Tadgell's bluebell (Wahlenbergia multicaulis) population, Auburn, Bankstown, Baulkham Hills, Canterbury, Hornsby, Parramatta and Strathfield Local Government Areas - endangered population listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the population of Tadgell's Bluebell Wahlenbergia multicaulis Benth., in the local government areas of Auburn, Bankstown, Baulkham Hills, Canterbury, Hornsby, Parramatta and Strathfield as an ENDANGERED POPULATION in Part 2 of Schedule 1 of the Act, and as a consequence, omit reference to the population of Tadgell's Bluebell Wahlenbergia multicaulis Benth., in the local government areas of Auburn, Bankstown, Strathfield and Canterbury from Part 2 of Schedule 1 (Endangered population) of the Act. Listing of endangered populations is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the population of Tadgell's Bluebell Wahlenbergia multicaulis Benth., in the local government areas of Auburn, Bankstown, Baulkham Hills, Canterbury, Hornsby, Parramatta and Strathfield as an ENDANGERED POPULATION in Part 2 of Schedule 1 of the Act, and as a consequence, omit reference to the population of Tadgell's Bluebell  Wahlenbergia multicaulis Benth., in the local government areas of Auburn, Bankstown, Strathfield and Canterbury from Part 2 of Schedule 1 (Endangered population) of the Act. Listing of endangered populations is provided for by Part 2 of the Act.

The Scientific Committee has found that:

1. Wahlenbergia multicaulis (family Campanulaceae) is not currently listed as an endangered species in Part 1 of Schedule 1 and as a consequence populations of this species are eligible to be listed as endangered populations.

2. Wahlenbergia multicaulis is described by P Smith (1992) in Harden G. J. (ed).  Flora of New South Wales. Vol. 3. p 120, UNSW Press, Sydney as: a perennial tufted herb, 10-75cm high, glabrous or sometimes sparsely hairy. The leaves are mostly linear 4-80mm long, 1-6mm wide, and entire or with small callus teeth. The flowers are blue, with the petals 2-10mm long and forming a tube 0.5-1.5mm long at the base. It flowers throughout the year.  Wahlenbergia multicaulis is a coloniser of disturbed sites and grows in a variety of habitats including forest, woodland, scrub, grassland and the edges of watercourses and wetlands. It typically occurs in damp, disturbed sites (with natural or human disturbance of various forms).

3. In New South Wales, Wahlenbergia multicaulis grows mainly in the coastal and tableland districts south from Sydney and the Blue Mountains, and west along the Murray River to Mathoura. This includes the following bioregions: Sydney Basin, South Eastern Highlands, South East Corner, NSW South Western Slopes and Riverina. There are very few records from the Central Coast botanical subdivision.

4. The population in the local government areas of Auburn, Bankstown, Baulkham Hills, Canterbury, Hornsby, Parramatta and Strathfield is disjunct and at the northeastern limit of its geographical range, and is of significant conservation value as it is the only known remaining population in the Central Coast botanical subdivision.

5. The population in the local government areas of Auburn, Bankstown, Baulkham Hills, Canterbury, Hornsby, Parramatta and Strathfield has been reduced by clearing of habitat in the past, and is threatened by clearing, intrusive ballast dumping, deposition of industrial refuse and excavated material.

6. Genetic swamping through hybridisation with other Wahlenbergia species is a significant additional threat (P. Smith pers comm. 2003).

7. The population of Wahlenbergia multicaulis is currently very small with perhaps 100-200 plants at one site though this includes hybrid individuals, a few pure plants at two other sites, and hybrids only at other sites (P. Smith pers comm. 2003). Pure  Wahlenbergia multicaulis is distinguished by a corolla lobe:tube ratio of greater than 4:1 and a distinct constriction of the style less than a third of the way down from the stigmatic lobes (Smith 1992). The hybrids also have a constriction less than a third of the way down the style (distinguishing them from pure  Wahlenbergia littoricola and  Wahlenbergia gracilis), but a corolla lobe:tube ratio of less than 4:1, but greater than 2:1.

8. In view of the above the Scientific Committee is of the opinion that the population of Wahlenbergia multicaulis Benth. in the local government areas of Auburn, Bankstown, Baulkham Hills, Canterbury, Hornsby, Parramatta and Strathfield is facing a high risk of becoming extinct in nature in New South Wales and it is of conservation value at the State or regional level for the following reason: it is disjunct or near the limit of its geographic range. A population is not eligible to be listed as an endangered population if it is a population of a species already listed in Schedule 1.

Associate Professor Paul Adam
Chairperson
Scientific Committee

Proposed Gazettal date: 07/11/03
Exhibition period: 07/11/03 - 19/12/03

References

Smith P. (1992) A revision of the genus Wahlenbergia in Australia.  Telopea 5, 91-175.