaged by fire. Generally by April a single leaf emerges, the flower stem develops in August and is fully mature during October, ( flowering can occur from September to November depending on the season and site conditions). By December the seeds are fully developed.

The flower colour and scent attract insects which provide pollination, although there is no obvious reward for pollinators as no nectar is produced. Native bees, genus Nomia are known to pollinate the Metallic Sun-orchid, in effect they are deceived by the flower’s colour and scent. The variety of flower colours within this species may also act as a means of ensuring pollinators remain attracted to the flower despite there being no nectar (Cropper & Calder 1989).

Threats

Weed invasion - including the spread of Acacia longifolia into coastal heathlands has been identified as an issue. Any form of weed invasion that smothers out light or prevents the opportunity for seed to germinate on small areas of bare ground is of concern. Weed invasion often results from disturbance to soil and vegetation, particularly where there is already a weed source in the vicinity and there is mechanical disturbance such as grading, digging etc. Weeds are often spread along walking tracks and vehicle tracks and have the potential to invade suitable orchid habitat.

Changes to soil and water regimes - this may result from road or track works or drainage of areas which can impact on the surface or sub-surface movement of water and alter the natural cycle of seasonal waterlogging and drying out of sandy loams, this being one of the habitat requirements necessary to support the Metallic Sun-orchid.

Reduced recruitment – resulting from limited seed production and impaired seed germination due to changed ecological conditions which may stem from the lack of occasional fires. Long term changes to the floristic composition of habitat can result in the loss of heathlands due to the expansion of structurally dominant species. This can alter the natural mosaic of small disturbed areas suitable for seedling development. A lack of occasional fires can also retard the floristic diversity of an area and reduce pollinators that are necessary for successful seed development. Hand pollination has been carried out with some success to overcome a lack of natural pollinators.

Grazing of flower stems - this has been identified as a major problem at times as it can severely impact on the production of seed for future recruitment of the orchid. Grazing by stock or native herbivores such as the Kangaroo and Wallaby can also cause sever browsing damage. The European Rabbit is also recognised as a problem in browsing flower stems, there are cases where the entire flowering crop of a local population has been wiped out due to rabbits (Cropper et al 1989).

Grazing by slugs - Chrysomelid Beetle lavae and Tortricid Moth lavae have been observed to graze on leaf material leading to the loss of leaf (Cropper et al 1989).

Removal by humans - apart from the fact that it is illegal to remove protected flora under the Flora & Fauna Guarantee Act, it results in the loss of plants which can impact on recruitment potential. It also assists the spread of invasive weeds into areas which can limit the viability of local populations.


Actions

Key actions necessary to maintain the viability of this species, identified by Calder et al 1989.

  • Maintain soil and water regimes
  • Provide periodic opening of the heathland canopy to create a mosaic of disturbed areas for seedling establishment through burning of small areas prior to emergence of the orchid in early March, occasional slashing may be a suitable alternative to burning.
  • Establish physical protection against browsing.


Specific Actions from the DSE Actions for Biodiversity Conservation database


Research - management and biology

  • Undertake research to identify key biological functions
  • Identify ecological correlates of key populations. Undertake assessment by conducting detailed analyses of the environmental attributes of habitats where orchids are abundant, sparse or absent. Analyse the condition of the ground layer, the role of soil physical properties and the implications for soil moisture retention.
  • Determine the effects of artificial pollination on growth, survival and reproduction.
  • Evaluate natural pollination levels and/or causes of pollinator limitation.
  • Prepare descriptions of critical, common and potential habitat using environmental and bioclimatic data. Identify environmental conditions that foster mutualistic relationships between orchids and other organisms that promote flowering, seed set and recruitment.


Population monitoring

  • Conduct annual censusing of populations. Collect demographic information such as recruitment and mortality, dormancy periods and the timing of life history stages for key populations.
  • Collate, analyse and report on census data.


Ex situ plant conservation

  • Maintain ex situ collections for display, research or insurance against losses
  • Seed has been collected from Blonde Bay, Bay of Islands Coastal Park, Lake Mundi and Kiata FFR to establish a threatened orchid seed bank and determine seed viability.
  • A mycorrihizal fungi bank has been established.


Additional actions at specific locations


Grampians National Park

  • Conduct survey: vegetation and environmental characteristics associated with key populations will be surveyed and used to document causes or potential causes of decline, identify disturbance requirements, for designing surveys for potential populations, and to prepare habitat descriptions
  • Re-stock populations with seed in autumn.
  • Cage plants to protect from grazing.


Lake Mundi

  • Control high-priority weed species.
  • Control the likelihood of accidental damage. Closure or re-routing of tracks at a number of sites will direct four wheel drive traffic away from sensitive populations. Walking tracks also need to be realigned in some cases.
  • Hand pollinate plants.
  • Prepare habitat for seedling recruitment.
  • Re-stock populations with seed in autumn.


Lower Glenelg National Park

  • Control high-priority weed species.
  • Re-stock populations with seed in autumn.
  • Prepare habitat for seedling recruitment.
  • Control the likelihood of accidental damage. Closure or re-routing of tracks at a number of sites will direct four wheel drive traffic away from sensitive populations. Walking tracks also need to be realigned in some cases.


Wilkin Flora & Fauna Reserve

  • Control high-priority weed species.
  • Control native animals to reduce grazing
  • Prepare habitat for seedling recruitment.


Port Campbell National Park

  • Prepare habitat for seedling recruitment.
  • Re-stock populations with seed in autumn.
  • Control introduced animals to reduce grazing and cage plants
  • Control high-priority weed species.


References:

  • Backhouse, G. N. and Jeanes, J. A. (1995) The Orchids of Victoria, Melbourne University Press, Carlton, Victoria.
  • Calder D.M., Cropper S.C., Tonkinson D. (1989) The ecology of Thelymitra epipactoides F. Muell. (Orchidaceae) in Victoria, Australia and the Implications for Management of the Species, Aust. J. Bot., 1989, 37, 19-32.
  • Coats F. (2003) Flora & Fauna Guarantee Action Statement No.156 Metallic Sun-orchid , Department of Sustainability & Environment, Victoria link to DSE Action Statement No.156 (133 Kb)
  • Coates, F., Jeanes, J. and Pritchard, A. (2002). Recovery Plan for Twenty- five Threatened Orchids of Victoria, South Australia and New South Wales 2003 - 2007. Department of Sustainability and Environment, Melbourne. Dept. of Environment & Heritage Recovery Plan
  • Cropper S., Calder D.M., Tonkinson D. (1989) Thelymitra epipactoides F. Muell (Orchidaceae), the morphology, biology and conservation of an endangered species. Report to National Parks Service, Victoria, scientific permit No. 856/019.
  • Cropper S.C., Calder D.M. (1989) The floral biology of Thelymitra epipactoides F. Muell (Orchidaceae), and the implications of pollination by deceit on the survival of this rare orchid. Report to National Parks Service, Victoria, scientific permit No.856/019. In; Plant Systematics and Evolution 158:11-82.
  • Department of the Environment and Heritage (2006). Thelymitra epipactoides in Species Profile and Threats Database, Department of the Environment and Heritage, Canberra. link to DEH Metallic Sun-orchid


Management partnerships Parks Victoria actively monitor and manage habitat for this species in Port Campbell National Park and Bay of Islands Coastal Park. Ecological burns targetted at Metallic Sun-orchid have been conducted in Port Campbell National Park during 2004 & 2005.


Community groups including: the Portland Field Naturalist, the Bairnsdale and Districts Field Naturalists, Grampians Threatened Species Group and the Australasian Native Orchid Society have all been actively involved in the recovery program for this species.


See also:


Update on management activities

In 2010 a draft re-introduction plan was developed for Thelymitra epipactoides and circulated amongst the Recovery Team for comment. This plan sets out the most important activities to be undertaken to ensure recovery of this species.

A monitoring system of recording demographic information such as leaf emergence, flowering, pollination, grazing and recruitment has been established across three Metallic Sun-orchid sites in western Victoria Lake Mundi, Kiata, Flaxman’s Hill and Port Campbell. Ongoing comparative data from these three sites will be used to further define management actions and priorities for this species.

In 2010 a collaborative research project was initiated as part of an Australian Orchid Foundation project with RMIT University, University of Melbourne, Royal Botanic Gardens and DSE. The project will run for three years and will investigate the edaphic conditions experienced by Metallic Sun-orchids, the identity and diversity of mycorrhizal populations associated with these populations, whether mycorrhizal fungi form tripartite links with associated flora, and the optimal in-vitro germination and nursery growth conditions to raise these plants.

A collection of approximately 3,000 propagated plants is being maintained at the Horsham Orchid Propagation Facility genetic material sourced from Lake Mundi, Kiata and Port Campbell. These are now ready for introduction into the wild, commencing in the Wimmera July 2012.


Wimmera

International Student Volunteers and DSE Land and Fire Indigenous trainees completed weed and rabbit management works in preparation for a re-introduction in July 2011.

At Kiata, all 15 plants in which flowered were individually cross pollinated and parentage setting seed recorded. Seed from these plants were harvested for propagation and the site was re-stocked with seed in autumn. Ten root samples were harvested from plants throughout the reserve and taken to the Horsham Orchid Facility to isolate the mycorrhiza. Thirty mycorrhizal isolates were successfully harvested and used for both propagation and phylogenetic analysis. Successful growth of the first germinants of Metallic Sun-orchid. Plants are now available for reintroduction into natural habitat.

As part of collaboration led by Dr Wright at the University of Melbourne preliminary sequencing revealed two species of mycorrhizal fungi (Tulasnella asymmetrica and Tulasnella violea-type) to associate and in subsequent experiments germinate (1 year old) Metallic Sun-orchids. Initial work undertaken includes 30 root samples across three sites being isolated for mycorrhizal fungi resulting in 90 mycorrhizal isolates. A weather station was installed, maintained and data on soil moisture and temperature at differing depths recorded. Monitoring established at three sites with associated vegetation being collected for tripartite propagation. Ninety isolates symbiotically sown with seed and mycorrhiza were sent to RMIT University for sequencing.

The Wimmera Orchid Lab. Lead by Dr Noushka Reiter from the Wimmera Catchment Management Authority has successfully raised 3000 Metallic Sun-orchids which are being introduced to four sites in south-west Victoria over the next 12 months, starting with two sites in the Little Desert National Park in July 2012. This is the first large scale reintroduction of an endangered orchid species in Australia. The project team includes the Australian Orchid Foundation, Australian Native Orchid Society, RMIT University, Royal Botanic Gardens Melbourne, Department of Sustainability and Environment, Department of Primary Industries, Wimmera CMA and many enthusiastic volunteers.


Corangamite CMA area

Three 2 x 2m plots were established across the entire known population at Deaney’s Steps within the Port Campbell National Park in 2010. The Bay of Island Population was burnt in March 2011. An ecological burn of the population at Deaney’s Steps is scheduled for February / March 2012, which is in line with the recommended frequency / timing for this species. The area of the burn has been increased to include plants that were located outside the area burnt in 2005.


Glenelg Hopkins

An ecological burn at Flaxman’s Hill was conducted in March 2011, which was in line with the recommended frequency / timing for this species. The area of the burn was increased to include plants that were located outside the area burnt in 2005.

Surveying and caging of additional plants at Flaxman’s Hill was undertaken in partnership with International Student Volunteers in June 2011. During this survey, all uncaged flowering plants were identified and caged to minimise the risk of browsing from macropods and deer, a key threat at this site. The cages appear to be effectively protecting plants from grazing post-fire. There is scope to install more cages at the site, if uncaged orchids are seen to be impacted by grazing. The demographic monitoring transect was also completed during this visit. Results indicate less than one percent of the individual marked plants have emerged post-fire.




This BIRD page is brought to you by the State Wide Integrated Flora & Fauna Team.

Feel free to edit, but please take care to preserve the integrity of the data. For example, listed management actions are derived from FFG Action Statements and the Actions for Biodiversity Conservation database administered by DEPI and should not normally be changed without prior discussion.

SWIFFT does not warrant the accuracy or completeness of information on this page and any person using or relying upon such information does so on the basis that the SWIFFT shall bear no responsibility or liability whatsoever for any errors, faults, defects or omissions in the information.

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