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 Critically Endangered as Nematoceras dienemum
Listing and Conservation Advices Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010c) [Listing Advice].
 
Commonwealth Conservation Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010d) [Conservation Advice].
 
Recovery Plan Decision Recovery Plan not required, the approved conservation advice for the species provides sufficient direction to implement priority actions and mitigate against key threats (09/02/2010).
 
Adopted/Made Recovery Plans
Other EPBC Act Plans Plan for the Eradication of Rabbits and Rodents on Subantarctic Macquarie Island (Tasmania Parks & Wildlife Service (Tas. PWS), 2007a) [Threat Abatement 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
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (91) (09/02/2010) (Commonwealth of Australia, 2010k) [Legislative Instrument] as Nematoceras dienemum.
 
State Government
    Documents and Websites
TAS:Macquarie Island Nature Reserve and World Heritage Area Management Plan (Tasmania Parks & Wildlife Service (Tas. PWS), 2006) [Management Plan].
TAS:Macquarie Island Pest Eradication Project Plan (Tasmania Parks & Wildlife Service (Tas. PWS), 2008a) [Management Plan].
TAS:Nematoceras dienemum (Windswept Helmet-orchid): Species Management Profile for Tasmania's Threatened Species Link (Threatened Species Section (TSS), 2014fj) [State Action Plan].
State Listing Status
TAS: Listed as Vulnerable (Threatened Species Protection Act 1995 (Tasmania): September 2012 list) as Nematoceras dienemum
Scientific name Nematoceras dienemum [81970]
Family Orchidaceae:Orchidales:Liliopsida:Magnoliophyta:Plantae
Species author (D.L.Jones) D.L.Jones, M.A.Clem. & Molloy
Infraspecies author  
Reference Jones, D.L., Clements, M.A., Sharma, I.K. , Mackenzie, A.M. & Molloy, B. (2002), The Orchadian 13(10): 449 [comb. nov.]
Other names Corybas dienemus [68807]
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: Nematoceras dienemum

Common name: Windswept Helmet-orchid

The species is conventionally accepted as Nematoceras dienemum (Windswept Helmet-orchid) (Jones et al. 2002).

Nematoceras dienemum was previously known as Corybas dienemus (TSSC 2010c).

The Windswept Helmet-orchid is a small (3–5 cm tall), tuberous terrestrial orchid, which forms small clonal groups. Its leaves are flattish, fleshy and solitary with dark green colouring above and silvery-green colouring below. The flowers are erect and green with purplish-red markings (Clements & Jones 2007).

The Windswept Helmet-orchid occurs at ten locations on the northern half of Macquarie Island, 1500 km south-east of Hobart, Tasmania. The species occurs in moist areas on the coastal rim less than 30 m above sea level (TSSC 2010c).

The species' extent of occurrence is approximately 45 km² and the area of occupancy is about 1.5 km² (TSSC 2010c).

The total population numbers for the Windswept Helmet-orchid are approximately 7500 plants. The estimated total number of mature individuals of the Windswept Helmet-orchid is not known (TSSC 2010c).

From 1997–2007 there was a 50% reduction in the area of occupancy of the species at one location at Bauer Bay. This decline was primarily caused by the development of a seal wallow, as well as to a lesser extent, disturbance by rabbits. It is estimated that up to 500 orchids were killed during this period. The species has been observed to recolonise the edges of this seal wallow and is showing some tolerance to this disturbance. Identified threats to the species may have caused a decline in population size at other locations apart from Bauer Bay; however, there are no data available regarding declines at other locations on the island. Given the total population is approximately 7500 plants, the loss of approximately 500 individual orchids does not represent a substantial reduction in numbers (TSSC 2010c).

Current information suggests that the population size may actually increase in the future if the implementation of the Macquarie Island Pest Eradication Plan (Tas. PWS 2008a) is successful in eradicating Rabbits from Macquarie Island (TSSC 2010c).

The Windswept Helmet-orchid is found on the lower coastal terraces (less than 30 m above sea level) and peat wetlands where the vegetation is dominated by mosses which float on a waterlogged underlayer. The soil substrate is waterlogged peat where the water-table is very close to the soil surface (Clements & Jones 2007).

The mire vegetation is dominated by sedges, Isolepis aucklandica (New Zealand Club sedge) and Juncus scheuchzeroides; small herbs, Epilobium pedunculare (Rockery Willowherb) and Hydrocotyle novae zeelandiae; cushion plants, Colobanthus muscoides and Colobanthus affinis (Alpine Colobanth); and bryophytes (Clements et al. 2007). The species can also occur on the boundary of mire and herbfield where it grows beneath the megaherb Stilbocarpa polaris (Macquarie Island Cabbage) (Copson 1984). This ecotone is common on the north-west coast raised beach platform on Macquarie Island (TSSC 2010c).

The Windswept Helmet-orchid flowers from November–January (Shaw 2005). It produces seeds annually and has the capacity for vegetative reproduction. Vegetative reproduction, through production of daughter root-tubers on lateral, underground and elongate stolons, is the most common form of reproduction in the Nematoceras genus (Clements et al. 2007). Leaves die off each autumn and new leaves emerge in spring from existing stems and root-tubers (Shaw 2005). The life expectancy and age of sexual maturity of the Windswept Helmet-orchid are unknown. However, given the capacity for vegetative reproduction it is likely that some clonal patches (colonies) have existed for several decades (TSSC 2010c).

The pollination method for the Windswept Helmet-orchid is unknown. One possible pollinator is the Black Fungus Gnat (Bradysia watsoni), which is common on the coastal terraces where the Windswept Helmet-orchid is found (Davies & Melbourne 1999).

The main identified threats to the Windswept Helmet-orchid are Rabbits (Oryctolagus cuniculus) and seal wallows. The main potential threat to the species is from climate change.

Rabbits
Rabbits are widespread across Macquarie Island, including in short herb vegetation and in grasslands. In 2008, Rabbit numbers were estimated to be over 100 000 on an island that is approximately 34 km long and 5.5 km wide (Tas. PWS 2007a). Rabbits have not been observed to directly graze on the Windswept Helmet-orchid and prefer not to place their burrows in wet areas where the species is found (Clements 2009, pers. comm., cited in TSSC 2010c). However, Rabbits do dig and scratch at the soil surface causing plants to be dislodged and left to die on the soil surface (Shaw 2005). Rabbit diggings also destabilise the peat soils causing land slips and the degradation and destruction of Windswept Helmet-orchid habitat. In addition, where Rabbits are active they deposit large (50 cm x 50 cm) piles of scats. The impact of nutrient deposition from scats has not been quantified, but it is likely that over time the release of nitrogen from scats will alter soil nutrient processes. Decomposition processes are slow in the subantarctic and piles of scats can smother individuals or small colonies leading to plant mortality (TSSC 2010c).

Studies have shown that Rabbit activity (grazing and burrowing) alters vegetation structure and composition (Copson & Whinam 1998), and may promote introduced grass species, such as Marchantia (liverworts) and Poa annua (Winter Grass), which have the ability to outcompete smaller species, including the Windswept Helmet-orchid. In addition, the removal of covering plants, such as Stilbocarpa polaris (Macquarie Island Cabbage) and Pleurophyllum hookeri (Silver Leaf Daisy), poses an indirect threat to the Windswept Helmet-orchid, increasing erosion and the exposure of the species to the elements (TSSC 2010c).

Current estimates indicate that Rabbit population numbers are broadly stable, with a possible shift of abundance from coastal areas to plateau areas. With the implementation of the Macquarie Island Pest Eradication Project (Tas. PWS 2008a) it is envisaged that the threat posed by Rabbits to the Windswept Helmet-orchid will be diminished in the future. Aerial baiting, which is scheduled for winter 2010 is likely to remove in excess of 95% of the rabbit population. Hunting is expected to eradicate the surviving Rabbits (TSSC 2010c).

Seals
Seals are known to utilise low lying areas, such as some of the locations where the Windswept Helmet-orchid is found, where they wallow in the water or mud causing the trampling or destruction of orchid habitat. A 50% reduction in the area covered by the species at Bauer Bay, between 1997–2007, is thought to be primarily as a result of the development of a seal wallow in the species' habitat, as well as the impact of Rabbits on the site. The species has been observed to recolonise the edges of this seal wallow and is showing some tolerance to this disturbance (TSSC 2010c).

Climate change
Climate change is having a significant effect on Macquarie Island with an increase in temperatures of >0.5 ºC in the past 50 years (AGDEW 2007be). As the Windswept Helmet-orchid only occurs in moist areas, shaded by larger plants, any drying out of these areas is likely to negatively impact on the species. Any sea level rise or increase in storm surges would also have a detrimental effect on this species in the short term. However, in the longer term it would be expected that the species would move above the tidal zone (TSSC 2010c).

Minister's Reasons for Recovery Plan Decision
A recovery plan for the species is not considered to be necessary at this time, as the approved conservation advice for the species provides sufficient direction to implement priority actions and mitigate against key threats.

The Commonwealth Conservation Advice on Nematoceras dienemum (Windswept Helmet-orchid) (TSSC 2010d) outlines the following research priorities:

  • Design and implement a monitoring program specifically for this species which assesses population size, distribution and the impact of various threats such as Rabbits.
  • Undertake survey work in suitable habitat and potential habitat to locate any additional occurrences of the species.
  • Undertake seed germination and vegetative propagation trials to determine the requirements for successful establishment, including mycorrhizal association trials.
  • Investigate the general biology and pollination biology of the species.

In addition, the Commonwealth Conservation Advice on Nematoceras dienemum (Windswept Helmet-orchid) (TSSC 2010d) outlines the following priority actions:

  • Monitor the progress of recovery, including the effectiveness of management actions such as the Rabbit eradication program and the need to adapt them if necessary.
  • Maintain Rabbit-proof wire cages around occurrences of the species at various locations and monitor their effectiveness. Adapt fencing as necessary and ensure this is an ongoing activity.
  • Identify and remove weeds in the local area, which could become a threat to the Windswept Helmet-orchid, using appropriate methods.
  • Manage sites to prevent introduction of invasive weeds, which could become a threat to the Windswept Helmet-orchid, using appropriate methods.
  • Monitor weed numbers and distribution in view of the potential increase in weeds that may occur following the successful elimination of Rabbits from the island.
  • Implement the Macquarie Island Pest Eradication Plan for the control and eradication of the European Rabbit in the region.
  • Where appropriate, manage Rabbit and seal disturbance at significant sites through exclusion fencing or other barriers.
  • Monitor the impact of grazing of Rabbits and seal wallows on the species.
  • Undertake appropriate seed and mycorrhizal fungi collection and storage.
  • Investigate options for linking, enhancing or establishing additional populations.
  • Implement national translocation protocols (Vallee et al. 2004) if establishing additional populations is considered necessary and feasible.

The Commonwealth Conservation Advice on Nematoceras dienemum (Windswept Helmet-orchid) (TSSC 2010d) provides a brief biological overview and management recommendations.

In addition, the following management plans are available:

  • Macquarie Island Pest Eradication Plan (Tas. PWS 2008a)
  • Plan for the Eradication of Rabbits and Rodents on Subantarctic Macquarie Island (Tas. PWS 2007a)
  • Macquarie Island Nature Reserve and World Heritage Area Management Plan (Tas. PWS 2006).

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
Climate Change and Severe Weather:Climate Change and Severe Weather:Climate change altering atmosphere/hydrosphere temperatures, rainfall patterns and/or frequency of severe weather events Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010c) [Listing Advice].
Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat modification with associated erosion Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010c) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation Oryctolagus cuniculus (Rabbit, European Rabbit) Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010c) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010c) [Listing Advice].
Invasive and Other Problematic Species and Genes:Problematic Native Species:Habitat degradation caused by seal wallows Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid) (Threatened Species Scientific Committee (TSSC), 2010c) [Listing Advice].

Australian Government Department of the Environment and Water Resources (AGDEW) (2007be). Australian Antarctic Division Data Centre. [Online]. Available from: http://aadc-maps.aad.gov.au/aadc/soe.

Clements, M.A. & D.L. Jones (2007). A new species of Nematoceras and characterisation of N. dienemum (Orchidaceae), both from subantarctic Macquarie Island. Telopea. 11:405-411.

Clements, M.A., A. McKenzie, G.R. Copson, B. Molloy, N. Carmichael, M. Skotnicki & P.Selkirk P. (2007). Biology and molecular phylogenetics of Nematoceras sulcatum, a second endemic orchid from subantarctic Macquarie Island. Polar Biology. 30:859-869.

Copson, G. & J. Whinam (1998). Response of vegetation on subantarctic Macquarie Island to reduced rabbit grazing. Australian Journal of Botany. 46:15-24.

Copson, G.R. (1984). An annotated atlas of the vascular flora of Macquarie Island. ANARE Research Notes. 18:1-70.

Davies, K.F. & B.A. Melbourne (1999). Statistical models of invertebrate distribution on Macquarie Island: a tool to assess climate change and local human impacts. Polar Biology. 21:240-250.

Jones, D.L., M. Clements, I. Sharma, A. Mackenzie & B. Molloy (2002). Nomenclatural notes arising from studies into the Tribe Diurideae (Orchidaceae). Banks, D.P., ed. The Orchadian. 13 (10):437-468.

Shaw, J.D. (2005). The reproductive ecology of vascular plants on subantarctic Macquarie Island. Ph.D. Thesis. Hobart, Tasmania: University of Tasmania.

Tasmania Parks & Wildlife Service (Tas. PWS) (2006). Macquarie Island Nature Reserve and World Heritage Area Management Plan. [Online]. Hobart, Tasmania: Department of Tourism, Arts and the Environment. Available from: http://www.parks.tas.gov.au/index.aspx?base=6182.

Tasmania Parks & Wildlife Service (Tas. PWS) (2007a). Plan for the Eradication of Rabbits and Rodents on Subantarctic Macquarie Island. [Online]. Hobart: Tasmania Parks and Wildlife Service. Available from: http://www.environment.gov.au/heritage/publications/protecting/macquarie-rabbit-eradication-plan.html.

Tasmania Parks & Wildlife Service (Tas. PWS) (2008a). Macquarie Island Pest Eradication Project Plan. [Online]. Hobart, Tasmania: Department of Environment, Parks, Heritage and the Arts. Available from: http://www.parks.tas.gov.au/?base=10516.

Threatened Species Scientific Committee (TSSC) (2010c). Commonwealth Listing Advice on Nematoceras dienemum (Windswept Helmet-orchid). [Online]. Department of the Environment, Water, Heritage and the Arts. Canberra, ACT: Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/81970-listing-advice.pdf.

Threatened Species Scientific Committee (TSSC) (2010d). Commonwealth Conservation Advice on Nematoceras dienemum (Windswept Helmet-orchid). [Online]. Department of the Environment, Water, Heritage and the Arts. Canberra, ACT: Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/81970-conservation-advice.pdf.

Vallee, L., T. Hogbin, L. Monks, B. Makinson, M. Matthes & M. Rossetto (2004). Guidelines for the translocation of threatened plants in Australia - Second Edition. Canberra, ACT: Australian Network for Plant Conservation.

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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). Nematoceras dienemum in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sun, 31 Aug 2014 20:15:56 +1000.