Prasophyllum canaliculatum D.L. Jones - critically endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list Prasophyllum canaliculatum D.L. Jones, a leek orchid, as a CRITICALLY ENDANGERED SPECIES on Part 1 of Schedule 1A of the Act. Listing of critically endangered species is provided for by Part 2 of the Act.

The Scientific Committee has found that:

1. Prasophyllum canaliculatum D.L. Jones is an endemic Australian orchid that has been described by Jones (1997) as follows:

"Tuberous terrestrial herb growing singly or in tufts of 2-4 plants. Tubers not seen. Leaf erect, 25-40 cm long, 3-5 mm wide, terete, bright green, base 2-3 mm across, reddish to purplish; free lamina erect, 12-20 cm long, usually partly withered at anthesis. Inflorescence a moderately dense spike 5-11 cm long. Floral bracts obovate-elliptical, 3-4 mm long, c. 4 mm wide, closely embracing the ovary, apex apiculate. Ovaries at about 30° to the rachis, obovoid, 4-5 mm long, c. 2.5 mm wide, bright green. Flowers 5-25, 7-9 mm across, red, greenish red or brownish red, fragrant, sessile. Dorsal sepal ovate-lanceolate, 7.5-9 mm long, 4-5 mm wide, deflexed, apex recurved, acuminate, with 3 darker stripes. Lateral sepals free, linear-lanceolate, 7.5-9 mm long, c. 2 mm wide, erect or recurved, base not gibbous, distal margins involute, apex bidentate. Petals linear-lanceolate, 6.5-7.5 mm long, c. 2 mm wide, porrect to spreading, incurved distally, margins pale, apex obtuse to acute. Labellum sessile, porrect to obliquely erect, apex erect, at right angles to the basal part; lamina broadly ovate-elliptical, 6-7.5 mm long, 5-6 mm wide, suddenly contracted in the distal two-thirds to a short apical cauda c. 2 mm long, base not gibbous, margins widely flared, slightly irregular, apex subobtuse. Callus a broad rectangular plate, c. 4 mm long, c. 3 mm wide, green to reddish, folded distally into a deep channel which becomes filled with nectar, lateral margins raised above the lamina, a short tail-like extension apparent when the labellum is flattened. Column porrect from the end of the ovary, c. 3.5 mm long, c. 4.5 mm wide; appendages oblong-lanceolate, c. 3.5 mm long, c. 1 mm wide, slightly falcate, widely divergent, apex obtuse, truncate or emarginate, about as long as the stigmatic plate. Anther ovate, c. 2 mm long, c. 1.8 mm wide, rugose, dark brownish purple. Pollinarium c. 2.7 mm long; viscidium ovate, c. 0.4 mm long; hamulus ligulate, c. 0.6 mm long; pollinia c. 2 mm long, yellow, sectile. Stigma ovate-quadrate, c. 2.2 mm long, c. 2.2 mm wide, the rostellum about as high as the appendages."

2. In NSW, Prasophyllum canaliculatum has been recorded from two locations on the Monaro Tableland: a roadside in the Kybeyan area; and south east of Nimmitabel in South East Forests National Park (McPherson 2004), and thus has a very highly restricted geographic distribution. Targeted surveys of suitable habitat elsewhere in these districts have failed to locate additional populations of the species (McPherson 2004). A population near Tumbarumba, previously regarded as P. canaliculatum, is now recognised as a new and undescribed species of Prasophyllum (D.L. Jones, pers. comm.).

3. The Kybeyan population numbered c. 30 individuals in late 1996 (Jones 1997), however the species could not be relocated in February 2002 and December 2003 (McPherson 2004), and may be in decline at this location. The Nimmitabel population comprised c. 190 plants in January 2004 (McPherson 2004). Therefore, the total number of mature individuals in NSW is currently estimated to be very low (c. 190 - 220 plants).

4. Prasophyllum canaliculatum is also found in the Australian Capital Territory, where a single population comprising c. 220 individuals occurs on forestry land. It is not currently listed or protected under the Nature Conservation Act 1980 or the Environment Protection and Biodiversity Conservation Act 1999.

5. Threats affecting the NSW populations include rooting by feral pigs, grazing by feral deer, weed invasion and illegal off-road vehicle traffic at the Nimmitabel site (McPherson 2004), and weed invasion and periodical mowing for fire protection purposes at the Kybeyan site (K. McDougall pers. comm.). Both sites continue to be threatened by environmental and demographic stochasticity due to their very small areas and population sizes. It may be inferred from these threats that Prasophyllum canaliculatum is suffering a continuing decline or will suffer a projected decline in abundance, geographic distribution or habitat quality.

6. Prasophyllum canaliculatum D.L. Jones is eligible to be listed as a critically endangered species as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

Clause 15

The geographic distribution of the species is estimated or inferred to be:

(a) very highly restricted, and

(d) a projected or continuing decline is observed, estimated or inferred in either:

    (i) an index of abundance appropriate to the taxon, or

    (ii) geographic distribution, habitat quality or diversity, or genetic diversity


Clause 16

The estimated total number of mature individuals of the species is:

(f) very low, and

(d) a projected or continuing decline is observed, estimated or inferred in either:

    (i) an index of abundance appropriate to the taxon, or

    (ii) geographic distribution, habitat quality or diversity, or genetic diversity


Professor Lesley Hughes

Chairperson

Scientific Committee

Proposed Gazettal date: 10/08/07

Exhibition period: 10/08/07 - 28/09/07

References

Jones DL (1997) Prasophyllum canaliculatum, an endangered new species of Orchidaceae from southern New South Wales. The Orchadian 12, 124-127.

McPherson P (2004) Prasophyllum canaliculatum Kybeyan and Tantawangalo Targeted Flora Survey Report. NGH Environmental unpublished report.

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Page last updated: 28 February 2011