Prasophyllum pallens D.L.Jones - vulnerable species listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the terrestrial orchid Prasophyllum pallens D.L.Jones as a VULNERABLE SPECIES in Part 1 of Schedule 2 of the Act. Listing of Vulnerable species is provided for by Part 2 of the Act.
NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. Prasophyllum pallens D.L.Jones (family Orchidaceae) is a terrestrial herb of the Leek Orchid genus. It is described by Jones (2006) as follows: "Leaf 200-400 x 3-4 mm. Inflorescence 300-500 mm tall. Spike 60-100 mm long, 15-30-flowered. Flowers crowded, 18-21 x 8-11 mm, pale tawny green to whitish, strong musty scent. Dorsal sepal 9.5-11 x 2.5-3 mm. Lateral sepals free, 9.5-11 x 2.5 mm, nearly straight, parallel with divergent tips. Petals 8.5-9 x 1.3-1.5 mm, projecting forward, pointed. Labellum sharply recurved and constricted near the middle, 10-12 x 5.5-6 mm, pointed. Callus extending nearly to labellum apex, wrinkled towards tip".
2. Prasophyllum pallens was first described by Jones (2000) from Mount Banks in the Blue Mountains National Park. Prior to this, the species had been included within a broadly defined P. fuscum ( e.g. Bernhardt & Rowe 1993; Bishop 2000). Recent research has shown that P. fuscum, in the strict sense, is restricted to an area south-west of Sydney. Although similar, P. fuscum can be distinguished by having paler-coloured flowers (Jones 2000).
3. Prasophyllum pallens is endemic to New South Wales where it is known only from the Blue Mountains, west of Sydney. The species is presently known from four distinct populations: Mt Banks and Mt Hay in the Blue Mountains National Park, and near the townships of Blackheath and Wentworth Falls. Historical records suggest that it once occurred near Leura, Bell and Mount Victoria, although these townships have expanded since the species was collected and it is unclear whether these populations persist.
4. Prasophyllum pallens grows in dense low heath in moist to wet shallow sandy soils over sandstone mostly at altitudes greater than 900 m above sea level (Jones 2000). Like many ground orchids, P. pallens has a dormant phase during late summer and resprouts from an underground tuber in Autumn to form a short leaf. This leaf may develop further and plants may flower from November to December. The fire response of P. pallens is well known with flowering being strongly promoted by fires that occur during the previous summer season (Bishop 2000; Jones 2000). Like most Australian terrestrial orchids, the species is believed to be semi- or fully-dependent on a mycorrhizal symbiont.
5. Prasophyllum pallens has a highly restricted geographic distribution. Its extent of occurrence is estimated to be approximately 140 km2 (Copeland 2008). The area of occupancy is no more than 28 km2 based on the species occupying seven 2 x 2 km grids, the spatial scale of assessment recommended by IUCN (2008).
6. The total population of Prasophyllum pallens is difficult to estimate due to the variable number of plants that flower each season, but is likely to include at least 450 and fewer than 1000 mature individuals (Copeland 2008).
7. Populations of Prasophyllum pallens close to urban areas may be threatened by further clearing of its habitat and inappropriate fire regimes and the species' small, restricted populations may be susceptible to stochastic events. 'Clearing of native vegetation' is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
8. Prasophyllum pallens D.L.Jones is not eligible to be listed as an Endangered or Critically Endangered species.
9. Prasophyllum pallens D.L.Jones is eligible to be listed as a Vulnerable species as, in the opinion of the Scientific Committee, it is facing a high risk of extinction in New South Wales in the medium-term future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:
Clause 17
The total number of mature individuals of the species is observed, estimated or inferred to be:
(c) low.
Clause 18
The geographic distribution of the species is observed, estimated or inferred to be very highly restricted such that it is prone to the effects of human activities or stochastic events within a very short time period.
Dr Richard Major
Chairperson
Scientific Committee
Proposed Gazettal date: 12/02/10
Exhibition period: 12/02/10 – 09/04/10
References
Bernhardt P, Rowe RR (1993) Prasophyllum. In 'Flora of New South Wales. Vol.4'. (Ed. GJ Harden) pp. 155-163 (University of New South Wales Press: Sydney)
Bishop T (2000) 'Field guide to the orchids of New South Wales and Victoria. 2nd edition' (University of New South Wales Press: Sydney)
Copeland LM (2008) 'Clarification of the taxonomy, and a reassessment of the conservation status, of Prasophyllum fuscum, P. uroglossum and P. pallens (Orchidaceae) in NSW' Report to the NSW Scientific Committee, Sydney.
IUCN (2008) 'Guidelines for using the IUCN Red List Categories and Criteria. Version 7.0.' (Standards and Petitions Working Group of the IUCN Species Survival Commission Biodiversity Assessments Sub-committee: Switzerland).
Jones DL (2000) Ten new species of Prasophyllum R.Br. (Orchidaceae) from south-eastern Australia. The Orchadian 13, 148-173.
Jones DL (2006) 'A complete guide to native orchids of Australia including the Island Territories'. (Reed New Holland: Sydney)