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 Endangered
Listing and Conservation Advices Commonwealth Conservation Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee, 2008adm) [Conservation Advice].
 
Commonwealth Listing Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee (TSSC), 2008adz) [Listing Advice].
 
Recovery Plan Decision Recovery Plan not required, local actions are being undertaken to assist the species, therefore the approved Conservation Advice for the species provides sufficient direction to implement priority actions and manage key threats (14/11/2008).
 
Adopted/Made Recovery Plans
Other EPBC Act Plans Flora Recovery Plan: Tasmanian Threatened Orchids 2006-2010 (Threatened Species Section (TSS), 2006a) [Recovery 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 (59) (14/11/2008) (Commonwealth of Australia, 2008m) [Legislative Instrument].
 
State Government
    Documents and Websites
TAS:Threatened Species Notesheet - Prasophyllum crebriflorum (Tasmanian Department of Primary Industries, Parks, Water and Environment (Tas. DPIPWE), 2009g) [Information Sheet].
TAS:Prasophyllum crebriflorum (Crowded Leek-Orchid): Species Management Profile for Tasmania's Threatened Species Link (Threatened Species Section (TSS), 2014as) [State Action Plan].
State Listing Status
TAS: Listed as Endangered (Threatened Species Protection Act 1995 (Tasmania): September 2012 list)
Scientific name Prasophyllum crebriflorum [78897]
Family Orchidaceae:Orchidales:Liliopsida:Magnoliophyta:Plantae
Species author D.L.Jones
Infraspecies author  
Reference D.L.Jones (2003), Muelleria 18: 103, fig. 3
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: Prasophyllum crebriflorum

Common name: Crowded leek-orchid

This species is conventionally accepted (Buchanan 2005).

The Crowded Leek-orchid is a small, fleshy, terrestrial orchid with a single green onion-like leaf up to 26 cm long. The flowering stem emerges from the end of the leaf and has a spike of crowded, widely opening reddish-brown flowers (Jones 2003).

The Crowded Leek-orchid has a solitary erect leaf which is 12–26 cm long, 2–5 mm wide, terete (circular in cross-section) and dark green. The base of the leaf is 2–3 mm in diameter and reddish to purple in colour. The free lamina (leaf blade) is suberect, 6–10 cm long and usually withered at flowering time. Inflorescence (flower cluster) is a moderately dense to dense spike 6–20 cm long. There are 6–25 flowers that are 10–12 mm across, reddish-brown in colour, sessile (without a stalk), open very widely and are fragrant (Jones 2003).

The Crowded Leek-orchid is endemic to north-western Tasmania, where it is known from two sites in the Surrey Hills area to the south-east of Hellyer Gorge (Jones 2003).

There are no estimates on the extent of occurrence of the Crowded Leek-orchid. The species is known from only two very small patches separated by 2.7 km (TSS n.d., unpubl. data).

The area of occupancy is estimated to be 0.007 km². This figure was estimated using data from two discrete patches with areas of 100 m by 50 m and 80 m by 20 m, respectively (TSS n.d., unpubl. data).

The Crowded Leek-orchid occurs in one location. The species is known from two sites, both of which are on private land under the same ownership. Changes to current land practices have the potential to eliminate the species from each of these sites (TSS n.d., unpubl. data).

There is insufficient data to determine whether Crowded Leek-orchid distribution is severely fragmented. It is considered likely that the plants at Surrey Hills represent the remnants of a once more widespread population that has been fragmented since European settlement. The Surrey Hills were settled in the very early days of the Tasmanian colony (1800s). A change in land use to agriculture and plantations may have resulted in some fragmentation of the Crowded Leek-orchid (R. Schahinger 2005, pers. comm.).

Montane grasslands in north-western Tasmania were subjected to increasing botanical interest over a period of 25 years (Kirkpatrick & Duncan 1987), with a particular focus on private land in the known stronghold of the Crowded Leek-orchid at Surrey Hills (Craven 1998; Gilfedder 1995). Grasslands on land managed by Forestry Tasmania in adjacent areas have also been subject to recent surveys (for example Craven et al. 2000; Johnson 2003). Targeted surveys for the Crowded Leek-orchid were undertaken in the Surrey Hills grasslands in December 2000 and January 2001, with no new populations being discovered (TSS n.d., unpubl. data).

Given the history of survey effort, it is unlikely that any new populations of the Crowded Leek-orchid will be found elsewhere.

The total population size of this species is estimated to be 125–135 mature individuals. Surveys to determine population size were undertaken at the same location in December 2000 and January 2001 (TSS n.d., unpubl. data). Estimates of population size and area of occupancy are based on field observations and are considered a close representation of the actual population size.

The Crowded Leek-orchid has been recorded from two subpopulations 2.7 km apart, separated by areas of unsuitable habitat (TSS n.d., unpubl. data).

There is insufficient data to determine whether the Crowded Leek-orchid undergoes extreme natural fluctuations in population numbers. Based on the experience with other Prasophyllum species, one might reasonably expect year-to-year fluctuations in the number of flowering plants in response to, as yet, undetermined environmental triggers (Jones et al. 1999).

Plant longevity and age at reproductive maturity have yet to be determined for this species. Coates and colleagues (1999) concluded that it was virtually impossible to correlate life history stages with plant age for the closely allied Gaping Leek-orchid (Prasophyllum correctum), due to the difficulty in observing seedling recruitment and the fact that plants may return to a sterile state resembling very young plants after flowering the previous year (Coates et al. 1999).

The Crowded Leek-orchid occurs in montane tussock grassland dominated by Tussock Grass (Poa labillardierei) with associated herbs Sky Lily (Herpolirion novae-zelandiae), Trachymene humilis, Diuris monticola and scattered patches of the woody shrub, Small-fruit Hakea (Hakea microcarpa). The species grows in brown clay loams derived from Tertiary basalts at altitudes of 660–670 m above sea level, with an annual rainfall greater than 2000 mm (Craven 1998; Jones 2003).

The Crowded Leek-orchid grows within 'Highland Poa grassland' (Harris & Kitchener 2005). This community is considered to be threatened in Tasmania although it is yet to be listed formally under either Tasmanian or Commonwealth legislation. Amendments to legislation for the protection of threatened non-forest communities such as highland Poa grassland were tabled in the Tasmanian Parliament in December 2005 (TSS n.d., unpubl. data).

The Crowded Leek-orchid is associated with several species listed on the Tasmanian Threatened Species Protection Act 1995, including the rare herbs White Sunray (Rhodanthe anthemoides) and Viola cunninghamii, and the vulnerable butterfly, Oreixenica ptunarra (TSS n.d., unpubl. data).

The Crowded Leek-orchid flowers in late November and December. Studies on the closely related Gaping Leek-orchid (Prasophyllum correctum) indicate that plants may not appear every year, and may survive below ground in a dormant state for up to five years (Coates et al. 1999). Nothing is known of the conditions required to stimulate flowering, nor its pollination mechanisms. Orchids have a complex and poorly understood interrelationship with species-specific mycorrhizal fungi and insect pollinators (Jones et al. 1999). Native bees, wasps and beetles are known to be effective pollinators for other Prasophyllum species, while some species can also be self-pollinating (Jones et al. 1999).

The Crowded Leek-orchid can be distinguished from other members of the Prasophyllum group by its very dense flower spike and its widely opening reddish-brown flowers (Jones 2003). It is most similar in appearance to Golfers Leek-orchid (Prasophllyum incorrectum), a species which occurs in lowland grasslands of Tasmania. However, Golfers Leek-orchid has more widely spaced flowers, and also differs in labellum (lip) and callus (protruding mass of hardened tissue) characters (Jones 2003).

Surveys should be undertaken during the species' flowering period, late November and December.

Considerable areas of potential habitat for the Crowded Leek-orchid in Tasmania's north-west are thought to have been lost through changed land use since European settlement, with the demise of an unknown number of plants. Montane grasslands in the area have been impacted upon by conversion to plantation since the 1950s (Kirkpatrick & Duncan 1987). In addition, at least some of the native grasslands in the key Surrey Hills area are known to have been aerially fertilised to improve grass quality (for cattle grazing) in the post-1950s period. These grasslands have also been subjected to regular spring burns, approximately every two to three years (Craven 1998).

The Crowded Leek-orchid shares similar characteristics as other Tasmanian Leek-orchids associated with native grasslands, such as the Pungent Leek-orchid (Prasophyllum olidum), the Turnbridge Leek-orchid (Prasophyllum tunbridgense), and also the recently described Graveside Leek-orchid (Prasophyllum taphanyx) and Golfers Leek-orchid (Prasophyllum incorrectum) (Jones et al. 1999; Jones 2003, 2004c). Each of these species is confined to very small sites (and usually numbers) among larger seemingly similar habitats, or with seemingly similar sites available in the district. It is assumed that their distribution was always patchy, but the number of sites has been drastically reduced due to habitat loss and/or degradation (Jones et al. 1999).

Inappropriate fire frequencies are considered to be the greatest future threat to the species. As herbs requiring light and some space, orchids may be shaded out in tussock grasslands that are allowed to grow rank without some form of disturbance. Leek-orchids do possess tubers, and might therefore be expected to persist in a dormant state during unfavourable conditions. However, the longer the period without flowering and fresh seed production, the less likely the long-term persistence of a species in an area (Jones et al. 1999). Conversely, the long-term impact of regular spring burning of the species' grassland habitat during the latter half of the 20th century remains to be determined.

Additional short-term future threats include land clearance and conversions of the montane grassland habitat. The application of fertilisers to native grasslands may dramatically change the soil of an area, usually to the detriment of orchids. Not only are orchids hampered by the increased competition created by invigorated growth of pasture plants and weeds, but they also suffer as their mycorrhizal fungus takes up phosphorus and quickly concentrates phosphates to a toxic level (Jones et al. 1999).

The Crowded Leek-orchid has a very restricted area of occupancy, thus exposing the species to the effects of human activities or stochastic events (TSS n.d., unpubl. data).

Minister's reason for Recovery Plan decision:

Local actions are being undertaken to assist the species. Therefore the approved Conservation Advice for the species provides sufficient direction to implement priority actions and manage key threats. A recovery plan is not considered to be necessary at this time.

The Threatened Species Scientific Committee (2008adm) recommend the following local and regional priority recovery and threat abatement actions:

  • Protect areas of native vegetation which contain subpopulations of the species or which could support subpopulations in the future.
  • Ensure chemicals used to control weeds do not impact on the species.
  • Investigate options for establishing additional subpopulations.
  • Undertake seed germination and/or vegetative propagation trials to determine the requirements for successful establishment, including mycorrhizal association trials.
  • Monitor known sites to identify any changes in threats or numbers of individuals.
  • Undertake surveys of suitable habitat or potentially suitable habitat to locate any additional subpopulations.
  • Encourage land management activities that benefit the species.
  • Investigate formal conservation arrangements, such as covenants or inclusion in reserve tenure, for the subpopulations not currently reserved.
  • Identify appropriate intensity and interval of fire to promote seed germination.

    The Crowded Leek-orchid's long-term future at its two known sites relies upon the goodwill of the present landowner and the maintenance of an appropriate management regime. Both known subpopulations occur in informal 'grassland reserves'. Fire management plans have been prepared for these grasslands to encourage an open Poa sward and maintain herb diversity (Craven 1998).

    Legislative protection of highland Poa grassland in Tasmania is pending, which should prevent future clearance or conversion of the species' habitat. However, a formal management arrangement with the landowner is desirable, either through a conservation covenant under the Tasmanian Nature Conservation Act 2002 or a land management agreement under the Tasmanian Threatened Species Protection Act 1995. The relevant agencies to promulgate such agreements are the Non-forest Vegetation Program or the Protected Areas on Private Land program, both within the Tasmanian Department of Primary Industries, Water and Environment.

    The following issues identified for other Prasophyllum species in the Flora Recovery Plan for Tasmanian Threatened Orchids 2006–2010 (TSS 2006a) should also be pursued to better understand the Crowded Leek-orchids management requirements:

    • the significance of fire (timing/frequency) as a cue to germination and/or flowering
    • an examination of the species' reproductive biology
    • genetic surveys of the population to better inform any future ex situ propagation programs
    • raising community awareness as to the plight of threatened species in native grassland remnants.

  • 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
    Agriculture and Aquaculture:Agriculture and Aquaculture:Fertiliser application Commonwealth Listing Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee (TSSC), 2008adz) [Listing Advice].
    Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation Commonwealth Conservation Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee, 2008adm) [Conservation Advice].
    Commonwealth Listing Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee (TSSC), 2008adz) [Listing Advice].
    Agriculture and Aquaculture:Livestock Farming and Grazing:Habitat loss and modification due to clearance of native vegetation and pasture improvements Commonwealth Conservation Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee, 2008adm) [Conservation Advice].
    Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat loss, modification and/or degradation Commonwealth Listing Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee (TSSC), 2008adz) [Listing Advice].
    Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) Commonwealth Conservation Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee, 2008adm) [Conservation Advice].
    Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Commonwealth Listing Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee (TSSC), 2008adz) [Listing Advice].
    Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Commonwealth Conservation Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee, 2008adm) [Conservation Advice].
    Commonwealth Listing Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee (TSSC), 2008adz) [Listing Advice].
    Species Stresses:Indirect Species Effects:Low numbers of individuals Commonwealth Conservation Advice on Prasophyllum crebriflorum (Threatened Species Scientific Committee, 2008adm) [Conservation Advice].

    Buchanan, A.M. (2005). A Census of the Vascular Plants of Tasmania & Index to the Students Flora of Tasmania. Fourth Edition. Tasmanian Herbarium Occasional Publication No. 7. Hobart, Tasmania: Tasmanian Museum and Art Gallery.

    Coates, F., I. Lunt & H. Wapstra (1999). Draft Recovery Plan 2000-2002 Prasophyllum correctum D.L. Jones (Gaping Leek-orchid). Environment Australia.

    Craven, B. (1998). Vegetation management plan for Surrey Hills grassland reserves, northwest Tasmania. Unpublished report to North Forests Burnie.

    Craven, B., F. Duncan & G. Miller (2000). Grasslands and grassy woodlands of significance in Mersey district. Unpublished report to Forestry Tasmania.

    Gilfedder, L. (1995). Montane grasslands of north-western Tasmania. Unpublished report to North Forests Burnie & Forestry Tasmania.

    Harris, S. & A. Kitchener (2005). From Forest to Fjaeldmark: Descriptions of Tasmania's Vegetation. Hobart, Tasmania: Department of Primary Industries, Parks, Water and Environment.

    Johnson, K. (2003). Grasslands and grassy woodlands. Unpublished report to Forestry Tasmania, Mersey District.

    Jones, D.L. (2003). A revisionary treatment of four species of Prasophyllum R.Br. (Orchidaceae) loosely related to P. correctum D.L.Jones. Muelleria. 18:99-109.

    Jones, D.L. (2004c). Two new species of Prasophyllum R.Br. (Orchidaceae) from Tasmania. The Orchadian. 14 (8):372-377.

    Jones, D.L., H. Wapstra, P. Tonelli & S. Harris (1999). The Orchids of Tasmania. Carlton South, Victoria: Melbourne University Press.

    Kirkpatrick, J.B. & F. Duncan (1987). Distribution, community composition and conservation of Tasmanian high altitude grassy ecosystems. Australian Journal of Ecology. 12:73-86.

    Schahinger R. (2005). Personal communication.

    Threatened Species Scientific Committee (2008adm). Commonwealth Conservation Advice on Prasophyllum crebriflorum. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/78897-conservation-advice.pdf.

    Threatened Species Section (TSS) (2006a). Flora Recovery Plan: Tasmanian Threatened Orchids 2006-2010. [Online]. Hobart, Tasmania: DPIWE. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/tasmanian-orchid.html.

    Threatened Species Section (TSS) (no date). Unpublished data held by the Threatened Species Section. Tasmanian Department of Primary Industries, Water and Environment (DPIWE), Hobart.

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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). Prasophyllum crebriflorum in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Thu, 2 Oct 2014 21:31:14 +1000.