Calochilus pulchellus -endangered species listing

NSW Scientific Committee - Final Determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list an orchid Calochilus pulchellus D.L. Jones as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act. Listing of endangered species is provided for by Part 2 of the Act.

The Scientific Committee has found that:

1. Calochilus pulchellus D.L. Jones (Pretty Beard Orchid), (family Orchidaceae) is a terrestrial herb with a single upright sublinear leaf, sheathing the flowering stem briefly at the base; leaf fully developed at flowering time, longitudinally channelled, roughly trigonous in cross-section, 100-180 mm long, 4-8 mm wide, dark green with a dark red base. Flowering stem 200-300 mm tall, bearing 1-5 flowers on pedicels 6-12 mm long. Flowers lasting 2-4 days, 25-30 mm long by c. 20 mm wide, sepals and petals pale green or greenish yellow with darker reddish longitudinal striations, labellum hairs coppery red. Dorsal sepal triangular-ovate, 13-16 mm tall, 8-9 mm wide at base; lateral sepals subtriangular, 13-16 mm long, 5-6 mm wide at base; petals 8-9 mm long, 5-6 mm wide. Labellum flat, 28-30 mm long, 6-7 mm wide, basal few mm with short red calli (warts), remainder with coarse hairs to 6 mm long, labellum tip a tapering hairless tail 12-17 mm long; column with two small blackish sham ‘eyes’ adjacent to base of labellum, the eyes lacking a connecting ridge. Fruits have not yet been observed. Description adapted from Jones (2006a: 68-9, 2006b: 261; colour illustration in Jones 2006b: 261).

2. Calochilus pulchellus is similar to C. grandiflorus (Benth.) Domin, but the latter has a shorter leaf (30-50 mm long), a taller flowering stem (300-600 mm tall), and larger flowers (35-45 mm long, 22-28 mm broad, labellum 35-40 mm long). C. grandiflorus is not known to occur south of the Gosford area.

3. Calochilus pulchellus is endemic to New South Wales. It is known from the Sydney Basin Bioregion (sensu Thackway and Cresswell 1995), where a total of less than 30 adult plants have been recorded in three sites over a range of 40 km on the South Coast of NSW, at altitudes from 20-560 m a.s.l. All currently known sites are within the Shoalhaven Local Government Area. At Vincentia (five to nine plants) the species grows in dense low wet heath in wet sand over sandstone (Jones 2006a). In Booderee National Park (one plant recorded in 2004) it grows in a tall heathy association. In Morton National Park on the Little Forest Plateau (18 plants in 2004) it occurs in low heath among scattered clumps of emergent eucalypts and Banksia in shallow coarse white sand over sandstone (Jones 2006a), in a near-escarpment area subject to strong orographic precipitation. Occurrence in small widely separated colonies is not unusual in the genus.

4. The life cycle of C. pulchellus is typical for temperate zone members of the genus, with the leaf emerging from a subterranean tuber in mid-winter, and flowering occurring from late October to late November, with only one or two flowers open at a time and each flower lasting only 2-4 days. The plant dies back to tubers in later summer. The generation time and longevity of individual plants is unknown for this species. M. Clements (pers. comm. 2007) suggests that few plants survive the flowering effort more than once or twice. Over time the species is probably reliant on recruitment from seed rather than vegetative persistence. The flowering period is very short; the generic pattern (M Clements pers. comm. 2007) is for the flowers to be receptive to scoliid wasp pollination on day one, after which the interior configuration of the flower changes to make it inaccessible to pollinators but still receptive to self-pollination. Flowering is likely to be promoted by fire (Jones 2006b, M Clements pers. comm. 2007).

5. The cryptic nature of the species, with a single leaf above ground for only a few months and a flowering stem lasting days or weeks, makes detection difficult. It is likely that additional scattered individuals and small colonies exist within the area of occurrence.

6. The Vincentia site is on private land and is scheduled for clearing for a housing development in the near future. This will result in a decline of between 20% and 30% in the number of known plants. The Little Forest Plateau site is within Morton National Park and is unlikely to face threats other than inappropriate fire frequencies and possibly climate change. ‘High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and composition’ and ‘Anthropogenic climate change’ are listed as Key Threatening Processes under the Threatened Species Conservation Act. The very small colony sizes render the species liable to stochastic effects. Given that tubers may be exhausted after flowering, fire frequency is likely to be a management issue at all sites.

7. Calochilus pulchellus D.L. Jones is not eligible to be listed as a critically endangered species, due to the cryptic nature of the species giving rise to significant uncertainty as to absolute numbers.

8. Calochilus pulchellus D.L. Jones is eligible to be listed as an endangered species as, in the opinion of the Scientific Committee, it is facing a very 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:

(b) highly restricted,

and:

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

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

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

(e) the following conditions apply:

(i) the population or habitat is observed or inferred to be severely fragmented;

(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations.

Clause 16

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

(b) low,

and:

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

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

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

(e) the following conditions apply:

(i) the population or habitat is observed or inferred to be severely fragmented;

(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations.

Clause 17

The total number of mature individuals of the species is observed, estimated or inferred to be:

(b) very low.

 

Professor Lesley Hughes

Chairperson

Scientific Committee

Proposed Gazettal date: 23/05/08

Exhibition period: 23/05/08 – 18/07/08

References:

Jones DL (2006a) Miscellaneous new species of Australian Orchidaceae. In: Jones DL and Clements MA, New taxa of Australian Orchidaceae. [Australian Orchid Research vol. 5]. Australian Orchid Foundation, Essendon, Vic.

Jones DL (2006b) A complete guide to native orchids in Australia including the island territories. Reed New Holland, Frenchs Forest NSW.

Thackway R and Cresswell ID (1995) An interim biogeographic regionalisation for Australia. Version 4.0 Australian Nature Conservation Agency, Canberra.

 

Page last updated: 28 February 2011